1 files changed, 22 insertions, 7 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 884e5de33..ca4b91510 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -947,7 +947,7 @@ static void open_mdev_log(const char *seq, unsigned my_pid)
  * Active mdev pokes us with SIGCHLD to check the new file.
  */
 static int
-wait_for_seqfile(const char *seq)
+wait_for_seqfile(unsigned expected_seq)
 {
         /* We time out after 2 sec */
         static const struct timespec ts = { 0, 32*1000*1000 };
@@ -962,12 +962,14 @@ wait_for_seqfile(const char *seq)
 
         for (;;) {
                 int seqlen;
-                char seqbuf[sizeof(int)*3 + 2];
+                char seqbuf[sizeof(long)*3 + 2];
+                unsigned seqbufnum;
 
                 if (seq_fd < 0) {
                         seq_fd = open("mdev.seq", O_RDWR);
                         if (seq_fd < 0)
                                 break;
+                        close_on_exec_on(seq_fd);
                 }
                 seqlen = pread(seq_fd, seqbuf, sizeof(seqbuf) - 1, 0);
                 if (seqlen < 0) {
@@ -978,17 +980,25 @@ wait_for_seqfile(const char *seq)
                 seqbuf[seqlen] = '\0';
                 if (seqbuf[0] == '\n' || seqbuf[0] == '\0') {
                         /* seed file: write out seq ASAP */
-                        xwrite_str(seq_fd, seq);
+                        xwrite_str(seq_fd, utoa(expected_seq));
                         xlseek(seq_fd, 0, SEEK_SET);
                         dbg2("first seq written");
                         break;
                 }
-                if (strcmp(seq, seqbuf) == 0) {
+                seqbufnum = atoll(seqbuf);
+                if (seqbufnum == expected_seq) {
                         /* correct idx */
                         break;
                 }
+                if (seqbufnum > expected_seq) {
+                        /* a later mdev runs already (this was seen by users to happen) */
+                        /* do not overwrite seqfile on exit */
+                        close(seq_fd);
+                        seq_fd = -1;
+                        break;
+                }
                 if (do_once) {
-                        dbg2("%s mdev.seq='%s', need '%s'", curtime(), seqbuf, seq);
+                        dbg2("%s mdev.seq='%s', need '%u'", curtime(), seqbuf, expected_seq);
                         do_once = 0;
                 }
                 if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
@@ -1079,6 +1089,7 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 char *env_devname;
                 char *env_devpath;
                 unsigned my_pid;
+                unsigned seqnum = seqnum; /* for compiler */
                 int seq_fd;
                 smalluint op;
 
@@ -1100,7 +1111,11 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 my_pid = getpid();
                 open_mdev_log(seq, my_pid);
 
-                seq_fd = seq ? wait_for_seqfile(seq) : -1;
+                seq_fd = -1;
+                if (seq) {
+                        seqnum = atoll(seq);
+                        seq_fd = wait_for_seqfile(seqnum);
+                }
 
                 dbg1("%s "
                         "ACTION:%s SUBSYSTEM:%s DEVNAME:%s DEVPATH:%s"
@@ -1128,7 +1143,7 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
 
                 dbg1("%s exiting", curtime());
                 if (seq_fd >= 0) {
-                        xwrite_str(seq_fd, utoa(xatou(seq) + 1));
+                        xwrite_str(seq_fd, utoa(seqnum + 1));
                         signal_mdevs(my_pid);
                 }
         }