Add new function to filter fstab options

This fixes parsing of options in shared/generator.c. Existing code
had some issues:

- it would treate whitespace and semicolons as seperators. fstab(5)
  is pretty clear that only commas matter. And the syntax does
  not allow for spaces to be inserted in the field in fstab.
  Whitespace might be escaped, but then it should not seperate
  options. Treat whitespace and semicolons as any other character.
- it assumed that x-systemd.device-timeout would always be followed
  by "=". But this is not guaranteed, hasmntopt will return this
  option even if there's no value. Uninitialized memory could be read.
- some error paths would log, and inconsistently, some would just
  return an error code.

Filtering is split out to a separate function and tests are added.

Similar code paths in other places are adjusted to use the new function.

5 files changed, 187 insertions, 52 deletions

diff --git a/src/shared/fstab-util.c b/src/shared/fstab-util.c
new file mode 100644
index 0000000000..546c81b80f
--- /dev/null
+++ b/src/shared/fstab-util.c
@@ -0,0 +1,145 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "fstab-util.h"
+#include "strv.h"
+#include "util.h"
+
+int fstab_filter_options(const char *opts, const char *names,
+                         const char **namefound, char **value, char **filtered) {
+        const char *name, *n = NULL, *x;
+        _cleanup_strv_free_ char **stor = NULL;
+        _cleanup_free_ char *v = NULL, **strv = NULL;
+
+        assert(names && *names);
+
+        if (!opts)
+                goto answer;
+
+        /* If !value and !filtered, this function is not allowed to fail. */
+
+        if (!filtered) {
+                const char *word, *state;
+                size_t l;
+
+                FOREACH_WORD_SEPARATOR(word, l, opts, ",", state)
+                        NULSTR_FOREACH(name, names) {
+                                if (l < strlen(name))
+                                        continue;
+                                if (!strneq(word, name, strlen(name)))
+                                        continue;
+
+                                /* we know that the string is NUL
+                                 * terminated, so *x is valid */
+                                x = word + strlen(name);
+                                if (IN_SET(*x, '\0', '=', ',')) {
+                                        n = name;
+                                        if (value) {
+                                                free(v);
+                                                if (IN_SET(*x, '\0', ','))
+                                                        v = NULL;
+                                                else {
+                                                        assert(*x == '=');
+                                                        x++;
+                                                        v = strndup(x, l - strlen(name) - 1);
+                                                        if (!v)
+                                                                return -ENOMEM;
+                                                }
+                                        }
+                                }
+                        }
+        } else {
+                char **t, **s;
+
+                stor = strv_split(opts, ",");
+                if (!stor)
+                        return -ENOMEM;
+                strv = memdup(stor, sizeof(char*) * (strv_length(stor) + 1));
+                if (!strv)
+                        return -ENOMEM;
+
+                for (s = t = strv; *s; s++) {
+                        NULSTR_FOREACH(name, names) {
+                                x = startswith(*s, name);
+                                if (x && IN_SET(*x, '\0', '='))
+                                        goto found;
+                        }
+
+                        *t = *s;
+                        t++;
+                        continue;
+                found:
+                        /* Keep the last occurence found */
+                        n = name;
+                        if (value) {
+                                free(v);
+                                if (*x == '\0')
+                                        v = NULL;
+                                else {
+                                        assert(*x == '=');
+                                        x++;
+                                        v = strdup(x);
+                                        if (!v)
+                                                return -ENOMEM;
+                                }
+                        }
+                }
+                *t = NULL;
+        }
+
+answer:
+        if (namefound)
+                *namefound = n;
+        if (filtered) {
+                char *f;
+
+                f = strv_join(strv, ",");
+                if (!f)
+                        return -ENOMEM;
+
+                *filtered = f;
+        }
+        if (value) {
+                *value = v;
+                v = NULL;
+        }
+
+        return !!n;
+}
+
+int fstab_find_pri(const char *options, int *ret) {
+        _cleanup_free_ char *opt = NULL;
+        int r;
+        unsigned pri;
+
+        assert(ret);
+
+        r = fstab_filter_options(options, "pri\0", NULL, &opt, NULL);
+        if (r <= 0)
+                return r;
+
+        r = safe_atou(opt, &pri);
+        if (r < 0)
+                return r;
+
+        *ret = (int) r;
+        return 1;
+}
diff --git a/src/shared/fstab-util.h b/src/shared/fstab-util.h
new file mode 100644
index 0000000000..39ddb71ef4
--- /dev/null
+++ b/src/shared/fstab-util.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+#include <stddef.h>
+
+int fstab_filter_options(const char *opts, const char *names,
+                         const char **namefound, char **value, char **filtered);
+
+static inline bool fstab_test_option(const char *opts, const char *names) {
+        return !!fstab_filter_options(opts, names, NULL, NULL, NULL);
+}
+
+int fstab_find_pri(const char *options, int *ret);
diff --git a/src/shared/generator.c b/src/shared/generator.c
index 465e5f6cc8..4140afba82 100644
--- a/src/shared/generator.c
+++ b/src/shared/generator.c
@@ -28,6 +28,7 @@
 #include "unit-name.h"
 #include "generator.h"
 #include "path-util.h"
+#include "fstab-util.h"
 #include "dropin.h"
 
 int generator_write_fsck_deps(
@@ -92,42 +93,16 @@ int generator_write_timeouts(const char *dir, const char *what, const char *wher
          * endless device timeouts for devices that show up only after
          * user input, like crypto devices. */
 
-        _cleanup_free_ char *node = NULL, *unit = NULL, *t = NULL;
-        char *start, *timeout;
+        _cleanup_free_ char *node = NULL, *unit = NULL, *timeout = NULL;
         usec_t u;
         int r;
-        size_t len;
-
-        if ((start = mount_test_option(opts, "comment=systemd.device-timeout")))
-                timeout = start + 31;
-        else if ((start = mount_test_option(opts, "x-systemd.device-timeout")))
-                timeout = start + 25;
-        else {
-                if (filtered) {
-                        *filtered = strdup(opts ?: "");
-                        if (!*filtered)
-                                return log_oom();
-                }
 
-                return 0;
-        }
-
-        len = strcspn(timeout, ",;" WHITESPACE);
-        t = strndup(timeout, len);
-        if (!t)
-                return -ENOMEM;
-
-        if (filtered) {
-                char *prefix, *postfix;
+        r = fstab_filter_options(opts, "comment=systemd.device-timeout\0" "x-systemd.device-timeout\0",
+                                 NULL, &timeout, filtered);
+        if (r <= 0)
+                return r;
 
-                prefix = strndupa(opts, start - opts - (start != opts));
-                postfix = timeout + len + (start == opts && timeout[len] != '\0');
-                *filtered = strjoin(prefix, *postfix ? postfix : NULL, NULL);
-                if (!*filtered)
-                        return log_oom();
-        }
-
-        r = parse_sec(t, &u);
+        r = parse_sec(timeout, &u);
         if (r < 0) {
                 log_warning("Failed to parse timeout for %s, ignoring: %s",
                             where, timeout);
@@ -140,7 +115,7 @@ int generator_write_timeouts(const char *dir, const char *what, const char *wher
 
         unit = unit_name_from_path(node, ".device");
         if (!unit)
-                return -ENOMEM;
+                return log_oom();
 
         return write_drop_in_format(dir, unit, 50, "device-timeout",
                                     "# Automatically generated by %s\n\n"
diff --git a/src/shared/util.c b/src/shared/util.c
index 6520e511f0..280e42b305 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -6744,23 +6744,6 @@ uint64_t physical_memory(void) {
         return (uint64_t) mem * (uint64_t) page_size();
 }
 
-char* mount_test_option(const char *haystack, const char *needle) {
-
-        struct mntent me = {
-                .mnt_opts = (char*) haystack
-        };
-
-        assert(needle);
-
-        /* Like glibc's hasmntopt(), but works on a string, not a
-         * struct mntent */
-
-        if (!haystack)
-                return NULL;
-
-        return hasmntopt(&me, needle);
-}
-
 void hexdump(FILE *f, const void *p, size_t s) {
         const uint8_t *b = p;
         unsigned n = 0;
diff --git a/src/shared/util.h b/src/shared/util.h
index 141a3feab6..b337249faa 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -1010,8 +1010,6 @@ const char *personality_to_string(unsigned long);
 
 uint64_t physical_memory(void);
 
-char* mount_test_option(const char *haystack, const char *needle);
-
 void hexdump(FILE *f, const void *p, size_t s);
 
 union file_handle_union {