Re: Problem with fstatat on AIX 7.1

[Paul Eggert]

On 08/31/11 07:06, Kevin Brott wrote:
> If we do not use fstatat then tar builds and passes almost all of the checks 
> (only the two sparse file ones fail).
> If we use fstatat, then almost all of the checks fail - because the resulting 
> binary is dropping zero-byte files into the archives, and doesn't function.
> 
> So either there is a bug or enough of a fundamental difference in the way AIX 
> 7.1's new fstatat call works, that it's not usable with the way the existing 
> GNU tar code is trying to use it.

It semmed pretty clear there is a bug there.
Unfortunately, the test program does not seem to expose the bug.

How about this test program instead?  Please run it in a directory
where conftest.file has been created via "echo xxx >conftest.file".

If this test program works on AIX 7.1, can you modify it in a minor
way so that it correctly exposes the AIX bug?  There must be some
way to do it, since 'tar' is doing it.

  #include <fcntl.h>
  #include <sys/stat.h>

  int
  main (void)
  {
    struct stat a;
    struct stat b;
    int fd = open (".", O_RDONLY);

    if (fd < 0)
      return 10;
    if (fstatat (fd, "conftest.file", &a,
                 AT_SYMLINK_NOFOLLOW)
        != 0)
      return 1;
    if (lstat ("conftest.file", &b) != 0)
      return 2;
    if (a.st_size != b.st_size) return 3;
    if (a.st_dev != b.st_dev) return 4;
    if (a.st_ino != b.st_ino) return 5;
    if (a.st_mode != b.st_mode) return 6;
    if (a.st_nlink != b.st_nlink) return 7;
    if (a.st_uid != b.st_uid) return 8;
    if (a.st_gid != b.st_gid) return 9;
    /* Don't check time members, to avoid caching issues.  */
    return 0;
  }