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Systemd/src/udev/udevd.c

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/*
* Copyright (C) 2004-2012 Kay Sievers <kay@vrfy.org>
* Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
* Copyright (C) 2009 Canonical Ltd.
* Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
*
* 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, either version 2 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <stddef.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <time.h>
#include <getopt.h>
#include <dirent.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/signalfd.h>
#include <sys/epoll.h>
#include <sys/mount.h>
#include <sys/poll.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/inotify.h>
#include <sys/utsname.h>
#include "udev.h"
#include "udev-util.h"
#include "rtnl-util.h"
#include "sd-daemon.h"
#include "cgroup-util.h"
#include "dev-setup.h"
#include "fileio.h"
void udev_main_log(struct udev *udev, int priority,
const char *file, int line, const char *fn,
const char *format, va_list args) {
log_metav(priority, file, line, fn, format, args);
}
static struct udev_rules *rules;
static struct udev_ctrl *udev_ctrl;
static struct udev_monitor *monitor;
static int worker_watch[2] = { -1, -1 };
static int fd_signal = -1;
static int fd_ep = -1;
static int fd_inotify = -1;
static bool stop_exec_queue;
static bool reload;
static int children;
static bool arg_debug = false;
static int arg_daemonize = false;
static int arg_resolve_names = 1;
static int arg_children_max;
static int arg_exec_delay;
static usec_t arg_event_timeout_usec = 180 * USEC_PER_SEC;
static usec_t arg_event_timeout_warn_usec = 180 * USEC_PER_SEC / 3;
static sigset_t sigmask_orig;
static UDEV_LIST(event_list);
static UDEV_LIST(worker_list);
static char *udev_cgroup;
static bool udev_exit;
enum event_state {
EVENT_UNDEF,
EVENT_QUEUED,
EVENT_RUNNING,
};
struct event {
struct udev_list_node node;
struct udev *udev;
struct udev_device *dev;
enum event_state state;
int exitcode;
unsigned long long int delaying_seqnum;
unsigned long long int seqnum;
const char *devpath;
size_t devpath_len;
const char *devpath_old;
dev_t devnum;
int ifindex;
bool is_block;
};
static inline struct event *node_to_event(struct udev_list_node *node) {
return container_of(node, struct event, node);
}
static void event_queue_cleanup(struct udev *udev, enum event_state type);
enum worker_state {
WORKER_UNDEF,
WORKER_RUNNING,
WORKER_IDLE,
WORKER_KILLED,
};
struct worker {
struct udev_list_node node;
struct udev *udev;
int refcount;
pid_t pid;
struct udev_monitor *monitor;
enum worker_state state;
struct event *event;
usec_t event_start_usec;
bool event_warned;
};
/* passed from worker to main process */
struct worker_message {
pid_t pid;
int exitcode;
};
static inline struct worker *node_to_worker(struct udev_list_node *node) {
return container_of(node, struct worker, node);
}
static void event_queue_delete(struct event *event) {
udev_list_node_remove(&event->node);
udev_device_unref(event->dev);
free(event);
}
static struct worker *worker_ref(struct worker *worker) {
worker->refcount++;
return worker;
}
static void worker_cleanup(struct worker *worker) {
udev_list_node_remove(&worker->node);
udev_monitor_unref(worker->monitor);
children--;
free(worker);
}
static void worker_unref(struct worker *worker) {
worker->refcount--;
if (worker->refcount > 0)
return;
log_debug("worker [%u] cleaned up", worker->pid);
worker_cleanup(worker);
}
static void worker_list_cleanup(struct udev *udev) {
struct udev_list_node *loop, *tmp;
udev_list_node_foreach_safe(loop, tmp, &worker_list) {
struct worker *worker = node_to_worker(loop);
worker_cleanup(worker);
}
}
static void worker_new(struct event *event) {
struct udev *udev = event->udev;
struct worker *worker;
struct udev_monitor *worker_monitor;
pid_t pid;
/* listen for new events */
worker_monitor = udev_monitor_new_from_netlink(udev, NULL);
if (worker_monitor == NULL)
return;
/* allow the main daemon netlink address to send devices to the worker */
udev_monitor_allow_unicast_sender(worker_monitor, monitor);
udev_monitor_enable_receiving(worker_monitor);
worker = new0(struct worker, 1);
if (worker == NULL) {
udev_monitor_unref(worker_monitor);
return;
}
/* worker + event reference */
worker->refcount = 2;
worker->udev = udev;
pid = fork();
switch (pid) {
case 0: {
struct udev_device *dev = NULL;
int fd_monitor;
_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
struct epoll_event ep_signal, ep_monitor;
sigset_t mask;
int rc = EXIT_SUCCESS;
/* take initial device from queue */
dev = event->dev;
event->dev = NULL;
free(worker);
worker_list_cleanup(udev);
event_queue_cleanup(udev, EVENT_UNDEF);
udev_monitor_unref(monitor);
udev_ctrl_unref(udev_ctrl);
close(fd_signal);
close(fd_ep);
close(worker_watch[READ_END]);
sigfillset(&mask);
fd_signal = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
if (fd_signal < 0) {
log_error("error creating signalfd %m");
rc = 2;
goto out;
}
fd_ep = epoll_create1(EPOLL_CLOEXEC);
if (fd_ep < 0) {
log_error("error creating epoll fd: %m");
rc = 3;
goto out;
}
memzero(&ep_signal, sizeof(struct epoll_event));
ep_signal.events = EPOLLIN;
ep_signal.data.fd = fd_signal;
fd_monitor = udev_monitor_get_fd(worker_monitor);
memzero(&ep_monitor, sizeof(struct epoll_event));
ep_monitor.events = EPOLLIN;
ep_monitor.data.fd = fd_monitor;
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_signal, &ep_signal) < 0 ||
epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_monitor, &ep_monitor) < 0) {
log_error("fail to add fds to epoll: %m");
rc = 4;
goto out;
}
/* request TERM signal if parent exits */
prctl(PR_SET_PDEATHSIG, SIGTERM);
/* reset OOM score, we only protect the main daemon */
write_string_file("/proc/self/oom_score_adj", "0");
for (;;) {
struct udev_event *udev_event;
struct worker_message msg;
int fd_lock = -1;
int err = 0;
log_debug("seq %llu running", udev_device_get_seqnum(dev));
udev_event = udev_event_new(dev);
if (udev_event == NULL) {
rc = 5;
goto out;
}
/* needed for SIGCHLD/SIGTERM in spawn() */
udev_event->fd_signal = fd_signal;
if (arg_exec_delay > 0)
udev_event->exec_delay = arg_exec_delay;
/*
* Take a shared lock on the device node; this establishes
* a concept of device "ownership" to serialize device
* access. External processes holding an exclusive lock will
* cause udev to skip the event handling; in the case udev
* acquired the lock, the external process can block until
* udev has finished its event handling.
*/
if (!streq_ptr(udev_device_get_action(dev), "remove") &&
streq_ptr("block", udev_device_get_subsystem(dev)) &&
!startswith(udev_device_get_sysname(dev), "dm-") &&
!startswith(udev_device_get_sysname(dev), "md")) {
struct udev_device *d = dev;
if (streq_ptr("partition", udev_device_get_devtype(d)))
d = udev_device_get_parent(d);
if (d) {
fd_lock = open(udev_device_get_devnode(d), O_RDONLY|O_CLOEXEC|O_NOFOLLOW|O_NONBLOCK);
if (fd_lock >= 0 && flock(fd_lock, LOCK_SH|LOCK_NB) < 0) {
log_debug("Unable to flock(%s), skipping event handling: %m", udev_device_get_devnode(d));
err = -EWOULDBLOCK;
fd_lock = safe_close(fd_lock);
goto skip;
}
}
}
/* needed for renaming netifs */
udev_event->rtnl = rtnl;
/* apply rules, create node, symlinks */
udev_event_execute_rules(udev_event, arg_event_timeout_usec, arg_event_timeout_warn_usec, rules, &sigmask_orig);
udev_event_execute_run(udev_event, arg_event_timeout_usec, arg_event_timeout_warn_usec, &sigmask_orig);
/* in case rtnl was initialized */
rtnl = sd_rtnl_ref(udev_event->rtnl);
/* apply/restore inotify watch */
if (udev_event->inotify_watch) {
udev_watch_begin(udev, dev);
udev_device_update_db(dev);
}
safe_close(fd_lock);
/* send processed event back to libudev listeners */
udev_monitor_send_device(worker_monitor, NULL, dev);
skip:
/* send udevd the result of the event execution */
memzero(&msg, sizeof(struct worker_message));
msg.exitcode = err;
msg.pid = getpid();
send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
log_debug("seq %llu processed with %i", udev_device_get_seqnum(dev), err);
udev_device_unref(dev);
dev = NULL;
if (udev_event->sigterm) {
udev_event_unref(udev_event);
goto out;
}
udev_event_unref(udev_event);
/* wait for more device messages from main udevd, or term signal */
while (dev == NULL) {
struct epoll_event ev[4];
int fdcount;
int i;
fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), -1);
if (fdcount < 0) {
if (errno == EINTR)
continue;
log_error("failed to poll: %m");
goto out;
}
for (i = 0; i < fdcount; i++) {
if (ev[i].data.fd == fd_monitor && ev[i].events & EPOLLIN) {
dev = udev_monitor_receive_device(worker_monitor);
break;
} else if (ev[i].data.fd == fd_signal && ev[i].events & EPOLLIN) {
struct signalfd_siginfo fdsi;
ssize_t size;
size = read(fd_signal, &fdsi, sizeof(struct signalfd_siginfo));
if (size != sizeof(struct signalfd_siginfo))
continue;
switch (fdsi.ssi_signo) {
case SIGTERM:
goto out;
}
}
}
}
}
out:
udev_device_unref(dev);
safe_close(fd_signal);
safe_close(fd_ep);
close(fd_inotify);
close(worker_watch[WRITE_END]);
udev_rules_unref(rules);
udev_builtin_exit(udev);
udev_monitor_unref(worker_monitor);
udev_unref(udev);
log_close();
exit(rc);
}
case -1:
udev_monitor_unref(worker_monitor);
event->state = EVENT_QUEUED;
free(worker);
log_error("fork of child failed: %m");
break;
default:
/* close monitor, but keep address around */
udev_monitor_disconnect(worker_monitor);
worker->monitor = worker_monitor;
worker->pid = pid;
worker->state = WORKER_RUNNING;
worker->event_start_usec = now(CLOCK_MONOTONIC);
worker->event_warned = false;
worker->event = event;
event->state = EVENT_RUNNING;
udev_list_node_append(&worker->node, &worker_list);
children++;
log_debug("seq %llu forked new worker [%u]", udev_device_get_seqnum(event->dev), pid);
break;
}
}
static void event_run(struct event *event) {
struct udev_list_node *loop;
udev_list_node_foreach(loop, &worker_list) {
struct worker *worker = node_to_worker(loop);
ssize_t count;
if (worker->state != WORKER_IDLE)
continue;
count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
if (count < 0) {
log_error("worker [%u] did not accept message %zi (%m), kill it", worker->pid, count);
kill(worker->pid, SIGKILL);
worker->state = WORKER_KILLED;
continue;
}
worker_ref(worker);
worker->event = event;
worker->state = WORKER_RUNNING;
worker->event_start_usec = now(CLOCK_MONOTONIC);
worker->event_warned = false;
event->state = EVENT_RUNNING;
return;
}
if (children >= arg_children_max) {
if (arg_children_max > 1)
log_debug("maximum number (%i) of children reached", children);
return;
}
/* start new worker and pass initial device */
worker_new(event);
}
static int event_queue_insert(struct udev_device *dev) {
struct event *event;
event = new0(struct event, 1);
if (event == NULL)
return -1;
event->udev = udev_device_get_udev(dev);
event->dev = dev;
event->seqnum = udev_device_get_seqnum(dev);
event->devpath = udev_device_get_devpath(dev);
event->devpath_len = strlen(event->devpath);
event->devpath_old = udev_device_get_devpath_old(dev);
event->devnum = udev_device_get_devnum(dev);
event->is_block = streq("block", udev_device_get_subsystem(dev));
event->ifindex = udev_device_get_ifindex(dev);
log_debug("seq %llu queued, '%s' '%s'", udev_device_get_seqnum(dev),
udev_device_get_action(dev), udev_device_get_subsystem(dev));
event->state = EVENT_QUEUED;
udev_list_node_append(&event->node, &event_list);
return 0;
}
static void worker_kill(struct udev *udev) {
struct udev_list_node *loop;
udev_list_node_foreach(loop, &worker_list) {
struct worker *worker = node_to_worker(loop);
if (worker->state == WORKER_KILLED)
continue;
worker->state = WORKER_KILLED;
kill(worker->pid, SIGTERM);
}
}
/* lookup event for identical, parent, child device */
static bool is_devpath_busy(struct event *event) {
struct udev_list_node *loop;
size_t common;
/* check if queue contains events we depend on */
udev_list_node_foreach(loop, &event_list) {
struct event *loop_event = node_to_event(loop);
/* we already found a later event, earlier can not block us, no need to check again */
if (loop_event->seqnum < event->delaying_seqnum)
continue;
/* event we checked earlier still exists, no need to check again */
if (loop_event->seqnum == event->delaying_seqnum)
return true;
/* found ourself, no later event can block us */
if (loop_event->seqnum >= event->seqnum)
break;
/* check major/minor */
if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
return true;
/* check network device ifindex */
if (event->ifindex != 0 && event->ifindex == loop_event->ifindex)
return true;
/* check our old name */
if (event->devpath_old != NULL && streq(loop_event->devpath, event->devpath_old)) {
event->delaying_seqnum = loop_event->seqnum;
return true;
}
/* compare devpath */
common = MIN(loop_event->devpath_len, event->devpath_len);
/* one devpath is contained in the other? */
if (memcmp(loop_event->devpath, event->devpath, common) != 0)
continue;
/* identical device event found */
if (loop_event->devpath_len == event->devpath_len) {
/* devices names might have changed/swapped in the meantime */
if (major(event->devnum) != 0 && (event->devnum != loop_event->devnum || event->is_block != loop_event->is_block))
continue;
if (event->ifindex != 0 && event->ifindex != loop_event->ifindex)
continue;
event->delaying_seqnum = loop_event->seqnum;
return true;
}
/* parent device event found */
if (event->devpath[common] == '/') {
event->delaying_seqnum = loop_event->seqnum;
return true;
}
/* child device event found */
if (loop_event->devpath[common] == '/') {
event->delaying_seqnum = loop_event->seqnum;
return true;
}
/* no matching device */
continue;
}
return false;
}
static void event_queue_start(struct udev *udev) {
struct udev_list_node *loop;
udev_list_node_foreach(loop, &event_list) {
struct event *event = node_to_event(loop);
if (event->state != EVENT_QUEUED)
continue;
/* do not start event if parent or child event is still running */
if (is_devpath_busy(event))
continue;
event_run(event);
}
}
static void event_queue_cleanup(struct udev *udev, enum event_state match_type) {
struct udev_list_node *loop, *tmp;
udev_list_node_foreach_safe(loop, tmp, &event_list) {
struct event *event = node_to_event(loop);
if (match_type != EVENT_UNDEF && match_type != event->state)
continue;
event_queue_delete(event);
}
}
static void worker_returned(int fd_worker) {
for (;;) {
struct worker_message msg;
ssize_t size;
struct udev_list_node *loop;
size = recv(fd_worker, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
if (size != sizeof(struct worker_message))
break;
/* lookup worker who sent the signal */
udev_list_node_foreach(loop, &worker_list) {
struct worker *worker = node_to_worker(loop);
if (worker->pid != msg.pid)
continue;
/* worker returned */
if (worker->event) {
worker->event->exitcode = msg.exitcode;
event_queue_delete(worker->event);
worker->event = NULL;
}
if (worker->state != WORKER_KILLED)
worker->state = WORKER_IDLE;
worker_unref(worker);
break;
}
}
}
/* receive the udevd message from userspace */
static struct udev_ctrl_connection *handle_ctrl_msg(struct udev_ctrl *uctrl) {
struct udev *udev = udev_ctrl_get_udev(uctrl);
struct udev_ctrl_connection *ctrl_conn;
struct udev_ctrl_msg *ctrl_msg = NULL;
const char *str;
int i;
ctrl_conn = udev_ctrl_get_connection(uctrl);
if (ctrl_conn == NULL)
goto out;
ctrl_msg = udev_ctrl_receive_msg(ctrl_conn);
if (ctrl_msg == NULL)
goto out;
i = udev_ctrl_get_set_log_level(ctrl_msg);
if (i >= 0) {
log_debug("udevd message (SET_LOG_LEVEL) received, log_priority=%i", i);
log_set_max_level(i);
worker_kill(udev);
}
if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
log_debug("udevd message (STOP_EXEC_QUEUE) received");
stop_exec_queue = true;
}
if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
log_debug("udevd message (START_EXEC_QUEUE) received");
stop_exec_queue = false;
}
if (udev_ctrl_get_reload(ctrl_msg) > 0) {
log_debug("udevd message (RELOAD) received");
reload = true;
}
str = udev_ctrl_get_set_env(ctrl_msg);
if (str != NULL) {
char *key;
key = strdup(str);
if (key != NULL) {
char *val;
val = strchr(key, '=');
if (val != NULL) {
val[0] = '\0';
val = &val[1];
if (val[0] == '\0') {
log_debug("udevd message (ENV) received, unset '%s'", key);
udev_add_property(udev, key, NULL);
} else {
log_debug("udevd message (ENV) received, set '%s=%s'", key, val);
udev_add_property(udev, key, val);
}
} else {
log_error("wrong key format '%s'", key);
}
free(key);
}
worker_kill(udev);
}
i = udev_ctrl_get_set_children_max(ctrl_msg);
if (i >= 0) {
log_debug("udevd message (SET_MAX_CHILDREN) received, children_max=%i", i);
arg_children_max = i;
}
if (udev_ctrl_get_ping(ctrl_msg) > 0)
log_debug("udevd message (SYNC) received");
if (udev_ctrl_get_exit(ctrl_msg) > 0) {
log_debug("udevd message (EXIT) received");
udev_exit = true;
/* keep reference to block the client until we exit */
udev_ctrl_connection_ref(ctrl_conn);
}
out:
udev_ctrl_msg_unref(ctrl_msg);
return udev_ctrl_connection_unref(ctrl_conn);
}
static int synthesize_change(struct udev_device *dev) {
char filename[UTIL_PATH_SIZE];
int r;
if (streq_ptr("block", udev_device_get_subsystem(dev)) &&
streq_ptr("disk", udev_device_get_devtype(dev)) &&
!startswith(udev_device_get_sysname(dev), "dm-")) {
bool part_table_read = false;
bool has_partitions = false;
int fd;
struct udev *udev = udev_device_get_udev(dev);
_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
struct udev_list_entry *item;
/*
* Try to re-read the partition table. This only succeeds if
* none of the devices is busy. The kernel returns 0 if no
* partition table is found, and we will not get an event for
* the disk.
*/
fd = open(udev_device_get_devnode(dev), O_RDONLY|O_CLOEXEC|O_NOFOLLOW|O_NONBLOCK);
if (fd >= 0) {
r = flock(fd, LOCK_EX|LOCK_NB);
if (r >= 0)
r = ioctl(fd, BLKRRPART, 0);
close(fd);
if (r >= 0)
part_table_read = true;
}
/* search for partitions */
e = udev_enumerate_new(udev);
if (!e)
return -ENOMEM;
r = udev_enumerate_add_match_parent(e, dev);
if (r < 0)
return r;
r = udev_enumerate_add_match_subsystem(e, "block");
if (r < 0)
return r;
r = udev_enumerate_scan_devices(e);
if (r < 0)
return r;
udev_list_entry_foreach(item, udev_enumerate_get_list_entry(e)) {
_cleanup_udev_device_unref_ struct udev_device *d = NULL;
d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
if (!d)
continue;
if (!streq_ptr("partition", udev_device_get_devtype(d)))
continue;
has_partitions = true;
break;
}
/*
* We have partitions and re-read the table, the kernel already sent
* out a "change" event for the disk, and "remove/add" for all
* partitions.
*/
if (part_table_read && has_partitions)
return 0;
/*
* We have partitions but re-reading the partition table did not
* work, synthesize "change" for the disk and all partitions.
*/
log_debug("device %s closed, synthesising 'change'", udev_device_get_devnode(dev));
strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
write_string_file(filename, "change");
udev_list_entry_foreach(item, udev_enumerate_get_list_entry(e)) {
_cleanup_udev_device_unref_ struct udev_device *d = NULL;
d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
if (!d)
continue;
if (!streq_ptr("partition", udev_device_get_devtype(d)))
continue;
log_debug("device %s closed, synthesising partition '%s' 'change'",
udev_device_get_devnode(dev), udev_device_get_devnode(d));
strscpyl(filename, sizeof(filename), udev_device_get_syspath(d), "/uevent", NULL);
write_string_file(filename, "change");
}
return 0;
}
log_debug("device %s closed, synthesising 'change'", udev_device_get_devnode(dev));
strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
write_string_file(filename, "change");
return 0;
}
static int handle_inotify(struct udev *udev) {
int nbytes, pos;
char *buf;
struct inotify_event *ev;
int r;
r = ioctl(fd_inotify, FIONREAD, &nbytes);
if (r < 0 || nbytes <= 0)
return -errno;
buf = malloc(nbytes);
if (!buf) {
log_error("error getting buffer for inotify");
return -ENOMEM;
}
nbytes = read(fd_inotify, buf, nbytes);
for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
struct udev_device *dev;
ev = (struct inotify_event *)(buf + pos);
dev = udev_watch_lookup(udev, ev->wd);
if (!dev)
continue;
log_debug("inotify event: %x for %s", ev->mask, udev_device_get_devnode(dev));
if (ev->mask & IN_CLOSE_WRITE)
synthesize_change(dev);
else if (ev->mask & IN_IGNORED)
udev_watch_end(udev, dev);
udev_device_unref(dev);
}
free(buf);
return 0;
}
static void handle_signal(struct udev *udev, int signo) {
switch (signo) {
case SIGINT:
case SIGTERM:
udev_exit = true;
break;
case SIGCHLD:
for (;;) {
pid_t pid;
int status;
struct udev_list_node *loop, *tmp;
pid = waitpid(-1, &status, WNOHANG);
if (pid <= 0)
break;
udev_list_node_foreach_safe(loop, tmp, &worker_list) {
struct worker *worker = node_to_worker(loop);
if (worker->pid != pid)
continue;
log_debug("worker [%u] exit", pid);
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) != 0)
log_error("worker [%u] exit with return code %i",
pid, WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
log_error("worker [%u] terminated by signal %i (%s)",
pid, WTERMSIG(status), strsignal(WTERMSIG(status)));
} else if (WIFSTOPPED(status)) {
log_error("worker [%u] stopped", pid);
} else if (WIFCONTINUED(status)) {
log_error("worker [%u] continued", pid);
} else {
log_error("worker [%u] exit with status 0x%04x", pid, status);
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
if (worker->event) {
log_error("worker [%u] failed while handling '%s'",
pid, worker->event->devpath);
worker->event->exitcode = -32;
event_queue_delete(worker->event);
/* drop reference taken for state 'running' */
worker_unref(worker);
}
}
worker_unref(worker);
break;
}
}
break;
case SIGHUP:
reload = true;
break;
}
}
static int systemd_fds(struct udev *udev, int *rctrl, int *rnetlink) {
int ctrl = -1, netlink = -1;
int fd, n;
n = sd_listen_fds(true);
if (n <= 0)
return -1;
for (fd = SD_LISTEN_FDS_START; fd < n + SD_LISTEN_FDS_START; fd++) {
if (sd_is_socket(fd, AF_LOCAL, SOCK_SEQPACKET, -1)) {
if (ctrl >= 0)
return -1;
ctrl = fd;
continue;
}
if (sd_is_socket(fd, AF_NETLINK, SOCK_RAW, -1)) {
if (netlink >= 0)
return -1;
netlink = fd;
continue;
}
return -1;
}
if (ctrl < 0 || netlink < 0)
return -1;
log_debug("ctrl=%i netlink=%i", ctrl, netlink);
*rctrl = ctrl;
*rnetlink = netlink;
return 0;
}
/*
* read the kernel command line, in case we need to get into debug mode
* udev.log-priority=<level> syslog priority
* udev.children-max=<number of workers> events are fully serialized if set to 1
* udev.exec-delay=<number of seconds> delay execution of every executed program
*/
static void kernel_cmdline_options(struct udev *udev) {
_cleanup_free_ char *line = NULL;
const char *word, *state;
size_t l;
int r;
r = proc_cmdline(&line);
if (r < 0) {
log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
return;
}
FOREACH_WORD_QUOTED(word, l, line, state) {
char *s, *opt, *value;
s = strndup(word, l);
if (!s)
break;
/* accept the same options for the initrd, prefixed with "rd." */
if (in_initrd() && startswith(s, "rd."))
opt = s + 3;
else
opt = s;
if ((value = startswith(opt, "udev.log-priority="))) {
int prio;
prio = util_log_priority(value);
log_set_max_level(prio);
} else if ((value = startswith(opt, "udev.children-max="))) {
r = safe_atoi(value, &arg_children_max);
if (r < 0)
log_warning("Invalid udev.children-max ignored: %s", value);
} else if ((value = startswith(opt, "udev.exec-delay="))) {
r = safe_atoi(value, &arg_exec_delay);
if (r < 0)
log_warning("Invalid udev.exec-delay ignored: %s", value);
} else if ((value = startswith(opt, "udev.event-timeout="))) {
r = safe_atou64(value, &arg_event_timeout_usec);
if (r < 0) {
log_warning("Invalid udev.event-timeout ignored: %s", value);
break;
}
arg_event_timeout_usec *= USEC_PER_SEC;
arg_event_timeout_warn_usec = (arg_event_timeout_usec / 3) ? : 1;
}
free(s);
}
}
static void help(void) {
printf("%s [OPTIONS...]\n\n"
"Manages devices.\n\n"
" --daemon\n"
" --debug\n"
" --children-max=<maximum number of workers>\n"
" --exec-delay=<seconds to wait before executing RUN=>\n"
" --event-timeout=<seconds to wait before terminating an event>\n"
" --resolve-names=early|late|never\n"
" --version\n"
" --help\n"
, program_invocation_short_name);
}
static int parse_argv(int argc, char *argv[]) {
static const struct option options[] = {
{ "daemon", no_argument, NULL, 'd' },
{ "debug", no_argument, NULL, 'D' },
{ "children-max", required_argument, NULL, 'c' },
{ "exec-delay", required_argument, NULL, 'e' },
{ "event-timeout", required_argument, NULL, 't' },
{ "resolve-names", required_argument, NULL, 'N' },
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
{}
};
int c;
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "c:de:DtN:hV", options, NULL)) >= 0) {
int r;
switch (c) {
case 'd':
arg_daemonize = true;
break;
case 'c':
r = safe_atoi(optarg, &arg_children_max);
if (r < 0)
log_warning("Invalid --children-max ignored: %s", optarg);
break;
case 'e':
r = safe_atoi(optarg, &arg_exec_delay);
if (r < 0)
log_warning("Invalid --exec-delay ignored: %s", optarg);
break;
case 't':
r = safe_atou64(optarg, &arg_event_timeout_usec);
if (r < 0)
log_warning("Invalid --event-timeout ignored: %s", optarg);
else {
arg_event_timeout_usec *= USEC_PER_SEC;
arg_event_timeout_warn_usec = (arg_event_timeout_usec / 3) ? : 1;
}
break;
case 'D':
arg_debug = true;
break;
case 'N':
if (streq(optarg, "early")) {
arg_resolve_names = 1;
} else if (streq(optarg, "late")) {
arg_resolve_names = 0;
} else if (streq(optarg, "never")) {
arg_resolve_names = -1;
} else {
log_error("resolve-names must be early, late or never");
return 0;
}
break;
case 'h':
help();
return 0;
case 'V':
printf("%s\n", VERSION);
return 0;
case '?':
return -EINVAL;
default:
assert_not_reached("Unhandled option");
}
}
return 1;
}
int main(int argc, char *argv[]) {
struct udev *udev;
sigset_t mask;
int fd_ctrl = -1;
int fd_netlink = -1;
int fd_worker = -1;
struct epoll_event ep_ctrl = { .events = EPOLLIN };
struct epoll_event ep_inotify = { .events = EPOLLIN };
struct epoll_event ep_signal = { .events = EPOLLIN };
struct epoll_event ep_netlink = { .events = EPOLLIN };
struct epoll_event ep_worker = { .events = EPOLLIN };
struct udev_ctrl_connection *ctrl_conn = NULL;
int rc = 1, r;
udev = udev_new();
if (udev == NULL)
goto exit;
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
r = parse_argv(argc, argv);
if (r <= 0)
goto exit;
kernel_cmdline_options(udev);
if (arg_debug)
log_set_max_level(LOG_DEBUG);
if (getuid() != 0) {
log_error("root privileges required");
goto exit;
}
r = mac_selinux_init("/dev");
if (r < 0) {
log_error("could not initialize labelling: %s", strerror(-r));
goto exit;
}
/* set umask before creating any file/directory */
r = chdir("/");
if (r < 0) {
log_error("could not change dir to /: %m");
goto exit;
}
umask(022);
r = mkdir("/run/udev", 0755);
if (r < 0 && errno != EEXIST) {
log_error("could not create /run/udev: %m");
goto exit;
}
dev_setup(NULL);
/* before opening new files, make sure std{in,out,err} fds are in a sane state */
if (arg_daemonize) {
int fd;
fd = open("/dev/null", O_RDWR);
if (fd >= 0) {
if (write(STDOUT_FILENO, 0, 0) < 0)
dup2(fd, STDOUT_FILENO);
if (write(STDERR_FILENO, 0, 0) < 0)
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO)
close(fd);
} else {
log_error("cannot open /dev/null");
}
}
if (systemd_fds(udev, &fd_ctrl, &fd_netlink) >= 0) {
/* get control and netlink socket from systemd */
udev_ctrl = udev_ctrl_new_from_fd(udev, fd_ctrl);
if (udev_ctrl == NULL) {
log_error("error taking over udev control socket");
rc = 1;
goto exit;
}
monitor = udev_monitor_new_from_netlink_fd(udev, "kernel", fd_netlink);
if (monitor == NULL) {
log_error("error taking over netlink socket");
rc = 3;
goto exit;
}
/* get our own cgroup, we regularly kill everything udev has left behind */
if (cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &udev_cgroup) < 0)
udev_cgroup = NULL;
} else {
/* open control and netlink socket */
udev_ctrl = udev_ctrl_new(udev);
if (udev_ctrl == NULL) {
log_error("error initializing udev control socket");
rc = 1;
goto exit;
}
fd_ctrl = udev_ctrl_get_fd(udev_ctrl);
monitor = udev_monitor_new_from_netlink(udev, "kernel");
if (monitor == NULL) {
log_error("error initializing netlink socket");
rc = 3;
goto exit;
}
fd_netlink = udev_monitor_get_fd(monitor);
}
if (udev_monitor_enable_receiving(monitor) < 0) {
log_error("error binding netlink socket");
rc = 3;
goto exit;
}
if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
log_error("error binding udev control socket");
rc = 1;
goto exit;
}
udev_monitor_set_receive_buffer_size(monitor, 128 * 1024 * 1024);
log_info("starting version " VERSION "\n");
udev_builtin_init(udev);
rules = udev_rules_new(udev, arg_resolve_names);
if (rules == NULL) {
log_error("error reading rules");
goto exit;
}
rc = udev_rules_apply_static_dev_perms(rules);
if (rc < 0)
log_error("failed to apply permissions on static device nodes - %s", strerror(-rc));
if (arg_daemonize) {
pid_t pid;
pid = fork();
switch (pid) {
case 0:
break;
case -1:
log_error("fork of daemon failed: %m");
rc = 4;
goto exit;
default:
rc = EXIT_SUCCESS;
goto exit_daemonize;
}
setsid();
write_string_file("/proc/self/oom_score_adj", "-1000");
} else {
sd_notify(1, "READY=1");
}
if (arg_children_max <= 0) {
cpu_set_t cpu_set;
arg_children_max = 8;
if (sched_getaffinity(0, sizeof (cpu_set), &cpu_set) == 0) {
arg_children_max += CPU_COUNT(&cpu_set) * 2;
}
}
log_debug("set children_max to %u", arg_children_max);
udev_list_node_init(&event_list);
udev_list_node_init(&worker_list);
fd_inotify = udev_watch_init(udev);
if (fd_inotify < 0) {
log_error("error initializing inotify");
rc = 4;
goto exit;
}
udev_watch_restore(udev);
/* block and listen to all signals on signalfd */
sigfillset(&mask);
sigprocmask(SIG_SETMASK, &mask, &sigmask_orig);
fd_signal = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
if (fd_signal < 0) {
log_error("error creating signalfd");
rc = 5;
goto exit;
}
/* unnamed socket from workers to the main daemon */
if (socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, worker_watch) < 0) {
log_error("error creating socketpair");
rc = 6;
goto exit;
}
fd_worker = worker_watch[READ_END];
ep_ctrl.data.fd = fd_ctrl;
ep_inotify.data.fd = fd_inotify;
ep_signal.data.fd = fd_signal;
ep_netlink.data.fd = fd_netlink;
ep_worker.data.fd = fd_worker;
fd_ep = epoll_create1(EPOLL_CLOEXEC);
if (fd_ep < 0) {
log_error("error creating epoll fd: %m");
goto exit;
}
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_ctrl, &ep_ctrl) < 0 ||
epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_inotify, &ep_inotify) < 0 ||
epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_signal, &ep_signal) < 0 ||
epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_netlink, &ep_netlink) < 0 ||
epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_worker, &ep_worker) < 0) {
log_error("fail to add fds to epoll: %m");
goto exit;
}
for (;;) {
static usec_t last_usec;
struct epoll_event ev[8];
int fdcount;
int timeout;
bool is_worker, is_signal, is_inotify, is_netlink, is_ctrl;
int i;
if (udev_exit) {
/* close sources of new events and discard buffered events */
if (fd_ctrl >= 0) {
epoll_ctl(fd_ep, EPOLL_CTL_DEL, fd_ctrl, NULL);
fd_ctrl = -1;
}
if (monitor != NULL) {
epoll_ctl(fd_ep, EPOLL_CTL_DEL, fd_netlink, NULL);
udev_monitor_unref(monitor);
monitor = NULL;
}
if (fd_inotify >= 0) {
epoll_ctl(fd_ep, EPOLL_CTL_DEL, fd_inotify, NULL);
close(fd_inotify);
fd_inotify = -1;
}
/* discard queued events and kill workers */
event_queue_cleanup(udev, EVENT_QUEUED);
worker_kill(udev);
/* exit after all has cleaned up */
if (udev_list_node_is_empty(&event_list) && children == 0)
break;
/* timeout at exit for workers to finish */
timeout = 30 * MSEC_PER_SEC;
} else if (udev_list_node_is_empty(&event_list) && children == 0) {
/* we are idle */
timeout = -1;
/* cleanup possible left-over processes in our cgroup */
if (udev_cgroup)
cg_kill(SYSTEMD_CGROUP_CONTROLLER, udev_cgroup, SIGKILL, false, true, NULL);
} else {
/* kill idle or hanging workers */
timeout = 3 * MSEC_PER_SEC;
}
/* tell settle that we are busy or idle */
if (!udev_list_node_is_empty(&event_list)) {
int fd;
fd = open("/run/udev/queue", O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
if (fd >= 0)
close(fd);
} else {
unlink("/run/udev/queue");
}
fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), timeout);
if (fdcount < 0)
continue;
if (fdcount == 0) {
struct udev_list_node *loop;
/* timeout */
if (udev_exit) {
log_error("timeout, giving up waiting for workers to finish");
break;
}
/* kill idle workers */
if (udev_list_node_is_empty(&event_list)) {
log_debug("cleanup idle workers");
worker_kill(udev);
}
/* check for hanging events */
udev_list_node_foreach(loop, &worker_list) {
struct worker *worker = node_to_worker(loop);
usec_t ts;
if (worker->state != WORKER_RUNNING)
continue;
ts = now(CLOCK_MONOTONIC);
if ((ts - worker->event_start_usec) > arg_event_timeout_warn_usec) {
if ((ts - worker->event_start_usec) > arg_event_timeout_usec) {
log_error("worker [%u] %s timeout; kill it", worker->pid, worker->event->devpath);
kill(worker->pid, SIGKILL);
worker->state = WORKER_KILLED;
/* drop reference taken for state 'running' */
worker_unref(worker);
log_error("seq %llu '%s' killed", udev_device_get_seqnum(worker->event->dev), worker->event->devpath);
worker->event->exitcode = -64;
event_queue_delete(worker->event);
worker->event = NULL;
} else if (!worker->event_warned) {
log_warning("worker [%u] %s is taking a long time", worker->pid, worker->event->devpath);
worker->event_warned = true;
}
}
}
}
is_worker = is_signal = is_inotify = is_netlink = is_ctrl = false;
for (i = 0; i < fdcount; i++) {
if (ev[i].data.fd == fd_worker && ev[i].events & EPOLLIN)
is_worker = true;
else if (ev[i].data.fd == fd_netlink && ev[i].events & EPOLLIN)
is_netlink = true;
else if (ev[i].data.fd == fd_signal && ev[i].events & EPOLLIN)
is_signal = true;
else if (ev[i].data.fd == fd_inotify && ev[i].events & EPOLLIN)
is_inotify = true;
else if (ev[i].data.fd == fd_ctrl && ev[i].events & EPOLLIN)
is_ctrl = true;
}
/* check for changed config, every 3 seconds at most */
if ((now(CLOCK_MONOTONIC) - last_usec) > 3 * USEC_PER_SEC) {
if (udev_rules_check_timestamp(rules))
reload = true;
if (udev_builtin_validate(udev))
reload = true;
last_usec = now(CLOCK_MONOTONIC);
}
/* reload requested, HUP signal received, rules changed, builtin changed */
if (reload) {
worker_kill(udev);
rules = udev_rules_unref(rules);
udev_builtin_exit(udev);
reload = false;
}
/* event has finished */
if (is_worker)
worker_returned(fd_worker);
if (is_netlink) {
struct udev_device *dev;
dev = udev_monitor_receive_device(monitor);
if (dev != NULL) {
udev_device_set_usec_initialized(dev, now(CLOCK_MONOTONIC));
if (event_queue_insert(dev) < 0)
udev_device_unref(dev);
}
}
/* start new events */
if (!udev_list_node_is_empty(&event_list) && !udev_exit && !stop_exec_queue) {
udev_builtin_init(udev);
if (rules == NULL)
rules = udev_rules_new(udev, arg_resolve_names);
if (rules != NULL)
event_queue_start(udev);
}
if (is_signal) {
struct signalfd_siginfo fdsi;
ssize_t size;
size = read(fd_signal, &fdsi, sizeof(struct signalfd_siginfo));
if (size == sizeof(struct signalfd_siginfo))
handle_signal(udev, fdsi.ssi_signo);
}
/* we are shutting down, the events below are not handled anymore */
if (udev_exit)
continue;
/* device node watch */
if (is_inotify)
handle_inotify(udev);
/*
* This needs to be after the inotify handling, to make sure,
* that the ping is send back after the possibly generated
* "change" events by the inotify device node watch.
*
* A single time we may receive a client connection which we need to
* keep open to block the client. It will be closed right before we
* exit.
*/
if (is_ctrl)
ctrl_conn = handle_ctrl_msg(udev_ctrl);
}
rc = EXIT_SUCCESS;
exit:
udev_ctrl_cleanup(udev_ctrl);
unlink("/run/udev/queue");
exit_daemonize:
if (fd_ep >= 0)
close(fd_ep);
worker_list_cleanup(udev);
event_queue_cleanup(udev, EVENT_UNDEF);
udev_rules_unref(rules);
udev_builtin_exit(udev);
if (fd_signal >= 0)
close(fd_signal);
if (worker_watch[READ_END] >= 0)
close(worker_watch[READ_END]);
if (worker_watch[WRITE_END] >= 0)
close(worker_watch[WRITE_END]);
udev_monitor_unref(monitor);
udev_ctrl_connection_unref(ctrl_conn);
udev_ctrl_unref(udev_ctrl);
mac_selinux_finish();
udev_unref(udev);
log_close();
return rc;
}
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