chore(3p/nix): unvendor tvix 0.1 r/4098

Nothing is using this now, and we'll likely never pick this up again,
but we learned a lot in the process.

Every now and then this breaks in some bizarre way on channel bumps
and it's just a waste of time to maintain that.

Change-Id: Idcf2f5acd4ca7070ce18d7149cbfc0d967dc0a44
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5632
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

35 files changed, 0 insertions, 6947 deletions

diff --git a/third_party/nix/src/libutil/CMakeLists.txt b/third_party/nix/src/libutil/CMakeLists.txt
deleted file mode 100644
index 0b36929218e8..000000000000
--- a/third_party/nix/src/libutil/CMakeLists.txt
+++ /dev/null
@@ -1,68 +0,0 @@
-# -*- mode: cmake; -*-
-add_library(nixutil SHARED)
-set_property(TARGET nixutil PROPERTY CXX_STANDARD 17)
-include_directories(${PROJECT_BINARY_DIR}) # for config.h
-target_compile_features(nixutil PUBLIC cxx_std_17)
-
-set(HEADER_FILES
-    affinity.hh
-    archive.hh
-    args.hh
-    compression.hh
-    config.hh
-    finally.hh
-    hash.hh
-    istringstream_nocopy.hh
-    json.hh
-    lazy.hh
-    lru-cache.hh
-    monitor-fd.hh
-    pool.hh
-    proto.hh
-    ref.hh
-    serialise.hh
-    status.hh
-    sync.hh
-    thread-pool.hh
-    types.hh
-    util.hh
-    visitor.hh
-    xml-writer.hh
-)
-
-target_sources(nixutil
-  PUBLIC
-    ${HEADER_FILES}
-
-  PRIVATE
-    affinity.cc
-    archive.cc
-    args.cc
-    compression.cc
-    config.cc
-    hash.cc
-    json.cc
-    serialise.cc
-    thread-pool.cc
-    util.cc
-    xml-writer.cc
-)
-
-target_link_libraries(nixutil
-  nixproto
-  absl::strings
-  absl::statusor
-  glog
-  BZip2::BZip2
-  LibLZMA::LibLZMA
-  Boost::context
-  brotlienc
-  brotlidec
-  ssl
-)
-
-# Install header files to include/libutil and mark them for automatic
-# inclusion in targets that link to this one.
-target_include_directories(nixutil PUBLIC "${nix_SOURCE_DIR}/src")
-INSTALL(FILES ${HEADER_FILES} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/nix/libutil)
-INSTALL(TARGETS nixutil DESTINATION ${CMAKE_INSTALL_LIBDIR})
diff --git a/third_party/nix/src/libutil/affinity.cc b/third_party/nix/src/libutil/affinity.cc
deleted file mode 100644
index 03fbe1243992..000000000000
--- a/third_party/nix/src/libutil/affinity.cc
+++ /dev/null
@@ -1,60 +0,0 @@
-#include "libutil/affinity.hh"
-
-#include <glog/logging.h>
-
-#include "libutil/types.hh"
-#include "libutil/util.hh"
-
-#if __linux__
-#include <sched.h>
-#endif
-
-namespace nix {
-
-#if __linux__
-static bool didSaveAffinity = false;
-static cpu_set_t savedAffinity;
-#endif
-
-void setAffinityTo(int cpu) {
-#if __linux__
-  if (sched_getaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1) {
-    return;
-  }
-
-  didSaveAffinity = true;
-  DLOG(INFO) << "locking this thread to CPU " << cpu;
-  cpu_set_t newAffinity;
-  CPU_ZERO(&newAffinity);
-  CPU_SET(cpu, &newAffinity);
-  if (sched_setaffinity(0, sizeof(cpu_set_t), &newAffinity) == -1) {
-    LOG(ERROR) << "failed to lock thread to CPU " << cpu;
-  }
-#endif
-}
-
-int lockToCurrentCPU() {
-#if __linux__
-  int cpu = sched_getcpu();
-  if (cpu != -1) {
-    setAffinityTo(cpu);
-  }
-  return cpu;
-#else
-  return -1;
-#endif
-}
-
-void restoreAffinity() {
-#if __linux__
-  if (!didSaveAffinity) {
-    return;
-  }
-
-  if (sched_setaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1) {
-    LOG(ERROR) << "failed to restore affinity";
-  }
-#endif
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/affinity.hh b/third_party/nix/src/libutil/affinity.hh
deleted file mode 100644
index 5e5ef9b0de0d..000000000000
--- a/third_party/nix/src/libutil/affinity.hh
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-namespace nix {
-
-void setAffinityTo(int cpu);
-int lockToCurrentCPU();
-void restoreAffinity();
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/archive.cc b/third_party/nix/src/libutil/archive.cc
deleted file mode 100644
index e470ad7be6ce..000000000000
--- a/third_party/nix/src/libutil/archive.cc
+++ /dev/null
@@ -1,398 +0,0 @@
-#include "libutil/archive.hh"
-
-#include <algorithm>
-#include <cerrno>
-#include <map>
-#include <vector>
-
-#include <dirent.h>
-#include <fcntl.h>
-#include <glog/logging.h>
-#include <strings.h>  // for strcasecmp
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#include "libutil/config.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-struct ArchiveSettings : Config {
-  Setting<bool> useCaseHack {
-    this,
-#if __APPLE__
-        true,
-#else
-        false,
-#endif
-        "use-case-hack",
-        "Whether to enable a Darwin-specific hack for dealing with file name "
-        "collisions."
-  };
-};
-
-static ArchiveSettings archiveSettings;
-
-static GlobalConfig::Register r1(&archiveSettings);
-
-constexpr std::string_view kCaseHackSuffix = "~nix~case~hack~";
-
-PathFilter defaultPathFilter = [](const Path& /*unused*/) { return true; };
-
-static void dumpContents(const Path& path, size_t size, Sink& sink) {
-  sink << "contents" << size;
-
-  AutoCloseFD fd(open(path.c_str(), O_RDONLY | O_CLOEXEC));
-  if (!fd) {
-    throw SysError(format("opening file '%1%'") % path);
-  }
-
-  std::vector<unsigned char> buf(65536);
-  size_t left = size;
-
-  while (left > 0) {
-    auto n = std::min(left, buf.size());
-    readFull(fd.get(), buf.data(), n);
-    left -= n;
-    sink(buf.data(), n);
-  }
-
-  writePadding(size, sink);
-}
-
-static void dump(const Path& path, Sink& sink, PathFilter& filter) {
-  checkInterrupt();
-
-  struct stat st;
-  if (lstat(path.c_str(), &st) != 0) {
-    throw SysError(format("getting attributes of path '%1%'") % path);
-  }
-
-  sink << "(";
-
-  if (S_ISREG(st.st_mode)) {
-    sink << "type"
-         << "regular";
-    if ((st.st_mode & S_IXUSR) != 0u) {
-      sink << "executable"
-           << "";
-    }
-    dumpContents(path, static_cast<size_t>(st.st_size), sink);
-  }
-
-  else if (S_ISDIR(st.st_mode)) {
-    sink << "type"
-         << "directory";
-
-    /* If we're on a case-insensitive system like macOS, undo
-       the case hack applied by restorePath(). */
-    std::map<std::string, std::string> unhacked;
-    for (auto& i : readDirectory(path)) {
-      if (archiveSettings.useCaseHack) {
-        std::string name(i.name);
-        size_t pos = i.name.find(kCaseHackSuffix);
-        if (pos != std::string::npos) {
-          DLOG(INFO) << "removing case hack suffix from " << path << "/"
-                     << i.name;
-
-          name.erase(pos);
-        }
-        if (unhacked.find(name) != unhacked.end()) {
-          throw Error(format("file name collision in between '%1%' and '%2%'") %
-                      (path + "/" + unhacked[name]) % (path + "/" + i.name));
-        }
-        unhacked[name] = i.name;
-      } else {
-        unhacked[i.name] = i.name;
-      }
-    }
-
-    for (auto& i : unhacked) {
-      if (filter(path + "/" + i.first)) {
-        sink << "entry"
-             << "("
-             << "name" << i.first << "node";
-        dump(path + "/" + i.second, sink, filter);
-        sink << ")";
-      }
-    }
-  }
-
-  else if (S_ISLNK(st.st_mode)) {
-    sink << "type"
-         << "symlink"
-         << "target" << readLink(path);
-
-  } else {
-    throw Error(format("file '%1%' has an unsupported type") % path);
-  }
-
-  sink << ")";
-}
-
-void dumpPath(const Path& path, Sink& sink, PathFilter& filter) {
-  sink << std::string(kNarVersionMagic1);
-  dump(path, sink, filter);
-}
-
-void dumpString(const std::string& s, Sink& sink) {
-  sink << std::string(kNarVersionMagic1) << "("
-       << "type"
-       << "regular"
-       << "contents" << s << ")";
-}
-
-static SerialisationError badArchive(const std::string& s) {
-  return SerialisationError("bad archive: " + s);
-}
-
-#if 0
-static void skipGeneric(Source & source)
-{
-    if (readString(source) == "(") {
-        while (readString(source) != ")")
-            skipGeneric(source);
-    }
-}
-#endif
-
-static void parseContents(ParseSink& sink, Source& source, const Path& path) {
-  unsigned long long size = readLongLong(source);
-
-  sink.preallocateContents(size);
-
-  unsigned long long left = size;
-  std::vector<unsigned char> buf(65536);
-
-  while (left != 0u) {
-    checkInterrupt();
-    auto n = buf.size();
-    if (static_cast<unsigned long long>(n) > left) {
-      n = left;
-    }
-    source(buf.data(), n);
-    sink.receiveContents(buf.data(), n);
-    left -= n;
-  }
-
-  readPadding(size, source);
-}
-
-struct CaseInsensitiveCompare {
-  bool operator()(const std::string& a, const std::string& b) const {
-    return strcasecmp(a.c_str(), b.c_str()) < 0;
-  }
-};
-
-static void parse(ParseSink& sink, Source& source, const Path& path) {
-  std::string s;
-
-  s = readString(source);
-  if (s != "(") {
-    throw badArchive("expected open tag");
-  }
-
-  enum { tpUnknown, tpRegular, tpDirectory, tpSymlink } type = tpUnknown;
-
-  std::map<Path, int, CaseInsensitiveCompare> names;
-
-  while (true) {
-    checkInterrupt();
-
-    s = readString(source);
-
-    if (s == ")") {
-      break;
-    }
-
-    if (s == "type") {
-      if (type != tpUnknown) {
-        throw badArchive("multiple type fields");
-      }
-      std::string t = readString(source);
-
-      if (t == "regular") {
-        type = tpRegular;
-        sink.createRegularFile(path);
-      }
-
-      else if (t == "directory") {
-        sink.createDirectory(path);
-        type = tpDirectory;
-      }
-
-      else if (t == "symlink") {
-        type = tpSymlink;
-      }
-
-      else {
-        throw badArchive("unknown file type " + t);
-      }
-
-    }
-
-    else if (s == "contents" && type == tpRegular) {
-      parseContents(sink, source, path);
-    }
-
-    else if (s == "executable" && type == tpRegular) {
-      auto s = readString(source);
-      if (!s.empty()) {
-        throw badArchive("executable marker has non-empty value");
-      }
-      sink.isExecutable();
-    }
-
-    else if (s == "entry" && type == tpDirectory) {
-      std::string name;
-      std::string prevName;
-
-      s = readString(source);
-      if (s != "(") {
-        throw badArchive("expected open tag");
-      }
-
-      while (true) {
-        checkInterrupt();
-
-        s = readString(source);
-
-        if (s == ")") {
-          break;
-        }
-        if (s == "name") {
-          name = readString(source);
-          if (name.empty() || name == "." || name == ".." ||
-              name.find('/') != std::string::npos ||
-              name.find(static_cast<char>(0)) != std::string::npos) {
-            throw Error(format("NAR contains invalid file name '%1%'") % name);
-          }
-          if (name <= prevName) {
-            throw Error("NAR directory is not sorted");
-          }
-          prevName = name;
-          if (archiveSettings.useCaseHack) {
-            auto i = names.find(name);
-            if (i != names.end()) {
-              DLOG(INFO) << "case collision between '" << i->first << "' and '"
-                         << name << "'";
-              name += kCaseHackSuffix;
-              name += std::to_string(++i->second);
-            } else {
-              names[name] = 0;
-            }
-          }
-        } else if (s == "node") {
-          if (s.empty()) {
-            throw badArchive("entry name missing");
-          }
-          parse(sink, source, path + "/" + name);
-        } else {
-          throw badArchive("unknown field " + s);
-        }
-      }
-    }
-
-    else if (s == "target" && type == tpSymlink) {
-      std::string target = readString(source);
-      sink.createSymlink(path, target);
-    }
-
-    else {
-      throw badArchive("unknown field " + s);
-    }
-  }
-}
-
-void parseDump(ParseSink& sink, Source& source) {
-  std::string version;
-  try {
-    version = readString(source, kNarVersionMagic1.size());
-  } catch (SerialisationError& e) {
-    /* This generally means the integer at the start couldn't be
-       decoded.  Ignore and throw the exception below. */
-  }
-  if (version != kNarVersionMagic1) {
-    throw badArchive("input doesn't look like a Nix archive");
-  }
-  parse(sink, source, "");
-}
-
-struct RestoreSink : ParseSink {
-  Path dstPath;
-  AutoCloseFD fd;
-
-  void createDirectory(const Path& path) override {
-    Path p = dstPath + path;
-    if (mkdir(p.c_str(), 0777) == -1) {
-      throw SysError(format("creating directory '%1%'") % p);
-    }
-  };
-
-  void createRegularFile(const Path& path) override {
-    Path p = dstPath + path;
-    fd = AutoCloseFD(
-        open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY | O_CLOEXEC, 0666));
-    if (!fd) {
-      throw SysError(format("creating file '%1%'") % p);
-    }
-  }
-
-  void isExecutable() override {
-    struct stat st;
-    if (fstat(fd.get(), &st) == -1) {
-      throw SysError("fstat");
-    }
-    if (fchmod(fd.get(), st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1) {
-      throw SysError("fchmod");
-    }
-  }
-
-  void preallocateContents(unsigned long long len) override {
-#if HAVE_POSIX_FALLOCATE
-    if (len != 0u) {
-      errno = posix_fallocate(fd.get(), 0, len);
-      /* Note that EINVAL may indicate that the underlying
-         filesystem doesn't support preallocation (e.g. on
-         OpenSolaris).  Since preallocation is just an
-         optimisation, ignore it. */
-      if (errno && errno != EINVAL && errno != EOPNOTSUPP && errno != ENOSYS) {
-        throw SysError(format("preallocating file of %1% bytes") % len);
-      }
-    }
-#endif
-  }
-
-  void receiveContents(unsigned char* data, unsigned int len) override {
-    writeFull(fd.get(), data, len);
-  }
-
-  void createSymlink(const Path& path, const std::string& target) override {
-    Path p = dstPath + path;
-    nix::createSymlink(target, p);
-  }
-};
-
-void restorePath(const Path& path, Source& source) {
-  RestoreSink sink;
-  sink.dstPath = path;
-  parseDump(sink, source);
-}
-
-void copyNAR(Source& source, Sink& sink) {
-  // FIXME: if 'source' is the output of dumpPath() followed by EOF,
-  // we should just forward all data directly without parsing.
-
-  ParseSink parseSink; /* null sink; just parse the NAR */
-
-  LambdaSource wrapper([&](unsigned char* data, size_t len) {
-    auto n = source.read(data, len);
-    sink(data, n);
-    return n;
-  });
-
-  parseDump(parseSink, wrapper);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/archive.hh b/third_party/nix/src/libutil/archive.hh
deleted file mode 100644
index 396627878541..000000000000
--- a/third_party/nix/src/libutil/archive.hh
+++ /dev/null
@@ -1,77 +0,0 @@
-#pragma once
-
-#include "libutil/serialise.hh"
-#include "libutil/types.hh"
-
-namespace nix {
-
-/* dumpPath creates a Nix archive of the specified path.  The format
-   is as follows:
-
-   IF path points to a REGULAR FILE:
-     dump(path) = attrs(
-       [ ("type", "regular")
-       , ("contents", contents(path))
-       ])
-
-   IF path points to a DIRECTORY:
-     dump(path) = attrs(
-       [ ("type", "directory")
-       , ("entries", concat(map(f, sort(entries(path)))))
-       ])
-       where f(fn) = attrs(
-         [ ("name", fn)
-         , ("file", dump(path + "/" + fn))
-         ])
-
-   where:
-
-     attrs(as) = concat(map(attr, as)) + encN(0)
-     attrs((a, b)) = encS(a) + encS(b)
-
-     encS(s) = encN(len(s)) + s + (padding until next 64-bit boundary)
-
-     encN(n) = 64-bit little-endian encoding of n.
-
-     contents(path) = the contents of a regular file.
-
-     sort(strings) = lexicographic sort by 8-bit value (strcmp).
-
-     entries(path) = the entries of a directory, without `.' and
-     `..'.
-
-     `+' denotes string concatenation. */
-
-void dumpPath(const Path& path, Sink& sink,
-              PathFilter& filter = defaultPathFilter);
-
-void dumpString(const std::string& s, Sink& sink);
-
-/* FIXME: fix this API, it sucks. */
-struct ParseSink {
-  virtual void createDirectory(const Path& path){};
-
-  virtual void createRegularFile(const Path& path){};
-  virtual void isExecutable(){};
-  virtual void preallocateContents(unsigned long long size){};
-  virtual void receiveContents(unsigned char* data, unsigned int len){};
-
-  virtual void createSymlink(const Path& path, const std::string& target){};
-};
-
-struct TeeSink : ParseSink {
-  TeeSource source;
-
-  explicit TeeSink(Source& source) : source(source) {}
-};
-
-void parseDump(ParseSink& sink, Source& source);
-
-void restorePath(const Path& path, Source& source);
-
-/* Read a NAR from 'source' and write it to 'sink'. */
-void copyNAR(Source& source, Sink& sink);
-
-constexpr std::string_view kNarVersionMagic1 = "nix-archive-1";
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/args.cc b/third_party/nix/src/libutil/args.cc
deleted file mode 100644
index 2be8a1b0ce2a..000000000000
--- a/third_party/nix/src/libutil/args.cc
+++ /dev/null
@@ -1,219 +0,0 @@
-#include "libutil/args.hh"
-
-#include "libutil/hash.hh"
-
-namespace nix {
-
-Args::FlagMaker Args::mkFlag() { return FlagMaker(*this); }
-
-Args::FlagMaker::~FlagMaker() {
-  assert(!flag->longName.empty());
-  args.longFlags[flag->longName] = flag;
-  if (flag->shortName != 0) {
-    args.shortFlags[flag->shortName] = flag;
-  }
-}
-
-void Args::parseCmdline(const Strings& _cmdline) {
-  Strings pendingArgs;
-  bool dashDash = false;
-
-  Strings cmdline(_cmdline);
-
-  for (auto pos = cmdline.begin(); pos != cmdline.end();) {
-    auto arg = *pos;
-
-    /* Expand compound dash options (i.e., `-qlf' -> `-q -l -f',
-       `-j3` -> `-j 3`). */
-    if (!dashDash && arg.length() > 2 && arg[0] == '-' && arg[1] != '-' &&
-        (isalpha(arg[1]) != 0)) {
-      *pos = std::string("-") + arg[1];
-      auto next = pos;
-      ++next;
-      for (unsigned int j = 2; j < arg.length(); j++) {
-        if (isalpha(arg[j]) != 0) {
-          cmdline.insert(next, std::string("-") + arg[j]);
-        } else {
-          cmdline.insert(next, std::string(arg, j));
-          break;
-        }
-      }
-      arg = *pos;
-    }
-
-    if (!dashDash && arg == "--") {
-      dashDash = true;
-      ++pos;
-    } else if (!dashDash && std::string(arg, 0, 1) == "-") {
-      if (!processFlag(pos, cmdline.end())) {
-        throw UsageError(format("unrecognised flag '%1%'") % arg);
-      }
-    } else {
-      pendingArgs.push_back(*pos++);
-      if (processArgs(pendingArgs, false)) {
-        pendingArgs.clear();
-      }
-    }
-  }
-
-  processArgs(pendingArgs, true);
-}
-
-void Args::printHelp(const std::string& programName, std::ostream& out) {
-  std::cout << "Usage: " << programName << " <FLAGS>...";
-  for (auto& exp : expectedArgs) {
-    std::cout << renderLabels({exp.label});
-    // FIXME: handle arity > 1
-    if (exp.arity == 0) {
-      std::cout << "...";
-    }
-    if (exp.optional) {
-      std::cout << "?";
-    }
-  }
-  std::cout << "\n";
-
-  auto s = description();
-  if (!s.empty()) {
-    std::cout << "\nSummary: " << s << ".\n";
-  }
-
-  if (!longFlags.empty() != 0u) {
-    std::cout << "\n";
-    std::cout << "Flags:\n";
-    printFlags(out);
-  }
-}
-
-void Args::printFlags(std::ostream& out) {
-  Table2 table;
-  for (auto& flag : longFlags) {
-    if (hiddenCategories.count(flag.second->category) != 0u) {
-      continue;
-    }
-    table.push_back(std::make_pair(
-        (flag.second->shortName != 0
-             ? std::string("-") + flag.second->shortName + ", "
-             : "    ") +
-            "--" + flag.first + renderLabels(flag.second->labels),
-        flag.second->description));
-  }
-  printTable(out, table);
-}
-
-bool Args::processFlag(Strings::iterator& pos, Strings::iterator end) {
-  assert(pos != end);
-
-  auto process = [&](const std::string& name, const Flag& flag) -> bool {
-    ++pos;
-    std::vector<std::string> args;
-    for (size_t n = 0; n < flag.arity; ++n) {
-      if (pos == end) {
-        if (flag.arity == ArityAny) {
-          break;
-        }
-        throw UsageError(format("flag '%1%' requires %2% argument(s)") % name %
-                         flag.arity);
-      }
-      args.push_back(*pos++);
-    }
-    flag.handler(std::move(args));
-    return true;
-  };
-
-  if (std::string(*pos, 0, 2) == "--") {
-    auto i = longFlags.find(std::string(*pos, 2));
-    if (i == longFlags.end()) {
-      return false;
-    }
-    return process("--" + i->first, *i->second);
-  }
-
-  if (std::string(*pos, 0, 1) == "-" && pos->size() == 2) {
-    auto c = (*pos)[1];
-    auto i = shortFlags.find(c);
-    if (i == shortFlags.end()) {
-      return false;
-    }
-    return process(std::string("-") + c, *i->second);
-  }
-
-  return false;
-}
-
-bool Args::processArgs(const Strings& args, bool finish) {
-  if (expectedArgs.empty()) {
-    if (!args.empty()) {
-      throw UsageError(format("unexpected argument '%1%'") % args.front());
-    }
-    return true;
-  }
-
-  auto& exp = expectedArgs.front();
-
-  bool res = false;
-
-  if ((exp.arity == 0 && finish) ||
-      (exp.arity > 0 && args.size() == exp.arity)) {
-    std::vector<std::string> ss;
-    for (auto& s : args) {
-      ss.push_back(s);
-    }
-    exp.handler(std::move(ss));
-    expectedArgs.pop_front();
-    res = true;
-  }
-
-  if (finish && !expectedArgs.empty() && !expectedArgs.front().optional) {
-    throw UsageError("more arguments are required");
-  }
-
-  return res;
-}
-
-Args::FlagMaker& Args::FlagMaker::mkHashTypeFlag(HashType* ht) {
-  arity(1);
-  label("type");
-  description("hash algorithm ('md5', 'sha1', 'sha256', or 'sha512')");
-  handler([ht](const std::string& s) {
-    *ht = parseHashType(s);
-    if (*ht == htUnknown) {
-      throw UsageError("unknown hash type '%1%'", s);
-    }
-  });
-  return *this;
-}
-
-Strings argvToStrings(int argc, char** argv) {
-  Strings args;
-  argc--;
-  argv++;
-  while ((argc--) != 0) {
-    args.push_back(*argv++);
-  }
-  return args;
-}
-
-std::string renderLabels(const Strings& labels) {
-  std::string res;
-  for (auto label : labels) {
-    for (auto& c : label) {
-      c = std::toupper(c);
-    }
-    res += " <" + label + ">";
-  }
-  return res;
-}
-
-void printTable(std::ostream& out, const Table2& table) {
-  size_t max = 0;
-  for (auto& row : table) {
-    max = std::max(max, row.first.size());
-  }
-  for (auto& row : table) {
-    out << "  " << row.first << std::string(max - row.first.size() + 2, ' ')
-        << row.second << "\n";
-  }
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/args.hh b/third_party/nix/src/libutil/args.hh
deleted file mode 100644
index bb1ef43912bb..000000000000
--- a/third_party/nix/src/libutil/args.hh
+++ /dev/null
@@ -1,221 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include <map>
-#include <memory>
-
-#include <absl/strings/numbers.h>
-
-#include "libutil/util.hh"
-
-namespace nix {
-
-MakeError(UsageError, Error);
-
-enum HashType : char;
-
-class Args {
- public:
-  /* Parse the command line, throwing a UsageError if something goes
-     wrong. */
-  void parseCmdline(const Strings& cmdline);
-
-  virtual void printHelp(const std::string& programName, std::ostream& out);
-
-  virtual std::string description() { return ""; }
-
- protected:
-  static const size_t ArityAny = std::numeric_limits<size_t>::max();
-
-  /* Flags. */
-  struct Flag {
-    typedef std::shared_ptr<Flag> ptr;
-    std::string longName;
-    char shortName = 0;
-    std::string description;
-    Strings labels;
-    size_t arity = 0;
-    std::function<void(std::vector<std::string>)> handler;
-    std::string category;
-  };
-
-  std::map<std::string, Flag::ptr> longFlags;
-  std::map<char, Flag::ptr> shortFlags;
-
-  virtual bool processFlag(Strings::iterator& pos, Strings::iterator end);
-
-  virtual void printFlags(std::ostream& out);
-
-  /* Positional arguments. */
-  struct ExpectedArg {
-    std::string label;
-    size_t arity;  // 0 = any
-    bool optional;
-    std::function<void(std::vector<std::string>)> handler;
-  };
-
-  std::list<ExpectedArg> expectedArgs;
-
-  virtual bool processArgs(const Strings& args, bool finish);
-
-  std::set<std::string> hiddenCategories;
-
- public:
-  class FlagMaker {
-    Args& args;
-    Flag::ptr flag;
-    friend class Args;
-    explicit FlagMaker(Args& args)
-        : args(args), flag(std::make_shared<Flag>()){};
-
-   public:
-    ~FlagMaker();
-    FlagMaker& longName(const std::string& s) {
-      flag->longName = s;
-      return *this;
-    };
-    FlagMaker& shortName(char s) {
-      flag->shortName = s;
-      return *this;
-    };
-    FlagMaker& description(const std::string& s) {
-      flag->description = s;
-      return *this;
-    };
-    FlagMaker& label(const std::string& l) {
-      flag->arity = 1;
-      flag->labels = {l};
-      return *this;
-    };
-    FlagMaker& labels(const Strings& ls) {
-      flag->arity = ls.size();
-      flag->labels = ls;
-      return *this;
-    };
-    FlagMaker& arity(size_t arity) {
-      flag->arity = arity;
-      return *this;
-    };
-    FlagMaker& handler(std::function<void(std::vector<std::string>)> handler) {
-      flag->handler = handler;
-      return *this;
-    };
-    FlagMaker& handler(std::function<void()> handler) {
-      flag->handler = [handler](std::vector<std::string>) { handler(); };
-      return *this;
-    };
-    FlagMaker& handler(std::function<void(std::string)> handler) {
-      flag->arity = 1;
-      flag->handler = [handler](std::vector<std::string> ss) {
-        handler(std::move(ss[0]));
-      };
-      return *this;
-    };
-    FlagMaker& category(const std::string& s) {
-      flag->category = s;
-      return *this;
-    };
-
-    template <class T>
-    FlagMaker& dest(T* dest) {
-      flag->arity = 1;
-      flag->handler = [=](std::vector<std::string> ss) { *dest = ss[0]; };
-      return *this;
-    }
-
-    template <class T>
-    FlagMaker& set(T* dest, const T& val) {
-      flag->arity = 0;
-      flag->handler = [=](std::vector<std::string> ss) { *dest = val; };
-      return *this;
-    }
-
-    FlagMaker& mkHashTypeFlag(HashType* ht);
-  };
-
-  FlagMaker mkFlag();
-
-  /* Helper functions for constructing flags / positional
-     arguments. */
-
-  void mkFlag1(char shortName, const std::string& longName,
-               const std::string& label, const std::string& description,
-               std::function<void(std::string)> fun) {
-    mkFlag()
-        .shortName(shortName)
-        .longName(longName)
-        .labels({label})
-        .description(description)
-        .arity(1)
-        .handler([=](std::vector<std::string> ss) { fun(ss[0]); });
-  }
-
-  void mkFlag(char shortName, const std::string& name,
-              const std::string& description, bool* dest) {
-    mkFlag(shortName, name, description, dest, true);
-  }
-
-  template <class T>
-  void mkFlag(char shortName, const std::string& longName,
-              const std::string& description, T* dest, const T& value) {
-    mkFlag()
-        .shortName(shortName)
-        .longName(longName)
-        .description(description)
-        .handler([=](std::vector<std::string> ss) { *dest = value; });
-  }
-
-  template <class I>
-  void mkIntFlag(char shortName, const std::string& longName,
-                 const std::string& description, I* dest) {
-    mkFlag<I>(shortName, longName, description, [=](I n) { *dest = n; });
-  }
-
-  template <class I>
-  void mkFlag(char shortName, const std::string& longName,
-              const std::string& description, std::function<void(I)> fun) {
-    mkFlag()
-        .shortName(shortName)
-        .longName(longName)
-        .labels({"N"})
-        .description(description)
-        .arity(1)
-        .handler([=](std::vector<std::string> ss) {
-          I n;
-          if (!absl::SimpleAtoi(ss[0], &n)) {
-            throw UsageError("flag '--%s' requires a integer argument",
-                             longName);
-          }
-          fun(n);
-        });
-  }
-
-  /* Expect a string argument. */
-  void expectArg(const std::string& label, std::string* dest,
-                 bool optional = false) {
-    expectedArgs.push_back(
-        ExpectedArg{label, 1, optional,
-                    [=](std::vector<std::string> ss) { *dest = ss[0]; }});
-  }
-
-  /* Expect 0 or more arguments. */
-  void expectArgs(const std::string& label, std::vector<std::string>* dest) {
-    expectedArgs.push_back(ExpectedArg{
-        label, 0, false,
-        [=](std::vector<std::string> ss) { *dest = std::move(ss); }});
-  }
-
-  friend class MultiCommand;
-};
-
-Strings argvToStrings(int argc, char** argv);
-
-/* Helper function for rendering argument labels. */
-std::string renderLabels(const Strings& labels);
-
-/* Helper function for printing 2-column tables. */
-using Table2 = std::vector<std::pair<std::string, std::string> >;
-
-void printTable(std::ostream& out, const Table2& table);
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/compression.cc b/third_party/nix/src/libutil/compression.cc
deleted file mode 100644
index d0895ca5fda4..000000000000
--- a/third_party/nix/src/libutil/compression.cc
+++ /dev/null
@@ -1,400 +0,0 @@
-#include "libutil/compression.hh"
-
-#include <cstdio>
-#include <cstring>
-#include <iostream>
-
-#include <brotli/decode.h>
-#include <brotli/encode.h>
-#include <bzlib.h>
-#include <glog/logging.h>
-#include <lzma.h>
-
-#include "libutil/finally.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-// Don't feed brotli too much at once.
-struct ChunkedCompressionSink : CompressionSink {
-  uint8_t outbuf[32 * 1024];
-
-  void write(const unsigned char* data, size_t len) override {
-    const size_t CHUNK_SIZE = sizeof(outbuf) << 2;
-    while (len != 0u) {
-      size_t n = std::min(CHUNK_SIZE, len);
-      writeInternal(data, n);
-      data += n;
-      len -= n;
-    }
-  }
-
-  virtual void writeInternal(const unsigned char* data, size_t len) = 0;
-};
-
-struct NoneSink : CompressionSink {
-  Sink& nextSink;
-  explicit NoneSink(Sink& nextSink) : nextSink(nextSink) {}
-  void finish() override { flush(); }
-  void write(const unsigned char* data, size_t len) override {
-    nextSink(data, len);
-  }
-};
-
-struct XzDecompressionSink : CompressionSink {
-  Sink& nextSink;
-  uint8_t outbuf[BUFSIZ];
-  lzma_stream strm = LZMA_STREAM_INIT;
-  bool finished = false;
-
-  explicit XzDecompressionSink(Sink& nextSink) : nextSink(nextSink) {
-    lzma_ret ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
-    if (ret != LZMA_OK) {
-      throw CompressionError("unable to initialise lzma decoder");
-    }
-
-    strm.next_out = outbuf;
-    strm.avail_out = sizeof(outbuf);
-  }
-
-  ~XzDecompressionSink() override { lzma_end(&strm); }
-
-  void finish() override {
-    CompressionSink::flush();
-    write(nullptr, 0);
-  }
-
-  void write(const unsigned char* data, size_t len) override {
-    strm.next_in = data;
-    strm.avail_in = len;
-
-    while (!finished && ((data == nullptr) || (strm.avail_in != 0u))) {
-      checkInterrupt();
-
-      lzma_ret ret = lzma_code(&strm, data != nullptr ? LZMA_RUN : LZMA_FINISH);
-      if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
-        throw CompressionError("error %d while decompressing xz file", ret);
-      }
-
-      finished = ret == LZMA_STREAM_END;
-
-      if (strm.avail_out < sizeof(outbuf) || strm.avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - strm.avail_out);
-        strm.next_out = outbuf;
-        strm.avail_out = sizeof(outbuf);
-      }
-    }
-  }
-};
-
-struct BzipDecompressionSink : ChunkedCompressionSink {
-  Sink& nextSink;
-  bz_stream strm;
-  bool finished = false;
-
-  explicit BzipDecompressionSink(Sink& nextSink) : nextSink(nextSink) {
-    memset(&strm, 0, sizeof(strm));
-    int ret = BZ2_bzDecompressInit(&strm, 0, 0);
-    if (ret != BZ_OK) {
-      throw CompressionError("unable to initialise bzip2 decoder");
-    }
-
-    strm.next_out = reinterpret_cast<char*>(outbuf);
-    strm.avail_out = sizeof(outbuf);
-  }
-
-  ~BzipDecompressionSink() override { BZ2_bzDecompressEnd(&strm); }
-
-  void finish() override {
-    flush();
-    write(nullptr, 0);
-  }
-
-  void writeInternal(const unsigned char* data, size_t len) override {
-    assert(len <= std::numeric_limits<decltype(strm.avail_in)>::max());
-
-    strm.next_in = (char*)data;
-    strm.avail_in = len;
-
-    while (strm.avail_in != 0u) {
-      checkInterrupt();
-
-      int ret = BZ2_bzDecompress(&strm);
-      if (ret != BZ_OK && ret != BZ_STREAM_END) {
-        throw CompressionError("error while decompressing bzip2 file");
-      }
-
-      finished = ret == BZ_STREAM_END;
-
-      if (strm.avail_out < sizeof(outbuf) || strm.avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - strm.avail_out);
-        strm.next_out = reinterpret_cast<char*>(outbuf);
-        strm.avail_out = sizeof(outbuf);
-      }
-    }
-  }
-};
-
-struct BrotliDecompressionSink : ChunkedCompressionSink {
-  Sink& nextSink;
-  BrotliDecoderState* state;
-  bool finished = false;
-
-  explicit BrotliDecompressionSink(Sink& nextSink) : nextSink(nextSink) {
-    state = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
-    if (state == nullptr) {
-      throw CompressionError("unable to initialize brotli decoder");
-    }
-  }
-
-  ~BrotliDecompressionSink() override { BrotliDecoderDestroyInstance(state); }
-
-  void finish() override {
-    flush();
-    writeInternal(nullptr, 0);
-  }
-
-  void writeInternal(const unsigned char* data, size_t len) override {
-    const uint8_t* next_in = data;
-    size_t avail_in = len;
-    uint8_t* next_out = outbuf;
-    size_t avail_out = sizeof(outbuf);
-
-    while (!finished && ((data == nullptr) || (avail_in != 0u))) {
-      checkInterrupt();
-
-      if (BrotliDecoderDecompressStream(state, &avail_in, &next_in, &avail_out,
-                                        &next_out, nullptr) == 0u) {
-        throw CompressionError("error while decompressing brotli file");
-      }
-
-      if (avail_out < sizeof(outbuf) || avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - avail_out);
-        next_out = outbuf;
-        avail_out = sizeof(outbuf);
-      }
-
-      finished = (BrotliDecoderIsFinished(state) != 0);
-    }
-  }
-};
-
-ref<std::string> decompress(const std::string& method, const std::string& in) {
-  StringSink ssink;
-  auto sink = makeDecompressionSink(method, ssink);
-  (*sink)(in);
-  sink->finish();
-  return ssink.s;
-}
-
-ref<CompressionSink> makeDecompressionSink(const std::string& method,
-                                           Sink& nextSink) {
-  if (method == "none" || method.empty()) {
-    return make_ref<NoneSink>(nextSink);
-  }
-  if (method == "xz") {
-    return make_ref<XzDecompressionSink>(nextSink);
-  } else if (method == "bzip2") {
-    return make_ref<BzipDecompressionSink>(nextSink);
-  } else if (method == "br") {
-    return make_ref<BrotliDecompressionSink>(nextSink);
-  } else {
-    throw UnknownCompressionMethod("unknown compression method '%s'", method);
-  }
-}
-
-struct XzCompressionSink : CompressionSink {
-  Sink& nextSink;
-  uint8_t outbuf[BUFSIZ];
-  lzma_stream strm = LZMA_STREAM_INIT;
-  bool finished = false;
-
-  XzCompressionSink(Sink& nextSink, bool parallel) : nextSink(nextSink) {
-    lzma_ret ret;
-    bool done = false;
-
-    if (parallel) {
-      lzma_mt mt_options = {};
-      mt_options.flags = 0;
-      mt_options.timeout = 300;  // Using the same setting as the xz cmd line
-      mt_options.preset = LZMA_PRESET_DEFAULT;
-      mt_options.filters = NULL;
-      mt_options.check = LZMA_CHECK_CRC64;
-      mt_options.threads = lzma_cputhreads();
-      mt_options.block_size = 0;
-      if (mt_options.threads == 0) {
-        mt_options.threads = 1;
-      }
-      // FIXME: maybe use lzma_stream_encoder_mt_memusage() to control the
-      // number of threads.
-      ret = lzma_stream_encoder_mt(&strm, &mt_options);
-      done = true;
-    }
-
-    if (!done) {
-      ret = lzma_easy_encoder(&strm, 6, LZMA_CHECK_CRC64);
-    }
-
-    if (ret != LZMA_OK) {
-      throw CompressionError("unable to initialise lzma encoder");
-    }
-
-    // FIXME: apply the x86 BCJ filter?
-
-    strm.next_out = outbuf;
-    strm.avail_out = sizeof(outbuf);
-  }
-
-  ~XzCompressionSink() override { lzma_end(&strm); }
-
-  void finish() override {
-    CompressionSink::flush();
-    write(nullptr, 0);
-  }
-
-  void write(const unsigned char* data, size_t len) override {
-    strm.next_in = data;
-    strm.avail_in = len;
-
-    while (!finished && ((data == nullptr) || (strm.avail_in != 0u))) {
-      checkInterrupt();
-
-      lzma_ret ret = lzma_code(&strm, data != nullptr ? LZMA_RUN : LZMA_FINISH);
-      if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
-        throw CompressionError("error %d while compressing xz file", ret);
-      }
-
-      finished = ret == LZMA_STREAM_END;
-
-      if (strm.avail_out < sizeof(outbuf) || strm.avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - strm.avail_out);
-        strm.next_out = outbuf;
-        strm.avail_out = sizeof(outbuf);
-      }
-    }
-  }
-};
-
-struct BzipCompressionSink : ChunkedCompressionSink {
-  Sink& nextSink;
-  bz_stream strm;
-  bool finished = false;
-
-  explicit BzipCompressionSink(Sink& nextSink) : nextSink(nextSink) {
-    memset(&strm, 0, sizeof(strm));
-    int ret = BZ2_bzCompressInit(&strm, 9, 0, 30);
-    if (ret != BZ_OK) {
-      throw CompressionError("unable to initialise bzip2 encoder");
-    }
-
-    strm.next_out = reinterpret_cast<char*>(outbuf);
-    strm.avail_out = sizeof(outbuf);
-  }
-
-  ~BzipCompressionSink() override { BZ2_bzCompressEnd(&strm); }
-
-  void finish() override {
-    flush();
-    writeInternal(nullptr, 0);
-  }
-
-  void writeInternal(const unsigned char* data, size_t len) override {
-    assert(len <= std::numeric_limits<decltype(strm.avail_in)>::max());
-
-    strm.next_in = (char*)data;
-    strm.avail_in = len;
-
-    while (!finished && ((data == nullptr) || (strm.avail_in != 0u))) {
-      checkInterrupt();
-
-      int ret = BZ2_bzCompress(&strm, data != nullptr ? BZ_RUN : BZ_FINISH);
-      if (ret != BZ_RUN_OK && ret != BZ_FINISH_OK && ret != BZ_STREAM_END) {
-        throw CompressionError("error %d while compressing bzip2 file", ret);
-      }
-
-      finished = ret == BZ_STREAM_END;
-
-      if (strm.avail_out < sizeof(outbuf) || strm.avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - strm.avail_out);
-        strm.next_out = reinterpret_cast<char*>(outbuf);
-        strm.avail_out = sizeof(outbuf);
-      }
-    }
-  }
-};
-
-struct BrotliCompressionSink : ChunkedCompressionSink {
-  Sink& nextSink;
-  uint8_t outbuf[BUFSIZ];
-  BrotliEncoderState* state;
-  bool finished = false;
-
-  explicit BrotliCompressionSink(Sink& nextSink) : nextSink(nextSink) {
-    state = BrotliEncoderCreateInstance(nullptr, nullptr, nullptr);
-    if (state == nullptr) {
-      throw CompressionError("unable to initialise brotli encoder");
-    }
-  }
-
-  ~BrotliCompressionSink() override { BrotliEncoderDestroyInstance(state); }
-
-  void finish() override {
-    flush();
-    writeInternal(nullptr, 0);
-  }
-
-  void writeInternal(const unsigned char* data, size_t len) override {
-    const uint8_t* next_in = data;
-    size_t avail_in = len;
-    uint8_t* next_out = outbuf;
-    size_t avail_out = sizeof(outbuf);
-
-    while (!finished && ((data == nullptr) || (avail_in != 0u))) {
-      checkInterrupt();
-
-      if (BrotliEncoderCompressStream(state,
-                                      data != nullptr ? BROTLI_OPERATION_PROCESS
-                                                      : BROTLI_OPERATION_FINISH,
-                                      &avail_in, &next_in, &avail_out,
-                                      &next_out, nullptr) == 0) {
-        throw CompressionError("error while compressing brotli compression");
-      }
-
-      if (avail_out < sizeof(outbuf) || avail_in == 0) {
-        nextSink(outbuf, sizeof(outbuf) - avail_out);
-        next_out = outbuf;
-        avail_out = sizeof(outbuf);
-      }
-
-      finished = (BrotliEncoderIsFinished(state) != 0);
-    }
-  }
-};
-
-ref<CompressionSink> makeCompressionSink(const std::string& method,
-                                         Sink& nextSink, const bool parallel) {
-  if (method == "none") {
-    return make_ref<NoneSink>(nextSink);
-  }
-  if (method == "xz") {
-    return make_ref<XzCompressionSink>(nextSink, parallel);
-  } else if (method == "bzip2") {
-    return make_ref<BzipCompressionSink>(nextSink);
-  } else if (method == "br") {
-    return make_ref<BrotliCompressionSink>(nextSink);
-  } else {
-    throw UnknownCompressionMethod(format("unknown compression method '%s'") %
-                                   method);
-  }
-}
-
-ref<std::string> compress(const std::string& method, const std::string& in,
-                          const bool parallel) {
-  StringSink ssink;
-  auto sink = makeCompressionSink(method, ssink, parallel);
-  (*sink)(in);
-  sink->finish();
-  return ssink.s;
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/compression.hh b/third_party/nix/src/libutil/compression.hh
deleted file mode 100644
index 8ec340ab7447..000000000000
--- a/third_party/nix/src/libutil/compression.hh
+++ /dev/null
@@ -1,31 +0,0 @@
-#pragma once
-
-#include <string>
-
-#include "libutil/ref.hh"
-#include "libutil/serialise.hh"
-#include "libutil/types.hh"
-
-namespace nix {
-
-struct CompressionSink : BufferedSink {
-  virtual void finish() = 0;
-};
-
-ref<std::string> decompress(const std::string& method, const std::string& in);
-
-ref<CompressionSink> makeDecompressionSink(const std::string& method,
-                                           Sink& nextSink);
-
-ref<std::string> compress(const std::string& method, const std::string& in,
-                          const bool parallel = false);
-
-ref<CompressionSink> makeCompressionSink(const std::string& method,
-                                         Sink& nextSink,
-                                         const bool parallel = false);
-
-MakeError(UnknownCompressionMethod, Error);
-
-MakeError(CompressionError, Error);
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/config.cc b/third_party/nix/src/libutil/config.cc
deleted file mode 100644
index 7c6e7af48752..000000000000
--- a/third_party/nix/src/libutil/config.cc
+++ /dev/null
@@ -1,370 +0,0 @@
-#include "libutil/config.hh"
-
-#include <string>
-#include <utility>
-#include <vector>
-
-#include <absl/strings/numbers.h>
-#include <absl/strings/str_split.h>
-#include <absl/strings/string_view.h>
-#include <glog/logging.h>
-
-#include "libutil/args.hh"
-#include "libutil/json.hh"
-
-namespace nix {
-
-bool Config::set(const std::string& name, const std::string& value) {
-  auto i = _settings.find(name);
-  if (i == _settings.end()) {
-    return false;
-  }
-  i->second.setting->set(value);
-  i->second.setting->overriden = true;
-  return true;
-}
-
-void Config::addSetting(AbstractSetting* setting) {
-  _settings.emplace(setting->name, Config::SettingData(false, setting));
-  for (auto& alias : setting->aliases) {
-    _settings.emplace(alias, Config::SettingData(true, setting));
-  }
-
-  bool set = false;
-
-  auto i = unknownSettings.find(setting->name);
-  if (i != unknownSettings.end()) {
-    setting->set(i->second);
-    setting->overriden = true;
-    unknownSettings.erase(i);
-    set = true;
-  }
-
-  for (auto& alias : setting->aliases) {
-    auto i = unknownSettings.find(alias);
-    if (i != unknownSettings.end()) {
-      if (set) {
-        LOG(WARNING) << "setting '" << alias
-                     << "' is set, but it's an alias of '" << setting->name
-                     << "', which is also set";
-      }
-
-      else {
-        setting->set(i->second);
-        setting->overriden = true;
-        unknownSettings.erase(i);
-        set = true;
-      }
-    }
-  }
-}
-
-void AbstractConfig::warnUnknownSettings() {
-  for (auto& s : unknownSettings) {
-    LOG(WARNING) << "unknown setting: " << s.first;
-  }
-}
-
-void AbstractConfig::reapplyUnknownSettings() {
-  auto unknownSettings2 = std::move(unknownSettings);
-  for (auto& s : unknownSettings2) {
-    set(s.first, s.second);
-  }
-}
-
-void Config::getSettings(std::map<std::string, SettingInfo>& res,
-                         bool overridenOnly) {
-  for (auto& opt : _settings) {
-    if (!opt.second.isAlias &&
-        (!overridenOnly || opt.second.setting->overriden)) {
-      res.emplace(opt.first, SettingInfo{opt.second.setting->to_string(),
-                                         opt.second.setting->description});
-    }
-  }
-}
-
-void AbstractConfig::applyConfigFile(const Path& path) {
-  try {
-    std::string contents = readFile(path);
-
-    unsigned int pos = 0;
-
-    while (pos < contents.size()) {
-      std::string line;
-      while (pos < contents.size() && contents[pos] != '\n') {
-        line += contents[pos++];
-      }
-      pos++;
-
-      std::string::size_type hash = line.find('#');
-      if (hash != std::string::npos) {
-        line = std::string(line, 0, hash);
-      }
-
-      // TODO(tazjin): absl::string_view after path functions are fixed.
-      std::vector<std::string> tokens = absl::StrSplit(
-          line, absl::ByAnyChar(" \t\n\r"), absl::SkipWhitespace());
-      if (tokens.empty()) {
-        continue;
-      }
-
-      if (tokens.size() < 2) {
-        throw UsageError("illegal configuration line '%1%' in '%2%'", line,
-                         path);
-      }
-
-      auto include = false;
-      auto ignoreMissing = false;
-      if (tokens[0] == "include") {
-        include = true;
-      } else if (tokens[0] == "!include") {
-        include = true;
-        ignoreMissing = true;
-      }
-
-      if (include) {
-        if (tokens.size() != 2) {
-          throw UsageError("illegal configuration line '%1%' in '%2%'", line,
-                           path);
-        }
-        auto p = absPath(tokens[1], dirOf(path));
-        if (pathExists(p)) {
-          applyConfigFile(p);
-        } else if (!ignoreMissing) {
-          throw Error("file '%1%' included from '%2%' not found", p, path);
-        }
-        continue;
-      }
-
-      if (tokens[1] != "=") {
-        throw UsageError("illegal configuration line '%1%' in '%2%'", line,
-                         path);
-      }
-
-      std::string name = tokens[0];
-
-      auto i = tokens.begin();
-      advance(i, 2);
-
-      set(name,
-          concatStringsSep(" ", Strings(i, tokens.end())));  // FIXME: slow
-    };
-  } catch (SysError&) {
-  }
-}
-
-void Config::resetOverriden() {
-  for (auto& s : _settings) {
-    s.second.setting->overriden = false;
-  }
-}
-
-void Config::toJSON(JSONObject& out) {
-  for (auto& s : _settings) {
-    if (!s.second.isAlias) {
-      JSONObject out2(out.object(s.first));
-      out2.attr("description", s.second.setting->description);
-      JSONPlaceholder out3(out2.placeholder("value"));
-      s.second.setting->toJSON(out3);
-    }
-  }
-}
-
-void Config::convertToArgs(Args& args, const std::string& category) {
-  for (auto& s : _settings) {
-    if (!s.second.isAlias) {
-      s.second.setting->convertToArg(args, category);
-    }
-  }
-}
-
-AbstractSetting::AbstractSetting(std::string name, std::string description,
-                                 std::set<std::string> aliases)
-    : name(std::move(name)),
-      description(std::move(description)),
-      aliases(std::move(aliases)) {}
-
-void AbstractSetting::toJSON(JSONPlaceholder& out) { out.write(to_string()); }
-
-void AbstractSetting::convertToArg(Args& args, const std::string& category) {}
-
-template <typename T>
-void BaseSetting<T>::toJSON(JSONPlaceholder& out) {
-  out.write(value);
-}
-
-template <typename T>
-void BaseSetting<T>::convertToArg(Args& args, const std::string& category) {
-  args.mkFlag()
-      .longName(name)
-      .description(description)
-      .arity(1)
-      .handler([=](std::vector<std::string> ss) {
-        overriden = true;
-        set(ss[0]);
-      })
-      .category(category);
-}
-
-template <>
-void BaseSetting<std::string>::set(const std::string& str) {
-  value = str;
-}
-
-template <>
-std::string BaseSetting<std::string>::to_string() {
-  return value;
-}
-
-template <typename T>
-void BaseSetting<T>::set(const std::string& str) {
-  static_assert(std::is_integral<T>::value, "Integer required.");
-  if (!absl::SimpleAtoi(str, &value)) {
-    throw UsageError("setting '%s' has invalid value '%s'", name, str);
-  }
-}
-
-template <typename T>
-std::string BaseSetting<T>::to_string() {
-  static_assert(std::is_integral<T>::value, "Integer required.");
-  return std::to_string(value);
-}
-
-template <>
-void BaseSetting<bool>::set(const std::string& str) {
-  if (str == "true" || str == "yes" || str == "1") {
-    value = true;
-  } else if (str == "false" || str == "no" || str == "0") {
-    value = false;
-  } else {
-    throw UsageError("Boolean setting '%s' has invalid value '%s'", name, str);
-  }
-}
-
-template <>
-std::string BaseSetting<bool>::to_string() {
-  return value ? "true" : "false";
-}
-
-template <>
-void BaseSetting<bool>::convertToArg(Args& args, const std::string& category) {
-  args.mkFlag()
-      .longName(name)
-      .description(description)
-      .handler([=](const std::vector<std::string>& ss) { override(true); })
-      .category(category);
-  args.mkFlag()
-      .longName("no-" + name)
-      .description(description)
-      .handler([=](const std::vector<std::string>& ss) { override(false); })
-      .category(category);
-}
-
-template <>
-void BaseSetting<Strings>::set(const std::string& str) {
-  value = absl::StrSplit(str, absl::ByAnyChar(" \t\n\r"), absl::SkipEmpty());
-}
-
-template <>
-std::string BaseSetting<Strings>::to_string() {
-  return concatStringsSep(" ", value);
-}
-
-template <>
-void BaseSetting<Strings>::toJSON(JSONPlaceholder& out) {
-  JSONList list(out.list());
-  for (auto& s : value) {
-    list.elem(s);
-  }
-}
-
-template <>
-void BaseSetting<StringSet>::set(const std::string& str) {
-  value = absl::StrSplit(str, absl::ByAnyChar(" \t\n\r"), absl::SkipEmpty());
-}
-
-template <>
-std::string BaseSetting<StringSet>::to_string() {
-  return concatStringsSep(" ", value);
-}
-
-template <>
-void BaseSetting<StringSet>::toJSON(JSONPlaceholder& out) {
-  JSONList list(out.list());
-  for (auto& s : value) {
-    list.elem(s);
-  }
-}
-
-template class BaseSetting<int>;
-template class BaseSetting<unsigned int>;
-template class BaseSetting<long>;
-template class BaseSetting<unsigned long>;
-template class BaseSetting<long long>;
-template class BaseSetting<unsigned long long>;
-template class BaseSetting<bool>;
-template class BaseSetting<std::string>;
-template class BaseSetting<Strings>;
-template class BaseSetting<StringSet>;
-
-void PathSetting::set(const std::string& str) {
-  if (str.empty()) {
-    if (allowEmpty) {
-      value = "";
-    } else {
-      throw UsageError("setting '%s' cannot be empty", name);
-    }
-  } else {
-    value = canonPath(str);
-  }
-}
-
-bool GlobalConfig::set(const std::string& name, const std::string& value) {
-  for (auto& config : *configRegistrations) {
-    if (config->set(name, value)) {
-      return true;
-    }
-  }
-
-  unknownSettings.emplace(name, value);
-
-  return false;
-}
-
-void GlobalConfig::getSettings(std::map<std::string, SettingInfo>& res,
-                               bool overridenOnly) {
-  for (auto& config : *configRegistrations) {
-    config->getSettings(res, overridenOnly);
-  }
-}
-
-void GlobalConfig::resetOverriden() {
-  for (auto& config : *configRegistrations) {
-    config->resetOverriden();
-  }
-}
-
-void GlobalConfig::toJSON(JSONObject& out) {
-  for (auto& config : *configRegistrations) {
-    config->toJSON(out);
-  }
-}
-
-void GlobalConfig::convertToArgs(Args& args, const std::string& category) {
-  for (auto& config : *configRegistrations) {
-    config->convertToArgs(args, category);
-  }
-}
-
-GlobalConfig globalConfig;
-
-GlobalConfig::ConfigRegistrations* GlobalConfig::configRegistrations;
-
-GlobalConfig::Register::Register(Config* config) {
-  if (configRegistrations == nullptr) {
-    configRegistrations = new ConfigRegistrations;
-  }
-  configRegistrations->emplace_back(config);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/config.hh b/third_party/nix/src/libutil/config.hh
deleted file mode 100644
index 81b1c80e0e97..000000000000
--- a/third_party/nix/src/libutil/config.hh
+++ /dev/null
@@ -1,228 +0,0 @@
-#include <map>
-#include <set>
-
-#include "libutil/types.hh"
-
-#pragma once
-
-namespace nix {
-
-class Args;
-class AbstractSetting;
-class JSONPlaceholder;
-class JSONObject;
-
-class AbstractConfig {
- protected:
-  StringMap unknownSettings;
-
-  explicit AbstractConfig(const StringMap& initials = {})
-      : unknownSettings(initials) {}
-
- public:
-  virtual bool set(const std::string& name, const std::string& value) = 0;
-
-  struct SettingInfo {
-    std::string value;
-    std::string description;
-  };
-
-  virtual void getSettings(std::map<std::string, SettingInfo>& res,
-                           bool overridenOnly = false) = 0;
-
-  void applyConfigFile(const Path& path);
-
-  virtual void resetOverriden() = 0;
-
-  virtual void toJSON(JSONObject& out) = 0;
-
-  virtual void convertToArgs(Args& args, const std::string& category) = 0;
-
-  void warnUnknownSettings();
-
-  void reapplyUnknownSettings();
-};
-
-/* A class to simplify providing configuration settings. The typical
-   use is to inherit Config and add Setting<T> members:
-
-   class MyClass : private Config
-   {
-     Setting<int> foo{this, 123, "foo", "the number of foos to use"};
-     Setting<std::string> bar{this, "blabla", "bar", "the name of the bar"};
-
-     MyClass() : Config(readConfigFile("/etc/my-app.conf"))
-     {
-       std::cout << foo << "\n"; // will print 123 unless overriden
-     }
-   };
-*/
-
-class Config : public AbstractConfig {
-  friend class AbstractSetting;
-
- public:
-  struct SettingData {
-    bool isAlias;
-    AbstractSetting* setting;
-    SettingData(bool isAlias, AbstractSetting* setting)
-        : isAlias(isAlias), setting(setting) {}
-  };
-
-  typedef std::map<std::string, SettingData> Settings;
-
- private:
-  Settings _settings;
-
- public:
-  explicit Config(const StringMap& initials = {}) : AbstractConfig(initials) {}
-
-  bool set(const std::string& name, const std::string& value) override;
-
-  void addSetting(AbstractSetting* setting);
-
-  void getSettings(std::map<std::string, SettingInfo>& res,
-                   bool overridenOnly = false) override;
-
-  void resetOverriden() override;
-
-  void toJSON(JSONObject& out) override;
-
-  void convertToArgs(Args& args, const std::string& category) override;
-};
-
-class AbstractSetting {
-  friend class Config;
-
- public:
-  const std::string name;
-  const std::string description;
-  const std::set<std::string> aliases;
-
-  int created = 123;
-
-  bool overriden = false;
-
- protected:
-  AbstractSetting(std::string name, std::string description,
-                  std::set<std::string> aliases);
-
-  virtual ~AbstractSetting() {
-    // Check against a gcc miscompilation causing our constructor
-    // not to run (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431).
-    assert(created == 123);
-  }
-
-  virtual void set(const std::string& value) = 0;
-
-  virtual std::string to_string() = 0;
-
-  virtual void toJSON(JSONPlaceholder& out);
-
-  virtual void convertToArg(Args& args, const std::string& category);
-
-  bool isOverriden() { return overriden; }
-};
-
-/* A setting of type T. */
-template <typename T>
-class BaseSetting : public AbstractSetting {
- protected:
-  T value;
-
- public:
-  BaseSetting(const T& def, const std::string& name,
-              const std::string& description,
-              const std::set<std::string>& aliases = {})
-      : AbstractSetting(name, description, aliases), value(def) {}
-
-  operator const T&() const { return value; }
-  operator T&() { return value; }
-  const T& get() const { return value; }
-  bool operator==(const T& v2) const { return value == v2; }
-  bool operator!=(const T& v2) const { return value != v2; }
-  void operator=(const T& v) { assign(v); }
-  virtual void assign(const T& v) { value = v; }
-
-  void set(const std::string& str) override;
-
-  virtual void override(const T& v) {
-    overriden = true;
-    value = v;
-  }
-
-  std::string to_string() override;
-
-  void convertToArg(Args& args, const std::string& category) override;
-
-  void toJSON(JSONPlaceholder& out) override;
-};
-
-template <typename T>
-std::ostream& operator<<(std::ostream& str, const BaseSetting<T>& opt) {
-  str << (const T&)opt;
-  return str;
-}
-
-template <typename T>
-bool operator==(const T& v1, const BaseSetting<T>& v2) {
-  return v1 == (const T&)v2;
-}
-
-template <typename T>
-class Setting : public BaseSetting<T> {
- public:
-  Setting(Config* options, const T& def, const std::string& name,
-          const std::string& description,
-          const std::set<std::string>& aliases = {})
-      : BaseSetting<T>(def, name, description, aliases) {
-    options->addSetting(this);
-  }
-
-  void operator=(const T& v) { this->assign(v); }
-};
-
-/* A special setting for Paths. These are automatically canonicalised
-   (e.g. "/foo//bar/" becomes "/foo/bar"). */
-class PathSetting : public BaseSetting<Path> {
-  bool allowEmpty;
-
- public:
-  PathSetting(Config* options, bool allowEmpty, const Path& def,
-              const std::string& name, const std::string& description,
-              const std::set<std::string>& aliases = {})
-      : BaseSetting<Path>(def, name, description, aliases),
-        allowEmpty(allowEmpty) {
-    options->addSetting(this);
-  }
-
-  void set(const std::string& str) override;
-
-  Path operator+(const char* p) const { return value + p; }
-
-  void operator=(const Path& v) { this->assign(v); }
-};
-
-struct GlobalConfig : public AbstractConfig {
-  using ConfigRegistrations = std::vector<Config*>;
-  static ConfigRegistrations* configRegistrations;
-
-  bool set(const std::string& name, const std::string& value) override;
-
-  void getSettings(std::map<std::string, SettingInfo>& res,
-                   bool overridenOnly = false) override;
-
-  void resetOverriden() override;
-
-  void toJSON(JSONObject& out) override;
-
-  void convertToArgs(Args& args, const std::string& category) override;
-
-  struct Register {
-    explicit Register(Config* config);
-  };
-};
-
-extern GlobalConfig globalConfig;
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/finally.hh b/third_party/nix/src/libutil/finally.hh
deleted file mode 100644
index 2ead8661a6e7..000000000000
--- a/third_party/nix/src/libutil/finally.hh
+++ /dev/null
@@ -1,13 +0,0 @@
-#pragma once
-
-#include <functional>
-
-/* A trivial class to run a function at the end of a scope. */
-class Finally {
- private:
-  std::function<void()> fun;
-
- public:
-  explicit Finally(std::function<void()> fun) : fun(fun) {}
-  ~Finally() { fun(); }
-};
diff --git a/third_party/nix/src/libutil/hash.cc b/third_party/nix/src/libutil/hash.cc
deleted file mode 100644
index ba61254392e0..000000000000
--- a/third_party/nix/src/libutil/hash.cc
+++ /dev/null
@@ -1,484 +0,0 @@
-#include "libutil/hash.hh"
-
-#include <cstring>
-#include <iostream>
-
-#include <absl/strings/escaping.h>
-#include <absl/strings/str_format.h>
-#include <fcntl.h>
-#include <glog/logging.h>
-#include <openssl/md5.h>
-#include <openssl/sha.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#include "libutil/archive.hh"
-#include "libutil/istringstream_nocopy.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-std::optional<HashType> hash_type_from(nix::proto::HashType hash_type) {
-  switch (hash_type) {
-    case nix::proto::HashType::UNKNOWN:
-      return HashType::htUnknown;
-    case nix::proto::HashType::MD5:
-      return HashType::htMD5;
-    case nix::proto::HashType::SHA1:
-      return HashType::htSHA1;
-    case nix::proto::HashType::SHA256:
-      return HashType::htSHA256;
-    case nix::proto::HashType::SHA512:
-      return HashType::htSHA512;
-    default:
-      return {};
-  }
-}
-
-nix::proto::HashType HashTypeToProto(HashType hash_type) {
-  switch (hash_type) {
-    case HashType::htMD5:
-      return nix::proto::HashType::MD5;
-    case HashType::htSHA1:
-      return nix::proto::HashType::SHA1;
-    case HashType::htSHA256:
-      return nix::proto::HashType::SHA256;
-    case HashType::htSHA512:
-      return nix::proto::HashType::SHA512;
-    default:
-      return nix::proto::HashType::UNKNOWN;
-  }
-}
-
-void Hash::init() {
-  if (type == htMD5) {
-    hashSize = md5HashSize;
-  } else if (type == htSHA1) {
-    hashSize = sha1HashSize;
-  } else if (type == htSHA256) {
-    hashSize = sha256HashSize;
-  } else if (type == htSHA512) {
-    hashSize = sha512HashSize;
-  } else {
-    abort();
-  }
-  assert(hashSize <= maxHashSize);
-  memset(hash, 0, maxHashSize);
-}
-
-bool Hash::operator==(const Hash& h2) const {
-  if (hashSize != h2.hashSize) {
-    return false;
-  }
-  for (unsigned int i = 0; i < hashSize; i++) {
-    if (hash[i] != h2.hash[i]) {
-      return false;
-    }
-  }
-  return true;
-}
-
-bool Hash::operator!=(const Hash& h2) const { return !(*this == h2); }
-
-bool Hash::operator<(const Hash& h) const {
-  if (hashSize < h.hashSize) {
-    return true;
-  }
-  if (hashSize > h.hashSize) {
-    return false;
-  }
-  for (unsigned int i = 0; i < hashSize; i++) {
-    if (hash[i] < h.hash[i]) {
-      return true;
-    }
-    if (hash[i] > h.hash[i]) {
-      return false;
-    }
-  }
-  return false;
-}
-
-const std::string base16Chars = "0123456789abcdef";
-
-static std::string printHash16(const Hash& hash) {
-  char buf[hash.hashSize * 2];
-  for (unsigned int i = 0; i < hash.hashSize; i++) {
-    buf[i * 2] = base16Chars[hash.hash[i] >> 4];
-    buf[i * 2 + 1] = base16Chars[hash.hash[i] & 0x0f];
-  }
-  return std::string(buf, hash.hashSize * 2);
-}
-
-bool Hash::IsValidBase16(absl::string_view s) {
-  for (char c : s) {
-    if ('0' <= c && c <= '9') {
-      continue;
-    }
-    if ('a' <= c && c <= 'f') {
-      continue;
-    }
-    if ('A' <= c && c <= 'F') {
-      continue;
-    }
-    return false;
-  }
-  return true;
-}
-
-constexpr signed char kUnBase32[] = {
-    -1, -1, -1, -1, -1, -1, -1, -1, /* unprintables */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* unprintables */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* unprintables */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* unprintables */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* SP..' */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* (../ */
-    0,  1,  2,  3,  4,  5,  6,  7,  /* 0..7 */
-    8,  9,  -1, -1, -1, -1, -1, -1, /* 8..? */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* @..G */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* H..O */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* P..W */
-    -1, -1, -1, -1, -1, -1, -1, -1, /* X.._ */
-    -1, 10, 11, 12, 13, -1, 14, 15, /* `..g */
-    16, 17, 18, 19, 20, 21, 22, -1, /* h..o */
-    23, 24, 25, 26, -1, -1, 27, 28, /* p..w */
-    29, 30, 31, -1, -1, -1, -1, -1, /* x..DEL */
-
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* high */
-};
-
-bool Hash::IsValidBase32(absl::string_view s) {
-  static_assert(sizeof(kUnBase32) == 256);
-
-  for (char c : s) {
-    if (kUnBase32[static_cast<unsigned char>(c)] == -1) {
-      return false;
-    }
-  }
-  return true;
-}
-
-std::string Hash::ToStorePathHash() const {
-  return compressHash(*this, kStorePathHashSize).to_string(Base32, false);
-}
-
-static std::string printHash32(const Hash& hash) {
-  assert(hash.hashSize);
-  size_t len = hash.base32Len();
-  assert(len);
-
-  std::string s;
-  s.reserve(len);
-
-  for (int n = static_cast<int>(len) - 1; n >= 0; n--) {
-    unsigned int b = n * 5;
-    unsigned int i = b / 8;
-    unsigned int j = b % 8;
-    unsigned char c =
-        (hash.hash[i] >> j) |
-        (i >= hash.hashSize - 1 ? 0 : hash.hash[i + 1] << (8 - j));
-    s.push_back(base32Chars[c & 0x1f]);
-  }
-
-  return s;
-}
-
-std::string printHash16or32(const Hash& hash) {
-  return hash.to_string(hash.type == htMD5 ? Base16 : Base32, false);
-}
-
-std::string Hash::to_string(Base base, bool includeType) const {
-  std::string s;
-  if (base == SRI || includeType) {
-    s += printHashType(type);
-    s += base == SRI ? '-' : ':';
-  }
-  switch (base) {
-    case Base16:
-      s += printHash16(*this);
-      break;
-    case Base32:
-      s += printHash32(*this);
-      break;
-    case Base64:
-    case SRI:
-      std::string b64;
-      absl::Base64Escape(
-          std::string(reinterpret_cast<const char*>(hash), hashSize), &b64);
-      s += b64;
-      break;
-  }
-  return s;
-}
-
-Hash::Hash(std::string_view s, HashType type) : type(type) {
-  absl::StatusOr<Hash> result = deserialize(s, type);
-  *this = unwrap_throw(result);
-}
-
-// TODO(riking): change ht to an optional
-absl::StatusOr<Hash> Hash::deserialize(std::string_view s, HashType type) {
-  size_t pos = 0;
-  bool isSRI = false;
-
-  auto sep = s.find(':');
-  if (sep == std::string::npos) {
-    sep = s.find('-');
-    if (sep != std::string::npos) {
-      isSRI = true;
-    } else if (type == htUnknown) {
-      return absl::InvalidArgumentError(
-          absl::StrCat("hash string '", s, " does not include a type"));
-    }
-  }
-
-  HashType parsedType = type;
-  if (sep != std::string::npos) {
-    std::string hts = std::string(s, 0, sep);
-    parsedType = parseHashType(hts);
-    if (type != htUnknown && parsedType != type) {
-      return absl::InvalidArgumentError(
-          absl::StrCat("hash '", s, "' should have type '", printHashType(type),
-                       "', found '", printHashType(parsedType), "'"));
-    }
-    pos = sep + 1;
-  }
-
-  Hash dest(parsedType);
-
-  size_t size = s.size() - pos;
-  absl::string_view sv(s.data() + pos, size);
-
-  if (!isSRI && size == dest.base16Len()) {
-    std::string bytes;
-    if (!IsValidBase16(sv)) {
-      return absl::InvalidArgumentError(
-          absl::StrCat("invalid base-16 hash: bad character in '", s, "'"));
-    }
-    bytes = absl::HexStringToBytes(sv);
-    if (bytes.size() != dest.hashSize) {
-      return absl::InvalidArgumentError(
-          absl::StrCat("hash '", s, "' has wrong length for base16 ",
-                       printHashType(dest.type)));
-    }
-    memcpy(dest.hash, bytes.data(), dest.hashSize);
-  }
-
-  else if (!isSRI && size == dest.base32Len()) {
-    for (unsigned int n = 0; n < size; ++n) {
-      char c = sv[size - n - 1];
-      // range: -1, 0..31
-      signed char digit = kUnBase32[static_cast<unsigned char>(c)];
-      if (digit < 0) {
-        return absl::InvalidArgumentError(
-            absl::StrCat("invalid base-32 hash: bad character ",
-                         absl::CEscape(absl::string_view(&c, 1))));
-      }
-      unsigned int b = n * 5;
-      unsigned int i = b / 8;
-      unsigned int j = b % 8;
-      dest.hash[i] |= digit << j;
-
-      if (i < dest.hashSize - 1) {
-        dest.hash[i + 1] |= digit >> (8 - j);
-      } else {
-        if ((digit >> (8 - j)) != 0) {
-          return absl::InvalidArgumentError(
-              absl::StrCat("invalid base-32 hash '", s, "'"));
-        }
-      }
-    }
-  }
-
-  else if (isSRI || size == dest.base64Len()) {
-    std::string decoded;
-    if (!absl::Base64Unescape(sv, &decoded)) {
-      return absl::InvalidArgumentError("invalid base-64 hash");
-    }
-    if (decoded.size() != dest.hashSize) {
-      return absl::InvalidArgumentError(
-          absl::StrCat("hash '", s, "' has wrong length for base64 ",
-                       printHashType(dest.type)));
-    }
-    memcpy(dest.hash, decoded.data(), dest.hashSize);
-  }
-
-  else {
-    return absl::InvalidArgumentError(absl::StrCat(
-        "hash '", s, "' has wrong length for ", printHashType(dest.type)));
-  }
-
-  return dest;
-}
-
-Hash Hash::unwrap_throw(absl::StatusOr<Hash> hash) {
-  if (hash.ok()) {
-    return *hash;
-  } else {
-    throw BadHash(hash.status().message());
-  }
-}
-
-namespace hash {
-
-union Ctx {
-  MD5_CTX md5;
-  SHA_CTX sha1;
-  SHA256_CTX sha256;
-  SHA512_CTX sha512;
-};
-
-static void start(HashType ht, Ctx& ctx) {
-  if (ht == htMD5) {
-    MD5_Init(&ctx.md5);
-  } else if (ht == htSHA1) {
-    SHA1_Init(&ctx.sha1);
-  } else if (ht == htSHA256) {
-    SHA256_Init(&ctx.sha256);
-  } else if (ht == htSHA512) {
-    SHA512_Init(&ctx.sha512);
-  }
-}
-
-static void update(HashType ht, Ctx& ctx, const unsigned char* bytes,
-                   size_t len) {
-  if (ht == htMD5) {
-    MD5_Update(&ctx.md5, bytes, len);
-  } else if (ht == htSHA1) {
-    SHA1_Update(&ctx.sha1, bytes, len);
-  } else if (ht == htSHA256) {
-    SHA256_Update(&ctx.sha256, bytes, len);
-  } else if (ht == htSHA512) {
-    SHA512_Update(&ctx.sha512, bytes, len);
-  }
-}
-
-static void finish(HashType ht, Ctx& ctx, unsigned char* hash) {
-  if (ht == htMD5) {
-    MD5_Final(hash, &ctx.md5);
-  } else if (ht == htSHA1) {
-    SHA1_Final(hash, &ctx.sha1);
-  } else if (ht == htSHA256) {
-    SHA256_Final(hash, &ctx.sha256);
-  } else if (ht == htSHA512) {
-    SHA512_Final(hash, &ctx.sha512);
-  }
-}
-
-}  // namespace hash
-
-Hash hashString(HashType ht, const std::string& s) {
-  hash::Ctx ctx{};
-  Hash hash(ht);
-  start(ht, ctx);
-  update(ht, ctx, reinterpret_cast<const unsigned char*>(s.data()), s.length());
-  finish(ht, ctx, hash.hash);
-  return hash;
-}
-
-Hash hashFile(HashType ht, const Path& path) {
-  hash::Ctx ctx{};
-  Hash hash(ht);
-  start(ht, ctx);
-
-  AutoCloseFD fd(open(path.c_str(), O_RDONLY | O_CLOEXEC));
-  if (!fd) {
-    throw SysError(format("opening file '%1%'") % path);
-  }
-
-  std::vector<unsigned char> buf(8192);
-  ssize_t n;
-  while ((n = read(fd.get(), buf.data(), buf.size())) != 0) {
-    checkInterrupt();
-    if (n == -1) {
-      throw SysError(format("reading file '%1%'") % path);
-    }
-    update(ht, ctx, buf.data(), n);
-  }
-
-  finish(ht, ctx, hash.hash);
-  return hash;
-}
-
-HashSink::HashSink(HashType ht)
-    : ht(ht), ctx(std::make_unique<hash::Ctx>()), bytes(0) {
-  start(ht, *ctx);
-}
-
-HashSink::~HashSink() { bufPos = 0; }
-
-void HashSink::write(const unsigned char* data, size_t len) {
-  bytes += len;
-  nix::hash::update(ht, *ctx, data, len);
-}
-
-HashResult HashSink::finish() {
-  flush();
-  Hash hash(ht);
-  nix::hash::finish(ht, *ctx, hash.hash);
-  return HashResult(hash, bytes);
-}
-
-HashResult HashSink::currentHash() {
-  flush();
-  nix::hash::Ctx ctx2 = *ctx;
-  Hash hash(ht);
-  nix::hash::finish(ht, ctx2, hash.hash);
-  return HashResult(hash, bytes);
-}
-
-HashResult hashPath(HashType ht, const Path& path, PathFilter& filter) {
-  HashSink sink(ht);
-  dumpPath(path, sink, filter);
-  return sink.finish();
-}
-
-Hash compressHash(const Hash& hash, unsigned int newSize) {
-  Hash h;
-  h.hashSize = newSize;
-  for (unsigned int i = 0; i < hash.hashSize; ++i) {
-    h.hash[i % newSize] ^= hash.hash[i];
-  }
-  return h;
-}
-
-HashType parseHashType(const std::string& s) {
-  if (s == "md5") {
-    return htMD5;
-  }
-  if (s == "sha1") {
-    return htSHA1;
-  } else if (s == "sha256") {
-    return htSHA256;
-  } else if (s == "sha512") {
-    return htSHA512;
-  } else {
-    return htUnknown;
-  }
-}
-
-std::string printHashType(HashType ht) {
-  if (ht == htMD5) {
-    return "md5";
-  }
-  if (ht == htSHA1) {
-    return "sha1";
-  } else if (ht == htSHA256) {
-    return "sha256";
-  } else if (ht == htSHA512) {
-    return "sha512";
-  } else if (ht == htUnknown) {
-    return "<unknown>";
-  } else {
-    LOG(FATAL) << "Unrecognized hash type: " << static_cast<int>(ht);
-    abort();
-  }
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/hash.hh b/third_party/nix/src/libutil/hash.hh
deleted file mode 100644
index 8b52ac657e7f..000000000000
--- a/third_party/nix/src/libutil/hash.hh
+++ /dev/null
@@ -1,147 +0,0 @@
-#pragma once
-
-#include <absl/status/statusor.h>
-
-#include "libproto/worker.grpc.pb.h"
-#include "libutil/serialise.hh"
-#include "libutil/types.hh"
-
-namespace nix {
-
-// Size of the hashes rendered in store paths, in bytes
-constexpr unsigned int kStorePathHashSize = 20;
-
-MakeError(BadHash, Error);
-
-// TODO(grfn): Replace this with the hash type enum from the daemon proto so we
-// don't have to juggle two different types
-enum HashType : char { htUnknown, htMD5, htSHA1, htSHA256, htSHA512 };
-
-std::optional<HashType> hash_type_from(nix::proto::HashType hash_type);
-
-nix::proto::HashType HashTypeToProto(HashType hash_type);
-
-const int md5HashSize = 16;
-const int sha1HashSize = 20;
-const int sha256HashSize = 32;
-const int sha512HashSize = 64;
-
-// omitted: E O U T
-constexpr char base32Chars[] = "0123456789abcdfghijklmnpqrsvwxyz";
-
-enum Base : int { Base64, Base32, Base16, SRI };
-
-struct Hash {
-  static const unsigned int maxHashSize = 64;
-  unsigned int hashSize = 0;
-  unsigned char hash[maxHashSize] = {};
-
-  HashType type = htUnknown;
-
-  /* Create an unset hash object. */
-  Hash(){};
-
-  /* Create a zero-filled hash object. */
-  explicit Hash(HashType type) : type(type) { init(); };
-
-  /* Initialize the hash from a string representation, in the format
-     "[<type>:]<base16|base32|base64>" or "<type>-<base64>" (a
-     Subresource Integrity hash expression). If the 'type' argument
-     is htUnknown, then the hash type must be specified in the
-     string. */
-  explicit Hash(std::string_view s, HashType type = htUnknown);
-
-  /* Status-returning version of above constructor */
-  static absl::StatusOr<Hash> deserialize(std::string_view s,
-                                          HashType type = htUnknown);
-
-  // Legacy unwrapper for StatusOr. Throws BadHash.
-  static Hash unwrap_throw(absl::StatusOr<Hash> hash) noexcept(false);
-
-  void init();
-
-  /* Check whether a hash is set. */
-  explicit operator bool() const { return type != htUnknown; }
-
-  /* Check whether two hash are equal. */
-  bool operator==(const Hash& h2) const;
-
-  /* Check whether two hash are not equal. */
-  bool operator!=(const Hash& h2) const;
-
-  /* For sorting. */
-  bool operator<(const Hash& h) const;
-
-  /* Returns the length of a base-16 representation of this hash. */
-  size_t base16Len() const { return hashSize * 2; }
-
-  /* Returns the length of a base-32 representation of this hash. */
-  size_t base32Len() const { return (hashSize * 8 - 1) / 5 + 1; }
-
-  /* Returns the length of a base-64 representation of this hash. */
-  size_t base64Len() const { return ((4 * hashSize / 3) + 3) & ~3; }
-
-  /* Return a string representation of the hash, in base-16, base-32
-     or base-64. By default, this is prefixed by the hash type
-     (e.g. "sha256:"). */
-  std::string to_string(Base base = Base32, bool includeType = true) const;
-
-  /* Returns whether the passed string contains entirely valid base16
-     characters. */
-  static bool IsValidBase16(absl::string_view s);
-
-  /* Returns whether the passed string contains entirely valid base32
-     characters. */
-  static bool IsValidBase32(absl::string_view s);
-
-  // Convert this Hash to the format expected in store paths
-  [[nodiscard]] std::string ToStorePathHash() const;
-};
-
-/* Print a hash in base-16 if it's MD5, or base-32 otherwise. */
-std::string printHash16or32(const Hash& hash);
-
-/* Compute the hash of the given string. */
-Hash hashString(HashType ht, const std::string& s);
-
-/* Compute the hash of the given file. */
-Hash hashFile(HashType ht, const Path& path);
-
-/* A pair of the Hash, and the number of bytes consumed. */
-typedef std::pair<Hash, unsigned long long> HashResult;
-
-/* Compute the hash of the given path.  The hash is defined as
-   (essentially) hashString(ht, dumpPath(path)). */
-HashResult hashPath(HashType ht, const Path& path,
-                    PathFilter& filter = defaultPathFilter);
-
-/* Compress a hash to the specified number of bytes by cyclically
-   XORing bytes together. */
-Hash compressHash(const Hash& hash, unsigned int newSize);
-
-/* Parse a string representing a hash type. */
-HashType parseHashType(const std::string& s);
-
-/* And the reverse. */
-std::string printHashType(HashType ht);
-
-namespace hash {
-union Ctx;
-}
-
-class HashSink : public BufferedSink {
- private:
-  HashType ht;
-  std::unique_ptr<hash::Ctx> ctx;
-  unsigned long long bytes;
-
- public:
-  explicit HashSink(HashType ht);
-  HashSink(const HashSink& h);
-  ~HashSink();
-  void write(const unsigned char* data, size_t len);
-  HashResult finish();
-  HashResult currentHash();
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/istringstream_nocopy.hh b/third_party/nix/src/libutil/istringstream_nocopy.hh
deleted file mode 100644
index 31683d37c91b..000000000000
--- a/third_party/nix/src/libutil/istringstream_nocopy.hh
+++ /dev/null
@@ -1,85 +0,0 @@
-/* This file provides a variant of std::istringstream that doesn't
-   copy its string argument. This is useful for large strings. The
-   caller must ensure that the string object is not destroyed while
-   it's referenced by this object. */
-
-#pragma once
-
-#include <iostream>
-#include <string>
-
-template <class CharT, class Traits = std::char_traits<CharT>,
-          class Allocator = std::allocator<CharT>>
-class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> {
- public:
-  using string_type = std::basic_string<CharT, Traits, Allocator>;
-
-  using off_type = typename std::basic_streambuf<CharT, Traits>::off_type;
-
-  using pos_type = typename std::basic_streambuf<CharT, Traits>::pos_type;
-
-  using int_type = typename std::basic_streambuf<CharT, Traits>::int_type;
-
-  using traits_type = typename std::basic_streambuf<CharT, Traits>::traits_type;
-
- private:
-  const string_type& s;
-
-  off_type off;
-
- public:
-  explicit basic_istringbuf_nocopy(const string_type& s) : s{s}, off{0} {}
-
- private:
-  pos_type seekoff(off_type off, std::ios_base::seekdir dir,
-                   std::ios_base::openmode which) {
-    if (which & std::ios_base::in) {
-      this->off =
-          dir == std::ios_base::beg
-              ? off
-              : (dir == std::ios_base::end ? s.size() + off : this->off + off);
-    }
-    return pos_type(this->off);
-  }
-
-  pos_type seekpos(pos_type pos, std::ios_base::openmode which) {
-    return seekoff(pos, std::ios_base::beg, which);
-  }
-
-  std::streamsize showmanyc() { return s.size() - off; }
-
-  int_type underflow() {
-    if (typename string_type::size_type(off) == s.size()) {
-      return traits_type::eof();
-    }
-    return traits_type::to_int_type(s[off]);
-  }
-
-  int_type uflow() {
-    if (typename string_type::size_type(off) == s.size()) {
-      return traits_type::eof();
-    }
-    return traits_type::to_int_type(s[off++]);
-  }
-
-  int_type pbackfail(int_type ch) {
-    if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1])) {
-      return traits_type::eof();
-    }
-
-    return traits_type::to_int_type(s[--off]);
-  }
-};
-
-template <class CharT, class Traits = std::char_traits<CharT>,
-          class Allocator = std::allocator<CharT>>
-class basic_istringstream_nocopy : public std::basic_iostream<CharT, Traits> {
-  using buf_type = basic_istringbuf_nocopy<CharT, Traits, Allocator>;
-  buf_type buf;
-
- public:
-  explicit basic_istringstream_nocopy(const typename buf_type::string_type& s)
-      : std::basic_iostream<CharT, Traits>(&buf), buf(s){};
-};
-
-using istringstream_nocopy = basic_istringstream_nocopy<char>;
diff --git a/third_party/nix/src/libutil/json.cc b/third_party/nix/src/libutil/json.cc
deleted file mode 100644
index 59ff74f5796f..000000000000
--- a/third_party/nix/src/libutil/json.cc
+++ /dev/null
@@ -1,198 +0,0 @@
-#include "libutil/json.hh"
-
-#include <cstring>
-#include <iomanip>
-
-namespace nix {
-
-void toJSON(std::ostream& str, const char* start, const char* end) {
-  str << '"';
-  for (auto i = start; i != end; i++) {
-    if (*i == '\"' || *i == '\\') {
-      str << '\\' << *i;
-    } else if (*i == '\n') {
-      str << "\\n";
-    } else if (*i == '\r') {
-      str << "\\r";
-    } else if (*i == '\t') {
-      str << "\\t";
-    } else if (*i >= 0 && *i < 32) {
-      str << "\\u" << std::setfill('0') << std::setw(4) << std::hex
-          << static_cast<uint16_t>(*i) << std::dec;
-    } else {
-      str << *i;
-    }
-  }
-  str << '"';
-}
-
-void toJSON(std::ostream& str, const char* s) {
-  if (s == nullptr) {
-    str << "null";
-  } else {
-    toJSON(str, s, s + strlen(s));
-  }
-}
-
-template <>
-void toJSON<int>(std::ostream& str, const int& n) {
-  str << n;
-}
-template <>
-void toJSON<unsigned int>(std::ostream& str, const unsigned int& n) {
-  str << n;
-}
-template <>
-void toJSON<long>(std::ostream& str, const long& n) {
-  str << n;
-}
-template <>
-void toJSON<unsigned long>(std::ostream& str, const unsigned long& n) {
-  str << n;
-}
-template <>
-void toJSON<long long>(std::ostream& str, const long long& n) {
-  str << n;
-}
-template <>
-void toJSON<unsigned long long>(std::ostream& str,
-                                const unsigned long long& n) {
-  str << n;
-}
-template <>
-void toJSON<float>(std::ostream& str, const float& n) {
-  str << n;
-}
-template <>
-void toJSON<double>(std::ostream& str, const double& n) {
-  str << n;
-}
-
-template <>
-void toJSON<std::string>(std::ostream& str, const std::string& s) {
-  toJSON(str, s.c_str(), s.c_str() + s.size());
-}
-
-template <>
-void toJSON<bool>(std::ostream& str, const bool& b) {
-  str << (b ? "true" : "false");
-}
-
-template <>
-void toJSON<std::nullptr_t>(std::ostream& str, const std::nullptr_t& b) {
-  str << "null";
-}
-
-JSONWriter::JSONWriter(std::ostream& str, bool indent)
-    : state(new JSONState(str, indent)) {
-  state->stack++;
-}
-
-JSONWriter::JSONWriter(JSONState* state) : state(state) { state->stack++; }
-
-JSONWriter::~JSONWriter() {
-  if (state != nullptr) {
-    assertActive();
-    state->stack--;
-    if (state->stack == 0) {
-      delete state;
-    }
-  }
-}
-
-void JSONWriter::comma() {
-  assertActive();
-  if (first) {
-    first = false;
-  } else {
-    state->str << ',';
-  }
-  if (state->indent) {
-    indent();
-  }
-}
-
-void JSONWriter::indent() {
-  state->str << '\n' << std::string(state->depth * 2, ' ');
-}
-
-void JSONList::open() {
-  state->depth++;
-  state->str << '[';
-}
-
-JSONList::~JSONList() {
-  state->depth--;
-  if (state->indent && !first) {
-    indent();
-  }
-  state->str << "]";
-}
-
-JSONList JSONList::list() {
-  comma();
-  return JSONList(state);
-}
-
-JSONObject JSONList::object() {
-  comma();
-  return JSONObject(state);
-}
-
-JSONPlaceholder JSONList::placeholder() {
-  comma();
-  return JSONPlaceholder(state);
-}
-
-void JSONObject::open() {
-  state->depth++;
-  state->str << '{';
-}
-
-JSONObject::~JSONObject() {
-  if (state != nullptr) {
-    state->depth--;
-    if (state->indent && !first) {
-      indent();
-    }
-    state->str << "}";
-  }
-}
-
-void JSONObject::attr(const std::string& s) {
-  comma();
-  toJSON(state->str, s);
-  state->str << ':';
-  if (state->indent) {
-    state->str << ' ';
-  }
-}
-
-JSONList JSONObject::list(const std::string& name) {
-  attr(name);
-  return JSONList(state);
-}
-
-JSONObject JSONObject::object(const std::string& name) {
-  attr(name);
-  return JSONObject(state);
-}
-
-JSONPlaceholder JSONObject::placeholder(const std::string& name) {
-  attr(name);
-  return JSONPlaceholder(state);
-}
-
-JSONList JSONPlaceholder::list() {
-  assertValid();
-  first = false;
-  return JSONList(state);
-}
-
-JSONObject JSONPlaceholder::object() {
-  assertValid();
-  first = false;
-  return JSONObject(state);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/json.hh b/third_party/nix/src/libutil/json.hh
deleted file mode 100644
index 14d61d8a5716..000000000000
--- a/third_party/nix/src/libutil/json.hh
+++ /dev/null
@@ -1,144 +0,0 @@
-#pragma once
-
-#include <cassert>
-#include <iostream>
-#include <vector>
-
-namespace nix {
-
-void toJSON(std::ostream& str, const char* start, const char* end);
-void toJSON(std::ostream& str, const char* s);
-
-template <typename T>
-void toJSON(std::ostream& str, const T& n);
-
-class JSONWriter {
- protected:
-  struct JSONState {
-    std::ostream& str;
-    bool indent;
-    size_t depth = 0;
-    size_t stack = 0;
-    JSONState(std::ostream& str, bool indent) : str(str), indent(indent) {}
-    ~JSONState() { assert(stack == 0); }
-  };
-
-  JSONState* state;
-
-  bool first = true;
-
-  JSONWriter(std::ostream& str, bool indent);
-
-  explicit JSONWriter(JSONState* state);
-
-  ~JSONWriter();
-
-  void assertActive() { assert(state->stack != 0); }
-
-  void comma();
-
-  void indent();
-};
-
-class JSONObject;
-class JSONPlaceholder;
-
-class JSONList : JSONWriter {
- private:
-  friend class JSONObject;
-  friend class JSONPlaceholder;
-
-  void open();
-
-  explicit JSONList(JSONState* state) : JSONWriter(state) { open(); }
-
- public:
-  explicit JSONList(std::ostream& str, bool indent = false)
-      : JSONWriter(str, indent) {
-    open();
-  }
-
-  ~JSONList();
-
-  template <typename T>
-  JSONList& elem(const T& v) {
-    comma();
-    toJSON(state->str, v);
-    return *this;
-  }
-
-  JSONList list();
-
-  JSONObject object();
-
-  JSONPlaceholder placeholder();
-};
-
-class JSONObject : JSONWriter {
- private:
-  friend class JSONList;
-  friend class JSONPlaceholder;
-
-  void open();
-
-  explicit JSONObject(JSONState* state) : JSONWriter(state) { open(); }
-
-  void attr(const std::string& s);
-
- public:
-  explicit JSONObject(std::ostream& str, bool indent = false)
-      : JSONWriter(str, indent) {
-    open();
-  }
-
-  JSONObject(const JSONObject& obj) = delete;
-
-  JSONObject(JSONObject&& obj) : JSONWriter(obj.state) { obj.state = 0; }
-
-  ~JSONObject();
-
-  template <typename T>
-  JSONObject& attr(const std::string& name, const T& v) {
-    attr(name);
-    toJSON(state->str, v);
-    return *this;
-  }
-
-  JSONList list(const std::string& name);
-
-  JSONObject object(const std::string& name);
-
-  JSONPlaceholder placeholder(const std::string& name);
-};
-
-class JSONPlaceholder : JSONWriter {
- private:
-  friend class JSONList;
-  friend class JSONObject;
-
-  explicit JSONPlaceholder(JSONState* state) : JSONWriter(state) {}
-
-  void assertValid() {
-    assertActive();
-    assert(first);
-  }
-
- public:
-  explicit JSONPlaceholder(std::ostream& str, bool indent = false)
-      : JSONWriter(str, indent) {}
-
-  ~JSONPlaceholder() { assert(!first || std::uncaught_exception()); }
-
-  template <typename T>
-  void write(const T& v) {
-    assertValid();
-    first = false;
-    toJSON(state->str, v);
-  }
-
-  JSONList list();
-
-  JSONObject object();
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/lazy.hh b/third_party/nix/src/libutil/lazy.hh
deleted file mode 100644
index 5c6ff5d8df6a..000000000000
--- a/third_party/nix/src/libutil/lazy.hh
+++ /dev/null
@@ -1,45 +0,0 @@
-#include <exception>
-#include <functional>
-#include <mutex>
-
-namespace nix {
-
-/* A helper class for lazily-initialized variables.
-
-     Lazy<T> var([]() { return value; });
-
-   declares a variable of type T that is initialized to 'value' (in a
-   thread-safe way) on first use, that is, when var() is first
-   called. If the initialiser code throws an exception, then all
-   subsequent calls to var() will rethrow that exception. */
-template <typename T>
-class Lazy {
-  typedef std::function<T()> Init;
-
-  Init init;
-
-  std::once_flag done;
-
-  T value;
-
-  std::exception_ptr ex;
-
- public:
-  explicit Lazy(Init init) : init(init) {}
-
-  const T& operator()() {
-    std::call_once(done, [&]() {
-      try {
-        value = init();
-      } catch (...) {
-        ex = std::current_exception();
-      }
-    });
-    if (ex) {
-      std::rethrow_exception(ex);
-    }
-    return value;
-  }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/lru-cache.hh b/third_party/nix/src/libutil/lru-cache.hh
deleted file mode 100644
index 1832c542449e..000000000000
--- a/third_party/nix/src/libutil/lru-cache.hh
+++ /dev/null
@@ -1,90 +0,0 @@
-#pragma once
-
-#include <list>
-#include <map>
-#include <optional>
-
-namespace nix {
-
-/* A simple least-recently used cache. Not thread-safe. */
-template <typename Key, typename Value>
-class LRUCache {
- private:
-  size_t capacity;
-
-  // Stupid wrapper to get around circular dependency between Data
-  // and LRU.
-  struct LRUIterator;
-
-  using Data = std::map<Key, std::pair<LRUIterator, Value>>;
-  using LRU = std::list<typename Data::iterator>;
-
-  struct LRUIterator {
-    typename LRU::iterator it;
-  };
-
-  Data data;
-  LRU lru;
-
- public:
-  explicit LRUCache(size_t capacity) : capacity(capacity) {}
-
-  /* Insert or upsert an item in the cache. */
-  void upsert(const Key& key, const Value& value) {
-    if (capacity == 0) {
-      return;
-    }
-
-    erase(key);
-
-    if (data.size() >= capacity) {
-      /* Retire the oldest item. */
-      auto oldest = lru.begin();
-      data.erase(*oldest);
-      lru.erase(oldest);
-    }
-
-    auto res = data.emplace(key, std::make_pair(LRUIterator(), value));
-    assert(res.second);
-    auto& i(res.first);
-
-    auto j = lru.insert(lru.end(), i);
-
-    i->second.first.it = j;
-  }
-
-  bool erase(const Key& key) {
-    auto i = data.find(key);
-    if (i == data.end()) {
-      return false;
-    }
-    lru.erase(i->second.first.it);
-    data.erase(i);
-    return true;
-  }
-
-  /* Look up an item in the cache. If it exists, it becomes the most
-     recently used item. */
-  std::optional<Value> get(const Key& key) {
-    auto i = data.find(key);
-    if (i == data.end()) {
-      return {};
-    }
-
-    /* Move this item to the back of the LRU list. */
-    lru.erase(i->second.first.it);
-    auto j = lru.insert(lru.end(), i);
-    i->second.first.it = j;
-
-    return i->second.second;
-  }
-
-  size_t size() { return data.size(); }
-
-  void clear() {
-    data.clear();
-    lru.clear();
-  }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/monitor-fd.hh b/third_party/nix/src/libutil/monitor-fd.hh
deleted file mode 100644
index c818c5826116..000000000000
--- a/third_party/nix/src/libutil/monitor-fd.hh
+++ /dev/null
@@ -1,57 +0,0 @@
-#pragma once
-
-#include <atomic>
-#include <cstdlib>
-#include <thread>
-
-#include <poll.h>
-#include <signal.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-namespace nix {
-
-class MonitorFdHup {
- private:
-  std::thread thread;
-
- public:
-  MonitorFdHup(int fd) {
-    thread = std::thread([fd]() {
-      while (true) {
-        /* Wait indefinitely until a POLLHUP occurs. */
-        struct pollfd fds[1];
-        fds[0].fd = fd;
-        /* This shouldn't be necessary, but macOS doesn't seem to
-           like a zeroed out events field.
-           See rdar://37537852.
-        */
-        fds[0].events = POLLHUP;
-        auto count = poll(fds, 1, -1);
-        if (count == -1) {
-          abort();
-        }  // can't happen
-        /* This shouldn't happen, but can on macOS due to a bug.
-           See rdar://37550628.
-
-           This may eventually need a delay or further
-           coordination with the main thread if spinning proves
-           too harmful.
-         */
-        if (count == 0) {
-          continue;
-        }
-        assert(fds[0].revents & POLLHUP);
-        triggerInterrupt();
-        break;
-      }
-    });
-  };
-
-  ~MonitorFdHup() {
-    pthread_cancel(thread.native_handle());
-    thread.join();
-  }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/pool.hh b/third_party/nix/src/libutil/pool.hh
deleted file mode 100644
index b5c3c4b5c43f..000000000000
--- a/third_party/nix/src/libutil/pool.hh
+++ /dev/null
@@ -1,176 +0,0 @@
-#pragma once
-
-#include <cassert>
-#include <functional>
-#include <limits>
-#include <list>
-#include <memory>
-
-#include "libutil/ref.hh"
-#include "libutil/sync.hh"
-
-namespace nix {
-
-/* This template class implements a simple pool manager of resources
-   of some type R, such as database connections. It is used as
-   follows:
-
-     class Connection { ... };
-
-     Pool<Connection> pool;
-
-     {
-       auto conn(pool.get());
-       conn->exec("select ...");
-     }
-
-   Here, the Connection object referenced by ‘conn’ is automatically
-   returned to the pool when ‘conn’ goes out of scope.
-*/
-
-template <class R>
-class Pool {
- public:
-  /* A function that produces new instances of R on demand. */
-  typedef std::function<ref<R>()> Factory;
-
-  /* A function that checks whether an instance of R is still
-     usable. Unusable instances are removed from the pool. */
-  using Validator = std::function<bool(const ref<R>&)>;
-
- private:
-  Factory factory;
-  Validator validator;
-
-  struct State {
-    size_t inUse = 0;
-    size_t max;
-    std::vector<ref<R>> idle;
-  };
-
-  Sync<State> state;
-
-  std::condition_variable wakeup;
-
- public:
-  explicit Pool(
-      size_t max = std::numeric_limits<size_t>::max(),
-      const Factory& factory = []() { return make_ref<R>(); },
-      const Validator& validator = [](ref<R> r) { return true; })
-      : factory(factory), validator(validator) {
-    auto state_(state.lock());
-    state_->max = max;
-  }
-
-  void incCapacity() {
-    auto state_(state.lock());
-    state_->max++;
-    /* we could wakeup here, but this is only used when we're
-     * about to nest Pool usages, and we want to save the slot for
-     * the nested use if we can
-     */
-  }
-
-  void decCapacity() {
-    auto state_(state.lock());
-    state_->max--;
-  }
-
-  ~Pool() {
-    auto state_(state.lock());
-    assert(!state_->inUse);
-    state_->max = 0;
-    state_->idle.clear();
-  }
-
-  class Handle {
-   private:
-    Pool& pool;
-    std::shared_ptr<R> r;
-    bool bad = false;
-
-    friend Pool;
-
-    Handle(Pool& pool, std::shared_ptr<R> r) : pool(pool), r(r) {}
-
-   public:
-    Handle(Handle&& h) : pool(h.pool), r(h.r) { h.r.reset(); }
-
-    Handle(const Handle& l) = delete;
-
-    ~Handle() {
-      if (!r) {
-        return;
-      }
-      {
-        auto state_(pool.state.lock());
-        if (!bad) {
-          state_->idle.push_back(ref<R>(r));
-        }
-        assert(state_->inUse);
-        state_->inUse--;
-      }
-      pool.wakeup.notify_one();
-    }
-
-    R* operator->() { return &*r; }
-    R& operator*() { return *r; }
-
-    void markBad() { bad = true; }
-  };
-
-  Handle get() {
-    {
-      auto state_(state.lock());
-
-      /* If we're over the maximum number of instance, we need
-         to wait until a slot becomes available. */
-      while (state_->idle.empty() && state_->inUse >= state_->max) {
-        state_.wait(wakeup);
-      }
-
-      while (!state_->idle.empty()) {
-        auto p = state_->idle.back();
-        state_->idle.pop_back();
-        if (validator(p)) {
-          state_->inUse++;
-          return Handle(*this, p);
-        }
-      }
-
-      state_->inUse++;
-    }
-
-    /* We need to create a new instance. Because that might take a
-       while, we don't hold the lock in the meantime. */
-    try {
-      Handle h(*this, factory());
-      return h;
-    } catch (...) {
-      auto state_(state.lock());
-      state_->inUse--;
-      wakeup.notify_one();
-      throw;
-    }
-  }
-
-  size_t count() {
-    auto state_(state.lock());
-    return state_->idle.size() + state_->inUse;
-  }
-
-  size_t capacity() { return state.lock()->max; }
-
-  void flushBad() {
-    auto state_(state.lock());
-    std::vector<ref<R>> left;
-    for (auto& p : state_->idle) {
-      if (validator(p)) {
-        left.push_back(p);
-      }
-    }
-    std::swap(state_->idle, left);
-  }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/proto.hh b/third_party/nix/src/libutil/proto.hh
deleted file mode 100644
index 058cb7b7b452..000000000000
--- a/third_party/nix/src/libutil/proto.hh
+++ /dev/null
@@ -1,174 +0,0 @@
-#pragma once
-
-#include <absl/status/status.h>
-#include <grpcpp/impl/codegen/status.h>
-#include <grpcpp/impl/codegen/status_code_enum.h>
-
-#include "libproto/worker.pb.h"
-#include "libutil/types.hh"
-
-namespace nix::util::proto {
-
-inline ::nix::proto::StorePath StorePath(const Path& path) {
-  ::nix::proto::StorePath store_path;
-  store_path.set_path(path);
-  return store_path;
-}
-
-inline ::nix::proto::StorePaths StorePaths(const PathSet& paths) {
-  ::nix::proto::StorePaths result;
-  for (const auto& path : paths) {
-    result.add_paths(path);
-  }
-  return result;
-}
-
-template <typename T, typename U>
-T FillFrom(const U& src) {
-  T result;
-  result.insert(src.begin(), src.end());
-  return result;
-}
-
-constexpr absl::StatusCode GRPCStatusCodeToAbsl(grpc::StatusCode code) {
-  switch (code) {
-    case grpc::StatusCode::OK:
-      return absl::StatusCode::kOk;
-    case grpc::StatusCode::CANCELLED:
-      return absl::StatusCode::kCancelled;
-    case grpc::StatusCode::UNKNOWN:
-      return absl::StatusCode::kUnknown;
-    case grpc::StatusCode::INVALID_ARGUMENT:
-      return absl::StatusCode::kInvalidArgument;
-    case grpc::StatusCode::DEADLINE_EXCEEDED:
-      return absl::StatusCode::kDeadlineExceeded;
-    case grpc::StatusCode::NOT_FOUND:
-      return absl::StatusCode::kNotFound;
-    case grpc::StatusCode::ALREADY_EXISTS:
-      return absl::StatusCode::kAlreadyExists;
-    case grpc::StatusCode::PERMISSION_DENIED:
-      return absl::StatusCode::kPermissionDenied;
-    case grpc::StatusCode::UNAUTHENTICATED:
-      return absl::StatusCode::kUnauthenticated;
-    case grpc::StatusCode::RESOURCE_EXHAUSTED:
-      return absl::StatusCode::kResourceExhausted;
-    case grpc::StatusCode::FAILED_PRECONDITION:
-      return absl::StatusCode::kFailedPrecondition;
-    case grpc::StatusCode::ABORTED:
-      return absl::StatusCode::kAborted;
-    case grpc::StatusCode::OUT_OF_RANGE:
-      return absl::StatusCode::kOutOfRange;
-    case grpc::StatusCode::UNIMPLEMENTED:
-      return absl::StatusCode::kUnimplemented;
-    case grpc::StatusCode::INTERNAL:
-      return absl::StatusCode::kInternal;
-    case grpc::StatusCode::UNAVAILABLE:
-      return absl::StatusCode::kUnavailable;
-    case grpc::StatusCode::DATA_LOSS:
-      return absl::StatusCode::kDataLoss;
-    default:
-      return absl::StatusCode::kInternal;
-  }
-}
-
-constexpr grpc::StatusCode AbslStatusCodeToGRPC(absl::StatusCode code) {
-  switch (code) {
-    case absl::StatusCode::kOk:
-      return grpc::StatusCode::OK;
-    case absl::StatusCode::kCancelled:
-      return grpc::StatusCode::CANCELLED;
-    case absl::StatusCode::kUnknown:
-      return grpc::StatusCode::UNKNOWN;
-    case absl::StatusCode::kInvalidArgument:
-      return grpc::StatusCode::INVALID_ARGUMENT;
-    case absl::StatusCode::kDeadlineExceeded:
-      return grpc::StatusCode::DEADLINE_EXCEEDED;
-    case absl::StatusCode::kNotFound:
-      return grpc::StatusCode::NOT_FOUND;
-    case absl::StatusCode::kAlreadyExists:
-      return grpc::StatusCode::ALREADY_EXISTS;
-    case absl::StatusCode::kPermissionDenied:
-      return grpc::StatusCode::PERMISSION_DENIED;
-    case absl::StatusCode::kUnauthenticated:
-      return grpc::StatusCode::UNAUTHENTICATED;
-    case absl::StatusCode::kResourceExhausted:
-      return grpc::StatusCode::RESOURCE_EXHAUSTED;
-    case absl::StatusCode::kFailedPrecondition:
-      return grpc::StatusCode::FAILED_PRECONDITION;
-    case absl::StatusCode::kAborted:
-      return grpc::StatusCode::ABORTED;
-    case absl::StatusCode::kOutOfRange:
-      return grpc::StatusCode::OUT_OF_RANGE;
-    case absl::StatusCode::kUnimplemented:
-      return grpc::StatusCode::UNIMPLEMENTED;
-    case absl::StatusCode::kInternal:
-      return grpc::StatusCode::INTERNAL;
-    case absl::StatusCode::kUnavailable:
-      return grpc::StatusCode::UNAVAILABLE;
-    case absl::StatusCode::kDataLoss:
-      return grpc::StatusCode::DATA_LOSS;
-    default:
-      return grpc::StatusCode::INTERNAL;
-  }
-}
-
-constexpr absl::string_view GRPCStatusCodeDescription(grpc::StatusCode code) {
-  switch (code) {
-    case grpc::StatusCode::OK:
-      return "OK";
-    case grpc::StatusCode::CANCELLED:
-      return "CANCELLED";
-    case grpc::StatusCode::UNKNOWN:
-      return "UNKNOWN";
-    case grpc::StatusCode::INVALID_ARGUMENT:
-      return "INVALID_ARGUMENT";
-    case grpc::StatusCode::DEADLINE_EXCEEDED:
-      return "DEADLINE_EXCEEDED";
-    case grpc::StatusCode::NOT_FOUND:
-      return "NOT_FOUND";
-    case grpc::StatusCode::ALREADY_EXISTS:
-      return "ALREADY_EXISTS";
-    case grpc::StatusCode::PERMISSION_DENIED:
-      return "PERMISSION_DENIED";
-    case grpc::StatusCode::UNAUTHENTICATED:
-      return "UNAUTHENTICATED";
-    case grpc::StatusCode::RESOURCE_EXHAUSTED:
-      return "RESOURCE_EXHAUSTED";
-    case grpc::StatusCode::FAILED_PRECONDITION:
-      return "FAILED_PRECONDITION";
-    case grpc::StatusCode::ABORTED:
-      return "ABORTED";
-    case grpc::StatusCode::OUT_OF_RANGE:
-      return "OUT_OF_RANGE";
-    case grpc::StatusCode::UNIMPLEMENTED:
-      return "UNIMPLEMENTED";
-    case grpc::StatusCode::INTERNAL:
-      return "INTERNAL";
-    case grpc::StatusCode::UNAVAILABLE:
-      return "UNAVAILABLE";
-    case grpc::StatusCode::DATA_LOSS:
-      return "DATA_LOSS";
-    default:
-      return "<BAD ERROR CODE>";
-  };
-}
-
-inline absl::Status GRPCStatusToAbsl(grpc::Status status) {
-  if (status.ok()) {
-    return absl::OkStatus();
-  }
-
-  return absl::Status(GRPCStatusCodeToAbsl(status.error_code()),
-                      status.error_message());
-}
-
-inline grpc::Status AbslToGRPCStatus(absl::Status status) {
-  if (status.ok()) {
-    return grpc::Status::OK;
-  }
-
-  return grpc::Status(AbslStatusCodeToGRPC(status.code()),
-                      std::string(status.message()));
-}
-
-}  // namespace nix::util::proto
diff --git a/third_party/nix/src/libutil/ref.hh b/third_party/nix/src/libutil/ref.hh
deleted file mode 100644
index 3c375491fd0b..000000000000
--- a/third_party/nix/src/libutil/ref.hh
+++ /dev/null
@@ -1,65 +0,0 @@
-#pragma once
-
-#include <exception>
-#include <memory>
-#include <stdexcept>
-
-namespace nix {
-
-/* A simple non-nullable reference-counted pointer. Actually a wrapper
-   around std::shared_ptr that prevents non-null constructions. */
-template <typename T>
-class ref {  // TODO(tazjin): rename to brainworm_ref or something
- private:
-  std::shared_ptr<T> p;
-
- public:
-  ref<T>(const ref<T>& r) : p(r.p) {}
-
-  explicit ref<T>(const std::shared_ptr<T>& p) : p(p) {
-    if (!p) {
-      throw std::invalid_argument("null pointer cast to ref");
-    }
-  }
-
-  explicit ref<T>(T* p) : p(p) {
-    if (!p) {
-      throw std::invalid_argument("null pointer cast to ref");
-    }
-  }
-
-  T* operator->() const { return &*p; }
-
-  T& operator*() const { return *p; }
-
-  operator std::shared_ptr<T>() const { return p; }
-
-  std::shared_ptr<T> get_ptr() const { return p; }
-
-  template <typename T2>
-  ref<T2> cast() const {
-    return ref<T2>(std::dynamic_pointer_cast<T2>(p));
-  }
-
-  template <typename T2>
-  std::shared_ptr<T2> dynamic_pointer_cast() const {
-    return std::dynamic_pointer_cast<T2>(p);
-  }
-
-  template <typename T2>
-  operator ref<T2>() const {
-    return ref<T2>((std::shared_ptr<T2>)p);
-  }
-
- private:
-  template <typename T2, typename... Args>
-  friend ref<T2> make_ref(Args&&... args);
-};
-
-template <typename T, typename... Args>
-inline ref<T> make_ref(Args&&... args) {
-  auto p = std::make_shared<T>(std::forward<Args>(args)...);
-  return ref<T>(p);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/serialise.cc b/third_party/nix/src/libutil/serialise.cc
deleted file mode 100644
index 288255089bb6..000000000000
--- a/third_party/nix/src/libutil/serialise.cc
+++ /dev/null
@@ -1,311 +0,0 @@
-#include "libutil/serialise.hh"
-
-#include <boost/coroutine2/coroutine.hpp>
-#include <cerrno>
-#include <cstring>
-#include <memory>
-#include <utility>
-
-#include <glog/logging.h>
-
-#include "libutil/util.hh"
-
-namespace nix {
-
-void BufferedSink::operator()(const unsigned char* data, size_t len) {
-  if (!buffer) {
-    buffer = decltype(buffer)(new unsigned char[bufSize]);
-  }
-
-  while (len != 0u) {
-    /* Optimisation: bypass the buffer if the data exceeds the
-       buffer size. */
-    if (bufPos + len >= bufSize) {
-      flush();
-      write(data, len);
-      break;
-    }
-    /* Otherwise, copy the bytes to the buffer.  Flush the buffer
-       when it's full. */
-    size_t n = bufPos + len > bufSize ? bufSize - bufPos : len;
-    memcpy(buffer.get() + bufPos, data, n);
-    data += n;
-    bufPos += n;
-    len -= n;
-    if (bufPos == bufSize) {
-      flush();
-    }
-  }
-}
-
-void BufferedSink::flush() {
-  if (bufPos == 0) {
-    return;
-  }
-  size_t n = bufPos;
-  bufPos = 0;  // don't trigger the assert() in ~BufferedSink()
-  write(buffer.get(), n);
-}
-
-FdSink::~FdSink() {
-  try {
-    flush();
-  } catch (...) {
-    ignoreException();
-  }
-}
-
-size_t threshold = 256 * 1024 * 1024;
-
-static void warnLargeDump() {
-  LOG(WARNING)
-      << "dumping very large path (> 256 MiB); this may run out of memory";
-}
-
-void FdSink::write(const unsigned char* data, size_t len) {
-  written += len;
-  static bool warned = false;
-  if (warn && !warned) {
-    if (written > threshold) {
-      warnLargeDump();
-      warned = true;
-    }
-  }
-  try {
-    writeFull(fd, data, len);
-  } catch (SysError& e) {
-    _good = false;
-    throw;
-  }
-}
-
-bool FdSink::good() { return _good; }
-
-void Source::operator()(unsigned char* data, size_t len) {
-  while (len != 0u) {
-    size_t n = read(data, len);
-    data += n;
-    len -= n;
-  }
-}
-
-std::string Source::drain() {
-  std::string s;
-  std::vector<unsigned char> buf(8192);
-  while (true) {
-    size_t n;
-    try {
-      n = read(buf.data(), buf.size());
-      s.append(reinterpret_cast<char*>(buf.data()), n);
-    } catch (EndOfFile&) {
-      break;
-    }
-  }
-  return s;
-}
-
-size_t BufferedSource::read(unsigned char* data, size_t len) {
-  if (!buffer) {
-    buffer = decltype(buffer)(new unsigned char[bufSize]);
-  }
-
-  if (bufPosIn == 0u) {
-    bufPosIn = readUnbuffered(buffer.get(), bufSize);
-  }
-
-  /* Copy out the data in the buffer. */
-  size_t n = len > bufPosIn - bufPosOut ? bufPosIn - bufPosOut : len;
-  memcpy(data, buffer.get() + bufPosOut, n);
-  bufPosOut += n;
-  if (bufPosIn == bufPosOut) {
-    bufPosIn = bufPosOut = 0;
-  }
-  return n;
-}
-
-bool BufferedSource::hasData() { return bufPosOut < bufPosIn; }
-
-size_t FdSource::readUnbuffered(unsigned char* data, size_t len) {
-  ssize_t n;
-  do {
-    checkInterrupt();
-    n = ::read(fd, reinterpret_cast<char*>(data), len);
-  } while (n == -1 && errno == EINTR);
-  if (n == -1) {
-    _good = false;
-    throw SysError("reading from file");
-  }
-  if (n == 0) {
-    _good = false;
-    throw EndOfFile("unexpected end-of-file");
-  }
-  read += n;
-  return n;
-}
-
-bool FdSource::good() { return _good; }
-
-size_t StringSource::read(unsigned char* data, size_t len) {
-  if (pos == s.size()) {
-    throw EndOfFile("end of string reached");
-  }
-  size_t n = s.copy(reinterpret_cast<char*>(data), len, pos);
-  pos += n;
-  return n;
-}
-
-#if BOOST_VERSION >= 106300 && BOOST_VERSION < 106600
-#error Coroutines are broken in this version of Boost!
-#endif
-
-std::unique_ptr<Source> sinkToSource(const std::function<void(Sink&)>& fun,
-                                     const std::function<void()>& eof) {
-  struct SinkToSource : Source {
-    using coro_t = boost::coroutines2::coroutine<std::string>;
-
-    std::function<void(Sink&)> fun;
-    std::function<void()> eof;
-    std::optional<coro_t::pull_type> coro;
-    bool started = false;
-
-    SinkToSource(std::function<void(Sink&)> fun, std::function<void()> eof)
-        : fun(std::move(fun)), eof(std::move(eof)) {}
-
-    std::string cur;
-    size_t pos = 0;
-
-    size_t read(unsigned char* data, size_t len) override {
-      if (!coro) {
-        coro = coro_t::pull_type([&](coro_t::push_type& yield) {
-          LambdaSink sink([&](const unsigned char* data, size_t len) {
-            if (len != 0u) {
-              yield(std::string(reinterpret_cast<const char*>(data), len));
-            }
-          });
-          fun(sink);
-        });
-      }
-
-      if (!*coro) {
-        eof();
-        abort();
-      }
-
-      if (pos == cur.size()) {
-        if (!cur.empty()) {
-          (*coro)();
-        }
-        cur = coro->get();
-        pos = 0;
-      }
-
-      auto n = std::min(cur.size() - pos, len);
-      memcpy(data, reinterpret_cast<unsigned char*>(cur.data()) + pos, n);
-      pos += n;
-
-      return n;
-    }
-  };
-
-  return std::make_unique<SinkToSource>(fun, eof);
-}
-
-void writePadding(size_t len, Sink& sink) {
-  if ((len % 8) != 0u) {
-    unsigned char zero[8];
-    memset(zero, 0, sizeof(zero));
-    sink(zero, 8 - (len % 8));
-  }
-}
-
-void writeString(const unsigned char* buf, size_t len, Sink& sink) {
-  sink << len;
-  sink(buf, len);
-  writePadding(len, sink);
-}
-
-Sink& operator<<(Sink& sink, const std::string& s) {
-  writeString(reinterpret_cast<const unsigned char*>(s.data()), s.size(), sink);
-  return sink;
-}
-
-template <class T>
-void writeStrings(const T& ss, Sink& sink) {
-  sink << ss.size();
-  for (auto& i : ss) {
-    sink << i;
-  }
-}
-
-Sink& operator<<(Sink& sink, const Strings& s) {
-  writeStrings(s, sink);
-  return sink;
-}
-
-Sink& operator<<(Sink& sink, const StringSet& s) {
-  writeStrings(s, sink);
-  return sink;
-}
-
-void readPadding(size_t len, Source& source) {
-  if ((len % 8) != 0u) {
-    unsigned char zero[8];
-    size_t n = 8 - (len % 8);
-    source(zero, n);
-    for (unsigned int i = 0; i < n; i++) {
-      if (zero[i] != 0u) {
-        throw SerialisationError("non-zero padding");
-      }
-    }
-  }
-}
-
-size_t readString(unsigned char* buf, size_t max, Source& source) {
-  auto len = readNum<size_t>(source);
-  if (len > max) {
-    throw SerialisationError("string is too long");
-  }
-  source(buf, len);
-  readPadding(len, source);
-  return len;
-}
-
-std::string readString(Source& source, size_t max) {
-  auto len = readNum<size_t>(source);
-  if (len > max) {
-    throw SerialisationError("string is too long");
-  }
-  std::string res(len, 0);
-  source(reinterpret_cast<unsigned char*>(res.data()), len);
-  readPadding(len, source);
-  return res;
-}
-
-Source& operator>>(Source& in, std::string& s) {
-  s = readString(in);
-  return in;
-}
-
-template <class T>
-T readStrings(Source& source) {
-  auto count = readNum<size_t>(source);
-  T ss;
-  while (count--) {
-    ss.insert(ss.end(), readString(source));
-  }
-  return ss;
-}
-
-template Paths readStrings(Source& source);
-template PathSet readStrings(Source& source);
-
-void StringSink::operator()(const unsigned char* data, size_t len) {
-  static bool warned = false;
-  if (!warned && s->size() > threshold) {
-    warnLargeDump();
-    warned = true;
-  }
-  s->append(reinterpret_cast<const char*>(data), len);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/serialise.hh b/third_party/nix/src/libutil/serialise.hh
deleted file mode 100644
index c6d1d814dbdd..000000000000
--- a/third_party/nix/src/libutil/serialise.hh
+++ /dev/null
@@ -1,289 +0,0 @@
-#pragma once
-
-#include <memory>
-
-#include "libutil/types.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-/* Abstract destination of binary data. */
-struct Sink {
-  virtual ~Sink() {}
-  virtual void operator()(const unsigned char* data, size_t len) = 0;
-  virtual bool good() { return true; }
-
-  void operator()(const std::string& s) {
-    (*this)((const unsigned char*)s.data(), s.size());
-  }
-};
-
-/* A buffered abstract sink. */
-struct BufferedSink : Sink {
-  size_t bufSize, bufPos;
-  std::unique_ptr<unsigned char[]> buffer;
-
-  explicit BufferedSink(size_t bufSize = 32 * 1024)
-      : bufSize(bufSize), bufPos(0), buffer(nullptr) {}
-
-  void operator()(const unsigned char* data, size_t len) override;
-
-  void operator()(const std::string& s) { Sink::operator()(s); }
-
-  void flush();
-
-  virtual void write(const unsigned char* data, size_t len) = 0;
-};
-
-/* Abstract source of binary data. */
-struct Source {
-  virtual ~Source() {}
-
-  /* Store exactly ‘len’ bytes in the buffer pointed to by ‘data’.
-     It blocks until all the requested data is available, or throws
-     an error if it is not going to be available.   */
-  void operator()(unsigned char* data, size_t len);
-
-  /* Store up to ‘len’ in the buffer pointed to by ‘data’, and
-     return the number of bytes stored.  It blocks until at least
-     one byte is available. */
-  virtual size_t read(unsigned char* data, size_t len) = 0;
-
-  virtual bool good() { return true; }
-
-  std::string drain();
-};
-
-/* A buffered abstract source. */
-struct BufferedSource : Source {
-  size_t bufSize, bufPosIn, bufPosOut;
-  std::unique_ptr<unsigned char[]> buffer;
-
-  explicit BufferedSource(size_t bufSize = 32 * 1024)
-      : bufSize(bufSize), bufPosIn(0), bufPosOut(0), buffer(nullptr) {}
-
-  size_t read(unsigned char* data, size_t len) override;
-
-  bool hasData();
-
- protected:
-  /* Underlying read call, to be overridden. */
-  virtual size_t readUnbuffered(unsigned char* data, size_t len) = 0;
-};
-
-/* A sink that writes data to a file descriptor. */
-struct FdSink : BufferedSink {
-  int fd;
-  bool warn = false;
-  size_t written = 0;
-
-  FdSink() : fd(-1) {}
-  explicit FdSink(int fd) : fd(fd) {}
-  FdSink(FdSink&&) = default;
-
-  FdSink& operator=(FdSink&& s) {
-    flush();
-    fd = s.fd;
-    s.fd = -1;
-    warn = s.warn;
-    written = s.written;
-    return *this;
-  }
-
-  ~FdSink();
-
-  void write(const unsigned char* data, size_t len) override;
-
-  bool good() override;
-
- private:
-  bool _good = true;
-};
-
-/* A source that reads data from a file descriptor. */
-struct FdSource : BufferedSource {
-  int fd;
-  size_t read = 0;
-
-  FdSource() : fd(-1) {}
-  explicit FdSource(int fd) : fd(fd) {}
-  FdSource(FdSource&&) = default;
-
-  FdSource& operator=(FdSource&& s) {
-    fd = s.fd;
-    s.fd = -1;
-    read = s.read;
-    return *this;
-  }
-
-  bool good() override;
-
- protected:
-  size_t readUnbuffered(unsigned char* data, size_t len) override;
-
- private:
-  bool _good = true;
-};
-
-/* A sink that writes data to a string. */
-struct StringSink : Sink {
-  ref<std::string> s;
-  StringSink() : s(make_ref<std::string>()){};
-  explicit StringSink(ref<std::string> s) : s(s){};
-  void operator()(const unsigned char* data, size_t len) override;
-};
-
-/* A source that reads data from a string. */
-struct StringSource : Source {
-  const std::string& s;
-  size_t pos;
-  explicit StringSource(const std::string& _s) : s(_s), pos(0) {}
-  size_t read(unsigned char* data, size_t len) override;
-};
-
-/* Adapter class of a Source that saves all data read to `s'. */
-struct TeeSource : Source {
-  Source& orig;
-  ref<std::string> data;
-  explicit TeeSource(Source& orig)
-      : orig(orig), data(make_ref<std::string>()) {}
-  size_t read(unsigned char* data, size_t len) {
-    size_t n = orig.read(data, len);
-    this->data->append((const char*)data, n);
-    return n;
-  }
-};
-
-/* A reader that consumes the original Source until 'size'. */
-struct SizedSource : Source {
-  Source& orig;
-  size_t remain;
-  SizedSource(Source& orig, size_t size) : orig(orig), remain(size) {}
-  size_t read(unsigned char* data, size_t len) {
-    if (this->remain <= 0) {
-      throw EndOfFile("sized: unexpected end-of-file");
-    }
-    len = std::min(len, this->remain);
-    size_t n = this->orig.read(data, len);
-    this->remain -= n;
-    return n;
-  }
-
-  /* Consume the original source until no remain data is left to consume. */
-  size_t drainAll() {
-    std::vector<unsigned char> buf(8192);
-    size_t sum = 0;
-    while (this->remain > 0) {
-      size_t n = read(buf.data(), buf.size());
-      sum += n;
-    }
-    return sum;
-  }
-};
-
-/* Convert a function into a sink. */
-struct LambdaSink : Sink {
-  typedef std::function<void(const unsigned char*, size_t)> lambda_t;
-
-  lambda_t lambda;
-
-  explicit LambdaSink(const lambda_t& lambda) : lambda(lambda) {}
-
-  virtual void operator()(const unsigned char* data, size_t len) {
-    lambda(data, len);
-  }
-};
-
-/* Convert a function into a source. */
-struct LambdaSource : Source {
-  using lambda_t = std::function<size_t(unsigned char*, size_t)>;
-
-  lambda_t lambda;
-
-  explicit LambdaSource(const lambda_t& lambda) : lambda(lambda) {}
-
-  size_t read(unsigned char* data, size_t len) override {
-    return lambda(data, len);
-  }
-};
-
-/* Convert a function that feeds data into a Sink into a Source. The
-   Source executes the function as a coroutine. */
-std::unique_ptr<Source> sinkToSource(
-    const std::function<void(Sink&)>& fun,
-    const std::function<void()>& eof = []() {
-      throw EndOfFile("coroutine has finished");
-    });
-
-void writePadding(size_t len, Sink& sink);
-void writeString(const unsigned char* buf, size_t len, Sink& sink);
-
-inline Sink& operator<<(Sink& sink, uint64_t n) {
-  unsigned char buf[8];
-  buf[0] = n & 0xff;
-  buf[1] = (n >> 8) & 0xff;
-  buf[2] = (n >> 16) & 0xff;
-  buf[3] = (n >> 24) & 0xff;
-  buf[4] = (n >> 32) & 0xff;
-  buf[5] = (n >> 40) & 0xff;
-  buf[6] = (n >> 48) & 0xff;
-  buf[7] = (unsigned char)(n >> 56) & 0xff;
-  sink(buf, sizeof(buf));
-  return sink;
-}
-
-Sink& operator<<(Sink& sink, const std::string& s);
-Sink& operator<<(Sink& sink, const Strings& s);
-Sink& operator<<(Sink& sink, const StringSet& s);
-
-MakeError(SerialisationError, Error);
-
-template <typename T>
-T readNum(Source& source) {
-  unsigned char buf[8];
-  source(buf, sizeof(buf));
-
-  uint64_t n =
-      ((unsigned long long)buf[0]) | ((unsigned long long)buf[1] << 8) |
-      ((unsigned long long)buf[2] << 16) | ((unsigned long long)buf[3] << 24) |
-      ((unsigned long long)buf[4] << 32) | ((unsigned long long)buf[5] << 40) |
-      ((unsigned long long)buf[6] << 48) | ((unsigned long long)buf[7] << 56);
-
-  if (n > std::numeric_limits<T>::max()) {
-    throw SerialisationError("serialised integer %d is too large for type '%s'",
-                             n, typeid(T).name());
-  }
-
-  return (T)n;
-}
-
-inline unsigned int readInt(Source& source) {
-  return readNum<unsigned int>(source);
-}
-
-inline uint64_t readLongLong(Source& source) {
-  return readNum<uint64_t>(source);
-}
-
-void readPadding(size_t len, Source& source);
-size_t readString(unsigned char* buf, size_t max, Source& source);
-std::string readString(Source& source,
-                       size_t max = std::numeric_limits<size_t>::max());
-template <class T>
-T readStrings(Source& source);
-
-Source& operator>>(Source& in, std::string& s);
-
-template <typename T>
-Source& operator>>(Source& in, T& n) {
-  n = readNum<T>(in);
-  return in;
-}
-
-template <typename T>
-Source& operator>>(Source& in, bool& b) {
-  b = readNum<uint64_t>(in);
-  return in;
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/status.hh b/third_party/nix/src/libutil/status.hh
deleted file mode 100644
index aeee0f502257..000000000000
--- a/third_party/nix/src/libutil/status.hh
+++ /dev/null
@@ -1,17 +0,0 @@
-#pragma once
-
-#include <absl/status/status.h>
-#include <absl/strings/str_format.h>
-#include <absl/strings/string_view.h>
-
-#include "libutil/types.hh"
-
-namespace nix::util {
-
-inline void OkOrThrow(absl::Status status) {
-  if (!status.ok()) {
-    throw Error(absl::StrFormat("Operation failed: %s", status.ToString()));
-  }
-}
-
-}  // namespace nix::util
diff --git a/third_party/nix/src/libutil/sync.hh b/third_party/nix/src/libutil/sync.hh
deleted file mode 100644
index ef640d5b56ef..000000000000
--- a/third_party/nix/src/libutil/sync.hh
+++ /dev/null
@@ -1,84 +0,0 @@
-#pragma once
-
-#include <cassert>
-#include <condition_variable>
-#include <cstdlib>
-#include <mutex>
-
-namespace nix {
-
-/* This template class ensures synchronized access to a value of type
-   T. It is used as follows:
-
-     struct Data { int x; ... };
-
-     Sync<Data> data;
-
-     {
-       auto data_(data.lock());
-       data_->x = 123;
-     }
-
-   Here, "data" is automatically unlocked when "data_" goes out of
-   scope.
-*/
-
-template <class T, class M = std::mutex>
-class Sync {
- private:
-  M mutex;
-  T data;
-
- public:
-  Sync() {}
-  explicit Sync(const T& data) : data(data) {}
-  explicit Sync(T&& data) noexcept : data(std::move(data)) {}
-
-  class Lock {
-   private:
-    Sync* s;
-    std::unique_lock<M> lk;
-    friend Sync;
-    explicit Lock(Sync* s) : s(s), lk(s->mutex) {}
-
-   public:
-    Lock(Lock&& l) : s(l.s) { abort(); }
-    Lock(const Lock& l) = delete;
-    ~Lock() {}
-    T* operator->() { return &s->data; }
-    T& operator*() { return s->data; }
-
-    void wait(std::condition_variable& cv) {
-      assert(s);
-      cv.wait(lk);
-    }
-
-    template <class Rep, class Period>
-    std::cv_status wait_for(
-        std::condition_variable& cv,
-        const std::chrono::duration<Rep, Period>& duration) {
-      assert(s);
-      return cv.wait_for(lk, duration);
-    }
-
-    template <class Rep, class Period, class Predicate>
-    bool wait_for(std::condition_variable& cv,
-                  const std::chrono::duration<Rep, Period>& duration,
-                  Predicate pred) {
-      assert(s);
-      return cv.wait_for(lk, duration, pred);
-    }
-
-    template <class Clock, class Duration>
-    std::cv_status wait_until(
-        std::condition_variable& cv,
-        const std::chrono::time_point<Clock, Duration>& duration) {
-      assert(s);
-      return cv.wait_until(lk, duration);
-    }
-  };
-
-  Lock lock() { return Lock(this); }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/thread-pool.cc b/third_party/nix/src/libutil/thread-pool.cc
deleted file mode 100644
index 7c6b0a1b469b..000000000000
--- a/third_party/nix/src/libutil/thread-pool.cc
+++ /dev/null
@@ -1,163 +0,0 @@
-#include "libutil/thread-pool.hh"
-
-#include <glog/logging.h>
-
-#include "libutil/affinity.hh"
-
-namespace nix {
-
-ThreadPool::ThreadPool(size_t _maxThreads) : maxThreads(_maxThreads) {
-  restoreAffinity();  // FIXME
-
-  if (maxThreads == 0u) {
-    maxThreads = std::thread::hardware_concurrency();
-    if (maxThreads == 0u) {
-      maxThreads = 1;
-    }
-  }
-
-  DLOG(INFO) << "starting pool of " << maxThreads - 1 << " threads";
-}
-
-ThreadPool::~ThreadPool() { shutdown(); }
-
-void ThreadPool::shutdown() {
-  std::vector<std::thread> workers;
-  {
-    auto state(state_.lock());
-    quit = true;
-    std::swap(workers, state->workers);
-  }
-
-  if (workers.empty()) {
-    return;
-  }
-
-  DLOG(INFO) << "reaping " << workers.size() << " worker threads";
-
-  work.notify_all();
-
-  for (auto& thr : workers) {
-    thr.join();
-  }
-}
-
-void ThreadPool::enqueue(const work_t& t) {
-  auto state(state_.lock());
-  if (quit) {
-    throw ThreadPoolShutDown(
-        "cannot enqueue a work item while the thread pool is shutting down");
-  }
-  state->pending.push(t);
-  /* Note: process() also executes items, so count it as a worker. */
-  if (state->pending.size() > state->workers.size() + 1 &&
-      state->workers.size() + 1 < maxThreads) {
-    state->workers.emplace_back(&ThreadPool::doWork, this, false);
-  }
-  work.notify_one();
-}
-
-void ThreadPool::process() {
-  state_.lock()->draining = true;
-
-  /* Do work until no more work is pending or active. */
-  try {
-    doWork(true);
-
-    auto state(state_.lock());
-
-    assert(quit);
-
-    if (state->exception) {
-      std::rethrow_exception(state->exception);
-    }
-
-  } catch (...) {
-    /* In the exceptional case, some workers may still be
-       active. They may be referencing the stack frame of the
-       caller. So wait for them to finish. (~ThreadPool also does
-       this, but it might be destroyed after objects referenced by
-       the work item lambdas.) */
-    shutdown();
-    throw;
-  }
-}
-
-void ThreadPool::doWork(bool mainThread) {
-  if (!mainThread) {
-    interruptCheck = [&]() { return (bool)quit; };
-  }
-
-  bool didWork = false;
-  std::exception_ptr exc;
-
-  while (true) {
-    work_t w;
-    {
-      auto state(state_.lock());
-
-      if (didWork) {
-        assert(state->active);
-        state->active--;
-
-        if (exc) {
-          if (!state->exception) {
-            state->exception = exc;
-            // Tell the other workers to quit.
-            quit = true;
-            work.notify_all();
-          } else {
-            /* Print the exception, since we can't
-               propagate it. */
-            try {
-              std::rethrow_exception(exc);
-            } catch (std::exception& e) {
-              if ((dynamic_cast<Interrupted*>(&e) == nullptr) &&
-                  (dynamic_cast<ThreadPoolShutDown*>(&e) == nullptr)) {
-                ignoreException();
-              }
-            } catch (...) {
-            }
-          }
-        }
-      }
-
-      /* Wait until a work item is available or we're asked to
-         quit. */
-      while (true) {
-        if (quit) {
-          return;
-        }
-
-        if (!state->pending.empty()) {
-          break;
-        }
-
-        /* If there are no active or pending items, and the
-           main thread is running process(), then no new items
-           can be added. So exit. */
-        if ((state->active == 0u) && state->draining) {
-          quit = true;
-          work.notify_all();
-          return;
-        }
-
-        state.wait(work);
-      }
-
-      w = std::move(state->pending.front());
-      state->pending.pop();
-      state->active++;
-    }
-
-    try {
-      w();
-    } catch (...) {
-      exc = std::current_exception();
-    }
-
-    didWork = true;
-  }
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/thread-pool.hh b/third_party/nix/src/libutil/thread-pool.hh
deleted file mode 100644
index 0efc4c1bfc67..000000000000
--- a/third_party/nix/src/libutil/thread-pool.hh
+++ /dev/null
@@ -1,140 +0,0 @@
-#pragma once
-
-#include <atomic>
-#include <functional>
-#include <map>
-#include <queue>
-#include <thread>
-
-#include "libutil/sync.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-MakeError(ThreadPoolShutDown, Error);
-
-/* A simple thread pool that executes a queue of work items
-   (lambdas). */
-class ThreadPool {
- public:
-  explicit ThreadPool(size_t maxThreads = 0);
-
-  ~ThreadPool();
-
-  // FIXME: use std::packaged_task?
-  typedef std::function<void()> work_t;
-
-  /* Enqueue a function to be executed by the thread pool. */
-  void enqueue(const work_t& t);
-
-  /* Execute work items until the queue is empty. Note that work
-     items are allowed to add new items to the queue; this is
-     handled correctly. Queue processing stops prematurely if any
-     work item throws an exception. This exception is propagated to
-     the calling thread. If multiple work items throw an exception
-     concurrently, only one item is propagated; the others are
-     printed on stderr and otherwise ignored. */
-  void process();
-
- private:
-  size_t maxThreads;
-
-  struct State {
-    std::queue<work_t> pending;
-    size_t active = 0;
-    std::exception_ptr exception;
-    std::vector<std::thread> workers;
-    bool draining = false;
-  };
-
-  std::atomic_bool quit{false};
-
-  Sync<State> state_;
-
-  std::condition_variable work;
-
-  void doWork(bool mainThread);
-
-  void shutdown();
-};
-
-/* Process in parallel a set of items of type T that have a partial
-   ordering between them. Thus, any item is only processed after all
-   its dependencies have been processed. */
-template <typename T>
-void processGraph(ThreadPool& pool, const std::set<T>& nodes,
-                  std::function<std::set<T>(const T&)> getEdges,
-                  std::function<void(const T&)> processNode) {
-  struct Graph {
-    std::set<T> left;
-    std::map<T, std::set<T>> refs, rrefs;
-  };
-
-  Sync<Graph> graph_(Graph{nodes, {}, {}});
-
-  std::function<void(const T&)> worker;
-
-  worker = [&](const T& node) {
-    {
-      auto graph(graph_.lock());
-      auto i = graph->refs.find(node);
-      if (i == graph->refs.end()) {
-        goto getRefs;
-      }
-      goto doWork;
-    }
-
-  getRefs : {
-    auto refs = getEdges(node);
-    refs.erase(node);
-
-    {
-      auto graph(graph_.lock());
-      for (auto& ref : refs) {
-        if (graph->left.count(ref)) {
-          graph->refs[node].insert(ref);
-          graph->rrefs[ref].insert(node);
-        }
-      }
-      if (graph->refs[node].empty()) {
-        goto doWork;
-      }
-    }
-  }
-
-    return;
-
-  doWork:
-    processNode(node);
-
-    /* Enqueue work for all nodes that were waiting on this one
-       and have no unprocessed dependencies. */
-    {
-      auto graph(graph_.lock());
-      for (auto& rref : graph->rrefs[node]) {
-        auto& refs(graph->refs[rref]);
-        auto i = refs.find(node);
-        assert(i != refs.end());
-        refs.erase(i);
-        if (refs.empty()) {
-          pool.enqueue(std::bind(worker, rref));
-        }
-      }
-      graph->left.erase(node);
-      graph->refs.erase(node);
-      graph->rrefs.erase(node);
-    }
-  };
-
-  for (auto& node : nodes) {
-    pool.enqueue(std::bind(worker, std::ref(node)));
-  }
-
-  pool.process();
-
-  if (!graph_.lock()->left.empty()) {
-    throw Error("graph processing incomplete (cyclic reference?)");
-  }
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/types.hh b/third_party/nix/src/libutil/types.hh
deleted file mode 100644
index bf95206d0824..000000000000
--- a/third_party/nix/src/libutil/types.hh
+++ /dev/null
@@ -1,118 +0,0 @@
-#pragma once
-
-#include <boost/format.hpp>
-#include <list>
-#include <map>
-#include <memory>
-#include <set>
-#include <string>
-
-#include "libutil/ref.hh"
-
-/* Before 4.7, gcc's std::exception uses empty throw() specifiers for
- * its (virtual) destructor and what() in c++11 mode, in violation of spec
- */
-#ifdef __GNUC__
-#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
-#define EXCEPTION_NEEDS_THROW_SPEC
-#endif
-#endif
-
-namespace nix {
-
-/* Inherit some names from other namespaces for convenience. */
-using boost::format;
-
-/* A variadic template that does nothing. Useful to call a function
-   for all variadic arguments but ignoring the result. */
-struct nop {
-  template <typename... T>
-  explicit nop(T...) {}
-};
-
-struct FormatOrString {
-  std::string s;
-  FormatOrString(const std::string& s) : s(s){};
-  FormatOrString(const format& f) : s(f.str()){};
-  FormatOrString(const char* s) : s(s){};
-};
-
-/* A helper for formatting strings. ‘fmt(format, a_0, ..., a_n)’ is
-   equivalent to ‘boost::format(format) % a_0 % ... %
-   ... a_n’. However, ‘fmt(s)’ is equivalent to ‘s’ (so no %-expansion
-   takes place). */
-
-inline std::string fmt(const std::string& s) { return s; }
-
-inline std::string fmt(std::string_view s) { return std::string(s); }
-
-inline std::string fmt(const char* s) { return s; }
-
-inline std::string fmt(const FormatOrString& fs) { return fs.s; }
-
-template <typename... Args>
-inline std::string fmt(const std::string& fs, Args... args) {
-  boost::format f(fs);
-  f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
-  nop{boost::io::detail::feed(f, args)...};
-  return f.str();
-}
-
-/* BaseError should generally not be caught, as it has Interrupted as
-   a subclass. Catch Error instead. */
-class BaseError : public std::exception {
- protected:
-  std::string prefix_;  // used for location traces etc.
-  std::string err;
-
- public:
-  unsigned int status = 1;  // exit status
-
-  template <typename... Args>
-  explicit BaseError(unsigned int status, Args... args)
-      : err(fmt(args...)), status(status) {}
-
-  template <typename... Args>
-  explicit BaseError(Args... args) : err(fmt(args...)) {}
-
-#ifdef EXCEPTION_NEEDS_THROW_SPEC
-  ~BaseError() noexcept {};
-  const char* what() const noexcept { return err.c_str(); }
-#else
-  const char* what() const noexcept { return err.c_str(); }
-#endif
-
-  const std::string& msg() const { return err; }
-  const std::string& prefix() const { return prefix_; }
-  BaseError& addPrefix(const FormatOrString& fs);
-};
-
-#define MakeError(newClass, superClass) \
-  class newClass : public superClass {  \
-   public:                              \
-    using superClass::superClass;       \
-  };
-
-MakeError(Error, BaseError);
-
-class SysError : public Error {
- public:
-  int errNo;
-
-  template <typename... Args>
-  explicit SysError(Args... args) : Error(addErrno(fmt(args...))) {}
-
- private:
-  std::string addErrno(const std::string& s);
-};
-
-typedef std::list<std::string> Strings;
-using StringSet = std::set<std::string>;
-using StringMap = std::map<std::string, std::string>;
-
-/* Paths are just strings. */
-using Path = std::string;
-using Paths = std::list<Path>;
-using PathSet = std::set<Path>;
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/util.cc b/third_party/nix/src/libutil/util.cc
deleted file mode 100644
index aea1e68e3c77..000000000000
--- a/third_party/nix/src/libutil/util.cc
+++ /dev/null
@@ -1,1426 +0,0 @@
-#include "libutil/util.hh"
-
-#include <cctype>
-#include <cerrno>
-#include <climits>
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
-#include <future>
-#include <iostream>
-#include <sstream>
-#include <thread>
-#include <utility>
-
-#include <absl/strings/str_split.h>
-#include <absl/strings/string_view.h>
-#include <fcntl.h>
-#include <glog/logging.h>
-#include <grp.h>
-#include <pwd.h>
-#include <sys/ioctl.h>
-#include <sys/prctl.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-#include "libutil/affinity.hh"
-#include "libutil/finally.hh"
-#include "libutil/lazy.hh"
-#include "libutil/serialise.hh"
-#include "libutil/sync.hh"
-#include "nix_config.h"
-
-namespace nix {
-
-const std::string nativeSystem = SYSTEM;
-
-BaseError& BaseError::addPrefix(const FormatOrString& fs) {
-  prefix_ = fs.s + prefix_;
-  return *this;
-}
-
-std::string SysError::addErrno(const std::string& s) {
-  errNo = errno;
-  return s + ": " + strerror(errNo);
-}
-
-std::optional<std::string> getEnv(const std::string& key) {
-  char* value = getenv(key.c_str());
-  if (value == nullptr) return {};
-  return std::string(value);
-}
-
-std::map<std::string, std::string> getEnv() {
-  std::map<std::string, std::string> env;
-  for (size_t i = 0; environ[i] != nullptr; ++i) {
-    auto s = environ[i];
-    auto eq = strchr(s, '=');
-    if (eq == nullptr) {
-      // invalid env, just keep going
-      continue;
-    }
-    env.emplace(std::string(s, eq), std::string(eq + 1));
-  }
-  return env;
-}
-
-void clearEnv() {
-  for (auto& name : getEnv()) {
-    unsetenv(name.first.c_str());
-  }
-}
-
-void replaceEnv(const std::map<std::string, std::string>& newEnv) {
-  clearEnv();
-  for (const auto& newEnvVar : newEnv) {
-    setenv(newEnvVar.first.c_str(), newEnvVar.second.c_str(), 1);
-  }
-}
-
-Path absPath(Path path, Path dir) {
-  if (path[0] != '/') {
-    if (dir.empty()) {
-#ifdef __GNU__
-      /* GNU (aka. GNU/Hurd) doesn't have any limitation on path
-         lengths and doesn't define `PATH_MAX'.  */
-      char* buf = getcwd(NULL, 0);
-      if (buf == NULL)
-#else
-      char buf[PATH_MAX];
-      if (getcwd(buf, sizeof(buf)) == nullptr) {
-#endif
-        throw SysError("cannot get cwd");
-    }
-    dir = buf;
-#ifdef __GNU__
-    free(buf);
-#endif
-  }
-  path = dir + "/" + path;
-}
-return canonPath(path);
-}  // namespace nix
-
-Path canonPath(const Path& path, bool resolveSymlinks) {
-  assert(!path.empty());
-
-  std::string s;
-
-  if (path[0] != '/') {
-    throw Error(format("not an absolute path: '%1%'") % path);
-  }
-
-  std::string::const_iterator i = path.begin();
-  std::string::const_iterator end = path.end();
-  std::string temp;
-
-  /* Count the number of times we follow a symlink and stop at some
-     arbitrary (but high) limit to prevent infinite loops. */
-  unsigned int followCount = 0;
-  unsigned int maxFollow = 1024;
-
-  while (true) {
-    /* Skip slashes. */
-    while (i != end && *i == '/') {
-      i++;
-    }
-    if (i == end) {
-      break;
-    }
-
-    /* Ignore `.'. */
-    if (*i == '.' && (i + 1 == end || i[1] == '/')) {
-      i++;
-    }
-
-    /* If `..', delete the last component. */
-    else if (*i == '.' && i + 1 < end && i[1] == '.' &&
-             (i + 2 == end || i[2] == '/')) {
-      if (!s.empty()) {
-        s.erase(s.rfind('/'));
-      }
-      i += 2;
-    }
-
-    /* Normal component; copy it. */
-    else {
-      s += '/';
-      while (i != end && *i != '/') {
-        s += *i++;
-      }
-
-      /* If s points to a symlink, resolve it and restart (since
-         the symlink target might contain new symlinks). */
-      if (resolveSymlinks && isLink(s)) {
-        if (++followCount >= maxFollow) {
-          throw Error(format("infinite symlink recursion in path '%1%'") %
-                      path);
-        }
-        temp = absPath(readLink(s), dirOf(s)) + std::string(i, end);
-        i = temp.begin(); /* restart */
-        end = temp.end();
-        s = "";
-      }
-    }
-  }
-
-  return s.empty() ? "/" : s;
-}
-
-// TODO(grfn) remove in favor of std::filesystem::path::parent_path()
-Path dirOf(absl::string_view path) {
-  Path::size_type pos = path.rfind('/');
-  if (pos == std::string::npos) {
-    return ".";
-  }
-  return pos == 0 ? "/" : Path(path, 0, pos);
-}
-
-// TODO(grfn) remove in favor of std::filesystem::path::root_name()
-std::string baseNameOf(const Path& path) {
-  if (path.empty()) {
-    return "";
-  }
-
-  Path::size_type last = path.length() - 1;
-  if (path[last] == '/' && last > 0) {
-    last -= 1;
-  }
-
-  Path::size_type pos = path.rfind('/', last);
-  if (pos == std::string::npos) {
-    pos = 0;
-  } else {
-    pos += 1;
-  }
-
-  return std::string(path, pos, last - pos + 1);
-}
-
-bool isInDir(const Path& path, const Path& dir) {
-  return path[0] == '/' && std::string(path, 0, dir.size()) == dir &&
-         path.size() >= dir.size() + 2 && path[dir.size()] == '/';
-}
-
-bool isDirOrInDir(const Path& path, const Path& dir) {
-  return path == dir || isInDir(path, dir);
-}
-
-struct stat lstat(const Path& path) {
-  struct stat st;
-  if (lstat(path.c_str(), &st) != 0) {
-    throw SysError(format("getting status of '%1%'") % path);
-  }
-  return st;
-}
-
-bool pathExists(const Path& path) {
-  int res;
-  struct stat st;
-  res = lstat(path.c_str(), &st);
-  if (res == 0) {
-    return true;
-  }
-  if (errno != ENOENT && errno != ENOTDIR) {
-    throw SysError(format("getting status of %1%") % path);
-  }
-  return false;
-}
-
-Path readLink(const Path& path) {
-  checkInterrupt();
-  std::vector<char> buf;
-  for (ssize_t bufSize = PATH_MAX / 4; true; bufSize += bufSize / 2) {
-    buf.resize(bufSize);
-    ssize_t rlSize = readlink(path.c_str(), buf.data(), bufSize);
-    if (rlSize == -1) {
-      if (errno == EINVAL) {
-        throw Error("'%1%' is not a symlink", path);
-      }
-      throw SysError("reading symbolic link '%1%'", path);
-
-    } else if (rlSize < bufSize) {
-      return std::string(buf.data(), rlSize);
-    }
-  }
-}
-
-bool isLink(const Path& path) {
-  struct stat st = lstat(path);
-  return S_ISLNK(st.st_mode);
-}
-
-DirEntries readDirectory(DIR* dir, const Path& path) {
-  DirEntries entries;
-  entries.reserve(64);
-
-  struct dirent* dirent;
-  while (errno = 0, dirent = readdir(dir)) { /* sic */
-    checkInterrupt();
-    std::string name = dirent->d_name;
-    if (name == "." || name == "..") {
-      continue;
-    }
-    entries.emplace_back(name, dirent->d_ino,
-#ifdef HAVE_STRUCT_DIRENT_D_TYPE
-                         dirent->d_type
-#else
-                         DT_UNKNOWN
-#endif
-    );
-  }
-  if (errno) {
-    throw SysError(format("reading directory '%1%'") % path);
-  }
-
-  return entries;
-}
-
-DirEntries readDirectory(const Path& path) {
-  AutoCloseDir dir(opendir(path.c_str()));
-  if (!dir) {
-    throw SysError(format("opening directory '%1%'") % path);
-  }
-
-  return readDirectory(dir.get(), path);
-}
-
-unsigned char getFileType(const Path& path) {
-  struct stat st = lstat(path);
-  if (S_ISDIR(st.st_mode)) {
-    return DT_DIR;
-  }
-  if (S_ISLNK(st.st_mode)) {
-    return DT_LNK;
-  }
-  if (S_ISREG(st.st_mode)) {
-    return DT_REG;
-  }
-  return DT_UNKNOWN;
-}
-
-std::string readFile(int fd) {
-  struct stat st;
-  if (fstat(fd, &st) == -1) {
-    throw SysError("statting file");
-  }
-
-  std::vector<unsigned char> buf(st.st_size);
-  readFull(fd, buf.data(), st.st_size);
-
-  return std::string(reinterpret_cast<char*>(buf.data()), st.st_size);
-}
-
-std::string readFile(absl::string_view path, bool drain) {
-  AutoCloseFD fd(open(std::string(path).c_str(), O_RDONLY | O_CLOEXEC));
-  if (!fd) {
-    throw SysError(format("opening file '%1%'") % path);
-  }
-  return drain ? drainFD(fd.get()) : readFile(fd.get());
-}
-
-void readFile(absl::string_view path, Sink& sink) {
-  // TODO(tazjin): use stdlib functions for this stuff
-  AutoCloseFD fd(open(std::string(path).c_str(), O_RDONLY | O_CLOEXEC));
-  if (!fd) {
-    throw SysError("opening file '%s'", path);
-  }
-  drainFD(fd.get(), sink);
-}
-
-void writeFile(const Path& path, const std::string& s, mode_t mode) {
-  AutoCloseFD fd(
-      open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode));
-  if (!fd) {
-    throw SysError(format("opening file '%1%'") % path);
-  }
-  writeFull(fd.get(), s);
-}
-
-void writeFile(const Path& path, Source& source, mode_t mode) {
-  AutoCloseFD fd(
-      open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode));
-  if (!fd) {
-    throw SysError(format("opening file '%1%'") % path);
-  }
-
-  std::vector<unsigned char> buf(64 * 1024);
-
-  while (true) {
-    try {
-      auto n = source.read(buf.data(), buf.size());
-      writeFull(fd.get(), static_cast<unsigned char*>(buf.data()), n);
-    } catch (EndOfFile&) {
-      break;
-    }
-  }
-}
-
-std::string readLine(int fd) {
-  std::string s;
-  while (true) {
-    checkInterrupt();
-    char ch;
-    // FIXME: inefficient
-    ssize_t rd = read(fd, &ch, 1);
-    if (rd == -1) {
-      if (errno != EINTR) {
-        throw SysError("reading a line");
-      }
-    } else if (rd == 0) {
-      throw EndOfFile("unexpected EOF reading a line");
-    } else {
-      if (ch == '\n') {
-        return s;
-      }
-      s += ch;
-    }
-  }
-}
-
-void writeLine(int fd, std::string s) {
-  s += '\n';
-  writeFull(fd, s);
-}
-
-static void _deletePath(int parentfd, const Path& path,
-                        unsigned long long& bytesFreed) {
-  checkInterrupt();
-
-  std::string name(baseNameOf(path));
-
-  struct stat st;
-  if (fstatat(parentfd, name.c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
-    if (errno == ENOENT) {
-      return;
-    }
-    throw SysError(format("getting status of '%1%'") % path);
-  }
-
-  if (!S_ISDIR(st.st_mode) && st.st_nlink == 1) {
-    bytesFreed += st.st_size;
-  }
-
-  if (S_ISDIR(st.st_mode)) {
-    /* Make the directory accessible. */
-    const auto PERM_MASK = S_IRUSR | S_IWUSR | S_IXUSR;
-    if ((st.st_mode & PERM_MASK) != PERM_MASK) {
-      if (fchmodat(parentfd, name.c_str(), st.st_mode | PERM_MASK, 0) == -1) {
-        throw SysError(format("chmod '%1%'") % path);
-      }
-    }
-
-    int fd = openat(parentfd, path.c_str(), O_RDONLY);
-    if (!fd) {
-      throw SysError(format("opening directory '%1%'") % path);
-    }
-    AutoCloseDir dir(fdopendir(fd));
-    if (!dir) {
-      throw SysError(format("opening directory '%1%'") % path);
-    }
-    for (auto& i : readDirectory(dir.get(), path)) {
-      _deletePath(dirfd(dir.get()), path + "/" + i.name, bytesFreed);
-    }
-  }
-
-  int flags = S_ISDIR(st.st_mode) ? AT_REMOVEDIR : 0;
-  if (unlinkat(parentfd, name.c_str(), flags) == -1) {
-    if (errno == ENOENT) {
-      return;
-    }
-    throw SysError(format("cannot unlink '%1%'") % path);
-  }
-}
-
-static void _deletePath(const Path& path, unsigned long long& bytesFreed) {
-  Path dir = dirOf(path);
-  if (dir == "") {
-    dir = "/";
-  }
-
-  AutoCloseFD dirfd(open(dir.c_str(), O_RDONLY));
-  if (!dirfd) {
-    // This really shouldn't fail silently, but it's left this way
-    // for backwards compatibility.
-    if (errno == ENOENT) {
-      return;
-    }
-
-    throw SysError(format("opening directory '%1%'") % path);
-  }
-
-  _deletePath(dirfd.get(), path, bytesFreed);
-}
-
-void deletePath(const Path& path) {
-  unsigned long long dummy;
-  deletePath(path, dummy);
-}
-
-void deletePath(const Path& path, unsigned long long& bytesFreed) {
-  // Activity act(*logger, lvlDebug, format("recursively deleting path '%1%'") %
-  // path);
-  bytesFreed = 0;
-  _deletePath(path, bytesFreed);
-}
-
-static Path tempName(Path tmpRoot, const Path& prefix, bool includePid,
-                     int& counter) {
-  tmpRoot = canonPath(
-      tmpRoot.empty() ? getEnv("TMPDIR").value_or("/tmp") : tmpRoot, true);
-
-  if (includePid) {
-    return (format("%1%/%2%-%3%-%4%") % tmpRoot % prefix % getpid() % counter++)
-        .str();
-  }
-  return (format("%1%/%2%-%3%") % tmpRoot % prefix % counter++).str();
-}
-
-Path createTempDir(const Path& tmpRoot, const Path& prefix, bool includePid,
-                   bool useGlobalCounter, mode_t mode) {
-  static int globalCounter = 0;
-  int localCounter = 0;
-  int& counter(useGlobalCounter ? globalCounter : localCounter);
-
-  while (true) {
-    checkInterrupt();
-    Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
-    if (mkdir(tmpDir.c_str(), mode) == 0) {
-#if __FreeBSD__
-      /* Explicitly set the group of the directory.  This is to
-         work around around problems caused by BSD's group
-         ownership semantics (directories inherit the group of
-         the parent).  For instance, the group of /tmp on
-         FreeBSD is "wheel", so all directories created in /tmp
-         will be owned by "wheel"; but if the user is not in
-         "wheel", then "tar" will fail to unpack archives that
-         have the setgid bit set on directories. */
-      if (chown(tmpDir.c_str(), (uid_t)-1, getegid()) != 0)
-        throw SysError(format("setting group of directory '%1%'") % tmpDir);
-#endif
-      return tmpDir;
-    }
-    if (errno != EEXIST) {
-      throw SysError(format("creating directory '%1%'") % tmpDir);
-    }
-  }
-}
-
-std::string getUserName() {
-  auto pw = getpwuid(geteuid());
-  std::optional<std::string> name =
-      pw != nullptr ? pw->pw_name : getEnv("USER");
-  if (!name.has_value()) {
-    throw Error("cannot figure out user name");
-  }
-  return *name;
-}
-
-static Lazy<Path> getHome2([]() {
-  std::optional<Path> homeDir = getEnv("HOME");
-  if (!homeDir) {
-    std::vector<char> buf(16384);
-    struct passwd pwbuf;
-    struct passwd* pw;
-    if (getpwuid_r(geteuid(), &pwbuf, buf.data(), buf.size(), &pw) != 0 ||
-        (pw == nullptr) || (pw->pw_dir == nullptr) || (pw->pw_dir[0] == 0)) {
-      throw Error("cannot determine user's home directory");
-    }
-    return std::string(pw->pw_dir);
-  }
-  return homeDir.value();
-});
-
-Path getHome() { return getHome2(); }
-
-Path getCacheDir() {
-  return getEnv("XDG_CACHE_HOME").value_or(getHome() + "/.cache");
-}
-
-Path getConfigDir() {
-  return getEnv("XDG_CONFIG_HOME").value_or(getHome() + "/.config");
-}
-
-std::vector<Path> getConfigDirs() {
-  Path configHome = getConfigDir();
-  std::string configDirs = getEnv("XDG_CONFIG_DIRS").value_or("");
-  std::vector<std::string> result =
-      absl::StrSplit(configDirs, absl::ByChar(':'), absl::SkipEmpty());
-  result.insert(result.begin(), configHome);
-  return result;
-}
-
-Path getDataDir() {
-  return getEnv("XDG_DATA_HOME").value_or(getHome() + "/.local/share");
-}
-
-// TODO(grfn): Remove in favor of std::filesystem::create_directories
-Paths createDirs(const Path& path) {
-  Paths created;
-  if (path == "/") {
-    return created;
-  }
-
-  struct stat st;
-  if (lstat(path.c_str(), &st) == -1) {
-    created = createDirs(dirOf(path));
-    if (mkdir(path.c_str(), 0777) == -1 && errno != EEXIST) {
-      throw SysError(format("creating directory '%1%'") % path);
-    }
-    st = lstat(path);
-    created.push_back(path);
-  }
-
-  if (S_ISLNK(st.st_mode) && stat(path.c_str(), &st) == -1) {
-    throw SysError(format("statting symlink '%1%'") % path);
-  }
-
-  if (!S_ISDIR(st.st_mode)) {
-    throw Error(format("'%1%' is not a directory") % path);
-  }
-
-  return created;
-}
-
-void createSymlink(const Path& target, const Path& link) {
-  if (symlink(target.c_str(), link.c_str()) != 0) {
-    throw SysError(format("creating symlink from '%1%' to '%2%'") % link %
-                   target);
-  }
-}
-
-void replaceSymlink(const Path& target, const Path& link) {
-  for (unsigned int n = 0; true; n++) {
-    Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
-
-    try {
-      createSymlink(target, tmp);
-    } catch (SysError& e) {
-      if (e.errNo == EEXIST) {
-        continue;
-      }
-      throw;
-    }
-
-    if (rename(tmp.c_str(), link.c_str()) != 0) {
-      throw SysError(format("renaming '%1%' to '%2%'") % tmp % link);
-    }
-
-    break;
-  }
-}
-
-void readFull(int fd, unsigned char* buf, size_t count) {
-  while (count != 0u) {
-    checkInterrupt();
-    ssize_t res = read(fd, reinterpret_cast<char*>(buf), count);
-    if (res == -1) {
-      if (errno == EINTR) {
-        continue;
-      }
-      throw SysError("reading from file");
-    }
-    if (res == 0) {
-      throw EndOfFile("unexpected end-of-file");
-    }
-    count -= res;
-    buf += res;
-  }
-}
-
-void writeFull(int fd, const unsigned char* buf, size_t count,
-               bool allowInterrupts) {
-  while (count != 0u) {
-    if (allowInterrupts) {
-      checkInterrupt();
-    }
-    ssize_t res = write(fd, (char*)buf, count);
-    if (res == -1 && errno != EINTR) {
-      throw SysError("writing to file");
-    }
-    if (res > 0) {
-      count -= res;
-      buf += res;
-    }
-  }
-}
-
-void writeFull(int fd, const std::string& s, bool allowInterrupts) {
-  writeFull(fd, reinterpret_cast<const unsigned char*>(s.data()), s.size(),
-            allowInterrupts);
-}
-
-std::string drainFD(int fd, bool block) {
-  StringSink sink;
-  drainFD(fd, sink, block);
-  return std::move(*sink.s);
-}
-
-void drainFD(int fd, Sink& sink, bool block) {
-  int saved;
-
-  Finally finally([&]() {
-    if (!block) {
-      if (fcntl(fd, F_SETFL, saved) == -1) {
-        throw SysError("making file descriptor blocking");
-      }
-    }
-  });
-
-  if (!block) {
-    saved = fcntl(fd, F_GETFL);
-    if (fcntl(fd, F_SETFL, saved | O_NONBLOCK) == -1) {
-      throw SysError("making file descriptor non-blocking");
-    }
-  }
-
-  std::vector<unsigned char> buf(64 * 1024);
-  while (true) {
-    checkInterrupt();
-    ssize_t rd = read(fd, buf.data(), buf.size());
-    if (rd == -1) {
-      if (!block && (errno == EAGAIN || errno == EWOULDBLOCK)) {
-        break;
-      }
-      if (errno != EINTR) {
-        throw SysError("reading from file");
-      }
-    } else if (rd == 0) {
-      break;
-    } else {
-      sink(buf.data(), rd);
-    }
-  }
-}
-
-//////////////////////////////////////////////////////////////////////
-
-AutoDelete::AutoDelete() : del{false} {}
-
-AutoDelete::AutoDelete(std::string p, bool recursive) : path(std::move(p)) {
-  del = true;
-  this->recursive = recursive;
-}
-
-AutoDelete::~AutoDelete() {
-  try {
-    if (del) {
-      if (recursive) {
-        deletePath(path);
-      } else {
-        if (remove(path.c_str()) == -1) {
-          throw SysError(format("cannot unlink '%1%'") % path);
-        }
-      }
-    }
-  } catch (...) {
-    ignoreException();
-  }
-}
-
-void AutoDelete::cancel() { del = false; }
-
-void AutoDelete::reset(const Path& p, bool recursive) {
-  path = p;
-  this->recursive = recursive;
-  del = true;
-}
-
-//////////////////////////////////////////////////////////////////////
-
-AutoCloseFD::AutoCloseFD() : fd{-1} {}
-
-AutoCloseFD::AutoCloseFD(int fd) : fd{fd} {}
-
-AutoCloseFD::AutoCloseFD(AutoCloseFD&& that) : fd{that.fd} { that.fd = -1; }
-
-AutoCloseFD& AutoCloseFD::operator=(AutoCloseFD&& that) {
-  close();
-  fd = that.fd;
-  that.fd = -1;
-  return *this;
-}
-
-AutoCloseFD::~AutoCloseFD() {
-  try {
-    close();
-  } catch (...) {
-    ignoreException();
-  }
-}
-
-int AutoCloseFD::get() const { return fd; }
-
-void AutoCloseFD::close() {
-  if (fd != -1) {
-    if (::close(fd) == -1) { /* This should never happen. */
-      throw SysError(format("closing file descriptor %1%") % fd);
-    }
-  }
-}
-
-AutoCloseFD::operator bool() const { return fd != -1; }
-
-int AutoCloseFD::release() {
-  int oldFD = fd;
-  fd = -1;
-  return oldFD;
-}
-
-void Pipe::create() {
-  int fds[2];
-#if HAVE_PIPE2
-  if (pipe2(fds, O_CLOEXEC) != 0) {
-    throw SysError("creating pipe");
-  }
-#else
-  if (pipe(fds) != 0) {
-    throw SysError("creating pipe");
-  }
-  closeOnExec(fds[0]);
-  closeOnExec(fds[1]);
-#endif
-  readSide = AutoCloseFD(fds[0]);
-  writeSide = AutoCloseFD(fds[1]);
-}
-
-//////////////////////////////////////////////////////////////////////
-
-Pid::Pid() = default;
-
-Pid::Pid(pid_t pid) : pid(pid) {}
-
-Pid::~Pid() {
-  if (pid != -1) {
-    kill();
-  }
-}
-
-void Pid::operator=(pid_t pid) {
-  if (this->pid != -1 && this->pid != pid) {
-    kill();
-  }
-  this->pid = pid;
-  killSignal = SIGKILL;  // reset signal to default
-}
-
-Pid::operator pid_t() { return pid; }
-
-int Pid::kill() {
-  assert(pid != -1);
-
-  DLOG(INFO) << "killing process " << pid;
-
-  /* Send the requested signal to the child.  If it has its own
-     process group, send the signal to every process in the child
-     process group (which hopefully includes *all* its children). */
-  if (::kill(separatePG ? -pid : pid, killSignal) != 0) {
-    LOG(ERROR) << SysError("killing process %d", pid).msg();
-  }
-
-  return wait();
-}
-
-int Pid::wait() {
-  assert(pid != -1);
-  while (true) {
-    int status;
-    int res = waitpid(pid, &status, 0);
-    if (res == pid) {
-      pid = -1;
-      return status;
-    }
-    if (errno != EINTR) {
-      throw SysError("cannot get child exit status");
-    }
-    checkInterrupt();
-  }
-}
-
-void Pid::setSeparatePG(bool separatePG) { this->separatePG = separatePG; }
-
-void Pid::setKillSignal(int signal) { this->killSignal = signal; }
-
-pid_t Pid::release() {
-  pid_t p = pid;
-  pid = -1;
-  return p;
-}
-
-void killUser(uid_t uid) {
-  DLOG(INFO) << "killing all processes running under UID " << uid;
-
-  assert(uid != 0); /* just to be safe... */
-
-  /* The system call kill(-1, sig) sends the signal `sig' to all
-     users to which the current process can send signals.  So we
-     fork a process, switch to uid, and send a mass kill. */
-
-  ProcessOptions options;
-
-  Pid pid(startProcess(
-      [&]() {
-        if (setuid(uid) == -1) {
-          throw SysError("setting uid");
-        }
-
-        while (true) {
-          if (kill(-1, SIGKILL) == 0) {
-            break;
-          }
-          if (errno == ESRCH) {
-            break;
-          } /* no more processes */
-          if (errno != EINTR) {
-            throw SysError(format("cannot kill processes for uid '%1%'") % uid);
-          }
-        }
-
-        _exit(0);
-      },
-      options));
-
-  int status = pid.wait();
-  if (status != 0) {
-    throw Error(format("cannot kill processes for uid '%1%': %2%") % uid %
-                statusToString(status));
-  }
-
-  /* !!! We should really do some check to make sure that there are
-     no processes left running under `uid', but there is no portable
-     way to do so (I think).  The most reliable way may be `ps -eo
-     uid | grep -q $uid'. */
-}
-
-//////////////////////////////////////////////////////////////////////
-
-/*
- * Please note that it is not legal for this function to call vfork().  If the
- * process created by vfork() returns from the function in which vfork() was
- * called, or calls any other function before successfully calling _exit() or
- * one of the exec*() family of functions, the behavior is undefined.
- */
-static pid_t doFork(const std::function<void()>& fun) __attribute__((noinline));
-static pid_t doFork(const std::function<void()>& fun) {
-#ifdef __linux__
-  // TODO(kanepyork): call clone() instead for faster forking
-#endif
-
-  pid_t pid = fork();
-  if (pid != 0) {
-    return pid;
-  }
-  fun();
-  abort();
-}
-
-pid_t startProcess(std::function<void()> fun, const ProcessOptions& options) {
-  auto wrapper = [&]() {
-    try {
-#if __linux__
-      if (options.dieWithParent && prctl(PR_SET_PDEATHSIG, SIGKILL) == -1) {
-        throw SysError("setting death signal");
-      }
-#endif
-      restoreAffinity();
-      fun();
-    } catch (std::exception& e) {
-      try {
-        LOG(ERROR) << options.errorPrefix << e.what();
-      } catch (...) {
-      }
-    } catch (...) {
-    }
-    if (options.runExitHandlers) {
-      exit(1);
-    } else {
-      _exit(1);
-    }
-  };
-
-  pid_t pid = doFork(wrapper);
-  if (pid == -1) {
-    throw SysError("unable to fork");
-  }
-
-  return pid;
-}
-
-std::vector<char*> stringsToCharPtrs(const Strings& ss) {
-  std::vector<char*> res;
-  for (auto& s : ss) {
-    res.push_back(const_cast<char*>(s.c_str()));
-  }
-  res.push_back(nullptr);
-  return res;
-}
-
-std::string runProgram(const Path& program, bool searchPath,
-                       const Strings& args,
-                       const std::optional<std::string>& input) {
-  RunOptions opts(program, args);
-  opts.searchPath = searchPath;
-  opts.input = input;
-
-  auto res = runProgram(opts);
-
-  if (!statusOk(res.first)) {
-    throw ExecError(res.first, fmt("program '%1%' %2%", program,
-                                   statusToString(res.first)));
-  }
-
-  return res.second;
-}
-
-std::pair<int, std::string> runProgram(const RunOptions& options_) {
-  RunOptions options(options_);
-  StringSink sink;
-  options.standardOut = &sink;
-
-  int status = 0;
-
-  try {
-    runProgram2(options);
-  } catch (ExecError& e) {
-    status = e.status;
-  }
-
-  return {status, std::move(*sink.s)};
-}
-
-void runProgram2(const RunOptions& options) {
-  checkInterrupt();
-
-  assert(!(options.standardIn && options.input));
-
-  std::unique_ptr<Source> source_;
-  Source* source = options.standardIn;
-
-  if (options.input) {
-    source_ = std::make_unique<StringSource>(*options.input);
-    source = source_.get();
-  }
-
-  /* Create a pipe. */
-  Pipe out;
-  Pipe in;
-  if (options.standardOut != nullptr) {
-    out.create();
-  }
-  if (source != nullptr) {
-    in.create();
-  }
-
-  ProcessOptions processOptions;
-
-  /* Fork. */
-  Pid pid(startProcess(
-      [&]() {
-        if (options.environment) {
-          replaceEnv(*options.environment);
-        }
-        if ((options.standardOut != nullptr) &&
-            dup2(out.writeSide.get(), STDOUT_FILENO) == -1) {
-          throw SysError("dupping stdout");
-        }
-        if (options.mergeStderrToStdout) {
-          if (dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
-            throw SysError("cannot dup stdout into stderr");
-          }
-        }
-        if ((source != nullptr) &&
-            dup2(in.readSide.get(), STDIN_FILENO) == -1) {
-          throw SysError("dupping stdin");
-        }
-
-        if (options.chdir && chdir((*options.chdir).c_str()) == -1) {
-          throw SysError("chdir failed");
-        }
-        if (options.gid && setgid(*options.gid) == -1) {
-          throw SysError("setgid failed");
-        }
-        /* Drop all other groups if we're setgid. */
-        if (options.gid && setgroups(0, nullptr) == -1) {
-          throw SysError("setgroups failed");
-        }
-        if (options.uid && setuid(*options.uid) == -1) {
-          throw SysError("setuid failed");
-        }
-
-        Strings args_(options.args);
-        args_.push_front(options.program);
-
-        restoreSignals();
-
-        if (options.searchPath) {
-          execvp(options.program.c_str(), stringsToCharPtrs(args_).data());
-        } else {
-          execv(options.program.c_str(), stringsToCharPtrs(args_).data());
-        }
-
-        throw SysError("executing '%1%'", options.program);
-      },
-      processOptions));
-
-  out.writeSide = AutoCloseFD(-1);
-
-  std::thread writerThread;
-
-  std::promise<void> promise;
-
-  Finally doJoin([&]() {
-    if (writerThread.joinable()) {
-      writerThread.join();
-    }
-  });
-
-  if (source != nullptr) {
-    in.readSide = AutoCloseFD(-1);
-    writerThread = std::thread([&]() {
-      try {
-        std::vector<unsigned char> buf(8 * 1024);
-        while (true) {
-          size_t n;
-          try {
-            n = source->read(buf.data(), buf.size());
-          } catch (EndOfFile&) {
-            break;
-          }
-          writeFull(in.writeSide.get(), buf.data(), n);
-        }
-        promise.set_value();
-      } catch (...) {
-        promise.set_exception(std::current_exception());
-      }
-      in.writeSide = AutoCloseFD(-1);
-    });
-  }
-
-  if (options.standardOut != nullptr) {
-    drainFD(out.readSide.get(), *options.standardOut);
-  }
-
-  /* Wait for the child to finish. */
-  int status = pid.wait();
-
-  /* Wait for the writer thread to finish. */
-  if (source != nullptr) {
-    promise.get_future().get();
-  }
-
-  if (status != 0) {
-    throw ExecError(status, fmt("program '%1%' %2%", options.program,
-                                statusToString(status)));
-  }
-}
-
-void closeMostFDs(const std::set<int>& exceptions) {
-#if __linux__
-  try {
-    for (auto& s : readDirectory("/proc/self/fd")) {
-      auto fd = std::stoi(s.name);
-      if (exceptions.count(fd) == 0u) {
-        DLOG(INFO) << "closing leaked FD " << fd;
-        close(fd);
-      }
-    }
-    return;
-  } catch (SysError&) {
-  }
-#endif
-
-  int maxFD = 0;
-  maxFD = sysconf(_SC_OPEN_MAX);
-  for (int fd = 0; fd < maxFD; ++fd) {
-    if (exceptions.count(fd) == 0u) {
-      close(fd);
-    } /* ignore result */
-  }
-}
-
-void closeOnExec(int fd) {
-  int prev;
-  if ((prev = fcntl(fd, F_GETFD, 0)) == -1 ||
-      fcntl(fd, F_SETFD, prev | FD_CLOEXEC) == -1) {
-    throw SysError("setting close-on-exec flag");
-  }
-}
-
-//////////////////////////////////////////////////////////////////////
-
-bool _isInterrupted = false;
-
-static thread_local bool interruptThrown = false;
-thread_local std::function<bool()> interruptCheck;
-
-void setInterruptThrown() { interruptThrown = true; }
-
-void _interrupted() {
-  /* Block user interrupts while an exception is being handled.
-     Throwing an exception while another exception is being handled
-     kills the program! */
-  if (!interruptThrown && (std::uncaught_exceptions() == 0)) {
-    interruptThrown = true;
-    throw Interrupted("interrupted by the user");
-  }
-}
-
-//////////////////////////////////////////////////////////////////////
-
-std::string concatStringsSep(const std::string& sep, const Strings& ss) {
-  std::string s;
-  for (auto& i : ss) {
-    if (!s.empty()) {
-      s += sep;
-    }
-    s += i;
-  }
-  return s;
-}
-
-std::string concatStringsSep(const std::string& sep, const StringSet& ss) {
-  std::string s;
-  for (auto& i : ss) {
-    if (!s.empty()) {
-      s += sep;
-    }
-    s += i;
-  }
-  return s;
-}
-
-std::string replaceStrings(const std::string& s, const std::string& from,
-                           const std::string& to) {
-  if (from.empty()) {
-    return s;
-  }
-  std::string res = s;
-  size_t pos = 0;
-  while ((pos = res.find(from, pos)) != std::string::npos) {
-    res.replace(pos, from.size(), to);
-    pos += to.size();
-  }
-  return res;
-}
-
-std::string statusToString(int status) {
-  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-    if (WIFEXITED(status)) {
-      return (format("failed with exit code %1%") % WEXITSTATUS(status)).str();
-    }
-    if (WIFSIGNALED(status)) {
-      int sig = WTERMSIG(status);
-#if HAVE_STRSIGNAL
-      const char* description = strsignal(sig);
-      return (format("failed due to signal %1% (%2%)") % sig % description)
-          .str();
-#else
-      return (format("failed due to signal %1%") % sig).str();
-#endif
-    } else {
-      return "died abnormally";
-    }
-  } else {
-    return "succeeded";
-  }
-}
-
-bool statusOk(int status) {
-  return WIFEXITED(status) && WEXITSTATUS(status) == 0;
-}
-
-std::string toLower(const std::string& s) {
-  std::string r(s);
-  for (auto& c : r) {
-    c = std::tolower(c);
-  }
-  return r;
-}
-
-std::string shellEscape(const std::string& s) {
-  std::string r = "'";
-  for (auto& i : s) {
-    if (i == '\'') {
-      r += "'\\''";
-    } else {
-      r += i;
-    }
-  }
-  r += '\'';
-  return r;
-}
-
-void ignoreException() {
-  try {
-    throw;
-  } catch (std::exception& e) {
-    LOG(ERROR) << "error (ignored): " << e.what();
-  }
-}
-
-std::string filterANSIEscapes(const std::string& s, bool filterAll,
-                              unsigned int width) {
-  std::string t;
-  std::string e;
-  size_t w = 0;
-  auto i = s.begin();
-
-  while (w < static_cast<size_t>(width) && i != s.end()) {
-    if (*i == '\e') {
-      std::string e;
-      e += *i++;
-      char last = 0;
-
-      if (i != s.end() && *i == '[') {
-        e += *i++;
-        // eat parameter bytes
-        while (i != s.end() && *i >= 0x30 && *i <= 0x3f) {
-          e += *i++;
-        }
-        // eat intermediate bytes
-        while (i != s.end() && *i >= 0x20 && *i <= 0x2f) {
-          e += *i++;
-        }
-        // eat final byte
-        if (i != s.end() && *i >= 0x40 && *i <= 0x7e) {
-          e += last = *i++;
-        }
-      } else {
-        if (i != s.end() && *i >= 0x40 && *i <= 0x5f) {
-          e += *i++;
-        }
-      }
-
-      if (!filterAll && last == 'm') {
-        t += e;
-      }
-    }
-
-    else if (*i == '\t') {
-      i++;
-      t += ' ';
-      w++;
-      while (w < static_cast<size_t>(width) && ((w % 8) != 0u)) {
-        t += ' ';
-        w++;
-      }
-    }
-
-    else if (*i == '\r') {
-      // do nothing for now
-      i++;
-
-    } else {
-      t += *i++;
-      w++;
-    }
-  }
-
-  return t;
-}
-
-void callFailure(const std::function<void(std::exception_ptr exc)>& failure,
-                 const std::exception_ptr& exc) {
-  try {
-    failure(exc);
-  } catch (std::exception& e) {
-    LOG(ERROR) << "uncaught exception: " << e.what();
-    abort();
-  }
-}
-
-static Sync<std::pair<unsigned short, unsigned short>> windowSize{{0, 0}};
-
-static void updateWindowSize() {
-  struct winsize ws;
-  if (ioctl(2, TIOCGWINSZ, &ws) == 0) {
-    auto windowSize_(windowSize.lock());
-    windowSize_->first = ws.ws_row;
-    windowSize_->second = ws.ws_col;
-  }
-}
-
-std::pair<unsigned short, unsigned short> getWindowSize() {
-  return *windowSize.lock();
-}
-
-static Sync<std::list<std::function<void()>>> _interruptCallbacks;
-
-static void signalHandlerThread(sigset_t set) {
-  while (true) {
-    int signal = 0;
-    sigwait(&set, &signal);
-
-    if (signal == SIGINT || signal == SIGTERM || signal == SIGHUP) {
-      triggerInterrupt();
-
-    } else if (signal == SIGWINCH) {
-      updateWindowSize();
-    }
-  }
-}
-
-void triggerInterrupt() {
-  _isInterrupted = true;
-
-  {
-    auto interruptCallbacks(_interruptCallbacks.lock());
-    for (auto& callback : *interruptCallbacks) {
-      try {
-        callback();
-      } catch (...) {
-        ignoreException();
-      }
-    }
-  }
-}
-
-static sigset_t savedSignalMask;
-
-void startSignalHandlerThread() {
-  updateWindowSize();
-
-  if (sigprocmask(SIG_BLOCK, nullptr, &savedSignalMask) != 0) {
-    throw SysError("quering signal mask");
-  }
-
-  sigset_t set;
-  sigemptyset(&set);
-  sigaddset(&set, SIGINT);
-  sigaddset(&set, SIGTERM);
-  sigaddset(&set, SIGHUP);
-  sigaddset(&set, SIGPIPE);
-  sigaddset(&set, SIGWINCH);
-  if (pthread_sigmask(SIG_BLOCK, &set, nullptr) != 0) {
-    throw SysError("blocking signals");
-  }
-
-  std::thread(signalHandlerThread, set).detach();
-}
-
-void restoreSignals() {
-  if (sigprocmask(SIG_SETMASK, &savedSignalMask, nullptr) != 0) {
-    throw SysError("restoring signals");
-  }
-}
-
-/* RAII helper to automatically deregister a callback. */
-struct InterruptCallbackImpl : InterruptCallback {
-  std::list<std::function<void()>>::iterator it;
-  ~InterruptCallbackImpl() override { _interruptCallbacks.lock()->erase(it); }
-};
-
-std::unique_ptr<InterruptCallback> createInterruptCallback(
-    const std::function<void()>& callback) {
-  auto interruptCallbacks(_interruptCallbacks.lock());
-  interruptCallbacks->push_back(callback);
-
-  auto res = std::make_unique<InterruptCallbackImpl>();
-  res->it = interruptCallbacks->end();
-  res->it--;
-
-  return std::unique_ptr<InterruptCallback>(res.release());
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/util.hh b/third_party/nix/src/libutil/util.hh
deleted file mode 100644
index b3349c4f39c4..000000000000
--- a/third_party/nix/src/libutil/util.hh
+++ /dev/null
@@ -1,476 +0,0 @@
-#pragma once
-
-#include <cstdio>
-#include <functional>
-#include <future>
-#include <limits>
-#include <map>
-#include <optional>
-#include <sstream>
-
-#include <absl/strings/string_view.h>
-#include <dirent.h>
-#include <signal.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#include "libutil/types.hh"
-
-namespace nix {
-
-struct Sink;
-struct Source;
-
-/* The system for which Nix is compiled. */
-extern const std::string nativeSystem;
-
-/* Return an environment variable. */
-std::optional<std::string> getEnv(const std::string& key);
-
-/* Get the entire environment. */
-std::map<std::string, std::string> getEnv();
-
-/* Clear the environment. */
-void clearEnv();
-
-/* Return an absolutized path, resolving paths relative to the
-   specified directory, or the current directory otherwise.  The path
-   is also canonicalised. */
-Path absPath(Path path, Path dir = "");
-
-/* Canonicalise a path by removing all `.' or `..' components and
-   double or trailing slashes.  Optionally resolves all symlink
-   components such that each component of the resulting path is *not*
-   a symbolic link. */
-Path canonPath(const Path& path, bool resolveSymlinks = false);
-
-/* Return the directory part of the given canonical path, i.e.,
-   everything before the final `/'.  If the path is the root or an
-   immediate child thereof (e.g., `/foo'), this means an empty string
-   is returned. */
-Path dirOf(absl::string_view path);
-
-/* Return the base name of the given canonical path, i.e., everything
-   following the final `/'. */
-std::string baseNameOf(const Path& path);
-
-/* Check whether 'path' is a descendant of 'dir'. */
-bool isInDir(const Path& path, const Path& dir);
-
-/* Check whether 'path' is equal to 'dir' or a descendant of 'dir'. */
-bool isDirOrInDir(const Path& path, const Path& dir);
-
-/* Get status of `path'. */
-struct stat lstat(const Path& path);
-
-/* Return true iff the given path exists. */
-bool pathExists(const Path& path);
-
-/* Read the contents (target) of a symbolic link.  The result is not
-   in any way canonicalised. */
-Path readLink(const Path& path);
-
-bool isLink(const Path& path);
-
-/* Read the contents of a directory.  The entries `.' and `..' are
-   removed. */
-struct DirEntry {
-  std::string name;
-  ino_t ino;
-  unsigned char type;  // one of DT_*
-  DirEntry(const std::string& name, ino_t ino, unsigned char type)
-      : name(name), ino(ino), type(type) {}
-};
-
-typedef std::vector<DirEntry> DirEntries;
-
-DirEntries readDirectory(const Path& path);
-
-unsigned char getFileType(const Path& path);
-
-/* Read the contents of a file into a string. */
-std::string readFile(int fd);
-std::string readFile(absl::string_view path, bool drain = false);
-void readFile(absl::string_view path, Sink& sink);
-
-/* Write a string to a file. */
-void writeFile(const Path& path, const std::string& s, mode_t mode = 0666);
-
-void writeFile(const Path& path, Source& source, mode_t mode = 0666);
-
-/* Read a line from a file descriptor. */
-std::string readLine(int fd);
-
-/* Write a line to a file descriptor. */
-void writeLine(int fd, std::string s);
-
-/* Delete a path; i.e., in the case of a directory, it is deleted
-   recursively. It's not an error if the path does not exist. The
-   second variant returns the number of bytes and blocks freed. */
-void deletePath(const Path& path);
-
-void deletePath(const Path& path, unsigned long long& bytesFreed);
-
-/* Create a temporary directory. */
-Path createTempDir(const Path& tmpRoot = "", const Path& prefix = "nix",
-                   bool includePid = true, bool useGlobalCounter = true,
-                   mode_t mode = 0755);
-
-std::string getUserName();
-
-/* Return $HOME or the user's home directory from /etc/passwd. */
-Path getHome();
-
-/* Return $XDG_CACHE_HOME or $HOME/.cache. */
-Path getCacheDir();
-
-/* Return $XDG_CONFIG_HOME or $HOME/.config. */
-Path getConfigDir();
-
-/* Return the directories to search for user configuration files */
-std::vector<Path> getConfigDirs();
-
-/* Return $XDG_DATA_HOME or $HOME/.local/share. */
-Path getDataDir();
-
-/* Create a directory and all its parents, if necessary.  Returns the
-   list of created directories, in order of creation. */
-Paths createDirs(const Path& path);
-
-/* Create a symlink. */
-void createSymlink(const Path& target, const Path& link);
-
-/* Atomically create or replace a symlink. */
-void replaceSymlink(const Path& target, const Path& link);
-
-/* Wrappers arount read()/write() that read/write exactly the
-   requested number of bytes. */
-void readFull(int fd, unsigned char* buf, size_t count);
-void writeFull(int fd, const unsigned char* buf, size_t count,
-               bool allowInterrupts = true);
-void writeFull(int fd, const std::string& s, bool allowInterrupts = true);
-
-MakeError(EndOfFile, Error);
-
-/* Read a file descriptor until EOF occurs. */
-std::string drainFD(int fd, bool block = true);
-
-void drainFD(int fd, Sink& sink, bool block = true);
-
-/* Automatic cleanup of resources. */
-
-class AutoDelete {
-  Path path;
-  bool del;
-  bool recursive;
-
- public:
-  AutoDelete();
-  explicit AutoDelete(Path p, bool recursive = true);
-  ~AutoDelete();
-  void cancel();
-  void reset(const Path& p, bool recursive = true);
-  explicit operator Path() const { return path; }
-};
-
-class AutoCloseFD {
-  int fd;
-  void close();
-
- public:
-  AutoCloseFD();
-  explicit AutoCloseFD(int fd);
-  AutoCloseFD(const AutoCloseFD& fd) = delete;
-  AutoCloseFD(AutoCloseFD&& that);
-  ~AutoCloseFD();
-  AutoCloseFD& operator=(const AutoCloseFD& fd) = delete;
-  AutoCloseFD& operator=(AutoCloseFD&& that);
-  int get() const;
-  explicit operator bool() const;
-  int release();
-};
-
-class Pipe {
- public:
-  AutoCloseFD readSide, writeSide;
-  void create();
-};
-
-struct DIRDeleter {
-  void operator()(DIR* dir) const { closedir(dir); }
-};
-
-using AutoCloseDir = std::unique_ptr<DIR, DIRDeleter>;
-
-class Pid {
-  pid_t pid = -1;
-  bool separatePG = false;
-  int killSignal = SIGKILL;
-
- public:
-  Pid();
-  explicit Pid(pid_t pid);
-  ~Pid();
-  void operator=(pid_t pid);
-  explicit operator pid_t();
-  int kill();
-  int wait();
-
-  void setSeparatePG(bool separatePG);
-  void setKillSignal(int signal);
-  pid_t release();
-
-  friend bool operator==(const Pid& lhs, const Pid& rhs) {
-    return lhs.pid == rhs.pid;
-  }
-
-  friend bool operator!=(const Pid& lhs, const Pid& rhs) {
-    return !(lhs == rhs);
-  }
-};
-
-/* Kill all processes running under the specified uid by sending them
-   a SIGKILL. */
-void killUser(uid_t uid);
-
-/* Fork a process that runs the given function, and return the child
-   pid to the caller. */
-struct ProcessOptions {
-  std::string errorPrefix = "error: ";
-  bool dieWithParent = true;
-  bool runExitHandlers = false;
-};
-
-pid_t startProcess(std::function<void()> fun,
-                   const ProcessOptions& options = ProcessOptions());
-
-/* Run a program and return its stdout in a string (i.e., like the
-   shell backtick operator). */
-std::string runProgram(const Path& program, bool searchPath = false,
-                       const Strings& args = Strings(),
-                       const std::optional<std::string>& input = {});
-
-struct RunOptions {
-  std::optional<uid_t> uid;
-  std::optional<uid_t> gid;
-  std::optional<Path> chdir;
-  std::optional<std::map<std::string, std::string>> environment;
-  Path program;
-  bool searchPath = true;
-  Strings args;
-  std::optional<std::string> input;
-  Source* standardIn = nullptr;
-  Sink* standardOut = nullptr;
-  bool mergeStderrToStdout = false;
-  bool _killStderr = false;
-
-  RunOptions(const Path& program, const Strings& args)
-      : program(program), args(args){};
-
-  RunOptions& killStderr(bool v) {
-    _killStderr = true;
-    return *this;
-  }
-};
-
-std::pair<int, std::string> runProgram(const RunOptions& options);
-
-void runProgram2(const RunOptions& options);
-
-class ExecError : public Error {
- public:
-  int status;
-
-  template <typename... Args>
-  explicit ExecError(int status, Args... args)
-      : Error(args...), status(status) {}
-};
-
-/* Convert a list of strings to a null-terminated vector of char
-   *'s. The result must not be accessed beyond the lifetime of the
-   list of strings. */
-std::vector<char*> stringsToCharPtrs(const Strings& ss);
-
-/* Close all file descriptors except those listed in the given set.
-   Good practice in child processes. */
-void closeMostFDs(const std::set<int>& exceptions);
-
-/* Set the close-on-exec flag for the given file descriptor. */
-void closeOnExec(int fd);
-
-/* User interruption. */
-
-extern bool _isInterrupted;
-
-extern thread_local std::function<bool()> interruptCheck;
-
-void setInterruptThrown();
-
-void _interrupted();
-
-void inline checkInterrupt() {
-  if (_isInterrupted || (interruptCheck && interruptCheck())) {
-    _interrupted();
-  }
-}
-
-MakeError(Interrupted, BaseError);
-
-MakeError(FormatError, Error);
-
-/* Concatenate the given strings with a separator between the
-   elements. */
-std::string concatStringsSep(const std::string& sep, const Strings& ss);
-std::string concatStringsSep(const std::string& sep, const StringSet& ss);
-
-/* Replace all occurrences of a string inside another string. */
-std::string replaceStrings(const std::string& s, const std::string& from,
-                           const std::string& to);
-
-/* Convert the exit status of a child as returned by wait() into an
-   error string. */
-std::string statusToString(int status);
-
-bool statusOk(int status);
-
-/* Parse a string into a float. */
-template <class N>
-bool string2Float(const std::string& s, N& n) {
-  std::istringstream str(s);
-  str >> n;
-  return str && str.get() == EOF;
-}
-
-/* Convert a string to lower case. */
-std::string toLower(const std::string& s);
-
-/* Escape a string as a shell word. */
-std::string shellEscape(const std::string& s);
-
-/* Exception handling in destructors: print an error message, then
-   ignore the exception. */
-void ignoreException();
-
-/* Some ANSI escape sequences. */
-#define ANSI_NORMAL "\e[0m"
-#define ANSI_BOLD "\e[1m"
-#define ANSI_FAINT "\e[2m"
-#define ANSI_RED "\e[31;1m"
-#define ANSI_GREEN "\e[32;1m"
-#define ANSI_BLUE "\e[34;1m"
-
-/* Truncate a string to 'width' printable characters. If 'filterAll'
-   is true, all ANSI escape sequences are filtered out. Otherwise,
-   some escape sequences (such as colour setting) are copied but not
-   included in the character count. Also, tabs are expanded to
-   spaces. */
-std::string filterANSIEscapes(
-    const std::string& s, bool filterAll = false,
-    unsigned int width = std::numeric_limits<unsigned int>::max());
-
-/* Get a value for the specified key from an associate container, or a
-   default value if the key doesn't exist. */
-template <class T>
-std::string get(const T& map, const std::string& key,
-                const std::string& def = "") {
-  auto i = map.find(key);
-  return i == map.end() ? def : i->second;
-}
-
-/* A callback is a wrapper around a lambda that accepts a valid of
-   type T or an exception. (We abuse std::future<T> to pass the value or
-   exception.) */
-template <typename T>
-class Callback {
-  std::function<void(std::future<T>)> fun;
-  std::atomic_flag done = ATOMIC_FLAG_INIT;
-
- public:
-  explicit Callback(std::function<void(std::future<T>)> fun) : fun(fun) {}
-
-  Callback(Callback&& callback) : fun(std::move(callback.fun)) {
-    auto prev = callback.done.test_and_set();
-    if (prev) {
-      done.test_and_set();
-    }
-  }
-
-// The unused-variable assert is disabled in this block because the
-// `prev` variables are only used in debug mode (in the asserts).
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wunused-variable"
-
-  void operator()(T&& t) noexcept {
-    auto prev = done.test_and_set();
-    assert(!prev);
-    std::promise<T> promise;
-    promise.set_value(std::move(t));
-    fun(promise.get_future());
-  }
-
-  void rethrow(
-      const std::exception_ptr& exc = std::current_exception()) noexcept {
-    auto prev = done.test_and_set();
-    assert(!prev);
-    std::promise<T> promise;
-    promise.set_exception(exc);
-    fun(promise.get_future());
-  }
-
-#pragma clang diagnostic pop
-};
-
-/* Start a thread that handles various signals. Also block those signals
-   on the current thread (and thus any threads created by it). */
-void startSignalHandlerThread();
-
-/* Restore default signal handling. */
-void restoreSignals();
-
-struct InterruptCallback {
-  virtual ~InterruptCallback(){};
-};
-
-/* Register a function that gets called on SIGINT (in a non-signal
-   context). */
-std::unique_ptr<InterruptCallback> createInterruptCallback(
-    const std::function<void()>& callback);
-
-void triggerInterrupt();
-
-/* A RAII class that causes the current thread to receive SIGUSR1 when
-   the signal handler thread receives SIGINT. That is, this allows
-   SIGINT to be multiplexed to multiple threads. */
-struct ReceiveInterrupts {
-  pthread_t target;
-  std::unique_ptr<InterruptCallback> callback;
-
-  ReceiveInterrupts()
-      : target(pthread_self()), callback(createInterruptCallback([&]() {
-          pthread_kill(target, SIGUSR1);
-        })) {}
-};
-
-/* A RAII helper that increments a counter on construction and
-   decrements it on destruction. */
-template <typename T>
-struct MaintainCount {
-  T& counter;
-  long delta;
-  explicit MaintainCount(T& counter, long delta = 1)
-      : counter(counter), delta(delta) {
-    counter += delta;
-  }
-  ~MaintainCount() { counter -= delta; }
-};
-
-/* Return the number of rows and columns of the terminal. */
-std::pair<unsigned short, unsigned short> getWindowSize();
-
-/* Used in various places. */
-using PathFilter = std::function<bool(const Path&)>;
-
-extern PathFilter defaultPathFilter;
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/visitor.hh b/third_party/nix/src/libutil/visitor.hh
deleted file mode 100644
index bf1d665af77f..000000000000
--- a/third_party/nix/src/libutil/visitor.hh
+++ /dev/null
@@ -1,19 +0,0 @@
-#pragma once
-
-namespace nix::util {
-
-// Helper class used for visiting std::variants by creating a variadic
-// list of lambda expressions that delegates calls to each of the
-// callables.
-//
-// See e.g.
-// https://dev.to/tmr232/that-overloaded-trick-overloading-lambdas-in-c17
-template <class... Ts>
-struct overloaded : Ts... {
-  using Ts::operator()...;
-};
-
-template <class... Ts>
-overloaded(Ts...) -> overloaded<Ts...>;
-
-}  // namespace nix::util
diff --git a/third_party/nix/src/libutil/xml-writer.cc b/third_party/nix/src/libutil/xml-writer.cc
deleted file mode 100644
index 8274ed769eb4..000000000000
--- a/third_party/nix/src/libutil/xml-writer.cc
+++ /dev/null
@@ -1,93 +0,0 @@
-#include "libutil/xml-writer.hh"
-
-#include <cassert>
-
-namespace nix {
-
-XMLWriter::XMLWriter(bool indent, std::ostream& output)
-    : output(output), indent(indent) {
-  output << "<?xml version='1.0' encoding='utf-8'?>" << std::endl;
-  closed = false;
-}
-
-XMLWriter::~XMLWriter() { close(); }
-
-void XMLWriter::close() {
-  if (closed) {
-    return;
-  }
-  while (!pendingElems.empty()) {
-    closeElement();
-  }
-  closed = true;
-}
-
-void XMLWriter::indent_(size_t depth) {
-  if (!indent) {
-    return;
-  }
-  output << std::string(depth * 2, ' ');
-}
-
-void XMLWriter::openElement(const std::string& name, const XMLAttrs& attrs) {
-  assert(!closed);
-  indent_(pendingElems.size());
-  output << "<" << name;
-  writeAttrs(attrs);
-  output << ">";
-  if (indent) {
-    output << std::endl;
-  }
-  pendingElems.push_back(name);
-}
-
-void XMLWriter::closeElement() {
-  assert(!pendingElems.empty());
-  indent_(pendingElems.size() - 1);
-  output << "</" << pendingElems.back() << ">";
-  if (indent) {
-    output << std::endl;
-  }
-  pendingElems.pop_back();
-  if (pendingElems.empty()) {
-    closed = true;
-  }
-}
-
-void XMLWriter::writeEmptyElement(const std::string& name,
-                                  const XMLAttrs& attrs) {
-  assert(!closed);
-  indent_(pendingElems.size());
-  output << "<" << name;
-  writeAttrs(attrs);
-  output << " />";
-  if (indent) {
-    output << std::endl;
-  }
-}
-
-void XMLWriter::writeAttrs(const XMLAttrs& attrs) {
-  for (auto& i : attrs) {
-    output << " " << i.first << "=\"";
-    for (char c : i.second) {
-      if (c == '"') {
-        output << "&quot;";
-      } else if (c == '<') {
-        output << "&lt;";
-      } else if (c == '>') {
-        output << "&gt;";
-      } else if (c == '&') {
-        output << "&amp;";
-        /* Escape newlines to prevent attribute normalisation (see
-           XML spec, section 3.3.3. */
-      } else if (c == '\n') {
-        output << "&#xA;";
-      } else {
-        output << c;
-      }
-    }
-    output << "\"";
-  }
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libutil/xml-writer.hh b/third_party/nix/src/libutil/xml-writer.hh
deleted file mode 100644
index d6f7cddb35ac..000000000000
--- a/third_party/nix/src/libutil/xml-writer.hh
+++ /dev/null
@@ -1,52 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include <list>
-#include <map>
-#include <string>
-
-namespace nix {
-
-typedef std::map<std::string, std::string> XMLAttrs;
-
-class XMLWriter {
- private:
-  std::ostream& output;
-
-  bool indent;
-  bool closed;
-
-  std::list<std::string> pendingElems;
-
- public:
-  XMLWriter(bool indent, std::ostream& output);
-  ~XMLWriter();
-
-  void close();
-
-  void openElement(const std::string& name, const XMLAttrs& attrs = XMLAttrs());
-  void closeElement();
-
-  void writeEmptyElement(const std::string& name,
-                         const XMLAttrs& attrs = XMLAttrs());
-
- private:
-  void writeAttrs(const XMLAttrs& attrs);
-
-  void indent_(size_t depth);
-};
-
-class XMLOpenElement {
- private:
-  XMLWriter& writer;
-
- public:
-  XMLOpenElement(XMLWriter& writer, const std::string& name,
-                 const XMLAttrs& attrs = XMLAttrs())
-      : writer(writer) {
-    writer.openElement(name, attrs);
-  }
-  ~XMLOpenElement() { writer.closeElement(); }
-};
-
-}  // namespace nix