commit 4f0c3de1bf0b6755ea5b5c9c6ae1db9651784794
author Rob Landley <rob@landley.net> Sun Sep 28 18:22:34 2014 -0500
committer Rob Landley <rob@landley.net> Sun Sep 28 18:22:34 2014 -0500
tree 4a8aa7be3de0eae83f714a59233c361984291f0a
parent 679a21d674cf487992c0ccabc8666c417e59d390

Fix two mount bugs: 1) Don't skip a filesystem type when setting up loopback mount, 2) Don't stop checking filesystem types due to EBUSY, it may mean already mounted by another filesystem type you haven't tried yet.

toys/lsb/mount.c

diff --git a/toys/lsb/mount.c b/toys/lsb/mount.c
index 28db97d..01f5c32 100644
--- a/toys/lsb/mount.c
+++ b/toys/lsb/mount.c
@@ -72,6 +72,7 @@
 // TODO what if you --bind mount a block device somewhere (file, dir, dev)
 // TODO "touch servername; mount -t cifs servername path"
 // TODO mount -o remount a user mount
+// TODO mount image.img sub (auto-loopback) then umount image.img
 
 // Strip flags out of comma separated list of options, return flags,.
 static long flag_opts(char *new, long flags, char **more)
@@ -136,6 +137,7 @@
 {
   FILE *fp = 0;
   int rc = EINVAL;
+  char *buf = 0;
 
   if (toys.optflags & FLAG_f) return;
 
@@ -167,10 +169,8 @@
     toys.exitval |= xrun((char *[]){"swapon", "--", dev, 0});
 
   for (;;) {
-    char *buf = 0;
-
     // If type wasn't specified, try all of them in order.
-    if (fp) {
+    if (fp && !buf) {
       size_t i;
 
       if (getline(&buf, &i, fp)<0) break;
@@ -178,6 +178,8 @@
       // skip nodev devices
       if (!isspace(*type)) {
         free(buf);
+        buf = 0;
+
         continue;
       }
       // trim whitespace
@@ -193,9 +195,6 @@
       fprintf(stderr, "'%s' is read-only", dev);
       flags |= MS_RDONLY;
     }
-    free(buf);
-
-    if (!rc) break;
 
     // Trying to autodetect loop mounts like bind mounts above (file on dir)
     // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if
@@ -209,9 +208,7 @@
     // Solution: try the mount, let the kernel tell us it wanted a block
     // device, then do the loopback setup and retry the mount.
 
-    if (fp && errno == EINVAL) continue;
-
-    if (errno == ENOTBLK) {
+    if (rc && errno == ENOTBLK) {
       char *losetup[] = {"losetup", "-fs", dev, 0};
       int pipe, len;
       pid_t pid;
@@ -226,8 +223,18 @@
         dev = toybuf;
 
         continue;
-      } else error_msg("losetup failed %d", rc);
-    } else perror_msg("'%s'->'%s'", dev, dir);
+      }
+      error_msg("losetup failed %d", rc);
+
+      break;
+    }
+
+    free(buf);
+    buf = 0;
+    if (!rc) break;
+    if (fp && (errno == EINVAL || errno == EBUSY)) continue;
+
+    perror_msg("'%s'->'%s'", dev, dir);
 
     break;
   }