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llvm-mirror/lib/Support/Unix/Path.inc
Zachary Turner 4bf4431514 [Support] Re-add the special OSX flags on mmap. 
The problem appears to be that these flags can only be used
when mapping a file for read-only, not for readwrite.  So
we do that here.

llvm-svn: 295880
2017-02-22 21:24:06 +00:00

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26 KiB
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//===- llvm/Support/Unix/Path.inc - Unix Path Implementation ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Unix specific implementation of the Path API.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only generic UNIX code that
//=== is guaranteed to work on *all* UNIX variants.
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include <limits.h>
#include <stdio.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#if HAVE_DIRENT_H
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# if HAVE_SYS_NDIR_H
# include <sys/ndir.h>
# endif
# if HAVE_SYS_DIR_H
# include <sys/dir.h>
# endif
# if HAVE_NDIR_H
# include <ndir.h>
# endif
#endif
#ifdef __APPLE__
#include <mach-o/dyld.h>
#include <sys/attr.h>
#endif
// Both stdio.h and cstdio are included via different paths and
// stdcxx's cstdio doesn't include stdio.h, so it doesn't #undef the macros
// either.
#undef ferror
#undef feof
// For GNU Hurd
#if defined(__GNU__) && !defined(PATH_MAX)
# define PATH_MAX 4096
#endif
#include <sys/types.h>
#if !defined(__APPLE__) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && \
!defined(__linux__)
#include <sys/statvfs.h>
#define STATVFS statvfs
#define FSTATVFS fstatvfs
#define STATVFS_F_FRSIZE(vfs) vfs.f_frsize
#else
#if defined(__OpenBSD__) || defined(__FreeBSD__)
#include <sys/param.h>
#include <sys/mount.h>
#elif defined(__linux__)
#if defined(HAVE_LINUX_MAGIC_H)
#include <linux/magic.h>
#else
#if defined(HAVE_LINUX_NFS_FS_H)
#include <linux/nfs_fs.h>
#endif
#if defined(HAVE_LINUX_SMB_H)
#include <linux/smb.h>
#endif
#endif
#include <sys/vfs.h>
#else
#include <sys/mount.h>
#endif
#define STATVFS statfs
#define FSTATVFS fstatfs
#define STATVFS_F_FRSIZE(vfs) static_cast<uint64_t>(vfs.f_bsize)
#endif
#if defined(__NetBSD__)
#define STATVFS_F_FLAG(vfs) (vfs).f_flag
#else
#define STATVFS_F_FLAG(vfs) (vfs).f_flags
#endif
using namespace llvm;
namespace llvm {
namespace sys {
namespace fs {
#if defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__) || \
defined(__linux__) || defined(__CYGWIN__) || defined(__DragonFly__) || \
defined(_AIX)
static int
test_dir(char ret[PATH_MAX], const char *dir, const char *bin)
{
struct stat sb;
char fullpath[PATH_MAX];
snprintf(fullpath, PATH_MAX, "%s/%s", dir, bin);
if (!realpath(fullpath, ret))
return 1;
if (stat(fullpath, &sb) != 0)
return 1;
return 0;
}
static char *
getprogpath(char ret[PATH_MAX], const char *bin)
{
char *pv, *s, *t;
/* First approach: absolute path. */
if (bin[0] == '/') {
if (test_dir(ret, "/", bin) == 0)
return ret;
return nullptr;
}
/* Second approach: relative path. */
if (strchr(bin, '/')) {
char cwd[PATH_MAX];
if (!getcwd(cwd, PATH_MAX))
return nullptr;
if (test_dir(ret, cwd, bin) == 0)
return ret;
return nullptr;
}
/* Third approach: $PATH */
if ((pv = getenv("PATH")) == nullptr)
return nullptr;
s = pv = strdup(pv);
if (!pv)
return nullptr;
while ((t = strsep(&s, ":")) != nullptr) {
if (test_dir(ret, t, bin) == 0) {
free(pv);
return ret;
}
}
free(pv);
return nullptr;
}
#endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
/// GetMainExecutable - Return the path to the main executable, given the
/// value of argv[0] from program startup.
std::string getMainExecutable(const char *argv0, void *MainAddr) {
#if defined(__APPLE__)
// On OS X the executable path is saved to the stack by dyld. Reading it
// from there is much faster than calling dladdr, especially for large
// binaries with symbols.
char exe_path[MAXPATHLEN];
uint32_t size = sizeof(exe_path);
if (_NSGetExecutablePath(exe_path, &size) == 0) {
char link_path[MAXPATHLEN];
if (realpath(exe_path, link_path))
return link_path;
}
#elif defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
defined(__OpenBSD__) || defined(__minix) || defined(__DragonFly__) || \
defined(__FreeBSD_kernel__) || defined(_AIX)
char exe_path[PATH_MAX];
if (getprogpath(exe_path, argv0) != NULL)
return exe_path;
#elif defined(__linux__) || defined(__CYGWIN__)
char exe_path[MAXPATHLEN];
StringRef aPath("/proc/self/exe");
if (sys::fs::exists(aPath)) {
// /proc is not always mounted under Linux (chroot for example).
ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
if (len >= 0)
return std::string(exe_path, len);
} else {
// Fall back to the classical detection.
if (getprogpath(exe_path, argv0))
return exe_path;
}
#elif defined(HAVE_DLFCN_H) && defined(HAVE_DLADDR)
// Use dladdr to get executable path if available.
Dl_info DLInfo;
int err = dladdr(MainAddr, &DLInfo);
if (err == 0)
return "";
// If the filename is a symlink, we need to resolve and return the location of
// the actual executable.
char link_path[MAXPATHLEN];
if (realpath(DLInfo.dli_fname, link_path))
return link_path;
#else
#error GetMainExecutable is not implemented on this host yet.
#endif
return "";
}
TimePoint<> file_status::getLastAccessedTime() const {
return toTimePoint(fs_st_atime);
}
TimePoint<> file_status::getLastModificationTime() const {
return toTimePoint(fs_st_mtime);
}
UniqueID file_status::getUniqueID() const {
return UniqueID(fs_st_dev, fs_st_ino);
}
ErrorOr<space_info> disk_space(const Twine &Path) {
struct STATVFS Vfs;
if (::STATVFS(Path.str().c_str(), &Vfs))
return std::error_code(errno, std::generic_category());
auto FrSize = STATVFS_F_FRSIZE(Vfs);
space_info SpaceInfo;
SpaceInfo.capacity = static_cast<uint64_t>(Vfs.f_blocks) * FrSize;
SpaceInfo.free = static_cast<uint64_t>(Vfs.f_bfree) * FrSize;
SpaceInfo.available = static_cast<uint64_t>(Vfs.f_bavail) * FrSize;
return SpaceInfo;
}
std::error_code current_path(SmallVectorImpl<char> &result) {
result.clear();
const char *pwd = ::getenv("PWD");
llvm::sys::fs::file_status PWDStatus, DotStatus;
if (pwd && llvm::sys::path::is_absolute(pwd) &&
!llvm::sys::fs::status(pwd, PWDStatus) &&
!llvm::sys::fs::status(".", DotStatus) &&
PWDStatus.getUniqueID() == DotStatus.getUniqueID()) {
result.append(pwd, pwd + strlen(pwd));
return std::error_code();
}
#ifdef MAXPATHLEN
result.reserve(MAXPATHLEN);
#else
// For GNU Hurd
result.reserve(1024);
#endif
while (true) {
if (::getcwd(result.data(), result.capacity()) == nullptr) {
// See if there was a real error.
if (errno != ENOMEM)
return std::error_code(errno, std::generic_category());
// Otherwise there just wasn't enough space.
result.reserve(result.capacity() * 2);
} else
break;
}
result.set_size(strlen(result.data()));
return std::error_code();
}
std::error_code set_current_path(const Twine &path) {
SmallString<128> path_storage;
StringRef p = path.toNullTerminatedStringRef(path_storage);
if (::chdir(p.begin()) == -1)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
std::error_code create_directory(const Twine &path, bool IgnoreExisting,
perms Perms) {
SmallString<128> path_storage;
StringRef p = path.toNullTerminatedStringRef(path_storage);
if (::mkdir(p.begin(), Perms) == -1) {
if (errno != EEXIST || !IgnoreExisting)
return std::error_code(errno, std::generic_category());
}
return std::error_code();
}
// Note that we are using symbolic link because hard links are not supported by
// all filesystems (SMB doesn't).
std::error_code create_link(const Twine &to, const Twine &from) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
if (::symlink(t.begin(), f.begin()) == -1)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
std::error_code create_hard_link(const Twine &to, const Twine &from) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
if (::link(t.begin(), f.begin()) == -1)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
SmallString<128> path_storage;
StringRef p = path.toNullTerminatedStringRef(path_storage);
struct stat buf;
if (lstat(p.begin(), &buf) != 0) {
if (errno != ENOENT || !IgnoreNonExisting)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
// Note: this check catches strange situations. In all cases, LLVM should
// only be involved in the creation and deletion of regular files. This
// check ensures that what we're trying to erase is a regular file. It
// effectively prevents LLVM from erasing things like /dev/null, any block
// special file, or other things that aren't "regular" files.
if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode) && !S_ISLNK(buf.st_mode))
return make_error_code(errc::operation_not_permitted);
if (::remove(p.begin()) == -1) {
if (errno != ENOENT || !IgnoreNonExisting)
return std::error_code(errno, std::generic_category());
}
return std::error_code();
}
static bool is_local_impl(struct STATVFS &Vfs) {
#if defined(__linux__)
#ifndef NFS_SUPER_MAGIC
#define NFS_SUPER_MAGIC 0x6969
#endif
#ifndef SMB_SUPER_MAGIC
#define SMB_SUPER_MAGIC 0x517B
#endif
#ifndef CIFS_MAGIC_NUMBER
#define CIFS_MAGIC_NUMBER 0xFF534D42
#endif
switch ((uint32_t)Vfs.f_type) {
case NFS_SUPER_MAGIC:
case SMB_SUPER_MAGIC:
case CIFS_MAGIC_NUMBER:
return false;
default:
return true;
}
#else
return !!(STATVFS_F_FLAG(Vfs) & MNT_LOCAL);
#endif
}
std::error_code is_local(const Twine &Path, bool &Result) {
struct STATVFS Vfs;
if (::STATVFS(Path.str().c_str(), &Vfs))
return std::error_code(errno, std::generic_category());
Result = is_local_impl(Vfs);
return std::error_code();
}
std::error_code is_local(int FD, bool &Result) {
struct STATVFS Vfs;
if (::FSTATVFS(FD, &Vfs))
return std::error_code(errno, std::generic_category());
Result = is_local_impl(Vfs);
return std::error_code();
}
std::error_code rename(const Twine &from, const Twine &to) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
if (::rename(f.begin(), t.begin()) == -1)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
std::error_code resize_file(int FD, uint64_t Size) {
#if defined(HAVE_POSIX_FALLOCATE)
// If we have posix_fallocate use it. Unlike ftruncate it always allocates
// space, so we get an error if the disk is full.
if (int Err = ::posix_fallocate(FD, 0, Size))
return std::error_code(Err, std::generic_category());
#else
// Use ftruncate as a fallback. It may or may not allocate space. At least on
// OS X with HFS+ it does.
if (::ftruncate(FD, Size) == -1)
return std::error_code(errno, std::generic_category());
#endif
return std::error_code();
}
static int convertAccessMode(AccessMode Mode) {
switch (Mode) {
case AccessMode::Exist:
return F_OK;
case AccessMode::Write:
return W_OK;
case AccessMode::Execute:
return R_OK | X_OK; // scripts also need R_OK.
}
llvm_unreachable("invalid enum");
}
std::error_code access(const Twine &Path, AccessMode Mode) {
SmallString<128> PathStorage;
StringRef P = Path.toNullTerminatedStringRef(PathStorage);
if (::access(P.begin(), convertAccessMode(Mode)) == -1)
return std::error_code(errno, std::generic_category());
if (Mode == AccessMode::Execute) {
// Don't say that directories are executable.
struct stat buf;
if (0 != stat(P.begin(), &buf))
return errc::permission_denied;
if (!S_ISREG(buf.st_mode))
return errc::permission_denied;
}
return std::error_code();
}
bool can_execute(const Twine &Path) {
return !access(Path, AccessMode::Execute);
}
bool equivalent(file_status A, file_status B) {
assert(status_known(A) && status_known(B));
return A.fs_st_dev == B.fs_st_dev &&
A.fs_st_ino == B.fs_st_ino;
}
std::error_code equivalent(const Twine &A, const Twine &B, bool &result) {
file_status fsA, fsB;
if (std::error_code ec = status(A, fsA))
return ec;
if (std::error_code ec = status(B, fsB))
return ec;
result = equivalent(fsA, fsB);
return std::error_code();
}
static std::error_code fillStatus(int StatRet, const struct stat &Status,
file_status &Result) {
if (StatRet != 0) {
std::error_code ec(errno, std::generic_category());
if (ec == errc::no_such_file_or_directory)
Result = file_status(file_type::file_not_found);
else
Result = file_status(file_type::status_error);
return ec;
}
file_type Type = file_type::type_unknown;
if (S_ISDIR(Status.st_mode))
Type = file_type::directory_file;
else if (S_ISREG(Status.st_mode))
Type = file_type::regular_file;
else if (S_ISBLK(Status.st_mode))
Type = file_type::block_file;
else if (S_ISCHR(Status.st_mode))
Type = file_type::character_file;
else if (S_ISFIFO(Status.st_mode))
Type = file_type::fifo_file;
else if (S_ISSOCK(Status.st_mode))
Type = file_type::socket_file;
perms Perms = static_cast<perms>(Status.st_mode);
Result =
file_status(Type, Perms, Status.st_dev, Status.st_ino, Status.st_atime,
Status.st_mtime, Status.st_uid, Status.st_gid,
Status.st_size);
return std::error_code();
}
std::error_code status(const Twine &Path, file_status &Result) {
SmallString<128> PathStorage;
StringRef P = Path.toNullTerminatedStringRef(PathStorage);
struct stat Status;
int StatRet = ::stat(P.begin(), &Status);
return fillStatus(StatRet, Status, Result);
}
std::error_code status(int FD, file_status &Result) {
struct stat Status;
int StatRet = ::fstat(FD, &Status);
return fillStatus(StatRet, Status, Result);
}
std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
#if defined(HAVE_FUTIMENS)
timespec Times[2];
Times[0] = Times[1] = sys::toTimeSpec(Time);
if (::futimens(FD, Times))
return std::error_code(errno, std::generic_category());
return std::error_code();
#elif defined(HAVE_FUTIMES)
timeval Times[2];
Times[0] = Times[1] = sys::toTimeVal(
std::chrono::time_point_cast<std::chrono::microseconds>(Time));
if (::futimes(FD, Times))
return std::error_code(errno, std::generic_category());
return std::error_code();
#else
#warning Missing futimes() and futimens()
return make_error_code(errc::function_not_supported);
#endif
}
std::error_code mapped_file_region::init(int FD, uint64_t Offset,
mapmode Mode) {
assert(Size != 0);
int flags = (Mode == readwrite) ? MAP_SHARED : MAP_PRIVATE;
int prot = (Mode == readonly) ? PROT_READ : (PROT_READ | PROT_WRITE);
#if defined(__APPLE__)
//----------------------------------------------------------------------
// Newer versions of MacOSX have a flag that will allow us to read from
// binaries whose code signature is invalid without crashing by using
// the MAP_RESILIENT_CODESIGN flag. Also if a file from removable media
// is mapped we can avoid crashing and return zeroes to any pages we try
// to read if the media becomes unavailable by using the
// MAP_RESILIENT_MEDIA flag. These flags are only usable when mapping
// with PROT_READ, so take care not to specify them otherwise.
//----------------------------------------------------------------------
if (Mode == readonly) {
#if defined(MAP_RESILIENT_CODESIGN)
flags |= MAP_RESILIENT_CODESIGN;
#endif
#if defined(MAP_RESILIENT_MEDIA)
flags |= MAP_RESILIENT_MEDIA;
#endif
}
#endif // #if defined (__APPLE__)
Mapping = ::mmap(nullptr, Size, prot, flags, FD, Offset);
if (Mapping == MAP_FAILED)
return std::error_code(errno, std::generic_category());
return std::error_code();
}
mapped_file_region::mapped_file_region(int fd, mapmode mode, uint64_t length,
uint64_t offset, std::error_code &ec)
: Size(length), Mapping() {
// Make sure that the requested size fits within SIZE_T.
if (length > std::numeric_limits<size_t>::max()) {
ec = make_error_code(errc::invalid_argument);
return;
}
ec = init(fd, offset, mode);
if (ec)
Mapping = nullptr;
}
mapped_file_region::~mapped_file_region() {
if (Mapping)
::munmap(Mapping, Size);
}
uint64_t mapped_file_region::size() const {
assert(Mapping && "Mapping failed but used anyway!");
return Size;
}
char *mapped_file_region::data() const {
assert(Mapping && "Mapping failed but used anyway!");
return reinterpret_cast<char*>(Mapping);
}
const char *mapped_file_region::const_data() const {
assert(Mapping && "Mapping failed but used anyway!");
return reinterpret_cast<const char*>(Mapping);
}
int mapped_file_region::alignment() {
return Process::getPageSize();
}
std::error_code detail::directory_iterator_construct(detail::DirIterState &it,
StringRef path){
SmallString<128> path_null(path);
DIR *directory = ::opendir(path_null.c_str());
if (!directory)
return std::error_code(errno, std::generic_category());
it.IterationHandle = reinterpret_cast<intptr_t>(directory);
// Add something for replace_filename to replace.
path::append(path_null, ".");
it.CurrentEntry = directory_entry(path_null.str());
return directory_iterator_increment(it);
}
std::error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
if (it.IterationHandle)
::closedir(reinterpret_cast<DIR *>(it.IterationHandle));
it.IterationHandle = 0;
it.CurrentEntry = directory_entry();
return std::error_code();
}
std::error_code detail::directory_iterator_increment(detail::DirIterState &it) {
errno = 0;
dirent *cur_dir = ::readdir(reinterpret_cast<DIR *>(it.IterationHandle));
if (cur_dir == nullptr && errno != 0) {
return std::error_code(errno, std::generic_category());
} else if (cur_dir != nullptr) {
StringRef name(cur_dir->d_name, NAMLEN(cur_dir));
if ((name.size() == 1 && name[0] == '.') ||
(name.size() == 2 && name[0] == '.' && name[1] == '.'))
return directory_iterator_increment(it);
it.CurrentEntry.replace_filename(name);
} else
return directory_iterator_destruct(it);
return std::error_code();
}
#if !defined(F_GETPATH)
static bool hasProcSelfFD() {
// If we have a /proc filesystem mounted, we can quickly establish the
// real name of the file with readlink
static const bool Result = (::access("/proc/self/fd", R_OK) == 0);
return Result;
}
#endif
std::error_code openFileForRead(const Twine &Name, int &ResultFD,
SmallVectorImpl<char> *RealPath) {
SmallString<128> Storage;
StringRef P = Name.toNullTerminatedStringRef(Storage);
int OpenFlags = O_RDONLY;
#ifdef O_CLOEXEC
OpenFlags |= O_CLOEXEC;
#endif
while ((ResultFD = open(P.begin(), OpenFlags)) < 0) {
if (errno != EINTR)
return std::error_code(errno, std::generic_category());
}
#ifndef O_CLOEXEC
int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
(void)r;
assert(r == 0 && "fcntl(F_SETFD, FD_CLOEXEC) failed");
#endif
// Attempt to get the real name of the file, if the user asked
if(!RealPath)
return std::error_code();
RealPath->clear();
#if defined(F_GETPATH)
// When F_GETPATH is availble, it is the quickest way to get
// the real path name.
char Buffer[MAXPATHLEN];
if (::fcntl(ResultFD, F_GETPATH, Buffer) != -1)
RealPath->append(Buffer, Buffer + strlen(Buffer));
#else
char Buffer[PATH_MAX];
if (hasProcSelfFD()) {
char ProcPath[64];
snprintf(ProcPath, sizeof(ProcPath), "/proc/self/fd/%d", ResultFD);
ssize_t CharCount = ::readlink(ProcPath, Buffer, sizeof(Buffer));
if (CharCount > 0)
RealPath->append(Buffer, Buffer + CharCount);
} else {
// Use ::realpath to get the real path name
if (::realpath(P.begin(), Buffer) != nullptr)
RealPath->append(Buffer, Buffer + strlen(Buffer));
}
#endif
return std::error_code();
}
std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
sys::fs::OpenFlags Flags, unsigned Mode) {
// Verify that we don't have both "append" and "excl".
assert((!(Flags & sys::fs::F_Excl) || !(Flags & sys::fs::F_Append)) &&
"Cannot specify both 'excl' and 'append' file creation flags!");
int OpenFlags = O_CREAT;
#ifdef O_CLOEXEC
OpenFlags |= O_CLOEXEC;
#endif
if (Flags & F_RW)
OpenFlags |= O_RDWR;
else
OpenFlags |= O_WRONLY;
if (Flags & F_Append)
OpenFlags |= O_APPEND;
else
OpenFlags |= O_TRUNC;
if (Flags & F_Excl)
OpenFlags |= O_EXCL;
SmallString<128> Storage;
StringRef P = Name.toNullTerminatedStringRef(Storage);
while ((ResultFD = open(P.begin(), OpenFlags, Mode)) < 0) {
if (errno != EINTR)
return std::error_code(errno, std::generic_category());
}
#ifndef O_CLOEXEC
int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
(void)r;
assert(r == 0 && "fcntl(F_SETFD, FD_CLOEXEC) failed");
#endif
return std::error_code();
}
std::error_code getPathFromOpenFD(int FD, SmallVectorImpl<char> &ResultPath) {
if (FD < 0)
return make_error_code(errc::bad_file_descriptor);
#if defined(F_GETPATH)
// When F_GETPATH is availble, it is the quickest way to get
// the path from a file descriptor.
ResultPath.reserve(MAXPATHLEN);
if (::fcntl(FD, F_GETPATH, ResultPath.begin()) == -1)
return std::error_code(errno, std::generic_category());
ResultPath.set_size(strlen(ResultPath.begin()));
#else
// If we have a /proc filesystem mounted, we can quickly establish the
// real name of the file with readlink. Otherwise, we don't know how to
// get the filename from a file descriptor. Give up.
if (!fs::hasProcSelfFD())
return make_error_code(errc::function_not_supported);
ResultPath.reserve(PATH_MAX);
char ProcPath[64];
snprintf(ProcPath, sizeof(ProcPath), "/proc/self/fd/%d", FD);
ssize_t CharCount = ::readlink(ProcPath, ResultPath.begin(), ResultPath.capacity());
if (CharCount < 0)
return std::error_code(errno, std::generic_category());
// Was the filename truncated?
if (static_cast<size_t>(CharCount) == ResultPath.capacity()) {
// Use lstat to get the size of the filename
struct stat sb;
if (::lstat(ProcPath, &sb) < 0)
return std::error_code(errno, std::generic_category());
ResultPath.reserve(sb.st_size + 1);
CharCount = ::readlink(ProcPath, ResultPath.begin(), ResultPath.capacity());
if (CharCount < 0)
return std::error_code(errno, std::generic_category());
// Test for race condition: did the link size change?
if (CharCount > sb.st_size)
return std::error_code(ENAMETOOLONG, std::generic_category());
}
ResultPath.set_size(static_cast<size_t>(CharCount));
#endif
return std::error_code();
}
} // end namespace fs
namespace path {
bool home_directory(SmallVectorImpl<char> &result) {
if (char *RequestedDir = getenv("HOME")) {
result.clear();
result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
return true;
}
return false;
}
static bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {
#if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
// On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
// macros defined in <unistd.h> on darwin >= 9
int ConfName = TempDir ? _CS_DARWIN_USER_TEMP_DIR
: _CS_DARWIN_USER_CACHE_DIR;
size_t ConfLen = confstr(ConfName, nullptr, 0);
if (ConfLen > 0) {
do {
Result.resize(ConfLen);
ConfLen = confstr(ConfName, Result.data(), Result.size());
} while (ConfLen > 0 && ConfLen != Result.size());
if (ConfLen > 0) {
assert(Result.back() == 0);
Result.pop_back();
return true;
}
Result.clear();
}
#endif
return false;
}
static bool getUserCacheDir(SmallVectorImpl<char> &Result) {
// First try using XDG_CACHE_HOME env variable,
// as specified in XDG Base Directory Specification at
// http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
if (const char *XdgCacheDir = std::getenv("XDG_CACHE_HOME")) {
Result.clear();
Result.append(XdgCacheDir, XdgCacheDir + strlen(XdgCacheDir));
return true;
}
// Try Darwin configuration query
if (getDarwinConfDir(false, Result))
return true;
// Use "$HOME/.cache" if $HOME is available
if (home_directory(Result)) {
append(Result, ".cache");
return true;
}
return false;
}
static const char *getEnvTempDir() {
// Check whether the temporary directory is specified by an environment
// variable.
const char *EnvironmentVariables[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};
for (const char *Env : EnvironmentVariables) {
if (const char *Dir = std::getenv(Env))
return Dir;
}
return nullptr;
}
static const char *getDefaultTempDir(bool ErasedOnReboot) {
#ifdef P_tmpdir
if ((bool)P_tmpdir)
return P_tmpdir;
#endif
if (ErasedOnReboot)
return "/tmp";
return "/var/tmp";
}
void system_temp_directory(bool ErasedOnReboot, SmallVectorImpl<char> &Result) {
Result.clear();
if (ErasedOnReboot) {
// There is no env variable for the cache directory.
if (const char *RequestedDir = getEnvTempDir()) {
Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
return;
}
}
if (getDarwinConfDir(ErasedOnReboot, Result))
return;
const char *RequestedDir = getDefaultTempDir(ErasedOnReboot);
Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
}
} // end namespace path
} // end namespace sys
} // end namespace llvm
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