Coverage Report

Created: 2022-07-16 07:03

/Users/buildslave/jenkins/workspace/coverage/llvm-project/libcxx/src/filesystem/posix_compat.h
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// POSIX-like portability helper functions.
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//
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// These generally behave like the proper posix functions, with these
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// exceptions:
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// On Windows, they take paths in wchar_t* form, instead of char* form.
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// The symlink() function is split into two frontends, symlink_file()
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// and symlink_dir().
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//
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// These are provided within an anonymous namespace within the detail
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// namespace - callers need to include this header and call them as
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// detail::function(), regardless of platform.
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//
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#ifndef POSIX_COMPAT_H
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#define POSIX_COMPAT_H
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#include <__assert>
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#include <filesystem>
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#include "filesystem_common.h"
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#if defined(_LIBCPP_WIN32API)
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# define WIN32_LEAN_AND_MEAN
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# define NOMINMAX
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# include <windows.h>
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# include <io.h>
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# include <winioctl.h>
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#else
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# include <unistd.h>
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# include <sys/stat.h>
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# include <sys/statvfs.h>
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#endif
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#include <time.h>
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#if defined(_LIBCPP_WIN32API)
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// This struct isn't defined in the normal Windows SDK, but only in the
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// Windows Driver Kit.
47
struct LIBCPP_REPARSE_DATA_BUFFER {
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  unsigned long  ReparseTag;
49
  unsigned short ReparseDataLength;
50
  unsigned short Reserved;
51
  union {
52
    struct {
53
      unsigned short SubstituteNameOffset;
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      unsigned short SubstituteNameLength;
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      unsigned short PrintNameOffset;
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      unsigned short PrintNameLength;
57
      unsigned long  Flags;
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      wchar_t        PathBuffer[1];
59
    } SymbolicLinkReparseBuffer;
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    struct {
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      unsigned short SubstituteNameOffset;
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      unsigned short SubstituteNameLength;
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      unsigned short PrintNameOffset;
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      unsigned short PrintNameLength;
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      wchar_t        PathBuffer[1];
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    } MountPointReparseBuffer;
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    struct {
68
      unsigned char DataBuffer[1];
69
    } GenericReparseBuffer;
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  };
71
};
72
#endif
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_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
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namespace detail {
77
namespace {
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79
#if defined(_LIBCPP_WIN32API)
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// Various C runtime header sets provide more or less of these. As we
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// provide our own implementation, undef all potential defines from the
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// C runtime headers and provide a complete set of macros of our own.
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#undef _S_IFMT
86
#undef _S_IFDIR
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#undef _S_IFCHR
88
#undef _S_IFIFO
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#undef _S_IFREG
90
#undef _S_IFBLK
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#undef _S_IFLNK
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#undef _S_IFSOCK
93
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#define _S_IFMT   0xF000
95
#define _S_IFDIR  0x4000
96
#define _S_IFCHR  0x2000
97
#define _S_IFIFO  0x1000
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#define _S_IFREG  0x8000
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#define _S_IFBLK  0x6000
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#define _S_IFLNK  0xA000
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#define _S_IFSOCK 0xC000
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103
#undef S_ISDIR
104
#undef S_ISFIFO
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#undef S_ISCHR
106
#undef S_ISREG
107
#undef S_ISLNK
108
#undef S_ISBLK
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#undef S_ISSOCK
110
111
#define S_ISDIR(m)      (((m) & _S_IFMT) == _S_IFDIR)
112
#define S_ISCHR(m)      (((m) & _S_IFMT) == _S_IFCHR)
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#define S_ISFIFO(m)     (((m) & _S_IFMT) == _S_IFIFO)
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#define S_ISREG(m)      (((m) & _S_IFMT) == _S_IFREG)
115
#define S_ISBLK(m)      (((m) & _S_IFMT) == _S_IFBLK)
116
#define S_ISLNK(m)      (((m) & _S_IFMT) == _S_IFLNK)
117
#define S_ISSOCK(m)     (((m) & _S_IFMT) == _S_IFSOCK)
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#define O_NONBLOCK 0
120
121
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// There were 369 years and 89 leap days from the Windows epoch
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// (1601) to the Unix epoch (1970).
124
#define FILE_TIME_OFFSET_SECS (uint64_t(369 * 365 + 89) * (24 * 60 * 60))
125
126
TimeSpec filetime_to_timespec(LARGE_INTEGER li) {
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  TimeSpec ret;
128
  ret.tv_sec = li.QuadPart / 10000000 - FILE_TIME_OFFSET_SECS;
129
  ret.tv_nsec = (li.QuadPart % 10000000) * 100;
130
  return ret;
131
}
132
133
TimeSpec filetime_to_timespec(FILETIME ft) {
134
  LARGE_INTEGER li;
135
  li.LowPart = ft.dwLowDateTime;
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  li.HighPart = ft.dwHighDateTime;
137
  return filetime_to_timespec(li);
138
}
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140
FILETIME timespec_to_filetime(TimeSpec ts) {
141
  LARGE_INTEGER li;
142
  li.QuadPart =
143
      ts.tv_nsec / 100 + (ts.tv_sec + FILE_TIME_OFFSET_SECS) * 10000000;
144
  FILETIME ft;
145
  ft.dwLowDateTime = li.LowPart;
146
  ft.dwHighDateTime = li.HighPart;
147
  return ft;
148
}
149
150
int set_errno(int e = GetLastError()) {
151
  errno = static_cast<int>(__win_err_to_errc(e));
152
  return -1;
153
}
154
155
class WinHandle {
156
public:
157
  WinHandle(const wchar_t *p, DWORD access, DWORD flags) {
158
    h = CreateFileW(
159
        p, access, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
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        nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | flags, nullptr);
161
  }
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  ~WinHandle() {
163
    if (h != INVALID_HANDLE_VALUE)
164
      CloseHandle(h);
165
  }
166
  operator HANDLE() const { return h; }
167
  operator bool() const { return h != INVALID_HANDLE_VALUE; }
168
169
private:
170
  HANDLE h;
171
};
172
173
int stat_handle(HANDLE h, StatT *buf) {
174
  FILE_BASIC_INFO basic;
175
  if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
176
    return set_errno();
177
  memset(buf, 0, sizeof(*buf));
178
  buf->st_mtim = filetime_to_timespec(basic.LastWriteTime);
179
  buf->st_atim = filetime_to_timespec(basic.LastAccessTime);
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  buf->st_mode = 0555; // Read-only
181
  if (!(basic.FileAttributes & FILE_ATTRIBUTE_READONLY))
182
    buf->st_mode |= 0222; // Write
183
  if (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
184
    buf->st_mode |= _S_IFDIR;
185
  } else {
186
    buf->st_mode |= _S_IFREG;
187
  }
188
  if (basic.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
189
    FILE_ATTRIBUTE_TAG_INFO tag;
190
    if (!GetFileInformationByHandleEx(h, FileAttributeTagInfo, &tag,
191
                                      sizeof(tag)))
192
      return set_errno();
193
    if (tag.ReparseTag == IO_REPARSE_TAG_SYMLINK)
194
      buf->st_mode = (buf->st_mode & ~_S_IFMT) | _S_IFLNK;
195
  }
196
  FILE_STANDARD_INFO standard;
197
  if (!GetFileInformationByHandleEx(h, FileStandardInfo, &standard,
198
                                    sizeof(standard)))
199
    return set_errno();
200
  buf->st_nlink = standard.NumberOfLinks;
201
  buf->st_size = standard.EndOfFile.QuadPart;
202
  BY_HANDLE_FILE_INFORMATION info;
203
  if (!GetFileInformationByHandle(h, &info))
204
    return set_errno();
205
  buf->st_dev = info.dwVolumeSerialNumber;
206
  memcpy(&buf->st_ino.id[0], &info.nFileIndexHigh, 4);
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  memcpy(&buf->st_ino.id[4], &info.nFileIndexLow, 4);
208
  return 0;
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}
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int stat_file(const wchar_t *path, StatT *buf, DWORD flags) {
212
  WinHandle h(path, FILE_READ_ATTRIBUTES, flags);
213
  if (!h)
214
    return set_errno();
215
  int ret = stat_handle(h, buf);
216
  return ret;
217
}
218
219
int stat(const wchar_t *path, StatT *buf) { return stat_file(path, buf, 0); }
220
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int lstat(const wchar_t *path, StatT *buf) {
222
  return stat_file(path, buf, FILE_FLAG_OPEN_REPARSE_POINT);
223
}
224
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int fstat(int fd, StatT *buf) {
226
  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
227
  return stat_handle(h, buf);
228
}
229
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int mkdir(const wchar_t *path, int permissions) {
231
  (void)permissions;
232
  return _wmkdir(path);
233
}
234
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int symlink_file_dir(const wchar_t *oldname, const wchar_t *newname,
236
                     bool is_dir) {
237
  path dest(oldname);
238
  dest.make_preferred();
239
  oldname = dest.c_str();
240
  DWORD flags = is_dir ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
241
  if (CreateSymbolicLinkW(newname, oldname,
242
                          flags | SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
243
    return 0;
244
  int e = GetLastError();
245
  if (e != ERROR_INVALID_PARAMETER)
246
    return set_errno(e);
247
  if (CreateSymbolicLinkW(newname, oldname, flags))
248
    return 0;
249
  return set_errno();
250
}
251
252
int symlink_file(const wchar_t *oldname, const wchar_t *newname) {
253
  return symlink_file_dir(oldname, newname, false);
254
}
255
256
int symlink_dir(const wchar_t *oldname, const wchar_t *newname) {
257
  return symlink_file_dir(oldname, newname, true);
258
}
259
260
int link(const wchar_t *oldname, const wchar_t *newname) {
261
  if (CreateHardLinkW(newname, oldname, nullptr))
262
    return 0;
263
  return set_errno();
264
}
265
266
int remove(const wchar_t *path) {
267
  detail::WinHandle h(path, DELETE, FILE_FLAG_OPEN_REPARSE_POINT);
268
  if (!h)
269
    return set_errno();
270
  FILE_DISPOSITION_INFO info;
271
  info.DeleteFile = TRUE;
272
  if (!SetFileInformationByHandle(h, FileDispositionInfo, &info, sizeof(info)))
273
    return set_errno();
274
  return 0;
275
}
276
277
int truncate_handle(HANDLE h, off_t length) {
278
  LARGE_INTEGER size_param;
279
  size_param.QuadPart = length;
280
  if (!SetFilePointerEx(h, size_param, 0, FILE_BEGIN))
281
    return set_errno();
282
  if (!SetEndOfFile(h))
283
    return set_errno();
284
  return 0;
285
}
286
287
int ftruncate(int fd, off_t length) {
288
  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
289
  return truncate_handle(h, length);
290
}
291
292
int truncate(const wchar_t *path, off_t length) {
293
  detail::WinHandle h(path, GENERIC_WRITE, 0);
294
  if (!h)
295
    return set_errno();
296
  return truncate_handle(h, length);
297
}
298
299
int rename(const wchar_t *from, const wchar_t *to) {
300
  if (!(MoveFileExW(from, to,
301
                    MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING |
302
                        MOVEFILE_WRITE_THROUGH)))
303
    return set_errno();
304
  return 0;
305
}
306
307
template <class... Args> int open(const wchar_t *filename, Args... args) {
308
  return _wopen(filename, args...);
309
}
310
int close(int fd) { return _close(fd); }
311
int chdir(const wchar_t *path) { return _wchdir(path); }
312
313
struct StatVFS {
314
  uint64_t f_frsize;
315
  uint64_t f_blocks;
316
  uint64_t f_bfree;
317
  uint64_t f_bavail;
318
};
319
320
int statvfs(const wchar_t *p, StatVFS *buf) {
321
  path dir = p;
322
  while (true) {
323
    error_code local_ec;
324
    const file_status st = status(dir, local_ec);
325
    if (!exists(st) || is_directory(st))
326
      break;
327
    path parent = dir.parent_path();
328
    if (parent == dir) {
329
      errno = ENOENT;
330
      return -1;
331
    }
332
    dir = parent;
333
  }
334
  ULARGE_INTEGER free_bytes_available_to_caller, total_number_of_bytes,
335
      total_number_of_free_bytes;
336
  if (!GetDiskFreeSpaceExW(dir.c_str(), &free_bytes_available_to_caller,
337
                           &total_number_of_bytes, &total_number_of_free_bytes))
338
    return set_errno();
339
  buf->f_frsize = 1;
340
  buf->f_blocks = total_number_of_bytes.QuadPart;
341
  buf->f_bfree = total_number_of_free_bytes.QuadPart;
342
  buf->f_bavail = free_bytes_available_to_caller.QuadPart;
343
  return 0;
344
}
345
346
wchar_t *getcwd(wchar_t *buff, size_t size) { return _wgetcwd(buff, size); }
347
348
wchar_t *realpath(const wchar_t *path, wchar_t *resolved_name) {
349
  // Only expected to be used with us allocating the buffer.
350
  _LIBCPP_ASSERT(resolved_name == nullptr,
351
                 "Windows realpath() assumes a null resolved_name");
352
353
  WinHandle h(path, FILE_READ_ATTRIBUTES, 0);
354
  if (!h) {
355
    set_errno();
356
    return nullptr;
357
  }
358
  size_t buff_size = MAX_PATH + 10;
359
  std::unique_ptr<wchar_t, decltype(&::free)> buff(
360
      static_cast<wchar_t *>(malloc(buff_size * sizeof(wchar_t))), &::free);
361
  DWORD retval = GetFinalPathNameByHandleW(
362
      h, buff.get(), buff_size, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
363
  if (retval > buff_size) {
364
    buff_size = retval;
365
    buff.reset(static_cast<wchar_t *>(malloc(buff_size * sizeof(wchar_t))));
366
    retval = GetFinalPathNameByHandleW(h, buff.get(), buff_size,
367
                                       FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
368
  }
369
  if (!retval) {
370
    set_errno();
371
    return nullptr;
372
  }
373
  wchar_t *ptr = buff.get();
374
  if (!wcsncmp(ptr, L"\\\\?\\", 4)) {
375
    if (ptr[5] == ':') { // \\?\X: -> X:
376
      memmove(&ptr[0], &ptr[4], (wcslen(&ptr[4]) + 1) * sizeof(wchar_t));
377
    } else if (!wcsncmp(&ptr[4], L"UNC\\", 4)) { // \\?\UNC\server -> \\server
378
      wcscpy(&ptr[0], L"\\\\");
379
      memmove(&ptr[2], &ptr[8], (wcslen(&ptr[8]) + 1) * sizeof(wchar_t));
380
    }
381
  }
382
  return buff.release();
383
}
384
385
#define AT_FDCWD -1
386
#define AT_SYMLINK_NOFOLLOW 1
387
using ModeT = int;
388
389
int fchmod_handle(HANDLE h, int perms) {
390
  FILE_BASIC_INFO basic;
391
  if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
392
    return set_errno();
393
  DWORD orig_attributes = basic.FileAttributes;
394
  basic.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
395
  if ((perms & 0222) == 0)
396
    basic.FileAttributes |= FILE_ATTRIBUTE_READONLY;
397
  if (basic.FileAttributes != orig_attributes &&
398
      !SetFileInformationByHandle(h, FileBasicInfo, &basic, sizeof(basic)))
399
    return set_errno();
400
  return 0;
401
}
402
403
int fchmodat(int fd, const wchar_t *path, int perms, int flag) {
404
  DWORD attributes = GetFileAttributesW(path);
405
  if (attributes == INVALID_FILE_ATTRIBUTES)
406
    return set_errno();
407
  if (attributes & FILE_ATTRIBUTE_REPARSE_POINT &&
408
      !(flag & AT_SYMLINK_NOFOLLOW)) {
409
    // If the file is a symlink, and we are supposed to operate on the target
410
    // of the symlink, we need to open a handle to it, without the
411
    // FILE_FLAG_OPEN_REPARSE_POINT flag, to open the destination of the
412
    // symlink, and operate on it via the handle.
413
    detail::WinHandle h(path, FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES, 0);
414
    if (!h)
415
      return set_errno();
416
    return fchmod_handle(h, perms);
417
  } else {
418
    // For a non-symlink, or if operating on the symlink itself instead of
419
    // its target, we can use SetFileAttributesW, saving a few calls.
420
    DWORD orig_attributes = attributes;
421
    attributes &= ~FILE_ATTRIBUTE_READONLY;
422
    if ((perms & 0222) == 0)
423
      attributes |= FILE_ATTRIBUTE_READONLY;
424
    if (attributes != orig_attributes && !SetFileAttributesW(path, attributes))
425
      return set_errno();
426
  }
427
  return 0;
428
}
429
430
int fchmod(int fd, int perms) {
431
  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
432
  return fchmod_handle(h, perms);
433
}
434
435
#define MAX_SYMLINK_SIZE MAXIMUM_REPARSE_DATA_BUFFER_SIZE
436
using SSizeT = ::int64_t;
437
438
SSizeT readlink(const wchar_t *path, wchar_t *ret_buf, size_t bufsize) {
439
  uint8_t buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
440
  detail::WinHandle h(path, FILE_READ_ATTRIBUTES, FILE_FLAG_OPEN_REPARSE_POINT);
441
  if (!h)
442
    return set_errno();
443
  DWORD out;
444
  if (!DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, nullptr, 0, buf, sizeof(buf),
445
                       &out, 0))
446
    return set_errno();
447
  const auto *reparse = reinterpret_cast<LIBCPP_REPARSE_DATA_BUFFER *>(buf);
448
  size_t path_buf_offset = offsetof(LIBCPP_REPARSE_DATA_BUFFER,
449
                                    SymbolicLinkReparseBuffer.PathBuffer[0]);
450
  if (out < path_buf_offset) {
451
    errno = EINVAL;
452
    return -1;
453
  }
454
  if (reparse->ReparseTag != IO_REPARSE_TAG_SYMLINK) {
455
    errno = EINVAL;
456
    return -1;
457
  }
458
  const auto &symlink = reparse->SymbolicLinkReparseBuffer;
459
  unsigned short name_offset, name_length;
460
  if (symlink.PrintNameLength == 0) {
461
    name_offset = symlink.SubstituteNameOffset;
462
    name_length = symlink.SubstituteNameLength;
463
  } else {
464
    name_offset = symlink.PrintNameOffset;
465
    name_length = symlink.PrintNameLength;
466
  }
467
  // name_offset/length are expressed in bytes, not in wchar_t
468
  if (path_buf_offset + name_offset + name_length > out) {
469
    errno = EINVAL;
470
    return -1;
471
  }
472
  if (name_length / sizeof(wchar_t) > bufsize) {
473
    errno = ENOMEM;
474
    return -1;
475
  }
476
  memcpy(ret_buf, &symlink.PathBuffer[name_offset / sizeof(wchar_t)],
477
         name_length);
478
  return name_length / sizeof(wchar_t);
479
}
480
481
#else
482
0
int symlink_file(const char *oldname, const char *newname) {
483
0
  return ::symlink(oldname, newname);
484
0
}
485
0
int symlink_dir(const char *oldname, const char *newname) {
486
0
  return ::symlink(oldname, newname);
487
0
}
488
using ::chdir;
489
using ::close;
490
using ::fchmod;
491
#if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_FDCWD)
492
using ::fchmodat;
493
#endif
494
using ::fstat;
495
using ::ftruncate;
496
using ::getcwd;
497
using ::link;
498
using ::lstat;
499
using ::mkdir;
500
using ::open;
501
using ::readlink;
502
using ::realpath;
503
using ::remove;
504
using ::rename;
505
using ::stat;
506
using ::statvfs;
507
using ::truncate;
508
509
0
#define O_BINARY 0
510
511
using StatVFS = struct statvfs;
512
using ModeT = ::mode_t;
513
using SSizeT = ::ssize_t;
514
515
#endif
516
517
} // namespace
518
} // end namespace detail
519
520
_LIBCPP_END_NAMESPACE_FILESYSTEM
521
522
#endif // POSIX_COMPAT_H