/* Set file access and modification times.
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free
- Software Foundation, Inc.
+ Copyright (C) 2003-2010 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
#undef futimens
#undef utimensat
-#if HAVE_UTIMENSAT || HAVE_FUTIMENS
-/* Cache variable for whether syscall works; used to avoid calling the
- syscall if we know it will just fail with ENOSYS. 0 = unknown, 1 =
- yes, -1 = no. */
-static int utimensat_works_really;
-#endif /* HAVE_UTIMENSAT || HAVE_UTIMENSAT */
-
/* Solaris 9 mistakenly succeeds when given a non-directory with a
trailing slash. Force the use of rpl_stat for a fix. */
#ifndef REPLACE_FUNC_STAT_FILE
# define REPLACE_FUNC_STAT_FILE 0
#endif
+#if HAVE_UTIMENSAT || HAVE_FUTIMENS
+/* Cache variables for whether the utimensat syscall works; used to
+ avoid calling the syscall if we know it will just fail with ENOSYS,
+ and to avoid unnecessary work in massaging timestamps if the
+ syscall will work. Multiple variables are needed, to distinguish
+ between the following scenarios on Linux:
+ utimensat doesn't exist, or is in glibc but kernel 2.6.18 fails with ENOSYS
+ kernel 2.6.22 and earlier rejects AT_SYMLINK_NOFOLLOW
+ kernel 2.6.25 and earlier reject UTIME_NOW/UTIME_OMIT with non-zero tv_sec
+ kernel 2.6.32 used with xfs or ntfs-3g fail to honor UTIME_OMIT
+ utimensat completely works
+ For each cache variable: 0 = unknown, 1 = yes, -1 = no. */
+static int utimensat_works_really;
+static int lutimensat_works_really;
+#endif /* HAVE_UTIMENSAT || HAVE_FUTIMENS */
+
/* Validate the requested timestamps. Return 0 if the resulting
timespec can be used for utimensat (after possibly modifying it to
- work around bugs in utimensat). Return 1 if the timespec needs
- further adjustment based on stat results for utimes or other less
- powerful interfaces. Return -1, with errno set to EINVAL, if
+ work around bugs in utimensat). Return a positive value if the
+ timespec needs further adjustment based on stat results: 1 if any
+ adjustment is needed for utimes, and 2 if any adjustment is needed
+ for Linux utimensat. Return -1, with errno set to EINVAL, if
timespec is out of range. */
static int
validate_timespec (struct timespec timespec[2])
{
int result = 0;
+ int utime_omit_count = 0;
assert (timespec);
if ((timespec[0].tv_nsec != UTIME_NOW
&& timespec[0].tv_nsec != UTIME_OMIT
return -1;
}
/* Work around Linux kernel 2.6.25 bug, where utimensat fails with
- EINVAL if tv_sec is not 0 when using the flag values of
- tv_nsec. */
+ EINVAL if tv_sec is not 0 when using the flag values of tv_nsec.
+ Flag a Linux kernel 2.6.32 bug, where an mtime of UTIME_OMIT
+ fails to bump ctime. */
if (timespec[0].tv_nsec == UTIME_NOW
|| timespec[0].tv_nsec == UTIME_OMIT)
{
timespec[0].tv_sec = 0;
result = 1;
+ if (timespec[0].tv_nsec == UTIME_OMIT)
+ utime_omit_count++;
}
if (timespec[1].tv_nsec == UTIME_NOW
|| timespec[1].tv_nsec == UTIME_OMIT)
{
timespec[1].tv_sec = 0;
result = 1;
+ if (timespec[1].tv_nsec == UTIME_OMIT)
+ utime_omit_count++;
}
- return result;
+ return result + (utime_omit_count == 1);
}
/* Normalize any UTIME_NOW or UTIME_OMIT values in *TS, using stat
struct timespec adjusted_timespec[2];
struct timespec *ts = timespec ? adjusted_timespec : NULL;
int adjustment_needed = 0;
+ struct stat st;
if (ts)
{
#if HAVE_UTIMENSAT || HAVE_FUTIMENS
if (0 <= utimensat_works_really)
{
+ int result;
+# if __linux__
+ /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
+ systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
+ but work if both times are either explicitly specified or
+ UTIME_NOW. Work around it with a preparatory [f]stat prior
+ to calling futimens/utimensat; fortunately, there is not much
+ timing impact due to the extra syscall even on file systems
+ where UTIME_OMIT would have worked. FIXME: Simplify this in
+ 2012, when file system bugs are no longer common. */
+ if (adjustment_needed == 2)
+ {
+ if (fd < 0 ? stat (file, &st) : fstat (fd, &st))
+ return -1;
+ if (ts[0].tv_nsec == UTIME_OMIT)
+ ts[0] = get_stat_atime (&st);
+ else if (ts[1].tv_nsec == UTIME_OMIT)
+ ts[1] = get_stat_mtime (&st);
+ /* Note that st is good, in case utimensat gives ENOSYS. */
+ adjustment_needed++;
+ }
+# endif /* __linux__ */
# if HAVE_UTIMENSAT
if (fd < 0)
{
- int result = utimensat (AT_FDCWD, file, ts, 0);
+ result = utimensat (AT_FDCWD, file, ts, 0);
# ifdef __linux__
/* Work around a kernel bug:
http://bugzilla.redhat.com/442352
}
# endif /* HAVE_UTIMENSAT */
# if HAVE_FUTIMENS
- {
- int result = futimens (fd, timespec);
+ if (0 <= fd)
+ {
+ result = futimens (fd, ts);
# ifdef __linux__
- /* Work around the same bug as above. */
- if (0 < result)
- errno = ENOSYS;
+ /* Work around the same bug as above. */
+ if (0 < result)
+ errno = ENOSYS;
# endif /* __linux__ */
- if (result == 0 || errno != ENOSYS)
- {
- utimensat_works_really = 1;
- return result;
- }
- }
+ if (result == 0 || errno != ENOSYS)
+ {
+ utimensat_works_really = 1;
+ return result;
+ }
+ }
# endif /* HAVE_FUTIMENS */
}
utimensat_works_really = -1;
+ lutimensat_works_really = -1;
#endif /* HAVE_UTIMENSAT || HAVE_FUTIMENS */
/* The platform lacks an interface to set file timestamps with
if (adjustment_needed || (REPLACE_FUNC_STAT_FILE && fd < 0))
{
- struct stat st;
- if (fd < 0 ? stat (file, &st) : fstat (fd, &st))
+ if (adjustment_needed != 3
+ && (fd < 0 ? stat (file, &st) : fstat (fd, &st)))
return -1;
if (ts && update_timespec (&st, &ts))
return 0;
worth optimizing, and who knows what other messed-up systems
are out there? So play it safe and fall back on the code
below. */
-# if HAVE_FUTIMESAT
+# if HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG
if (futimesat (fd, NULL, t) == 0)
return 0;
# elif HAVE_FUTIMES
if (!file)
{
-#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
+#if ! ((HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG) \
+ || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
errno = ENOSYS;
#endif
return -1;
worry about bogus return values. */
#if HAVE_UTIMENSAT
- if (0 <= utimensat_works_really)
+ if (0 <= lutimensat_works_really)
{
- int result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW);
+ int result;
+# if __linux__
+ /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
+ systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
+ but work if both times are either explicitly specified or
+ UTIME_NOW. Work around it with a preparatory lstat prior to
+ calling utimensat; fortunately, there is not much timing
+ impact due to the extra syscall even on file systems where
+ UTIME_OMIT would have worked. FIXME: Simplify this in 2012,
+ when file system bugs are no longer common. */
+ if (adjustment_needed == 2)
+ {
+ if (lstat (file, &st))
+ return -1;
+ if (ts[0].tv_nsec == UTIME_OMIT)
+ ts[0] = get_stat_atime (&st);
+ else if (ts[1].tv_nsec == UTIME_OMIT)
+ ts[1] = get_stat_mtime (&st);
+ /* Note that st is good, in case utimensat gives ENOSYS. */
+ adjustment_needed++;
+ }
+# endif /* __linux__ */
+ result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW);
# ifdef __linux__
/* Work around a kernel bug:
http://bugzilla.redhat.com/442352
if (result == 0 || errno != ENOSYS)
{
utimensat_works_really = 1;
+ lutimensat_works_really = 1;
return result;
}
}
- utimensat_works_really = -1;
+ lutimensat_works_really = -1;
#endif /* HAVE_UTIMENSAT */
/* The platform lacks an interface to set file timestamps with
if (adjustment_needed || REPLACE_FUNC_STAT_FILE)
{
- if (lstat (file, &st))
+ if (adjustment_needed != 3 && lstat (file, &st))
return -1;
if (ts && update_timespec (&st, &ts))
return 0;
}
-#if HAVE_LUTIMES
+ /* On Linux, lutimes is a thin wrapper around utimensat, so there is
+ no point trying lutimes if utimensat failed with ENOSYS. */
+#if HAVE_LUTIMES && !HAVE_UTIMENSAT
{
struct timeval timeval[2];
struct timeval const *t;
+ int result;
if (ts)
{
timeval[0].tv_sec = ts[0].tv_sec;
else
t = NULL;
- return lutimes (file, t);
+ result = lutimes (file, t);
+ if (result == 0 || errno != ENOSYS)
+ return result;
}
-#endif /* HAVE_LUTIMES */
+#endif /* HAVE_LUTIMES && !HAVE_UTIMENSAT */
/* Out of luck for symlinks, but we still handle regular files. */
if (!(adjustment_needed || REPLACE_FUNC_STAT_FILE) && lstat (file, &st))
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