mount: make -f work even without mtab support

(Cristian Ionescu-Idbohrn <cristian.ionescu-idbohrn at axis.com>)

4 files changed, 46 insertions, 21 deletions

diff --git a/include/usage.h b/include/usage.h
index 59e57f3a0..04ef1822e 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2449,8 +2449,10 @@ USE_FEATURE_BRCTL_FANCY("\n" \
        "Mount a filesystem. Filesystem autodetection requires /proc be mounted." \
        "\n\nOptions:\n" \
        "        -a              Mount all filesystems in fstab\n" \
+        USE_FEATURE_MOUNT_FAKE( \
+       "        -f              "USE_FEATURE_MTAB_SUPPORT("Update /etc/mtab, but ")"don't mount\n" \
+        ) \
         USE_FEATURE_MTAB_SUPPORT( \
-       "        -f              Update /etc/mtab, but don't mount\n" \
        "        -n              Don't update /etc/mtab\n" \
         ) \
        "        -r              Read-only mount\n" \
diff --git a/scripts/defconfig b/scripts/defconfig
index 31a172c56..87bc6bd7e 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -478,6 +478,7 @@ CONFIG_MOUNT=y
 # CONFIG_FEATURE_MOUNT_HELPERS is not set
 CONFIG_FEATURE_MOUNT_NFS=y
 CONFIG_FEATURE_MOUNT_CIFS=y
+CONFIG_FEATURE_MOUNT_FAKE=y
 CONFIG_FEATURE_MOUNT_FLAGS=y
 CONFIG_FEATURE_MOUNT_FSTAB=y
 CONFIG_PIVOT_ROOT=y
diff --git a/util-linux/Config.in b/util-linux/Config.in
index d1688e8c9..5a47318fe 100644
--- a/util-linux/Config.in
+++ b/util-linux/Config.in
@@ -386,6 +386,13 @@ config MOUNT
           NFS filesystems.  Most people using BusyBox will also want to enable
           the 'mount' utility.
 
+config FEATURE_MOUNT_FAKE
+        bool "mount -f option"
+        default n
+        depends on MOUNT
+        help
+          Enable support for faking a file system mount.
+
 config FEATURE_MOUNT_HELPERS
         bool "Support mount helpers"
         default n
@@ -542,6 +549,7 @@ config FEATURE_MTAB_SUPPORT
         bool "Support for the old /etc/mtab file"
         default n
         depends on MOUNT || UMOUNT
+        select FEATURE_MOUNT_FAKE
         help
           Historically, Unix systems kept track of the currently mounted
           partitions in the file "/etc/mtab".  These days, the kernel exports
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 5e6c3ba72..dd753235e 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -54,6 +54,35 @@ enum {
         MOUNT_NOAUTO = (1<<29),
         MOUNT_SWAP   = (1<<30),
 };
+
+
+#define OPTION_STR "o:t:rwanfvsi"
+enum {
+        OPT_o = (1 << 0),
+        OPT_t = (1 << 1),
+        OPT_r = (1 << 2),
+        OPT_w = (1 << 3),
+        OPT_a = (1 << 4),
+        OPT_n = (1 << 5),
+        OPT_f = (1 << 6),
+        OPT_v = (1 << 7),
+        OPT_s = (1 << 8),
+        OPT_i = (1 << 9),
+};
+
+#if ENABLE_FEATURE_MTAB_SUPPORT
+#define useMtab (!(option_mask32 & OPT_n))
+#else
+#define useMtab 0
+#endif
+
+#if ENABLE_FEATURE_MOUNT_FAKE
+#define fakeIt (option_mask32 & OPT_f)
+#else
+#define fakeIt 0
+#endif
+
+
 // TODO: more "user" flag compatibility.
 // "user" option (from mount manpage):
 // Only the user that mounted a filesystem can unmount it again.
@@ -288,14 +317,6 @@ static void delete_block_backed_filesystems(void)
 void delete_block_backed_filesystems(void);
 #endif
 
-#if ENABLE_FEATURE_MTAB_SUPPORT
-static int useMtab = 1;
-static int fakeIt;
-#else
-#define useMtab 0
-#define fakeIt 0
-#endif
-
 // Perform actual mount of specific filesystem at specific location.
 // NB: mp->xxx fields may be trashed on exit
 static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
@@ -346,7 +367,7 @@ static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
         /* If the mount was successful, and we're maintaining an old-style
          * mtab file by hand, add the new entry to it now. */
  mtab:
-        if (ENABLE_FEATURE_MTAB_SUPPORT && useMtab && !rc && !(vfsflags & MS_REMOUNT)) {
+        if (useMtab && !rc && !(vfsflags & MS_REMOUNT)) {
                 char *fsname;
                 FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
                 const char *option_str = mount_option_str;
@@ -1657,17 +1678,10 @@ int mount_main(int argc, char **argv)
 
         // Parse remaining options
 
-        opt = getopt32(argv, "o:t:rwanfvsi", &opt_o, &fstype);
-        if (opt & 0x1) append_mount_options(&cmdopts, opt_o); // -o
-        //if (opt & 0x2) // -t
-        if (opt & 0x4) append_mount_options(&cmdopts, "ro"); // -r
-        if (opt & 0x8) append_mount_options(&cmdopts, "rw"); // -w
-        //if (opt & 0x10) // -a
-        if (opt & 0x20) USE_FEATURE_MTAB_SUPPORT(useMtab = 0); // -n
-        if (opt & 0x40) USE_FEATURE_MTAB_SUPPORT(fakeIt = 1); // -f
-        //if (opt & 0x80) // -v: verbose (ignore)
-        //if (opt & 0x100) // -s: sloppy (ignore)
-        //if (opt & 0x200) // -i: don't call mount.<fstype> (ignore)
+        opt = getopt32(argv, OPTION_STR, &opt_o, &fstype);
+        if (opt & OPT_o) append_mount_options(&cmdopts, opt_o); // -o
+        if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
+        if (opt & OPT_w) append_mount_options(&cmdopts, "rw"); // -w
         argv += optind;
         argc -= optind;