diff options
Diffstat (limited to 'src/libutil/util.cc')
-rw-r--r-- | src/libutil/util.cc | 1916 |
1 files changed, 0 insertions, 1916 deletions
diff --git a/src/libutil/util.cc b/src/libutil/util.cc deleted file mode 100644 index 2c0fcc897..000000000 --- a/src/libutil/util.cc +++ /dev/null @@ -1,1916 +0,0 @@ -#include "util.hh" -#include "sync.hh" -#include "finally.hh" -#include "serialise.hh" -#include "cgroup.hh" -#include "signals.hh" - -#include <array> -#include <cctype> -#include <cerrno> -#include <climits> -#include <cstdio> -#include <cstdlib> -#include <cstring> -#include <future> -#include <iostream> -#include <mutex> -#include <sstream> -#include <thread> - -#include <fcntl.h> -#include <grp.h> -#include <pwd.h> -#include <sys/ioctl.h> -#include <sys/types.h> -#include <sys/socket.h> -#include <sys/wait.h> -#include <sys/time.h> -#include <sys/un.h> -#include <unistd.h> - -#ifdef __APPLE__ -#include <sys/syscall.h> -#include <mach-o/dyld.h> -#endif - -#ifdef __linux__ -#include <sys/prctl.h> -#include <sys/resource.h> -#include <sys/mman.h> - -#include <cmath> -#endif - - -extern char * * environ __attribute__((weak)); - - -#ifdef NDEBUG -#error "Lix may not be built with assertions disabled (i.e. with -DNDEBUG)." -#endif - -namespace nix { - -std::optional<std::string> getEnv(const std::string & key) -{ - char * value = getenv(key.c_str()); - if (!value) return {}; - return std::string(value); -} - -std::optional<std::string> getEnvNonEmpty(const std::string & key) { - auto value = getEnv(key); - if (value == "") return {}; - return value; -} - -std::map<std::string, std::string> getEnv() -{ - std::map<std::string, std::string> env; - for (size_t i = 0; environ[i]; ++i) { - auto s = environ[i]; - auto eq = strchr(s, '='); - if (!eq) - // 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 (auto & newEnvVar : newEnv) - setenv(newEnvVar.first.c_str(), newEnvVar.second.c_str(), 1); -} - - -Path absPath(Path path, std::optional<PathView> dir, bool resolveSymlinks) -{ - if (path.empty() || path[0] != '/') { - if (!dir) { -#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))) -#endif - throw SysError("cannot get cwd"); - path = concatStrings(buf, "/", path); -#ifdef __GNU__ - free(buf); -#endif - } else - path = concatStrings(*dir, "/", path); - } - return canonPath(path, resolveSymlinks); -} - - -Path canonPath(PathView path, bool resolveSymlinks) -{ - assert(path != ""); - - std::string s; - s.reserve(256); - - if (path[0] != '/') - throw Error("not an absolute path: '%1%'", path); - - 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, maxFollow = 1024; - - while (1) { - - /* Skip slashes. */ - while (!path.empty() && path[0] == '/') path.remove_prefix(1); - if (path.empty()) break; - - /* Ignore `.'. */ - if (path == "." || path.substr(0, 2) == "./") - path.remove_prefix(1); - - /* If `..', delete the last component. */ - else if (path == ".." || path.substr(0, 3) == "../") - { - if (!s.empty()) s.erase(s.rfind('/')); - path.remove_prefix(2); - } - - /* Normal component; copy it. */ - else { - s += '/'; - if (const auto slash = path.find('/'); slash == std::string::npos) { - s += path; - path = {}; - } else { - s += path.substr(0, slash); - path = path.substr(slash); - } - - /* If s points to a symlink, resolve it and continue from there */ - if (resolveSymlinks && isLink(s)) { - if (++followCount >= maxFollow) - throw Error("infinite symlink recursion in path '%1%'", path); - temp = concatStrings(readLink(s), path); - path = temp; - if (!temp.empty() && temp[0] == '/') { - s.clear(); /* restart for symlinks pointing to absolute path */ - } else { - s = dirOf(s); - if (s == "/") { // we don’t want trailing slashes here, which dirOf only produces if s = / - s.clear(); - } - } - } - } - } - - return s.empty() ? "/" : std::move(s); -} - -void chmodPath(const Path & path, mode_t mode) -{ - if (chmod(path.c_str(), mode) == -1) - throw SysError("setting permissions on '%s'", path); -} - -Path dirOf(const PathView path) -{ - Path::size_type pos = path.rfind('/'); - if (pos == std::string::npos) - return "."; - return pos == 0 ? "/" : Path(path, 0, pos); -} - - -std::string_view baseNameOf(std::string_view path) -{ - if (path.empty()) - return ""; - - auto last = path.size() - 1; - if (path[last] == '/' && last > 0) - last -= 1; - - auto pos = path.rfind('/', last); - if (pos == std::string::npos) - pos = 0; - else - pos += 1; - - return path.substr(pos, last - pos + 1); -} - - -std::string expandTilde(std::string_view path) -{ - // TODO: expand ~user ? - auto tilde = path.substr(0, 2); - if (tilde == "~/" || tilde == "~") - return getHome() + std::string(path.substr(1)); - else - return std::string(path); -} - - -bool isInDir(std::string_view path, std::string_view dir) -{ - return path.substr(0, 1) == "/" - && path.substr(0, dir.size()) == dir - && path.size() >= dir.size() + 2 - && path[dir.size()] == '/'; -} - - -bool isDirOrInDir(std::string_view path, std::string_view dir) -{ - return path == dir || isInDir(path, dir); -} - - -struct stat stat(const Path & path) -{ - struct stat st; - if (stat(path.c_str(), &st)) - throw SysError("getting status of '%1%'", path); - return st; -} - - -struct stat lstat(const Path & path) -{ - struct stat st; - if (lstat(path.c_str(), &st)) - throw SysError("getting status of '%1%'", path); - return st; -} - -std::optional<struct stat> maybeLstat(const Path & path) -{ - std::optional<struct stat> st{std::in_place}; - if (lstat(path.c_str(), &*st)) - { - if (errno == ENOENT || errno == ENOTDIR) - st.reset(); - else - throw SysError("getting status of '%s'", path); - } - return st; -} - -bool pathExists(const Path & path) -{ - return maybeLstat(path).has_value(); -} - -bool pathAccessible(const Path & path) -{ - try { - return pathExists(path); - } catch (SysError & e) { - // swallow EPERM - if (e.errNo == EPERM) return false; - throw; - } -} - - -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); - else - 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("reading directory '%1%'", path); - - return entries; -} - -DirEntries readDirectory(const Path & path) -{ - AutoCloseDir dir(opendir(path.c_str())); - if (!dir) throw SysError("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"); - - return drainFD(fd, true, st.st_size); -} - - -std::string readFile(const Path & path) -{ - AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)}; - if (!fd) - throw SysError("opening file '%1%'", path); - return readFile(fd.get()); -} - - -void readFile(const Path & path, Sink & sink) -{ - AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)}; - if (!fd) - throw SysError("opening file '%s'", path); - drainFD(fd.get(), sink); -} - - -void writeFile(const Path & path, std::string_view s, mode_t mode, bool sync) -{ - AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)}; - if (!fd) - throw SysError("opening file '%1%'", path); - try { - writeFull(fd.get(), s); - } catch (Error & e) { - e.addTrace({}, "writing file '%1%'", path); - throw; - } - if (sync) - fd.fsync(); - // Explicitly close to make sure exceptions are propagated. - fd.close(); - if (sync) - syncParent(path); -} - - -void writeFile(const Path & path, Source & source, mode_t mode, bool sync) -{ - AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)}; - if (!fd) - throw SysError("opening file '%1%'", path); - - std::vector<char> buf(64 * 1024); - - try { - while (true) { - try { - auto n = source.read(buf.data(), buf.size()); - writeFull(fd.get(), {buf.data(), n}); - } catch (EndOfFile &) { break; } - } - } catch (Error & e) { - e.addTrace({}, "writing file '%1%'", path); - throw; - } - if (sync) - fd.fsync(); - // Explicitly close to make sure exceptions are propagated. - fd.close(); - if (sync) - syncParent(path); -} - -void syncParent(const Path & path) -{ - AutoCloseFD fd{open(dirOf(path).c_str(), O_RDONLY, 0)}; - if (!fd) - throw SysError("opening file '%1%'", path); - fd.fsync(); -} - -std::string readLine(int fd) -{ - std::string s; - while (1) { - 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, uint64_t & 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("getting status of '%1%'", path); - } - - if (!S_ISDIR(st.st_mode)) { - /* We are about to delete a file. Will it likely free space? */ - - switch (st.st_nlink) { - /* Yes: last link. */ - case 1: - bytesFreed += st.st_size; - break; - /* Maybe: yes, if 'auto-optimise-store' or manual optimisation - was performed. Instead of checking for real let's assume - it's an optimised file and space will be freed. - - In worst case we will double count on freed space for files - with exactly two hardlinks for unoptimised packages. - */ - case 2: - bytesFreed += st.st_size; - break; - /* No: 3+ links. */ - default: - break; - } - } - - 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("chmod '%1%'", path); - } - - int fd = openat(parentfd, path.c_str(), O_RDONLY); - if (fd == -1) - throw SysError("opening directory '%1%'", path); - AutoCloseDir dir(fdopendir(fd)); - if (!dir) - throw SysError("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("cannot unlink '%1%'", path); - } -} - -static void _deletePath(const Path & path, uint64_t & bytesFreed) -{ - Path dir = dirOf(path); - if (dir == "") - dir = "/"; - - AutoCloseFD dirfd{open(dir.c_str(), O_RDONLY)}; - if (!dirfd) { - if (errno == ENOENT) return; - throw SysError("opening directory '%1%'", path); - } - - _deletePath(dirfd.get(), path, bytesFreed); -} - - -void deletePath(const Path & path) -{ - uint64_t dummy; - deletePath(path, dummy); -} - - -void deletePath(const Path & path, uint64_t & bytesFreed) -{ - //Activity act(*logger, lvlDebug, "recursively deleting path '%1%'", path); - bytesFreed = 0; - _deletePath(path, bytesFreed); -} - - -std::string getUserName() -{ - auto pw = getpwuid(geteuid()); - std::string name = pw ? pw->pw_name : getEnv("USER").value_or(""); - if (name.empty()) - throw Error("cannot figure out user name"); - return name; -} - -Path getHomeOf(uid_t userId) -{ - std::vector<char> buf(16384); - struct passwd pwbuf; - struct passwd * pw; - if (getpwuid_r(userId, &pwbuf, buf.data(), buf.size(), &pw) != 0 - || !pw || !pw->pw_dir || !pw->pw_dir[0]) - throw Error("cannot determine user's home directory"); - return pw->pw_dir; -} - -Path getHome() -{ - static Path homeDir = []() - { - std::optional<std::string> unownedUserHomeDir = {}; - auto homeDir = getEnv("HOME"); - if (homeDir) { - // Only use $HOME if doesn't exist or is owned by the current user. - struct stat st; - int result = stat(homeDir->c_str(), &st); - if (result != 0) { - if (errno != ENOENT) { - warn("couldn't stat $HOME ('%s') for reason other than not existing ('%d'), falling back to the one defined in the 'passwd' file", *homeDir, errno); - homeDir.reset(); - } - } else if (st.st_uid != geteuid()) { - unownedUserHomeDir.swap(homeDir); - } - } - if (!homeDir) { - homeDir = getHomeOf(geteuid()); - if (unownedUserHomeDir.has_value() && unownedUserHomeDir != homeDir) { - warn("$HOME ('%s') is not owned by you, falling back to the one defined in the 'passwd' file ('%s')", *unownedUserHomeDir, *homeDir); - } - } - return *homeDir; - }(); - return homeDir; -} - - -Path getCacheDir() -{ - auto cacheDir = getEnv("XDG_CACHE_HOME"); - return cacheDir ? *cacheDir : getHome() + "/.cache"; -} - - -Path getConfigDir() -{ - auto configDir = getEnv("XDG_CONFIG_HOME"); - return configDir ? *configDir : getHome() + "/.config"; -} - -std::vector<Path> getConfigDirs() -{ - Path configHome = getConfigDir(); - auto configDirs = getEnv("XDG_CONFIG_DIRS").value_or("/etc/xdg"); - std::vector<Path> result = tokenizeString<std::vector<std::string>>(configDirs, ":"); - result.insert(result.begin(), configHome); - return result; -} - - -Path getDataDir() -{ - auto dataDir = getEnv("XDG_DATA_HOME"); - return dataDir ? *dataDir : getHome() + "/.local/share"; -} - -Path getStateDir() -{ - auto stateDir = getEnv("XDG_STATE_HOME"); - return stateDir ? *stateDir : getHome() + "/.local/state"; -} - -Path createNixStateDir() -{ - Path dir = getStateDir() + "/nix"; - createDirs(dir); - return dir; -} - - -std::optional<Path> getSelfExe() -{ - static auto cached = []() -> std::optional<Path> - { - #if __linux__ - return readLink("/proc/self/exe"); - #elif __APPLE__ - char buf[1024]; - uint32_t size = sizeof(buf); - if (_NSGetExecutablePath(buf, &size) == 0) - return buf; - else - return std::nullopt; - #else - return std::nullopt; - #endif - }(); - return cached; -} - - -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("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("statting symlink '%1%'", path); - - if (!S_ISDIR(st.st_mode)) throw Error("'%1%' is not a directory", path); - - return created; -} - - -void readFull(int fd, char * buf, size_t count) -{ - while (count) { - checkInterrupt(); - ssize_t res = read(fd, 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, std::string_view s, bool allowInterrupts) -{ - while (!s.empty()) { - if (allowInterrupts) checkInterrupt(); - ssize_t res = write(fd, s.data(), s.size()); - if (res == -1 && errno != EINTR) - throw SysError("writing to file"); - if (res > 0) - s.remove_prefix(res); - } -} - - -std::string drainFD(int fd, bool block, const size_t reserveSize) -{ - // the parser needs two extra bytes to append terminating characters, other users will - // not care very much about the extra memory. - StringSink sink(reserveSize + 2); - drainFD(fd, sink, block); - return std::move(sink.s); -} - - -void drainFD(int fd, Sink & sink, bool block) -{ - // silence GCC maybe-uninitialized warning in finally - int saved = 0; - - if (!block) { - saved = fcntl(fd, F_GETFL); - if (fcntl(fd, F_SETFL, saved | O_NONBLOCK) == -1) - throw SysError("making file descriptor non-blocking"); - } - - Finally finally([&]() { - if (!block) { - if (fcntl(fd, F_SETFL, saved) == -1) - throw SysError("making file descriptor blocking"); - } - }); - - std::array<unsigned char, 64 * 1024> buf; - while (1) { - 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({(char *) buf.data(), (size_t) rd}); - } -} - -////////////////////////////////////////////////////////////////////// - -unsigned int getMaxCPU() -{ - #if __linux__ - try { - auto cgroupFS = getCgroupFS(); - if (!cgroupFS) return 0; - - auto cgroups = getCgroups("/proc/self/cgroup"); - auto cgroup = cgroups[""]; - if (cgroup == "") return 0; - - auto cpuFile = *cgroupFS + "/" + cgroup + "/cpu.max"; - - auto cpuMax = readFile(cpuFile); - auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n"); - - if (cpuMaxParts.size() != 2) { - return 0; - } - - auto quota = cpuMaxParts[0]; - auto period = cpuMaxParts[1]; - if (quota != "max") - return std::ceil(std::stoi(quota) / std::stof(period)); - } catch (Error &) { ignoreException(lvlDebug); } - #endif - - return 0; -} - -////////////////////////////////////////////////////////////////////// - - -AutoDelete::AutoDelete() : del{false} {} - -AutoDelete::AutoDelete(const std::string & p, bool recursive) : path(p) -{ - del = true; - this->recursive = recursive; -} - -AutoDelete::~AutoDelete() -{ - try { - if (del) { - if (recursive) - deletePath(path); - else { - if (remove(path.c_str()) == -1) - throw SysError("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("closing file descriptor %1%", fd); - fd = -1; - } -} - -void AutoCloseFD::fsync() -{ - if (fd != -1) { - int result; -#if __APPLE__ - result = ::fcntl(fd, F_FULLFSYNC); -#else - result = ::fsync(fd); -#endif - if (result == -1) - throw SysError("fsync 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]}; -} - - -void Pipe::close() -{ - readSide.close(); - writeSide.close(); -} - - -////////////////////////////////////////////////////////////////////// - - -Pid::Pid() -{ -} - - -Pid::Pid(pid_t pid) - : pid(pid) -{ -} - - -Pid::~Pid() noexcept(false) -{ - 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); - - debug("killing process %1%", 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) { - /* On BSDs, killing a process group will return EPERM if all - processes in the group are zombies (or something like - that). So try to detect and ignore that situation. */ -#if __FreeBSD__ || __APPLE__ - if (errno != EPERM || ::kill(pid, 0) != 0) -#endif - logError(SysError("killing process %d", pid).info()); - } - - return wait(); -} - - -int Pid::wait() -{ - assert(pid != -1); - while (1) { - int status; - int res = waitpid(pid, &status, 0); - if (res == pid) { - pid = -1; - return status; - } - if (errno != EINTR) - throw SysError("cannot get exit status of PID %d", pid); - 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) -{ - debug("killing all processes running under uid '%1%'", 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. */ - - Pid pid = startProcess([&]() { - - if (setuid(uid) == -1) - throw SysError("setting uid"); - - while (true) { -#ifdef __APPLE__ - /* OSX's kill syscall takes a third parameter that, among - other things, determines if kill(-1, signo) affects the - calling process. In the OSX libc, it's set to true, - which means "follow POSIX", which we don't want here - */ - if (syscall(SYS_kill, -1, SIGKILL, false) == 0) break; -#else - if (kill(-1, SIGKILL) == 0) break; -#endif - if (errno == ESRCH || errno == EPERM) break; /* no more processes */ - if (errno != EINTR) - throw SysError("cannot kill processes for uid '%1%'", uid); - } - - _exit(0); - }); - - int status = pid.wait(); - if (status != 0) - throw Error("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'. */ -} - - -////////////////////////////////////////////////////////////////////// - - -static pid_t doFork(std::function<void()> fun) -{ - pid_t pid = fork(); - if (pid != 0) return pid; - fun(); - abort(); -} - - -#if __linux__ -static int childEntry(void * arg) -{ - auto main = (std::function<void()> *) arg; - (*main)(); - return 1; -} -#endif - - -pid_t startProcess(std::function<void()> fun, const ProcessOptions & options) -{ - std::function<void()> wrapper = [&]() { - logger = makeSimpleLogger(); - try { -#if __linux__ - if (options.dieWithParent && prctl(PR_SET_PDEATHSIG, SIGKILL) == -1) - throw SysError("setting death signal"); -#endif - fun(); - } catch (std::exception & e) { - try { - std::cerr << options.errorPrefix << e.what() << "\n"; - } catch (...) { } - } catch (...) { } - if (options.runExitHandlers) - exit(1); - else - _exit(1); - }; - - pid_t pid = -1; - - if (options.cloneFlags) { - #ifdef __linux__ - // Not supported, since then we don't know when to free the stack. - assert(!(options.cloneFlags & CLONE_VM)); - - size_t stackSize = 1 * 1024 * 1024; - auto stack = (char *) mmap(0, stackSize, - PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); - if (stack == MAP_FAILED) throw SysError("allocating stack"); - - Finally freeStack([&]() { munmap(stack, stackSize); }); - - pid = clone(childEntry, stack + stackSize, options.cloneFlags | SIGCHLD, &wrapper); - #else - throw Error("clone flags are only supported on Linux"); - #endif - } else - 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((char *) s.c_str()); - res.push_back(0); - return res; -} - -std::string runProgram(Path program, bool searchPath, const Strings & args, - const std::optional<std::string> & input, bool isInteractive) -{ - auto res = runProgram(RunOptions {.program = program, .searchPath = searchPath, .args = args, .input = input, .isInteractive = isInteractive}); - - if (!statusOk(res.first)) - throw ExecError(res.first, "program '%1%' %2%", program, statusToString(res.first)); - - return res.second; -} - -// Output = error code + "standard out" output stream -std::pair<int, std::string> runProgram(RunOptions && 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, in; - if (options.standardOut) out.create(); - if (source) in.create(); - - ProcessOptions processOptions; - - std::optional<Finally<std::function<void()>>> resumeLoggerDefer; - if (options.isInteractive) { - logger->pause(); - resumeLoggerDefer.emplace( - []() { - logger->resume(); - } - ); - } - - /* Fork. */ - Pid pid = startProcess([&]() { - if (options.environment) - replaceEnv(*options.environment); - if (options.standardOut && 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 && 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, 0) == -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); - - restoreProcessContext(); - - if (options.searchPath) - execvp(options.program.c_str(), stringsToCharPtrs(args_).data()); - // This allows you to refer to a program with a pathname relative - // to the PATH variable. - else - execv(options.program.c_str(), stringsToCharPtrs(args_).data()); - - throw SysError("executing '%1%'", options.program); - }, processOptions); - - out.writeSide.close(); - - std::thread writerThread; - - std::promise<void> promise; - - Finally doJoin([&]() { - if (writerThread.joinable()) - writerThread.join(); - }); - - - if (source) { - in.readSide.close(); - writerThread = std::thread([&]() { - try { - std::vector<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.close(); - }); - } - - if (options.standardOut) - 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) promise.get_future().get(); - - if (status) - throw ExecError(status, "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)) { - debug("closing leaked FD %d", 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)) - 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"); -} - - -////////////////////////////////////////////////////////////////////// - - -template<class C> C tokenizeString(std::string_view s, std::string_view separators) -{ - C result; - auto pos = s.find_first_not_of(separators, 0); - while (pos != std::string_view::npos) { - auto end = s.find_first_of(separators, pos + 1); - if (end == std::string_view::npos) end = s.size(); - result.insert(result.end(), std::string(s, pos, end - pos)); - pos = s.find_first_not_of(separators, end); - } - return result; -} - -template Strings tokenizeString(std::string_view s, std::string_view separators); -template StringSet tokenizeString(std::string_view s, std::string_view separators); -template std::vector<std::string> tokenizeString(std::string_view s, std::string_view separators); - - -std::string chomp(std::string_view s) -{ - size_t i = s.find_last_not_of(" \n\r\t"); - return i == std::string_view::npos ? "" : std::string(s, 0, i + 1); -} - - -std::string trim(std::string_view s, std::string_view whitespace) -{ - auto i = s.find_first_not_of(whitespace); - if (i == s.npos) return ""; - auto j = s.find_last_not_of(whitespace); - return std::string(s, i, j == s.npos ? j : j - i + 1); -} - - -std::string replaceStrings( - std::string res, - std::string_view from, - std::string_view to) -{ - if (from.empty()) return res; - size_t pos = 0; - while ((pos = res.find(from, pos)) != std::string::npos) { - res.replace(pos, from.size(), to); - pos += to.size(); - } - return res; -} - - -Rewriter::Rewriter(std::map<std::string, std::string> rewrites) - : rewrites(std::move(rewrites)) -{ - for (const auto & [k, v] : this->rewrites) { - assert(!k.empty()); - initials.push_back(k[0]); - } - std::ranges::sort(initials); - auto [firstDupe, end] = std::ranges::unique(initials); - initials.erase(firstDupe, end); -} - -std::string Rewriter::operator()(std::string s) -{ - size_t j = 0; - while ((j = s.find_first_of(initials, j)) != std::string::npos) { - size_t skip = 1; - for (auto & [from, to] : rewrites) { - if (s.compare(j, from.size(), from) == 0) { - s.replace(j, from.size(), to); - skip = to.size(); - break; - } - } - j += skip; - } - return s; -} - - -std::string statusToString(int status) -{ - if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { - if (WIFEXITED(status)) - return fmt("failed with exit code %1%", WEXITSTATUS(status)); - else if (WIFSIGNALED(status)) { - int sig = WTERMSIG(status); -#if HAVE_STRSIGNAL - const char * description = strsignal(sig); - return fmt("failed due to signal %1% (%2%)", sig, description); -#else - return fmt("failed due to signal %1%", sig); -#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_view s) -{ - std::string r; - r.reserve(s.size() + 2); - r += "'"; - for (auto & i : s) - if (i == '\'') r += "'\\''"; else r += i; - r += '\''; - return r; -} - - -void ignoreException(Verbosity lvl) -{ - /* Make sure no exceptions leave this function. - printError() also throws when remote is closed. */ - try { - try { - throw; - } catch (std::exception & e) { - printMsg(lvl, "error (ignored): %1%", e.what()); - } - } catch (...) { } -} - -bool shouldANSI() -{ - return isatty(STDERR_FILENO) - && getEnv("TERM").value_or("dumb") != "dumb" - && !(getEnv("NO_COLOR").has_value() || getEnv("NOCOLOR").has_value()); -} - -std::string filterANSIEscapes(std::string_view s, bool filterAll, unsigned int width) -{ - std::string t, e; - size_t w = 0; - auto i = s.begin(); - - while (w < (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 < (size_t) width && w % 8) { - t += ' '; w++; - } - } - - else if (*i == '\r' || *i == '\a') - // do nothing for now - i++; - - else { - w++; - // Copy one UTF-8 character. - if ((*i & 0xe0) == 0xc0) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++; - } else if ((*i & 0xf0) == 0xe0) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++; - } - } else if ((*i & 0xf8) == 0xf0) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) { - t += *i++; - if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++; - } - } - } else - t += *i++; - } - } - - return t; -} - - -constexpr char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; - -std::string base64Encode(std::string_view s) -{ - std::string res; - res.reserve((s.size() + 2) / 3 * 4); - int data = 0, nbits = 0; - - for (char c : s) { - data = data << 8 | (unsigned char) c; - nbits += 8; - while (nbits >= 6) { - nbits -= 6; - res.push_back(base64Chars[data >> nbits & 0x3f]); - } - } - - if (nbits) res.push_back(base64Chars[data << (6 - nbits) & 0x3f]); - while (res.size() % 4) res.push_back('='); - - return res; -} - - -std::string base64Decode(std::string_view s) -{ - constexpr char npos = -1; - constexpr std::array<char, 256> base64DecodeChars = [&]() { - std::array<char, 256> result{}; - for (auto& c : result) - c = npos; - for (int i = 0; i < 64; i++) - result[base64Chars[i]] = i; - return result; - }(); - - std::string res; - // Some sequences are missing the padding consisting of up to two '='. - // vvv - res.reserve((s.size() + 2) / 4 * 3); - unsigned int d = 0, bits = 0; - - for (char c : s) { - if (c == '=') break; - if (c == '\n') continue; - - char digit = base64DecodeChars[(unsigned char) c]; - if (digit == npos) - throw Error("invalid character in Base64 string: '%c'", c); - - bits += 6; - d = d << 6 | digit; - if (bits >= 8) { - res.push_back(d >> (bits - 8) & 0xff); - bits -= 8; - } - } - - return res; -} - - -std::string stripIndentation(std::string_view s) -{ - size_t minIndent = 10000; - size_t curIndent = 0; - bool atStartOfLine = true; - - for (auto & c : s) { - if (atStartOfLine && c == ' ') - curIndent++; - else if (c == '\n') { - if (atStartOfLine) - minIndent = std::max(minIndent, curIndent); - curIndent = 0; - atStartOfLine = true; - } else { - if (atStartOfLine) { - minIndent = std::min(minIndent, curIndent); - atStartOfLine = false; - } - } - } - - std::string res; - - size_t pos = 0; - while (pos < s.size()) { - auto eol = s.find('\n', pos); - if (eol == s.npos) eol = s.size(); - if (eol - pos > minIndent) - res.append(s.substr(pos + minIndent, eol - pos - minIndent)); - res.push_back('\n'); - pos = eol + 1; - } - - return res; -} - - -std::pair<std::string_view, std::string_view> getLine(std::string_view s) -{ - auto newline = s.find('\n'); - - if (newline == s.npos) { - return {s, ""}; - } else { - auto line = s.substr(0, newline); - if (!line.empty() && line[line.size() - 1] == '\r') - line = line.substr(0, line.size() - 1); - return {line, s.substr(newline + 1)}; - } -} - - -////////////////////////////////////////////////////////////////////// - -static Sync<std::pair<unsigned short, unsigned short>> windowSize{{0, 0}}; - - -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(); -} - - -rlim_t savedStackSize = 0; - -void setStackSize(rlim_t stackSize) -{ - struct rlimit limit; - if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) { - savedStackSize = limit.rlim_cur; - limit.rlim_cur = std::min(stackSize, limit.rlim_max); - if (setrlimit(RLIMIT_STACK, &limit) != 0) { - logger->log( - lvlError, - HintFmt( - "Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%", - savedStackSize, - stackSize, - limit.rlim_max, - std::strerror(errno) - ).str() - ); - } - } -} - -#if __linux__ -static AutoCloseFD fdSavedMountNamespace; -static AutoCloseFD fdSavedRoot; -#endif - -void saveMountNamespace() -{ -#if __linux__ - static std::once_flag done; - std::call_once(done, []() { - fdSavedMountNamespace = AutoCloseFD{open("/proc/self/ns/mnt", O_RDONLY)}; - if (!fdSavedMountNamespace) - throw SysError("saving parent mount namespace"); - - fdSavedRoot = AutoCloseFD{open("/proc/self/root", O_RDONLY)}; - }); -#endif -} - -void restoreMountNamespace() -{ -#if __linux__ - try { - auto savedCwd = absPath("."); - - if (fdSavedMountNamespace && setns(fdSavedMountNamespace.get(), CLONE_NEWNS) == -1) - throw SysError("restoring parent mount namespace"); - - if (fdSavedRoot) { - if (fchdir(fdSavedRoot.get())) - throw SysError("chdir into saved root"); - if (chroot(".")) - throw SysError("chroot into saved root"); - } - - if (chdir(savedCwd.c_str()) == -1) - throw SysError("restoring cwd"); - } catch (Error & e) { - debug(e.msg()); - } -#endif -} - -void unshareFilesystem() -{ -#ifdef __linux__ - if (unshare(CLONE_FS) != 0 && errno != EPERM) - throw SysError("unsharing filesystem state in download thread"); -#endif -} - -void restoreProcessContext(bool restoreMounts) -{ - restoreSignals(); - if (restoreMounts) { - restoreMountNamespace(); - } - - if (savedStackSize) { - struct rlimit limit; - if (getrlimit(RLIMIT_STACK, &limit) == 0) { - limit.rlim_cur = savedStackSize; - setrlimit(RLIMIT_STACK, &limit); - } - } -} - -AutoCloseFD createUnixDomainSocket() -{ - AutoCloseFD fdSocket{socket(PF_UNIX, SOCK_STREAM - #ifdef SOCK_CLOEXEC - | SOCK_CLOEXEC - #endif - , 0)}; - if (!fdSocket) - throw SysError("cannot create Unix domain socket"); - closeOnExec(fdSocket.get()); - return fdSocket; -} - - -AutoCloseFD createUnixDomainSocket(const Path & path, mode_t mode) -{ - auto fdSocket = nix::createUnixDomainSocket(); - - bind(fdSocket.get(), path); - - chmodPath(path.c_str(), mode); - - if (listen(fdSocket.get(), 100) == -1) - throw SysError("cannot listen on socket '%1%'", path); - - return fdSocket; -} - - -static void bindConnectProcHelper( - std::string_view operationName, auto && operation, - int fd, const std::string & path) -{ - struct sockaddr_un addr; - addr.sun_family = AF_UNIX; - - // Casting between types like these legacy C library interfaces - // require is forbidden in C++. To maintain backwards - // compatibility, the implementation of the bind/connect functions - // contains some hints to the compiler that allow for this - // special case. - auto * psaddr = reinterpret_cast<struct sockaddr *>(&addr); - - if (path.size() + 1 >= sizeof(addr.sun_path)) { - Pipe pipe; - pipe.create(); - Pid pid = startProcess([&] { - try { - pipe.readSide.close(); - Path dir = dirOf(path); - if (chdir(dir.c_str()) == -1) - throw SysError("chdir to '%s' failed", dir); - std::string base(baseNameOf(path)); - if (base.size() + 1 >= sizeof(addr.sun_path)) - throw Error("socket path '%s' is too long", base); - memcpy(addr.sun_path, base.c_str(), base.size() + 1); - if (operation(fd, psaddr, sizeof(addr)) == -1) - throw SysError("cannot %s to socket at '%s'", operationName, path); - writeFull(pipe.writeSide.get(), "0\n"); - } catch (SysError & e) { - writeFull(pipe.writeSide.get(), fmt("%d\n", e.errNo)); - } catch (...) { - writeFull(pipe.writeSide.get(), "-1\n"); - } - }); - pipe.writeSide.close(); - auto errNo = string2Int<int>(chomp(drainFD(pipe.readSide.get()))); - if (!errNo || *errNo == -1) - throw Error("cannot %s to socket at '%s'", operationName, path); - else if (*errNo > 0) { - errno = *errNo; - throw SysError("cannot %s to socket at '%s'", operationName, path); - } - } else { - memcpy(addr.sun_path, path.c_str(), path.size() + 1); - if (operation(fd, psaddr, sizeof(addr)) == -1) - throw SysError("cannot %s to socket at '%s'", operationName, path); - } -} - - -void bind(int fd, const std::string & path) -{ - unlink(path.c_str()); - - bindConnectProcHelper("bind", ::bind, fd, path); -} - - -void connect(int fd, const std::string & path) -{ - bindConnectProcHelper("connect", ::connect, fd, path); -} - - -std::string showBytes(uint64_t bytes) -{ - return fmt("%.2f MiB", bytes / (1024.0 * 1024.0)); -} - - -// FIXME: move to libstore/build -void commonChildInit() -{ - logger = makeSimpleLogger(); - - const static std::string pathNullDevice = "/dev/null"; - restoreProcessContext(false); - - /* Put the child in a separate session (and thus a separate - process group) so that it has no controlling terminal (meaning - that e.g. ssh cannot open /dev/tty) and it doesn't receive - terminal signals. */ - if (setsid() == -1) - throw SysError("creating a new session"); - - /* Dup stderr to stdout. */ - if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1) - throw SysError("cannot dup stderr into stdout"); - - /* Reroute stdin to /dev/null. */ - int fdDevNull = open(pathNullDevice.c_str(), O_RDWR); - if (fdDevNull == -1) - throw SysError("cannot open '%1%'", pathNullDevice); - if (dup2(fdDevNull, STDIN_FILENO) == -1) - throw SysError("cannot dup null device into stdin"); - close(fdDevNull); -} - -} |