source: trunk/src/grep/lib/stat.c@ 3603

Last change on this file since 3603 was 3529, checked in by bird, 4 years ago

Imported grep 3.7 from grep-3.7.tar.gz (sha256: c22b0cf2d4f6bbe599c902387e8058990e1eee99aef333a203829e5fd3dbb342), applying minimal auto-props.
  • Property svn:eol-style set to native
File size: 13.5 KB
Line 
1/* Work around platform bugs in stat.
2 Copyright (C) 2009-2021 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}
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