Fix a possible race condition if two processes try to claim the same loop

device at the same time.  We should only CLR_FD if the set status fails,
not if the SET_FD fails.


git-svn-id: svn://busybox.net/trunk/busybox@15509 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 4 insertions, 3 deletions

diff --git a/libbb/loop.c b/libbb/loop.c
index 2f9d02924..e5b21642e 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -118,9 +118,10 @@ int set_loop(char **device, const char *file, int offset)
                         safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
                         loopinfo.lo_offset = offset;
                         /* Associate free loop device with file.  */
-                        if(!ioctl(dfd, LOOP_SET_FD, ffd) &&
-                           !ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
-                        else ioctl(dfd, LOOP_CLR_FD, 0);
+                        if(!ioctl(dfd, LOOP_SET_FD, ffd)) {
+                           if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
+                                else ioctl(dfd, LOOP_CLR_FD, 0);
+                        }
 
                 /* If this block device already set up right, re-use it.
                    (Yes this is racy, but associating two loop devices with the same