Add 'third_party/nix/' from commit 'be66c7a6b24e3c3c6157fd37b86c7203d14acf10' r/724

git-subtree-dir: third_party/nix
git-subtree-mainline: cf8cd640c1adf74a3706efbcb0ea4625da106fb2
git-subtree-split: be66c7a6b24e3c3c6157fd37b86c7203d14acf10

7 files changed, 691 insertions, 0 deletions

diff --git a/third_party/nix/src/libmain/common-args.cc b/third_party/nix/src/libmain/common-args.cc
new file mode 100644
index 0000000000..9e1d7cee60
--- /dev/null
+++ b/third_party/nix/src/libmain/common-args.cc
@@ -0,0 +1,56 @@
+#include "common-args.hh"
+#include "globals.hh"
+
+namespace nix {
+
+MixCommonArgs::MixCommonArgs(const string & programName)
+    : programName(programName)
+{
+    mkFlag()
+        .longName("verbose")
+        .shortName('v')
+        .description("increase verbosity level")
+        .handler([]() { verbosity = (Verbosity) (verbosity + 1); });
+
+    mkFlag()
+        .longName("quiet")
+        .description("decrease verbosity level")
+        .handler([]() { verbosity = verbosity > lvlError ? (Verbosity) (verbosity - 1) : lvlError; });
+
+    mkFlag()
+        .longName("debug")
+        .description("enable debug output")
+        .handler([]() { verbosity = lvlDebug; });
+
+    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) {
+                warn(e.what());
+            }
+        });
+
+    mkFlag()
+        .longName("max-jobs")
+        .shortName('j')
+        .label("jobs")
+        .description("maximum number of parallel builds")
+        .handler([=](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);
+}
+
+}
diff --git a/third_party/nix/src/libmain/common-args.hh b/third_party/nix/src/libmain/common-args.hh
new file mode 100644
index 0000000000..a4de3dccf0
--- /dev/null
+++ b/third_party/nix/src/libmain/common-args.hh
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "args.hh"
+
+namespace nix {
+
+struct MixCommonArgs : virtual Args
+{
+    string programName;
+    MixCommonArgs(const 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);
+    }
+};
+
+}
diff --git a/third_party/nix/src/libmain/local.mk b/third_party/nix/src/libmain/local.mk
new file mode 100644
index 0000000000..0c80f5a0a0
--- /dev/null
+++ b/third_party/nix/src/libmain/local.mk
@@ -0,0 +1,15 @@
+libraries += libmain
+
+libmain_NAME = libnixmain
+
+libmain_DIR := $(d)
+
+libmain_SOURCES := $(wildcard $(d)/*.cc)
+
+libmain_LDFLAGS = $(OPENSSL_LIBS)
+
+libmain_LIBS = libstore libutil
+
+libmain_ALLOW_UNDEFINED = 1
+
+$(eval $(call install-file-in, $(d)/nix-main.pc, $(prefix)/lib/pkgconfig, 0644))
diff --git a/third_party/nix/src/libmain/nix-main.pc.in b/third_party/nix/src/libmain/nix-main.pc.in
new file mode 100644
index 0000000000..37b03dcd42
--- /dev/null
+++ b/third_party/nix/src/libmain/nix-main.pc.in
@@ -0,0 +1,9 @@
+prefix=@prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Nix
+Description: Nix Package Manager
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lnixmain
+Cflags: -I${includedir}/nix -std=c++17
diff --git a/third_party/nix/src/libmain/shared.cc b/third_party/nix/src/libmain/shared.cc
new file mode 100644
index 0000000000..d3dbfbc445
--- /dev/null
+++ b/third_party/nix/src/libmain/shared.cc
@@ -0,0 +1,381 @@
+#include "globals.hh"
+#include "shared.hh"
+#include "store-api.hh"
+#include "util.hh"
+
+#include <algorithm>
+#include <cctype>
+#include <exception>
+#include <iostream>
+#include <mutex>
+
+#include <cstdlib>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <openssl/crypto.h>
+
+
+namespace nix {
+
+
+static bool gcWarning = true;
+
+void printGCWarning()
+{
+    if (!gcWarning) return;
+    static bool haveWarned = false;
+    warnOnce(haveWarned,
+        "you did not specify '--add-root'; "
+        "the result might be removed by the garbage collector");
+}
+
+
+void printMissing(ref<Store> store, const PathSet & paths, Verbosity lvl)
+{
+    unsigned long long downloadSize, narSize;
+    PathSet willBuild, willSubstitute, unknown;
+    store->queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
+    printMissing(store, willBuild, willSubstitute, unknown, downloadSize, narSize, lvl);
+}
+
+
+void printMissing(ref<Store> store, const PathSet & willBuild,
+    const PathSet & willSubstitute, const PathSet & unknown,
+    unsigned long long downloadSize, unsigned long long narSize, Verbosity lvl)
+{
+    if (!willBuild.empty()) {
+        printMsg(lvl, "these derivations will be built:");
+        Paths sorted = store->topoSortPaths(willBuild);
+        reverse(sorted.begin(), sorted.end());
+        for (auto & i : sorted)
+            printMsg(lvl, fmt("  %s", i));
+    }
+
+    if (!willSubstitute.empty()) {
+        printMsg(lvl, fmt("these paths will be fetched (%.2f MiB download, %.2f MiB unpacked):",
+                downloadSize / (1024.0 * 1024.0),
+                narSize / (1024.0 * 1024.0)));
+        for (auto & i : willSubstitute)
+            printMsg(lvl, fmt("  %s", i));
+    }
+
+    if (!unknown.empty()) {
+        printMsg(lvl, fmt("don't know how to build these paths%s:",
+                (settings.readOnlyMode ? " (may be caused by read-only store access)" : "")));
+        for (auto & i : unknown)
+            printMsg(lvl, fmt("  %s", i));
+    }
+}
+
+
+string getArg(const 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, 0))
+        throw SysError("resetting SIGCHLD");
+
+    /* Install a dummy SIGUSR1 handler for use with pthread_kill(). */
+    act.sa_handler = sigHandler;
+    if (sigaction(SIGUSR1, &act, 0)) throw SysError("handling SIGUSR1");
+
+#if __APPLE__
+    /* HACK: on darwin, we need can’t use sigprocmask with SIGWINCH.
+     * Instead, add a dummy sigaction handler, and signalHandlerThread
+     * can handle the rest. */
+    struct sigaction sa;
+    sa.sa_handler = sigHandler;
+    if (sigaction(SIGWINCH, &sa, 0)) throw SysError("handling SIGWINCH");
+#endif
+
+    /* 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, 0);
+    srandom(tv.tv_usec);
+
+    /* On macOS, don't use the per-session TMPDIR (as set e.g. by
+       sshd). This breaks build users because they don't have access
+       to the TMPDIR, in particular in ‘nix-store --serve’. */
+#if __APPLE__
+    if (getuid() == 0 && hasPrefix(getEnv("TMPDIR"), "/var/folders/"))
+        unsetenv("TMPDIR");
+#endif
+}
+
+
+LegacyArgs::LegacyArgs(const std::string & programName,
+    std::function<bool(Strings::iterator & arg, const Strings::iterator & end)> parseArg)
+    : MixCommonArgs(programName), parseArg(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), parseArg);
+}
+
+
+void parseCmdLine(const string & programName, const Strings & args,
+    std::function<bool(Strings::iterator & arg, const Strings::iterator & end)> parseArg)
+{
+    LegacyArgs(programName, parseArg).parseCmdline(args);
+}
+
+
+void printVersion(const string & programName)
+{
+    std::cout << format("%1% (Nix) %2%") % programName % nixVersion << std::endl;
+    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 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 string & programName, std::function<void()> fun)
+{
+    ReceiveInterrupts receiveInterrupts; // FIXME: need better place for this
+
+    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) {
+        printError(
+            format(error + "%1%\nTry '%2% --help' for more information.")
+            % e.what() % programName);
+        return 1;
+    } catch (BaseError & e) {
+        printError(format(error + "%1%%2%") % (settings.showTrace ? e.prefix() : "") % e.msg());
+        if (e.prefix() != "" && !settings.showTrace)
+            printError("(use '--show-trace' to show detailed location information)");
+        return e.status;
+    } catch (std::bad_alloc & e) {
+        printError(error + "out of memory");
+        return 1;
+    } catch (std::exception & e) {
+        printError(error + e.what());
+        return 1;
+    }
+
+    return 0;
+}
+
+
+RunPager::RunPager()
+{
+    if (!isatty(STDOUT_FILENO)) return;
+    char * pager = getenv("NIX_PAGER");
+    if (!pager) pager = getenv("PAGER");
+    if (pager && ((string) pager == "" || (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"))
+            setenv("LESS", "FRSXMK", 1);
+        restoreSignals();
+        if (pager)
+            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 != -1) {
+            std::cout.flush();
+            close(STDOUT_FILENO);
+            pid.wait();
+        }
+    } catch (...) {
+        ignoreException();
+    }
+}
+
+
+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() { }
+
+}
diff --git a/third_party/nix/src/libmain/shared.hh b/third_party/nix/src/libmain/shared.hh
new file mode 100644
index 0000000000..8e4861232d
--- /dev/null
+++ b/third_party/nix/src/libmain/shared.hh
@@ -0,0 +1,126 @@
+#pragma once
+
+#include "util.hh"
+#include "args.hh"
+#include "common-args.hh"
+
+#include <signal.h>
+
+#include <locale>
+
+
+namespace nix {
+
+class Exit : public std::exception
+{
+public:
+    int status;
+    Exit() : status(0) { }
+    Exit(int status) : status(status) { }
+    virtual ~Exit();
+};
+
+int handleExceptions(const string & programName, std::function<void()> fun);
+
+/* Don't forget to call initPlugins() after settings are initialized! */
+void initNix();
+
+void parseCmdLine(int argc, char * * argv,
+    std::function<bool(Strings::iterator & arg, const Strings::iterator & end)> parseArg);
+
+void parseCmdLine(const string & programName, const Strings & args,
+    std::function<bool(Strings::iterator & arg, const Strings::iterator & end)> parseArg);
+
+void printVersion(const string & programName);
+
+/* Ugh.  No better place to put this. */
+void printGCWarning();
+
+class Store;
+
+void printMissing(ref<Store> store, const PathSet & paths, Verbosity lvl = lvlInfo);
+
+void printMissing(ref<Store> store, const PathSet & willBuild,
+    const PathSet & willSubstitute, const PathSet & unknown,
+    unsigned long long downloadSize, unsigned long long narSize, Verbosity lvl = lvlInfo);
+
+string getArg(const string & opt,
+    Strings::iterator & i, const Strings::iterator & end);
+
+template<class N> N getIntArg(const string & opt,
+    Strings::iterator & i, const Strings::iterator & end, bool allowUnit)
+{
+    ++i;
+    if (i == end) throw UsageError(format("'%1%' requires an argument") % opt);
+    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 (!string2Int(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 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. */
+
+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();
+
+
+}
diff --git a/third_party/nix/src/libmain/stack.cc b/third_party/nix/src/libmain/stack.cc
new file mode 100644
index 0000000000..e6224de7d2
--- /dev/null
+++ b/third_party/nix/src/libmain/stack.cc
@@ -0,0 +1,71 @@
+#include "types.hh"
+
+#include <cstring>
+#include <cstddef>
+#include <cstdlib>
+
+#include <unistd.h>
+#include <signal.h>
+
+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 = 0;
+#if defined(__x86_64__) && defined(REG_RSP)
+    sp = (char *) ((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 = (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, 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) throw Error("cannot allocate alternative stack");
+    stack.ss_flags = 0;
+    if (sigaltstack(&stack, 0) == -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, 0))
+        throw SysError("resetting SIGSEGV");
+#endif
+}
+
+
+}