support: Don't fail on fchown when spawning sgid processes

In some cases (e.g. when podman creates user containers), the only other
group assigned to the executing user is nobody and fchown fails with it
because the group is not mapped.  Do not fail the test in this case,
instead exit as unsupported.

Reported-by: Frédéric Bérat <fberat@redhat.com>
Tested-by: Frédéric Bérat <fberat@redhat.com>
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

diff --git a/support/support_capture_subprocess.c b/support/support_capture_subprocess.c
index bae7d5fb203fe3544c01765058d70ac908cf9c2c..2a8d37b284a7627f12a33dc4639418fae0945ae6 100644 (file)
--- a/support/support_capture_subprocess.c
+++ b/support/support_capture_subprocess.c
@@ -153,9 +153,18 @@ copy_and_spawn_sgid (char *child_id, gid_t gid)
          p += wrcount;
        }
     }
-  TEST_VERIFY (fchown (outfd, getuid (), gid) == 0);
+
+  bool chowned = false;
+  TEST_VERIFY ((chowned = fchown (outfd, getuid (), gid) == 0)
+              || errno == EPERM);
   if (support_record_failure_is_failed ())
     goto err;
+  else if (!chowned)
+    {
+      ret = 77;
+      goto err;
+    }
+
   TEST_VERIFY (fchmod (outfd, 02750) == 0);
   if (support_record_failure_is_failed ())
     goto err;
@@ -192,8 +201,10 @@ err:
       free (dirname);
     }
 
+  if (ret == 77)
+    FAIL_UNSUPPORTED ("Failed to make sgid executable for test\n");
   if (ret != 0)
-    FAIL_EXIT1("Failed to make sgid executable for test\n");
+    FAIL_EXIT1 ("Failed to make sgid executable for test\n");
 
   return status;
 }