X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=lib%2Futimens.c;h=ece9b07bbb3d4fb5b9889ed1d5a507c6760fe333;hb=20fcfc81ece044b8b0a6768ec6cf47be4e22a2e6;hp=71bc510d86bb57db59203877a55fdd25d45ab694;hpb=800deb09b422a73c1212233a93839a223ff59678;p=debian%2Fgzip
diff --git a/lib/utimens.c b/lib/utimens.c
index 71bc510..ece9b07 100644
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -1,11 +1,10 @@
/* Set file access and modification times.
- Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software
- Foundation, Inc.
+ Copyright (C) 2003-2016 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify it
+ 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
- Free Software Foundation; either version 2, or (at your option) any
+ Free Software Foundation; either version 3 of the License, or any
later version.
This program is distributed in the hope that it will be useful,
@@ -14,8 +13,7 @@
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see . */
/* Written by Paul Eggert. */
@@ -23,13 +21,19 @@
#include
+#define _GL_UTIMENS_INLINE _GL_EXTERN_INLINE
#include "utimens.h"
#include
#include
+#include
+#include
#include
#include
+#include "stat-time.h"
+#include "timespec.h"
+
#if HAVE_UTIME_H
# include
#endif
@@ -44,25 +48,111 @@ struct utimbuf
};
#endif
-/* Some systems don't have ENOSYS. */
-#ifndef ENOSYS
-# ifdef ENOTSUP
-# define ENOSYS ENOTSUP
-# else
-/* Some systems don't have ENOTSUP either. */
-# define ENOSYS EINVAL
-# endif
-#endif
+/* Avoid recursion with rpl_futimens or rpl_utimensat. */
+#undef futimens
+#undef utimensat
-#ifndef __attribute__
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
-# define __attribute__(x)
-# endif
+/* 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
-#ifndef ATTRIBUTE_UNUSED
-# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
-#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 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;
+ if ((timespec[0].tv_nsec != UTIME_NOW
+ && timespec[0].tv_nsec != UTIME_OMIT
+ && ! (0 <= timespec[0].tv_nsec
+ && timespec[0].tv_nsec < TIMESPEC_RESOLUTION))
+ || (timespec[1].tv_nsec != UTIME_NOW
+ && timespec[1].tv_nsec != UTIME_OMIT
+ && ! (0 <= timespec[1].tv_nsec
+ && timespec[1].tv_nsec < TIMESPEC_RESOLUTION)))
+ {
+ errno = EINVAL;
+ 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.
+ 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 + (utime_omit_count == 1);
+}
+
+/* Normalize any UTIME_NOW or UTIME_OMIT values in *TS, using stat
+ buffer STATBUF to obtain the current timestamps of the file. If
+ both times are UTIME_NOW, set *TS to NULL (as this can avoid some
+ permissions issues). If both times are UTIME_OMIT, return true
+ (nothing further beyond the prior collection of STATBUF is
+ necessary); otherwise return false. */
+static bool
+update_timespec (struct stat const *statbuf, struct timespec *ts[2])
+{
+ struct timespec *timespec = *ts;
+ if (timespec[0].tv_nsec == UTIME_OMIT
+ && timespec[1].tv_nsec == UTIME_OMIT)
+ return true;
+ if (timespec[0].tv_nsec == UTIME_NOW
+ && timespec[1].tv_nsec == UTIME_NOW)
+ {
+ *ts = NULL;
+ return false;
+ }
+
+ if (timespec[0].tv_nsec == UTIME_OMIT)
+ timespec[0] = get_stat_atime (statbuf);
+ else if (timespec[0].tv_nsec == UTIME_NOW)
+ gettime (×pec[0]);
+
+ if (timespec[1].tv_nsec == UTIME_OMIT)
+ timespec[1] = get_stat_mtime (statbuf);
+ else if (timespec[1].tv_nsec == UTIME_NOW)
+ gettime (×pec[1]);
+
+ return false;
+}
/* Set the access and modification time stamps of FD (a.k.a. FILE) to be
TIMESPEC[0] and TIMESPEC[1], respectively.
@@ -75,9 +165,31 @@ struct utimbuf
Return 0 on success, -1 (setting errno) on failure. */
int
-futimens (int fd ATTRIBUTE_UNUSED,
- char const *file, struct timespec const timespec[2])
+fdutimens (int fd, char const *file, struct timespec const timespec[2])
{
+ struct timespec adjusted_timespec[2];
+ struct timespec *ts = timespec ? adjusted_timespec : NULL;
+ int adjustment_needed = 0;
+ struct stat st;
+
+ if (ts)
+ {
+ adjusted_timespec[0] = timespec[0];
+ adjusted_timespec[1] = timespec[1];
+ adjustment_needed = validate_timespec (ts);
+ }
+ if (adjustment_needed < 0)
+ return -1;
+
+ /* Require that at least one of FD or FILE are potentially valid, to avoid
+ a Linux bug where futimens (AT_FDCWD, NULL) changes "." rather
+ than failing. */
+ if (fd < 0 && !file)
+ {
+ errno = EBADF;
+ return -1;
+ }
+
/* Some Linux-based NFS clients are buggy, and mishandle time stamps
of files in NFS file systems in some cases. We have no
configure-time test for this, but please see
@@ -95,95 +207,336 @@ futimens (int fd ATTRIBUTE_UNUSED,
fsync (fd);
#endif
- /* There's currently no interface to set file timestamps with
+ /* POSIX 2008 added two interfaces to set file timestamps with
+ nanosecond resolution; newer Linux implements both functions via
+ a single syscall. We provide a fallback for ENOSYS (for example,
+ compiling against Linux 2.6.25 kernel headers and glibc 2.7, but
+ running on Linux 2.6.18 kernel). */
+#if HAVE_UTIMENSAT || HAVE_FUTIMENS
+ if (0 <= utimensat_works_really)
+ {
+ int result;
+# if __linux__ || __sun
+ /* 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.
+
+ The same bug occurs in Solaris 11.1 (Apr 2013).
+
+ FIXME: Simplify this for Linux in 2016 and for Solaris in
+ 2024, 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
+# if HAVE_UTIMENSAT
+ if (fd < 0)
+ {
+ result = utimensat (AT_FDCWD, file, ts, 0);
+# ifdef __linux__
+ /* Work around a kernel bug:
+ http://bugzilla.redhat.com/442352
+ http://bugzilla.redhat.com/449910
+ It appears that utimensat can mistakenly return 280 rather
+ than -1 upon ENOSYS failure.
+ FIXME: remove in 2010 or whenever the offending kernels
+ are no longer in common use. */
+ if (0 < result)
+ errno = ENOSYS;
+# endif /* __linux__ */
+ if (result == 0 || errno != ENOSYS)
+ {
+ utimensat_works_really = 1;
+ return result;
+ }
+ }
+# endif /* HAVE_UTIMENSAT */
+# if HAVE_FUTIMENS
+ if (0 <= fd)
+ {
+ result = futimens (fd, ts);
+# ifdef __linux__
+ /* 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;
+ }
+ }
+# 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
nanosecond resolution, so do the best we can, discarding any
fractional part of the timestamp. */
-#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES
- struct timeval timeval[2];
- struct timeval const *t;
- if (timespec)
+
+ if (adjustment_needed || (REPLACE_FUNC_STAT_FILE && fd < 0))
{
- timeval[0].tv_sec = timespec[0].tv_sec;
- timeval[0].tv_usec = timespec[0].tv_nsec / 1000;
- timeval[1].tv_sec = timespec[1].tv_sec;
- timeval[1].tv_usec = timespec[1].tv_nsec / 1000;
- t = timeval;
+ if (adjustment_needed != 3
+ && (fd < 0 ? stat (file, &st) : fstat (fd, &st)))
+ return -1;
+ if (ts && update_timespec (&st, &ts))
+ return 0;
}
- else
- t = NULL;
+ {
+#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES
+ struct timeval timeval[2];
+ struct timeval *t;
+ if (ts)
+ {
+ timeval[0].tv_sec = ts[0].tv_sec;
+ timeval[0].tv_usec = ts[0].tv_nsec / 1000;
+ timeval[1].tv_sec = ts[1].tv_sec;
+ timeval[1].tv_usec = ts[1].tv_nsec / 1000;
+ t = timeval;
+ }
+ else
+ t = NULL;
- if (fd < 0)
- {
+ if (fd < 0)
+ {
# if HAVE_FUTIMESAT
- return futimesat (AT_FDCWD, file, t);
+ return futimesat (AT_FDCWD, file, t);
# endif
+ }
+ else
+ {
+ /* If futimesat or futimes fails here, don't try to speed things
+ up by returning right away. glibc can incorrectly fail with
+ errno == ENOENT if /proc isn't mounted. Also, Mandrake 10.0
+ in high security mode doesn't allow ordinary users to read
+ /proc/self, so glibc incorrectly fails with errno == EACCES.
+ If errno == EIO, EPERM, or EROFS, it's probably safe to fail
+ right away, but these cases are rare enough that they're not
+ 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 && !FUTIMESAT_NULL_BUG) || HAVE_FUTIMES
+# if HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG
+# undef futimes
+# define futimes(fd, t) futimesat (fd, NULL, t)
+# endif
+ if (futimes (fd, t) == 0)
+ {
+# if __linux__ && __GLIBC__
+ /* Work around a longstanding glibc bug, still present as
+ of 2010-12-27. On older Linux kernels that lack both
+ utimensat and utimes, glibc's futimes rounds instead of
+ truncating when falling back on utime. The same bug
+ occurs in futimesat with a null 2nd arg. */
+ if (t)
+ {
+ bool abig = 500000 <= t[0].tv_usec;
+ bool mbig = 500000 <= t[1].tv_usec;
+ if ((abig | mbig) && fstat (fd, &st) == 0)
+ {
+ /* If these two subtractions overflow, they'll
+ track the overflows inside the buggy glibc. */
+ time_t adiff = st.st_atime - t[0].tv_sec;
+ time_t mdiff = st.st_mtime - t[1].tv_sec;
+
+ struct timeval *tt = NULL;
+ struct timeval truncated_timeval[2];
+ truncated_timeval[0] = t[0];
+ truncated_timeval[1] = t[1];
+ if (abig && adiff == 1 && get_stat_atime_ns (&st) == 0)
+ {
+ tt = truncated_timeval;
+ tt[0].tv_usec = 0;
+ }
+ if (mbig && mdiff == 1 && get_stat_mtime_ns (&st) == 0)
+ {
+ tt = truncated_timeval;
+ tt[1].tv_usec = 0;
+ }
+ if (tt)
+ futimes (fd, tt);
+ }
+ }
+# endif
+
+ return 0;
+ }
+# endif
+ }
+#endif /* HAVE_FUTIMESAT || HAVE_WORKING_UTIMES */
+
+ if (!file)
+ {
+#if ! ((HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG) \
+ || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
+ errno = ENOSYS;
+#endif
+ return -1;
+ }
+
+#if HAVE_WORKING_UTIMES
+ return utimes (file, t);
+#else
+ {
+ struct utimbuf utimbuf;
+ struct utimbuf *ut;
+ if (ts)
+ {
+ utimbuf.actime = ts[0].tv_sec;
+ utimbuf.modtime = ts[1].tv_sec;
+ ut = &utimbuf;
+ }
+ else
+ ut = NULL;
+
+ return utime (file, ut);
}
- else
+#endif /* !HAVE_WORKING_UTIMES */
+ }
+}
+
+/* Set the access and modification time stamps of FILE to be
+ TIMESPEC[0] and TIMESPEC[1], respectively. */
+int
+utimens (char const *file, struct timespec const timespec[2])
+{
+ return fdutimens (-1, file, timespec);
+}
+
+/* Set the access and modification time stamps of FILE to be
+ TIMESPEC[0] and TIMESPEC[1], respectively, without dereferencing
+ symlinks. Fail with ENOSYS if the platform does not support
+ changing symlink timestamps, but FILE was a symlink. */
+int
+lutimens (char const *file, struct timespec const timespec[2])
+{
+ struct timespec adjusted_timespec[2];
+ struct timespec *ts = timespec ? adjusted_timespec : NULL;
+ int adjustment_needed = 0;
+ struct stat st;
+
+ if (ts)
{
- /* If futimesat or futimes fails here, don't try to speed things
- up by returning right away. glibc can incorrectly fail with
- errno == ENOENT if /proc isn't mounted. Also, Mandrake 10.0
- in high security mode doesn't allow ordinary users to read
- /proc/self, so glibc incorrectly fails with errno == EACCES.
- If errno == EIO, EPERM, or EROFS, it's probably safe to fail
- right away, but these cases are rare enough that they're not
- 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 (futimesat (fd, NULL, t) == 0)
- return 0;
-# elif HAVE_FUTIMES
- if (futimes (fd, t) == 0)
- return 0;
-# endif
+ adjusted_timespec[0] = timespec[0];
+ adjusted_timespec[1] = timespec[1];
+ adjustment_needed = validate_timespec (ts);
}
-#endif
+ if (adjustment_needed < 0)
+ return -1;
+
+ /* The Linux kernel did not support symlink timestamps until
+ utimensat, in version 2.6.22, so we don't need to mimic
+ fdutimens' worry about buggy NFS clients. But we do have to
+ worry about bogus return values. */
- if (!file)
+#if HAVE_UTIMENSAT
+ if (0 <= lutimensat_works_really)
{
-#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
- errno = ENOSYS;
-#endif
+ int result;
+# if __linux__ || __sun
+ /* 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.
- /* Prefer EBADF to ENOSYS if both error numbers apply. */
- if (errno == ENOSYS)
- {
- int fd2 = dup (fd);
- int dup_errno = errno;
- if (0 <= fd2)
- close (fd2);
- errno = (fd2 < 0 && dup_errno == EBADF ? EBADF : ENOSYS);
- }
+ The same bug occurs in Solaris 11.1 (Apr 2013).
- return -1;
+ FIXME: Simplify this for Linux in 2016 and for Solaris in
+ 2024, 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
+ result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW);
+# ifdef __linux__
+ /* Work around a kernel bug:
+ http://bugzilla.redhat.com/442352
+ http://bugzilla.redhat.com/449910
+ It appears that utimensat can mistakenly return 280 rather
+ than -1 upon ENOSYS failure.
+ FIXME: remove in 2010 or whenever the offending kernels
+ are no longer in common use. */
+ if (0 < result)
+ errno = ENOSYS;
+# endif
+ if (result == 0 || errno != ENOSYS)
+ {
+ utimensat_works_really = 1;
+ lutimensat_works_really = 1;
+ return result;
+ }
}
+ lutimensat_works_really = -1;
+#endif /* HAVE_UTIMENSAT */
-#if HAVE_WORKING_UTIMES
- return utimes (file, t);
-#else
+ /* The platform lacks an interface to set file timestamps with
+ nanosecond resolution, so do the best we can, discarding any
+ fractional part of the timestamp. */
+
+ if (adjustment_needed || REPLACE_FUNC_STAT_FILE)
+ {
+ if (adjustment_needed != 3 && lstat (file, &st))
+ return -1;
+ if (ts && update_timespec (&st, &ts))
+ return 0;
+ }
+
+ /* 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 utimbuf utimbuf;
- struct utimbuf const *ut;
- if (timespec)
+ struct timeval timeval[2];
+ struct timeval *t;
+ int result;
+ if (ts)
{
- utimbuf.actime = timespec[0].tv_sec;
- utimbuf.modtime = timespec[1].tv_sec;
- ut = &utimbuf;
+ timeval[0].tv_sec = ts[0].tv_sec;
+ timeval[0].tv_usec = ts[0].tv_nsec / 1000;
+ timeval[1].tv_sec = ts[1].tv_sec;
+ timeval[1].tv_usec = ts[1].tv_nsec / 1000;
+ t = timeval;
}
else
- ut = NULL;
+ t = NULL;
- return utime (file, ut);
+ result = lutimes (file, t);
+ if (result == 0 || errno != ENOSYS)
+ return result;
}
-#endif
-}
+#endif /* HAVE_LUTIMES && !HAVE_UTIMENSAT */
-/* Set the access and modification time stamps of FILE to be
- TIMESPEC[0] and TIMESPEC[1], respectively. */
-int
-utimens (char const *file, struct timespec const timespec[2])
-{
- return futimens (-1, file, timespec);
+ /* Out of luck for symlinks, but we still handle regular files. */
+ if (!(adjustment_needed || REPLACE_FUNC_STAT_FILE) && lstat (file, &st))
+ return -1;
+ if (!S_ISLNK (st.st_mode))
+ return fdutimens (-1, file, ts);
+ errno = ENOSYS;
+ return -1;
}