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mirror of https://github.com/systemd/systemd-stable.git synced 2024-10-30 06:25:25 +03:00
systemd-stable/udevd.c

420 lines
10 KiB
C

/*
* udevd.c - hotplug event serializer
*
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <pthread.h>
#include <stddef.h>
#include <sys/types.h>
#include <sys/wait.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"
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 void msg_dump_queue(void)
{
struct hotplug_msg *msg;
list_for_each_entry(msg, &msg_list, list)
dbg("sequence %d in queue", msg->seqnum);
}
static void msg_dump(struct hotplug_msg *msg)
{
dbg("sequence %d, '%s', '%s', '%s'",
msg->seqnum, msg->action, msg->devpath, msg->subsystem);
}
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 NULL;
}
return new_msg;
}
static void msg_delete(struct hotplug_msg *msg)
{
if (msg != NULL)
free(msg);
}
/* orders the message in the queue by sequence number */
static void msg_queue_insert(struct hotplug_msg *msg)
{
struct hotplug_msg *loop_msg;
/* 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);
/* 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;
msg = parm;
setenv("ACTION", msg->action, 1);
setenv("DEVPATH", msg->devpath, 1);
pid = fork();
switch (pid) {
case 0:
/* child */
execl(UDEV_BIN, "udev", msg->subsystem, NULL);
dbg("exec of child failed");
exit(1);
break;
case -1:
dbg("fork of child failed");
goto exit;
default:
/* 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);
}
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);
}
/* returns already running task with devpath */
static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
{
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;
}
/* 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 = 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);
}
}
/* every connect creates a thread which gets the msg, queues it and exits */
static void *client_threads(void * parm)
{
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;
}
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;
}
pthread_mutex_lock(&msg_lock);
msg_queue_insert(msg);
pthread_mutex_unlock(&msg_lock);
exit:
close(sock);
pthread_exit(0);
}
static void sig_handler(int signum)
{
switch (signum) {
case SIGINT:
case SIGTERM:
unlink(UDEVD_LOCK);
unlink(UDEVD_SOCK);
exit(20 + signum);
break;
default:
dbg("unhandled signal");
}
}
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;
}
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;
init_logging("udevd");
/* only let one version of the daemon run at any one time */
if (one_and_only() != 0)
exit(0);
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
memset(&saddr, 0x00, sizeof(saddr));
saddr.sun_family = AF_LOCAL;
strcpy(saddr.sun_path, UDEVD_SOCK);
unlink(UDEVD_SOCK);
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 */
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);
unlink(UDEVD_SOCK);
exit(1);
}