1/* Set file access and modification times.
2
3   Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software
4   Foundation, Inc.
5
6   This program is free software; you can redistribute it and/or modify it
7   under the terms of the GNU General Public License as published by the
8   Free Software Foundation; either version 2, or (at your option) any
9   later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software Foundation,
18   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
19
20/* Written by Paul Eggert.  */
21
22/* derived from a function in touch.c */
23
24#include <config.h>
25
26#include "utimens.h"
27
28#include <errno.h>
29#include <fcntl.h>
30#include <sys/time.h>
31#include <unistd.h>
32
33#if HAVE_UTIME_H
34# include <utime.h>
35#endif
36
37/* Some systems (even some that do have <utime.h>) don't declare this
38   structure anywhere.  */
39#ifndef HAVE_STRUCT_UTIMBUF
40struct utimbuf
41{
42  long actime;
43  long modtime;
44};
45#endif
46
47/* Some systems don't have ENOSYS.  */
48#ifndef ENOSYS
49# ifdef ENOTSUP
50#  define ENOSYS ENOTSUP
51# else
52/* Some systems don't have ENOTSUP either.  */
53#  define ENOSYS EINVAL
54# endif
55#endif
56
57#ifndef __attribute__
58# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
59#  define __attribute__(x)
60# endif
61#endif
62
63#ifndef ATTRIBUTE_UNUSED
64# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
65#endif
66
67/* Set the access and modification time stamps of FD (a.k.a. FILE) to be
68   TIMESPEC[0] and TIMESPEC[1], respectively.
69   FD must be either negative -- in which case it is ignored --
70   or a file descriptor that is open on FILE.
71   If FD is nonnegative, then FILE can be NULL, which means
72   use just futimes (or equivalent) instead of utimes (or equivalent),
73   and fail if on an old system without futimes (or equivalent).
74   If TIMESPEC is null, set the time stamps to the current time.
75   Return 0 on success, -1 (setting errno) on failure.  */
76
77int
78gl_futimens (int fd ATTRIBUTE_UNUSED,
79	     char const *file, struct timespec const timespec[2])
80{
81  /* Some Linux-based NFS clients are buggy, and mishandle time stamps
82     of files in NFS file systems in some cases.  We have no
83     configure-time test for this, but please see
84     <http://bugs.gentoo.org/show_bug.cgi?id=132673> for references to
85     some of the problems with Linux 2.6.16.  If this affects you,
86     compile with -DHAVE_BUGGY_NFS_TIME_STAMPS; this is reported to
87     help in some cases, albeit at a cost in performance.  But you
88     really should upgrade your kernel to a fixed version, since the
89     problem affects many applications.  */
90
91#if HAVE_BUGGY_NFS_TIME_STAMPS
92  if (fd < 0)
93    sync ();
94  else
95    fsync (fd);
96#endif
97
98  /* There's currently no interface to set file timestamps with
99     nanosecond resolution, so do the best we can, discarding any
100     fractional part of the timestamp.  */
101#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES
102  struct timeval timeval[2];
103  struct timeval const *t;
104  if (timespec)
105    {
106      timeval[0].tv_sec = timespec[0].tv_sec;
107      timeval[0].tv_usec = timespec[0].tv_nsec / 1000;
108      timeval[1].tv_sec = timespec[1].tv_sec;
109      timeval[1].tv_usec = timespec[1].tv_nsec / 1000;
110      t = timeval;
111    }
112  else
113    t = NULL;
114
115
116  if (fd < 0)
117    {
118# if HAVE_FUTIMESAT
119      return futimesat (AT_FDCWD, file, t);
120# endif
121    }
122  else
123    {
124      /* If futimesat or futimes fails here, don't try to speed things
125	 up by returning right away.  glibc can incorrectly fail with
126	 errno == ENOENT if /proc isn't mounted.  Also, Mandrake 10.0
127	 in high security mode doesn't allow ordinary users to read
128	 /proc/self, so glibc incorrectly fails with errno == EACCES.
129	 If errno == EIO, EPERM, or EROFS, it's probably safe to fail
130	 right away, but these cases are rare enough that they're not
131	 worth optimizing, and who knows what other messed-up systems
132	 are out there?  So play it safe and fall back on the code
133	 below.  */
134# if HAVE_FUTIMESAT
135      if (futimesat (fd, NULL, t) == 0)
136	return 0;
137# elif HAVE_FUTIMES
138      if (futimes (fd, t) == 0)
139	return 0;
140# endif
141    }
142#endif
143
144  if (!file)
145    {
146#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
147      errno = ENOSYS;
148#endif
149
150      /* Prefer EBADF to ENOSYS if both error numbers apply.  */
151      if (errno == ENOSYS)
152	{
153	  int fd2 = dup (fd);
154	  int dup_errno = errno;
155	  if (0 <= fd2)
156	    close (fd2);
157	  errno = (fd2 < 0 && dup_errno == EBADF ? EBADF : ENOSYS);
158	}
159
160      return -1;
161    }
162
163#if HAVE_WORKING_UTIMES
164  return utimes (file, t);
165#else
166  {
167    struct utimbuf utimbuf;
168    struct utimbuf const *ut;
169    if (timespec)
170      {
171	utimbuf.actime = timespec[0].tv_sec;
172	utimbuf.modtime = timespec[1].tv_sec;
173	ut = &utimbuf;
174      }
175    else
176      ut = NULL;
177
178    return utime (file, ut);
179  }
180#endif
181}
182
183/* Set the access and modification time stamps of FILE to be
184   TIMESPEC[0] and TIMESPEC[1], respectively.  */
185int
186utimens (char const *file, struct timespec const timespec[2])
187{
188  return gl_futimens (-1, file, timespec);
189}
190