Re: [Bug-tar] [GNU tar 1.26] testsuite: 39 failed

[Paul Eggert]

On 07/26/2012 03:33 AM, Jez Wain wrote:
> On the new server, which produced the erroneous result,
> fcntl.h defines both O_NOFOLLOW and AT_SYMLINK_NOFOLLOW

OK, thanks, but why do you later mention
_XOPEN_SOURCE?  Is that relevant?

It sounds like we need to add a test for this AIX bug,
and then put a workaround into tar.  Let's start with the
test.  Suppose you compile the following test program:

  #include <fcntl.h>

  int
  main (void)
  {
    int flags = O_NOFOLLOW | O_WRONLY | O_CREAT;
    mode_t perms = S_IRUSR | S_IWUSR;
    return openat (AT_FDCWD, "symlink", flags, perms) < 0 ? 0 : 1;
  }

Put this into a.out, and then run these shell commands:

   rm -f file symlink
   touch file
   ln -s file symlink
   truss ./a.out

What does the tail end of the "truss" output say,
starting with the first mention of "symlink"?
On a working system, openat should fail and the
program should exit with status 0.  My guess is
that on AIX openat succeeds, and the program exits
with status 1.