X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=2cd3622ce011a5a04630ff8d05595dbd6d53fc81;hp=811f62243eb98473d6691624dadcb2dfe67b235e;hb=92ebb398ed004348d5f92a242f323fb25dc7d6e5;hpb=e5a5b54ab675988febeaa9cd831e21e675d5947b

diff --git a/udevd.c b/udevd.c
index 811f62243..2cd3622ce 100644
--- a/udevd.c
+++ b/udevd.c
@@ -1,7 +1,7 @@
 /*
  * udevd.c - hotplug event serializer
  *
- * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
  *
  *
@@ -21,32 +21,40 @@
  */
 
 #include <stddef.h>
-#include <sys/wait.h>
 #include <signal.h>
 #include <unistd.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/select.h>
+#include <sys/wait.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-#include <fcntl.h>
-#include "klibc_fixups.h"
 #include <sys/sysinfo.h>
 #include <sys/stat.h>
 
 #include "list.h"
+#include "udev_libc_wrapper.h"
 #include "udev.h"
-#include "udev_lib.h"
 #include "udev_version.h"
+#include "udev_utils.h"
 #include "udevd.h"
 #include "logging.h"
 
+/* global variables*/
+static int udevsendsock;
+static pid_t sid;
+
 static int pipefds[2];
+static long startup_time;
 static unsigned long long expected_seqnum = 0;
-static volatile int children_waiting;
+static volatile int sigchilds_waiting;
 static volatile int run_msg_q;
 static volatile int sig_flag;
 static int run_exec_q;
@@ -58,11 +66,10 @@ static LIST_HEAD(running_list);
 static void exec_queue_manager(void);
 static void msg_queue_manager(void);
 static void user_sighandler(void);
-static void reap_kids(void);
+static void reap_sigchilds(void);
 char *udev_bin;
 
-#ifdef LOG
-unsigned char logname[LOGNAME_SIZE];
+#ifdef USE_LOG
 void log_message (int level, const char *format, ...)
 {
 	va_list	args;
@@ -82,24 +89,14 @@ static void msg_dump_queue(void)
 #ifdef DEBUG
 	struct hotplug_msg *msg;
 
-	list_for_each_entry(msg, &msg_list, list)
+	list_for_each_entry(msg, &msg_list, node)
 		dbg("sequence %llu in queue", msg->seqnum);
 #endif
 }
 
-static struct hotplug_msg *msg_create(void)
-{
-	struct hotplug_msg *new_msg;
-
-	new_msg = malloc(sizeof(struct hotplug_msg));
-	if (new_msg == NULL)
-		dbg("error malloc");
-	return new_msg;
-}
-
 static void run_queue_delete(struct hotplug_msg *msg)
 {
-	list_del(&msg->list);
+	list_del(&msg->node);
 	free(msg);
 }
 
@@ -109,55 +106,58 @@ 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
-	 */
-	list_for_each_entry_reverse(loop_msg, &msg_list, list)
+	if (msg->seqnum == 0) {
+		dbg("no SEQNUM, move straight to the exec queue");
+		list_add(&msg->node, &exec_list);
+		run_exec_q = 1;
+		return;
+	}
+
+	/* sort message by sequence number into list */
+	list_for_each_entry_reverse(loop_msg, &msg_list, node) {
 		if (loop_msg->seqnum < msg->seqnum)
 			break;
 
+		if (loop_msg->seqnum == msg->seqnum) {
+			dbg("ignoring duplicate message seq %llu", msg->seqnum);
+			return;
+		}
+	}
+
 	/* store timestamp of queuing */
 	sysinfo(&info);
 	msg->queue_time = info.uptime;
 
-	list_add(&msg->list, &loop_msg->list);
+	list_add(&msg->node, &loop_msg->node);
 	dbg("queued message seq %llu", msg->seqnum);
 
 	/* run msg queue manager */
 	run_msg_q = 1;
 
-	return ;
+	return;
 }
 
 /* forks event and removes event from run queue when finished */
 static void udev_run(struct hotplug_msg *msg)
 {
+	char *const argv[] = { "udev", msg->subsystem, NULL };
 	pid_t pid;
-	char action[ACTION_SIZE];
-	char devpath[DEVPATH_SIZE];
-	char seqnum[SEQNUM_SIZE];
-	char *env[] = { action, devpath, seqnum, NULL };
-
-	snprintf(action, ACTION_SIZE-1, "ACTION=%s", msg->action);
-	action[ACTION_SIZE-1] = '\0';
-	snprintf(devpath, DEVPATH_SIZE-1, "DEVPATH=%s", msg->devpath);
-	devpath[DEVPATH_SIZE-1] = '\0';
-	sprintf(seqnum, "SEQNUM=%llu", msg->seqnum);
 
 	pid = fork();
 	switch (pid) {
 	case 0:
 		/* child */
-		execle(udev_bin, "udev", msg->subsystem, NULL, env);
+		close(udevsendsock);
+		logging_close();
+
+		setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
+		execve(udev_bin, argv, msg->envp);
 		dbg("exec of child failed");
-		exit(1);
+		_exit(1);
 		break;
 	case -1:
 		dbg("fork of child failed");
 		run_queue_delete(msg);
-		/* note: we never managed to run, so we had no impact on 
-		 * running_with_devpath(), so don't bother setting run_exec_q
-		 */
 		break;
 	default:
 		/* get SIGCHLD in main loop */
@@ -166,40 +166,191 @@ static void udev_run(struct hotplug_msg *msg)
 	}
 }
 
-/* returns already running task with devpath */
+static int running_processes(void)
+{
+	int f;
+	static char buf[4096];
+	int len;
+	int running;
+	const char *pos;
+
+	f = open("/proc/stat", O_RDONLY);
+	if (f == -1)
+		return -1;
+
+	len = read(f, buf, sizeof(buf));
+	close(f);
+
+	if (len <= 0)
+		return -1;
+	else
+		buf[len] = '\0';
+
+	pos = strstr(buf, "procs_running ");
+	if (pos == NULL)
+		return -1;
+
+	if (sscanf(pos, "procs_running %u", &running) != 1)
+		return -1;
+
+	return running;
+}
+
+/* return the number of process es in our session, count only until limit */
+static int running_processes_in_session(pid_t session, int limit)
+{
+	DIR *dir;
+	struct dirent *dent;
+	int running = 0;
+
+	dir = opendir("/proc");
+	if (!dir)
+		return -1;
+
+	/* read process info from /proc */
+	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+		int f;
+		char procdir[64];
+		char line[256];
+		const char *pos;
+		char state;
+		pid_t ppid, pgrp, sess;
+		int len;
+
+		if (!isdigit(dent->d_name[0]))
+			continue;
+
+		snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
+		procdir[sizeof(procdir)-1] = '\0';
+
+		f = open(procdir, O_RDONLY);
+		if (f == -1)
+			continue;
+
+		len = read(f, line, sizeof(line));
+		close(f);
+
+		if (len <= 0)
+			continue;
+		else
+			line[len] = '\0';
+
+		/* skip ugly program name */
+		pos = strrchr(line, ')') + 2;
+		if (pos == NULL)
+			continue;
+
+		if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
+			continue;
+
+		/* count only processes in our session */
+		if (sess != session)
+			continue;
+
+		/* count only running, no sleeping processes */
+		if (state != 'R')
+			continue;
+
+		running++;
+		if (limit > 0 && running >= limit)
+			break;
+	}
+	closedir(dir);
+
+	return running;
+}
+
+static int compare_devpath(const char *running, const char *waiting)
+{
+	int i;
+
+	for (i = 0; i < PATH_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;
-	list_for_each_entry(loop_msg, &running_list, list)
-		if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
+
+	if (msg->devpath == NULL)
+		return NULL;
+
+	list_for_each_entry(loop_msg, &running_list, node) {
+		if (loop_msg->devpath == NULL)
+			continue;
+
+		/* return running parent/child device event */
+		if (compare_devpath(loop_msg->devpath, msg->devpath) != 0)
 			return loop_msg;
+
+		/* return running physical device event */
+		if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
+			if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0)
+				return loop_msg;
+	}
+
 	return NULL;
 }
 
-/* exec queue management routine executes the events and delays events for the same devpath */
-static void exec_queue_manager()
+/* exec queue management routine executes the events and serializes events in the same sequence */
+static void exec_queue_manager(void)
 {
 	struct hotplug_msg *loop_msg;
 	struct hotplug_msg *tmp_msg;
 	struct hotplug_msg *msg;
+	int running;
+
+	running = running_processes();
+	dbg("%d processes runnning on system", running);
+	if (running < 0)
+		running = THROTTLE_MAX_RUNNING_CHILDS;
+
+	list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
+		/* check running processes in our session and possibly throttle */
+		if (running >= THROTTLE_MAX_RUNNING_CHILDS) {
+			running = running_processes_in_session(sid, THROTTLE_MAX_RUNNING_CHILDS+10);
+			dbg("%d processes running in session", running);
+			if (running >= THROTTLE_MAX_RUNNING_CHILDS) {
+				dbg("delay seq %llu, cause too many processes already running", loop_msg->seqnum);
+				return;
+			}
+		}
 
-	list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
 		msg = running_with_devpath(loop_msg);
 		if (!msg) {
 			/* move event to run list */
-			list_move_tail(&loop_msg->list, &running_list);
+			list_move_tail(&loop_msg->node, &running_list);
 			udev_run(loop_msg);
+			running++;
 			dbg("moved seq %llu to running list", loop_msg->seqnum);
 		} else {
-			dbg("delay seq %llu, cause seq %llu already working on '%s'",
-				loop_msg->seqnum, msg->seqnum, msg->devpath);
+			dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
+			    loop_msg->seqnum, loop_msg->devpath, msg->seqnum, msg->devpath);
 		}
 	}
 }
 
 static void msg_move_exec(struct hotplug_msg *msg)
 {
-	list_move_tail(&msg->list, &exec_list);
+	list_move_tail(&msg->node, &exec_list);
 	run_exec_q = 1;
 	expected_seqnum = msg->seqnum+1;
 	dbg("moved seq %llu to exec, next expected is %llu",
@@ -207,27 +358,36 @@ static void msg_move_exec(struct hotplug_msg *msg)
 }
 
 /* msg queue management routine handles the timeouts and dispatches the events */
-static void msg_queue_manager()
+static void msg_queue_manager(void)
 {
 	struct hotplug_msg *loop_msg;
 	struct hotplug_msg *tmp_msg;
 	struct sysinfo info;
 	long msg_age = 0;
+	static int timeout = EVENT_INIT_TIMEOUT_SEC;
+	static int init = 1;
 
 	dbg("msg queue manager, next expected is %llu", expected_seqnum);
 recheck:
-	list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
+	list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, node) {
 		/* move event with expected sequence to the exec list */
 		if (loop_msg->seqnum == expected_seqnum) {
 			msg_move_exec(loop_msg);
 			continue;
 		}
 
+		/* see if we are in the initialization phase and wait for the very first events */
+		if (init && (info.uptime - startup_time >= INIT_TIME_SEC)) {
+			init = 0;
+			timeout = EVENT_TIMEOUT_SEC;
+			dbg("initialization phase passed, set timeout to %i seconds", EVENT_TIMEOUT_SEC);
+		}
+
 		/* move event with expired timeout to the exec list */
 		sysinfo(&info);
 		msg_age = info.uptime - loop_msg->queue_time;
 		dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
-		if (msg_age > EVENT_TIMEOUT_SEC-1) {
+		if (msg_age >= timeout) {
 			msg_move_exec(loop_msg);
 			goto recheck;
 		} else {
@@ -239,31 +399,30 @@ recheck:
 
 	/* set timeout for remaining queued events */
 	if (list_empty(&msg_list) == 0) {
-		struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
-		dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age);
-		setitimer(ITIMER_REAL, &itv, 0);
+		struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
+		dbg("next event expires in %li seconds", timeout - msg_age);
+		setitimer(ITIMER_REAL, &itv, NULL);
 	}
 }
 
-/* receive the msg, do some basic sanity checks, and queue it */
-static void handle_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;
-	int retval;
+	int bufpos;
+	int i;
+	ssize_t size;
 	struct msghdr smsg;
 	struct cmsghdr *cmsg;
 	struct iovec iov;
 	struct ucred *cred;
 	char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+	int envbuf_size;
 
-	msg = msg_create();
-	if (msg == NULL) {
-		dbg("unable to store message");
-		return;
-	}
-
-	iov.iov_base = msg;
-	iov.iov_len = sizeof(struct hotplug_msg);
+	memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
+	iov.iov_base = &usend_msg;
+	iov.iov_len = sizeof(struct udevsend_msg);
 
 	memset(&smsg, 0x00, sizeof(struct msghdr));
 	smsg.msg_iov = &iov;
@@ -271,42 +430,71 @@ static void handle_msg(int sock)
 	smsg.msg_control = cred_msg;
 	smsg.msg_controllen = sizeof(cred_msg);
 
-	retval = recvmsg(sock, &smsg, 0);
-	if (retval <  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 skip;
+		return NULL;
 	}
 
 	if (cred->uid != 0) {
 		dbg("sender uid=%i, message ignored", cred->uid);
-		goto skip;
+		return NULL;
 	}
 
-	if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
-		dbg("message magic '%s' doesn't match, ignore it", msg->magic);
-		goto skip;
+	if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+		dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
+		return 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);
+	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 */
+	memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
+	bufpos = 0;
+	for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
+		int keylen;
+		char *key;
+
+		key = &msg->envbuf[bufpos];
+		keylen = strlen(key);
+		msg->envp[i] = key;
+		bufpos += keylen + 1;
+		dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
+
+		/* remember some keys for further processing */
+		if (strncmp(key, "ACTION=", 7) == 0)
+			msg->action = &key[7];
+
+		if (strncmp(key, "DEVPATH=", 8) == 0)
+			msg->devpath = &key[8];
+
+		if (strncmp(key, "SUBSYSTEM=", 10) == 0)
+			msg->subsystem = &key[10];
+
+		if (strncmp(key, "SEQNUM=", 7) == 0)
+			msg->seqnum = strtoull(&key[7], NULL, 10);
+
+		if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
+			msg->physdevpath = &key[12];
 	}
-	return;
+	msg->envp[i++] = "UDEVD_EVENT=1";
+	msg->envp[i] = NULL;
 
-skip:
-	free(msg);
-	return;
+	return msg;
 }
 
 static void asmlinkage sig_handler(int signum)
@@ -325,23 +513,18 @@ static void asmlinkage sig_handler(int signum)
 			break;
 		case SIGCHLD:
 			/* set flag, then write to pipe if needed */
-			children_waiting = 1;
+			sigchilds_waiting = 1;
 			goto do_write;
 			break;
-		default:
-			dbg("unhandled signal %d", signum);
-			return;
 	}
-	
+
 do_write:
 	/* if pipe is empty, write to pipe to force select to return
 	 * immediately when it gets called
 	 */
 	if (!sig_flag) {
 		rc = write(pipefds[1],&signum,sizeof(signum));
-		if (rc < 0)
-			dbg("unable to write to pipe");
-		else
+		if (rc >= 0)
 			sig_flag = 1;
 	}
 }
@@ -351,7 +534,7 @@ static void udev_done(int pid)
 	/* find msg associated with pid and delete it */
 	struct hotplug_msg *msg;
 
-	list_for_each_entry(msg, &running_list, list) {
+	list_for_each_entry(msg, &running_list, node) {
 		if (msg->pid == pid) {
 			dbg("<== exec seq %llu came back", msg->seqnum);
 			run_queue_delete(msg);
@@ -366,11 +549,10 @@ static void udev_done(int pid)
 	}
 }
 
-static void reap_kids()
+static void reap_sigchilds(void)
 {
-	/* reap all dead children */
 	while(1) {
-		int pid = waitpid(-1, 0, WNOHANG);
+		int pid = waitpid(-1, NULL, WNOHANG);
 		if ((pid == -1) || (pid == 0))
 			break;
 		udev_done(pid);
@@ -378,13 +560,14 @@ static void reap_kids()
 }
 
 /* just read everything from the pipe and clear the flag,
- * the useful flags were set in the signal handler
+ * the flags was set in the signal handler
  */
-static void user_sighandler()
+static void user_sighandler(void)
 {
 	int sig;
+
 	while(1) {
-		int rc = read(pipefds[0],&sig,sizeof(sig));
+		int rc = read(pipefds[0], &sig, sizeof(sig));
 		if (rc < 0)
 			break;
 
@@ -392,72 +575,124 @@ static void user_sighandler()
 	}
 }
 
-
-int main(int argc, char *argv[])
+static int init_udevsend_socket(void)
 {
-	int ssock, maxsockplus;
 	struct sockaddr_un saddr;
 	socklen_t addrlen;
-	int retval, fd;
-	const int on = 1;
+	const int feature_on = 1;
+	int retval;
+
+	memset(&saddr, 0x00, sizeof(saddr));
+	saddr.sun_family = AF_LOCAL;
+	/* use abstract namespace for socket path */
+	strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
+	addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
+
+	udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
+	if (udevsendsock == -1) {
+		dbg("error getting socket, %s", strerror(errno));
+		return -1;
+	}
+
+	/* the bind takes care of ensuring only one copy running */
+	retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
+	if (retval < 0) {
+		dbg("bind failed, %s", strerror(errno));
+		close(udevsendsock);
+		return -1;
+	}
+
+	/* enable receiving of the sender credentials */
+	setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
+
+	return 0;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+	struct sysinfo info;
+	int maxsockplus;
+	int retval;
+	int fd;
 	struct sigaction act;
 	fd_set readfds;
+	const char *udevd_expected_seqnum;
 
-	init_logging("udevd");
+	logging_init("udevd");
 	dbg("version %s", UDEV_VERSION);
 
 	if (getuid() != 0) {
 		dbg("need to be root, exit");
-		exit(1);
+		goto exit;
 	}
-	/* make sure we are at top of dir */
+
+	/* daemonize on request */
+	if (argc == 2 && strcmp(argv[1], "-d") == 0) {
+		pid_t pid;
+
+		pid = fork();
+		switch (pid) {
+		case 0:
+			dbg("damonized fork running");
+			break;
+		case -1:
+			dbg("fork of daemon failed");
+			goto exit;
+		default:
+			logging_close();
+			exit(0);
+		}
+	}
+
+	/* become session leader */
+	sid = setsid();
+	dbg("our session is %d", sid);
+
+	/* make sure we don't lock any path */
 	chdir("/");
-	umask( umask( 077 ) | 022 );
+	umask(umask(077) | 022);
+
+	/*set a reasonable scheduling priority for the daemon */
+	setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
+
 	/* Set fds to dev/null */
 	fd = open( "/dev/null", O_RDWR );
-	if ( fd < 0 ) {
+	if (fd >= 0)  {
+		dup2(fd, 0);
+		dup2(fd, 1);
+		dup2(fd, 2);
+		if (fd > 2)
+			close(fd);
+	} else
 		dbg("error opening /dev/null %s", strerror(errno));
-		exit(1);
-	}
-	dup2(fd, 0);
-	dup2(fd, 1);
-	dup2(fd, 2);
-	if (fd > 2) 
-		close(fd);
-	/* Get new session id so stray signals don't come our way. */
-	setsid();
 
 	/* setup signal handler pipe */
 	retval = pipe(pipefds);
 	if (retval < 0) {
 		dbg("error getting pipes: %s", strerror(errno));
-		exit(1);
+		goto exit;
 	}
 
 	retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
 	if (retval < 0) {
 		dbg("error fcntl on read pipe: %s", strerror(errno));
-		exit(1);
+		goto exit;
 	}
 	retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
-	if (retval < 0) {
+	if (retval < 0)
 		dbg("error fcntl on read pipe: %s", strerror(errno));
-		exit(1);
-	}
 
 	retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
 	if (retval < 0) {
 		dbg("error fcntl on write pipe: %s", strerror(errno));
-		exit(1);
+		goto exit;
 	}
 	retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
-	if (retval < 0) {
+	if (retval < 0)
 		dbg("error fcntl on write pipe: %s", strerror(errno));
-		exit(1);
-	}
 
-	
 	/* set signal handlers */
+	memset(&act, 0x00, sizeof(struct sigaction));
 	act.sa_handler = (void (*) (int))sig_handler;
 	sigemptyset(&act.sa_mask);
 	act.sa_flags = SA_RESTART;
@@ -466,34 +701,14 @@ int main(int argc, char *argv[])
 	sigaction(SIGALRM, &act, NULL);
 	sigaction(SIGCHLD, &act, NULL);
 
-	memset(&saddr, 0x00, sizeof(saddr));
-	saddr.sun_family = AF_LOCAL;
-	/* use abstract namespace for socket path */
-	strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
-	addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
-
-	ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
-	if (ssock == -1) {
-		dbg("error getting socket, exit");
-		exit(1);
-	}
-
-	set_cloexec_flag(ssock, 1);
+	if (init_udevsend_socket() < 0) {
+		if (errno == EADDRINUSE)
+			dbg("another udevd running, exit");
+		else
+			dbg("error initialising udevsend socket: %s", strerror(errno));
 
-	/* the bind takes care of ensuring only one copy running */
-	retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
-	if (retval < 0) {
-		dbg("bind failed, exit");
 		goto exit;
 	}
-	retval = fcntl(ssock, F_SETFD, FD_CLOEXEC);
-	if (retval < 0) {
-		dbg("error fcntl on ssock: %s", strerror(errno));
-		exit(1);
-	}
-
-	/* enable receiving of the sender credentials */
-	setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 
 	/* possible override of udev binary, used for testing */
 	udev_bin = getenv("UDEV_BIN");
@@ -502,11 +717,24 @@ int main(int argc, char *argv[])
 	else
 		udev_bin = UDEV_BIN;
 
+	/* possible init of expected_seqnum value */
+	udevd_expected_seqnum = getenv("UDEVD_EXPECTED_SEQNUM");
+	if (udevd_expected_seqnum != NULL) {
+		expected_seqnum = strtoull(udevd_expected_seqnum, NULL, 10);
+		dbg("initialize expected_seqnum to %llu", expected_seqnum);
+	}
+
+	/* get current time to provide shorter timeout on startup */
+	sysinfo(&info);
+	startup_time = info.uptime;
+
 	FD_ZERO(&readfds);
-	FD_SET(ssock, &readfds);
+	FD_SET(udevsendsock, &readfds);
 	FD_SET(pipefds[0], &readfds);
-	maxsockplus = ssock+1;
+	maxsockplus = udevsendsock+1;
 	while (1) {
+		struct hotplug_msg *msg;
+
 		fd_set workreadfds = readfds;
 		retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
 
@@ -516,15 +744,18 @@ int main(int argc, char *argv[])
 			continue;
 		}
 
-		if (FD_ISSET(ssock, &workreadfds))
-			handle_msg(ssock);
+		if (FD_ISSET(udevsendsock, &workreadfds)) {
+			msg = get_udevsend_msg();
+			if (msg)
+				msg_queue_insert(msg);
+		}
 
 		if (FD_ISSET(pipefds[0], &workreadfds))
 			user_sighandler();
 
-		if (children_waiting) {
-			children_waiting = 0;
-			reap_kids();
+		if (sigchilds_waiting) {
+			sigchilds_waiting = 0;
+			reap_sigchilds();
 		}
 
 		if (run_msg_q) {
@@ -533,21 +764,18 @@ int main(int argc, char *argv[])
 		}
 
 		if (run_exec_q) {
-			/* this is tricky.  exec_queue_manager() loops over exec_list, and
-			 * calls running_with_devpath(), which loops over running_list. This gives
-			 * O(N*M), which can get *nasty*.  Clean up running_list before
-			 * calling exec_queue_manager().
-			 */
-			if (children_waiting) {
-				children_waiting = 0;
-				reap_kids();
+			 /* clean up running_list before calling exec_queue_manager() */
+			if (sigchilds_waiting) {
+				sigchilds_waiting = 0;
+				reap_sigchilds();
 			}
 
 			run_exec_q = 0;
 			exec_queue_manager();
 		}
 	}
+
 exit:
-	close(ssock);
-	exit(1);
+	logging_close();
+	return 1;
 }