Support negated fstab options

We would ignore options like "fail" and "auto", and for any option
which takes a value the first assignment would win. Repeated and
options equivalent to the default are rarely used, but they have been
documented forever, and people might use them. Especially on the
kernel command line it is easier to append a repeated or negated
option at the end.

src/cryptsetup/cryptsetup-generator.c

@@ -67,8 +67,8 @@ static int create_disk(
         assert(name);
         assert(device);
 
-        noauto = fstab_test_option(options, "noauto\0");
-        nofail = fstab_test_option(options, "nofail\0");
+        noauto = fstab_test_yes_no_option(options, "noauto\0" "auto\0");
+        nofail = fstab_test_yes_no_option(options, "nofail\0" "fail\0");
         tmp = fstab_test_option(options, "tmp\0");
         swap = fstab_test_option(options, "swap\0");
 

src/cryptsetup/cryptsetup.c

@@ -69,7 +69,7 @@ static int parse_one_option(const char *option) {
         assert(option);
 
         /* Handled outside of this tool */
-        if (streq(option, "noauto") || streq(option, "nofail"))
+        if (STR_IN_SET(option, "noauto", "auto", "nofail", "fail"))
                 return 0;
 
         if (startswith(option, "cipher=")) {

src/fstab-generator/fstab-generator.c

@@ -135,17 +135,15 @@ static int add_swap(
 static bool mount_is_network(struct mntent *me) {
         assert(me);
 
-        return
-                hasmntopt(me, "_netdev") ||
-                fstype_is_network(me->mnt_type);
+        return fstab_test_option(me->mnt_opts, "_netdev\0") ||
+               fstype_is_network(me->mnt_type);
 }
 
 static bool mount_in_initrd(struct mntent *me) {
         assert(me);
 
-        return
-                hasmntopt(me, "x-initrd.mount") ||
-                streq(me->mnt_dir, "/usr");
+        return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
+               streq(me->mnt_dir, "/usr");
 }
 
 static int add_mount(
@@ -344,8 +342,8 @@ static int parse_fstab(bool initrd) {
                 if (is_path(where))
                         path_kill_slashes(where);
 
-                noauto = !!hasmntopt(me, "noauto");
-                nofail = !!hasmntopt(me, "nofail");
+                noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
+                nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");
                 log_debug("Found entry what=%s where=%s type=%s nofail=%s noauto=%s",
                           what, where, me->mnt_type,
                           yes_no(noauto), yes_no(nofail));
@@ -356,10 +354,9 @@ static int parse_fstab(bool initrd) {
                         bool automount;
                         const char *post;
 
-                        automount =
-                                  hasmntopt(me, "comment=systemd.automount") ||
-                                  hasmntopt(me, "x-systemd.automount");
-
+                        automount = fstab_test_option(me->mnt_opts,
+                                                      "comment=systemd.automount\0"
+                                                      "x-systemd.automount\0");
                         if (initrd)
                                 post = SPECIAL_INITRD_FS_TARGET;
                         else if (mount_in_initrd(me))

src/shared/fstab-util.h

@@ -23,6 +23,7 @@
 
 #include <stdbool.h>
 #include <stddef.h>
+#include "macro.h"
 
 int fstab_filter_options(const char *opts, const char *names,
                          const char **namefound, char **value, char **filtered);
@@ -32,3 +33,16 @@ static inline bool fstab_test_option(const char *opts, const char *names) {
 }
 
 int fstab_find_pri(const char *options, int *ret);
+
+static inline bool fstab_test_yes_no_option(const char *opts, const char *yes_no) {
+        int r;
+        const char *opt;
+
+        /* If first name given is last, return 1.
+         * If second name given is last or neither is found, return 0. */
+
+        r = fstab_filter_options(opts, yes_no, &opt, NULL, NULL);
+        assert(r >= 0);
+
+        return opt == yes_no;
+}

src/test/test-fstab-util.c

@@ -107,6 +107,15 @@ static void test_fstab_filter_options(void) {
         do_fstab_filter_options("", "opt\0", 0, NULL, NULL, "");
 }
 
+static void test_fstab_yes_no_option(void) {
+        assert_se(fstab_test_yes_no_option("nofail,fail,nofail", "nofail\0fail\0") == true);
+        assert_se(fstab_test_yes_no_option("nofail,nofail,fail", "nofail\0fail\0") == false);
+        assert_se(fstab_test_yes_no_option("abc,cde,afail", "nofail\0fail\0") == false);
+        assert_se(fstab_test_yes_no_option("nofail,fail=0,nofail=0", "nofail\0fail\0") == true);
+        assert_se(fstab_test_yes_no_option("nofail,nofail=0,fail=0", "nofail\0fail\0") == false);
+}
+
 int main(void) {
         test_fstab_filter_options();
+        test_fstab_yes_no_option();
 }