mount: support "-O option"; stop trying to mount swap partitions

function                                             old     new   delta
mount_main                                           975    1152    +177
umount_main                                          640     636      -4
packed_usage                                       25666   25662      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 177/-8)            Total: 169 bytes

4 files changed, 136 insertions, 60 deletions

diff --git a/include/usage.h b/include/usage.h
index e945840b8..25a716278 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2796,45 +2796,50 @@
        "$ dmesg | more\n"
 
 #define mount_trivial_usage \
-       "[flags] DEVICE NODE [-o options,more-options]"
+       "[flags] DEVICE NODE [-o OPT,OPT]"
 #define mount_full_usage "\n\n" \
        "Mount a filesystem. Filesystem autodetection requires /proc be mounted.\n" \
      "\nOptions:" \
      "\n        -a              Mount all filesystems in fstab" \
         USE_FEATURE_MOUNT_FAKE( \
-     "\n        -f              "USE_FEATURE_MTAB_SUPPORT("Update /etc/mtab, but ")"don't mount" \
+        USE_FEATURE_MTAB_SUPPORT( \
+     "\n        -f              Update /etc/mtab, but don't mount" \
+        ) \
+        SKIP_FEATURE_MTAB_SUPPORT( \
+     "\n        -f              Dry run" \
+        ) \
         ) \
         USE_FEATURE_MTAB_SUPPORT( \
      "\n        -n              Don't update /etc/mtab" \
         ) \
      "\n        -r              Read-only mount" \
-     "\n        -t fs-type      Filesystem type" \
      "\n        -w              Read-write mount (default)" \
-       "\n" \
-       "-o option:\n" \
+     "\n        -t FSTYPE       Filesystem type" \
+     "\n        -O OPT          Mount only filesystems with option OPT (-a only)" \
+     "\n-o OPT:" \
         USE_FEATURE_MOUNT_LOOP( \
-       "        loop            Ignored (loop devices are autodetected)\n" \
+     "\n        loop            Ignored (loop devices are autodetected)" \
         ) \
         USE_FEATURE_MOUNT_FLAGS( \
-       "        [a]sync         Writes are asynchronous / synchronous\n" \
-       "        [no]atime       Disable / enable updates to inode access times\n" \
-       "        [no]diratime    Disable / enable atime updates to directories\n" \
-       "        [no]relatime    Disable / enable atime updates relative to modification time\n" \
-       "        [no]dev         Allow use of special device files / disallow them\n" \
-       "        [no]exec        Allow use of executable files / disallow them\n" \
-       "        [no]suid        Allow set-user-id-root programs / disallow them\n" \
-       "        [r]shared       Convert [recursively] to a shared subtree\n" \
-       "        [r]slave        Convert [recursively] to a slave subtree\n" \
-       "        [r]private      Convert [recursively] to a private subtree\n" \
-       "        [un]bindable    Make mount point [un]able to be bind mounted\n" \
-       "        bind            Bind a directory to an additional location\n" \
-       "        move            Relocate an existing mount point\n" \
+     "\n        [a]sync         Writes are [a]synchronous" \
+     "\n        [no]atime       Disable/enable updates to inode access times" \
+     "\n        [no]diratime    Disable/enable atime updates to directories" \
+     "\n        [no]relatime    Disable/enable atime updates relative to modification time" \
+     "\n        [no]dev         (Dis)allow use of special device files" \
+     "\n        [no]exec        (Dis)allow use of executable files" \
+     "\n        [no]suid        (Dis)allow set-user-id-root programs" \
+     "\n        [r]shared       Convert [recursively] to a shared subtree" \
+     "\n        [r]slave        Convert [recursively] to a slave subtree" \
+     "\n        [r]private      Convert [recursively] to a private subtree" \
+     "\n        [un]bindable    Make mount point [un]able to be bind mounted" \
+     "\n        bind            Bind a directory to an additional location" \
+     "\n        move            Relocate an existing mount point" \
         ) \
-       "        remount         Remount a mounted filesystem, changing its flags\n" \
-       "        ro/rw           Mount for read-only / read-write\n" \
-       "\n" \
-       "There are EVEN MORE flags that are specific to each filesystem\n" \
-       "You'll have to see the written documentation for those filesystems" \
+     "\n        remount         Remount a mounted filesystem, changing its flags" \
+     "\n        ro/rw           Read-only/read-write mount" \
+     "\n" \
+     "\nThere are EVEN MORE flags that are specific to each filesystem" \
+     "\nYou'll have to see the written documentation for those filesystems" \
 
 #define mount_example_usage \
        "$ mount\n" \
diff --git a/libbb/match_fstype.c b/libbb/match_fstype.c
index 99e276784..9360e757a 100644
--- a/libbb/match_fstype.c
+++ b/libbb/match_fstype.c
@@ -5,40 +5,38 @@
  * This allows us to match fstypes that start with no like so
  *   mount -at ,noddy
  *
- * Returns 0 for a match, otherwise -1
+ * Returns 1 for a match, otherwise 0
  *
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
 #include "libbb.h"
 
-int FAST_FUNC match_fstype(const struct mntent *mt, const char *fstype)
+int FAST_FUNC match_fstype(const struct mntent *mt, const char *t_fstype)
 {
-        int no = 0;
+        int match = 1;
         int len;
 
-        if (!mt)
-                return -1;
+        if (!t_fstype)
+                return match;
 
-        if (!fstype)
-                return 0;
-
-        if (fstype[0] == 'n' && fstype[1] == 'o') {
-                no = -1;
-                fstype += 2;
+        if (t_fstype[0] == 'n' && t_fstype[1] == 'o') {
+                match--;
+                t_fstype += 2;
         }
 
         len = strlen(mt->mnt_type);
-        while (fstype) {
-                if (!strncmp(mt->mnt_type, fstype, len)
-                 && (!fstype[len] || fstype[len] == ',')
+        while (1) {
+                if (strncmp(mt->mnt_type, t_fstype, len) == 0
+                 && (t_fstype[len] == '\0' || t_fstype[len] == ',')
                 ) {
-                        return no;
+                        return match;
                 }
-                fstype = strchr(fstype, ',');
-                if (fstype)
-                        fstype++;
+                t_fstype = strchr(t_fstype, ',');
+                if (!t_fstype)
+                        break;
+                t_fstype++;
         }
 
-        return -(no + 1);
+        return !match;
 }
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 3b8311318..d647c71b1 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -63,7 +63,7 @@ enum {
 };
 
 
-#define OPTION_STR "o:t:rwanfvsi"
+#define OPTION_STR "o:t:rwanfvsiO:"
 enum {
         OPT_o = (1 << 0),
         OPT_t = (1 << 1),
@@ -75,6 +75,7 @@ enum {
         OPT_v = (1 << 7),
         OPT_s = (1 << 8),
         OPT_i = (1 << 9),
+        OPT_O = (1 << 10),
 };
 
 #if ENABLE_FEATURE_MTAB_SUPPORT
@@ -1721,6 +1722,45 @@ static int singlemount(struct mntent *mp, int ignore_busy)
         return rc;
 }
 
+/* -O support
+ * Unlike -t, -O should interpret "no" prefix differently:
+ * -t noa,b,c = -t no(a,b,c) = mount all except fs'es with types a,b, and c
+ * -O noa,b,c = -O noa,b,c = mount all with without option a,
+ * or with option b or c.
+ * But for now we do not support -O a,b,c at all (only -O a).
+ *
+ * Another difference from -t support (match_fstype) is that
+ * we need to examine the _list_ of options in fsopt, not just a string.
+ */
+static int match_opt(const char *fs_opt, const char *O_opt)
+{
+        int match = 1;
+        int len;
+
+        if (!O_opt)
+                return match;
+
+        if (O_opt[0] == 'n' && O_opt[1] == 'o') {
+                match--;
+                O_opt += 2;
+        }
+
+        len = strlen(O_opt);
+        while (1) {
+                if (strncmp(fs_opt, O_opt, len) == 0
+                 && (fs_opt[len] == '\0' || fs_opt[len] == ',')
+                ) {
+                        return match;
+                }
+                fs_opt = strchr(fs_opt, ',');
+                if (!fs_opt)
+                        break;
+                fs_opt++;
+        }
+
+        return !match;
+}
+
 // Parse options, if necessary parse fstab/mtab, and call singlemount for
 // each directory to be mounted.
 static const char must_be_root[] ALIGN1 = "you must be root";
@@ -1728,8 +1768,9 @@ static const char must_be_root[] ALIGN1 = "you must be root";
 int mount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int mount_main(int argc UNUSED_PARAM, char **argv)
 {
-        char *cmdopts = xstrdup("");
+        char *cmdopts = xzalloc(1);
         char *fstype = NULL;
+        char *O_optmatch = NULL;
         char *storage_path;
         llist_t *lst_o = NULL;
         const char *fstabname;
@@ -1752,9 +1793,9 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
         argv[j] = NULL;
 
         // Parse remaining options
-        // Max 2 params; -v is a counter
-        opt_complementary = "?2o::" USE_FEATURE_MOUNT_VERBOSE(":vv");
-        opt = getopt32(argv, OPTION_STR, &lst_o, &fstype
+        // Max 2 params; -o is a list, -v is a counter
+        opt_complementary = "?2o::" USE_FEATURE_MOUNT_VERBOSE("vv");
+        opt = getopt32(argv, OPTION_STR, &lst_o, &fstype, &O_optmatch
                         USE_FEATURE_MOUNT_VERBOSE(, &verbose));
         while (lst_o) append_mount_options(&cmdopts, llist_pop(&lst_o)); // -o
         if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
@@ -1807,7 +1848,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
         // Past this point, we are handling either "mount -a [opts]"
         // or "mount [opts] single_param"
 
-        i = parse_mount_options(cmdopts, 0); // FIXME: should be "long", not "int"
+        i = parse_mount_options(cmdopts, NULL); // FIXME: should be "long", not "int"
         if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
                 bb_error_msg_and_die(must_be_root);
 
@@ -1865,20 +1906,29 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
 
                 // If we're mounting all
                 } else {
-                        // Do we need to match a filesystem type?
-                        if (fstype && match_fstype(mtcur, fstype))
+                        // No, mount -a won't mount anything,
+                        // even user mounts, for mere humans
+                        if (nonroot)
+                                bb_error_msg_and_die(must_be_root);
+
+                        // Does type match? (NULL matches always)
+                        if (!match_fstype(mtcur, fstype))
                                 continue;
 
                         // Skip noauto and swap anyway.
-                        if (parse_mount_options(mtcur->mnt_opts, 0) & (MOUNT_NOAUTO | MOUNT_SWAP))
+                        if ((parse_mount_options(mtcur->mnt_opts, NULL) & (MOUNT_NOAUTO | MOUNT_SWAP))
+                        // swap is bogus "fstype", parse_mount_options can't check fstypes
+                         || strcasecmp(mtcur->mnt_type, "swap") == 0
+                        ) {
                                 continue;
+                        }
 
-                        // No, mount -a won't mount anything,
-                        // even user mounts, for mere humans
-                        if (nonroot)
-                                bb_error_msg_and_die(must_be_root);
+                        // Does (at least one) option match?
+                        // (NULL matches always)
+                        if (!match_opt(mtcur->mnt_opts, O_optmatch))
+                                continue;
 
-                        resolve_mount_spec(&mtpair->mnt_fsname);
+                        resolve_mount_spec(&mtcur->mnt_fsname);
 
                         // NFS mounts want this to be xrealloc-able
                         mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
@@ -1895,13 +1945,35 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
         // End of fstab/mtab is reached.
         // Were we looking for something specific?
         if (argv[0]) {
+                long l;
+
                 // If we didn't find anything, complain
                 if (!mtcur->mnt_fsname)
                         bb_error_msg_and_die("can't find %s in %s",
                                 argv[0], fstabname);
+
+                // What happens when we try to "mount swap_partition"?
+                // (fstab containts "swap_partition swap swap defaults 0 0")
+                // util-linux-ng 2.13.1 does this:
+                // stat("/sbin/mount.swap", 0x7fff62a3a350) = -1 ENOENT (No such file or directory)
+                // mount("swap_partition", "swap", "swap", MS_MGC_VAL, NULL) = -1 ENOENT (No such file or directory)
+                // lstat("swap", 0x7fff62a3a640)           = -1 ENOENT (No such file or directory)
+                // write(2, "mount: mount point swap does not exist\n", 39) = 39
+                // exit_group(32)                          = ?
+#if 0
+                // In case we want to simply skip swap partitions:
+                l = parse_mount_options(mtcur->mnt_opts, NULL);
+                if ((l & MOUNT_SWAP)
+                // swap is bogus "fstype", parse_mount_options can't check fstypes
+                 || strcasecmp(mtcur->mnt_type, "swap") == 0
+                ) {
+                        goto ret;
+                }
+#endif
                 if (nonroot) {
                         // fstab must have "users" or "user"
-                        if (!(parse_mount_options(mtcur->mnt_opts, 0) & MOUNT_USERS))
+                        l = parse_mount_options(mtcur->mnt_opts, NULL);
+                        if (!(l & MOUNT_USERS))
                                 bb_error_msg_and_die(must_be_root);
                 }
 
@@ -1914,6 +1986,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
                         free(mtcur->mnt_opts);
         }
 
+ //ret:
         if (ENABLE_FEATURE_CLEAN_UP)
                 endmntent(fstab);
         if (ENABLE_FEATURE_CLEAN_UP) {
diff --git a/util-linux/umount.c b/util-linux/umount.c
index 901c9094f..5b22bfacc 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -73,9 +73,9 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
         } else {
                 while (getmntent_r(fp, &me, path, PATH_MAX)) {
                         /* Match fstype if passed */
-                        if (fstype && match_fstype(&me, fstype))
+                        if (!match_fstype(&me, fstype))
                                 continue;
-                        m = xmalloc(sizeof(struct mtab_list));
+                        m = xzalloc(sizeof(*m));
                         m->next = mtl;
                         m->device = xstrdup(me.mnt_fsname);
                         m->dir = xstrdup(me.mnt_dir);