chiark / gitweb /
[PATCH] udevd - cleanup and better timeout handling
authorkay.sievers@vrfy.org <kay.sievers@vrfy.org>
Sun, 1 Feb 2004 17:12:36 +0000 (09:12 -0800)
committerGreg KH <gregkh@suse.de>
Wed, 27 Apr 2005 04:13:20 +0000 (21:13 -0700)
On Thu, Jan 29, 2004 at 04:55:11PM +0100, Kay Sievers wrote:
> On Thu, Jan 29, 2004 at 02:56:25AM +0100, Kay Sievers wrote:
> > On Wed, Jan 28, 2004 at 10:47:36PM +0100, Kay Sievers wrote:
> > > Oh, couldn't resist to try threads.
> > > It's a multithreaded udevd that communicates through a localhost socket.
> > > The message includes a magic with the udev version, so we don't accept
> > > older udevsend's.
> > >
> > > No need for locking, cause we can't bind two sockets on the same address.
> > > The daemon tries to connect and if it fails it starts the daemon.
> > >
> > > We create a thread for every incoming connection, handle over the socket,
> > > sort the messages in the global message queue and exit the thread.
> > > Huh, that was easy with threads :)
> > >
> > > With the addition of a message we wakeup the queue manager thread and
> > > handle timeouts or move the message to the global exec list. This wakes
> > > up the exec list manager who looks if a process is already running for this
> > > device path.
> > > If yes, the exec is delayed otherwise we create a thread that execs udev.
> > > n the background. With the return of udev we free the message and wakeup
> > > the exec list manager to look if something is pending.
> > >
> > > It is just a quick shot, cause I couldn't solve the problems with fork an
> > > scheduling and I wanted to see if I'm to stupid  :)
> > > But if anybody with a better idea or more experience with I/O scheduling
> > > we may go another way. The remaining problem is that klibc doesn't support
> > > threads.
> > >
> > > By now, we don't exec anything, it's just a sleep 3 for every exec,
> > > but you can see the queue management by watching syslog and do:
> > >
> > >   DEVPATH=/abc ACTION=add SEQNUM=0 ./udevsend /abc
>
> Next version, switched to unix domain sockets.

Next cleaned up version. Hey, nobody wants to try it :)

Works for me, It's funny if I connect/disconnect my 4in1-usb-flash-reader
every two seconds. The 2.6 usb rocks! I can connect/diconnect a hub with 3
devices plugged in every second and don't run into any problem but a _very_
big udevd queue.

Makefile
test/udevd_test.sh
udevd.c
udevd.h
udevsend.c

index 8af6ecf..d953218 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -255,7 +255,7 @@ $(HELPER): udevinfo.o $(OBJS) $(HEADERS)
        $(STRIPCMD) $@
 
 $(DAEMON): udevd.h udevd.o udevd.o logging.o
-       $(LD) $(LDFLAGS) -o $@ $(CRT0) udevd.o logging.o $(LIB_OBJS) $(ARCH_LIB_OBJS)
+       $(LD) $(LDFLAGS) -lpthread -o $@ $(CRT0) udevd.o logging.o $(LIB_OBJS) $(ARCH_LIB_OBJS)
        $(STRIPCMD) $@
 
 $(SENDER): udevd.h udevsend.o udevd.o logging.o
index 9469808..506e886 100644 (file)
@@ -1,9 +1,7 @@
-#!/bin/bash
+#!/bin/sh
 
-# kill daemon, first event will start it again
-killall udevd
-
-# 3 x connect/disconnect sequence of sda/sdb/sdc
+# add/rem/add/rem/add sequence of sda/sdb/sdc
+# a few days longer and the socket of my usb-flash-reader is gone :)
 
 export SEQNUM=3
 export ACTION=add
diff --git a/udevd.c b/udevd.c
index 22c3865..22fb4d3 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -1,9 +1,6 @@
 /*
- * udevd.c
+ * udevd.c - hotplug event serializer
  *
- * Userspace devfs
- *
- * Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
  *
  *
@@ -24,9 +21,7 @@
 
 #include <stddef.h>
 #include <sys/types.h>
-#include <sys/ipc.h>
 #include <sys/wait.h>
-#include <sys/msg.h>
 #include <signal.h>
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
 #include <time.h>
 #include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <pthread.h>
 
 #include "list.h"
 #include "udev.h"
 #include "logging.h"
 
 
-#define BUFFER_SIZE                    1024
-
-static int running_remove_queue(pid_t pid);
-static int msg_exec(struct hotplug_msg *msg);
-
-static int expect_seqnum = 0;
-static int lock_file = -1;
-static char *lock_filename = ".udevd_lock";
+static pthread_mutex_t  msg_lock;
+static pthread_mutex_t  msg_active_lock;
+static pthread_cond_t msg_active;
+static pthread_mutex_t  exec_lock;
+static pthread_mutex_t  exec_active_lock;
+static pthread_cond_t exec_active;
+static pthread_mutex_t  running_lock;
+static pthread_attr_t thr_attr;
+static int expected_seqnum = 0;
 
 LIST_HEAD(msg_list);
+LIST_HEAD(exec_list);
 LIST_HEAD(running_list);
-LIST_HEAD(delayed_list);
 
-static void sig_handler(int signum)
-{
-       pid_t pid;
-
-       dbg("caught signal %d", signum);
-       switch (signum) {
-       case SIGALRM:
-               dbg("event timeout reached");
-               break;
-       case SIGCHLD:
-               /* catch signals from exiting childs */
-               while ( (pid = waitpid(-1, NULL, WNOHANG)) > 0) {
-                       dbg("exec finished, pid %d", pid);
-                       running_remove_queue(pid);
-               }
-               break;
-       case SIGINT:
-       case SIGTERM:
-               if (lock_file >= 0) {
-                       close(lock_file);
-                       unlink(lock_filename);
-               }
-               exit(20 + signum);
-               break;
-       default:
-               dbg("unhandled signal");
-       }
-}
 
-static void set_timeout(int seconds)
+static void msg_dump_queue(void)
 {
-       alarm(seconds);
-       dbg("set timeout in %d seconds", seconds);
-}
+       struct hotplug_msg *msg;
 
-static int running_moveto_queue(struct hotplug_msg *msg)
-{
-       dbg("move sequence %d [%d] to running queue '%s'",
-           msg->seqnum, msg->pid, msg->devpath);
-       list_move_tail(&msg->list, &running_list);
-       return 0;
+       list_for_each_entry(msg, &msg_list, list)
+               dbg("sequence %d in queue", msg->seqnum);
 }
 
-static int running_remove_queue(pid_t  pid)
+static void msg_dump(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *child;
-       struct hotplug_msg *tmp_child;
-
-       list_for_each_entry_safe(child, tmp_child, &running_list, list)
-               if (child->pid == pid) {
-                       list_del_init(&child->list);
-                       free(child);
-                       return 0;
-               }
-       return -EINVAL;
+       dbg("sequence %d, '%s', '%s', '%s'",
+           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
 }
 
-static pid_t running_getpid_by_devpath(struct hotplug_msg *msg)
+/* allocates a new message */
+static struct hotplug_msg *msg_create(void)
 {
-       struct hotplug_msg *child;
-       struct hotplug_msg *tmp_child;
+       struct hotplug_msg *new_msg;
 
-       list_for_each_entry_safe(child, tmp_child, &running_list, list)
-               if (strncmp(child->devpath, msg->devpath, sizeof(child->devpath)) == 0)
-                       return child->pid;
-       return 0;
+       new_msg = malloc(sizeof(struct hotplug_msg));
+       if (new_msg == NULL) {
+               dbg("error malloc");
+               return NULL;
+       }
+       memset(new_msg, 0x00, sizeof(struct hotplug_msg));
+       return new_msg;
 }
 
-static void delayed_dump_queue(void)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *child;
+       struct hotplug_msg *loop_msg;
 
-       list_for_each_entry(child, &delayed_list, list)
-               dbg("event for '%s' in queue", child->devpath);
-}
+       /* sort message by sequence number into list*/
+       list_for_each_entry(loop_msg, &msg_list, list)
+               if (loop_msg->seqnum > msg->seqnum)
+                       break;
+       list_add_tail(&msg->list, &loop_msg->list);
+       dbg("queued message seq %d", msg->seqnum);
 
-static int delayed_moveto_queue(struct hotplug_msg *msg)
-{
-       dbg("move event to delayed queue '%s'", msg->devpath);
-       list_move_tail(&msg->list, &delayed_list);
-       return 0;
-}
+       /* store timestamp of queuing */
+       msg->queue_time = time(NULL);
 
-static void delayed_check_queue(void)
-{
-       struct hotplug_msg *delayed_child;
-       struct hotplug_msg *running_child;
-       struct hotplug_msg *tmp_child;
-
-       /* see if we have delayed exec's that can run now */
-       list_for_each_entry_safe(delayed_child, tmp_child, &delayed_list, list)
-               list_for_each_entry_safe(running_child, tmp_child, &running_list, list)
-                       if (strncmp(delayed_child->devpath, running_child->devpath,
-                           sizeof(running_child->devpath)) == 0) {
-                               dbg("delayed exec for '%s' can run now", delayed_child->devpath);
-                               msg_exec(delayed_child);
-                       }
-}
+       /* signal queue activity to manager */
+       pthread_mutex_lock(&msg_active_lock);
+       pthread_cond_signal(&msg_active);
+       pthread_mutex_unlock(&msg_active_lock);
 
-static void msg_dump(struct hotplug_msg *msg)
-{
-       dbg("sequence %d, '%s', '%s', '%s'",
-           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
+       return ;
 }
 
-static int msg_exec(struct hotplug_msg *msg)
+/* forks event and removes event from run queue when finished */
+static void *run_threads(void * parm)
 {
        pid_t pid;
+       struct hotplug_msg *msg;
 
-       msg_dump(msg);
-
+       msg = parm;
        setenv("ACTION", msg->action, 1);
        setenv("DEVPATH", msg->devpath, 1);
 
-       /* delay exec, if we already have a udev working on the same devpath */
-       pid = running_getpid_by_devpath(msg);
-       if (pid != 0) {
-               dbg("delay exec of sequence %d, [%d] already working on '%s'",
-                   msg->seqnum, pid, msg->devpath);
-               delayed_moveto_queue(msg);
-       }
-
        pid = fork();
        switch (pid) {
        case 0:
@@ -188,135 +128,206 @@ static int msg_exec(struct hotplug_msg *msg)
                break;
        case -1:
                dbg("fork of child failed");
-               return -1;
+               goto exit;
        default:
-               /* exec in background, get the SIGCHLD with the sig handler */
-               msg->pid = pid;
-               running_moveto_queue(msg);
-               break;
+               /* wait for exit of child */
+               dbg("==> exec seq %d [%d] working at '%s'",
+                   msg->seqnum, pid, msg->devpath);
+               wait(NULL);
+               dbg("<== exec seq %d came back", msg->seqnum);
        }
-       return 0;
+
+exit:
+       /* remove event from run list */
+       pthread_mutex_lock(&running_lock);
+       list_del_init(&msg->list);
+       pthread_mutex_unlock(&running_lock);
+
+       free(msg);
+
+       /* signal queue activity to exec manager */
+       pthread_mutex_lock(&exec_active_lock);
+       pthread_cond_signal(&exec_active);
+       pthread_mutex_unlock(&exec_active_lock);
+
+       pthread_exit(0);
 }
 
-static void msg_dump_queue(void)
+/* returns already running task with devpath */
+static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *msg;
+       struct hotplug_msg *loop_msg;
+       struct hotplug_msg *tmp_msg;
 
-       list_for_each_entry(msg, &msg_list, list)
-               dbg("sequence %d in queue", msg->seqnum);
+       list_for_each_entry_safe(loop_msg, tmp_msg, &running_list, list)
+               if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
+                       return loop_msg;
+       return NULL;
 }
 
-static void msg_check_queue(void)
+/* queue management executes the events and delays events for the same devpath */
+static void *exec_queue_manager(void * parm)
 {
+       struct hotplug_msg *loop_msg;
+       struct hotplug_msg *tmp_msg;
        struct hotplug_msg *msg;
+       pthread_t run_tid;
+
+       while (1) {
+               pthread_mutex_lock(&exec_lock);
+               list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
+                       msg = running_with_devpath(loop_msg);
+                       if (msg == NULL) {
+                               /* move event to run list */
+                               pthread_mutex_lock(&running_lock);
+                               list_move_tail(&loop_msg->list, &running_list);
+                               pthread_mutex_unlock(&running_lock);
+
+                               pthread_create(&run_tid, &thr_attr, run_threads, (void *) loop_msg);
+
+                               dbg("moved seq %d to running list", loop_msg->seqnum);
+                       } else {
+                               dbg("delay seq %d, cause seq %d already working on '%s'",
+                                   loop_msg->seqnum, msg->seqnum, msg->devpath);
+                       }
+               }
+               pthread_mutex_unlock(&exec_lock);
+
+               /* wait for activation, new events or childs coming back */
+               pthread_mutex_lock(&exec_active_lock);
+               pthread_cond_wait(&exec_active, &exec_active_lock);
+               pthread_mutex_unlock(&exec_active_lock);
+       }
+}
+
+/* move message from incoming to exec queue */
+static void msg_move_exec(struct list_head *head)
+{
+       list_move_tail(head, &exec_list);
+       /* signal queue activity to manager */
+       pthread_mutex_lock(&exec_active_lock);
+       pthread_cond_signal(&exec_active);
+       pthread_mutex_unlock(&exec_active_lock);
+}
+
+/* queue management thread handles the timeouts and dispatches the events */
+static void *msg_queue_manager(void * parm)
+{
+       struct hotplug_msg *loop_msg;
        struct hotplug_msg *tmp_msg;
-       time_t msg_age;
+       time_t msg_age = 0;
+       struct timespec tv;
 
+       while (1) {
+               dbg("msg queue manager, next expected is %d", expected_seqnum);
+               pthread_mutex_lock(&msg_lock);
+               pthread_mutex_lock(&exec_lock);
 recheck:
-       /* dispatch events until one is missing */
-       list_for_each_entry_safe(msg, tmp_msg, &msg_list, list) {
-               if (msg->seqnum != expect_seqnum)
-                       break;
-               msg_exec(msg);
-               expect_seqnum++;
-       }
+               list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
+                       /* move event with expected sequence to the exec list */
+                       if (loop_msg->seqnum == expected_seqnum) {
+                               msg_move_exec(&loop_msg->list);
+                               expected_seqnum++;
+                               dbg("moved seq %d to exec, next expected is %d",
+                                   loop_msg->seqnum, expected_seqnum);
+                               continue;
+                       }
 
-       /* recalculate next timeout */
-       if (list_empty(&msg_list) == 0) {
-               msg_age = time(NULL) - msg->queue_time;
-               if (msg_age > EVENT_TIMEOUT_SEC-1) {
-                       info("event %d, age %li seconds, skip event %d-%d",
-                            msg->seqnum, msg_age, expect_seqnum, msg->seqnum-1);
-                       expect_seqnum = msg->seqnum;
-                       goto recheck;
+                       /* move event with expired timeout to the exec list */
+                       msg_age = time(NULL) - loop_msg->queue_time;
+                       if (msg_age > EVENT_TIMEOUT_SEC-1) {
+                               msg_move_exec(&loop_msg->list);
+                               expected_seqnum = loop_msg->seqnum+1;
+                               dbg("moved seq %d to exec, reset next expected to %d",
+                                   loop_msg->seqnum, expected_seqnum);
+                               goto recheck;
+                       } else {
+                               break;
+                       }
                }
 
-               /* the first sequence gets its own timeout */
-               if (expect_seqnum == 0) {
-                       msg_age = EVENT_TIMEOUT_SEC - FIRST_EVENT_TIMEOUT_SEC;
-                       expect_seqnum = 1;
-               }
+               msg_dump_queue();
+               pthread_mutex_unlock(&exec_lock);
+               pthread_mutex_unlock(&msg_lock);
 
-               set_timeout(EVENT_TIMEOUT_SEC - msg_age);
-               return;
+               /* wait until queue gets active or next message timeout expires */
+               pthread_mutex_lock(&msg_active_lock);
+
+               if (list_empty(&msg_list) == 0) {
+                       tv.tv_sec = time(NULL) + EVENT_TIMEOUT_SEC - msg_age;
+                       tv.tv_nsec = 0;
+                       dbg("next event expires in %li seconds",
+                           EVENT_TIMEOUT_SEC - msg_age);
+                       pthread_cond_timedwait(&msg_active, &msg_active_lock, &tv);
+               } else {
+                       pthread_cond_wait(&msg_active, &msg_active_lock);
+               }
+               pthread_mutex_unlock(&msg_active_lock);
        }
 }
 
-static int msg_add_queue(struct hotplug_msg *msg)
+/* every connect creates a thread which gets the msg, queues it and exits */
+static void *client_threads(void * parm)
 {
-       struct hotplug_msg *new_msg;
-       struct hotplug_msg *tmp_msg;
+       int sock;
+       struct hotplug_msg *msg;
+       int retval;
 
-       new_msg = malloc(sizeof(*new_msg));
-       if (new_msg == NULL) {
-               dbg("error malloc");
-               return -ENOMEM;
+       sock = (int) parm;
+
+       msg = msg_create();
+       if (msg == NULL) {
+               dbg("unable to store message");
+               goto exit;
        }
-       memcpy(new_msg, msg, sizeof(*new_msg));
 
-       /* store timestamp of queuing */
-       new_msg->queue_time = time(NULL);
+       retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
+       if (retval <  0) {
+               dbg("unable to receive message");
+               goto exit;
+       }
 
-       /* sort message by sequence number into list*/
-       list_for_each_entry(tmp_msg, &msg_list, list)
-               if (tmp_msg->seqnum > new_msg->seqnum)
-                       break;
-       list_add_tail(&new_msg->list, &tmp_msg->list);
+       if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+               dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+               goto exit;
+       }
 
-       return 0;
+       pthread_mutex_lock(&msg_lock);
+       msg_queue_insert(msg);
+       pthread_mutex_unlock(&msg_lock);
+
+exit:
+       close(sock);
+       pthread_exit(0);
 }
 
-static void work(void)
+static void sig_handler(int signum)
 {
-       struct hotplug_msg *msg;
-       int msgid;
-       key_t key;
-       char buf[BUFFER_SIZE];
-       int ret;
-
-       key = ftok(UDEVD_BIN, IPC_KEY_ID);
-       msg = (struct hotplug_msg *) buf;
-       msgid = msgget(key, IPC_CREAT);
-       if (msgid == -1) {
-               dbg("open message queue error");
-               exit(1);
-       }
-       while (1) {
-               ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0);
-               if (ret != -1) {
-                       dbg("received sequence %d, expected sequence %d", msg->seqnum, expect_seqnum);
-                       if (msg->seqnum >= expect_seqnum) {
-                               msg_add_queue(msg);
-                               msg_dump_queue();
-                               msg_check_queue();
-                               continue;
-                       }
-                       dbg("too late for event with sequence %d, event skipped ", msg->seqnum);
-               } else {
-                       if (errno == EINTR) {
-                               msg_check_queue();
-                               msg_dump_queue();
-                               delayed_check_queue();
-                               delayed_dump_queue();
-                               continue;
-                       }
-                       dbg("ipc message receive error '%s'", strerror(errno));
-               }
+       switch (signum) {
+               case SIGINT:
+               case SIGTERM:
+                       unlink(UDEVD_LOCK);
+                       unlink(UDEVD_SOCKET);
+                       exit(20 + signum);
+                       break;
+               default:
+                       dbg("unhandled signal");
        }
 }
 
 static int one_and_only(void)
 {
-       char string[100];
-
-       lock_file = open(lock_filename, O_RDWR | O_CREAT, 0x640);
+       char string[50];
+       int lock_file;
 
        /* see if we can open */
+       lock_file = open(UDEVD_LOCK, O_RDWR | O_CREAT, 0x640);
        if (lock_file < 0)
                return -1;
-       
+
        /* see if we can lock */
        if (lockf(lock_file, F_TLOCK, 0) < 0) {
+               dbg("file is already locked, exit");
                close(lock_file);
                return -1;
        }
@@ -329,16 +340,73 @@ static int one_and_only(void)
 
 int main(int argc, char *argv[])
 {
+       int ssock;
+       int csock;
+       struct sockaddr_un saddr;
+       struct sockaddr_un caddr;
+       socklen_t clen;
+       pthread_t cli_tid;
+       pthread_t mgr_msg_tid;
+       pthread_t mgr_exec_tid;
+       int retval;
+
        /* only let one version of the daemon run at any one time */
        if (one_and_only() != 0)
                exit(0);
 
-       /* set up signal handler */
        signal(SIGINT, sig_handler);
        signal(SIGTERM, sig_handler);
-       signal(SIGALRM, sig_handler);
-       signal(SIGCHLD, sig_handler);
 
-       work();
-       exit(0);
+       memset(&saddr, 0x00, sizeof(saddr));
+       saddr.sun_family = AF_LOCAL;
+       strcpy(saddr.sun_path, UDEVD_SOCKET);
+
+       unlink(UDEVD_SOCKET);
+       ssock = socket(AF_LOCAL, SOCK_STREAM, 0);
+       if (ssock == -1) {
+               dbg("error getting socket");
+               exit(1);
+       }
+
+       retval = bind(ssock, &saddr, sizeof(saddr));
+       if (retval < 0) {
+               dbg("bind failed\n");
+               goto exit;
+       }
+
+       retval = listen(ssock, SOMAXCONN);
+       if (retval < 0) {
+               dbg("listen failed\n");
+               goto exit;
+       }
+
+       pthread_mutex_init(&msg_lock, NULL);
+       pthread_mutex_init(&msg_active_lock, NULL);
+       pthread_mutex_init(&exec_lock, NULL);
+       pthread_mutex_init(&exec_active_lock, NULL);
+       pthread_mutex_init(&running_lock, NULL);
+
+       /* set default attributes for created threads */
+       pthread_attr_init(&thr_attr);
+       pthread_attr_setdetachstate(&thr_attr, PTHREAD_CREATE_DETACHED);
+
+       /* init queue management */
+       pthread_create(&mgr_msg_tid, &thr_attr, msg_queue_manager, NULL);
+       pthread_create(&mgr_exec_tid, &thr_attr, exec_queue_manager, NULL);
+
+       clen = sizeof(caddr);
+       /* main loop */
+       while (1) {
+               csock = accept(ssock, &caddr, &clen);
+               if (csock < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       dbg("client accept failed\n");
+               }
+               pthread_create(&cli_tid, &thr_attr, client_threads, (void *) csock);
+       }
+exit:
+       close(ssock);
+       unlink(UDEVD_SOCKET);
+       exit(1);
 }
diff --git a/udevd.h b/udevd.h
index 4bccd4b..e24bc28 100644 (file)
--- a/udevd.h
+++ b/udevd.h
@@ -4,6 +4,7 @@
  * Userspace devfs
  *
  * Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
  *
  *
  *     This program is free software; you can redistribute it and/or modify it
 
 #include "list.h"
 
-#define FIRST_EVENT_TIMEOUT_SEC                1
-#define EVENT_TIMEOUT_SEC              5
-#define UDEVSEND_RETRY_COUNT           50 /* x 10 millisec */
-
-#define IPC_KEY_ID                     1
-#define HOTPLUGMSGTYPE                 44
+/*
+ * FIXME: udev_root is post compile configurable and may also be
+ * mounted over at any time and /var/run/ and /tmp/ is unusable,
+ * cause it's cleaned at system startup, long _after_ udevd is
+ * already running. Should we use udev_init_config()?
+ */
 
+#define UDEV_MAGIC                     "udev_" UDEV_VERSION
+#define EVENT_TIMEOUT_SEC              5
+#define UDEVSEND_CONNECT_RETRY         20 /* x 100 millisec */
+#define UDEVD_SOCKET                   UDEV_ROOT ".udevd.socket"
+#define UDEVD_LOCK                     UDEV_ROOT ".udevd.pid"
 
 struct hotplug_msg {
-       long mtype;
+       char magic[20];
        struct list_head list;
        pid_t pid;
        int seqnum;
index f92ee2b..6ffd68c 100644 (file)
 #include <unistd.h>
 #include <time.h>
 #include <wait.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 
 #include "udev.h"
 #include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"
 
+
 static inline char *get_action(void)
 {
        char *action;
@@ -66,7 +69,7 @@ static int build_hotplugmsg(struct hotplug_msg *msg, char *action,
                            char *devpath, char *subsystem, int seqnum)
 {
        memset(msg, 0x00, sizeof(*msg));
-       msg->mtype = HOTPLUGMSGTYPE;
+       strfieldcpy(msg->magic, UDEV_MAGIC);
        msg->seqnum = seqnum;
        strncpy(msg->action, action, 8);
        strncpy(msg->devpath, devpath, 128);
@@ -108,12 +111,8 @@ static int start_daemon(void)
        return 0;
 }
 
-
 int main(int argc, char* argv[])
 {
-       int msgid;
-       key_t key;
-       struct msqid_ds msg_queue;
        struct hotplug_msg message;
        char *action;
        char *devpath;
@@ -124,6 +123,8 @@ int main(int argc, char* argv[])
        int size;
        int loop;
        struct timespec tspec;
+       int sock;
+       struct sockaddr_un saddr;
 
        subsystem = argv[1];
        if (subsystem == NULL) {
@@ -150,41 +151,58 @@ int main(int argc, char* argv[])
        }
        seq = atoi(seqnum);
 
-       /* create ipc message queue or get id of our existing one */
-       key = ftok(UDEVD_BIN, IPC_KEY_ID);
-       dbg("using ipc queue 0x%0x", key);
-       size =  build_hotplugmsg(&message, action, devpath, subsystem, seq);
-       msgid = msgget(key, IPC_CREAT);
-       if (msgid == -1) {
-               dbg("error open ipc queue");
+       sock = socket(AF_LOCAL, SOCK_STREAM, 0);
+       if (sock == -1) {
+               dbg("error getting socket");
                goto exit;
        }
 
-       /* send ipc message to the daemon */
-       retval = msgsnd(msgid, &message, size, 0);
-       if (retval == -1) {
-               dbg("error sending ipc message");
-               goto exit;
+       memset(&saddr, 0x00, sizeof(saddr));
+       saddr.sun_family = AF_LOCAL;
+       strcpy(saddr.sun_path, UDEVD_SOCKET);
+
+       /* try to connect, if it fails start daemon */
+       retval = connect(sock, &saddr, sizeof(saddr));
+       if (retval != -1) {
+               goto send;
+       } else {
+               dbg("connect failed, try starting daemon...");
+               retval = start_daemon();
+               if (retval == 0) {
+                       dbg("daemon started");
+               } else {
+                       dbg("error starting daemon");
+                       goto exit;
+               }
        }
 
-       /* get state of ipc queue */
+       /* try to connect while daemon to starts */
        tspec.tv_sec = 0;
-       tspec.tv_nsec = 10000000;  /* 10 millisec */
-       loop = UDEVSEND_RETRY_COUNT;
+       tspec.tv_nsec = 100000000;  /* 100 millisec */
+       loop = UDEVSEND_CONNECT_RETRY;
        while (loop--) {
-               retval = msgctl(msgid, IPC_STAT, &msg_queue);
-               if (retval == -1) {
-                       dbg("error getting info on ipc queue");
-                       goto exit;
-               }
-               if (msg_queue.msg_qnum == 0)
-                       goto exit;
+               retval = connect(sock, &saddr, sizeof(saddr));
+               if (retval != -1)
+                       goto send;
+               else
+                       dbg("retry to connect %d",
+                           UDEVSEND_CONNECT_RETRY - loop);
                nanosleep(&tspec, NULL);
        }
+       dbg("error connecting to daemon, start daemon failed");
+       goto exit;
 
-       info("message is still in the ipc queue, starting daemon...");
-       retval = start_daemon();
+send:
+       size = build_hotplugmsg(&message, action, devpath, subsystem, seq);
+       retval = send(sock, &message, size, 0);
+       if (retval == -1) {
+               dbg("error sending message");
+               close (sock);
+               goto exit;
+       }
+       close (sock);
+       return 0;
 
 exit:
-       return retval;
+       return 1;
 }