mount: set up RO loop device if mount -o ro. Closes 4784

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/util-linux/mount.c b/util-linux/mount.c
index f1da30faccade2805cc98315b3262df684258b7c..220a4e67c745d58584f5dc44d227d72f3a74c8a5 100644 (file)
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -450,9 +450,9 @@ static void append_mount_options(char **oldopts, const char *newopts)
 
 // Use the mount_options list to parse options into flags.
 // Also update list of unrecognized options if unrecognized != NULL
-static long parse_mount_options(char *options, char **unrecognized)
+static unsigned long parse_mount_options(char *options, char **unrecognized)
 {
-       long flags = MS_SILENT;
+       unsigned long flags = MS_SILENT;
 
        // Loop through options
        for (;;) {
@@ -466,7 +466,7 @@ static long parse_mount_options(char *options, char **unrecognized)
                // Find this option in mount_options
                for (i = 0; i < ARRAY_SIZE(mount_options); i++) {
                        if (strcasecmp(option_str, options) == 0) {
-                               long fl = mount_options[i];
+                               unsigned long fl = mount_options[i];
                                if (fl < 0)
                                        flags &= fl;
                                else
@@ -548,7 +548,7 @@ void delete_block_backed_filesystems(void);
 
 // 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, long vfsflags, char *filteropts)
+static int mount_it_now(struct mntent *mp, unsigned long vfsflags, char *filteropts)
 {
        int rc = 0;
 
@@ -1080,7 +1080,7 @@ static void error_msg_rpc(const char *msg)
 }
 
 /* NB: mp->xxx fields may be trashed on exit */
-static NOINLINE int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
+static NOINLINE int nfsmount(struct mntent *mp, unsigned long vfsflags, char *filteropts)
 {
        CLIENT *mclient;
        char *hostname;
@@ -1711,7 +1711,7 @@ static NOINLINE int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
  * For older kernels, you must build busybox with ENABLE_FEATURE_MOUNT_NFS.
  * (However, note that then you lose any chances that NFS over IPv6 would work).
  */
-static int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
+static int nfsmount(struct mntent *mp, unsigned long vfsflags, char *filteropts)
 {
        len_and_sockaddr *lsa;
        char *opts;
@@ -1753,7 +1753,7 @@ static int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
 static int singlemount(struct mntent *mp, int ignore_busy)
 {
        int rc = -1;
-       long vfsflags;
+       unsigned long vfsflags;
        char *loopFile = NULL, *filteropts = NULL;
        llist_t *fl = NULL;
        struct stat st;
@@ -1854,7 +1854,7 @@ static int singlemount(struct mntent *mp, int ignore_busy)
                if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
                        loopFile = bb_simplify_path(mp->mnt_fsname);
                        mp->mnt_fsname = NULL; // will receive malloced loop dev name
-                       if (set_loop(&mp->mnt_fsname, loopFile, 0, /*ro:*/ 0) < 0) {
+                       if (set_loop(&mp->mnt_fsname, loopFile, 0, /*ro:*/ (vfsflags & MS_RDONLY)) < 0) {
                                if (errno == EPERM || errno == EACCES)
                                        bb_error_msg(bb_msg_perm_denied_are_you_root);
                                else
@@ -1992,6 +1992,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
        FILE *fstab;
        int i, j;
        int rc = EXIT_SUCCESS;
+       unsigned long cmdopt_flags;
        unsigned opt;
        struct mntent mtpair[2], *mtcur = mtpair;
        IF_NOT_DESKTOP(const int nonroot = 0;)
@@ -2066,16 +2067,16 @@ 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, NULL); // FIXME: should be "long", not "int"
-       if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
+       cmdopt_flags = parse_mount_options(cmdopts, NULL);
+       if (nonroot && (cmdopt_flags & ~MS_SILENT)) // Non-root users cannot specify flags
                bb_error_msg_and_die(bb_msg_you_must_be_root);
 
        // If we have a shared subtree flag, don't worry about fstab or mtab.
        if (ENABLE_FEATURE_MOUNT_FLAGS
-        && (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+        && (cmdopt_flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
        ) {
                // verbose_mount(source, target, type, flags, data)
-               rc = verbose_mount("", argv[0], "", i, "");
+               rc = verbose_mount("", argv[0], "", cmdopt_flags, "");
                if (rc)
                        bb_simple_perror_msg_and_die(argv[0]);
                return rc;
@@ -2083,7 +2084,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
 
        // Open either fstab or mtab
        fstabname = "/etc/fstab";
-       if (i & MS_REMOUNT) {
+       if (cmdopt_flags & MS_REMOUNT) {
                // WARNING. I am not sure this matches util-linux's
                // behavior. It's possible util-linux does not
                // take -o opts from mtab (takes only mount source).
@@ -2182,7 +2183,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
        // End of fstab/mtab is reached.
        // Were we looking for something specific?
        if (argv[0]) { // yes
-               long l;
+               unsigned long l;
 
                // If we didn't find anything, complain
                if (!mtcur->mnt_fsname)