Fix error reporting (false negatives) in SGID testsrelease/2.35/master

And simplify the interface of support_capture_subprogram_self_sgid.

Use the existing framework for temporary directories (now with
mode 0700) and directory/file deletion.  Handle all execution
errors within support_capture_subprogram_self_sgid.  In particular,
this includes test failures because the invoked program did not
exit with exit status zero.  Existing tests that expect exit
status 42 are adjusted to use zero instead.

In addition, fix callers not to call exit (0) with test failures
pending (which may mask them, especially when running with --direct).

Fixes commit 35fc356fa3b4f485bd3ba3114c9f774e5df7d3c2
("elf: Fix subprocess status handling for tst-dlopen-sgid (bug 32987)").

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 3a3fb2ed83f79100c116c824454095ecfb335ad7)

6 files changed, 36 insertions, 125 deletions

diff --git a/elf/tst-dlopen-sgid.c b/elf/tst-dlopen-sgid.c
index 5688b79..8aec52e 100644
--- a/elf/tst-dlopen-sgid.c
+++ b/elf/tst-dlopen-sgid.c
@@ -70,13 +70,7 @@ do_test (void)
 
   free (libdir);
 
-  int status = support_capture_subprogram_self_sgid (magic_argument);
-
-  if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
-    return EXIT_UNSUPPORTED;
-
-  if (!WIFEXITED (status))
-    FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status);
+  support_capture_subprogram_self_sgid (magic_argument);
 
   return 0;
 }
diff --git a/elf/tst-env-setuid-tunables.c b/elf/tst-env-setuid-tunables.c
index 5e9e4c5..bca299b 100644
--- a/elf/tst-env-setuid-tunables.c
+++ b/elf/tst-env-setuid-tunables.c
@@ -127,10 +127,7 @@ do_test (int argc, char **argv)
 
       if (ret != 0)
 	exit (1);
-
-      /* Special return code to make sure that the child executed all the way
-	 through.  */
-      exit (42);
+      return 0;
     }
   else
     {
@@ -149,18 +146,7 @@ do_test (int argc, char **argv)
 	      continue;
 	    }
 
-	  int status = support_capture_subprogram_self_sgid (buf);
-
-	  /* Bail out early if unsupported.  */
-	  if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
-	    return EXIT_UNSUPPORTED;
-
-	  if (WEXITSTATUS (status) != 42)
-	    {
-	      printf ("    [%d] child failed with status %d\n", i,
-		      WEXITSTATUS (status));
-	      support_record_failure ();
-	    }
+	  support_capture_subprogram_self_sgid (buf);
 	}
       return 0;
     }
diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c
index 53fc527..8ed4d48 100644
--- a/elf/tst-env-setuid.c
+++ b/elf/tst-env-setuid.c
@@ -104,20 +104,14 @@ do_test (int argc, char **argv)
       if (ret != 0)
 	exit (1);
 
-      exit (EXIT_SUCCESS);
+      return 0;
     }
   else
     {
       if (test_parent () != 0)
 	exit (1);
 
-      int status = support_capture_subprogram_self_sgid (SETGID_CHILD);
-
-      if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
-	return EXIT_UNSUPPORTED;
-
-      if (!WIFEXITED (status))
-	FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status);
+      support_capture_subprogram_self_sgid (SETGID_CHILD);
 
       return 0;
     }
diff --git a/stdlib/tst-secure-getenv.c b/stdlib/tst-secure-getenv.c
index 69719a8..ed4728c 100644
--- a/stdlib/tst-secure-getenv.c
+++ b/stdlib/tst-secure-getenv.c
@@ -57,13 +57,7 @@ do_test (void)
       exit (1);
     }
 
-  int status = support_capture_subprogram_self_sgid (MAGIC_ARGUMENT);
-
-  if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
-    return EXIT_UNSUPPORTED;
-
-  if (!WIFEXITED (status))
-    FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status);
+  support_capture_subprogram_self_sgid (MAGIC_ARGUMENT);
 
   return 0;
 }
@@ -82,6 +76,7 @@ alternative_main (int argc, char **argv)
       if (secure_getenv ("PATH") != NULL)
 	FAIL_EXIT (4, "PATH variable not filtered out\n");
 
+      support_record_failure_barrier ();
       exit (EXIT_SUCCESS);
     }
 }
diff --git a/support/capture_subprocess.h b/support/capture_subprocess.h
index 037b9c2..8cae175 100644
--- a/support/capture_subprocess.h
+++ b/support/capture_subprocess.h
@@ -41,10 +41,12 @@ struct support_capture_subprocess support_capture_subprocess
 struct support_capture_subprocess support_capture_subprogram
   (const char *file, char *const argv[]);
 
-/* Copy the running program into a setgid binary and run it with CHILD_ID
-   argument.  If execution is successful, return the exit status of the child
-   program, otherwise return a non-zero failure exit code.  */
-int support_capture_subprogram_self_sgid (const char *child_id);
+/* Copy the running program into a setgid binary and run it with
+   CHILD_ID argument.  If the program exits with a non-zero status,
+   exit with that exit status (or status 1 if the program did not exit
+   normally).  If the test cannot be performed, exit with
+   EXIT_UNSUPPORTED.  */
+void support_capture_subprogram_self_sgid (const char *child_id);
 
 /* Deallocate the subprocess data captured by
    support_capture_subprocess.  */
diff --git a/support/support_capture_subprocess.c b/support/support_capture_subprocess.c
index 4929790..424d6a9 100644
--- a/support/support_capture_subprocess.c
+++ b/support/support_capture_subprocess.c
@@ -31,6 +31,7 @@
 #include <support/xsocket.h>
 #include <support/xspawn.h>
 #include <support/support.h>
+#include <support/temp_file.h>
 #include <support/test-driver.h>
 
 static void
@@ -112,105 +113,44 @@ support_capture_subprogram (const char *file, char *const argv[])
 /* Copies the executable into a restricted directory, so that we can
    safely make it SGID with the TARGET group ID.  Then runs the
    executable.  */
-static int
+static void
 copy_and_spawn_sgid (const char *child_id, gid_t gid)
 {
-  char *dirname = xasprintf ("%s/tst-tunables-setuid.%jd",
-			     test_dir, (intmax_t) getpid ());
+  char *dirname = support_create_temp_directory ("tst-glibc-sgid-");
   char *execname = xasprintf ("%s/bin", dirname);
-  int infd = -1;
-  int outfd = -1;
-  int ret = 1, status = 1;
-
-  TEST_VERIFY (mkdir (dirname, 0700) == 0);
-  if (support_record_failure_is_failed ())
-    goto err;
+  add_temp_file (execname);
 
-  infd = open ("/proc/self/exe", O_RDONLY);
-  if (infd < 0)
+  if (access ("/proc/self/exe", R_OK) != 0)
     FAIL_UNSUPPORTED ("unsupported: Cannot read binary from procfs\n");
 
-  outfd = open (execname, O_WRONLY | O_CREAT | O_EXCL, 0700);
-  TEST_VERIFY (outfd >= 0);
-  if (support_record_failure_is_failed ())
-    goto err;
-
-  char buf[4096];
-  for (;;)
-    {
-      ssize_t rdcount = read (infd, buf, sizeof (buf));
-      TEST_VERIFY (rdcount >= 0);
-      if (support_record_failure_is_failed ())
-	goto err;
-      if (rdcount == 0)
-	break;
-      char *p = buf;
-      char *end = buf + rdcount;
-      while (p != end)
-	{
-	  ssize_t wrcount = write (outfd, buf, end - p);
-	  if (wrcount == 0)
-	    errno = ENOSPC;
-	  TEST_VERIFY (wrcount > 0);
-	  if (support_record_failure_is_failed ())
-	    goto err;
-	  p += wrcount;
-	}
-    }
+  support_copy_file ("/proc/self/exe", execname);
 
-  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;
-    }
+  if (chown (execname, getuid (), gid) != 0)
+    FAIL_UNSUPPORTED ("cannot change group of \"%s\" to %jd: %m",
+		      execname, (intmax_t) gid);
 
-  TEST_VERIFY (fchmod (outfd, 02750) == 0);
-  if (support_record_failure_is_failed ())
-    goto err;
-  TEST_VERIFY (close (outfd) == 0);
-  if (support_record_failure_is_failed ())
-    goto err;
-  TEST_VERIFY (close (infd) == 0);
-  if (support_record_failure_is_failed ())
-    goto err;
+  if (chmod (execname, 02750) != 0)
+    FAIL_UNSUPPORTED ("cannot make \"%s\" SGID: %m ", execname);
 
   /* We have the binary, now spawn the subprocess.  Avoid using
      support_subprogram because we only want the program exit status, not the
      contents.  */
-  ret = 0;
-  infd = outfd = -1;
 
   char * const args[] = {execname, (char *) child_id, NULL};
+  int status = support_subprogram_wait (args[0], args);
 
-  status = support_subprogram_wait (args[0], args);
+  free (execname);
+  free (dirname);
 
-err:
-  if (outfd >= 0)
-    close (outfd);
-  if (infd >= 0)
-    close (infd);
-  if (execname != NULL)
-    {
-      unlink (execname);
-      free (execname);
-    }
-  if (dirname != NULL)
+  if (WIFEXITED (status))
     {
-      rmdir (dirname);
-      free (dirname);
+      if (WEXITSTATUS (status) == 0)
+	return;
+      else
+	exit (WEXITSTATUS (status));
     }
-
-  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");
-
-  return status;
+  else
+    FAIL_EXIT1 ("subprogram failed with status %d", status);
 }
 
 /* Returns true if a group with NAME has been found, and writes its
@@ -252,7 +192,7 @@ find_sgid_group (gid_t *target, const char *name)
   return ok;
 }
 
-int
+void
 support_capture_subprogram_self_sgid (const char *child_id)
 {
   const int count = 64;
@@ -287,7 +227,7 @@ support_capture_subprogram_self_sgid (const char *child_id)
 			 (intmax_t) getuid ());
     }
 
-  return copy_and_spawn_sgid (child_id, target);
+  copy_and_spawn_sgid (child_id, target);
 }
 
 void