stat.c

Last change on this file was 3529, checked in by bird, 3 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
36	static int
37	orig_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. */
79	static BOOL
80	is_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
111	int
112	rpl_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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source: kBuild/trunk/src/grep/lib/stat.c

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