1/* Work around platform bugs in stat.
2   Copyright (C) 2009-2022 Free Software Foundation, Inc.
3
4   This file is free software: you can redistribute it and/or modify
5   it under the terms of the GNU Lesser General Public License as
6   published by the Free Software Foundation; either version 2.1 of the
7   License, or (at your option) any later version.
8
9   This file 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 Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public License
15   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
16
17/* Written by Eric Blake and Bruno Haible.  */
18
19/* If the user's config.h happens to include <sys/stat.h>, let it include only
20   the system's <sys/stat.h> here, so that orig_stat doesn't recurse to
21   rpl_stat.  */
22#define __need_system_sys_stat_h
23#include <config.h>
24
25/* Get the original definition of stat.  It might be defined as a macro.  */
26#include <sys/types.h>
27#include <sys/stat.h>
28#undef __need_system_sys_stat_h
29
30#if defined _WIN32 && ! defined __CYGWIN__
31# define WINDOWS_NATIVE
32#endif
33
34#if !defined WINDOWS_NATIVE
35
36static int
37orig_stat (const char *filename, struct stat *buf)
38{
39  return stat (filename, buf);
40}
41
42#endif
43
44/* Specification.  */
45#ifdef __osf__
46/* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
47   eliminates this include because of the preliminary #include <sys/stat.h>
48   above.  */
49# include "sys/stat.h"
50#else
51# include <sys/stat.h>
52#endif
53
54#include "stat-time.h"
55
56#include <errno.h>
57#include <limits.h>
58#include <stdbool.h>
59#include <string.h>
60#include "filename.h"
61#include "malloca.h"
62#include "verify.h"
63
64#ifdef WINDOWS_NATIVE
65# define WIN32_LEAN_AND_MEAN
66# include <windows.h>
67# include "stat-w32.h"
68/* Don't assume that UNICODE is not defined.  */
69# undef WIN32_FIND_DATA
70# define WIN32_FIND_DATA WIN32_FIND_DATAA
71# undef CreateFile
72# define CreateFile CreateFileA
73# undef FindFirstFile
74# define FindFirstFile FindFirstFileA
75#endif
76
77#ifdef WINDOWS_NATIVE
78/* Return TRUE if the given file name denotes an UNC root.  */
79static BOOL
80is_unc_root (const char *rname)
81{
82  /* Test whether it has the syntax '\\server\share'.  */
83  if (ISSLASH (rname[0]) && ISSLASH (rname[1]))
84    {
85      /* It starts with two slashes.  Find the next slash.  */
86      const char *p = rname + 2;
87      const char *q = p;
88      while (*q != '\0' && !ISSLASH (*q))
89        q++;
90      if (q > p && *q != '\0')
91        {
92          /* Found the next slash at q.  */
93          q++;
94          const char *r = q;
95          while (*r != '\0' && !ISSLASH (*r))
96            r++;
97          if (r > q && *r == '\0')
98            return TRUE;
99        }
100    }
101  return FALSE;
102}
103#endif
104
105/* Store information about NAME into ST.  Work around bugs with
106   trailing slashes.  Mingw has other bugs (such as st_ino always
107   being 0 on success) which this wrapper does not work around.  But
108   at least this implementation provides the ability to emulate fchdir
109   correctly.  */
110
111int
112rpl_stat (char const *name, struct stat *buf)
113{
114#ifdef WINDOWS_NATIVE
115  /* Fill the fields ourselves, because the original stat function returns
116     values for st_atime, st_mtime, st_ctime that depend on the current time
117     zone.  See
118     <https://lists.gnu.org/r/bug-gnulib/2017-04/msg00134.html>  */
119  /* XXX Should we convert to wchar_t* and prepend '\\?\', in order to work
120     around length limitations
121     <https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file> ?  */
122
123  /* POSIX <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13>
124     specifies: "More than two leading <slash> characters shall be treated as
125     a single <slash> character."  */
126  if (ISSLASH (name[0]) && ISSLASH (name[1]) && ISSLASH (name[2]))
127    {
128      name += 2;
129      while (ISSLASH (name[1]))
130        name++;
131    }
132
133  size_t len = strlen (name);
134  size_t drive_prefix_len = (HAS_DEVICE (name) ? 2 : 0);
135
136  /* Remove trailing slashes (except the very first one, at position
137     drive_prefix_len), but remember their presence.  */
138  size_t rlen;
139  bool check_dir = false;
140
141  rlen = len;
142  while (rlen > drive_prefix_len && ISSLASH (name[rlen-1]))
143    {
144      check_dir = true;
145      if (rlen == drive_prefix_len + 1)
146        break;
147      rlen--;
148    }
149
150  /* Handle '' and 'C:'.  */
151  if (!check_dir && rlen == drive_prefix_len)
152    {
153      errno = ENOENT;
154      return -1;
155    }
156
157  /* Handle '\\'.  */
158  if (rlen == 1 && ISSLASH (name[0]) && len >= 2)
159    {
160      errno = ENOENT;
161      return -1;
162    }
163
164  const char *rname;
165  char *malloca_rname;
166  if (rlen == len)
167    {
168      rname = name;
169      malloca_rname = NULL;
170    }
171  else
172    {
173      malloca_rname = malloca (rlen + 1);
174      if (malloca_rname == NULL)
175        {
176          errno = ENOMEM;
177          return -1;
178        }
179      memcpy (malloca_rname, name, rlen);
180      malloca_rname[rlen] = '\0';
181      rname = malloca_rname;
182    }
183
184  /* There are two ways to get at the requested information:
185       - by scanning the parent directory and examining the relevant
186         directory entry,
187       - by opening the file directly.
188     The first approach fails for root directories (e.g. 'C:\') and
189     UNC root directories (e.g. '\\server\share').
190     The second approach fails for some system files (e.g. 'C:\pagefile.sys'
191     and 'C:\hiberfil.sys'): ERROR_SHARING_VIOLATION.
192     The second approach gives more information (in particular, correct
193     st_dev, st_ino, st_nlink fields).
194     So we use the second approach and, as a fallback except for root and
195     UNC root directories, also the first approach.  */
196  {
197    int ret;
198
199    {
200      /* Approach based on the file.  */
201
202      /* Open a handle to the file.
203         CreateFile
204         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-createfilea>
205         <https://docs.microsoft.com/en-us/windows/desktop/FileIO/creating-and-opening-files>  */
206      HANDLE h =
207        CreateFile (rname,
208                    FILE_READ_ATTRIBUTES,
209                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
210                    NULL,
211                    OPEN_EXISTING,
212                    /* FILE_FLAG_POSIX_SEMANTICS (treat file names that differ only
213                       in case as different) makes sense only when applied to *all*
214                       filesystem operations.  */
215                    FILE_FLAG_BACKUP_SEMANTICS /* | FILE_FLAG_POSIX_SEMANTICS */,
216                    NULL);
217      if (h != INVALID_HANDLE_VALUE)
218        {
219          ret = _gl_fstat_by_handle (h, rname, buf);
220          CloseHandle (h);
221          goto done;
222        }
223    }
224
225    /* Test for root and UNC root directories.  */
226    if ((rlen == drive_prefix_len + 1 && ISSLASH (rname[drive_prefix_len]))
227        || is_unc_root (rname))
228      goto failed;
229
230    /* Fallback.  */
231    {
232      /* Approach based on the directory entry.  */
233
234      if (strchr (rname, '?') != NULL || strchr (rname, '*') != NULL)
235        {
236          /* Other Windows API functions would fail with error
237             ERROR_INVALID_NAME.  */
238          if (malloca_rname != NULL)
239            freea (malloca_rname);
240          errno = ENOENT;
241          return -1;
242        }
243
244      /* Get the details about the directory entry.  This can be done through
245         FindFirstFile
246         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-findfirstfilea>
247         <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-_win32_find_dataa>
248         or through
249         FindFirstFileEx with argument FindExInfoBasic
250         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-findfirstfileexa>
251         <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ne-minwinbase-findex_info_levels>
252         <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-_win32_find_dataa>  */
253      WIN32_FIND_DATA info;
254      HANDLE h = FindFirstFile (rname, &info);
255      if (h == INVALID_HANDLE_VALUE)
256        goto failed;
257
258      /* Test for error conditions before starting to fill *buf.  */
259      if (sizeof (buf->st_size) <= 4 && info.nFileSizeHigh > 0)
260        {
261          FindClose (h);
262          if (malloca_rname != NULL)
263            freea (malloca_rname);
264          errno = EOVERFLOW;
265          return -1;
266        }
267
268# if _GL_WINDOWS_STAT_INODES
269      buf->st_dev = 0;
270#  if _GL_WINDOWS_STAT_INODES == 2
271      buf->st_ino._gl_ino[0] = buf->st_ino._gl_ino[1] = 0;
272#  else /* _GL_WINDOWS_STAT_INODES == 1 */
273      buf->st_ino = 0;
274#  endif
275# else
276      /* st_ino is not wide enough for identifying a file on a device.
277         Without st_ino, st_dev is pointless.  */
278      buf->st_dev = 0;
279      buf->st_ino = 0;
280# endif
281
282      /* st_mode.  */
283      unsigned int mode =
284        /* XXX How to handle FILE_ATTRIBUTE_REPARSE_POINT ?  */
285        ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? _S_IFDIR | S_IEXEC_UGO : _S_IFREG)
286        | S_IREAD_UGO
287        | ((info.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? 0 : S_IWRITE_UGO);
288      if (!(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
289        {
290          /* Determine whether the file is executable by looking at the file
291             name suffix.  */
292          if (info.nFileSizeHigh > 0 || info.nFileSizeLow > 0)
293            {
294              const char *last_dot = NULL;
295              const char *p;
296              for (p = info.cFileName; *p != '\0'; p++)
297                if (*p == '.')
298                  last_dot = p;
299              if (last_dot != NULL)
300                {
301                  const char *suffix = last_dot + 1;
302                  if (_stricmp (suffix, "exe") == 0
303                      || _stricmp (suffix, "bat") == 0
304                      || _stricmp (suffix, "cmd") == 0
305                      || _stricmp (suffix, "com") == 0)
306                    mode |= S_IEXEC_UGO;
307                }
308            }
309        }
310      buf->st_mode = mode;
311
312      /* st_nlink.  Ignore hard links here.  */
313      buf->st_nlink = 1;
314
315      /* There's no easy way to map the Windows SID concept to an integer.  */
316      buf->st_uid = 0;
317      buf->st_gid = 0;
318
319      /* st_rdev is irrelevant for normal files and directories.  */
320      buf->st_rdev = 0;
321
322      /* st_size.  */
323      if (sizeof (buf->st_size) <= 4)
324        /* Range check already done above.  */
325        buf->st_size = info.nFileSizeLow;
326      else
327        buf->st_size = ((long long) info.nFileSizeHigh << 32) | (long long) info.nFileSizeLow;
328
329      /* st_atime, st_mtime, st_ctime.  */
330# if _GL_WINDOWS_STAT_TIMESPEC
331      buf->st_atim = _gl_convert_FILETIME_to_timespec (&info.ftLastAccessTime);
332      buf->st_mtim = _gl_convert_FILETIME_to_timespec (&info.ftLastWriteTime);
333      buf->st_ctim = _gl_convert_FILETIME_to_timespec (&info.ftCreationTime);
334# else
335      buf->st_atime = _gl_convert_FILETIME_to_POSIX (&info.ftLastAccessTime);
336      buf->st_mtime = _gl_convert_FILETIME_to_POSIX (&info.ftLastWriteTime);
337      buf->st_ctime = _gl_convert_FILETIME_to_POSIX (&info.ftCreationTime);
338# endif
339
340      FindClose (h);
341
342      ret = 0;
343    }
344
345   done:
346    if (ret >= 0 && check_dir && !S_ISDIR (buf->st_mode))
347      {
348        errno = ENOTDIR;
349        ret = -1;
350      }
351    if (malloca_rname != NULL)
352      {
353        int saved_errno = errno;
354        freea (malloca_rname);
355        errno = saved_errno;
356      }
357    return ret;
358  }
359
360 failed:
361  {
362    DWORD error = GetLastError ();
363    #if 0
364    fprintf (stderr, "rpl_stat error 0x%x\n", (unsigned int) error);
365    #endif
366
367    if (malloca_rname != NULL)
368      freea (malloca_rname);
369
370    switch (error)
371      {
372      /* Some of these errors probably cannot happen with the specific flags
373         that we pass to CreateFile.  But who knows...  */
374      case ERROR_FILE_NOT_FOUND: /* The last component of rname does not exist.  */
375      case ERROR_PATH_NOT_FOUND: /* Some directory component in rname does not exist.  */
376      case ERROR_BAD_PATHNAME:   /* rname is such as '\\server'.  */
377      case ERROR_BAD_NET_NAME:   /* rname is such as '\\server\nonexistentshare'.  */
378      case ERROR_INVALID_NAME:   /* rname contains wildcards, misplaced colon, etc.  */
379      case ERROR_DIRECTORY:
380        errno = ENOENT;
381        break;
382
383      case ERROR_ACCESS_DENIED:  /* rname is such as 'C:\System Volume Information\foo'.  */
384      case ERROR_SHARING_VIOLATION: /* rname is such as 'C:\pagefile.sys' (second approach only).  */
385                                    /* XXX map to EACCES or EPERM? */
386        errno = EACCES;
387        break;
388
389      case ERROR_OUTOFMEMORY:
390        errno = ENOMEM;
391        break;
392
393      case ERROR_WRITE_PROTECT:
394        errno = EROFS;
395        break;
396
397      case ERROR_WRITE_FAULT:
398      case ERROR_READ_FAULT:
399      case ERROR_GEN_FAILURE:
400        errno = EIO;
401        break;
402
403      case ERROR_BUFFER_OVERFLOW:
404      case ERROR_FILENAME_EXCED_RANGE:
405        errno = ENAMETOOLONG;
406        break;
407
408      case ERROR_DELETE_PENDING: /* XXX map to EACCES or EPERM? */
409        errno = EPERM;
410        break;
411
412      default:
413        errno = EINVAL;
414        break;
415      }
416
417    return -1;
418  }
419#else
420  int result = orig_stat (name, buf);
421  if (result == 0)
422    {
423# if REPLACE_FUNC_STAT_FILE
424      /* Solaris 9 mistakenly succeeds when given a non-directory with a
425         trailing slash.  */
426      if (!S_ISDIR (buf->st_mode))
427        {
428          size_t len = strlen (name);
429          if (ISSLASH (name[len - 1]))
430            {
431              errno = ENOTDIR;
432              return -1;
433            }
434        }
435# endif /* REPLACE_FUNC_STAT_FILE */
436      result = stat_time_normalize (result, buf);
437    }
438  return result;
439#endif
440}
441