X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=79de11248ec5e8db484ce31318916d446af6353a;hp=8ba833186e100bb3958acb0d0c6b2ff6e81beae1;hb=807755776d294a9811c0c8e835538e83abf734bc;hpb=2f6cbd19113167746dc4fb6b4f3f5fd64a1c211f diff --git a/udevd.c b/udevd.c index 8ba833186..79de11248 100644 --- a/udevd.c +++ b/udevd.c @@ -28,42 +28,62 @@ #include #include #include -#include +#include #include #include #include -#include +#include +#include "klibc_fixups.h" +#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 pipefds[2]; static int expected_seqnum = 0; volatile static int children_waiting; -volatile static int msg_q_timeout; +volatile static int run_msg_q; +volatile static 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_kids(void); +char *udev_bin; + +#ifdef LOG +unsigned char logname[LOGNAME_SIZE]; +void log_message (int level, const char *format, ...) +{ + va_list args; + + va_start(args, format); + vsyslog(level, format, args); + va_end(args); +} +#endif + +#define msg_dump(msg) \ + dbg("msg_dump: sequence %d, '%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); +#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 %d", msg->seqnum); /* run msg queue manager */ - msg_queue_manager(); + run_msg_q = 1; return ; } @@ -108,20 +132,29 @@ 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 *env[] = { action, devpath, NULL }; + + strcpy(action, "ACTION="); + strfieldcat(action, msg->action); + strcpy(devpath, "DEVPATH="); + strfieldcat(devpath, msg->devpath); 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); 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 */ @@ -164,7 +197,7 @@ 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", msg->seqnum, expected_seqnum); @@ -175,7 +208,8 @@ static void msg_queue_manager() { 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); recheck: @@ -187,7 +221,9 @@ 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 %d is %li seconds old", loop_msg->seqnum, msg_age); if (msg_age > EVENT_TIMEOUT_SEC-1) { msg_move_exec(loop_msg); goto recheck; @@ -198,11 +234,10 @@ 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); + dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age); setitimer(ITIMER_REAL, &itv, 0); } } @@ -212,6 +247,11 @@ 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 +259,87 @@ 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) { 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) +asmlinkage static void 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: + /* set flag, then write to pipe if needed */ children_waiting = 1; + goto do_write; break; default: - dbg("unhandled signal"); + dbg("unhandled signal %d", signum); + return; + } + +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) + dbg("unable to write to pipe"); + else + sig_flag = 1; } } @@ -268,28 +352,89 @@ static void udev_done(int pid) if (msg->pid == pid) { dbg("<== exec seq %d 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 void reap_kids() +{ + /* reap all dead children */ + while(1) { + int pid = waitpid(-1, 0, WNOHANG); + if ((pid == -1) || (pid == 0)) + break; + udev_done(pid); + } +} + +/* just read everything from the pipe and clear the flag, + * the useful flags were set in the signal handler + */ +static void user_sighandler() +{ + 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[]) { - int ssock; + int ssock, maxsockplus; struct sockaddr_un saddr; socklen_t addrlen; int retval; + const int on = 1; + struct sigaction act; + fd_set readfds; init_logging("udevd"); + dbg("version %s", UDEV_VERSION); - signal(SIGINT, sig_handler); - signal(SIGTERM, sig_handler); - signal(SIGALRM, sig_handler); - signal(SIGCHLD, sig_handler); + if (getuid() != 0) { + dbg("need to be root, exit"); + exit(1); + } + + /* 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[1], F_SETFL, O_NONBLOCK); + if (retval < 0) { + dbg("error fcntl on write pipe: %s", strerror(errno)); + exit(1); + } + + /* set signal handlers */ + act.sa_handler = 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; @@ -299,34 +444,70 @@ 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); } /* 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; } + /* enable receiving of the sender credentials */ + setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(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); - while(msg_q_timeout) { - msg_q_timeout = 0; - msg_queue_manager(); + if (retval < 0) { + if (errno != EINTR) + dbg("error in select: %s", strerror(errno)); + continue; } - while(children_waiting) { + if (FD_ISSET(ssock, &workreadfds)) + handle_msg(ssock); + + if (FD_ISSET(pipefds[0], &workreadfds)) + user_sighandler(); + + if (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); + reap_kids(); + } + + if (run_msg_q) { + run_msg_q = 0; + msg_queue_manager(); + } + + if (run_exec_q) { + /* this is tricky. exec_queue_manager() loops over exec_list, and + * calls running_with_devpath(), which loops over running_list. This gives + * O(N*M), which can get *nasty*. Clean up running_list before + * calling exec_queue_manager(). + */ + if (children_waiting) { + children_waiting = 0; + reap_kids(); } + + run_exec_q = 0; + exec_queue_manager(); } } exit: