lib/stat-w32.c

   1 /* Core of implementation of fstat and stat for native Windows.
   2    Copyright (C) 2017-2018 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible.  */
  18
  19 #include <config.h>
  20
  21 #if defined _WIN32 && ! defined __CYGWIN__
  22
  23 /* Ensure that <windows.h> defines FILE_ID_INFO.  */
  24 #undef _WIN32_WINNT
  25 #define _WIN32_WINNT _WIN32_WINNT_WIN8
  26
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <errno.h>
  30 #include <limits.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <windows.h>
  34
  35 /* Specification.  */
  36 #include "stat-w32.h"
  37
  38 #include "pathmax.h"
  39 #include "verify.h"
  40
  41 /* Avoid warnings from gcc -Wcast-function-type.  */
  42 #define GetProcAddress \
  43   (void *) GetProcAddress
  44
  45 #if _GL_WINDOWS_STAT_INODES == 2
  46 /* GetFileInformationByHandleEx was introduced only in Windows Vista.  */
  47 typedef DWORD (WINAPI * GetFileInformationByHandleExFuncType) (HANDLE hFile,
  48                                                                FILE_INFO_BY_HANDLE_CLASS fiClass,
  49                                                                LPVOID lpBuffer,
  50                                                                DWORD dwBufferSize);
  51 static GetFileInformationByHandleExFuncType GetFileInformationByHandleExFunc = NULL;
  52 #endif
  53 /* GetFinalPathNameByHandle was introduced only in Windows Vista.  */
  54 typedef DWORD (WINAPI * GetFinalPathNameByHandleFuncType) (HANDLE hFile,
  55                                                            LPTSTR lpFilePath,
  56                                                            DWORD lenFilePath,
  57                                                            DWORD dwFlags);
  58 static GetFinalPathNameByHandleFuncType GetFinalPathNameByHandleFunc = NULL;
  59 static BOOL initialized = FALSE;
  60
  61 static void
  62 initialize (void)
  63 {
  64   HMODULE kernel32 = LoadLibrary ("kernel32.dll");
  65   if (kernel32 != NULL)
  66     {
  67 #if _GL_WINDOWS_STAT_INODES == 2
  68       GetFileInformationByHandleExFunc =
  69         (GetFileInformationByHandleExFuncType) GetProcAddress (kernel32, "GetFileInformationByHandleEx");
  70 #endif
  71       GetFinalPathNameByHandleFunc =
  72         (GetFinalPathNameByHandleFuncType) GetProcAddress (kernel32, "GetFinalPathNameByHandleA");
  73     }
  74   initialized = TRUE;
  75 }
  76
  77 /* Converts a FILETIME to GMT time since 1970-01-01 00:00:00.  */
  78 #if _GL_WINDOWS_STAT_TIMESPEC
  79 struct timespec
  80 _gl_convert_FILETIME_to_timespec (const FILETIME *ft)
  81 {
  82   struct timespec result;
  83   /* FILETIME: <https://msdn.microsoft.com/en-us/library/ms724284.aspx> */
  84   unsigned long long since_1601 =
  85     ((unsigned long long) ft->dwHighDateTime << 32)
  86     | (unsigned long long) ft->dwLowDateTime;
  87   if (since_1601 == 0)
  88     {
  89       result.tv_sec = 0;
  90       result.tv_nsec = 0;
  91     }
  92   else
  93     {
  94       /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89
  95          leap years, in total 134774 days.  */
  96       unsigned long long since_1970 =
  97         since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;
  98       result.tv_sec = since_1970 / (unsigned long long) 10000000;
  99       result.tv_nsec = (unsigned long) (since_1970 % (unsigned long long) 10000000) * 100;
 100     }
 101   return result;
 102 }
 103 #else
 104 time_t
 105 _gl_convert_FILETIME_to_POSIX (const FILETIME *ft)
 106 {
 107   /* FILETIME: <https://msdn.microsoft.com/en-us/library/ms724284.aspx> */
 108   unsigned long long since_1601 =
 109     ((unsigned long long) ft->dwHighDateTime << 32)
 110     | (unsigned long long) ft->dwLowDateTime;
 111   if (since_1601 == 0)
 112     return 0;
 113   else
 114     {
 115       /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89
 116          leap years, in total 134774 days.  */
 117       unsigned long long since_1970 =
 118         since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;
 119       return since_1970 / (unsigned long long) 10000000;
 120     }
 121 }
 122 #endif
 123
 124 /* Fill *BUF with information about the file designated by H.
 125    PATH is the file name, if known, otherwise NULL.
 126    Return 0 if successful, or -1 with errno set upon failure.  */
 127 int
 128 _gl_fstat_by_handle (HANDLE h, const char *path, struct stat *buf)
 129 {
 130   /* GetFileType
 131      <https://msdn.microsoft.com/en-us/library/aa364960.aspx> */
 132   DWORD type = GetFileType (h);
 133   if (type == FILE_TYPE_DISK)
 134     {
 135       if (!initialized)
 136         initialize ();
 137
 138       /* st_mode can be determined through
 139          GetFileAttributesEx
 140          <https://msdn.microsoft.com/en-us/library/aa364946.aspx>
 141          <https://msdn.microsoft.com/en-us/library/aa365739.aspx>
 142          or through
 143          GetFileInformationByHandle
 144          <https://msdn.microsoft.com/en-us/library/aa364952.aspx>
 145          <https://msdn.microsoft.com/en-us/library/aa363788.aspx>
 146          or through
 147          GetFileInformationByHandleEx with argument FileBasicInfo
 148          <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 149          <https://msdn.microsoft.com/en-us/library/aa364217.aspx>
 150          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 151       BY_HANDLE_FILE_INFORMATION info;
 152       if (! GetFileInformationByHandle (h, &info))
 153         goto failed;
 154
 155       /* Test for error conditions before starting to fill *buf.  */
 156       if (sizeof (buf->st_size) <= 4 && info.nFileSizeHigh > 0)
 157         {
 158           errno = EOVERFLOW;
 159           return -1;
 160         }
 161
 162 #if _GL_WINDOWS_STAT_INODES
 163       /* st_ino can be determined through
 164          GetFileInformationByHandle
 165          <https://msdn.microsoft.com/en-us/library/aa364952.aspx>
 166          <https://msdn.microsoft.com/en-us/library/aa363788.aspx>
 167          as 64 bits, or through
 168          GetFileInformationByHandleEx with argument FileIdInfo
 169          <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 170          <https://msdn.microsoft.com/en-us/library/hh802691.aspx>
 171          as 128 bits.
 172          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_WIN8 or higher.  */
 173       /* Experiments show that GetFileInformationByHandleEx does not provide
 174          much more information than GetFileInformationByHandle:
 175            * The dwVolumeSerialNumber from GetFileInformationByHandle is equal
 176              to the low 32 bits of the 64-bit VolumeSerialNumber from
 177              GetFileInformationByHandleEx, and is apparently sufficient for
 178              identifying the device.
 179            * The nFileIndex from GetFileInformationByHandle is equal to the low
 180              64 bits of the 128-bit FileId from GetFileInformationByHandleEx,
 181              and the high 64 bits of this 128-bit FileId are zero.
 182            * On a FAT file system, GetFileInformationByHandleEx fails with error
 183              ERROR_INVALID_PARAMETER, whereas GetFileInformationByHandle
 184              succeeds.
 185            * On a CIFS/SMB file system, GetFileInformationByHandleEx fails with
 186              error ERROR_INVALID_LEVEL, whereas GetFileInformationByHandle
 187              succeeds.  */
 188 # if _GL_WINDOWS_STAT_INODES == 2
 189       if (GetFileInformationByHandleExFunc != NULL)
 190         {
 191           FILE_ID_INFO id;
 192           if (GetFileInformationByHandleExFunc (h, FileIdInfo, &id, sizeof (id)))
 193             {
 194               buf->st_dev = id.VolumeSerialNumber;
 195               verify (sizeof (ino_t) == sizeof (id.FileId));
 196               memcpy (&buf->st_ino, &id.FileId, sizeof (ino_t));
 197               goto ino_done;
 198             }
 199           else
 200             {
 201               switch (GetLastError ())
 202                 {
 203                 case ERROR_INVALID_PARAMETER: /* older Windows version, or FAT */
 204                 case ERROR_INVALID_LEVEL: /* CIFS/SMB file system */
 205                   goto fallback;
 206                 default:
 207                   goto failed;
 208                 }
 209             }
 210         }
 211      fallback: ;
 212       /* Fallback for older Windows versions.  */
 213       buf->st_dev = info.dwVolumeSerialNumber;
 214       buf->st_ino._gl_ino[0] = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;
 215       buf->st_ino._gl_ino[1] = 0;
 216      ino_done: ;
 217 # else /* _GL_WINDOWS_STAT_INODES == 1 */
 218       buf->st_dev = info.dwVolumeSerialNumber;
 219       buf->st_ino = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;
 220 # endif
 221 #else
 222       /* st_ino is not wide enough for identifying a file on a device.
 223          Without st_ino, st_dev is pointless.  */
 224       buf->st_dev = 0;
 225       buf->st_ino = 0;
 226 #endif
 227
 228       /* st_mode.  */
 229       unsigned int mode =
 230         /* XXX How to handle FILE_ATTRIBUTE_REPARSE_POINT ?  */
 231         ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? _S_IFDIR | S_IEXEC_UGO : _S_IFREG)
 232         | S_IREAD_UGO
 233         | ((info.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? 0 : S_IWRITE_UGO);
 234       if (!(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
 235         {
 236           /* Determine whether the file is executable by looking at the file
 237              name suffix.
 238              If the file name is already known, use it. Otherwise, for
 239              non-empty files, it can be determined through
 240              GetFinalPathNameByHandle
 241              <https://msdn.microsoft.com/en-us/library/aa364962.aspx>
 242              or through
 243              GetFileInformationByHandleEx with argument FileNameInfo
 244              <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 245              <https://msdn.microsoft.com/en-us/library/aa364388.aspx>
 246              Both require -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 247           if (info.nFileSizeHigh > 0 || info.nFileSizeLow > 0)
 248             {
 249               char fpath[PATH_MAX];
 250               if (path != NULL
 251                   || (GetFinalPathNameByHandleFunc != NULL
 252                       && GetFinalPathNameByHandleFunc (h, fpath, sizeof (fpath), VOLUME_NAME_NONE)
 253                          < sizeof (fpath)
 254                       && (path = fpath, 1)))
 255                 {
 256                   const char *last_dot = NULL;
 257                   const char *p;
 258                   for (p = path; *p != '\0'; p++)
 259                     if (*p == '.')
 260                       last_dot = p;
 261                   if (last_dot != NULL)
 262                     {
 263                       const char *suffix = last_dot + 1;
 264                       if (_stricmp (suffix, "exe") == 0
 265                           || _stricmp (suffix, "bat") == 0
 266                           || _stricmp (suffix, "cmd") == 0
 267                           || _stricmp (suffix, "com") == 0)
 268                         mode |= S_IEXEC_UGO;
 269                     }
 270                 }
 271               else
 272                 /* Cannot determine file name.  Pretend that it is executable.  */
 273                 mode |= S_IEXEC_UGO;
 274             }
 275         }
 276       buf->st_mode = mode;
 277
 278       /* st_nlink can be determined through
 279          GetFileInformationByHandle
 280          <https://msdn.microsoft.com/en-us/library/aa364952.aspx>
 281          <https://msdn.microsoft.com/en-us/library/aa363788.aspx>
 282          or through
 283          GetFileInformationByHandleEx with argument FileStandardInfo
 284          <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 285          <https://msdn.microsoft.com/en-us/library/aa364401.aspx>
 286          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 287       buf->st_nlink = (info.nNumberOfLinks > SHRT_MAX ? SHRT_MAX : info.nNumberOfLinks);
 288
 289       /* There's no easy way to map the Windows SID concept to an integer.  */
 290       buf->st_uid = 0;
 291       buf->st_gid = 0;
 292
 293       /* st_rdev is irrelevant for normal files and directories.  */
 294       buf->st_rdev = 0;
 295
 296       /* st_size can be determined through
 297          GetFileSizeEx
 298          <https://msdn.microsoft.com/en-us/library/aa364957.aspx>
 299          or through
 300          GetFileAttributesEx
 301          <https://msdn.microsoft.com/en-us/library/aa364946.aspx>
 302          <https://msdn.microsoft.com/en-us/library/aa365739.aspx>
 303          or through
 304          GetFileInformationByHandle
 305          <https://msdn.microsoft.com/en-us/library/aa364952.aspx>
 306          <https://msdn.microsoft.com/en-us/library/aa363788.aspx>
 307          or through
 308          GetFileInformationByHandleEx with argument FileStandardInfo
 309          <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 310          <https://msdn.microsoft.com/en-us/library/aa364401.aspx>
 311          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 312       if (sizeof (buf->st_size) <= 4)
 313         /* Range check already done above.  */
 314         buf->st_size = info.nFileSizeLow;
 315       else
 316         buf->st_size = ((long long) info.nFileSizeHigh << 32) | (long long) info.nFileSizeLow;
 317
 318       /* st_atime, st_mtime, st_ctime can be determined through
 319          GetFileTime
 320          <https://msdn.microsoft.com/en-us/library/ms724320.aspx>
 321          or through
 322          GetFileAttributesEx
 323          <https://msdn.microsoft.com/en-us/library/aa364946.aspx>
 324          <https://msdn.microsoft.com/en-us/library/aa365739.aspx>
 325          or through
 326          GetFileInformationByHandle
 327          <https://msdn.microsoft.com/en-us/library/aa364952.aspx>
 328          <https://msdn.microsoft.com/en-us/library/aa363788.aspx>
 329          or through
 330          GetFileInformationByHandleEx with argument FileBasicInfo
 331          <https://msdn.microsoft.com/en-us/library/aa364953.aspx>
 332          <https://msdn.microsoft.com/en-us/library/aa364217.aspx>
 333          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 334 #if _GL_WINDOWS_STAT_TIMESPEC
 335       buf->st_atim = _gl_convert_FILETIME_to_timespec (&info.ftLastAccessTime);
 336       buf->st_mtim = _gl_convert_FILETIME_to_timespec (&info.ftLastWriteTime);
 337       buf->st_ctim = _gl_convert_FILETIME_to_timespec (&info.ftCreationTime);
 338 #else
 339       buf->st_atime = _gl_convert_FILETIME_to_POSIX (&info.ftLastAccessTime);
 340       buf->st_mtime = _gl_convert_FILETIME_to_POSIX (&info.ftLastWriteTime);
 341       buf->st_ctime = _gl_convert_FILETIME_to_POSIX (&info.ftCreationTime);
 342 #endif
 343
 344       return 0;
 345     }
 346   else if (type == FILE_TYPE_CHAR || type == FILE_TYPE_PIPE)
 347     {
 348       buf->st_dev = 0;
 349 #if _GL_WINDOWS_STAT_INODES == 2
 350       buf->st_ino._gl_ino[0] = buf->st_ino._gl_ino[1] = 0;
 351 #else
 352       buf->st_ino = 0;
 353 #endif
 354       buf->st_mode = (type == FILE_TYPE_PIPE ? _S_IFIFO : _S_IFCHR);
 355       buf->st_nlink = 1;
 356       buf->st_uid = 0;
 357       buf->st_gid = 0;
 358       buf->st_rdev = 0;
 359       if (type == FILE_TYPE_PIPE)
 360         {
 361           /* PeekNamedPipe
 362              <https://msdn.microsoft.com/en-us/library/aa365779.aspx> */
 363           DWORD bytes_available;
 364           if (PeekNamedPipe (h, NULL, 0, NULL, &bytes_available, NULL))
 365             buf->st_size = bytes_available;
 366           else
 367             buf->st_size = 0;
 368         }
 369       else
 370         buf->st_size = 0;
 371 #if _GL_WINDOWS_STAT_TIMESPEC
 372       buf->st_atim.tv_sec = 0; buf->st_atim.tv_nsec = 0;
 373       buf->st_mtim.tv_sec = 0; buf->st_mtim.tv_nsec = 0;
 374       buf->st_ctim.tv_sec = 0; buf->st_ctim.tv_nsec = 0;
 375 #else
 376       buf->st_atime = 0;
 377       buf->st_mtime = 0;
 378       buf->st_ctime = 0;
 379 #endif
 380       return 0;
 381     }
 382   else
 383     {
 384       errno = ENOENT;
 385       return -1;
 386     }
 387
 388  failed:
 389   {
 390     DWORD error = GetLastError ();
 391     #if 0
 392     fprintf (stderr, "_gl_fstat_by_handle error 0x%x\n", (unsigned int) error);
 393     #endif
 394     switch (error)
 395       {
 396       case ERROR_ACCESS_DENIED:
 397       case ERROR_SHARING_VIOLATION:
 398         errno = EACCES;
 399         break;
 400
 401       case ERROR_OUTOFMEMORY:
 402         errno = ENOMEM;
 403         break;
 404
 405       case ERROR_WRITE_FAULT:
 406       case ERROR_READ_FAULT:
 407       case ERROR_GEN_FAILURE:
 408         errno = EIO;
 409         break;
 410
 411       default:
 412         errno = EINVAL;
 413         break;
 414       }
 415     return -1;
 416   }
 417 }
 418
 419 #else
 420
 421 /* This declaration is solely to ensure that after preprocessing
 422    this file is never empty.  */
 423 typedef int dummy;
 424
 425 #endif