mount: fix "duplicate mount options in mtab" bug

1 files changed, 21 insertions, 3 deletions

diff --git a/util-linux/mount.c b/util-linux/mount.c
index 57d2d0430..430ec9bac 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -102,9 +102,27 @@ struct {
 static void append_mount_options(char **oldopts, char *newopts)
 {
         if (*oldopts && **oldopts) {
-                char *temp = xasprintf("%s,%s",*oldopts,newopts);
-                free(*oldopts);
-                *oldopts = temp;
+                /* do not insert options which are already there */
+                while (newopts[0]) {
+                        char *p;
+                        int len = strlen(newopts);
+                        p = strchr(newopts, ',');
+                        if (p) len = p - newopts;
+                        p = *oldopts;
+                        while (1) {
+                                if (!strncmp(p,newopts,len) && (p[len]==',' || p[len]==0))
+                                        goto skip;
+                                p = strchr(p,',');
+                                if(!p) break;
+                                p++;
+                        }
+                        p = xasprintf("%s,%.*s", *oldopts, len, newopts);
+                        free(*oldopts);
+                        *oldopts = p;
+skip:
+                        newopts += len;
+                        while (newopts[0] == ',') newopts++;
+                }
         } else {
                 if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
                 *oldopts = xstrdup(newopts);