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

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

1 files changed, 15 insertions, 14 deletions

diff --git a/util-linux/mount.c b/util-linux/mount.c
index f1da30fac..220a4e67c 100644
--- 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)