[PATCH] udevd: split up message receiving an queueing

[elogind.git] / udevd.c

diff --git a/udevd.c b/udevd.c
index c6642f4359b890d1cb63cdf75ddff4739df52fab..0049e696f1930a6029974b9c9c3ff8ec9ee2792f 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -101,9 +101,14 @@ static void msg_queue_insert(struct hotplug_msg *msg)
        struct hotplug_msg *loop_msg;
        struct sysinfo info;
 
-       /* sort message by sequence number into list. events
-        * will tend to come in order, so scan the list backwards
-        */
+       if (msg->seqnum == 0) {
+               dbg("no SEQNUM, move straight to the exec queue");
+               list_add(&msg->list, &exec_list);
+               run_exec_q = 1;
+               return;
+       }
+
+       /* sort message by sequence number into list */
        list_for_each_entry_reverse(loop_msg, &msg_list, list)
                if (loop_msg->seqnum < msg->seqnum)
                        break;
@@ -151,34 +156,51 @@ static void udev_run(struct hotplug_msg *msg)
        }
 }
 
-/* returns still running task for the same event sequence */
+static int compare_devpath(const char *running, const char *waiting)
+{
+       int i;
+
+       for (i = 0; i < DEVPATH_SIZE; i++) {
+               /* identical device event found */
+               if (running[i] == '\0' && waiting[i] == '\0')
+                       return 1;
+
+               /* parent device event found */
+               if (running[i] == '\0' && waiting[i] == '/')
+                       return 2;
+
+               /* child device event found */
+               if (running[i] == '/' && waiting[i] == '\0')
+                       return 3;
+
+               /* no matching event */
+               if (running[i] != waiting[i])
+                       break;
+       }
+
+       return 0;
+}
+
+/* returns still running task for the same device, its parent or its physical device */
 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
        struct hotplug_msg *loop_msg;
-       int i;
+
+       if (msg->devpath == NULL)
+               return NULL;
 
        list_for_each_entry(loop_msg, &running_list, list) {
-               if (loop_msg->devpath == NULL || msg->devpath == NULL)
+               if (loop_msg->devpath == NULL)
                        continue;
 
-               /* is a parent or child device event still running */
-               for (i = 0; i < DEVPATH_SIZE; i++) {
-                       if (loop_msg->devpath[i] == '\0' || msg->devpath[i] == '\0')
-                               return loop_msg;
-
-                       if (loop_msg->devpath[i] != msg->devpath[i])
-                               break;
-               }
+               /* return running parent/child device event */
+               if (compare_devpath(loop_msg->devpath, msg->devpath) != 0)
+                       return loop_msg;
 
-               /* is the physical device event still running on an add sequence */
+               /* return running physical device event */
                if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
-                       for (i = 0; i < DEVPATH_SIZE; i++) {
-                               if (loop_msg->devpath[i] == '\0' || msg->physdevpath[i] == '\0')
-                                       return loop_msg;
-
-                               if (loop_msg->devpath[i] != msg->physdevpath[i])
-                                       break;
-                       }
+                       if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0)
+                               return loop_msg;
        }
 
        return NULL;
@@ -262,8 +284,8 @@ recheck:
        }
 }
 
-/* receive the msg, do some basic sanity checks, and queue it */
-static void handle_udevsend_msg(int sock)
+/* receive the udevsend message and do some sanity checks */
+static struct hotplug_msg *get_udevsend_msg(void)
 {
        static struct udevsend_msg usend_msg;
        struct hotplug_msg *msg;
@@ -287,33 +309,36 @@ static void handle_udevsend_msg(int sock)
        smsg.msg_control = cred_msg;
        smsg.msg_controllen = sizeof(cred_msg);
 
-       size = recvmsg(sock, &smsg, 0);
+       size = recvmsg(udevsendsock, &smsg, 0);
        if (size <  0) {
                if (errno != EINTR)
-                       dbg("unable to receive message");
-               return;
+                       dbg("unable to receive udevsend message");
+               return NULL;
        }
        cmsg = CMSG_FIRSTHDR(&smsg);
        cred = (struct ucred *) CMSG_DATA(cmsg);
 
        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
                dbg("no sender credentials received, message ignored");
-               goto exit;
+               return NULL;
        }
 
        if (cred->uid != 0) {
                dbg("sender uid=%i, message ignored", cred->uid);
-               goto exit;
+               return NULL;
        }
 
        if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
                dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
-               goto exit;
+               return NULL;
        }
 
        envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
        dbg("envbuf_size=%i", envbuf_size);
        msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
+       if (msg == NULL)
+               return NULL;
+
        memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
 
        /* copy environment buffer and reconstruct envp */
@@ -348,16 +373,7 @@ static void handle_udevsend_msg(int sock)
        msg->envp[i++] = "UDEVD_EVENT=1";
        msg->envp[i] = NULL;
 
-       /* if no seqnum is given, we move straight to exec queue */
-       if (msg->seqnum == 0) {
-               list_add(&msg->list, &exec_list);
-               run_exec_q = 1;
-       } else {
-               msg_queue_insert(msg);
-       }
-
-exit:
-       return;
+       return msg;
 }
 
 static void asmlinkage sig_handler(int signum)
@@ -552,6 +568,8 @@ int main(int argc, char *argv[], char *envp[])
        FD_SET(pipefds[0], &readfds);
        maxsockplus = udevsendsock+1;
        while (1) {
+               struct hotplug_msg *msg;
+
                fd_set workreadfds = readfds;
                retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
 
@@ -561,8 +579,11 @@ int main(int argc, char *argv[], char *envp[])
                        continue;
                }
 
-               if (FD_ISSET(udevsendsock, &workreadfds))
-                       handle_udevsend_msg(udevsendsock);
+               if (FD_ISSET(udevsendsock, &workreadfds)) {
+                       msg = get_udevsend_msg();
+                       if (msg)
+                               msg_queue_insert(msg);
+               }
 
                if (FD_ISSET(pipefds[0], &workreadfds))
                        user_sighandler();