Re: no feedback on snapshot? coreutils-7.5 coming soon

[Pádraig Brady]

Pádraig Brady wrote:
> Jim Meyering wrote:
>> AFAIK, I am the only one who has built the latest snapshot:
>>
>>     http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/17604
>>
>> Though it's been only two days.
>>
>> Unless I hear of new bug reports or portability problems soon,
>> expect coreutils-7.5 to be released in the next few days.
> 
> checks pass on Fedora 11 and Ubuntu 7.10
> 2 failures on Fedora Core 5 due to copy::utimensat_if_possible() failing with:
> 
> $ (cd tests && make check TESTS=cp/abuse VERBOSE=yes)
> cp: preserving times for `c/1': No such file or directory
> 
> $ (cd tests && make check TESTS=mv/part-symlink VERBOSE=yes)
> mv: preserving times for `loc_reg': Too many levels of symbolic links

These highlighted a couple of issue I think on systems without utimensat().

1. The symlink _target_ gets its time updated
2. If 1 fails then the process returns a failure

I've fixed both in the attached patch hopefully
by only doing the explicit utimensat() on symlinks,
and only giving a warning if errno==ENOTSUP.
Note it might be cleaner to add a O_NOFOLLOW flag to
utimens() in gnulib, but that would be more invasive.

I also tweaked the tests not to fail on systems
without utimensat().

cheers,
Pádraig.

>From d337e3c7c081e1262ea13fbe239938c451b0a93d Mon Sep 17 00:00:00 2001
From: =?utf-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Thu, 13 Aug 2009 10:39:10 +0100
Subject: [PATCH] cp, mv: fix issues with preserving timestamps of copied 
symlinks

* src/copy.c (copy_internal): On systems without utimensat() don't
revert to utimens as that will update the timestamp of the symlink
target.  Also just warn on systems without utimensat(), don't fail.
* tests/cp/abuse: To work around a failure on systems without
utimensat(), use cp -dR rather than cp -a.
* tests/mv/part-symlink: Skip the test on systems without
utimensat(), as mv -b will warn there, messing up the test.
---
 src/copy.c            |   20 +++++++++++---------
 tests/cp/abuse        |    2 +-
 tests/mv/part-symlink |    6 ++++++
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/copy.c b/src/copy.c
index bed90c4..068eef7 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -118,18 +118,17 @@ static bool owner_failure_ok (struct cp_options const *x);
 static char const *top_level_src_name;
 static char const *top_level_dst_name;
 
-/* Wrap utimensat-with-AT_FDCWD and utimens, to keep these
-   cpp directives out of the main code.  */
+/* Try to update the timestamp of a symlink.
+   We don't revert to utimens as that will follow the link.  */
 static inline int
-utimensat_if_possible (char const *file, struct timespec const *timespec)
+utimens_symlink (char const *file, struct timespec const *timespec)
 {
-  return
 #if HAVE_UTIMENSAT
-    utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW)
+  return utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW);
 #else
-    utimens (file, timespec)
+  errno = ENOTSUP;
+  return -1;
 #endif
-    ;
 }
 
 /* Perform the O(1) btrfs clone operation, if possible.
@@ -2117,10 +2116,13 @@ copy_internal (char const *src_name, char const 
*dst_name,
       timespec[0] = get_stat_atime (&src_sb);
       timespec[1] = get_stat_mtime (&src_sb);
 
-      if (utimensat_if_possible (dst_name, timespec) != 0)
+      if ((dest_is_symlink
+          ? utimens_symlink (dst_name, timespec)
+          : utimens (dst_name, timespec))
+         != 0)
        {
          error (0, errno, _("preserving times for %s"), quote (dst_name));
-         if (x->require_preserve)
+         if (x->require_preserve && ! (dest_is_symlink && errno == ENOTSUP))
            return false;
        }
     }
diff --git a/tests/cp/abuse b/tests/cp/abuse
index 285c531..e9086b8 100755
--- a/tests/cp/abuse
+++ b/tests/cp/abuse
@@ -37,7 +37,7 @@ for i in dangling-dest existing-dest; do
   test $i = existing-dest && echo i > t
   test $i = dangling-dest && rm -f t
 
-  cp -a a/1 b/1 c 2> out && fail=1
+  cp -dR a/1 b/1 c 2> out && fail=1
 
   compare out exp || fail=1
 
diff --git a/tests/mv/part-symlink b/tests/mv/part-symlink
index 78da70a..576bb40 100755
--- a/tests/mv/part-symlink
+++ b/tests/mv/part-symlink
@@ -27,6 +27,12 @@ fi
 cleanup_() { rm -rf "$other_partition_tmpdir"; }
 . "$abs_srcdir/other-fs-tmpdir"
 
+# without utimensat() mv -b will give warnings about not
+# being able to preserve the timestamps of symlinks.
+# So just skip the test on older systems like this.
+grep '^#define HAVE_UTIMENSAT' "$CONFIG_HEADER" > /dev/null ||
+  skip_test_ 'system will warn about preserving timestamps of symlinks'
+
 pwd_tmp=`pwd`
 
 # Unset CDPATH.  Otherwise, output from the `cd dir' command
-- 
1.6.2.5