Re: [PATCH] cp: ignore obscure failure to preserve symlink time stamps,

[Jim Meyering]

Pádraig Brady wrote:

> Jim Meyering wrote:
>> The "preserve symlink time stamps" feature in coreutils-7.5
>> is causing trouble in Fedora's build system,
>>
>>     http://thread.gmane.org/gmane.linux.redhat.fedora.devel/119834
>>
>> because they use a kernel without utimensat support, yet configured/built
>> coreutils-7.5 in an environment that suggests (via link tests) that the
>> function is available.  Here is the fix I expect to push soon:
>
>> diff --git a/src/copy.c b/src/copy.c
>> index bf9230b..8fc4b68 100644
>> --- a/src/copy.c
>> +++ b/src/copy.c
>> @@ -124,7 +124,13 @@ static inline int
>>  utimens_symlink (char const *file, struct timespec const *timespec)
>>  {
>>  #if HAVE_UTIMENSAT
>> -  return utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW);
>> +  int err = utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW);
>> +  /* When configuring on a system with new headers and libraries, and
>> +     running on one with a kernel that is old enough to lack the syscall,
>> +     utimensat fails with ENOTSUP.  Ignore that.  */
>> +  if (err && errno == ENOSYS)
>> +    err = 0;
>> +  return err;
>
> I was worried about that but thought it wasn't an issue
> as ENOTSUP was not mentioned in the man page :(
> http://www.kernel.org/doc/man-pages/online/pages/man2/utimensat.2.html
>
> Michael can we add ENOTSUP to utimensat(2) ?

Actually, the comment I added above has a typo.
s/ENOTSUP/ENOSYS/.

The diagnostic reported corresponds to ENOSYS.
The adjusted patch is here:

  http://www.redhat.com/archives/fedora-devel-list/2009-August/msg01220.html