Bug 437945

Description of problem:
nis+-based getgrent mistakenly sets errno when there are no more entries
This is the root cause of a bug reported against coreutils:

  http://savannah.gnu.org/bugs/?22505

Version-Release number of selected component (if applicable):
glibc-2.7.90-9.x86_64 (but also affects at least RHEL4.6 and FC5)

How reproducible: every time

Here's code to demonstrate the bug:

cat <<\EOF > getgrent-test.c
#include <sys/types.h>
#include <grp.h>
#include <errno.h>
#include <stdio.h>

static int
count_groups (void)
{
  int count = 0;

  setgrent ();
  while (1)
    {
      errno = 0;
      struct group *grp = getgrent ();
      if (!grp)
        break;
      ++count;
    }

  if (errno != 0)
    {
      perror ("getgrent failed");
      count = -1;
    }

  int saved_errno = errno;
  endgrent ();
  errno = saved_errno;

  return count;
}

int
main ()
{
  return count_groups () < 0;
}
EOF
gcc -O -W -Wall getgrent-test.c && ./a.out && echo ok
======================================

When I run that on a rawhide system on which /etc/nsswitch.conf has this:

  group: files

I get an exit status of 0, as expected.
However, when I change nsswitch.conf, appending " nisplus"
(and I haven't configured NIS+ at all):

  group: files nisplus

and run ./a.out again, I get this output:

  getgrent failed: No such file or directory
  [Exit 1]




Additional info: