X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=81f4474a89b6bc7df5ddd834cff3180d0cb12bdf;hp=26e6b23486b23963fa34cfb09ed102520deded59;hb=6e3e3c3416864eca74cb885f64c453eb531eed63;hpb=a695feaeff0551745e1a397be2daa61b8cd0cc42

diff --git a/udevd.c b/udevd.c
index 26e6b2348..81f4474a8 100644
--- a/udevd.c
+++ b/udevd.c
@@ -1,10 +1,8 @@
 /*
- * 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>
+ * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
  *
  *
  *	This program is free software; you can redistribute it and/or modify it
@@ -23,255 +21,532 @@
  */
 
 #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 <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 "list.h"
 #include "udev.h"
+#include "udev_lib.h"
+#include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"
 
-#define BUFFER_SIZE			1024
+static int pipefds[2];
+static unsigned long long expected_seqnum = 0;
+static volatile int children_waiting;
+static volatile int run_msg_q;
+static volatile int sig_flag;
+static int run_exec_q;
+
+static LIST_HEAD(msg_list);
+static LIST_HEAD(exec_list);
+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);
+char *udev_bin;
+
+#ifdef LOG
+unsigned char logname[LOGNAME_SIZE];
+void log_message (int level, const char *format, ...)
+{
+	va_list	args;
 
-static int expect_seqnum = 0;
-static int lock_file = -1;
-static char *lock_filename = ".udevd_lock";
+	va_start(args, format);
+	vsyslog(level, format, args);
+	va_end(args);
+}
+#endif
 
-LIST_HEAD(msg_list);
+#define msg_dump(msg) \
+	dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \
+	msg->seqnum, msg->action, msg->devpath, msg->subsystem);
 
-static void sig_handler(int signum)
+static void msg_dump_queue(void)
 {
-	dbg("caught signal %d", signum);
-	switch (signum) {
-	case SIGALRM:
-		dbg("event timeout reached");
-		break;
-	case SIGINT:
-	case SIGTERM:
-	case SIGKILL:
-		if (lock_file >= 0) {
-			close(lock_file);
-			unlink(lock_filename);
-		}
-		exit(20 + signum);
-		break;
-	default:
-		dbg("unhandled signal");
-	}
+#ifdef DEBUG
+	struct hotplug_msg *msg;
+
+	list_for_each_entry(msg, &msg_list, list)
+		dbg("sequence %llu in queue", msg->seqnum);
+#endif
 }
 
-static void dump_queue(void)
+static struct hotplug_msg *msg_create(void)
 {
-	struct hotplug_msg *msg;
+	struct hotplug_msg *new_msg;
 
-	list_for_each_entry(msg, &msg_list, list)
-		dbg("sequence %d in queue", msg->seqnum);
+	new_msg = malloc(sizeof(struct hotplug_msg));
+	if (new_msg == NULL)
+		dbg("error malloc");
+	return new_msg;
 }
 
-static void dump_msg(struct hotplug_msg *msg)
+static void run_queue_delete(struct hotplug_msg *msg)
 {
-	dbg("sequence %d, '%s', '%s', '%s'",
-	    msg->seqnum, msg->action, msg->devpath, msg->subsystem);
+	list_del(&msg->list);
+	free(msg);
 }
 
-static int dispatch_msg(struct hotplug_msg *msg)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
 {
-	pid_t pid;
+	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 (loop_msg->seqnum < msg->seqnum)
+			break;
+
+	/* store timestamp of queuing */
+	sysinfo(&info);
+	msg->queue_time = info.uptime;
 
-	dump_msg(msg);
+	list_add(&msg->list, &loop_msg->list);
+	dbg("queued message seq %llu", msg->seqnum);
 
-	setenv("ACTION", msg->action, 1);
-	setenv("DEVPATH", msg->devpath, 1);
+	/* run msg queue manager */
+	run_msg_q = 1;
+
+	return ;
+}
+
+/* forks event and removes event from run queue when finished */
+static void udev_run(struct hotplug_msg *msg)
+{
+	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 */
-		execl(UDEV_EXEC, "udev", msg->subsystem, NULL);
+		execle(udev_bin, "udev", msg->subsystem, NULL, env);
 		dbg("exec of child failed");
 		exit(1);
 		break;
 	case -1:
 		dbg("fork of child failed");
-		return -1;
+		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:
-		wait(NULL);
+		/* get SIGCHLD in main loop */
+		dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
+		msg->pid = pid;
 	}
-	return 0;
 }
 
-static void set_timeout(int seconds)
+/* returns already running task with devpath */
+static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
-	alarm(seconds);
-	dbg("set timeout in %d seconds", seconds);
+	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)
+			return loop_msg;
+	return NULL;
 }
 
-static void check_queue(void)
+/* exec queue management routine executes the events and delays events for the same devpath */
+static void exec_queue_manager()
 {
+	struct hotplug_msg *loop_msg;
+	struct hotplug_msg *tmp_msg;
 	struct hotplug_msg *msg;
+
+	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);
+			udev_run(loop_msg);
+			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);
+		}
+	}
+}
+
+static void msg_move_exec(struct hotplug_msg *msg)
+{
+	list_move_tail(&msg->list, &exec_list);
+	run_exec_q = 1;
+	expected_seqnum = msg->seqnum+1;
+	dbg("moved seq %llu to exec, next expected is %llu",
+		msg->seqnum, expected_seqnum);
+}
+
+/* msg queue management routine handles the timeouts and dispatches the events */
+static void msg_queue_manager()
+{
+	struct hotplug_msg *loop_msg;
 	struct hotplug_msg *tmp_msg;
-	time_t msg_age;
+	struct sysinfo info;
+	long msg_age = 0;
 
+	dbg("msg queue manager, next expected is %llu", expected_seqnum);
 recheck:
-	/* dispatch events until one is missing */
-	list_for_each_entry_safe(msg, tmp_msg, &msg_list, list) {
-		if (msg->seqnum != expect_seqnum)
-			break;
-		dispatch_msg(msg);
-		expect_seqnum++;
-		list_del_init(&msg->list);
-		free(msg);
-	}
+	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);
+			continue;
+		}
 
-	/* recalculate timeout */
-	if (list_empty(&msg_list) == 0) {
-		msg_age = time(NULL) - msg->queue_time;
-		if (msg_age > EVENT_TIMEOUT_SECONDS-1) {
-			info("event %d, age %li seconds, skip event %d-%d",
-			     msg->seqnum, msg_age, expect_seqnum, msg->seqnum-1);
-			expect_seqnum = msg->seqnum;
+		/* 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) {
+			msg_move_exec(loop_msg);
 			goto recheck;
+		} else {
+			break;
 		}
-		set_timeout(EVENT_TIMEOUT_SECONDS - msg_age);
-		return;
 	}
 
-	/* queue is empty */
-	set_timeout(UDEVD_TIMEOUT_SECONDS);
+	msg_dump_queue();
+
+	/* 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);
+	}
 }
 
-static int queue_msg(struct hotplug_msg *msg)
+/* receive the msg, do some basic sanity checks, and queue it */
+static void handle_msg(int sock)
 {
-	struct hotplug_msg *new_msg;
-	struct hotplug_msg *tmp_msg;
+	struct hotplug_msg *msg;
+	int retval;
+	struct msghdr smsg;
+	struct cmsghdr *cmsg;
+	struct iovec iov;
+	struct ucred *cred;
+	char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+
+	msg = msg_create();
+	if (msg == NULL) {
+		dbg("unable to store message");
+		return;
+	}
 
-	new_msg = malloc(sizeof(*new_msg));
-	if (new_msg == NULL) {
-		dbg("error malloc");
-		return -ENOMEM;
+	iov.iov_base = msg;
+	iov.iov_len = sizeof(struct hotplug_msg);
+
+	memset(&smsg, 0x00, sizeof(struct msghdr));
+	smsg.msg_iov = &iov;
+	smsg.msg_iovlen = 1;
+	smsg.msg_control = cred_msg;
+	smsg.msg_controllen = sizeof(cred_msg);
+
+	retval = recvmsg(sock, &smsg, 0);
+	if (retval <  0) {
+		if (errno != EINTR)
+			dbg("unable to receive message");
+		return;
 	}
-	memcpy(new_msg, msg, sizeof(*new_msg));
+	cmsg = CMSG_FIRSTHDR(&smsg);
+	cred = (struct ucred *) CMSG_DATA(cmsg);
 
-	/* store timestamp of queuing */
-	new_msg->queue_time = time(NULL);
+	if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
+		dbg("no sender credentials received, message ignored");
+		goto skip;
+	}
 
-	/* 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 (cred->uid != 0) {
+		dbg("sender uid=%i, message ignored", cred->uid);
+		goto skip;
+	}
+
+	if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+		dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+		goto skip;
+	}
+
+	/* 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);
+	}
+	return;
 
-	return 0;
+skip:
+	free(msg);
+	return;
 }
 
-static void work(void)
+asmlinkage static void sig_handler(int signum)
 {
-	struct hotplug_msg *msg;
-	int msgid;
-	key_t key;
-	char buf[BUFFER_SIZE];
-	int ret;
-
-	key = ftok(UDEVD_EXEC, IPC_KEY_ID);
-	msg = (struct hotplug_msg *) buf;
-	msgid = msgget(key, IPC_CREAT);
-	if (msgid == -1) {
-		dbg("open message queue error");
-		exit(1);
+	int rc;
+
+	switch (signum) {
+		case SIGINT:
+		case SIGTERM:
+			exit(20 + signum);
+			break;
+		case SIGALRM:
+			/* set flag, then write to pipe if needed */
+			run_msg_q = 1;
+			goto do_write;
+			break;
+		case SIGCHLD:
+			/* set flag, then write to pipe if needed */
+			children_waiting = 1;
+			goto do_write;
+			break;
+		default:
+			dbg("unhandled signal %d", signum);
+			return;
 	}
-	while (1) {
-		ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0);
-		if (ret != -1) {
-			/* init the expected sequence with value from first call */
-			if (expect_seqnum == 0) {
-				expect_seqnum = msg->seqnum;
-				dbg("init next expected sequence number to %d", expect_seqnum);
-			}
-			dbg("current sequence %d, expected sequence %d", msg->seqnum, expect_seqnum);
-			if (msg->seqnum == expect_seqnum) {
-				/* execute expected event */
-				dispatch_msg(msg);
-				expect_seqnum++;
-				check_queue();
-				dump_queue();
-				continue;
-			}
-			if (msg->seqnum > expect_seqnum) {
-				/* something missing, queue event*/
-				queue_msg(msg);
-				check_queue();
-				dump_queue();
-				continue;
-			}
-			dbg("too late for event with sequence %d, even skipped ", msg->seqnum);
-		} else {
-			if (errno == EINTR) {
-				/* timeout */
-				if (list_empty(&msg_list)) {
-					info("we have nothing to do, so daemon exits...");
-					if (lock_file >= 0) {
-						close(lock_file);
-						unlink(lock_filename);
-					}
-					exit(0);
-				}
-				check_queue();
-				dump_queue();
-				continue;
-			}
-			dbg("ipc message receive error '%s'", strerror(errno));
-		}
+	
+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
+			sig_flag = 1;
 	}
 }
 
-static int one_and_only(void)
+static void udev_done(int pid)
 {
-	char string[100];
+	/* find msg associated with pid and delete it */
+	struct hotplug_msg *msg;
 
-	lock_file = open(lock_filename, O_RDWR | O_CREAT, 0x640);
+	list_for_each_entry(msg, &running_list, list) {
+		if (msg->pid == pid) {
+			dbg("<== exec seq %llu came back", msg->seqnum);
+			run_queue_delete(msg);
+
+			/* we want to run the exec queue manager since there may
+			 * be events waiting with the devpath of the one that
+			 * just finished
+			 */
+			run_exec_q = 1;
+			return;
+		}
+	}
+}
 
-	/* see if we can open */
-	if (lock_file < 0)
-		return -1;
-	
-	/* see if we can lock */
-	if (lockf(lock_file, F_TLOCK, 0) < 0) {
-		close(lock_file);
-		unlink(lock_filename);
-		return -1;
+static void reap_kids()
+{
+	/* reap all dead children */
+	while(1) {
+		int pid = waitpid(-1, 0, WNOHANG);
+		if ((pid == -1) || (pid == 0))
+			break;
+		udev_done(pid);
 	}
+}
 
-	snprintf(string, sizeof(string), "%d\n", getpid());
-	write(lock_file, string, strlen(string));
+/* just read everything from the pipe and clear the flag,
+ * the useful flags were set in the signal handler
+ */
+static void user_sighandler()
+{
+	int sig;
+	while(1) {
+		int rc = read(pipefds[0],&sig,sizeof(sig));
+		if (rc < 0)
+			break;
 
-	return 0;
+		sig_flag = 0;
+	}
 }
 
+
 int main(int argc, char *argv[])
 {
-	/* only let one version of the daemon run at any one time */
-	if (one_and_only() != 0)
-		exit(0);
+	int ssock, maxsockplus;
+	struct sockaddr_un saddr;
+	socklen_t addrlen;
+	int retval, fd;
+	const int on = 1;
+	struct sigaction act;
+	fd_set readfds;
+
+	init_logging("udevd");
+	dbg("version %s", UDEV_VERSION);
+
+	if (getuid() != 0) {
+		dbg("need to be root, exit");
+		exit(1);
+	}
+	/* make sure we are at top of dir */
+	chdir("/");
+	umask( umask( 077 ) | 022 );
+	/* Set fds to dev/null */
+	fd = open( "/dev/null", O_RDWR );
+	if ( fd < 0 ) {
+		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);
+	}
 
-	/* set up signal handler */
-	signal(SIGINT, sig_handler);
-	signal(SIGTERM, sig_handler);
-	signal(SIGKILL, sig_handler);
-	signal(SIGALRM, sig_handler);
+	retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
+	if (retval < 0) {
+		dbg("error fcntl on read pipe: %s", strerror(errno));
+		exit(1);
+	}
+	retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
+	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);
+	}
+	retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
+	if (retval < 0) {
+		dbg("error fcntl on write pipe: %s", strerror(errno));
+		exit(1);
+	}
 
-	/* we exit if we have nothing to do, next event will start us again */
-	set_timeout(UDEVD_TIMEOUT_SECONDS);
+	
+	/* set signal handlers */
+	act.sa_handler = sig_handler;
+	sigemptyset(&act.sa_mask);
+	act.sa_flags = SA_RESTART;
+	sigaction(SIGINT, &act, NULL);
+	sigaction(SIGTERM, &act, NULL);
+	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);
+
+	/* 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);
+	}
 
-	work();
-	exit(0);
+	/* 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");
+	if (udev_bin != NULL)
+		dbg("udev binary is set to '%s'", udev_bin);
+	else
+		udev_bin = UDEV_BIN;
+
+	FD_ZERO(&readfds);
+	FD_SET(ssock, &readfds);
+	FD_SET(pipefds[0], &readfds);
+	maxsockplus = ssock+1;
+	while (1) {
+		fd_set workreadfds = readfds;
+		retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
+
+		if (retval < 0) {
+			if (errno != EINTR)
+				dbg("error in select: %s", strerror(errno));
+			continue;
+		}
+
+		if (FD_ISSET(ssock, &workreadfds))
+			handle_msg(ssock);
+
+		if (FD_ISSET(pipefds[0], &workreadfds))
+			user_sighandler();
+
+		if (children_waiting) {
+			children_waiting = 0;
+			reap_kids();
+		}
+
+		if (run_msg_q) {
+			run_msg_q = 0;
+			msg_queue_manager();
+		}
+
+		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();
+			}
+
+			run_exec_q = 0;
+			exec_queue_manager();
+		}
+	}
+exit:
+	close(ssock);
+	exit(1);
 }