add /etc/.extroot-uuid support

Signed-off-by: John Crispin <blogic@openwrt.org>

diff --git a/block.c b/block.c
index 1a303e64c3835a414d32733e97b0ed183e758c56..fd8d21efd24f862acf2e4068f640b65822628a08 100644 (file)
--- a/block.c
+++ b/block.c
@@ -449,6 +449,50 @@ static int find_block_mtd(char *name, char *part, int plen)
        return 0;
 }
 
+static int check_extroot(char *path)
+{
+       struct blkid_struct_probe *pr = NULL;
+       char fs[32];
+
+       if (find_block_mtd("rootfs", fs, sizeof(fs)))
+               return -1;
+
+       list_for_each_entry(pr, &devices, list) {
+               if (!strcmp(pr->dev, fs)) {
+                       struct stat s;
+                       FILE *fp = NULL;
+                       char tag[32];
+                       char uuid[32] = { 0 };
+
+                       snprintf(tag, sizeof(tag), "%s/etc/.extroot-uuid", path);
+                       if (stat(tag, &s)) {
+                               fp = fopen(tag, "w+");
+                               if (!fp) {
+                                       fprintf(stderr, "extroot: failed to write uuid tag file\n");
+                                       /* return 0 to continue boot regardless of error */
+                                       return 0;
+                               }
+                               fputs(pr->uuid, fp);
+                               fclose(fp);
+                               return 0;
+                       }
+
+                       fp = fopen(tag, "r");
+                       if (!fp) {
+                               fprintf(stderr, "extroot: failed to open uuid tag file\n");
+                               return -1;
+                       }
+
+                       fgets(uuid, sizeof(uuid), fp);
+                       fclose(fp);
+                       if (!strcmp(uuid, pr->uuid))
+                               return 0;
+                       fprintf(stderr, "extroot: uuid tag does not match rom uuid\n");
+               }
+       }
+       return -1;
+}
+
 static int mount_extroot(char *path, char *cfg)
 {
         struct blkid_struct_probe *pr;
@@ -467,9 +511,14 @@ static int mount_extroot(char *path, char *cfg)
                mkdir_p(path);
                err = mount(pr->dev, path, pr->id->name, 0, (m->options) ? (m->options) : (""));
 
-               if (err)
+               if (err) {
                        fprintf(stderr, "mounting %s (%s) as %s failed (%d) - %s\n",
                                        pr->dev, pr->id->name, path, err, strerror(err));
+               } else {
+                       err = check_extroot(path);
+                       if (err)
+                               umount(path);
+               }
        }
 
        return err;