1 /* Work around an fstatat bug on Solaris 9.
2
3 Copyright (C) 2006, 2009-2014 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18 /* Written by Paul Eggert and Jim Meyering. */
19
20 /* If the user's config.h happens to include <sys/stat.h>, let it include only
21 the system's <sys/stat.h> here, so that orig_fstatat doesn't recurse to
22 rpl_fstatat. */
23 #define __need_system_sys_stat_h
24 #include <config.h>
25
26 /* Get the original definition of fstatat. It might be defined as a macro. */
27 #include <sys/types.h>
28 #include <sys/stat.h>
29 #undef __need_system_sys_stat_h
30
31 #if HAVE_FSTATAT
32 static int
orig_fstatat(int fd,char const * filename,struct stat * buf,int flags)33 orig_fstatat (int fd, char const *filename, struct stat *buf, int flags)
34 {
35 return fstatat (fd, filename, buf, flags);
36 }
37 #endif
38
39 /* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
40 eliminates this include because of the preliminary #include <sys/stat.h>
41 above. */
42 #include "sys/stat.h"
43
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <string.h>
47
48 #if HAVE_FSTATAT && HAVE_WORKING_FSTATAT_ZERO_FLAG
49
50 # ifndef LSTAT_FOLLOWS_SLASHED_SYMLINK
51 # define LSTAT_FOLLOWS_SLASHED_SYMLINK 0
52 # endif
53
54 /* fstatat should always follow symbolic links that end in /, but on
55 Solaris 9 it doesn't if AT_SYMLINK_NOFOLLOW is specified.
56 Likewise, trailing slash on a non-directory should be an error.
57 These are the same problems that lstat.c and stat.c address, so
58 solve it in a similar way.
59
60 AIX 7.1 fstatat (AT_FDCWD, ..., 0) always fails, which is a bug.
61 Work around this bug if FSTATAT_AT_FDCWD_0_BROKEN is nonzero. */
62
63 int
rpl_fstatat(int fd,char const * file,struct stat * st,int flag)64 rpl_fstatat (int fd, char const *file, struct stat *st, int flag)
65 {
66 int result = orig_fstatat (fd, file, st, flag);
67 size_t len;
68
69 if (LSTAT_FOLLOWS_SLASHED_SYMLINK || result != 0)
70 return result;
71 len = strlen (file);
72 if (flag & AT_SYMLINK_NOFOLLOW)
73 {
74 /* Fix lstat behavior. */
75 if (file[len - 1] != '/' || S_ISDIR (st->st_mode))
76 return 0;
77 if (!S_ISLNK (st->st_mode))
78 {
79 errno = ENOTDIR;
80 return -1;
81 }
82 result = orig_fstatat (fd, file, st, flag & ~AT_SYMLINK_NOFOLLOW);
83 }
84 /* Fix stat behavior. */
85 if (result == 0 && !S_ISDIR (st->st_mode) && file[len - 1] == '/')
86 {
87 errno = ENOTDIR;
88 return -1;
89 }
90 return result;
91 }
92
93 #else /* ! (HAVE_FSTATAT && HAVE_WORKING_FSTATAT_ZERO_FLAG) */
94
95 /* On mingw, the gnulib <sys/stat.h> defines 'stat' as a function-like
96 macro; but using it in AT_FUNC_F2 causes compilation failure
97 because the preprocessor sees a use of a macro that requires two
98 arguments but is only given one. Hence, we need an inline
99 forwarder to get past the preprocessor. */
100 static int
stat_func(char const * name,struct stat * st)101 stat_func (char const *name, struct stat *st)
102 {
103 return stat (name, st);
104 }
105
106 /* Likewise, if there is no native 'lstat', then the gnulib
107 <sys/stat.h> defined it as stat, which also needs adjustment. */
108 # if !HAVE_LSTAT
109 # undef lstat
110 # define lstat stat_func
111 # endif
112
113 /* Replacement for Solaris' function by the same name.
114 <http://www.google.com/search?q=fstatat+site:docs.sun.com>
115 First, try to simulate it via l?stat ("/proc/self/fd/FD/FILE").
116 Failing that, simulate it via save_cwd/fchdir/(stat|lstat)/restore_cwd.
117 If either the save_cwd or the restore_cwd fails (relatively unlikely),
118 then give a diagnostic and exit nonzero.
119 Otherwise, this function works just like Solaris' fstatat. */
120
121 # define AT_FUNC_NAME fstatat
122 # define AT_FUNC_F1 lstat
123 # define AT_FUNC_F2 stat_func
124 # define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW
125 # define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat *st, int flag
126 # define AT_FUNC_POST_FILE_ARGS , st
127 # include "at-func.c"
128 # undef AT_FUNC_NAME
129 # undef AT_FUNC_F1
130 # undef AT_FUNC_F2
131 # undef AT_FUNC_USE_F1_COND
132 # undef AT_FUNC_POST_FILE_PARAM_DECLS
133 # undef AT_FUNC_POST_FILE_ARGS
134
135 #endif /* !HAVE_FSTATAT */
136