From b566edc2489a889d97416d2390be7796aa8cdbeb Mon Sep 17 00:00:00 2001

From: Eric Blake <ebb9@byu.net>

Date: Mon, 2 Jun 2008 15:08:14 -0600

Subject: [PATCH] Provide futimens/utimensat fallbacks for older kernels.

* lib/utimens.c (gl_futimens) [HAVE_UTIMENSAT, HAVE_FUTIMENS]:

Provide runtime fallback if kernel lacks support.

Reported by Mike Frysinger.

Signed-off-by: Eric Blake <ebb9@byu.net>

---

 lib/utimens.c |   43 ++++++++++++++++++++++++++-----------------

 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/lib/utimens.c b/lib/utimens.c

index 25bc965..134310b 100644

--- a/lib/utimens.c

+++ b/lib/utimens.c

@@ -96,20 +96,30 @@ gl_futimens (int fd ATTRIBUTE_UNUSED,

 #endif

   /* POSIX 200x added two interfaces to set file timestamps with

-     nanosecond resolution.  */

+     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)

-    return utimensat (AT_FDCWD, file, timespec, 0);

+    {

+      int result = utimensat (AT_FDCWD, file, timespec, 0);

+      if (result == 0 || errno != ENOSYS)

+        return result;

+    }

 #endif

 #if HAVE_FUTIMENS

-  return futimens (fd, timespec);

-#else

+  {

+    int result = futimens (fd, timespec);

+    if (result == 0 || errno != ENOSYS)

+      return result;

+  }

+#endif

   /* 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

+#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES

     struct timeval timeval[2];

     struct timeval const *t;

     if (timespec)

@@ -125,9 +135,9 @@ gl_futimens (int fd ATTRIBUTE_UNUSED,

     if (fd < 0)

       {

-#  if HAVE_FUTIMESAT

+# if HAVE_FUTIMESAT

 	return futimesat (AT_FDCWD, file, t);

-#  endif

+# endif

       }

     else

       {

@@ -141,21 +151,21 @@ gl_futimens (int fd ATTRIBUTE_UNUSED,

 	   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

 	if (futimesat (fd, NULL, t) == 0)

 	  return 0;

-#  elif HAVE_FUTIMES

+# elif HAVE_FUTIMES

 	if (futimes (fd, t) == 0)

 	  return 0;

-#  endif

+# endif

       }

-# endif /* HAVE_FUTIMESAT || HAVE_WORKING_UTIMES */

+#endif /* HAVE_FUTIMESAT || HAVE_WORKING_UTIMES */

     if (!file)

       {

-# if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))

+#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))

 	errno = ENOSYS;

-# endif

+#endif

 	/* Prefer EBADF to ENOSYS if both error numbers apply.  */

 	if (errno == ENOSYS)

@@ -170,9 +180,9 @@ gl_futimens (int fd ATTRIBUTE_UNUSED,

 	return -1;

       }

-# if HAVE_WORKING_UTIMES

+#if HAVE_WORKING_UTIMES

     return utimes (file, t);

-# else

+#else

     {

       struct utimbuf utimbuf;

       struct utimbuf const *ut;

@@ -187,9 +197,8 @@ gl_futimens (int fd ATTRIBUTE_UNUSED,

       return utime (file, ut);

     }

-# endif /* !HAVE_WORKING_UTIMES */

+#endif /* !HAVE_WORKING_UTIMES */

   }

-#endif /* !HAVE_FUTIMENS */

 }

 /* Set the access and modification time stamps of FILE to be

-- 

1.5.5.1