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#include "util.hh"
#include "processes.hh"
#include "strings.hh"
#include "current-process.hh"
#include "sync.hh"
#include "finally.hh"
#include "serialise.hh"
#include "cgroup.hh"
#include "signals.hh"
#include "environment-variables.hh"
#include "file-system.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
#ifdef NDEBUG
#error "Lix may not be built with assertions disabled (i.e. with -DNDEBUG)."
#endif
namespace nix {
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;
}
//////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
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 (...) { }
}
//////////////////////////////////////////////////////////////////////
#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
}
}
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