1 /* Set the access and modification time of a file relative to directory fd.
2 Copyright (C) 2009-2013 Free Software Foundation, Inc.
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.
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.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* written by Eric Blake */
26 #include "stat-time.h"
34 /* If we have a native utimensat, but are compiling this file, then
35 utimensat was defined to rpl_utimensat by our replacement
36 sys/stat.h. We assume the native version might fail with ENOSYS,
37 or succeed without properly affecting ctime (as is the case when
38 using newer glibc but older Linux kernel). In this scenario,
39 rpl_utimensat checks whether the native version is usable, and
40 local_utimensat provides the fallback manipulation. */
42 static int local_utimensat (int, char const *, struct timespec const[2], int);
43 # define AT_FUNC_NAME local_utimensat
45 /* Like utimensat, but work around native bugs. */
48 rpl_utimensat (int fd, char const *file, struct timespec const times[2],
52 struct timespec ts[2];
55 /* See comments in utimens.c for details. */
56 static int utimensat_works_really; /* 0 = unknown, 1 = yes, -1 = no. */
57 if (0 <= utimensat_works_really)
62 /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
63 systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
64 but work if both times are either explicitly specified or
65 UTIME_NOW. Work around it with a preparatory [l]stat prior
66 to calling utimensat; fortunately, there is not much timing
67 impact due to the extra syscall even on file systems where
68 UTIME_OMIT would have worked. FIXME: Simplify this in 2012,
69 when file system bugs are no longer common. */
70 if (times && (times[0].tv_nsec == UTIME_OMIT
71 || times[1].tv_nsec == UTIME_OMIT))
73 if (fstatat (fd, file, &st, flag))
75 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT)
77 if (times[0].tv_nsec == UTIME_OMIT)
78 ts[0] = get_stat_atime (&st);
81 if (times[1].tv_nsec == UTIME_OMIT)
82 ts[1] = get_stat_mtime (&st);
88 /* Linux kernel 2.6.22.19 on hppa does not reject invalid tv_nsec
91 && ((times[0].tv_nsec != UTIME_NOW
92 && (times[0].tv_nsec < 0
93 || times[0].tv_nsec >= 1000000000))
94 || (times[1].tv_nsec != UTIME_NOW
95 && (times[1].tv_nsec < 0
96 || times[1].tv_nsec >= 1000000000))))
102 # endif /* __linux__ */
103 result = utimensat (fd, file, times, flag);
104 /* Linux kernel 2.6.25 has a bug where it returns EINVAL for
105 UTIME_NOW or UTIME_OMIT with non-zero tv_sec, which
106 local_utimensat works around. Meanwhile, EINVAL for a bad
107 flag is indeterminate whether the native utimensat works, but
108 local_utimensat will also reject it. */
109 if (result == -1 && errno == EINVAL && (flag & ~AT_SYMLINK_NOFOLLOW))
111 if (result == 0 || (errno != ENOSYS && errno != EINVAL))
113 utimensat_works_really = 1;
117 /* No point in trying openat/futimens, since on Linux, futimens is
118 implemented with the same syscall as utimensat. Only avoid the
119 native utimensat due to an ENOSYS failure; an EINVAL error was
120 data-dependent, and the next caller may pass valid data. */
121 if (0 <= utimensat_works_really && errno == ENOSYS)
122 utimensat_works_really = -1;
123 return local_utimensat (fd, file, times, flag);
126 #else /* !HAVE_UTIMENSAT */
128 # define AT_FUNC_NAME utimensat
130 #endif /* !HAVE_UTIMENSAT */
132 /* Set the access and modification time stamps of FILE to be
133 TIMESPEC[0] and TIMESPEC[1], respectively; relative to directory
134 FD. If flag is AT_SYMLINK_NOFOLLOW, change the times of a symlink,
135 or fail with ENOSYS if not possible. If TIMESPEC is null, set the
136 time stamps to the current time. If possible, do it without
137 changing the working directory. Otherwise, resort to using
138 save_cwd/fchdir, then utimens/restore_cwd. If either the save_cwd
139 or the restore_cwd fails, then give a diagnostic and exit nonzero.
140 Return 0 on success, -1 (setting errno) on failure. */
142 /* AT_FUNC_NAME is now utimensat or local_utimensat. */
143 #define AT_FUNC_F1 lutimens
144 #define AT_FUNC_F2 utimens
145 #define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW
146 #define AT_FUNC_POST_FILE_PARAM_DECLS , struct timespec const ts[2], int flag
147 #define AT_FUNC_POST_FILE_ARGS , ts
152 #undef AT_FUNC_USE_F1_COND
153 #undef AT_FUNC_POST_FILE_PARAM_DECLS
154 #undef AT_FUNC_POST_FILE_ARGS