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>

7 files changed, 0 insertions, 720 deletions

diff --git a/third_party/nix/src/libmain/CMakeLists.txt b/third_party/nix/src/libmain/CMakeLists.txt
deleted file mode 100644
index a95128c1318f..000000000000
--- a/third_party/nix/src/libmain/CMakeLists.txt
+++ /dev/null
@@ -1,33 +0,0 @@
-# -*- mode: cmake; -*-
-add_library(nixmain SHARED)
-set_property(TARGET nixmain PROPERTY CXX_STANDARD 17)
-include_directories(${PROJECT_BINARY_DIR}) # for config.h
-target_include_directories(nixmain PUBLIC "${nix_SOURCE_DIR}/src")
-
-set(HEADER_FILES
-    common-args.hh
-    shared.hh
-)
-
-target_sources(nixmain
-  PUBLIC
-    ${HEADER_FILES}
-  PRIVATE
-    common-args.cc
-    shared.cc
-    stack.cc
-)
-
-target_link_libraries(nixmain
-  nixstore
-  nixutil
-
-  absl::strings
-  glog
-)
-
-configure_file("nix-main.pc.in" "${PROJECT_BINARY_DIR}/nix-main.pc" @ONLY)
-INSTALL(FILES "${PROJECT_BINARY_DIR}/nix-main.pc" DESTINATION "${PKGCONFIG_INSTALL_DIR}")
-
-INSTALL(FILES ${HEADER_FILES} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/nix/libmain)
-INSTALL(TARGETS nixmain DESTINATION ${CMAKE_INSTALL_LIBDIR})
diff --git a/third_party/nix/src/libmain/common-args.cc b/third_party/nix/src/libmain/common-args.cc
deleted file mode 100644
index 729e026f1990..000000000000
--- a/third_party/nix/src/libmain/common-args.cc
+++ /dev/null
@@ -1,56 +0,0 @@
-#include "libmain/common-args.hh"
-
-#include <glog/logging.h>
-
-#include "libstore/globals.hh"
-
-namespace nix {
-
-MixCommonArgs::MixCommonArgs(const std::string& programName)
-    : programName(programName) {
-  mkFlag()
-      .longName("verbose")
-      .shortName('v')
-      .description("increase verbosity level")
-      .handler([]() {
-        FLAGS_stderrthreshold = google::GLOG_INFO;
-        FLAGS_v += 1;
-      });
-
-  mkFlag()
-      .longName("quiet")
-      .description("silence all log output")
-      .handler([]() { FLAGS_stderrthreshold = google::GLOG_FATAL; });
-
-  mkFlag()
-      .longName("option")
-      .labels({"name", "value"})
-      .description("set a Nix configuration option (overriding nix.conf)")
-      .arity(2)
-      .handler([](std::vector<std::string> ss) {
-        try {
-          globalConfig.set(ss[0], ss[1]);
-        } catch (UsageError& e) {
-          LOG(WARNING) << e.what();
-        }
-      });
-
-  mkFlag()
-      .longName("max-jobs")
-      .shortName('j')
-      .label("jobs")
-      .description("maximum number of parallel builds")
-      .handler([=](const std::string& s) { settings.set("max-jobs", s); });
-
-  std::string cat = "config";
-  globalConfig.convertToArgs(*this, cat);
-
-  // Backward compatibility hack: nix-env already had a --system flag.
-  if (programName == "nix-env") {
-    longFlags.erase("system");
-  }
-
-  hiddenCategories.insert(cat);
-}
-
-}  // namespace nix
diff --git a/third_party/nix/src/libmain/common-args.hh b/third_party/nix/src/libmain/common-args.hh
deleted file mode 100644
index f1c7c8481323..000000000000
--- a/third_party/nix/src/libmain/common-args.hh
+++ /dev/null
@@ -1,27 +0,0 @@
-#pragma once
-
-#include "libutil/args.hh"
-
-namespace nix {
-
-struct MixCommonArgs : virtual Args {
-  std::string programName;
-  MixCommonArgs(const std::string& programName);
-};
-
-struct MixDryRun : virtual Args {
-  bool dryRun = false;
-
-  MixDryRun() {
-    mkFlag(0, "dry-run", "show what this command would do without doing it",
-           &dryRun);
-  }
-};
-
-struct MixJSON : virtual Args {
-  bool json = false;
-
-  MixJSON() { mkFlag(0, "json", "produce JSON output", &json); }
-};
-
-}  // namespace nix
diff --git a/third_party/nix/src/libmain/nix-main.pc.in b/third_party/nix/src/libmain/nix-main.pc.in
deleted file mode 100644
index 9876a3d1b7ae..000000000000
--- a/third_party/nix/src/libmain/nix-main.pc.in
+++ /dev/null
@@ -1,9 +0,0 @@
-prefix=@CMAKE_INSTALL_PREFIX@
-libdir=@CMAKE_INSTALL_FULL_LIBDIR@
-includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
-
-Name: Nix
-Description: Nix Package Manager
-Version: @PACKAGE_VERSION@
-Libs: -L${libdir} -lnixmain
-Cflags: -I${includedir}/nix
diff --git a/third_party/nix/src/libmain/shared.cc b/third_party/nix/src/libmain/shared.cc
deleted file mode 100644
index 331ea6b3a9d2..000000000000
--- a/third_party/nix/src/libmain/shared.cc
+++ /dev/null
@@ -1,386 +0,0 @@
-#include "libmain/shared.hh"
-
-#include <algorithm>
-#include <cctype>
-#include <csignal>
-#include <cstdlib>
-#include <exception>
-#include <iostream>
-#include <mutex>
-#include <utility>
-
-#include <glog/logging.h>
-#include <openssl/crypto.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <unistd.h>
-
-#include "libstore/globals.hh"
-#include "libstore/store-api.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-static bool gcWarning = true;
-
-void printGCWarning() {
-  if (!gcWarning) {
-    return;
-  }
-
-  static bool haveWarned = false;
-  if (!haveWarned) {
-    haveWarned = true;
-    LOG(WARNING) << "you did not specify '--add-root'; "
-                 << "the result might be removed by the garbage collector";
-  }
-}
-
-void printMissing(const ref<Store>& store, const PathSet& paths) {
-  unsigned long long downloadSize;
-  unsigned long long narSize;
-  PathSet willBuild;
-  PathSet willSubstitute;
-  PathSet unknown;
-  store->queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize,
-                      narSize);
-  printMissing(store, willBuild, willSubstitute, unknown, downloadSize,
-               narSize);
-}
-
-void printMissing(const ref<Store>& store, const PathSet& willBuild,
-                  const PathSet& willSubstitute, const PathSet& unknown,
-                  unsigned long long downloadSize, unsigned long long narSize) {
-  if (!willBuild.empty()) {
-    LOG(INFO) << "these derivations will be built:";
-    Paths sorted = store->topoSortPaths(willBuild);
-    reverse(sorted.begin(), sorted.end());
-    for (auto& i : sorted) {
-      LOG(INFO) << "  " << i;
-    }
-  }
-
-  if (!willSubstitute.empty()) {
-    LOG(INFO) << "these paths will be fetched ("
-              << (downloadSize / (1024.0 * 1024.0)) << " MiB download, "
-              << (narSize / (1024.0 * 1024.0)) << "MiB unpacked):";
-
-    for (auto& i : willSubstitute) {
-      LOG(INFO) << i;
-    }
-  }
-
-  if (!unknown.empty()) {
-    LOG(INFO) << "don't know how to build these paths"
-              << (settings.readOnlyMode
-                      ? " (may be caused by read-only store access)"
-                      : "")
-              << ":";
-
-    for (auto& i : unknown) {
-      LOG(INFO) << i;
-    }
-  }
-}
-
-std::string getArg(const std::string& opt, Strings::iterator& i,
-                   const Strings::iterator& end) {
-  ++i;
-  if (i == end) {
-    throw UsageError(format("'%1%' requires an argument") % opt);
-  }
-
-  return *i;
-}
-
-#if OPENSSL_VERSION_NUMBER < 0x10101000L
-/* OpenSSL is not thread-safe by default - it will randomly crash
-   unless the user supplies a mutex locking function. So let's do
-   that. */
-static std::vector<std::mutex> opensslLocks;
-
-static void opensslLockCallback(int mode, int type, const char* file,
-                                int line) {
-  if (mode & CRYPTO_LOCK)
-    opensslLocks[type].lock();
-  else
-    opensslLocks[type].unlock();
-}
-#endif
-
-static void sigHandler(int signo) {}
-
-void initNix() {
-  /* Turn on buffering for cerr. */
-#if HAVE_PUBSETBUF
-  static char buf[1024];
-  std::cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));
-#endif
-
-#if OPENSSL_VERSION_NUMBER < 0x10101000L
-  /* Initialise OpenSSL locking. */
-  opensslLocks = std::vector<std::mutex>(CRYPTO_num_locks());
-  CRYPTO_set_locking_callback(opensslLockCallback);
-#endif
-
-  loadConfFile();
-
-  startSignalHandlerThread();
-
-  /* Reset SIGCHLD to its default. */
-  struct sigaction act;
-  sigemptyset(&act.sa_mask);
-  act.sa_handler = SIG_DFL;
-  act.sa_flags = 0;
-  if (sigaction(SIGCHLD, &act, nullptr) != 0) {
-    throw SysError("resetting SIGCHLD");
-  }
-
-  /* Install a dummy SIGUSR1 handler for use with pthread_kill(). */
-  act.sa_handler = sigHandler;
-  if (sigaction(SIGUSR1, &act, nullptr) != 0) {
-    throw SysError("handling SIGUSR1");
-  }
-
-  /* Register a SIGSEGV handler to detect stack overflows. */
-  detectStackOverflow();
-
-  /* There is no privacy in the Nix system ;-)  At least not for
-     now.  In particular, store objects should be readable by
-     everybody. */
-  umask(0022);
-
-  /* Initialise the PRNG. */
-  struct timeval tv;
-  gettimeofday(&tv, nullptr);
-  srandom(tv.tv_usec);
-}
-
-LegacyArgs::LegacyArgs(
-    const std::string& programName,
-    std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-        parseArg)
-    : MixCommonArgs(programName), parseArg(std::move(parseArg)) {
-  mkFlag()
-      .longName("no-build-output")
-      .shortName('Q')
-      .description("do not show build output")
-      .set(&settings.verboseBuild, false);
-
-  mkFlag()
-      .longName("keep-failed")
-      .shortName('K')
-      .description("keep temporary directories of failed builds")
-      .set(&(bool&)settings.keepFailed, true);
-
-  mkFlag()
-      .longName("keep-going")
-      .shortName('k')
-      .description("keep going after a build fails")
-      .set(&(bool&)settings.keepGoing, true);
-
-  mkFlag()
-      .longName("fallback")
-      .description("build from source if substitution fails")
-      .set(&(bool&)settings.tryFallback, true);
-
-  auto intSettingAlias = [&](char shortName, const std::string& longName,
-                             const std::string& description,
-                             const std::string& dest) {
-    mkFlag<unsigned int>(shortName, longName, description, [=](unsigned int n) {
-      settings.set(dest, std::to_string(n));
-    });
-  };
-
-  intSettingAlias(0, "cores",
-                  "maximum number of CPU cores to use inside a build", "cores");
-  intSettingAlias(0, "max-silent-time",
-                  "number of seconds of silence before a build is killed",
-                  "max-silent-time");
-  intSettingAlias(0, "timeout", "number of seconds before a build is killed",
-                  "timeout");
-
-  mkFlag(0, "readonly-mode", "do not write to the Nix store",
-         &settings.readOnlyMode);
-
-  mkFlag(0, "no-gc-warning", "disable warning about not using '--add-root'",
-         &gcWarning, false);
-
-  mkFlag()
-      .longName("store")
-      .label("store-uri")
-      .description("URI of the Nix store to use")
-      .dest(&(std::string&)settings.storeUri);
-}
-
-bool LegacyArgs::processFlag(Strings::iterator& pos, Strings::iterator end) {
-  if (MixCommonArgs::processFlag(pos, end)) {
-    return true;
-  }
-  bool res = parseArg(pos, end);
-  if (res) {
-    ++pos;
-  }
-  return res;
-}
-
-bool LegacyArgs::processArgs(const Strings& args, bool finish) {
-  if (args.empty()) {
-    return true;
-  }
-  assert(args.size() == 1);
-  Strings ss(args);
-  auto pos = ss.begin();
-  if (!parseArg(pos, ss.end())) {
-    throw UsageError(format("unexpected argument '%1%'") % args.front());
-  }
-  return true;
-}
-
-void parseCmdLine(
-    int argc, char** argv,
-    std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-        parseArg) {
-  parseCmdLine(baseNameOf(argv[0]), argvToStrings(argc, argv),
-               std::move(parseArg));
-}
-
-void parseCmdLine(
-    const std::string& programName, const Strings& args,
-    std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-        parseArg) {
-  LegacyArgs(programName, std::move(parseArg)).parseCmdline(args);
-}
-
-void printVersion(const std::string& programName) {
-  std::cout << format("%1% (Tvix) %2%") % programName % nixVersion << std::endl;
-
-  // TODO(tazjin): figure out what the fuck this is
-  /*if (verbosity > lvlInfo) {
-    Strings cfg;
-#if HAVE_BOEHMGC
-    cfg.push_back("gc");
-#endif
-#if HAVE_SODIUM
-    cfg.push_back("signed-caches");
-#endif
-    std::cout << "Features: " << concatStringsSep(", ", cfg) << "\n";
-    std::cout << "Configuration file: " << settings.nixConfDir + "/nix.conf"
-              << "\n";
-    std::cout << "Store directory: " << settings.nixStore << "\n";
-    std::cout << "State directory: " << settings.nixStateDir << "\n";
-    } */
-  throw Exit();
-}
-
-void showManPage(const std::string& name) {
-  restoreSignals();
-  setenv("MANPATH", settings.nixManDir.c_str(), 1);
-  execlp("man", "man", name.c_str(), nullptr);
-  throw SysError(format("command 'man %1%' failed") % name.c_str());
-}
-
-int handleExceptions(const std::string& programName,
-                     const std::function<void()>& fun) {
-  ReceiveInterrupts receiveInterrupts;  // FIXME: need better place for this
-
-  std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
-  try {
-    try {
-      fun();
-    } catch (...) {
-      /* Subtle: we have to make sure that any `interrupted'
-         condition is discharged before we reach printMsg()
-         below, since otherwise it will throw an (uncaught)
-         exception. */
-      setInterruptThrown();
-      throw;
-    }
-  } catch (Exit& e) {
-    return e.status;
-  } catch (UsageError& e) {
-    LOG(INFO) << e.what();
-    LOG(INFO) << "Try '" << programName << " --help' for more information.";
-    return 1;
-  } catch (BaseError& e) {
-    LOG(ERROR) << error << (settings.showTrace ? e.prefix() : "") << e.msg();
-    if (!e.prefix().empty() && !settings.showTrace) {
-      LOG(INFO) << "(use '--show-trace' to show detailed location information)";
-    }
-    return static_cast<int>(e.status);
-  } catch (std::bad_alloc& e) {
-    LOG(ERROR) << error << "failed to allocate: " << e.what();
-    return 1;
-  } catch (std::exception& e) {
-    LOG(ERROR) << error << e.what();
-    return 1;
-  }
-
-  return 0;
-}
-
-RunPager::RunPager() {
-  if (isatty(STDOUT_FILENO) == 0) {
-    return;
-  }
-  char* pager = getenv("NIX_PAGER");
-  if (pager == nullptr) {
-    pager = getenv("PAGER");
-  }
-  if (pager && (std::string(pager) == "" || std::string(pager) == "cat")) {
-    return;
-  }
-
-  Pipe toPager;
-  toPager.create();
-
-  pid = startProcess([&]() {
-    if (dup2(toPager.readSide.get(), STDIN_FILENO) == -1) {
-      throw SysError("dupping stdin");
-    }
-    if (getenv("LESS") == nullptr) {
-      setenv("LESS", "FRSXMK", 1);
-    }
-    restoreSignals();
-    if (pager != nullptr) {
-      execl("/bin/sh", "sh", "-c", pager, nullptr);
-    }
-    execlp("pager", "pager", nullptr);
-    execlp("less", "less", nullptr);
-    execlp("more", "more", nullptr);
-    throw SysError(format("executing '%1%'") % pager);
-  });
-
-  pid.setKillSignal(SIGINT);
-
-  if (dup2(toPager.writeSide.get(), STDOUT_FILENO) == -1) {
-    throw SysError("dupping stdout");
-  }
-}
-
-RunPager::~RunPager() {
-  try {
-    if (pid != Pid(-1)) {
-      std::cout.flush();
-      close(STDOUT_FILENO);
-      pid.wait();
-    }
-  } catch (...) {
-    ignoreException();
-  }
-}
-
-std::string showBytes(unsigned long long bytes) {
-  return (format("%.2f MiB") % (bytes / (1024.0 * 1024.0))).str();
-}
-
-PrintFreed::~PrintFreed() {
-  if (show) {
-    std::cout << format("%1% store paths deleted, %2% freed\n") %
-                     results.paths.size() % showBytes(results.bytesFreed);
-  }
-}
-
-Exit::~Exit() = default;
-
-}  // namespace nix
diff --git a/third_party/nix/src/libmain/shared.hh b/third_party/nix/src/libmain/shared.hh
deleted file mode 100644
index d1061d5e04e5..000000000000
--- a/third_party/nix/src/libmain/shared.hh
+++ /dev/null
@@ -1,134 +0,0 @@
-#pragma once
-
-#include <locale>
-
-#include <absl/strings/numbers.h>
-#include <signal.h>
-
-#include "libmain/common-args.hh"
-#include "libutil/args.hh"
-#include "libutil/util.hh"
-
-namespace nix {
-
-class Exit : public std::exception {
- public:
-  int status;
-  Exit() : status(0) {}
-  Exit(int status) : status(status) {}
-  virtual ~Exit();
-};
-
-int handleExceptions(const std::string& programName,
-                     const std::function<void()>& fun);
-
-void initNix();
-
-void parseCmdLine(
-    int argc, char** argv,
-    std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-        parseArg);
-
-void parseCmdLine(
-    const std::string& programName, const Strings& args,
-    std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-        parseArg);
-
-void printVersion(const std::string& programName);
-
-/* Ugh.  No better place to put this. */
-void printGCWarning();
-
-class Store;
-
-void printMissing(const ref<Store>& store, const PathSet& paths);
-
-void printMissing(const ref<Store>& store, const PathSet& willBuild,
-                  const PathSet& willSubstitute, const PathSet& unknown,
-                  unsigned long long downloadSize, unsigned long long narSize);
-
-std::string getArg(const std::string& opt, Strings::iterator& i,
-                   const Strings::iterator& end);
-
-template <class N>
-N getIntArg(const std::string& opt, Strings::iterator& i,
-            const Strings::iterator& end, bool allowUnit) {
-  ++i;
-  if (i == end) {
-    throw UsageError(format("'%1%' requires an argument") % opt);
-  }
-  std::string s = *i;
-  N multiplier = 1;
-  if (allowUnit && !s.empty()) {
-    char u = std::toupper(*s.rbegin());
-    if (std::isalpha(u)) {
-      if (u == 'K') {
-        multiplier = 1ULL << 10;
-      } else if (u == 'M') {
-        multiplier = 1ULL << 20;
-      } else if (u == 'G') {
-        multiplier = 1ULL << 30;
-      } else if (u == 'T') {
-        multiplier = 1ULL << 40;
-      } else {
-        throw UsageError(format("invalid unit specifier '%1%'") % u);
-      }
-
-      s.resize(s.size() - 1);
-    }
-  }
-  N n;
-  if (!absl::SimpleAtoi(s, &n)) {
-    throw UsageError(format("'%1%' requires an integer argument") % opt);
-  }
-  return n * multiplier;
-}
-
-struct LegacyArgs : public MixCommonArgs {
-  std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-      parseArg;
-
-  LegacyArgs(
-      const std::string& programName,
-      std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
-          parseArg);
-
-  bool processFlag(Strings::iterator& pos, Strings::iterator end) override;
-
-  bool processArgs(const Strings& args, bool finish) override;
-};
-
-/* Show the manual page for the specified program. */
-void showManPage(const std::string& name);
-
-/* The constructor of this class starts a pager if stdout is a
-   terminal and $PAGER is set. Stdout is redirected to the pager. */
-class RunPager {
- public:
-  RunPager();
-  ~RunPager();
-
- private:
-  Pid pid;
-};
-
-extern volatile ::sig_atomic_t blockInt;
-
-/* GC helpers. */
-
-std::string showBytes(unsigned long long bytes);
-
-struct GCResults;
-
-struct PrintFreed {
-  bool show;
-  const GCResults& results;
-  PrintFreed(bool show, const GCResults& results)
-      : show(show), results(results) {}
-  ~PrintFreed();
-};
-
-/* Install a SIGSEGV handler to detect stack overflows. */
-void detectStackOverflow();
-
-}  // namespace nix
diff --git a/third_party/nix/src/libmain/stack.cc b/third_party/nix/src/libmain/stack.cc
deleted file mode 100644
index 628b6313a89c..000000000000
--- a/third_party/nix/src/libmain/stack.cc
+++ /dev/null
@@ -1,75 +0,0 @@
-#include <csignal>
-#include <cstddef>
-#include <cstdlib>
-#include <cstring>
-
-#include <unistd.h>
-
-#include "libutil/types.hh"
-
-namespace nix {
-
-static void sigsegvHandler(int signo, siginfo_t* info, void* ctx) {
-  /* Detect stack overflows by comparing the faulting address with
-     the stack pointer.  Unfortunately, getting the stack pointer is
-     not portable. */
-  bool haveSP = true;
-  char* sp = nullptr;
-#if defined(__x86_64__) && defined(REG_RSP)
-  sp = (char*)(static_cast<ucontext_t*>(ctx))->uc_mcontext.gregs[REG_RSP];
-#elif defined(REG_ESP)
-  sp = (char*)((ucontext_t*)ctx)->uc_mcontext.gregs[REG_ESP];
-#else
-  haveSP = false;
-#endif
-
-  if (haveSP) {
-    ptrdiff_t diff = static_cast<char*>(info->si_addr) - sp;
-    if (diff < 0) {
-      diff = -diff;
-    }
-    if (diff < 4096) {
-      char msg[] = "error: stack overflow (possible infinite recursion)\n";
-      [[gnu::unused]] auto res = write(2, msg, strlen(msg));
-      _exit(1);  // maybe abort instead?
-    }
-  }
-
-  /* Restore default behaviour (i.e. segfault and dump core). */
-  struct sigaction act;
-  sigfillset(&act.sa_mask);
-  act.sa_handler = SIG_DFL;
-  act.sa_flags = 0;
-  if (sigaction(SIGSEGV, &act, nullptr) != 0) {
-    abort();
-  }
-}
-
-void detectStackOverflow() {
-#if defined(SA_SIGINFO) && defined(SA_ONSTACK)
-  /* Install a SIGSEGV handler to detect stack overflows.  This
-     requires an alternative stack, otherwise the signal cannot be
-     delivered when we're out of stack space. */
-  stack_t stack;
-  stack.ss_size = 4096 * 4 + MINSIGSTKSZ;
-  static auto stackBuf = std::make_unique<std::vector<char>>(stack.ss_size);
-  stack.ss_sp = stackBuf->data();
-  if (stack.ss_sp == nullptr) {
-    throw Error("cannot allocate alternative stack");
-  }
-  stack.ss_flags = 0;
-  if (sigaltstack(&stack, nullptr) == -1) {
-    throw SysError("cannot set alternative stack");
-  }
-
-  struct sigaction act;
-  sigfillset(&act.sa_mask);
-  act.sa_sigaction = sigsegvHandler;
-  act.sa_flags = SA_SIGINFO | SA_ONSTACK;
-  if (sigaction(SIGSEGV, &act, nullptr) != 0) {
-    throw SysError("resetting SIGSEGV");
-  }
-#endif
-}
-
-}  // namespace nix