lib/stat-w32.c

   1 /* Core of implementation of fstat and stat for native Windows.
   2    Copyright (C) 2017-2020 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 #if !defined _WIN32_WINNT || (_WIN32_WINNT < _WIN32_WINNT_WIN8)
  25 # undef _WIN32_WINNT
  26 # define _WIN32_WINNT _WIN32_WINNT_WIN8
  27 #endif
  28
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <errno.h>
  32 #include <limits.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35 #include <windows.h>
  36
  37 /* Specification.  */
  38 #include "stat-w32.h"
  39
  40 #include "pathmax.h"
  41 #include "verify.h"
  42
  43 /* Don't assume that UNICODE is not defined.  */
  44 #undef LoadLibrary
  45 #define LoadLibrary LoadLibraryA
  46 #undef GetFinalPathNameByHandle
  47 #define GetFinalPathNameByHandle GetFinalPathNameByHandleA
  48
  49 #if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)
  50
  51 /* Avoid warnings from gcc -Wcast-function-type.  */
  52 # define GetProcAddress \
  53    (void *) GetProcAddress
  54
  55 # if _GL_WINDOWS_STAT_INODES == 2
  56 /* GetFileInformationByHandleEx was introduced only in Windows Vista.  */
  57 typedef DWORD (WINAPI * GetFileInformationByHandleExFuncType) (HANDLE hFile,
  58                                                                FILE_INFO_BY_HANDLE_CLASS fiClass,
  59                                                                LPVOID lpBuffer,
  60                                                                DWORD dwBufferSize);
  61 static GetFileInformationByHandleExFuncType GetFileInformationByHandleExFunc = NULL;
  62 # endif
  63 /* GetFinalPathNameByHandle was introduced only in Windows Vista.  */
  64 typedef DWORD (WINAPI * GetFinalPathNameByHandleFuncType) (HANDLE hFile,
  65                                                            LPSTR lpFilePath,
  66                                                            DWORD lenFilePath,
  67                                                            DWORD dwFlags);
  68 static GetFinalPathNameByHandleFuncType GetFinalPathNameByHandleFunc = NULL;
  69 static BOOL initialized = FALSE;
  70
  71 static void
  72 initialize (void)
  73 {
  74   HMODULE kernel32 = LoadLibrary ("kernel32.dll");
  75   if (kernel32 != NULL)
  76     {
  77 # if _GL_WINDOWS_STAT_INODES == 2
  78       GetFileInformationByHandleExFunc =
  79         (GetFileInformationByHandleExFuncType) GetProcAddress (kernel32, "GetFileInformationByHandleEx");
  80 # endif
  81       GetFinalPathNameByHandleFunc =
  82         (GetFinalPathNameByHandleFuncType) GetProcAddress (kernel32, "GetFinalPathNameByHandleA");
  83     }
  84   initialized = TRUE;
  85 }
  86
  87 #else
  88
  89 # define GetFileInformationByHandleExFunc GetFileInformationByHandleEx
  90 # define GetFinalPathNameByHandleFunc GetFinalPathNameByHandle
  91
  92 #endif
  93
  94 /* Converts a FILETIME to GMT time since 1970-01-01 00:00:00.  */
  95 #if _GL_WINDOWS_STAT_TIMESPEC
  96 struct timespec
  97 _gl_convert_FILETIME_to_timespec (const FILETIME *ft)
  98 {
  99   struct timespec result;
 100   /* FILETIME: <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime> */
 101   unsigned long long since_1601 =
 102     ((unsigned long long) ft->dwHighDateTime << 32)
 103     | (unsigned long long) ft->dwLowDateTime;
 104   if (since_1601 == 0)
 105     {
 106       result.tv_sec = 0;
 107       result.tv_nsec = 0;
 108     }
 109   else
 110     {
 111       /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89
 112          leap years, in total 134774 days.  */
 113       unsigned long long since_1970 =
 114         since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;
 115       result.tv_sec = since_1970 / (unsigned long long) 10000000;
 116       result.tv_nsec = (unsigned long) (since_1970 % (unsigned long long) 10000000) * 100;
 117     }
 118   return result;
 119 }
 120 #else
 121 time_t
 122 _gl_convert_FILETIME_to_POSIX (const FILETIME *ft)
 123 {
 124   /* FILETIME: <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime> */
 125   unsigned long long since_1601 =
 126     ((unsigned long long) ft->dwHighDateTime << 32)
 127     | (unsigned long long) ft->dwLowDateTime;
 128   if (since_1601 == 0)
 129     return 0;
 130   else
 131     {
 132       /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89
 133          leap years, in total 134774 days.  */
 134       unsigned long long since_1970 =
 135         since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;
 136       return since_1970 / (unsigned long long) 10000000;
 137     }
 138 }
 139 #endif
 140
 141 /* Fill *BUF with information about the file designated by H.
 142    PATH is the file name, if known, otherwise NULL.
 143    Return 0 if successful, or -1 with errno set upon failure.  */
 144 int
 145 _gl_fstat_by_handle (HANDLE h, const char *path, struct stat *buf)
 146 {
 147   /* GetFileType
 148      <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfiletype> */
 149   DWORD type = GetFileType (h);
 150   if (type == FILE_TYPE_DISK)
 151     {
 152 #if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)
 153       if (!initialized)
 154         initialize ();
 155 #endif
 156
 157       /* st_mode can be determined through
 158          GetFileAttributesEx
 159          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>
 160          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>
 161          or through
 162          GetFileInformationByHandle
 163          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>
 164          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>
 165          or through
 166          GetFileInformationByHandleEx with argument FileBasicInfo
 167          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 168          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_basic_info>
 169          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 170       BY_HANDLE_FILE_INFORMATION info;
 171       if (! GetFileInformationByHandle (h, &info))
 172         goto failed;
 173
 174       /* Test for error conditions before starting to fill *buf.  */
 175       if (sizeof (buf->st_size) <= 4 && info.nFileSizeHigh > 0)
 176         {
 177           errno = EOVERFLOW;
 178           return -1;
 179         }
 180
 181 #if _GL_WINDOWS_STAT_INODES
 182       /* st_ino can be determined through
 183          GetFileInformationByHandle
 184          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>
 185          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>
 186          as 64 bits, or through
 187          GetFileInformationByHandleEx with argument FileIdInfo
 188          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 189          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_id_info>
 190          as 128 bits.
 191          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_WIN8 or higher.  */
 192       /* Experiments show that GetFileInformationByHandleEx does not provide
 193          much more information than GetFileInformationByHandle:
 194            * The dwVolumeSerialNumber from GetFileInformationByHandle is equal
 195              to the low 32 bits of the 64-bit VolumeSerialNumber from
 196              GetFileInformationByHandleEx, and is apparently sufficient for
 197              identifying the device.
 198            * The nFileIndex from GetFileInformationByHandle is equal to the low
 199              64 bits of the 128-bit FileId from GetFileInformationByHandleEx,
 200              and the high 64 bits of this 128-bit FileId are zero.
 201            * On a FAT file system, GetFileInformationByHandleEx fails with error
 202              ERROR_INVALID_PARAMETER, whereas GetFileInformationByHandle
 203              succeeds.
 204            * On a CIFS/SMB file system, GetFileInformationByHandleEx fails with
 205              error ERROR_INVALID_LEVEL, whereas GetFileInformationByHandle
 206              succeeds.  */
 207 # if _GL_WINDOWS_STAT_INODES == 2
 208       if (GetFileInformationByHandleExFunc != NULL)
 209         {
 210           FILE_ID_INFO id;
 211           if (GetFileInformationByHandleExFunc (h, FileIdInfo, &id, sizeof (id)))
 212             {
 213               buf->st_dev = id.VolumeSerialNumber;
 214               verify (sizeof (ino_t) == sizeof (id.FileId));
 215               memcpy (&buf->st_ino, &id.FileId, sizeof (ino_t));
 216               goto ino_done;
 217             }
 218           else
 219             {
 220               switch (GetLastError ())
 221                 {
 222                 case ERROR_INVALID_PARAMETER: /* older Windows version, or FAT */
 223                 case ERROR_INVALID_LEVEL: /* CIFS/SMB file system */
 224                   goto fallback;
 225                 default:
 226                   goto failed;
 227                 }
 228             }
 229         }
 230      fallback: ;
 231       /* Fallback for older Windows versions.  */
 232       buf->st_dev = info.dwVolumeSerialNumber;
 233       buf->st_ino._gl_ino[0] = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;
 234       buf->st_ino._gl_ino[1] = 0;
 235      ino_done: ;
 236 # else /* _GL_WINDOWS_STAT_INODES == 1 */
 237       buf->st_dev = info.dwVolumeSerialNumber;
 238       buf->st_ino = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;
 239 # endif
 240 #else
 241       /* st_ino is not wide enough for identifying a file on a device.
 242          Without st_ino, st_dev is pointless.  */
 243       buf->st_dev = 0;
 244       buf->st_ino = 0;
 245 #endif
 246
 247       /* st_mode.  */
 248       unsigned int mode =
 249         /* XXX How to handle FILE_ATTRIBUTE_REPARSE_POINT ?  */
 250         ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? _S_IFDIR | S_IEXEC_UGO : _S_IFREG)
 251         | S_IREAD_UGO
 252         | ((info.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? 0 : S_IWRITE_UGO);
 253       if (!(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
 254         {
 255           /* Determine whether the file is executable by looking at the file
 256              name suffix.
 257              If the file name is already known, use it. Otherwise, for
 258              non-empty files, it can be determined through
 259              GetFinalPathNameByHandle
 260              <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfinalpathnamebyhandlea>
 261              or through
 262              GetFileInformationByHandleEx with argument FileNameInfo
 263              <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 264              <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_name_info>
 265              Both require -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 266           if (info.nFileSizeHigh > 0 || info.nFileSizeLow > 0)
 267             {
 268               char fpath[PATH_MAX];
 269               if (path != NULL
 270                   || (GetFinalPathNameByHandleFunc != NULL
 271                       && GetFinalPathNameByHandleFunc (h, fpath, sizeof (fpath), VOLUME_NAME_NONE)
 272                          < sizeof (fpath)
 273                       && (path = fpath, 1)))
 274                 {
 275                   const char *last_dot = NULL;
 276                   const char *p;
 277                   for (p = path; *p != '\0'; p++)
 278                     if (*p == '.')
 279                       last_dot = p;
 280                   if (last_dot != NULL)
 281                     {
 282                       const char *suffix = last_dot + 1;
 283                       if (_stricmp (suffix, "exe") == 0
 284                           || _stricmp (suffix, "bat") == 0
 285                           || _stricmp (suffix, "cmd") == 0
 286                           || _stricmp (suffix, "com") == 0)
 287                         mode |= S_IEXEC_UGO;
 288                     }
 289                 }
 290               else
 291                 /* Cannot determine file name.  Pretend that it is executable.  */
 292                 mode |= S_IEXEC_UGO;
 293             }
 294         }
 295       buf->st_mode = mode;
 296
 297       /* st_nlink can be determined through
 298          GetFileInformationByHandle
 299          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>
 300          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>
 301          or through
 302          GetFileInformationByHandleEx with argument FileStandardInfo
 303          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 304          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_standard_info>
 305          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 306       buf->st_nlink = (info.nNumberOfLinks > SHRT_MAX ? SHRT_MAX : info.nNumberOfLinks);
 307
 308       /* There's no easy way to map the Windows SID concept to an integer.  */
 309       buf->st_uid = 0;
 310       buf->st_gid = 0;
 311
 312       /* st_rdev is irrelevant for normal files and directories.  */
 313       buf->st_rdev = 0;
 314
 315       /* st_size can be determined through
 316          GetFileSizeEx
 317          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfilesizeex>
 318          or through
 319          GetFileAttributesEx
 320          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>
 321          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>
 322          or through
 323          GetFileInformationByHandle
 324          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>
 325          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>
 326          or through
 327          GetFileInformationByHandleEx with argument FileStandardInfo
 328          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 329          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_standard_info>
 330          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 331       if (sizeof (buf->st_size) <= 4)
 332         /* Range check already done above.  */
 333         buf->st_size = info.nFileSizeLow;
 334       else
 335         buf->st_size = ((long long) info.nFileSizeHigh << 32) | (long long) info.nFileSizeLow;
 336
 337       /* st_atime, st_mtime, st_ctime can be determined through
 338          GetFileTime
 339          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfiletime>
 340          or through
 341          GetFileAttributesEx
 342          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>
 343          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>
 344          or through
 345          GetFileInformationByHandle
 346          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>
 347          <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>
 348          or through
 349          GetFileInformationByHandleEx with argument FileBasicInfo
 350          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>
 351          <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_basic_info>
 352          The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */
 353 #if _GL_WINDOWS_STAT_TIMESPEC
 354       buf->st_atim = _gl_convert_FILETIME_to_timespec (&info.ftLastAccessTime);
 355       buf->st_mtim = _gl_convert_FILETIME_to_timespec (&info.ftLastWriteTime);
 356       buf->st_ctim = _gl_convert_FILETIME_to_timespec (&info.ftCreationTime);
 357 #else
 358       buf->st_atime = _gl_convert_FILETIME_to_POSIX (&info.ftLastAccessTime);
 359       buf->st_mtime = _gl_convert_FILETIME_to_POSIX (&info.ftLastWriteTime);
 360       buf->st_ctime = _gl_convert_FILETIME_to_POSIX (&info.ftCreationTime);
 361 #endif
 362
 363       return 0;
 364     }
 365   else if (type == FILE_TYPE_CHAR || type == FILE_TYPE_PIPE)
 366     {
 367       buf->st_dev = 0;
 368 #if _GL_WINDOWS_STAT_INODES == 2
 369       buf->st_ino._gl_ino[0] = buf->st_ino._gl_ino[1] = 0;
 370 #else
 371       buf->st_ino = 0;
 372 #endif
 373       buf->st_mode = (type == FILE_TYPE_PIPE ? _S_IFIFO : _S_IFCHR);
 374       buf->st_nlink = 1;
 375       buf->st_uid = 0;
 376       buf->st_gid = 0;
 377       buf->st_rdev = 0;
 378       if (type == FILE_TYPE_PIPE)
 379         {
 380           /* PeekNamedPipe
 381              <https://msdn.microsoft.com/en-us/library/aa365779.aspx> */
 382           DWORD bytes_available;
 383           if (PeekNamedPipe (h, NULL, 0, NULL, &bytes_available, NULL))
 384             buf->st_size = bytes_available;
 385           else
 386             buf->st_size = 0;
 387         }
 388       else
 389         buf->st_size = 0;
 390 #if _GL_WINDOWS_STAT_TIMESPEC
 391       buf->st_atim.tv_sec = 0; buf->st_atim.tv_nsec = 0;
 392       buf->st_mtim.tv_sec = 0; buf->st_mtim.tv_nsec = 0;
 393       buf->st_ctim.tv_sec = 0; buf->st_ctim.tv_nsec = 0;
 394 #else
 395       buf->st_atime = 0;
 396       buf->st_mtime = 0;
 397       buf->st_ctime = 0;
 398 #endif
 399       return 0;
 400     }
 401   else
 402     {
 403       errno = ENOENT;
 404       return -1;
 405     }
 406
 407  failed:
 408   {
 409     DWORD error = GetLastError ();
 410     #if 0
 411     fprintf (stderr, "_gl_fstat_by_handle error 0x%x\n", (unsigned int) error);
 412     #endif
 413     switch (error)
 414       {
 415       case ERROR_ACCESS_DENIED:
 416       case ERROR_SHARING_VIOLATION:
 417         errno = EACCES;
 418         break;
 419
 420       case ERROR_OUTOFMEMORY:
 421         errno = ENOMEM;
 422         break;
 423
 424       case ERROR_WRITE_FAULT:
 425       case ERROR_READ_FAULT:
 426       case ERROR_GEN_FAILURE:
 427         errno = EIO;
 428         break;
 429
 430       default:
 431         errno = EINVAL;
 432         break;
 433       }
 434     return -1;
 435   }
 436 }
 437
 438 #else
 439
 440 /* This declaration is solely to ensure that after preprocessing
 441    this file is never empty.  */
 442 typedef int dummy;
 443
 444 #endif