Path.inc revision 77e31bca0321c6b470a844e3d5468fd998eef44e 
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 "llvm/Support/Process.h"
21#if HAVE_SYS_STAT_H
22#include <sys/stat.h>
23#endif
24#if HAVE_FCNTL_H
25#include <fcntl.h>
26#endif
27#ifdef HAVE_SYS_MMAN_H
28#include <sys/mman.h>
29#endif
30#if HAVE_DIRENT_H
31# include <dirent.h>
32# define NAMLEN(dirent) strlen((dirent)->d_name)
33#else
34# define dirent direct
35# define NAMLEN(dirent) (dirent)->d_namlen
36# if HAVE_SYS_NDIR_H
37#  include <sys/ndir.h>
38# endif
39# if HAVE_SYS_DIR_H
40#  include <sys/dir.h>
41# endif
42# if HAVE_NDIR_H
43#  include <ndir.h>
44# endif
45#endif
46#if HAVE_STDIO_H
47#include <stdio.h>
48#endif
49#if HAVE_LIMITS_H
50#include <limits.h>
51#endif
52
53#ifdef __APPLE__
54#include <mach-o/dyld.h>
55#endif
56
57// Both stdio.h and cstdio are included via different pathes and
58// stdcxx's cstdio doesn't include stdio.h, so it doesn't #undef the macros
59// either.
60#undef ferror
61#undef feof
62
63// For GNU Hurd
64#if defined(__GNU__) && !defined(PATH_MAX)
65# define PATH_MAX 4096
66#endif
67
68using namespace llvm;
69
70namespace {
71  /// This class automatically closes the given file descriptor when it goes out
72  /// of scope. You can take back explicit ownership of the file descriptor by
73  /// calling take(). The destructor does not verify that close was successful.
74  /// Therefore, never allow this class to call close on a file descriptor that
75  /// has been read from or written to.
76  struct AutoFD {
77    int FileDescriptor;
78
79    AutoFD(int fd) : FileDescriptor(fd) {}
80    ~AutoFD() {
81      if (FileDescriptor >= 0)
82        ::close(FileDescriptor);
83    }
84
85    int take() {
86      int ret = FileDescriptor;
87      FileDescriptor = -1;
88      return ret;
89    }
90
91    operator int() const {return FileDescriptor;}
92  };
93
94  error_code TempDir(SmallVectorImpl<char> &result) {
95    // FIXME: Don't use TMPDIR if program is SUID or SGID enabled.
96    const char *dir = 0;
97    (dir = std::getenv("TMPDIR" )) ||
98    (dir = std::getenv("TMP"    )) ||
99    (dir = std::getenv("TEMP"   )) ||
100    (dir = std::getenv("TEMPDIR")) ||
101#ifdef P_tmpdir
102    (dir = P_tmpdir) ||
103#endif
104    (dir = "/tmp");
105
106    result.clear();
107    StringRef d(dir);
108    result.append(d.begin(), d.end());
109    return error_code::success();
110  }
111}
112
113static error_code createUniqueEntity(const Twine &Model, int &ResultFD,
114                                     SmallVectorImpl<char> &ResultPath,
115                                     bool MakeAbsolute, unsigned Mode,
116                                     FSEntity Type) {
117  SmallString<128> ModelStorage;
118  Model.toVector(ModelStorage);
119
120  if (MakeAbsolute) {
121    // Make model absolute by prepending a temp directory if it's not already.
122    bool absolute = sys::path::is_absolute(Twine(ModelStorage));
123    if (!absolute) {
124      SmallString<128> TDir;
125      if (error_code ec = TempDir(TDir)) return ec;
126      sys::path::append(TDir, Twine(ModelStorage));
127      ModelStorage.swap(TDir);
128    }
129  }
130
131  // From here on, DO NOT modify model. It may be needed if the randomly chosen
132  // path already exists.
133  ResultPath = ModelStorage;
134  // Null terminate.
135  ResultPath.push_back(0);
136  ResultPath.pop_back();
137
138retry_random_path:
139  // Replace '%' with random chars.
140  for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
141    if (ModelStorage[i] == '%')
142      ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
143  }
144
145  // Try to open + create the file.
146  switch (Type) {
147  case FS_File: {
148    int RandomFD = ::open(ResultPath.begin(), O_RDWR | O_CREAT | O_EXCL, Mode);
149    if (RandomFD == -1) {
150      int SavedErrno = errno;
151      // If the file existed, try again, otherwise, error.
152      if (SavedErrno == errc::file_exists)
153        goto retry_random_path;
154      return error_code(SavedErrno, system_category());
155    }
156
157    ResultFD = RandomFD;
158    return error_code::success();
159  }
160
161  case FS_Name: {
162    bool Exists;
163    error_code EC = sys::fs::exists(ResultPath.begin(), Exists);
164    if (EC)
165      return EC;
166    if (Exists)
167      goto retry_random_path;
168    return error_code::success();
169  }
170
171  case FS_Dir: {
172    bool Existed;
173    error_code EC = sys::fs::create_directory(ResultPath.begin(), Existed);
174    if (EC)
175      return EC;
176    if (Existed)
177      goto retry_random_path;
178    return error_code::success();
179  }
180  }
181  llvm_unreachable("Invalid Type");
182}
183
184namespace llvm {
185namespace sys  {
186namespace fs {
187#if defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
188    defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__) || \
189    defined(__linux__) || defined(__CYGWIN__)
190static int
191test_dir(char buf[PATH_MAX], char ret[PATH_MAX],
192    const char *dir, const char *bin)
193{
194  struct stat sb;
195
196  snprintf(buf, PATH_MAX, "%s/%s", dir, bin);
197  if (realpath(buf, ret) == NULL)
198    return (1);
199  if (stat(buf, &sb) != 0)
200    return (1);
201
202  return (0);
203}
204
205static char *
206getprogpath(char ret[PATH_MAX], const char *bin)
207{
208  char *pv, *s, *t, buf[PATH_MAX];
209
210  /* First approach: absolute path. */
211  if (bin[0] == '/') {
212    if (test_dir(buf, ret, "/", bin) == 0)
213      return (ret);
214    return (NULL);
215  }
216
217  /* Second approach: relative path. */
218  if (strchr(bin, '/') != NULL) {
219    if (getcwd(buf, PATH_MAX) == NULL)
220      return (NULL);
221    if (test_dir(buf, ret, buf, bin) == 0)
222      return (ret);
223    return (NULL);
224  }
225
226  /* Third approach: $PATH */
227  if ((pv = getenv("PATH")) == NULL)
228    return (NULL);
229  s = pv = strdup(pv);
230  if (pv == NULL)
231    return (NULL);
232  while ((t = strsep(&s, ":")) != NULL) {
233    if (test_dir(buf, ret, t, bin) == 0) {
234      free(pv);
235      return (ret);
236    }
237  }
238  free(pv);
239  return (NULL);
240}
241#endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
242
243/// GetMainExecutable - Return the path to the main executable, given the
244/// value of argv[0] from program startup.
245std::string getMainExecutable(const char *argv0, void *MainAddr) {
246#if defined(__APPLE__)
247  // On OS X the executable path is saved to the stack by dyld. Reading it
248  // from there is much faster than calling dladdr, especially for large
249  // binaries with symbols.
250  char exe_path[MAXPATHLEN];
251  uint32_t size = sizeof(exe_path);
252  if (_NSGetExecutablePath(exe_path, &size) == 0) {
253    char link_path[MAXPATHLEN];
254    if (realpath(exe_path, link_path))
255      return link_path;
256  }
257#elif defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
258      defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__)
259  char exe_path[PATH_MAX];
260
261  if (getprogpath(exe_path, argv0) != NULL)
262    return exe_path;
263#elif defined(__linux__) || defined(__CYGWIN__)
264  char exe_path[MAXPATHLEN];
265  StringRef aPath("/proc/self/exe");
266  if (sys::fs::exists(aPath)) {
267      // /proc is not always mounted under Linux (chroot for example).
268      ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
269      if (len >= 0)
270          return StringRef(exe_path, len);
271  } else {
272      // Fall back to the classical detection.
273      if (getprogpath(exe_path, argv0) != NULL)
274          return exe_path;
275  }
276#elif defined(HAVE_DLFCN_H)
277  // Use dladdr to get executable path if available.
278  Dl_info DLInfo;
279  int err = dladdr(MainAddr, &DLInfo);
280  if (err == 0)
281    return "";
282
283  // If the filename is a symlink, we need to resolve and return the location of
284  // the actual executable.
285  char link_path[MAXPATHLEN];
286  if (realpath(DLInfo.dli_fname, link_path))
287    return link_path;
288#else
289#error GetMainExecutable is not implemented on this host yet.
290#endif
291  return "";
292}
293
294TimeValue file_status::getLastModificationTime() const {
295  TimeValue Ret;
296  Ret.fromEpochTime(fs_st_mtime);
297  return Ret;
298}
299
300error_code current_path(SmallVectorImpl<char> &result) {
301#ifdef MAXPATHLEN
302  result.reserve(MAXPATHLEN);
303#else
304// For GNU Hurd
305  result.reserve(1024);
306#endif
307
308  while (true) {
309    if (::getcwd(result.data(), result.capacity()) == 0) {
310      // See if there was a real error.
311      if (errno != errc::not_enough_memory)
312        return error_code(errno, system_category());
313      // Otherwise there just wasn't enough space.
314      result.reserve(result.capacity() * 2);
315    } else
316      break;
317  }
318
319  result.set_size(strlen(result.data()));
320  return error_code::success();
321}
322
323error_code copy_file(const Twine &from, const Twine &to, copy_option copt) {
324 // Get arguments.
325  SmallString<128> from_storage;
326  SmallString<128> to_storage;
327  StringRef f = from.toNullTerminatedStringRef(from_storage);
328  StringRef t = to.toNullTerminatedStringRef(to_storage);
329
330  const size_t buf_sz = 32768;
331  char buffer[buf_sz];
332  int from_file = -1, to_file = -1;
333
334  // Open from.
335  if ((from_file = ::open(f.begin(), O_RDONLY)) < 0)
336    return error_code(errno, system_category());
337  AutoFD from_fd(from_file);
338
339  // Stat from.
340  struct stat from_stat;
341  if (::stat(f.begin(), &from_stat) != 0)
342    return error_code(errno, system_category());
343
344  // Setup to flags.
345  int to_flags = O_CREAT | O_WRONLY;
346  if (copt == copy_option::fail_if_exists)
347    to_flags |= O_EXCL;
348
349  // Open to.
350  if ((to_file = ::open(t.begin(), to_flags, from_stat.st_mode)) < 0)
351    return error_code(errno, system_category());
352  AutoFD to_fd(to_file);
353
354  // Copy!
355  ssize_t sz, sz_read = 1, sz_write;
356  while (sz_read > 0 &&
357         (sz_read = ::read(from_fd, buffer, buf_sz)) > 0) {
358    // Allow for partial writes - see Advanced Unix Programming (2nd Ed.),
359    // Marc Rochkind, Addison-Wesley, 2004, page 94
360    sz_write = 0;
361    do {
362      if ((sz = ::write(to_fd, buffer + sz_write, sz_read - sz_write)) < 0) {
363        sz_read = sz;  // cause read loop termination.
364        break;         // error.
365      }
366      sz_write += sz;
367    } while (sz_write < sz_read);
368  }
369
370  // After all the file operations above the return value of close actually
371  // matters.
372  if (::close(from_fd.take()) < 0) sz_read = -1;
373  if (::close(to_fd.take()) < 0) sz_read = -1;
374
375  // Check for errors.
376  if (sz_read < 0)
377    return error_code(errno, system_category());
378
379  return error_code::success();
380}
381
382error_code create_directory(const Twine &path, bool &existed) {
383  SmallString<128> path_storage;
384  StringRef p = path.toNullTerminatedStringRef(path_storage);
385
386  if (::mkdir(p.begin(), S_IRWXU | S_IRWXG) == -1) {
387    if (errno != errc::file_exists)
388      return error_code(errno, system_category());
389    existed = true;
390  } else
391    existed = false;
392
393  return error_code::success();
394}
395
396error_code create_hard_link(const Twine &to, const Twine &from) {
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 (::link(t.begin(), f.begin()) == -1)
404    return error_code(errno, system_category());
405
406  return error_code::success();
407}
408
409error_code create_symlink(const Twine &to, const Twine &from) {
410  // Get arguments.
411  SmallString<128> from_storage;
412  SmallString<128> to_storage;
413  StringRef f = from.toNullTerminatedStringRef(from_storage);
414  StringRef t = to.toNullTerminatedStringRef(to_storage);
415
416  if (::symlink(t.begin(), f.begin()) == -1)
417    return error_code(errno, system_category());
418
419  return error_code::success();
420}
421
422error_code remove(const Twine &path, bool &existed) {
423  SmallString<128> path_storage;
424  StringRef p = path.toNullTerminatedStringRef(path_storage);
425
426  struct stat buf;
427  if (stat(p.begin(), &buf) != 0) {
428    if (errno != errc::no_such_file_or_directory)
429      return error_code(errno, system_category());
430    existed = false;
431    return error_code::success();
432  }
433
434  // Note: this check catches strange situations. In all cases, LLVM should
435  // only be involved in the creation and deletion of regular files.  This
436  // check ensures that what we're trying to erase is a regular file. It
437  // effectively prevents LLVM from erasing things like /dev/null, any block
438  // special file, or other things that aren't "regular" files.
439  if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode))
440    return make_error_code(errc::operation_not_permitted);
441
442  if (::remove(p.begin()) == -1) {
443    if (errno != errc::no_such_file_or_directory)
444      return error_code(errno, system_category());
445    existed = false;
446  } else
447    existed = true;
448
449  return error_code::success();
450}
451
452error_code rename(const Twine &from, const Twine &to) {
453  // Get arguments.
454  SmallString<128> from_storage;
455  SmallString<128> to_storage;
456  StringRef f = from.toNullTerminatedStringRef(from_storage);
457  StringRef t = to.toNullTerminatedStringRef(to_storage);
458
459  if (::rename(f.begin(), t.begin()) == -1) {
460    // If it's a cross device link, copy then delete, otherwise return the error
461    if (errno == EXDEV) {
462      if (error_code ec = copy_file(from, to, copy_option::overwrite_if_exists))
463        return ec;
464      bool Existed;
465      if (error_code ec = remove(from, Existed))
466        return ec;
467    } else
468      return error_code(errno, system_category());
469  }
470
471  return error_code::success();
472}
473
474error_code resize_file(const Twine &path, uint64_t size) {
475  SmallString<128> path_storage;
476  StringRef p = path.toNullTerminatedStringRef(path_storage);
477
478  if (::truncate(p.begin(), size) == -1)
479    return error_code(errno, system_category());
480
481  return error_code::success();
482}
483
484error_code exists(const Twine &path, bool &result) {
485  SmallString<128> path_storage;
486  StringRef p = path.toNullTerminatedStringRef(path_storage);
487
488  if (::access(p.begin(), F_OK) == -1) {
489    if (errno != errc::no_such_file_or_directory)
490      return error_code(errno, system_category());
491    result = false;
492  } else
493    result = true;
494
495  return error_code::success();
496}
497
498bool can_write(const Twine &Path) {
499  SmallString<128> PathStorage;
500  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
501  return 0 == access(P.begin(), W_OK);
502}
503
504bool can_execute(const Twine &Path) {
505  SmallString<128> PathStorage;
506  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
507
508  if (0 != access(P.begin(), R_OK | X_OK))
509    return false;
510  struct stat buf;
511  if (0 != stat(P.begin(), &buf))
512    return false;
513  if (!S_ISREG(buf.st_mode))
514    return false;
515  return true;
516}
517
518bool equivalent(file_status A, file_status B) {
519  assert(status_known(A) && status_known(B));
520  return A.fs_st_dev == B.fs_st_dev &&
521         A.fs_st_ino == B.fs_st_ino;
522}
523
524error_code equivalent(const Twine &A, const Twine &B, bool &result) {
525  file_status fsA, fsB;
526  if (error_code ec = status(A, fsA)) return ec;
527  if (error_code ec = status(B, fsB)) return ec;
528  result = equivalent(fsA, fsB);
529  return error_code::success();
530}
531
532error_code getUniqueID(const Twine Path, uint64_t &Result) {
533  SmallString<128> Storage;
534  StringRef P = Path.toNullTerminatedStringRef(Storage);
535
536  struct stat Status;
537  if (::stat(P.begin(), &Status) != 0)
538    return error_code(errno, system_category());
539
540  Result = Status.st_ino;
541  return error_code::success();
542}
543
544error_code status(const Twine &path, file_status &result) {
545  SmallString<128> path_storage;
546  StringRef p = path.toNullTerminatedStringRef(path_storage);
547
548  struct stat status;
549  if (::stat(p.begin(), &status) != 0) {
550    error_code ec(errno, system_category());
551    if (ec == errc::no_such_file_or_directory)
552      result = file_status(file_type::file_not_found);
553    else
554      result = file_status(file_type::status_error);
555    return ec;
556  }
557
558  perms prms = static_cast<perms>(status.st_mode);
559  file_type Type = file_type::type_unknown;
560
561  if (S_ISDIR(status.st_mode))
562    Type = file_type::directory_file;
563  else if (S_ISREG(status.st_mode))
564    Type = file_type::regular_file;
565  else if (S_ISBLK(status.st_mode))
566    Type = file_type::block_file;
567  else if (S_ISCHR(status.st_mode))
568    Type = file_type::character_file;
569  else if (S_ISFIFO(status.st_mode))
570    Type = file_type::fifo_file;
571  else if (S_ISSOCK(status.st_mode))
572    Type = file_type::socket_file;
573
574  result =
575      file_status(Type, prms, status.st_dev, status.st_ino, status.st_mtime,
576                  status.st_uid, status.st_gid, status.st_size);
577
578  return error_code::success();
579}
580
581error_code setLastModificationAndAccessTime(int FD, TimeValue Time) {
582#if defined(HAVE_FUTIMENS)
583  timespec Times[2];
584  Times[0].tv_sec = Time.toPosixTime();
585  Times[0].tv_nsec = 0;
586  Times[1] = Times[0];
587  if (::futimens(FD, Times))
588#elif defined(HAVE_FUTIMES)
589  timeval Times[2];
590  Times[0].tv_sec = Time.toPosixTime();
591  Times[0].tv_usec = 0;
592  Times[1] = Times[0];
593  if (::futimes(FD, Times))
594#else
595#error Missing futimes() and futimens()
596#endif
597    return error_code(errno, system_category());
598  return error_code::success();
599}
600
601error_code mapped_file_region::init(int FD, bool CloseFD, uint64_t Offset) {
602  AutoFD ScopedFD(FD);
603  if (!CloseFD)
604    ScopedFD.take();
605
606  // Figure out how large the file is.
607  struct stat FileInfo;
608  if (fstat(FD, &FileInfo) == -1)
609    return error_code(errno, system_category());
610  uint64_t FileSize = FileInfo.st_size;
611
612  if (Size == 0)
613    Size = FileSize;
614  else if (FileSize < Size) {
615    // We need to grow the file.
616    if (ftruncate(FD, Size) == -1)
617      return error_code(errno, system_category());
618  }
619
620  int flags = (Mode == readwrite) ? MAP_SHARED : MAP_PRIVATE;
621  int prot = (Mode == readonly) ? PROT_READ : (PROT_READ | PROT_WRITE);
622#ifdef MAP_FILE
623  flags |= MAP_FILE;
624#endif
625  Mapping = ::mmap(0, Size, prot, flags, FD, Offset);
626  if (Mapping == MAP_FAILED)
627    return error_code(errno, system_category());
628  return error_code::success();
629}
630
631mapped_file_region::mapped_file_region(const Twine &path,
632                                       mapmode mode,
633                                       uint64_t length,
634                                       uint64_t offset,
635                                       error_code &ec)
636  : Mode(mode)
637  , Size(length)
638  , Mapping() {
639  // Make sure that the requested size fits within SIZE_T.
640  if (length > std::numeric_limits<size_t>::max()) {
641    ec = make_error_code(errc::invalid_argument);
642    return;
643  }
644
645  SmallString<128> path_storage;
646  StringRef name = path.toNullTerminatedStringRef(path_storage);
647  int oflags = (mode == readonly) ? O_RDONLY : O_RDWR;
648  int ofd = ::open(name.begin(), oflags);
649  if (ofd == -1) {
650    ec = error_code(errno, system_category());
651    return;
652  }
653
654  ec = init(ofd, true, offset);
655  if (ec)
656    Mapping = 0;
657}
658
659mapped_file_region::mapped_file_region(int fd,
660                                       bool closefd,
661                                       mapmode mode,
662                                       uint64_t length,
663                                       uint64_t offset,
664                                       error_code &ec)
665  : Mode(mode)
666  , Size(length)
667  , Mapping() {
668  // Make sure that the requested size fits within SIZE_T.
669  if (length > std::numeric_limits<size_t>::max()) {
670    ec = make_error_code(errc::invalid_argument);
671    return;
672  }
673
674  ec = init(fd, closefd, offset);
675  if (ec)
676    Mapping = 0;
677}
678
679mapped_file_region::~mapped_file_region() {
680  if (Mapping)
681    ::munmap(Mapping, Size);
682}
683
684#if LLVM_HAS_RVALUE_REFERENCES
685mapped_file_region::mapped_file_region(mapped_file_region &&other)
686  : Mode(other.Mode), Size(other.Size), Mapping(other.Mapping) {
687  other.Mapping = 0;
688}
689#endif
690
691mapped_file_region::mapmode mapped_file_region::flags() const {
692  assert(Mapping && "Mapping failed but used anyway!");
693  return Mode;
694}
695
696uint64_t mapped_file_region::size() const {
697  assert(Mapping && "Mapping failed but used anyway!");
698  return Size;
699}
700
701char *mapped_file_region::data() const {
702  assert(Mapping && "Mapping failed but used anyway!");
703  assert(Mode != readonly && "Cannot get non const data for readonly mapping!");
704  return reinterpret_cast<char*>(Mapping);
705}
706
707const char *mapped_file_region::const_data() const {
708  assert(Mapping && "Mapping failed but used anyway!");
709  return reinterpret_cast<const char*>(Mapping);
710}
711
712int mapped_file_region::alignment() {
713  return process::get_self()->page_size();
714}
715
716error_code detail::directory_iterator_construct(detail::DirIterState &it,
717                                                StringRef path){
718  SmallString<128> path_null(path);
719  DIR *directory = ::opendir(path_null.c_str());
720  if (directory == 0)
721    return error_code(errno, system_category());
722
723  it.IterationHandle = reinterpret_cast<intptr_t>(directory);
724  // Add something for replace_filename to replace.
725  path::append(path_null, ".");
726  it.CurrentEntry = directory_entry(path_null.str());
727  return directory_iterator_increment(it);
728}
729
730error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
731  if (it.IterationHandle)
732    ::closedir(reinterpret_cast<DIR *>(it.IterationHandle));
733  it.IterationHandle = 0;
734  it.CurrentEntry = directory_entry();
735  return error_code::success();
736}
737
738error_code detail::directory_iterator_increment(detail::DirIterState &it) {
739  errno = 0;
740  dirent *cur_dir = ::readdir(reinterpret_cast<DIR *>(it.IterationHandle));
741  if (cur_dir == 0 && errno != 0) {
742    return error_code(errno, system_category());
743  } else if (cur_dir != 0) {
744    StringRef name(cur_dir->d_name, NAMLEN(cur_dir));
745    if ((name.size() == 1 && name[0] == '.') ||
746        (name.size() == 2 && name[0] == '.' && name[1] == '.'))
747      return directory_iterator_increment(it);
748    it.CurrentEntry.replace_filename(name);
749  } else
750    return directory_iterator_destruct(it);
751
752  return error_code::success();
753}
754
755error_code get_magic(const Twine &path, uint32_t len,
756                     SmallVectorImpl<char> &result) {
757  SmallString<128> PathStorage;
758  StringRef Path = path.toNullTerminatedStringRef(PathStorage);
759  result.set_size(0);
760
761  // Open path.
762  std::FILE *file = std::fopen(Path.data(), "rb");
763  if (file == 0)
764    return error_code(errno, system_category());
765
766  // Reserve storage.
767  result.reserve(len);
768
769  // Read magic!
770  size_t size = std::fread(result.data(), 1, len, file);
771  if (std::ferror(file) != 0) {
772    std::fclose(file);
773    return error_code(errno, system_category());
774  } else if (size != len) {
775    if (std::feof(file) != 0) {
776      std::fclose(file);
777      result.set_size(size);
778      return make_error_code(errc::value_too_large);
779    }
780  }
781  std::fclose(file);
782  result.set_size(size);
783  return error_code::success();
784}
785
786error_code map_file_pages(const Twine &path, off_t file_offset, size_t size,
787                                            bool map_writable, void *&result) {
788  SmallString<128> path_storage;
789  StringRef name = path.toNullTerminatedStringRef(path_storage);
790  int oflags = map_writable ? O_RDWR : O_RDONLY;
791  int ofd = ::open(name.begin(), oflags);
792  if ( ofd == -1 )
793    return error_code(errno, system_category());
794  AutoFD fd(ofd);
795  int flags = map_writable ? MAP_SHARED : MAP_PRIVATE;
796  int prot = map_writable ? (PROT_READ|PROT_WRITE) : PROT_READ;
797#ifdef MAP_FILE
798  flags |= MAP_FILE;
799#endif
800  result = ::mmap(0, size, prot, flags, fd, file_offset);
801  if (result == MAP_FAILED) {
802    return error_code(errno, system_category());
803  }
804
805  return error_code::success();
806}
807
808error_code unmap_file_pages(void *base, size_t size) {
809  if ( ::munmap(base, size) == -1 )
810    return error_code(errno, system_category());
811
812  return error_code::success();
813}
814
815
816} // end namespace fs
817} // end namespace sys
818} // end namespace llvm
819