mkfs_vfat: do not generate same volume_id when run in rapid succession

function                                             old     new   delta
mkfs_vfat_main                                      1502    1523     +21

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

1 files changed, 3 insertions, 2 deletions

diff --git a/util-linux/mkfs_vfat.c b/util-linux/mkfs_vfat.c
index 821371953..d2db78e1d 100644
--- a/util-linux/mkfs_vfat.c
+++ b/util-linux/mkfs_vfat.c
@@ -267,8 +267,9 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 
         // cache device name
         device_name = argv[0];
-        // default volume ID = creation time
-        volume_id = time(NULL);
+        // default volume ID: somewhat random (not crypto-strong)
+        // (mix in pid to avoid same IDs when run in rapid succession)
+        volume_id = time(NULL) ^ getpid();
         // truncate to exactly 11 chars, pad with spaces
         sprintf(volume_label11, "%-11.11s", arg_volume_label);