/* * udevd.c - event listener and serializer * * Copyright (C) 2004-2005 Kay Sievers * Copyright (C) 2004 Chris Friesen * * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "list.h" #include "udev_libc_wrapper.h" #include "udev.h" #include "udev_version.h" #include "udev_rules.h" #include "udev_utils.h" #include "udevd.h" #include "logging.h" /* global variables*/ 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 msg_queue_insert(struct uevent_msg *msg) { list_add(&msg->node, &exec_list); msg->queue_time = time(NULL); run_exec_q = 1; } static void msg_queue_delete(struct uevent_msg *msg) { list_del(&msg->node); free(msg); } 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; struct name_entry *name_loop; 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 env from message */ for (i = 0; msg->envp[i]; i++) putenv(msg->envp[i]); udev_init_device(&udev, msg->devpath, msg->subsystem, msg->action); retval = udev_process_event(&rules, &udev); /* run programs collected by RUN-key*/ if (!retval) { 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 run_program(name_loop->name, udev.subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO)); } } udev_cleanup_device(&udev); return 0; } /* runs event and removes event from run queue when finished */ static void udev_event_run(struct uevent_msg *msg) { pid_t pid; 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); udev_event_process(msg); info("seq %llu finished", msg->seqnum); logging_close(); exit(0); case -1: err("fork of child failed"); 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 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; if (msg->devpath == NULL) return 0; /* skip any events with a timeout set */ if (msg->timeout != 0) return 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; } if (loop_msg->devpath == NULL) continue; /* 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 exec_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, cause too many processes already running", loop_msg->seqnum); return; } } if (running_with_devpath(loop_msg, max_childs) == 0) { /* 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); } else dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath); } } 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; 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 udevd message"); 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; exec_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 udevd message"); 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) { /* find msg associated with pid and delete it */ struct uevent_msg *msg; list_for_each_entry(msg, &running_list, node) { if (msg->pid == pid) { if (msg->queue_time) info("seq %llu, pid [%d] exit, %ld seconds old", msg->seqnum, msg->pid, time(NULL) - msg->queue_time); else info("seq 0, pid [%d] exit", msg->pid); msg_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 void reap_sigchilds(void) { pid_t pid; while (1) { pid = waitpid(-1, NULL, WNOHANG); if (pid <= 0) break; udev_done(pid); } } 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"); udev_init_config(); 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) { dbg("another udevd running, exit"); rc = 1; } else { dbg("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 */ 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"); 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"); 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) dbg("error in select: %s", strerror(errno)); continue; } /* get user socket message */ if (FD_ISSET(udevd_sock, &readfds)) { msg = get_udevd_msg(); if (msg) { if (msg->type == UDEVD_UEVENT_UDEVSEND && msg->seqnum != 0) { info("skip non-kernel message with SEQNUM"); free(msg); } else 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_close(&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) exec_queue_manager(); } } exit: udev_rules_close(&rules); 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; }