X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udevd.c;h=395cdca88baba503e39488c116b587f7196a7025;hb=5a73b25fd6673134328443af04afe7bde0060d72;hp=8ba833186e100bb3958acb0d0c6b2ff6e81beae1;hpb=2f6cbd19113167746dc4fb6b4f3f5fd64a1c211f;p=elogind.git diff --git a/udevd.c b/udevd.c index 8ba833186..395cdca88 100644 --- a/udevd.c +++ b/udevd.c @@ -28,42 +28,62 @@ #include #include #include -#include +#include #include #include #include -#include +#include +#include +#include #include "list.h" #include "udev.h" +#include "udev_lib.h" #include "udev_version.h" #include "udevd.h" #include "logging.h" -unsigned char logname[42]; -static int expected_seqnum = 0; -volatile static int children_waiting; -volatile static int msg_q_timeout; +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; -LIST_HEAD(msg_list); -LIST_HEAD(exec_list); -LIST_HEAD(running_list); +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; -static void msg_dump_queue(void) +#ifdef LOG +unsigned char logname[LOGNAME_SIZE]; +void log_message (int level, const char *format, ...) { - struct hotplug_msg *msg; + va_list args; - list_for_each_entry(msg, &msg_list, list) - dbg("sequence %d in queue", msg->seqnum); + va_start(args, format); + vsyslog(level, format, args); + va_end(args); } +#endif -static void msg_dump(struct hotplug_msg *msg) +#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) { - dbg("sequence %d, '%s', '%s', '%s'", - msg->seqnum, msg->action, msg->devpath, msg->subsystem); +#ifdef DEBUG + struct hotplug_msg *msg; + + list_for_each_entry(msg, &msg_list, list) + dbg("sequence %llu in queue", msg->seqnum); +#endif } static struct hotplug_msg *msg_create(void) @@ -80,26 +100,30 @@ static void run_queue_delete(struct hotplug_msg *msg) { list_del(&msg->list); free(msg); - exec_queue_manager(); } /* 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); /* run msg queue manager */ - msg_queue_manager(); + run_msg_q = 1; return ; } @@ -108,24 +132,35 @@ static void msg_queue_insert(struct hotplug_msg *msg) static void udev_run(struct hotplug_msg *msg) { pid_t pid; - setenv("ACTION", msg->action, 1); - setenv("DEVPATH", msg->devpath, 1); + char action[ACTION_SIZE]; + char devpath[DEVPATH_SIZE]; + char seqnum[SEQNUM_SIZE]; + char *env[] = { action, devpath, seqnum, NULL }; + + snprintf(action, ACTION_SIZE-1, "ACTION=%s", msg->action); + action[ACTION_SIZE-1] = '\0'; + snprintf(devpath, DEVPATH_SIZE-1, "DEVPATH=%s", msg->devpath); + devpath[DEVPATH_SIZE-1] = '\0'; + sprintf(seqnum, "SEQNUM=%llu", msg->seqnum); pid = fork(); switch (pid) { case 0: /* child */ - execl(UDEV_BIN, "udev", msg->subsystem, NULL); + execle(udev_bin, "udev", msg->subsystem, NULL, env); dbg("exec of child failed"); - exit(1); + _exit(1); break; case -1: dbg("fork of child failed"); 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: /* get SIGCHLD in main loop */ - dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath); + dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath); msg->pid = pid; } } @@ -141,7 +176,7 @@ static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg) } /* exec queue management routine executes the events and delays events for the same devpath */ -static void exec_queue_manager() +static void exec_queue_manager(void) { struct hotplug_msg *loop_msg; struct hotplug_msg *tmp_msg; @@ -153,9 +188,9 @@ static void exec_queue_manager() /* move event to run list */ list_move_tail(&loop_msg->list, &running_list); udev_run(loop_msg); - dbg("moved seq %d to running list", loop_msg->seqnum); + dbg("moved seq %llu to running list", loop_msg->seqnum); } else { - dbg("delay seq %d, cause seq %d already working on '%s'", + dbg("delay seq %llu, cause seq %llu already working on '%s'", loop_msg->seqnum, msg->seqnum, msg->devpath); } } @@ -164,20 +199,21 @@ static void exec_queue_manager() static void msg_move_exec(struct hotplug_msg *msg) { list_move_tail(&msg->list, &exec_list); - exec_queue_manager(); + run_exec_q = 1; expected_seqnum = msg->seqnum+1; - dbg("moved seq %d to exec, next expected is %d", + dbg("moved seq %llu to exec, next expected is %llu", msg->seqnum, expected_seqnum); } /* msg queue management routine handles the timeouts and dispatches the events */ -static void msg_queue_manager() +static void msg_queue_manager(void) { struct hotplug_msg *loop_msg; struct hotplug_msg *tmp_msg; - time_t msg_age = 0; + struct sysinfo info; + long msg_age = 0; - dbg("msg queue manager, next expected is %d", expected_seqnum); + 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 */ @@ -187,7 +223,9 @@ recheck: } /* move event with expired timeout to the exec list */ - msg_age = time(NULL) - loop_msg->queue_time; + 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; @@ -198,12 +236,11 @@ recheck: msg_dump_queue(); + /* set timeout for remaining queued events */ if (list_empty(&msg_list) == 0) { - /* set timeout for remaining queued events */ 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, 0); + dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age); + setitimer(ITIMER_REAL, &itv, NULL); } } @@ -212,6 +249,11 @@ static void handle_msg(int sock) { struct hotplug_msg *msg; int retval; + struct msghdr smsg; + struct cmsghdr *cmsg; + struct iovec iov; + struct ucred *cred; + char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; msg = msg_create(); if (msg == NULL) { @@ -219,43 +261,82 @@ static void handle_msg(int sock) return; } - retval = recv(sock, msg, sizeof(struct hotplug_msg), 0); + iov.iov_base = msg; + iov.iov_len = sizeof(struct hotplug_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); + + retval = recvmsg(sock, &smsg, 0); if (retval < 0) { if (errno != EINTR) dbg("unable to receive message"); return; } - + cmsg = CMSG_FIRSTHDR(&smsg); + cred = (struct ucred *) CMSG_DATA(cmsg); + + if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { + dbg("no sender credentials received, message ignored"); + goto skip; + } + + if (cred->uid != 0) { + dbg("sender uid=%i, message ignored", cred->uid); + goto skip; + } + if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) { dbg("message magic '%s' doesn't match, ignore it", msg->magic); - free(msg); - return; + goto skip; } /* if no seqnum is given, we move straight to exec queue */ - if (msg->seqnum == -1) { + if (msg->seqnum == 0) { list_add(&msg->list, &exec_list); - exec_queue_manager(); + run_exec_q = 1; } else { msg_queue_insert(msg); } + return; + +skip: + free(msg); + return; } -static void sig_handler(int signum) +static void asmlinkage sig_handler(int signum) { + int rc; + switch (signum) { case SIGINT: case SIGTERM: exit(20 + signum); break; case SIGALRM: - msg_q_timeout = 1; + /* set flag, then write to pipe if needed */ + run_msg_q = 1; + goto do_write; break; case SIGCHLD: - children_waiting = 1; + /* set flag, then write to pipe if needed */ + sigchilds_waiting = 1; + goto do_write; break; - default: - dbg("unhandled signal"); + } + +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; } } @@ -266,30 +347,118 @@ static void udev_done(int pid) list_for_each_entry(msg, &running_list, list) { if (msg->pid == pid) { - dbg("<== exec seq %d came back", msg->seqnum); + 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; } } } -int main(int argc, char *argv[]) +static void reap_sigchilds(void) +{ + while(1) { + int pid = waitpid(-1, NULL, WNOHANG); + if ((pid == -1) || (pid == 0)) + break; + udev_done(pid); + } +} + +/* 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; + + sig_flag = 0; + } +} + +int main(int argc, char *argv[], char *envp[]) { - int ssock; + int ssock, maxsockplus; struct sockaddr_un saddr; socklen_t addrlen; - int retval; + int retval, fd; + const int feature_on = 1; + struct sigaction act; + fd_set readfds; + + logging_init("udevd"); + dbg("version %s", UDEV_VERSION); + + if (getuid() != 0) { + dbg("need to be root, exit"); + _exit(1); + } + + /* make sure we don't lock any path */ + chdir("/"); + umask(umask(077) | 022); - init_logging("udevd"); + /* Set fds to dev/null */ + fd = open( "/dev/null", O_RDWR ); + if ( fd < 0 ) { + dbg("error opening /dev/null %s", strerror(errno)); + exit(1); + } + dup2(fd, 0); + dup2(fd, 1); + dup2(fd, 2); + if (fd > 2) + close(fd); + + /* become session leader */ + setsid(); - signal(SIGINT, sig_handler); - signal(SIGTERM, sig_handler); - signal(SIGALRM, sig_handler); - signal(SIGCHLD, sig_handler); + /* setup signal handler pipe */ + retval = pipe(pipefds); + if (retval < 0) { + dbg("error getting pipes: %s", strerror(errno)); + exit(1); + } - /* we want these two to interrupt system calls */ - siginterrupt(SIGALRM, 1); - siginterrupt(SIGCHLD, 1); + retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK); + if (retval < 0) { + dbg("error fcntl on read pipe: %s", strerror(errno)); + exit(1); + } + retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC); + if (retval < 0) { + dbg("error fcntl on read pipe: %s", strerror(errno)); + exit(1); + } + + retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK); + if (retval < 0) { + dbg("error fcntl on write pipe: %s", strerror(errno)); + exit(1); + } + retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC); + if (retval < 0) { + dbg("error fcntl on write pipe: %s", strerror(errno)); + exit(1); + } + + /* 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; @@ -299,37 +468,77 @@ int main(int argc, char *argv[]) ssock = socket(AF_LOCAL, SOCK_DGRAM, 0); if (ssock == -1) { - dbg("error getting socket"); + dbg("error getting socket, exit"); exit(1); } + set_cloexec_flag(ssock, 1); + /* the bind takes care of ensuring only one copy running */ - retval = bind(ssock, &saddr, addrlen); + retval = bind(ssock, (struct sockaddr *) &saddr, addrlen); if (retval < 0) { - dbg("bind failed\n"); + dbg("bind failed, exit"); goto exit; } + retval = fcntl(ssock, F_SETFD, FD_CLOEXEC); + if (retval < 0) { + dbg("error fcntl on ssock: %s", strerror(errno)); + exit(1); + } + + /* enable receiving of the sender credentials */ + setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on)); + /* 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; + + FD_ZERO(&readfds); + FD_SET(ssock, &readfds); + FD_SET(pipefds[0], &readfds); + maxsockplus = ssock+1; while (1) { - handle_msg(ssock); + 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(ssock, &workreadfds)) + handle_msg(ssock); - while(msg_q_timeout) { - msg_q_timeout = 0; + 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(); } - while(children_waiting) { - children_waiting = 0; - /* reap all dead children */ - while(1) { - int pid = waitpid(-1, 0, WNOHANG); - if ((pid == -1) || (pid == 0)) - break; - udev_done(pid); + 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(); } } exit: close(ssock); - exit(1); + logging_close(); + return 1; }