[COMMITTED] tst-getpw.c: Rewrite.

["Carlos O'Donell" <carlos at redhat dot com>]

The tst-getpw test iterates over 2000 UIDs to look
for one valid one, and one invalid one to test the
getpw function.

The test should stop immediately after it finds
one of each of the testable conditions and terminate
with an appropriate exit code.

On one of my test boxes the local configuration for
NSS is slow enough (sssd over the network) that the test
times out sporadically.

With the rewrite we now test for:
- EINVAL as expected for invalid input.
- One UID that maps.
- One UID that doesn't map.
- Check for other errno values that we don't expect.

This should make the test faster and more stable since
there is bound to be a files-based UID that isn't used
and can be used for the test (rather than going into
the high-numbered UIDs). In the event the system is totally
broken we only iterate over the range of 16-bit UIDs.

Tested on x86_64.

Cheers,
Carlos.

2015-01-21  Carlos O'Donell  <carlos@redhat.com>

        * pwd/tst-getpw.c: Rewrite.

diff --git a/pwd/tst-getpw.c b/pwd/tst-getpw.c
index 059c9e0..e3e101b 100644
--- a/pwd/tst-getpw.c
+++ b/pwd/tst-getpw.c
@@ -15,28 +15,99 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <stdio.h>
 #include <pwd.h>
+#include <errno.h>
+#include <stdbool.h>
+
+/* We want to test getpw by calling it with a uid that does
+   exist and one that doesn't exist. We track if we've met those
+   conditions and exit. We also track if we've failed due to lack
+   of memory. That constitutes all of the standard failure cases.  */
+bool seen_hit;
+bool seen_miss;
+bool seen_oom;
+
+/* How many errors we've had while running the test.  */
+int errors;
 
 static void
 check (uid_t uid)
 {
+  int ret;
   char buf[1024];
 
-  (void) getpw (uid, buf);
+  ret = getpw (uid, buf);
+
+  /* Successfully read a password line.  */
+  if (ret == 0 && !seen_hit)
+    {
+      printf ("PASS: Read a password line given a uid.\n");
+      seen_hit = true;
+    }
+
+  /* Failed to read a password line. Why?  */
+  if (ret == -1)
+    {
+      /* No entry?  Technically the errno could be any number
+	 of values including ESRCH, EBADP or EPERM depending
+	 on the quality of the nss module that implements the
+	 underlying lookup. It should be 0 for getpw.*/
+      if (errno == 0 && !seen_miss)
+	{
+	  printf ("PASS: Found an invalid uid.\n");
+	  seen_miss = true;
+	  return;
+	}
+
+      /* Out of memory?  */
+      if (errno == ENOMEM && !seen_oom)
+	{
+	  printf ("FAIL: Failed with ENOMEM.\n");
+	  seen_oom = true;
+	  errors++;
+	}
+
+      /* We don't expect any other values for errno.  */
+      if (errno != ENOMEM && errno != 0)
+	errors++;
+    }
 }
 
 static int
 do_test (void)
 {
+  int ret;
   uid_t uid;
 
-  /* Just call it a different number of times the range should be
-     large enough to find some existing and some non existing uids.  */
+  /* Should return -1 and set errnot to EINVAL.  */
+  ret = getpw (0, NULL);
+  if (ret == -1 && errno == EINVAL)
+    {
+      printf ("PASS: NULL buffer returns -1 and sets errno to EINVAL.\n");
+    }
+  else
+    {
+      printf ("FAIL: NULL buffer did not return -1 or set errno to EINVAL.\n");
+      errors++;
+    }
+
+  /* Look for one matching uid, one non-found uid and then stop.
+     Set an upper limit at the 16-bit UID mark; no need to go farther.  */
+  for (uid = 0; uid < ((uid_t) 65535); ++uid)
+    {
+      check (uid);
+      if (seen_miss && seen_hit)
+	break;
+    }
+
+  if (!seen_hit)
+    printf ("FAIL: Did not read even one password line given a uid.\n");
 
-  for (uid = 0; uid < 2000; ++uid)
-    check (uid);
+  if (!seen_miss)
+    printf ("FAIL: Did not find even one invalid uid.\n");
 
-  return 0;
+  return errors;
 }
 
 #define TEST_FUNCTION do_test ()
---