mdev: ignore events with "$SUBSYSTEM" == "firmware" && "$ACTION" == "remove"

function                                             old     new   delta
mdev_main                                            665     676     +11

1 files changed, 21 insertions, 10 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index b7b311aaa..6eaa66bf4 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -436,11 +436,10 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                         ACTION_RECURSE | ACTION_FOLLOWLINKS,
                         fileAction, dirAction, temp, 0);
         } else {
+                char *fw;
                 char *seq;
                 char *action;
                 char *env_path;
-                char seqbuf[sizeof(int)*3 + 2];
-                int seqlen = seqlen; /* for compiler */
 
                 /* Hotplug:
                  * env ACTION=... DEVPATH=... [SEQNUM=...] mdev
@@ -451,14 +450,23 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 env_path = getenv("DEVPATH");
                 if (!action || !env_path)
                         bb_show_usage();
+                fw = getenv("FIRMWARE");
 
+                /* If it exists, does /dev/mdev.seq match $SEQNUM?
+                 * If it does not match, earlier mdev is running
+                 * in parallel, and we need to wait */
                 seq = getenv("SEQNUM");
                 if (seq) {
-                        int timeout = 2000 / 32;
+                        int timeout = 2000 / 32; /* 2000 msec */
                         do {
+                                int seqlen;
+                                char seqbuf[sizeof(int)*3 + 2];
+
                                 seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
-                                if (seqlen < 0)
+                                if (seqlen < 0) {
+                                        seq = NULL;
                                         break;
+                                }
                                 seqbuf[seqlen] = '\0';
                                 if (seqbuf[0] == '\n' /* seed file? */
                                  || strcmp(seq, seqbuf) == 0 /* correct idx? */
@@ -470,19 +478,22 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 }
 
                 snprintf(temp, PATH_MAX, "/sys%s", env_path);
-                if (!strcmp(action, "remove"))
-                        make_device(temp, 1);
-                else if (!strcmp(action, "add")) {
+                if (strcmp(action, "remove") == 0) {
+                        /* Ignoring "remove firmware". It was reported
+                         * to happen and to cause erroneous deletion
+                         * of device nodes. */
+                        if (!fw)
+                                make_device(temp, 1);
+                }
+                else if (strcmp(action, "add") == 0) {
                         make_device(temp, 0);
-
                         if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
-                                char *fw = getenv("FIRMWARE");
                                 if (fw)
                                         load_firmware(fw, temp);
                         }
                 }
 
-                if (seq && seqlen >= 0) {
+                if (seq) {
                         xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
                 }
         }