mount: implement -O, --test-opts

--test-opts in combination with --all mounts only those filesystems
with options matching the given set of options.

Note that the semantic of the inverting "no" prefix differs from
--types: While --types=nonfs,ufs means neither nfs nor ufs,
--test-opts=nofoo,bar means not foo, but bar.

* utils/match-options.h: New file.
* utils/match-options.c: Likewise.
(test_opts): New variable.
(test_opts_len): Likewise.
(match_options): New function.
* utils/mount.c (parse_opt): Handle -O, --test-opts.
(main): Use match_options as filter.

1 files changed, 68 insertions, 0 deletions

diff --git a/utils/match-options.c b/utils/match-options.c
new file mode 100644
index 00000000..11fc9dcb
--- /dev/null
+++ b/utils/match-options.c
@@ -0,0 +1,68 @@
+/* Common functionality for the --test-opts flag of mount and umount.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include <argz.h>
+#include <error.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "match-options.h"
+
+char *test_opts;
+size_t test_opts_len;
+
+int
+match_options (struct mntent *mntent)
+{
+  char *opts;
+  size_t opts_len;
+
+  error_t err = argz_create_sep (mntent->mnt_opts, ',', &opts, &opts_len);
+  if (err)
+    error (3, err, "parsing mount options failed");
+
+  for (char *test = test_opts;
+       test; test = argz_next (test_opts, test_opts_len, test))
+    {
+      char *needle = test;
+      int inverse = strncmp("no", needle, 2) == 0;
+      if (inverse)
+        needle += 2;
+
+      int match = 0;
+      for (char *opt = opts; opt; opt = argz_next (opts, opts_len, opt))
+        {
+          if (strcmp (opt, needle) == 0) {
+            if (inverse)
+              return 0; /* foo in opts, nofoo in test_opts. */
+
+            /* foo in opts, foo in test_opts, record match. */
+            match = 1;
+          }
+        }
+
+      if (! inverse && ! match)
+        return 0; /* No foo in opts, but foo in test_opts. */
+    }
+
+  /* If no conflicting test_opt was encountered, return success. */
+  return 1;
+}