Andreas Schwab <schwab <at> suse.de> writes:
>
> Mike Frysinger <vapier <at> gentoo.org> writes:
>
> > also after reading it, i dont think gnu/stubs.h would help in this
particular
> > case. gnulib would need a runtime test to detect that utimensat() is
> > actually not available.
>
> That should be pretty easy, just fall through to the fallback code when
> errno == ENOSYS.
>
> Andreas.
>
Does this solve your problem? Unfortunately, it bloats code in the case where
utimensat works just fine in the kernel.
>From b566edc2489a889d97416d2390be7796aa8cdbeb Mon Sep 17 00:00:00 2001
From: Eric Blake <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
---
ChangeLog | 7 +++++++
lib/utimens.c | 43 ++++++++++++++++++++++++++-----------------
2 files changed, 33 insertions(+), 17 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 84346f7..c552fd5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2008-06-02 Eric Blake <[EMAIL PROTECTED]>
+
+ Provide fallback for older kernels.
+ * lib/utimens.c (gl_futimens) [HAVE_UTIMENSAT, HAVE_FUTIMENS]:
+ Provide runtime fallback if kernel lacks support.
+ Reported by Mike Frysinger.
+
2008-06-01 Bruno Haible <[EMAIL PROTECTED]>
* lib/copy-acl.c (qcopy_acl): New function, extracted from copy_acl.
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
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