X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=58f5be94bc42c43f368e1fe9665e5f34d861ab2b;hp=22fb4d33db86d8e387d3d0ff2000f6f1d2de1d0b;hb=4497fcbf7159975560b680fd8130adcd414d3d67;hpb=53921bfa44129a19661a4aaa4c1647282921fc18 diff --git a/udevd.c b/udevd.c index 22fb4d33d..58f5be94b 100644 --- a/udevd.c +++ b/udevd.c @@ -2,6 +2,7 @@ * udevd.c - hotplug event serializer * * Copyright (C) 2004 Kay Sievers + * Copyright (C) 2004 Chris Friesen * * * This program is free software; you can redistribute it and/or modify it @@ -20,7 +21,6 @@ */ #include -#include #include #include #include @@ -28,385 +28,533 @@ #include #include #include -#include -#include +#include #include #include #include -#include +#include +#include +#include #include "list.h" #include "udev.h" #include "udev_version.h" +#include "udev_utils.h" #include "udevd.h" #include "logging.h" +/* global variables*/ +static int udevsendsock; + +static int pipefds[2]; +static unsigned long long expected_seqnum = 0; +static volatile int sigchilds_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_sigchilds(void); +char *udev_bin; + +#ifdef LOG +unsigned char logname[LOGNAME_SIZE]; +void log_message (int level, const char *format, ...) +{ + va_list args; -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); + va_start(args, format); + vsyslog(level, format, args); + va_end(args); +} +#endif +#define msg_dump(msg) \ + dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \ + msg->seqnum, msg->action, msg->devpath, msg->subsystem); static void msg_dump_queue(void) { +#ifdef DEBUG 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); + dbg("sequence %llu in queue", msg->seqnum); +#endif } -/* allocates a new message */ -static struct hotplug_msg *msg_create(void) +static void run_queue_delete(struct hotplug_msg *msg) { - struct hotplug_msg *new_msg; - - new_msg = malloc(sizeof(struct hotplug_msg)); - if (new_msg == NULL) { - dbg("error malloc"); - return NULL; - } - memset(new_msg, 0x00, sizeof(struct hotplug_msg)); - return new_msg; + list_del(&msg->list); + 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; + struct sysinfo info; - /* sort message by sequence number into list*/ - list_for_each_entry(loop_msg, &msg_list, list) - if (loop_msg->seqnum > msg->seqnum) + /* 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; - list_add_tail(&msg->list, &loop_msg->list); - dbg("queued message seq %d", msg->seqnum); /* store timestamp of queuing */ - msg->queue_time = time(NULL); + sysinfo(&info); + msg->queue_time = info.uptime; + + list_add(&msg->list, &loop_msg->list); + dbg("queued message seq %llu", msg->seqnum); - /* signal queue activity to manager */ - pthread_mutex_lock(&msg_active_lock); - pthread_cond_signal(&msg_active); - pthread_mutex_unlock(&msg_active_lock); + /* run msg queue manager */ + run_msg_q = 1; return ; } /* forks event and removes event from run queue when finished */ -static void *run_threads(void * parm) +static void udev_run(struct hotplug_msg *msg) { + char *const argv[] = { "udev", msg->subsystem, NULL }; 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); + close(udevsendsock); + logging_close(); + execve(udev_bin, argv, msg->envp); dbg("exec of child failed"); - exit(1); + _exit(1); break; case -1: dbg("fork of child failed"); - goto exit; + 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 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); + /* get SIGCHLD in main loop */ + dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath); + msg->pid = pid; } - -exit: - /* remove event from run list */ - pthread_mutex_lock(&running_lock); - list_del_init(&msg->list); - pthread_mutex_unlock(&running_lock); - - free(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(loop_msg, &running_list, list) { + if (loop_msg->devpath == NULL || msg->devpath == NULL) + continue; - list_for_each_entry_safe(loop_msg, tmp_msg, &running_list, list) - if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0) + if (strcmp(loop_msg->devpath, 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) +/* exec queue management routine executes the events and delays events for the same devpath */ +static void exec_queue_manager(void) { 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); - } + 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); } - 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) +static void msg_move_exec(struct hotplug_msg *msg) { - 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); + 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); } -/* queue management thread handles the timeouts and dispatches the events */ -static void *msg_queue_manager(void * parm) +/* msg queue management routine handles the timeouts and dispatches the events */ +static void msg_queue_manager(void) { struct hotplug_msg *loop_msg; struct hotplug_msg *tmp_msg; - time_t msg_age = 0; - struct timespec tv; + struct sysinfo info; + long msg_age = 0; - while (1) { - dbg("msg queue manager, next expected is %d", expected_seqnum); - pthread_mutex_lock(&msg_lock); - pthread_mutex_lock(&exec_lock); + dbg("msg queue manager, next expected is %llu", expected_seqnum); 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; - } + 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; } - 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); + /* 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 { - pthread_cond_wait(&msg_active, &msg_active_lock); + break; } - pthread_mutex_unlock(&msg_active_lock); + } + + 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, NULL); } } -/* every connect creates a thread which gets the msg, queues it and exits */ -static void *client_threads(void * parm) +/* receive the msg, do some basic sanity checks, and queue it */ +static void handle_udevsend_msg(int sock) { - int sock; + static struct udevsend_msg usend_msg; struct hotplug_msg *msg; - int retval; - - sock = (int) parm; + int bufpos; + int i; + 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; + + memset(&usend_msg, 0x00, sizeof(struct udevsend_msg)); + iov.iov_base = &usend_msg; + iov.iov_len = sizeof(struct udevsend_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(sock, &smsg, 0); + if (size < 0) { + if (errno != EINTR) + dbg("unable to receive message"); + return; + } + cmsg = CMSG_FIRSTHDR(&smsg); + cred = (struct ucred *) CMSG_DATA(cmsg); - msg = msg_create(); - if (msg == NULL) { - dbg("unable to store message"); + if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { + dbg("no sender credentials received, message ignored"); goto exit; } - retval = recv(sock, msg, sizeof(struct hotplug_msg), 0); - if (retval < 0) { - dbg("unable to receive message"); + if (cred->uid != 0) { + dbg("sender uid=%i, message ignored", cred->uid); goto exit; } - if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) { - dbg("message magic '%s' doesn't match, ignore it", msg->magic); + if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) { + dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic); goto exit; } - pthread_mutex_lock(&msg_lock); - msg_queue_insert(msg); - pthread_mutex_unlock(&msg_lock); + envbuf_size = size - offsetof(struct udevsend_msg, envbuf); + dbg("envbuf_size=%i", envbuf_size); + msg = malloc(sizeof(struct hotplug_msg) + envbuf_size); + memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size); + + /* copy environment buffer and reconstruct envp */ + memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size); + bufpos = 0; + for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_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]; + + if (strncmp(key, "DEVPATH=", 8) == 0) + msg->devpath = &key[8]; + + if (strncmp(key, "SUBSYSTEM=", 10) == 0) + msg->subsystem = &key[10]; + + if (strncmp(key, "SEQNUM=", 7) == 0) + msg->seqnum = strtoull(&key[7], NULL, 10); + } + msg->envp[i++] = "MANAGED_EVENT=1"; + msg->envp[i] = NULL; + + /* 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); + } exit: - close(sock); - pthread_exit(0); + return; } -static void sig_handler(int signum) +static void asmlinkage sig_handler(int signum) { + int rc; + switch (signum) { case SIGINT: case SIGTERM: - unlink(UDEVD_LOCK); - unlink(UDEVD_SOCKET); exit(20 + signum); break; - default: - dbg("unhandled signal"); + 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 */ + sigchilds_waiting = 1; + goto do_write; + break; + } + +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) + sig_flag = 1; + } +} + +static void udev_done(int pid) +{ + /* find msg associated with pid and delete it */ + struct hotplug_msg *msg; + + 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; + } } } -static int one_and_only(void) +static void reap_sigchilds(void) { - char string[50]; - int lock_file; - - /* see if we can open */ - 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; + while(1) { + int pid = waitpid(-1, NULL, 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 flags was set in the signal handler + */ +static void user_sighandler(void) +{ + 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[]) +int main(int argc, char *argv[], char *envp[]) { - int ssock; - int csock; + int maxsockplus; 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; + socklen_t addrlen; + int retval, fd; + const int feature_on = 1; + struct sigaction act; + fd_set readfds; - /* only let one version of the daemon run at any one time */ - if (one_and_only() != 0) - exit(0); + logging_init("udevd"); + dbg("version %s", UDEV_VERSION); - signal(SIGINT, sig_handler); - signal(SIGTERM, sig_handler); + if (getuid() != 0) { + dbg("need to be root, exit"); + goto exit; + } - memset(&saddr, 0x00, sizeof(saddr)); - saddr.sun_family = AF_LOCAL; - strcpy(saddr.sun_path, UDEVD_SOCKET); + /* make sure we don't lock any path */ + chdir("/"); + umask(umask(077) | 022); - unlink(UDEVD_SOCKET); - ssock = socket(AF_LOCAL, SOCK_STREAM, 0); - if (ssock == -1) { - dbg("error getting socket"); - exit(1); + /* Set fds to dev/null */ + fd = open( "/dev/null", O_RDWR ); + if ( fd < 0 ) { + dbg("error opening /dev/null %s", strerror(errno)); + goto exit; } + dup2(fd, 0); + dup2(fd, 1); + dup2(fd, 2); + if (fd > 2) + close(fd); + + /* become session leader */ + setsid(); - retval = bind(ssock, &saddr, sizeof(saddr)); + /* setup signal handler pipe */ + retval = pipe(pipefds); if (retval < 0) { - dbg("bind failed\n"); + dbg("error getting pipes: %s", strerror(errno)); goto exit; } - retval = listen(ssock, SOMAXCONN); + retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK); if (retval < 0) { - dbg("listen failed\n"); + dbg("error fcntl on read pipe: %s", strerror(errno)); + goto exit; + } + retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC); + if (retval < 0) { + dbg("error fcntl on read pipe: %s", strerror(errno)); 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); + retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK); + if (retval < 0) { + dbg("error fcntl on write pipe: %s", strerror(errno)); + goto exit; + } + retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC); + if (retval < 0) { + dbg("error fcntl on write pipe: %s", strerror(errno)); + goto exit; + } + + /* set signal handlers */ + 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(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; + + udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0); + if (udevsendsock == -1) { + dbg("error getting socket, exit"); + goto exit; + } + + /* the bind takes care of ensuring only one copy running */ + retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen); + if (retval < 0) { + dbg("bind failed, exit"); + close(udevsendsock); + goto exit; + } - /* set default attributes for created threads */ - pthread_attr_init(&thr_attr); - pthread_attr_setdetachstate(&thr_attr, PTHREAD_CREATE_DETACHED); + /* enable receiving of the sender credentials */ + setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on)); - /* 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); + /* 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; - clen = sizeof(caddr); - /* main loop */ + FD_ZERO(&readfds); + FD_SET(udevsendsock, &readfds); + FD_SET(pipefds[0], &readfds); + maxsockplus = udevsendsock+1; while (1) { - csock = accept(ssock, &caddr, &clen); - if (csock < 0) { - if (errno == EINTR) - continue; - dbg("client accept failed\n"); + 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(udevsendsock, &workreadfds)) + handle_udevsend_msg(udevsendsock); + + if (FD_ISSET(pipefds[0], &workreadfds)) + user_sighandler(); + + if (sigchilds_waiting) { + sigchilds_waiting = 0; + reap_sigchilds(); + } + + if (run_msg_q) { + run_msg_q = 0; + msg_queue_manager(); + } + + if (run_exec_q) { + /* clean up running_list before calling exec_queue_manager() */ + if (sigchilds_waiting) { + sigchilds_waiting = 0; + reap_sigchilds(); + } + + run_exec_q = 0; + exec_queue_manager(); } - pthread_create(&cli_tid, &thr_attr, client_threads, (void *) csock); } + exit: - close(ssock); - unlink(UDEVD_SOCKET); - exit(1); + logging_close(); + return 1; }