X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=24cf9c9a7cf8c5a491c63483fff09f4a91455b70;hp=6af265a3898b811a07a8d08a915698beda679902;hb=872344c41094f636fd667b9e619f8f219d814605;hpb=90c210eb6bfc2ae294202fffb080315f3c47a57b

diff --git a/udevd.c b/udevd.c
index 6af265a38..24cf9c9a7 100644
--- 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>
  *
  *
@@ -22,263 +19,411 @@
  *
  */
 
+#include <pthread.h>
+#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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 
+#include "list.h"
 #include "udev.h"
+#include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"
 
-#define BUFFER_SIZE		1024
-#define TIMEOUT_SECONDS		10
 
-static void reset_timer(void);
-static void reset_queue(void);
+unsigned char logname[42];
+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);
 
-static int expect_seqnum = 0;
-static int timeout_value = TIMEOUT_SECONDS;
-static int timeout = 0;
-static struct hotplug_msg *head = NULL;
-static char exec_program[100];
 
-
-static void sig_handler(int signum)
+static void msg_dump_queue(void)
 {
-	dbg("caught signal %d", signum);
-	switch (signum) {
-		case SIGHUP:
-			dbg("reset requested, all waiting events killed");
-			reset_timer();
-			reset_queue();
-			timeout = 0;
-			expect_seqnum = 0;
-			break;
+	struct hotplug_msg *msg;
 
-		case SIGINT:
-		case SIGTERM:
-		case SIGKILL:
-			exit(20 + signum);
-			break;
-
-		default:
-			dbg("unhandled signal");
-	}
+	list_for_each_entry(msg, &msg_list, list)
+		dbg("sequence %d in queue", msg->seqnum);
 }
 
-static void sig_alarmhandler(int signum)
+static void msg_dump(struct hotplug_msg *msg)
 {
-	dbg("caught signal %d", signum);
-	switch (signum) {
-	case SIGALRM:
-		timeout = 1;
-		dbg("event timeout reached");
-		break;
-
-	default:
-		dbg("unhandled signal");
-	}
+	dbg("sequence %d, '%s', '%s', '%s'",
+	    msg->seqnum, msg->action, msg->devpath, msg->subsystem);
 }
 
-static void dump_queue(void)
+static struct hotplug_msg *msg_create(void)
 {
-	struct hotplug_msg *p;
-	p = head;
+	struct hotplug_msg *new_msg;
 
-	dbg("next expected sequence is %d", expect_seqnum);
-	while(p) {
-		dbg("sequence %d in queue", p->seqnum);
-		p=p->next;
+	new_msg = malloc(sizeof(struct hotplug_msg));
+	if (new_msg == NULL) {
+		dbg("error malloc");
+		return NULL;
 	}
+	return new_msg;
 }
 
-static void dump_msg(struct hotplug_msg *pmsg)
+static void msg_delete(struct hotplug_msg *msg)
 {
-	dbg("sequence %d, '%s', '%s', '%s'",
-	    pmsg->seqnum, pmsg->action, pmsg->devpath, pmsg->subsystem);
+	if (msg != NULL)
+		free(msg);
 }
 
-static int dispatch_msg(struct hotplug_msg *pmsg)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
 {
-	pid_t pid;
-	char *argv[3];
-	int retval;
-	extern char **environ;
+	struct hotplug_msg *loop_msg;
 
-	dump_msg(pmsg);
-	dbg("exec '%s'", exec_program);
+	/* 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);
+
+	/* store timestamp of queuing */
+	msg->queue_time = time(NULL);
 
-	setenv("ACTION", pmsg->action, 1);
-	setenv("DEVPATH", pmsg->devpath, 1);
+	/* signal queue activity to manager */
+	pthread_mutex_lock(&msg_active_lock);
+	pthread_cond_signal(&msg_active);
+	pthread_mutex_unlock(&msg_active_lock);
+
+	return ;
+}
+
+/* forks event and removes event from run queue when finished */
+static void *run_threads(void * parm)
+{
+	pid_t pid;
+	struct hotplug_msg *msg;
 
-	argv[0] = exec_program;
-	argv[1] = pmsg->subsystem;
-	argv[2] = NULL;
+	msg = parm;
+	setenv("ACTION", msg->action, 1);
+	setenv("DEVPATH", msg->devpath, 1);
 
 	pid = fork();
 	switch (pid) {
 	case 0:
-		retval = execve(argv[0], argv, environ);
-		if (retval != 0) {
-			dbg("child execve failed");
-			exit(1);
-		}
+		/* child */
+		execl(UDEV_BIN, "udev", msg->subsystem, NULL);
+		dbg("exec of child failed");
+		exit(1);
 		break;
 	case -1:
-		dbg("fork failed");
-		return -1;
+		dbg("fork of child failed");
+		goto exit;
 	default:
-		wait(0);
-		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);
+
+	msg_delete(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 reset_timer(void)
+/* returns already running task with devpath */
+static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
-	alarm(0);
+	struct hotplug_msg *loop_msg;
+	struct hotplug_msg *tmp_msg;
+
+	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 set_timer(void)
+/* queue management executes the events and delays events for the same devpath */
+static void *exec_queue_manager(void * parm)
 {
-	signal(SIGALRM, sig_alarmhandler);
-	alarm(timeout_value);
+	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);
+	}
 }
 
-static void reset_queue(void)
+static void exec_queue_activate(void)
 {
-	struct hotplug_msg *p;
-	p = head;
+	pthread_mutex_lock(&exec_active_lock);
+	pthread_cond_signal(&exec_active);
+	pthread_mutex_unlock(&exec_active_lock);
+}
 
-	while(head) {
-		p = head;
-		head = head->next;
-		free(p);
-	}
+/* move message from incoming to exec queue */
+static void msg_move_exec(struct list_head *head)
+{
+	list_move_tail(head, &exec_list);
+	exec_queue_activate();
 }
 
-static void check_queue(void)
+/* queue management thread handles the timeouts and dispatches the events */
+static void *msg_queue_manager(void * parm)
 {
-	struct hotplug_msg *p;
-	p = head;
-
-	dump_queue();
-	while(head && head->seqnum == expect_seqnum) {
-		dispatch_msg(head);
-		expect_seqnum++;
-		p = head;
-		head = head->next;
-		free(p);
+	struct hotplug_msg *loop_msg;
+	struct hotplug_msg *tmp_msg;
+	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:
+		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;
+			}
+
+			/* 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;
+			}
+		}
+
+		msg_dump_queue();
+		pthread_mutex_unlock(&exec_lock);
+		pthread_mutex_unlock(&msg_lock);
+
+		/* 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);
 	}
-	if (head != NULL)
-		set_timer();
-	else
-		reset_timer();
 }
 
-static void add_queue(struct hotplug_msg *pmsg)
+/* every connect creates a thread which gets the msg, queues it and exits */
+static void *client_threads(void * parm)
 {
-	struct hotplug_msg *pnewmsg;
-	struct hotplug_msg *p;
-	struct hotplug_msg *p1;
-
-	p = head;
-	p1 = NULL;
-	pnewmsg = malloc(sizeof(struct hotplug_msg));
-	*pnewmsg = *pmsg;
-	pnewmsg->next = NULL;
-	while(p && pmsg->seqnum > p->seqnum) {
-		p1 = p;
-		p = p->next;
+	int sock;
+	struct hotplug_msg *msg;
+	int retval;
+
+	sock = (int) parm;
+
+	msg = msg_create();
+	if (msg == NULL) {
+		dbg("unable to store message");
+		goto exit;
+	}
+
+	retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
+	if (retval <  0) {
+		dbg("unable to receive message");
+		goto exit;
 	}
-	pnewmsg->next = p;
-	if (p1 == NULL) {
-		head = pnewmsg;
+
+	if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+		dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+		msg_delete(msg);
+		goto exit;
+	}
+
+	/* if no seqnum is given, we move straight to exec queue */
+	if (msg->seqnum == 0) {
+		pthread_mutex_lock(&exec_lock);
+		list_add(&msg->list, &exec_list);
+		exec_queue_activate();
+		pthread_mutex_unlock(&exec_lock);
 	} else {
-		p1->next = pnewmsg;
+		pthread_mutex_lock(&msg_lock);
+		msg_queue_insert(msg);
+		pthread_mutex_unlock(&msg_lock);
 	}
-	dump_queue();
+
+exit:
+	close(sock);
+	pthread_exit(0);
 }
 
-static int process_queue(void)
+static void sig_handler(int signum)
 {
-	int msgid;
-	key_t key;
-	struct hotplug_msg *pmsg;
-	char buf[BUFFER_SIZE];
-	int ret;
-
-	key = ftok(DEFAULT_EXEC_PROGRAM, IPC_KEY_ID);
-	pmsg = (struct hotplug_msg *) buf;
-	msgid = msgget(key, IPC_CREAT);
-	if (msgid == -1) {
-		dbg("open message queue error");
-		goto exit;
+	switch (signum) {
+		case SIGINT:
+		case SIGTERM:
+			unlink(UDEVD_LOCK);
+			exit(20 + signum);
+			break;
+		default:
+			dbg("unhandled signal");
 	}
-	while (1) {
-		ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0);
-		if (ret != -1) {
-			dbg("current sequence %d, expected sequence %d", pmsg->seqnum, expect_seqnum);
-
-			/* init expected sequence with value from first call */
-			if (expect_seqnum == 0) {
-				expect_seqnum = pmsg->seqnum;
-				dbg("init next expected sequence number to %d", expect_seqnum);
-			}
+}
 
-			if (pmsg->seqnum > expect_seqnum) {
-				add_queue(pmsg);
-				set_timer();
-			} else {
-				if (pmsg->seqnum == expect_seqnum) {
-					dispatch_msg(pmsg);
-					expect_seqnum++;
-					check_queue();
-				} else {
-					dbg("timeout event for unexpected sequence number %d", pmsg->seqnum);
-				}
-			}
-		} else
-			if (errno == EINTR) {
-				if (head != NULL) {
-					/* timeout, skip all missing, proceed with next queued event */
-					dbg("timeout reached, skip events %d - %d", expect_seqnum, head->seqnum-1);
-					expect_seqnum = head->seqnum;
-				}
-				check_queue();
-				timeout = 0;
-			} else {
-				dbg("ipc message receive error '%s'", strerror(errno));
-			}
+static int one_and_only(void)
+{
+	char string[50];
+	int lock_file;
+
+	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;
 	}
+
+	snprintf(string, sizeof(string), "%d\n", getpid());
+	write(lock_file, string, strlen(string));
+
 	return 0;
-exit:
-	return -1;
 }
 
 int main(int argc, char *argv[])
 {
-	/* get program to exec on events */
-	if (argc == 2)
-		strncpy(exec_program, argv[1], sizeof(exec_program));
-	else
-		strcpy(exec_program, DEFAULT_EXEC_PROGRAM);
+	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;
+
+	init_logging("udevd");
+
+	/* 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(SIGKILL, sig_handler);
-	signal(SIGHUP, sig_handler);
 
+	memset(&saddr, 0x00, sizeof(saddr));
+	saddr.sun_family = AF_LOCAL;
+	/* use abstract namespace for socket path */
+	strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
+
+	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);
+	pthread_attr_setstacksize(&thr_attr, 16 * 1024);
+
+	/* 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 */
-	process_queue();
-	return 0;
+	while (1) {
+		csock = accept(ssock, &caddr, &clen);
+		if (csock < 0) {
+			dbg("client accept failed\n");
+			continue;
+		}
+		pthread_create(&cli_tid, &thr_attr, client_threads, (void *) csock);
+	}
+exit:
+	close(ssock);
+	exit(1);
 }