udevd.c revision 1aa1e24848903d11780db1ade355be73ad61a937
/*
* udevd.c - event listener and serializer
*
* Copyright (C) 2004-2005 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
* 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 <stddef.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 <syslog.h>
#include <time.h>
#include <sys/select.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/netlink.h>
#include "udev.h"
#include "udev_rules.h"
#include "udevd.h"
static struct udev_rules rules;
static int udevd_sock;
static int uevent_netlink_sock;
static int inotify_fd;
static pid_t sid;
static int signal_pipe[2] = {-1, -1};
static volatile int sigchilds_waiting;
static volatile int udev_exit;
static volatile int reload_config;
static int run_exec_q;
static int stop_exec_q;
static int max_childs;
static int max_childs_running;
static char udev_log[32];
static LIST_HEAD(exec_list);
static LIST_HEAD(running_list);
#ifdef USE_LOG
void log_message(int priority, const char *format, ...)
{
va_list args;
if (priority > udev_log_priority)
return;
va_start(args, format);
vsyslog(priority, format, args);
va_end(args);
}
#endif
static void asmlinkage udev_event_sig_handler(int signum)
{
if (signum == SIGALRM)
exit(1);
}
static int udev_event_process(struct uevent_msg *msg)
{
struct sigaction act;
struct udevice *udev;
int i;
int retval;
/* set signal handlers */
memset(&act, 0x00, sizeof(act));
act.sa_handler = (void (*)(int)) udev_event_sig_handler;
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
sigaction(SIGALRM, &act, NULL);
/* trigger timeout to prevent hanging processes */
alarm(UDEV_ALARM_TIMEOUT);
/* reconstruct event environment from message */
for (i = 0; msg->envp[i]; i++)
putenv(msg->envp[i]);
udev = udev_device_init();
if (udev == NULL)
return -1;
strlcpy(udev->action, msg->action, sizeof(udev->action));
sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
udev->devt = msg->devt;
retval = udev_device_event(&rules, udev);
/* run programs collected by RUN-key*/
if (retval == 0) {
struct name_entry *name_loop;
list_for_each_entry(name_loop, &udev->run_list, node) {
if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
else
if (run_program(name_loop->name, udev->dev->subsystem, NULL, 0, NULL,
(udev_log_priority >= LOG_INFO)))
retval = -1;
}
}
udev_device_cleanup(udev);
return retval;
}
enum event_state {
EVENT_QUEUED,
EVENT_FINISHED,
EVENT_FAILED,
};
static void export_event_state(struct uevent_msg *msg, enum event_state state)
{
char filename[PATH_SIZE];
char filename_failed[PATH_SIZE];
char target[PATH_SIZE];
size_t start, end, i;
struct uevent_msg *loop_msg;
/* add location of queue files */
strlcpy(filename, udev_root, sizeof(filename));
strlcat(filename, "/", sizeof(filename));
start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
end = strlcat(filename, msg->devpath, sizeof(filename));
if (end > sizeof(filename))
end = sizeof(filename);
/* replace '/' to transform path into a filename */
for (i = start+1; i < end; i++)
if (filename[i] == '/')
filename[i] = PATH_TO_NAME_CHAR;
/* add location of failed files */
strlcpy(filename_failed, udev_root, sizeof(filename_failed));
strlcat(filename_failed, "/", sizeof(filename_failed));
start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
if (end > sizeof(filename_failed))
end = sizeof(filename_failed);
/* replace '/' to transform path into a filename */
for (i = start+1; i < end; i++)
if (filename_failed[i] == '/')
filename_failed[i] = PATH_TO_NAME_CHAR;
switch (state) {
case EVENT_QUEUED:
unlink(filename_failed);
delete_path(filename_failed);
strlcpy(target, sysfs_path, sizeof(target));
strlcat(target, msg->devpath, sizeof(target));
create_path(filename);
symlink(target, filename);
return;
case EVENT_FINISHED:
case EVENT_FAILED:
unlink(filename_failed);
delete_path(filename_failed);
/* don't remove, if events for the same path are still pending */
list_for_each_entry(loop_msg, &running_list, node)
if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
return;
/* move failed events to the failed directory */
if (state == EVENT_FAILED) {
create_path(filename_failed);
rename(filename, filename_failed);
} else {
unlink(filename);
}
/* clean up the queue directory */
delete_path(filename);
return;
}
}
static void msg_queue_delete(struct uevent_msg *msg)
{
list_del(&msg->node);
/* mark as failed, if add event returns non-zero */
if (msg->exitstatus && strcmp(msg->action, "add") == 0)
export_event_state(msg, EVENT_FAILED);
else
export_event_state(msg, EVENT_FINISHED);
free(msg);
}
static void udev_event_run(struct uevent_msg *msg)
{
pid_t pid;
int retval;
pid = fork();
switch (pid) {
case 0:
/* child */
close(uevent_netlink_sock);
close(udevd_sock);
if (inotify_fd > 0)
close(inotify_fd);
close(signal_pipe[READ_END]);
close(signal_pipe[WRITE_END]);
logging_close();
logging_init("udevd-event");
setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
retval = udev_event_process(msg);
info("seq %llu finished", msg->seqnum);
logging_close();
if (retval)
exit(1);
exit(0);
case -1:
err("fork of child failed: %s", strerror(errno));
msg_queue_delete(msg);
break;
default:
/* get SIGCHLD in main loop */
info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
msg->seqnum, pid, msg->action, msg->subsystem, time(NULL) - msg->queue_time);
msg->pid = pid;
}
}
static void msg_queue_insert(struct uevent_msg *msg)
{
msg->queue_time = time(NULL);
export_event_state(msg, EVENT_QUEUED);
/* run all events with a timeout set immediately */
if (msg->timeout != 0) {
list_add_tail(&msg->node, &running_list);
udev_event_run(msg);
return;
}
list_add_tail(&msg->node, &exec_list);
run_exec_q = 1;
}
/* runs event and removes event from run queue when finished */
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)-1);
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)-1);
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 int running_with_devpath(struct uevent_msg *msg, int limit)
{
struct uevent_msg *loop_msg;
int childs_count = 0;
list_for_each_entry(loop_msg, &running_list, node) {
if (limit && childs_count++ > limit) {
dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
return 1;
}
/* return running parent/child device event */
if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
dbg("%llu, child device event still running %llu (%s)",
msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
return 2;
}
/* return running physical device event */
if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
dbg("%llu, physical device event still running %llu (%s)",
msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
return 3;
}
}
return 0;
}
/* exec queue management routine executes the events and serializes events in the same sequence */
static void msg_queue_manager(void)
{
struct uevent_msg *loop_msg;
struct uevent_msg *tmp_msg;
int running;
if (list_empty(&exec_list))
return;
running = running_processes();
dbg("%d processes runnning on system", running);
if (running < 0)
running = max_childs_running;
list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
/* check running processes in our session and possibly throttle */
if (running >= max_childs_running) {
running = running_processes_in_session(sid, max_childs_running+10);
dbg("at least %d processes running in session", running);
if (running >= max_childs_running) {
dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
return;
}
}
/* don't run two processes for the same devpath and wait for the parent*/
if (running_with_devpath(loop_msg, max_childs)) {
dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
continue;
}
/* move event to run list */
list_move_tail(&loop_msg->node, &running_list);
udev_event_run(loop_msg);
running++;
dbg("moved seq %llu to running list", loop_msg->seqnum);
}
}
static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
{
int bufpos;
int i;
struct uevent_msg *msg;
int major = 0;
int minor = 0;
msg = malloc(sizeof(struct uevent_msg) + buf_size);
if (msg == NULL)
return NULL;
memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
/* copy environment buffer and reconstruct envp */
memcpy(msg->envbuf, buf, buf_size);
bufpos = 0;
for (i = 0; (bufpos < buf_size) && (i < UEVENT_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];
else if (strncmp(key, "DEVPATH=", 8) == 0)
msg->devpath = &key[8];
else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
msg->subsystem = &key[10];
else if (strncmp(key, "SEQNUM=", 7) == 0)
msg->seqnum = strtoull(&key[7], NULL, 10);
else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
msg->physdevpath = &key[12];
else if (strncmp(key, "MAJOR=", 6) == 0)
major = strtoull(&key[6], NULL, 10);
else if (strncmp(key, "MINOR=", 6) == 0)
minor = strtoull(&key[6], NULL, 10);
else if (strncmp(key, "TIMEOUT=", 8) == 0)
msg->timeout = strtoull(&key[8], NULL, 10);
}
msg->devt = makedev(major, minor);
msg->envp[i++] = "UDEVD_EVENT=1";
msg->envp[i] = NULL;
if (!msg->devpath) {
info("DEVPATH missing, ignore message");
free(msg);
return NULL;
}
return msg;
}
/* receive the udevd message from userspace */
static struct uevent_msg *get_udevd_msg(void)
{
static struct udevd_msg usend_msg;
struct uevent_msg *msg;
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;
int *intval;
memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
iov.iov_base = &usend_msg;
iov.iov_len = sizeof(struct udevd_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);
size = recvmsg(udevd_sock, &smsg, 0);
if (size < 0) {
if (errno != EINTR)
err("unable to receive user udevd message: %s", strerror(errno));
return NULL;
}
cmsg = CMSG_FIRSTHDR(&smsg);
cred = (struct ucred *) CMSG_DATA(cmsg);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
err("no sender credentials received, message ignored");
return NULL;
}
if (cred->uid != 0) {
err("sender uid=%i, message ignored", cred->uid);
return NULL;
}
if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
return NULL;
}
switch (usend_msg.type) {
case UDEVD_UEVENT_UDEVSEND:
case UDEVD_UEVENT_INITSEND:
info("udevd event message received");
envbuf_size = size - offsetof(struct udevd_msg, envbuf);
dbg("envbuf_size=%i", envbuf_size);
msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
if (msg == NULL)
return NULL;
msg->type = usend_msg.type;
return msg;
case UDEVD_STOP_EXEC_QUEUE:
info("udevd message (STOP_EXEC_QUEUE) received");
stop_exec_q = 1;
break;
case UDEVD_START_EXEC_QUEUE:
info("udevd message (START_EXEC_QUEUE) received");
stop_exec_q = 0;
msg_queue_manager();
break;
case UDEVD_SET_LOG_LEVEL:
intval = (int *) usend_msg.envbuf;
info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
udev_log_priority = *intval;
sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
putenv(udev_log);
break;
case UDEVD_SET_MAX_CHILDS:
intval = (int *) usend_msg.envbuf;
info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
max_childs = *intval;
break;
case UDEVD_RELOAD_RULES:
info("udevd message (RELOAD_RULES) received");
reload_config = 1;
break;
default:
dbg("unknown message type");
}
return NULL;
}
/* receive the kernel user event message and do some sanity checks */
static struct uevent_msg *get_netlink_msg(void)
{
struct uevent_msg *msg;
int bufpos;
ssize_t size;
static char buffer[UEVENT_BUFFER_SIZE + 512];
char *pos;
size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
if (size < 0) {
if (errno != EINTR)
err("unable to receive kernel netlink message: %s", strerror(errno));
return NULL;
}
if ((size_t)size > sizeof(buffer)-1)
size = sizeof(buffer)-1;
buffer[size] = '\0';
dbg("uevent_size=%zi", size);
/* start of event payload */
bufpos = strlen(buffer)+1;
msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
if (msg == NULL)
return NULL;
msg->type = UDEVD_UEVENT_NETLINK;
/* validate message */
pos = strchr(buffer, '@');
if (pos == NULL) {
err("invalid uevent '%s'", buffer);
free(msg);
return NULL;
}
pos[0] = '\0';
if (msg->action == NULL) {
info("no ACTION in payload found, skip event '%s'", buffer);
free(msg);
return NULL;
}
if (strcmp(msg->action, buffer) != 0) {
err("ACTION in payload does not match uevent, skip event '%s'", buffer);
free(msg);
return NULL;
}
return msg;
}
static void asmlinkage sig_handler(int signum)
{
switch (signum) {
case SIGINT:
case SIGTERM:
udev_exit = 1;
break;
case SIGCHLD:
/* set flag, then write to pipe if needed */
sigchilds_waiting = 1;
break;
case SIGHUP:
reload_config = 1;
break;
}
/* write to pipe, which will wakeup select() in our mainloop */
write(signal_pipe[WRITE_END], "", 1);
}
static void udev_done(int pid, int exitstatus)
{
/* find msg associated with pid and delete it */
struct uevent_msg *msg;
list_for_each_entry(msg, &running_list, node) {
if (msg->pid == pid) {
info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
exitstatus, time(NULL) - msg->queue_time);
msg->exitstatus = exitstatus;
msg_queue_delete(msg);
/* there may be events waiting with the same devpath */
run_exec_q = 1;
return;
}
}
}
static void reap_sigchilds(void)
{
pid_t pid;
int status;
while (1) {
pid = waitpid(-1, &status, WNOHANG);
if (pid <= 0)
break;
if (WIFEXITED(status))
status = WEXITSTATUS(status);
else if (WIFSIGNALED(status))
status = WTERMSIG(status) + 128;
else
status = 0;
udev_done(pid, status);
}
}
static int init_udevd_socket(void)
{
struct sockaddr_un saddr;
const int buffersize = 16 * 1024 * 1024;
socklen_t addrlen;
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;
udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
if (udevd_sock == -1) {
err("error getting socket: %s", strerror(errno));
return -1;
}
/* set receive buffersize */
setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
/* the bind takes care of ensuring only one copy running */
retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
if (retval < 0) {
err("bind failed: %s", strerror(errno));
return -1;
}
/* enable receiving of the sender credentials */
setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
return 0;
}
static int init_uevent_netlink_sock(void)
{
struct sockaddr_nl snl;
const int buffersize = 16 * 1024 * 1024;
int retval;
memset(&snl, 0x00, sizeof(struct sockaddr_nl));
snl.nl_family = AF_NETLINK;
snl.nl_pid = getpid();
snl.nl_groups = 0xffffffff;
uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
if (uevent_netlink_sock == -1) {
err("error getting socket: %s", strerror(errno));
return -1;
}
/* set receive buffersize */
setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
if (retval < 0) {
err("bind failed: %s", strerror(errno));
close(uevent_netlink_sock);
uevent_netlink_sock = -1;
return -1;
}
return 0;
}
int main(int argc, char *argv[], char *envp[])
{
int retval;
int fd;
struct sigaction act;
fd_set readfds;
const char *value;
int daemonize = 0;
int i;
int rc = 0;
int maxfd;
/* redirect std fd's, if the kernel forks us, we don't have them at all */
fd = open("/dev/null", O_RDWR);
if (fd >= 0) {
if (fd != STDIN_FILENO)
dup2(fd, STDIN_FILENO);
if (fd != STDOUT_FILENO)
dup2(fd, STDOUT_FILENO);
if (fd != STDERR_FILENO)
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO)
close(fd);
}
logging_init("udevd");
if (fd < 0)
err("fatal, could not open /dev/null: %s", strerror(errno));
udev_config_init();
dbg("version %s", UDEV_VERSION);
if (getuid() != 0) {
err("need to be root, exit");
goto exit;
}
/* parse commandline options */
for (i = 1 ; i < argc; i++) {
char *arg = argv[i];
if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
info("will daemonize");
daemonize = 1;
}
if (strcmp(arg, "--stop-exec-queue") == 0) {
info("will not execute events until START_EXEC_QUEUE is received");
stop_exec_q = 1;
}
}
/* init sockets to receive events */
if (init_udevd_socket() < 0) {
if (errno == EADDRINUSE) {
err("another udevd running, exit");
rc = 1;
} else {
err("error initializing udevd socket: %s", strerror(errno));
rc = 2;
}
goto exit;
}
if (init_uevent_netlink_sock() < 0) {
err("uevent socket not available");
rc = 3;
goto exit;
}
/* parse the rules and keep it in memory */
sysfs_init();
udev_rules_init(&rules, 1);
if (daemonize) {
pid_t pid;
pid = fork();
switch (pid) {
case 0:
dbg("daemonized fork running");
break;
case -1:
err("fork of daemon failed: %s", strerror(errno));
rc = 4;
goto exit;
default:
dbg("child [%u] running, parent exits", pid);
goto exit;
}
}
/* set scheduling priority for the daemon */
setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
chdir("/");
umask(022);
/* become session leader */
sid = setsid();
dbg("our session is %d", sid);
/* OOM_DISABLE == -17 */
fd = open("/proc/self/oom_adj", O_RDWR);
if (fd < 0)
err("error disabling OOM: %s", strerror(errno));
else {
write(fd, "-17", 3);
close(fd);
}
/* setup signal handler pipe */
retval = pipe(signal_pipe);
if (retval < 0) {
err("error getting pipes: %s", strerror(errno));
goto exit;
}
retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
if (retval < 0) {
err("error fcntl on read pipe: %s", strerror(errno));
goto exit;
}
retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
if (retval < 0) {
err("error fcntl on write pipe: %s", strerror(errno));
goto exit;
}
/* 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;
sigaction(SIGINT, &act, NULL);
sigaction(SIGTERM, &act, NULL);
sigaction(SIGCHLD, &act, NULL);
sigaction(SIGHUP, &act, NULL);
/* watch rules directory */
inotify_fd = inotify_init();
if (inotify_fd > 0)
inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
/* maximum limit of forked childs */
value = getenv("UDEVD_MAX_CHILDS");
if (value)
max_childs = strtoul(value, NULL, 10);
else
max_childs = UDEVD_MAX_CHILDS;
info("initialize max_childs to %u", max_childs);
/* start to throttle forking if maximum number of _running_ childs is reached */
value = getenv("UDEVD_MAX_CHILDS_RUNNING");
if (value)
max_childs_running = strtoull(value, NULL, 10);
else
max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
info("initialize max_childs_running to %u", max_childs_running);
/* clear environment for forked event processes */
clearenv();
/* export log_priority , as called programs may want to follow that setting */
sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
putenv(udev_log);
maxfd = udevd_sock;
maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
maxfd = UDEV_MAX(maxfd, inotify_fd);
while (!udev_exit) {
struct uevent_msg *msg;
int fdcount;
FD_ZERO(&readfds);
FD_SET(signal_pipe[READ_END], &readfds);
FD_SET(udevd_sock, &readfds);
FD_SET(uevent_netlink_sock, &readfds);
if (inotify_fd > 0)
FD_SET(inotify_fd, &readfds);
fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
if (fdcount < 0) {
if (errno != EINTR)
err("error in select: %s", strerror(errno));
continue;
}
/* get user socket message */
if (FD_ISSET(udevd_sock, &readfds)) {
msg = get_udevd_msg();
if (msg)
msg_queue_insert(msg);
}
/* get kernel netlink message */
if (FD_ISSET(uevent_netlink_sock, &readfds)) {
msg = get_netlink_msg();
if (msg)
msg_queue_insert(msg);
}
/* received a signal, clear our notification pipe */
if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
char buf[256];
read(signal_pipe[READ_END], &buf, sizeof(buf));
}
/* rules directory inotify watch */
if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
int nbytes;
/* discard all possible events, we can just reload the config */
if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
char *buf;
reload_config = 1;
buf = malloc(nbytes);
if (!buf) {
err("error getting buffer for inotify, disable watching");
close(inotify_fd);
inotify_fd = -1;
}
read(inotify_fd, buf, nbytes);
free(buf);
}
}
/* rules changed, set by inotify or a signal*/
if (reload_config) {
reload_config = 0;
udev_rules_cleanup(&rules);
udev_rules_init(&rules, 1);
}
/* forked child has returned */
if (sigchilds_waiting) {
sigchilds_waiting = 0;
reap_sigchilds();
}
if (run_exec_q) {
run_exec_q = 0;
if (!stop_exec_q)
msg_queue_manager();
}
}
exit:
udev_rules_cleanup(&rules);
sysfs_cleanup();
if (signal_pipe[READ_END] > 0)
close(signal_pipe[READ_END]);
if (signal_pipe[WRITE_END] > 0)
close(signal_pipe[WRITE_END]);
if (udevd_sock > 0)
close(udevd_sock);
if (inotify_fd > 0)
close(inotify_fd);
if (uevent_netlink_sock > 0)
close(uevent_netlink_sock);
logging_close();
return rc;
}