coreutils-8.25HEADcoreutils-8.25master

1 files changed, 444 insertions, 91 deletions

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 <http://www.gnu.org/licenses/>.  */
 
 /* Written by Paul Eggert.  */
 
@@ -23,13 +21,19 @@
 
 #include <config.h>
 
+#define _GL_UTIMENS_INLINE _GL_EXTERN_INLINE
 #include "utimens.h"
 
 #include <errno.h>
 #include <fcntl.h>
+#include <stdbool.h>
+#include <sys/stat.h>
 #include <sys/time.h>
 #include <unistd.h>
 
+#include "stat-time.h"
+#include "timespec.h"
+
 #if HAVE_UTIME_H
 # include <utime.h>
 #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 (&timespec[0]);
+
+  if (timespec[1].tv_nsec == UTIME_OMIT)
+    timespec[1] = get_stat_mtime (statbuf);
+  else if (timespec[1].tv_nsec == UTIME_NOW)
+    gettime (&timespec[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;
 }