X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Futimens.c;h=5603600bf911bd20b5e73b6620db58172a5304bc;hb=ec60d8959e16a743f09704c397931f2621f511ae;hp=9119bc430ec39cdd69b121087fb27a62a8b2ccd1;hpb=aba351689b1b5ce068b76d112c1f4929ac26ab9c;p=gnulib.git

diff --git a/lib/utimens.c b/lib/utimens.c
index 9119bc430..5603600bf 100644
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -49,6 +49,25 @@ struct utimbuf
 };
 #endif
 
+/* Avoid recursion with rpl_futimens or rpl_utimensat.  */
+#undef futimens
+#undef utimensat
+
+#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.
+   There are some Linux kernel versions where a flag of 0 passes, but
+   not AT_SYMLINK_NOFOLLOW.  0 = unknown, 1 = yes, -1 = no.  */
+static int utimensat_works_really;
+static int lutimensat_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
+
 /* 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
@@ -179,52 +198,65 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
 #endif
 
   /* POSIX 2008 added two interfaces to set file timestamps with
-     nanosecond resolution.  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
-  if (fd < 0)
+     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 = 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 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)
-        return result;
+# if HAVE_UTIMENSAT
+      if (fd < 0)
+        {
+          int 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
+      {
+        int 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 */
     }
-#endif
-#if HAVE_FUTIMENS
-  {
-    int result = futimens (fd, timespec);
-# ifdef __linux__
-    /* Work around the same bug as above.  */
-    if (0 < result)
-      errno = ENOSYS;
-# endif
-    if (result == 0 || errno != ENOSYS)
-      return result;
-  }
-#endif
+  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 (adjustment_needed)
+  if (adjustment_needed || (REPLACE_FUNC_STAT_FILE && fd < 0))
     {
       struct stat st;
       if (fd < 0 ? stat (file, &st) : fstat (fd, &st))
         return -1;
-      if (update_timespec (&st, &ts))
+      if (ts && update_timespec (&st, &ts))
         return 0;
     }
 
@@ -261,7 +293,7 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
            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
@@ -273,7 +305,8 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
 
     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;
@@ -321,18 +354,21 @@ gl_futimens (int fd, char const *file, struct timespec const timespec[2])
 int
 utimens (char const *file, struct timespec const timespec[2])
 {
-  return gl_futimens (-1, file, timespec);
+  return fdutimens (file, -1, timespec);
 }
 
-/* Set the access and modification time stamps of the symlink FILE to
-   be TIMESPEC[0] and TIMESPEC[1], respectively.  Fail with ENOSYS if
-   the platform does not support changing symlink timestamps.  */
+/* 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;
+  int result;
 
   if (ts)
     {
@@ -349,39 +385,45 @@ lutimens (char const *file, struct timespec const timespec[2])
      worry about bogus return values.  */
 
 #if HAVE_UTIMENSAT
-  {
-    int result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW);
+  if (0 <= lutimensat_works_really)
+    {
+      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;
+      /* 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)
-      return result;
-  }
+      if (result == 0 || errno != ENOSYS)
+        {
+          utimensat_works_really = 1;
+          lutimensat_works_really = 1;
+          return result;
+        }
+    }
+  lutimensat_works_really = -1;
 #endif /* HAVE_UTIMENSAT */
 
   /* 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)
+  if (adjustment_needed || REPLACE_FUNC_STAT_FILE)
     {
-      struct stat st;
       if (lstat (file, &st))
         return -1;
-      if (update_timespec (&st, &ts))
+      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;
@@ -396,12 +438,17 @@ lutimens (char const *file, struct timespec const timespec[2])
     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.  Symlink timestamps can't be changed.  We won't
-     bother changing the timestamps if FILE was not a symlink.  */
+  /* 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 (file, -1, ts);
   errno = ENOSYS;
   return -1;
 }