1//===- llvm/Support/Unix/Path.inc - Unix Path Implementation ----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the Unix specific implementation of the Path API.
11//
12//===----------------------------------------------------------------------===//
13
14//===----------------------------------------------------------------------===//
15//=== WARNING: Implementation here must contain only generic UNIX code that
16//===          is guaranteed to work on *all* UNIX variants.
17//===----------------------------------------------------------------------===//
18
19#include "Unix.h"
20#include <limits.h>
21#include <stdio.h>
22#if HAVE_SYS_STAT_H
23#include <sys/stat.h>
24#endif
25#if HAVE_FCNTL_H
26#include <fcntl.h>
27#endif
28#ifdef HAVE_UNISTD_H
29#include <unistd.h>
30#endif
31#ifdef HAVE_SYS_MMAN_H
32#include <sys/mman.h>
33#endif
34
35#include <dirent.h>
36#include <pwd.h>
37
38#ifdef __APPLE__
39#include <mach-o/dyld.h>
40#include <sys/attr.h>
41#endif
42
43// Both stdio.h and cstdio are included via different paths and
44// stdcxx's cstdio doesn't include stdio.h, so it doesn't #undef the macros
45// either.
46#undef ferror
47#undef feof
48
49// For GNU Hurd
50#if defined(__GNU__) && !defined(PATH_MAX)
51# define PATH_MAX 4096
52#endif
53
54#include <sys/types.h>
55#if !defined(__APPLE__) && !defined(__OpenBSD__) && !defined(__FreeBSD__) &&   \
56    !defined(__linux__)
57#include <sys/statvfs.h>
58#define STATVFS statvfs
59#define FSTATVFS fstatvfs
60#define STATVFS_F_FRSIZE(vfs) vfs.f_frsize
61#else
62#if defined(__OpenBSD__) || defined(__FreeBSD__)
63#include <sys/mount.h>
64#include <sys/param.h>
65#elif defined(__linux__)
66#if defined(HAVE_LINUX_MAGIC_H)
67#include <linux/magic.h>
68#else
69#if defined(HAVE_LINUX_NFS_FS_H)
70#include <linux/nfs_fs.h>
71#endif
72#if defined(HAVE_LINUX_SMB_H)
73#include <linux/smb.h>
74#endif
75#endif
76#include <sys/vfs.h>
77#else
78#include <sys/mount.h>
79#endif
80#define STATVFS statfs
81#define FSTATVFS fstatfs
82#define STATVFS_F_FRSIZE(vfs) static_cast<uint64_t>(vfs.f_bsize)
83#endif
84
85#if defined(__NetBSD__)
86#define STATVFS_F_FLAG(vfs) (vfs).f_flag
87#else
88#define STATVFS_F_FLAG(vfs) (vfs).f_flags
89#endif
90
91using namespace llvm;
92
93namespace llvm {
94namespace sys  {
95namespace fs {
96#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||     \
97    defined(__minix) || defined(__FreeBSD_kernel__) || defined(__linux__) ||   \
98    defined(__CYGWIN__) || defined(__DragonFly__) || defined(_AIX)
99static int
100test_dir(char ret[PATH_MAX], const char *dir, const char *bin)
101{
102  struct stat sb;
103  char fullpath[PATH_MAX];
104
105  snprintf(fullpath, PATH_MAX, "%s/%s", dir, bin);
106  if (!realpath(fullpath, ret))
107    return 1;
108  if (stat(fullpath, &sb) != 0)
109    return 1;
110
111  return 0;
112}
113
114static char *
115getprogpath(char ret[PATH_MAX], const char *bin)
116{
117  char *pv, *s, *t;
118
119  /* First approach: absolute path. */
120  if (bin[0] == '/') {
121    if (test_dir(ret, "/", bin) == 0)
122      return ret;
123    return nullptr;
124  }
125
126  /* Second approach: relative path. */
127  if (strchr(bin, '/')) {
128    char cwd[PATH_MAX];
129    if (!getcwd(cwd, PATH_MAX))
130      return nullptr;
131    if (test_dir(ret, cwd, bin) == 0)
132      return ret;
133    return nullptr;
134  }
135
136  /* Third approach: $PATH */
137  if ((pv = getenv("PATH")) == nullptr)
138    return nullptr;
139  s = pv = strdup(pv);
140  if (!pv)
141    return nullptr;
142  while ((t = strsep(&s, ":")) != nullptr) {
143    if (test_dir(ret, t, bin) == 0) {
144      free(pv);
145      return ret;
146    }
147  }
148  free(pv);
149  return nullptr;
150}
151#endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
152
153/// GetMainExecutable - Return the path to the main executable, given the
154/// value of argv[0] from program startup.
155std::string getMainExecutable(const char *argv0, void *MainAddr) {
156#if defined(__APPLE__)
157  // On OS X the executable path is saved to the stack by dyld. Reading it
158  // from there is much faster than calling dladdr, especially for large
159  // binaries with symbols.
160  char exe_path[MAXPATHLEN];
161  uint32_t size = sizeof(exe_path);
162  if (_NSGetExecutablePath(exe_path, &size) == 0) {
163    char link_path[MAXPATHLEN];
164    if (realpath(exe_path, link_path))
165      return link_path;
166  }
167#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||   \
168    defined(__minix) || defined(__DragonFly__) ||                              \
169    defined(__FreeBSD_kernel__) || defined(_AIX)
170  char exe_path[PATH_MAX];
171
172  if (getprogpath(exe_path, argv0) != NULL)
173    return exe_path;
174#elif defined(__linux__) || defined(__CYGWIN__)
175  char exe_path[MAXPATHLEN];
176  StringRef aPath("/proc/self/exe");
177  if (sys::fs::exists(aPath)) {
178      // /proc is not always mounted under Linux (chroot for example).
179      ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
180      if (len >= 0)
181          return std::string(exe_path, len);
182  } else {
183      // Fall back to the classical detection.
184      if (getprogpath(exe_path, argv0))
185        return exe_path;
186  }
187#elif defined(HAVE_DLFCN_H) && defined(HAVE_DLADDR)
188  // Use dladdr to get executable path if available.
189  Dl_info DLInfo;
190  int err = dladdr(MainAddr, &DLInfo);
191  if (err == 0)
192    return "";
193
194  // If the filename is a symlink, we need to resolve and return the location of
195  // the actual executable.
196  char link_path[MAXPATHLEN];
197  if (realpath(DLInfo.dli_fname, link_path))
198    return link_path;
199#else
200#error GetMainExecutable is not implemented on this host yet.
201#endif
202  return "";
203}
204
205TimePoint<> basic_file_status::getLastAccessedTime() const {
206  return toTimePoint(fs_st_atime);
207}
208
209TimePoint<> basic_file_status::getLastModificationTime() const {
210  return toTimePoint(fs_st_mtime);
211}
212
213UniqueID file_status::getUniqueID() const {
214  return UniqueID(fs_st_dev, fs_st_ino);
215}
216
217uint32_t file_status::getLinkCount() const {
218  return fs_st_nlinks;
219}
220
221ErrorOr<space_info> disk_space(const Twine &Path) {
222  struct STATVFS Vfs;
223  if (::STATVFS(Path.str().c_str(), &Vfs))
224    return std::error_code(errno, std::generic_category());
225  auto FrSize = STATVFS_F_FRSIZE(Vfs);
226  space_info SpaceInfo;
227  SpaceInfo.capacity = static_cast<uint64_t>(Vfs.f_blocks) * FrSize;
228  SpaceInfo.free = static_cast<uint64_t>(Vfs.f_bfree) * FrSize;
229  SpaceInfo.available = static_cast<uint64_t>(Vfs.f_bavail) * FrSize;
230  return SpaceInfo;
231}
232
233std::error_code current_path(SmallVectorImpl<char> &result) {
234  result.clear();
235
236  const char *pwd = ::getenv("PWD");
237  llvm::sys::fs::file_status PWDStatus, DotStatus;
238  if (pwd && llvm::sys::path::is_absolute(pwd) &&
239      !llvm::sys::fs::status(pwd, PWDStatus) &&
240      !llvm::sys::fs::status(".", DotStatus) &&
241      PWDStatus.getUniqueID() == DotStatus.getUniqueID()) {
242    result.append(pwd, pwd + strlen(pwd));
243    return std::error_code();
244  }
245
246#ifdef MAXPATHLEN
247  result.reserve(MAXPATHLEN);
248#else
249// For GNU Hurd
250  result.reserve(1024);
251#endif
252
253  while (true) {
254    if (::getcwd(result.data(), result.capacity()) == nullptr) {
255      // See if there was a real error.
256      if (errno != ENOMEM)
257        return std::error_code(errno, std::generic_category());
258      // Otherwise there just wasn't enough space.
259      result.reserve(result.capacity() * 2);
260    } else
261      break;
262  }
263
264  result.set_size(strlen(result.data()));
265  return std::error_code();
266}
267
268std::error_code set_current_path(const Twine &path) {
269  SmallString<128> path_storage;
270  StringRef p = path.toNullTerminatedStringRef(path_storage);
271
272  if (::chdir(p.begin()) == -1)
273    return std::error_code(errno, std::generic_category());
274
275  return std::error_code();
276}
277
278std::error_code create_directory(const Twine &path, bool IgnoreExisting,
279                                 perms Perms) {
280  SmallString<128> path_storage;
281  StringRef p = path.toNullTerminatedStringRef(path_storage);
282
283  if (::mkdir(p.begin(), Perms) == -1) {
284    if (errno != EEXIST || !IgnoreExisting)
285      return std::error_code(errno, std::generic_category());
286  }
287
288  return std::error_code();
289}
290
291// Note that we are using symbolic link because hard links are not supported by
292// all filesystems (SMB doesn't).
293std::error_code create_link(const Twine &to, const Twine &from) {
294  // Get arguments.
295  SmallString<128> from_storage;
296  SmallString<128> to_storage;
297  StringRef f = from.toNullTerminatedStringRef(from_storage);
298  StringRef t = to.toNullTerminatedStringRef(to_storage);
299
300  if (::symlink(t.begin(), f.begin()) == -1)
301    return std::error_code(errno, std::generic_category());
302
303  return std::error_code();
304}
305
306std::error_code create_hard_link(const Twine &to, const Twine &from) {
307  // Get arguments.
308  SmallString<128> from_storage;
309  SmallString<128> to_storage;
310  StringRef f = from.toNullTerminatedStringRef(from_storage);
311  StringRef t = to.toNullTerminatedStringRef(to_storage);
312
313  if (::link(t.begin(), f.begin()) == -1)
314    return std::error_code(errno, std::generic_category());
315
316  return std::error_code();
317}
318
319std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
320  SmallString<128> path_storage;
321  StringRef p = path.toNullTerminatedStringRef(path_storage);
322
323  struct stat buf;
324  if (lstat(p.begin(), &buf) != 0) {
325    if (errno != ENOENT || !IgnoreNonExisting)
326      return std::error_code(errno, std::generic_category());
327    return std::error_code();
328  }
329
330  // Note: this check catches strange situations. In all cases, LLVM should
331  // only be involved in the creation and deletion of regular files.  This
332  // check ensures that what we're trying to erase is a regular file. It
333  // effectively prevents LLVM from erasing things like /dev/null, any block
334  // special file, or other things that aren't "regular" files.
335  if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode) && !S_ISLNK(buf.st_mode))
336    return make_error_code(errc::operation_not_permitted);
337
338  if (::remove(p.begin()) == -1) {
339    if (errno != ENOENT || !IgnoreNonExisting)
340      return std::error_code(errno, std::generic_category());
341  }
342
343  return std::error_code();
344}
345
346static bool is_local_impl(struct STATVFS &Vfs) {
347#if defined(__linux__)
348#ifndef NFS_SUPER_MAGIC
349#define NFS_SUPER_MAGIC 0x6969
350#endif
351#ifndef SMB_SUPER_MAGIC
352#define SMB_SUPER_MAGIC 0x517B
353#endif
354#ifndef CIFS_MAGIC_NUMBER
355#define CIFS_MAGIC_NUMBER 0xFF534D42
356#endif
357  switch ((uint32_t)Vfs.f_type) {
358  case NFS_SUPER_MAGIC:
359  case SMB_SUPER_MAGIC:
360  case CIFS_MAGIC_NUMBER:
361    return false;
362  default:
363    return true;
364  }
365#elif defined(__CYGWIN__)
366  // Cygwin doesn't expose this information; would need to use Win32 API.
367  return false;
368#elif defined(__sun)
369  // statvfs::f_basetype contains a null-terminated FSType name of the mounted target
370  StringRef fstype(Vfs.f_basetype);
371  // NFS is the only non-local fstype??
372  return !fstype.equals("nfs");
373#else
374  return !!(STATVFS_F_FLAG(Vfs) & MNT_LOCAL);
375#endif
376}
377
378std::error_code is_local(const Twine &Path, bool &Result) {
379  struct STATVFS Vfs;
380  if (::STATVFS(Path.str().c_str(), &Vfs))
381    return std::error_code(errno, std::generic_category());
382
383  Result = is_local_impl(Vfs);
384  return std::error_code();
385}
386
387std::error_code is_local(int FD, bool &Result) {
388  struct STATVFS Vfs;
389  if (::FSTATVFS(FD, &Vfs))
390    return std::error_code(errno, std::generic_category());
391
392  Result = is_local_impl(Vfs);
393  return std::error_code();
394}
395
396std::error_code rename(const Twine &from, const Twine &to) {
397  // Get arguments.
398  SmallString<128> from_storage;
399  SmallString<128> to_storage;
400  StringRef f = from.toNullTerminatedStringRef(from_storage);
401  StringRef t = to.toNullTerminatedStringRef(to_storage);
402
403  if (::rename(f.begin(), t.begin()) == -1)
404    return std::error_code(errno, std::generic_category());
405
406  return std::error_code();
407}
408
409std::error_code resize_file(int FD, uint64_t Size) {
410#if defined(HAVE_POSIX_FALLOCATE)
411  // If we have posix_fallocate use it. Unlike ftruncate it always allocates
412  // space, so we get an error if the disk is full.
413  if (int Err = ::posix_fallocate(FD, 0, Size)) {
414    if (Err != EINVAL && Err != EOPNOTSUPP)
415      return std::error_code(Err, std::generic_category());
416  }
417#endif
418  // Use ftruncate as a fallback. It may or may not allocate space. At least on
419  // OS X with HFS+ it does.
420  if (::ftruncate(FD, Size) == -1)
421    return std::error_code(errno, std::generic_category());
422
423  return std::error_code();
424}
425
426static int convertAccessMode(AccessMode Mode) {
427  switch (Mode) {
428  case AccessMode::Exist:
429    return F_OK;
430  case AccessMode::Write:
431    return W_OK;
432  case AccessMode::Execute:
433    return R_OK | X_OK; // scripts also need R_OK.
434  }
435  llvm_unreachable("invalid enum");
436}
437
438std::error_code access(const Twine &Path, AccessMode Mode) {
439  SmallString<128> PathStorage;
440  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
441
442  if (::access(P.begin(), convertAccessMode(Mode)) == -1)
443    return std::error_code(errno, std::generic_category());
444
445  if (Mode == AccessMode::Execute) {
446    // Don't say that directories are executable.
447    struct stat buf;
448    if (0 != stat(P.begin(), &buf))
449      return errc::permission_denied;
450    if (!S_ISREG(buf.st_mode))
451      return errc::permission_denied;
452  }
453
454  return std::error_code();
455}
456
457bool can_execute(const Twine &Path) {
458  return !access(Path, AccessMode::Execute);
459}
460
461bool equivalent(file_status A, file_status B) {
462  assert(status_known(A) && status_known(B));
463  return A.fs_st_dev == B.fs_st_dev &&
464         A.fs_st_ino == B.fs_st_ino;
465}
466
467std::error_code equivalent(const Twine &A, const Twine &B, bool &result) {
468  file_status fsA, fsB;
469  if (std::error_code ec = status(A, fsA))
470    return ec;
471  if (std::error_code ec = status(B, fsB))
472    return ec;
473  result = equivalent(fsA, fsB);
474  return std::error_code();
475}
476
477static void expandTildeExpr(SmallVectorImpl<char> &Path) {
478  StringRef PathStr(Path.begin(), Path.size());
479  if (PathStr.empty() || !PathStr.startswith("~"))
480    return;
481
482  PathStr = PathStr.drop_front();
483  StringRef Expr =
484      PathStr.take_until([](char c) { return path::is_separator(c); });
485  StringRef Remainder = PathStr.substr(Expr.size() + 1);
486  SmallString<128> Storage;
487  if (Expr.empty()) {
488    // This is just ~/..., resolve it to the current user's home dir.
489    if (!path::home_directory(Storage)) {
490      // For some reason we couldn't get the home directory.  Just exit.
491      return;
492    }
493
494    // Overwrite the first character and insert the rest.
495    Path[0] = Storage[0];
496    Path.insert(Path.begin() + 1, Storage.begin() + 1, Storage.end());
497    return;
498  }
499
500  // This is a string of the form ~username/, look up this user's entry in the
501  // password database.
502  struct passwd *Entry = nullptr;
503  std::string User = Expr.str();
504  Entry = ::getpwnam(User.c_str());
505
506  if (!Entry) {
507    // Unable to look up the entry, just return back the original path.
508    return;
509  }
510
511  Storage = Remainder;
512  Path.clear();
513  Path.append(Entry->pw_dir, Entry->pw_dir + strlen(Entry->pw_dir));
514  llvm::sys::path::append(Path, Storage);
515}
516
517static std::error_code fillStatus(int StatRet, const struct stat &Status,
518                             file_status &Result) {
519  if (StatRet != 0) {
520    std::error_code ec(errno, std::generic_category());
521    if (ec == errc::no_such_file_or_directory)
522      Result = file_status(file_type::file_not_found);
523    else
524      Result = file_status(file_type::status_error);
525    return ec;
526  }
527
528  file_type Type = file_type::type_unknown;
529
530  if (S_ISDIR(Status.st_mode))
531    Type = file_type::directory_file;
532  else if (S_ISREG(Status.st_mode))
533    Type = file_type::regular_file;
534  else if (S_ISBLK(Status.st_mode))
535    Type = file_type::block_file;
536  else if (S_ISCHR(Status.st_mode))
537    Type = file_type::character_file;
538  else if (S_ISFIFO(Status.st_mode))
539    Type = file_type::fifo_file;
540  else if (S_ISSOCK(Status.st_mode))
541    Type = file_type::socket_file;
542  else if (S_ISLNK(Status.st_mode))
543    Type = file_type::symlink_file;
544
545  perms Perms = static_cast<perms>(Status.st_mode) & all_perms;
546  Result = file_status(Type, Perms, Status.st_dev, Status.st_nlink,
547                       Status.st_ino, Status.st_atime, Status.st_mtime,
548                       Status.st_uid, Status.st_gid, Status.st_size);
549
550  return std::error_code();
551}
552
553std::error_code status(const Twine &Path, file_status &Result, bool Follow) {
554  SmallString<128> PathStorage;
555  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
556
557  struct stat Status;
558  int StatRet = (Follow ? ::stat : ::lstat)(P.begin(), &Status);
559  return fillStatus(StatRet, Status, Result);
560}
561
562std::error_code status(int FD, file_status &Result) {
563  struct stat Status;
564  int StatRet = ::fstat(FD, &Status);
565  return fillStatus(StatRet, Status, Result);
566}
567
568std::error_code setPermissions(const Twine &Path, perms Permissions) {
569  SmallString<128> PathStorage;
570  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
571
572  if (::chmod(P.begin(), Permissions))
573    return std::error_code(errno, std::generic_category());
574  return std::error_code();
575}
576
577std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
578#if defined(HAVE_FUTIMENS)
579  timespec Times[2];
580  Times[0] = Times[1] = sys::toTimeSpec(Time);
581  if (::futimens(FD, Times))
582    return std::error_code(errno, std::generic_category());
583  return std::error_code();
584#elif defined(HAVE_FUTIMES)
585  timeval Times[2];
586  Times[0] = Times[1] = sys::toTimeVal(
587      std::chrono::time_point_cast<std::chrono::microseconds>(Time));
588  if (::futimes(FD, Times))
589    return std::error_code(errno, std::generic_category());
590  return std::error_code();
591#else
592#warning Missing futimes() and futimens()
593  return make_error_code(errc::function_not_supported);
594#endif
595}
596
597std::error_code mapped_file_region::init(int FD, uint64_t Offset,
598                                         mapmode Mode) {
599  assert(Size != 0);
600
601  int flags = (Mode == readwrite) ? MAP_SHARED : MAP_PRIVATE;
602  int prot = (Mode == readonly) ? PROT_READ : (PROT_READ | PROT_WRITE);
603#if defined(__APPLE__)
604  //----------------------------------------------------------------------
605  // Newer versions of MacOSX have a flag that will allow us to read from
606  // binaries whose code signature is invalid without crashing by using
607  // the MAP_RESILIENT_CODESIGN flag. Also if a file from removable media
608  // is mapped we can avoid crashing and return zeroes to any pages we try
609  // to read if the media becomes unavailable by using the
610  // MAP_RESILIENT_MEDIA flag.  These flags are only usable when mapping
611  // with PROT_READ, so take care not to specify them otherwise.
612  //----------------------------------------------------------------------
613  if (Mode == readonly) {
614#if defined(MAP_RESILIENT_CODESIGN)
615    flags |= MAP_RESILIENT_CODESIGN;
616#endif
617#if defined(MAP_RESILIENT_MEDIA)
618    flags |= MAP_RESILIENT_MEDIA;
619#endif
620  }
621#endif // #if defined (__APPLE__)
622
623  Mapping = ::mmap(nullptr, Size, prot, flags, FD, Offset);
624  if (Mapping == MAP_FAILED)
625    return std::error_code(errno, std::generic_category());
626  return std::error_code();
627}
628
629mapped_file_region::mapped_file_region(int fd, mapmode mode, size_t length,
630                                       uint64_t offset, std::error_code &ec)
631    : Size(length), Mapping(), FD(fd), Mode(mode) {
632  (void)FD;
633  (void)Mode;
634  ec = init(fd, offset, mode);
635  if (ec)
636    Mapping = nullptr;
637}
638
639mapped_file_region::~mapped_file_region() {
640  if (Mapping)
641    ::munmap(Mapping, Size);
642}
643
644size_t mapped_file_region::size() const {
645  assert(Mapping && "Mapping failed but used anyway!");
646  return Size;
647}
648
649char *mapped_file_region::data() const {
650  assert(Mapping && "Mapping failed but used anyway!");
651  return reinterpret_cast<char*>(Mapping);
652}
653
654const char *mapped_file_region::const_data() const {
655  assert(Mapping && "Mapping failed but used anyway!");
656  return reinterpret_cast<const char*>(Mapping);
657}
658
659int mapped_file_region::alignment() {
660  return Process::getPageSize();
661}
662
663std::error_code detail::directory_iterator_construct(detail::DirIterState &it,
664                                                     StringRef path,
665                                                     bool follow_symlinks) {
666  SmallString<128> path_null(path);
667  DIR *directory = ::opendir(path_null.c_str());
668  if (!directory)
669    return std::error_code(errno, std::generic_category());
670
671  it.IterationHandle = reinterpret_cast<intptr_t>(directory);
672  // Add something for replace_filename to replace.
673  path::append(path_null, ".");
674  it.CurrentEntry = directory_entry(path_null.str(), follow_symlinks);
675  return directory_iterator_increment(it);
676}
677
678std::error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
679  if (it.IterationHandle)
680    ::closedir(reinterpret_cast<DIR *>(it.IterationHandle));
681  it.IterationHandle = 0;
682  it.CurrentEntry = directory_entry();
683  return std::error_code();
684}
685
686std::error_code detail::directory_iterator_increment(detail::DirIterState &it) {
687  errno = 0;
688  dirent *cur_dir = ::readdir(reinterpret_cast<DIR *>(it.IterationHandle));
689  if (cur_dir == nullptr && errno != 0) {
690    return std::error_code(errno, std::generic_category());
691  } else if (cur_dir != nullptr) {
692    StringRef name(cur_dir->d_name);
693    if ((name.size() == 1 && name[0] == '.') ||
694        (name.size() == 2 && name[0] == '.' && name[1] == '.'))
695      return directory_iterator_increment(it);
696    it.CurrentEntry.replace_filename(name);
697  } else
698    return directory_iterator_destruct(it);
699
700  return std::error_code();
701}
702
703ErrorOr<basic_file_status> directory_entry::status() const {
704  file_status s;
705  if (auto EC = fs::status(Path, s, FollowSymlinks))
706    return EC;
707  return s;
708}
709
710#if !defined(F_GETPATH)
711static bool hasProcSelfFD() {
712  // If we have a /proc filesystem mounted, we can quickly establish the
713  // real name of the file with readlink
714  static const bool Result = (::access("/proc/self/fd", R_OK) == 0);
715  return Result;
716}
717#endif
718
719std::error_code openFileForRead(const Twine &Name, int &ResultFD,
720                                SmallVectorImpl<char> *RealPath) {
721  SmallString<128> Storage;
722  StringRef P = Name.toNullTerminatedStringRef(Storage);
723  int OpenFlags = O_RDONLY;
724#ifdef O_CLOEXEC
725  OpenFlags |= O_CLOEXEC;
726#endif
727  if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags)) < 0)
728    return std::error_code(errno, std::generic_category());
729#ifndef O_CLOEXEC
730  int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
731  (void)r;
732  assert(r == 0 && "fcntl(F_SETFD, FD_CLOEXEC) failed");
733#endif
734  // Attempt to get the real name of the file, if the user asked
735  if(!RealPath)
736    return std::error_code();
737  RealPath->clear();
738#if defined(F_GETPATH)
739  // When F_GETPATH is availble, it is the quickest way to get
740  // the real path name.
741  char Buffer[MAXPATHLEN];
742  if (::fcntl(ResultFD, F_GETPATH, Buffer) != -1)
743    RealPath->append(Buffer, Buffer + strlen(Buffer));
744#else
745  char Buffer[PATH_MAX];
746  if (hasProcSelfFD()) {
747    char ProcPath[64];
748    snprintf(ProcPath, sizeof(ProcPath), "/proc/self/fd/%d", ResultFD);
749    ssize_t CharCount = ::readlink(ProcPath, Buffer, sizeof(Buffer));
750    if (CharCount > 0)
751      RealPath->append(Buffer, Buffer + CharCount);
752  } else {
753    // Use ::realpath to get the real path name
754    if (::realpath(P.begin(), Buffer) != nullptr)
755      RealPath->append(Buffer, Buffer + strlen(Buffer));
756  }
757#endif
758  return std::error_code();
759}
760
761std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
762                            sys::fs::OpenFlags Flags, unsigned Mode) {
763  // Verify that we don't have both "append" and "excl".
764  assert((!(Flags & sys::fs::F_Excl) || !(Flags & sys::fs::F_Append)) &&
765         "Cannot specify both 'excl' and 'append' file creation flags!");
766
767  int OpenFlags = O_CREAT;
768
769#ifdef O_CLOEXEC
770  OpenFlags |= O_CLOEXEC;
771#endif
772
773  if (Flags & F_RW)
774    OpenFlags |= O_RDWR;
775  else
776    OpenFlags |= O_WRONLY;
777
778  if (Flags & F_Append)
779    OpenFlags |= O_APPEND;
780  else if (!(Flags & F_NoTrunc))
781    OpenFlags |= O_TRUNC;
782
783  if (Flags & F_Excl)
784    OpenFlags |= O_EXCL;
785
786  SmallString<128> Storage;
787  StringRef P = Name.toNullTerminatedStringRef(Storage);
788  if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags, Mode)) < 0)
789    return std::error_code(errno, std::generic_category());
790#ifndef O_CLOEXEC
791  int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
792  (void)r;
793  assert(r == 0 && "fcntl(F_SETFD, FD_CLOEXEC) failed");
794#endif
795  return std::error_code();
796}
797
798template <typename T>
799static std::error_code remove_directories_impl(const T &Entry,
800                                               bool IgnoreErrors) {
801  std::error_code EC;
802  directory_iterator Begin(Entry, EC, false);
803  directory_iterator End;
804  while (Begin != End) {
805    auto &Item = *Begin;
806    ErrorOr<basic_file_status> st = Item.status();
807    if (!st && !IgnoreErrors)
808      return st.getError();
809
810    if (is_directory(*st)) {
811      EC = remove_directories_impl(Item, IgnoreErrors);
812      if (EC && !IgnoreErrors)
813        return EC;
814    }
815
816    EC = fs::remove(Item.path(), true);
817    if (EC && !IgnoreErrors)
818      return EC;
819
820    Begin.increment(EC);
821    if (EC && !IgnoreErrors)
822      return EC;
823  }
824  return std::error_code();
825}
826
827std::error_code remove_directories(const Twine &path, bool IgnoreErrors) {
828  auto EC = remove_directories_impl(path, IgnoreErrors);
829  if (EC && !IgnoreErrors)
830    return EC;
831  EC = fs::remove(path, true);
832  if (EC && !IgnoreErrors)
833    return EC;
834  return std::error_code();
835}
836
837std::error_code real_path(const Twine &path, SmallVectorImpl<char> &dest,
838                          bool expand_tilde) {
839  dest.clear();
840  if (path.isTriviallyEmpty())
841    return std::error_code();
842
843  if (expand_tilde) {
844    SmallString<128> Storage;
845    path.toVector(Storage);
846    expandTildeExpr(Storage);
847    return real_path(Storage, dest, false);
848  }
849
850  SmallString<128> Storage;
851  StringRef P = path.toNullTerminatedStringRef(Storage);
852  char Buffer[PATH_MAX];
853  if (::realpath(P.begin(), Buffer) == nullptr)
854    return std::error_code(errno, std::generic_category());
855  dest.append(Buffer, Buffer + strlen(Buffer));
856  return std::error_code();
857}
858
859} // end namespace fs
860
861namespace path {
862
863bool home_directory(SmallVectorImpl<char> &result) {
864  char *RequestedDir = getenv("HOME");
865  if (!RequestedDir) {
866    struct passwd *pw = getpwuid(getuid());
867    if (pw && pw->pw_dir)
868      RequestedDir = pw->pw_dir;
869  }
870  if (!RequestedDir)
871    return false;
872
873  result.clear();
874  result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
875  return true;
876}
877
878static bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {
879  #if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
880  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
881  // macros defined in <unistd.h> on darwin >= 9
882  int ConfName = TempDir ? _CS_DARWIN_USER_TEMP_DIR
883                         : _CS_DARWIN_USER_CACHE_DIR;
884  size_t ConfLen = confstr(ConfName, nullptr, 0);
885  if (ConfLen > 0) {
886    do {
887      Result.resize(ConfLen);
888      ConfLen = confstr(ConfName, Result.data(), Result.size());
889    } while (ConfLen > 0 && ConfLen != Result.size());
890
891    if (ConfLen > 0) {
892      assert(Result.back() == 0);
893      Result.pop_back();
894      return true;
895    }
896
897    Result.clear();
898  }
899  #endif
900  return false;
901}
902
903static bool getUserCacheDir(SmallVectorImpl<char> &Result) {
904  // First try using XDG_CACHE_HOME env variable,
905  // as specified in XDG Base Directory Specification at
906  // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
907  if (const char *XdgCacheDir = std::getenv("XDG_CACHE_HOME")) {
908    Result.clear();
909    Result.append(XdgCacheDir, XdgCacheDir + strlen(XdgCacheDir));
910    return true;
911  }
912
913  // Try Darwin configuration query
914  if (getDarwinConfDir(false, Result))
915    return true;
916
917  // Use "$HOME/.cache" if $HOME is available
918  if (home_directory(Result)) {
919    append(Result, ".cache");
920    return true;
921  }
922
923  return false;
924}
925
926static const char *getEnvTempDir() {
927  // Check whether the temporary directory is specified by an environment
928  // variable.
929  const char *EnvironmentVariables[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};
930  for (const char *Env : EnvironmentVariables) {
931    if (const char *Dir = std::getenv(Env))
932      return Dir;
933  }
934
935  return nullptr;
936}
937
938static const char *getDefaultTempDir(bool ErasedOnReboot) {
939#ifdef P_tmpdir
940  if ((bool)P_tmpdir)
941    return P_tmpdir;
942#endif
943
944  if (ErasedOnReboot)
945    return "/tmp";
946  return "/var/tmp";
947}
948
949void system_temp_directory(bool ErasedOnReboot, SmallVectorImpl<char> &Result) {
950  Result.clear();
951
952  if (ErasedOnReboot) {
953    // There is no env variable for the cache directory.
954    if (const char *RequestedDir = getEnvTempDir()) {
955      Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
956      return;
957    }
958  }
959
960  if (getDarwinConfDir(ErasedOnReboot, Result))
961    return;
962
963  const char *RequestedDir = getDefaultTempDir(ErasedOnReboot);
964  Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
965}
966
967} // end namespace path
968
969} // end namespace sys
970} // end namespace llvm
971