/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2010 Lennart Poettering systemd 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. systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/socket.h> #include <sys/poll.h> #include <sys/types.h> #include <sys/timerfd.h> #include <assert.h> #include <string.h> #include <errno.h> #include <unistd.h> #include <fcntl.h> #include "shutdownd.h" #include "log.h" #include "macro.h" #include "util.h" #include "sd-daemon.h" #include "utmp-wtmp.h" static int read_packet(int fd, struct shutdownd_command *_c) { struct msghdr msghdr; struct iovec iovec; struct ucred *ucred; union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; } control; struct shutdownd_command c; ssize_t n; assert(fd >= 0); assert(_c); zero(iovec); iovec.iov_base = &c; iovec.iov_len = sizeof(c); zero(control); zero(msghdr); msghdr.msg_iov = &iovec; msghdr.msg_iovlen = 1; msghdr.msg_control = &control; msghdr.msg_controllen = sizeof(control); if ((n = recvmsg(fd, &msghdr, MSG_DONTWAIT)) <= 0) { if (n >= 0) { log_error("Short read"); return -EIO; } if (errno == EAGAIN || errno == EINTR) return 0; log_error("recvmsg(): %m"); return -errno; } if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) || control.cmsghdr.cmsg_level != SOL_SOCKET || control.cmsghdr.cmsg_type != SCM_CREDENTIALS || control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) { log_warning("Received message without credentials. Ignoring."); return 0; } ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr); if (ucred->uid != 0) { log_warning("Got request from unprivileged user. Ignoring."); return 0; } if (n != sizeof(c)) { log_warning("Message has invalid size. Ignoring"); return 0; } char_array_0(c.wall_message); *_c = c; return 1; } static void warn_wall(usec_t n, struct shutdownd_command *c) { char date[FORMAT_TIMESTAMP_MAX]; const char *prefix; char *l = NULL; assert(c); assert(c->warn_wall); if (n >= c->elapse) return; if (c->mode == 'H') prefix = "The system is going down for system halt at "; else if (c->mode == 'P') prefix = "The system is going down for power-off at "; else if (c->mode == 'r') prefix = "The system is going down for reboot at "; else assert_not_reached("Unknown mode!"); if (asprintf(&l, "%s%s%s%s!", c->wall_message, c->wall_message[0] ? "\n" : "", prefix, format_timestamp(date, sizeof(date), c->elapse)) < 0) log_error("Failed to allocate wall message"); else { utmp_wall(l, NULL); free(l); } } static usec_t when_wall(usec_t n, usec_t elapse) { static const struct { usec_t delay; usec_t interval; } table[] = { { 10 * USEC_PER_MINUTE, USEC_PER_MINUTE }, { USEC_PER_HOUR, 15 * USEC_PER_MINUTE }, { 3 * USEC_PER_HOUR, 30 * USEC_PER_MINUTE } }; usec_t left, sub; unsigned i; /* If the time is already passed, then don't announce */ if (n >= elapse) return 0; left = elapse - n; for (i = 0; i < ELEMENTSOF(table); i++) if (n + table[i].delay >= elapse) { sub = ((left / table[i].interval) * table[i].interval); break; } if (i >= ELEMENTSOF(table)) sub = ((left / USEC_PER_HOUR) * USEC_PER_HOUR); return elapse > sub ? elapse - sub : 1; } static usec_t when_nologin(usec_t elapse) { return elapse > 5*USEC_PER_MINUTE ? elapse - 5*USEC_PER_MINUTE : 1; } int main(int argc, char *argv[]) { enum { FD_SOCKET, FD_WALL_TIMER, FD_NOLOGIN_TIMER, FD_SHUTDOWN_TIMER, _FD_MAX }; int r = EXIT_FAILURE, n_fds; struct shutdownd_command c; struct pollfd pollfd[_FD_MAX]; bool exec_shutdown = false, unlink_nologin = false, failed = false; unsigned i; if (getppid() != 1) { log_error("This program should be invoked by init only."); return EXIT_FAILURE; } if (argc > 1) { log_error("This program does not take arguments."); return EXIT_FAILURE; } log_set_target(LOG_TARGET_SYSLOG_OR_KMSG); log_parse_environment(); log_open(); umask(0022); if ((n_fds = sd_listen_fds(true)) < 0) { log_error("Failed to read listening file descriptors from environment: %s", strerror(-r)); return EXIT_FAILURE; } if (n_fds != 1) { log_error("Need exactly one file descriptor."); return EXIT_FAILURE; } zero(c); zero(pollfd); pollfd[FD_SOCKET].fd = SD_LISTEN_FDS_START; pollfd[FD_SOCKET].events = POLLIN; for (i = 0; i < _FD_MAX; i++) { if (i == FD_SOCKET) continue; pollfd[i].events = POLLIN; if ((pollfd[i].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC)) < 0) { log_error("timerfd_create(): %m"); failed = true; } } if (failed) goto finish; log_debug("systemd-shutdownd running as pid %lu", (unsigned long) getpid()); sd_notify(false, "READY=1\n" "STATUS=Processing requests..."); do { int k; usec_t n; if (poll(pollfd, _FD_MAX, -1) < 0) { if (errno == EAGAIN || errno == EINTR) continue; log_error("poll(): %m"); goto finish; } n = now(CLOCK_REALTIME); if (pollfd[FD_SOCKET].revents) { if ((k = read_packet(pollfd[FD_SOCKET].fd, &c)) < 0) goto finish; else if (k > 0 && c.elapse > 0) { struct itimerspec its; char date[FORMAT_TIMESTAMP_MAX]; if (c.warn_wall) { /* Send wall messages every so often */ zero(its); timespec_store(&its.it_value, when_wall(n, c.elapse)); if (timerfd_settime(pollfd[FD_WALL_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; } /* Warn immediately if less than 15 minutes are left */ if (n < c.elapse && n + 15*USEC_PER_MINUTE >= c.elapse) warn_wall(n, &c); } /* Disallow logins 5 minutes prior to shutdown */ zero(its); timespec_store(&its.it_value, when_nologin(c.elapse)); if (timerfd_settime(pollfd[FD_NOLOGIN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; } /* Shutdown after the specified time is reached */ zero(its); timespec_store(&its.it_value, c.elapse); if (timerfd_settime(pollfd[FD_SHUTDOWN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; } sd_notifyf(false, "STATUS=Shutting down at %s...", format_timestamp(date, sizeof(date), c.elapse)); } } if (pollfd[FD_WALL_TIMER].revents) { struct itimerspec its; warn_wall(n, &c); flush_fd(pollfd[FD_WALL_TIMER].fd); /* Restart timer */ zero(its); timespec_store(&its.it_value, when_wall(n, c.elapse)); if (timerfd_settime(pollfd[FD_WALL_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; } } if (pollfd[FD_NOLOGIN_TIMER].revents) { int e; log_info("Creating /run/nologin, blocking further logins..."); if ((e = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0) log_error("Failed to create /run/nologin: %s", strerror(-e)); else unlink_nologin = true; flush_fd(pollfd[FD_NOLOGIN_TIMER].fd); } if (pollfd[FD_SHUTDOWN_TIMER].revents) { exec_shutdown = true; goto finish; } } while (c.elapse > 0); r = EXIT_SUCCESS; log_debug("systemd-shutdownd stopped as pid %lu", (unsigned long) getpid()); finish: for (i = 0; i < _FD_MAX; i++) if (pollfd[i].fd >= 0) close_nointr_nofail(pollfd[i].fd); if (unlink_nologin) unlink("/run/nologin"); if (exec_shutdown && !c.dry_run) { char sw[3]; sw[0] = '-'; sw[1] = c.mode; sw[2] = 0; execl(SYSTEMCTL_BINARY_PATH, "shutdown", sw, "now", (c.warn_wall && c.wall_message[0]) ? c.wall_message : (c.warn_wall ? NULL : "--no-wall"), NULL); log_error("Failed to execute /sbin/shutdown: %m"); } sd_notify(false, "STATUS=Exiting..."); return r; }