From 04ebb5956719e3e301e1c08443c496ad97399544 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 11 Apr 2012 02:04:46 +0200 Subject: [PATCH] shutdownd: rework interface, allow subscribing to scheduled shutdowns This extends the shutdownd interface to expose schedule shutdown information in /run/systemd/shutdown/schedule. This also cleans up the shutdownd protocol and documents it in a header file sd-shutdown.h. This is supposed to be used by client code that wants to control and monitor scheduled shutdown. --- Makefile.am | 7 +- src/shutdownd.c | 230 ++++++++++++++++++++++++++++---------- src/shutdownd.h | 46 -------- src/systemctl.c | 48 ++++---- src/systemd/sd-shutdown.h | 108 ++++++++++++++++++ tmpfiles.d/systemd.conf | 1 + 6 files changed, 313 insertions(+), 127 deletions(-) delete mode 100644 src/shutdownd.h create mode 100644 src/systemd/sd-shutdown.h diff --git a/Makefile.am b/Makefile.am index 0aebeb2d..d2dfc9cf 100644 --- a/Makefile.am +++ b/Makefile.am @@ -761,7 +761,6 @@ libsystemd_core_la_SOURCES = \ src/bus-errors.h \ src/cgroup-show.h \ src/build.h \ - src/shutdownd.h \ src/umount.h \ src/ask-password-api.h \ src/sysfs-show.h \ @@ -934,9 +933,13 @@ systemd_shutdownd_SOURCES = \ src/shutdownd.c systemd_shutdownd_LDADD = \ - libsystemd-shared.la \ + libsystemd-shared-selinux.la \ libsystemd-daemon.la +pkginclude_HEADERS += \ + src/systemd/sd-shutdown.h + +# ------------------------------------------------------------------------------ systemd_shutdown_SOURCES = \ src/mount-setup.c \ src/umount.c \ diff --git a/src/shutdownd.c b/src/shutdownd.c index b4052d49..9801b5e1 100644 --- a/src/shutdownd.c +++ b/src/shutdownd.c @@ -28,16 +28,23 @@ #include #include #include +#include #include +#include -#include "shutdownd.h" #include "log.h" #include "macro.h" #include "util.h" #include "utmp-wtmp.h" +#include "mkdir.h" -static int read_packet(int fd, struct shutdownd_command *_c) { +union shutdown_buffer { + struct sd_shutdown_command command; + char space[offsetof(struct sd_shutdown_command, wall_message) + LINE_MAX]; +}; + +static int read_packet(int fd, union shutdown_buffer *_b) { struct msghdr msghdr; struct iovec iovec; struct ucred *ucred; @@ -45,15 +52,15 @@ static int read_packet(int fd, struct shutdownd_command *_c) { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; } control; - struct shutdownd_command c; ssize_t n; + union shutdown_buffer b; /* We maintain our own copy here, in order not to corrupt the last message */ assert(fd >= 0); - assert(_c); + assert(_b); zero(iovec); - iovec.iov_base = &c; - iovec.iov_len = sizeof(c); + iovec.iov_base = &b; + iovec.iov_len = sizeof(b) - 1; zero(control); zero(msghdr); @@ -62,8 +69,9 @@ static int read_packet(int fd, struct shutdownd_command *_c) { msghdr.msg_control = &control; msghdr.msg_controllen = sizeof(control); - if ((n = recvmsg(fd, &msghdr, MSG_DONTWAIT)) <= 0) { - if (n >= 0) { + n = recvmsg(fd, &msghdr, MSG_DONTWAIT); + if (n <= 0) { + if (n == 0) { log_error("Short read"); return -EIO; } @@ -89,18 +97,27 @@ static int read_packet(int fd, struct shutdownd_command *_c) { return 0; } - if (n != sizeof(c)) { - log_warning("Message has invalid size. Ignoring"); + if ((size_t) n < offsetof(struct sd_shutdown_command, wall_message)) { + log_warning("Message has invalid size. Ignoring."); + return 0; + } + + if (b.command.mode != SD_SHUTDOWN_NONE && + b.command.mode != SD_SHUTDOWN_REBOOT && + b.command.mode != SD_SHUTDOWN_POWEROFF && + b.command.mode != SD_SHUTDOWN_HALT && + b.command.mode != SD_SHUTDOWN_KEXEC) { + log_warning("Message has invalid mode. Ignoring."); return 0; } - char_array_0(c.wall_message); + b.space[n] = 0; - *_c = c; + *_b = b; return 1; } -static void warn_wall(usec_t n, struct shutdownd_command *c) { +static void warn_wall(usec_t n, struct sd_shutdown_command *c) { char date[FORMAT_TIMESTAMP_MAX]; const char *prefix; char *l = NULL; @@ -108,20 +125,22 @@ static void warn_wall(usec_t n, struct shutdownd_command *c) { assert(c); assert(c->warn_wall); - if (n >= c->elapse) + if (n >= c->usec) return; - if (c->mode == 'H') + if (c->mode == SD_SHUTDOWN_HALT) prefix = "The system is going down for system halt at "; - else if (c->mode == 'P') + else if (c->mode == SD_SHUTDOWN_POWEROFF) prefix = "The system is going down for power-off at "; - else if (c->mode == 'r') + else if (c->mode == SD_SHUTDOWN_REBOOT) prefix = "The system is going down for reboot at "; + else if (c->mode == SD_SHUTDOWN_KEXEC) + prefix = "The system is going down for kexec 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) + prefix, format_timestamp(date, sizeof(date), c->usec)) < 0) log_error("Failed to allocate wall message"); else { utmp_wall(l, NULL); @@ -164,6 +183,85 @@ static usec_t when_nologin(usec_t elapse) { return elapse > 5*USEC_PER_MINUTE ? elapse - 5*USEC_PER_MINUTE : 1; } +static const char *mode_to_string(enum sd_shutdown_mode m) { + switch (m) { + case SD_SHUTDOWN_REBOOT: + return "reboot"; + case SD_SHUTDOWN_POWEROFF: + return "poweroff"; + case SD_SHUTDOWN_HALT: + return "halt"; + case SD_SHUTDOWN_KEXEC: + return "kexec"; + default: + return NULL; + } +} + +static int update_schedule_file(struct sd_shutdown_command *c) { + int r; + FILE *f; + char *temp_path, *t; + + assert(c); + + r = safe_mkdir("/run/systemd/shutdown", 0755, 0, 0); + if (r < 0) { + log_error("Failed to create shutdown subdirectory: %s", strerror(-r)); + return r; + } + + t = cescape(c->wall_message); + if (!t) { + log_error("Out of memory"); + return -ENOMEM; + } + + r = fopen_temporary("/run/systemd/shutdown/scheduled", &f, &temp_path); + if (r < 0) { + log_error("Failed to save information about scheduled shutdowns: %s", strerror(-r)); + free(t); + return r; + } + + fchmod(fileno(f), 0644); + + fprintf(f, + "USEC=%llu\n" + "WARN_WALL=%i\n" + "MODE=%s\n", + (unsigned long long) c->usec, + c->warn_wall, + mode_to_string(c->mode)); + + if (c->dry_run) + fputs("DRY_RUN=1\n", f); + + if (!isempty(t)) + fprintf(f, "WALL_MESSAGE=%s\n", t); + + free(t); + + fflush(f); + + if (ferror(f) || rename(temp_path, "/run/systemd/shutdown/scheduled") < 0) { + log_error("Failed to write information about scheduled shutdowns: %m"); + r = -errno; + + unlink(temp_path); + unlink("/run/systemd/shutdown/scheduled"); + } + + fclose(f); + free(temp_path); + + return r; +} + +static bool scheduled(struct sd_shutdown_command *c) { + return c->usec > 0 && c->mode != SD_SHUTDOWN_NONE; +} + int main(int argc, char *argv[]) { enum { FD_SOCKET, @@ -174,9 +272,9 @@ int main(int argc, char *argv[]) { }; int r = EXIT_FAILURE, n_fds; - struct shutdownd_command c; + union shutdown_buffer b; struct pollfd pollfd[_FD_MAX]; - bool exec_shutdown = false, unlink_nologin = false, failed = false; + bool exec_shutdown = false, unlink_nologin = false; unsigned i; if (getppid() != 1) { @@ -195,7 +293,8 @@ int main(int argc, char *argv[]) { umask(0022); - if ((n_fds = sd_listen_fds(true)) < 0) { + n_fds = sd_listen_fds(true); + if (n_fds < 0) { log_error("Failed to read listening file descriptors from environment: %s", strerror(-r)); return EXIT_FAILURE; } @@ -205,39 +304,33 @@ int main(int argc, char *argv[]) { return EXIT_FAILURE; } - zero(c); + zero(b); 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; - + for (i = FD_WALL_TIMER; i < _FD_MAX; i++) { pollfd[i].events = POLLIN; - - if ((pollfd[i].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC)) < 0) { + pollfd[i].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC); + if (pollfd[i].fd < 0) { log_error("timerfd_create(): %m"); - failed = true; + goto finish; } } - 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 { + for (;;) { int k; usec_t n; - if (poll(pollfd, _FD_MAX, -1) < 0) { + k = poll(pollfd, _FD_MAX, scheduled(&b.command) ? -1 : 0); + if (k < 0) { if (errno == EAGAIN || errno == EINTR) continue; @@ -246,34 +339,44 @@ int main(int argc, char *argv[]) { goto finish; } + /* Exit on idle */ + if (k == 0) + break; + n = now(CLOCK_REALTIME); if (pollfd[FD_SOCKET].revents) { - if ((k = read_packet(pollfd[FD_SOCKET].fd, &c)) < 0) + k = read_packet(pollfd[FD_SOCKET].fd, &b); + if (k < 0) goto finish; - else if (k > 0 && c.elapse > 0) { + else if (k > 0) { struct itimerspec its; char date[FORMAT_TIMESTAMP_MAX]; - if (c.warn_wall) { + if (!scheduled(&b.command)) { + log_info("Shutdown canceled."); + break; + } + + zero(its); + if (b.command.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; - } + timespec_store(&its.it_value, when_wall(n, b.command.usec)); /* Warn immediately if less than 15 minutes are left */ - if (n < c.elapse && - n + 15*USEC_PER_MINUTE >= c.elapse) - warn_wall(n, &c); + if (n < b.command.usec && + n + 15*USEC_PER_MINUTE >= b.command.usec) + warn_wall(n, &b.command); + } + if (timerfd_settime(pollfd[FD_WALL_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { + log_error("timerfd_settime(): %m"); + goto finish; } /* Disallow logins 5 minutes prior to shutdown */ zero(its); - timespec_store(&its.it_value, when_nologin(c.elapse)); + timespec_store(&its.it_value, when_nologin(b.command.usec)); if (timerfd_settime(pollfd[FD_NOLOGIN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; @@ -281,27 +384,32 @@ int main(int argc, char *argv[]) { /* Shutdown after the specified time is reached */ zero(its); - timespec_store(&its.it_value, c.elapse); + timespec_store(&its.it_value, b.command.usec); if (timerfd_settime(pollfd[FD_SHUTDOWN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; } + update_schedule_file(&b.command); + sd_notifyf(false, - "STATUS=Shutting down at %s...", - format_timestamp(date, sizeof(date), c.elapse)); + "STATUS=Shutting down at %s (%s)...", + format_timestamp(date, sizeof(date), b.command.usec), + mode_to_string(b.command.mode)); + + log_info("Shutting down at %s (%s)...", date, mode_to_string(b.command.mode)); } } if (pollfd[FD_WALL_TIMER].revents) { struct itimerspec its; - warn_wall(n, &c); + warn_wall(n, &b.command); flush_fd(pollfd[FD_WALL_TIMER].fd); /* Restart timer */ zero(its); - timespec_store(&its.it_value, when_wall(n, c.elapse)); + timespec_store(&its.it_value, when_wall(n, b.command.usec)); if (timerfd_settime(pollfd[FD_WALL_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) { log_error("timerfd_settime(): %m"); goto finish; @@ -313,7 +421,8 @@ int main(int argc, char *argv[]) { log_info("Creating /run/nologin, blocking further logins..."); - if ((e = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0) + e = write_one_line_file_atomic("/run/nologin", "System is going down."); + if (e < 0) log_error("Failed to create /run/nologin: %s", strerror(-e)); else unlink_nologin = true; @@ -325,8 +434,7 @@ int main(int argc, char *argv[]) { exec_shutdown = true; goto finish; } - - } while (c.elapse > 0); + } r = EXIT_SUCCESS; @@ -341,19 +449,21 @@ finish: if (unlink_nologin) unlink("/run/nologin"); - if (exec_shutdown && !c.dry_run) { + unlink("/run/systemd/shutdown/scheduled"); + + if (exec_shutdown && !b.command.dry_run) { char sw[3]; sw[0] = '-'; - sw[1] = c.mode; + sw[1] = b.command.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"), + (b.command.warn_wall && b.command.wall_message[0]) ? b.command.wall_message : + (b.command.warn_wall ? NULL : "--no-wall"), NULL); log_error("Failed to execute /sbin/shutdown: %m"); diff --git a/src/shutdownd.h b/src/shutdownd.h deleted file mode 100644 index 45816497..00000000 --- a/src/shutdownd.h +++ /dev/null @@ -1,46 +0,0 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - -#ifndef fooshutdowndhfoo -#define fooshutdowndhfoo - -/*** - 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 . -***/ - -#include "util.h" -#include "macro.h" - -/* This is a private message, we don't care much about ABI - * stability. */ - -_packed_ struct shutdownd_command { - usec_t elapse; - char mode; /* H, P, r, i.e. the switches usually passed to - * shutdown to select whether to halt, power-off or - * reboot the machine */ - bool dry_run; - bool warn_wall; - - /* Yepp, sometimes we are lazy and use fixed-size strings like - * this one. Shame on us. But then again, we'd have to - * pre-allocate the receive buffer anyway, so there's nothing - * too bad here. */ - char wall_message[4096]; -}; - -#endif diff --git a/src/systemctl.c b/src/systemctl.c index 3cab0dd8..43a1446a 100644 --- a/src/systemctl.c +++ b/src/systemctl.c @@ -36,6 +36,7 @@ #include #include +#include #include "log.h" #include "util.h" @@ -51,7 +52,6 @@ #include "list.h" #include "path-lookup.h" #include "conf-parser.h" -#include "shutdownd.h" #include "exit-status.h" #include "bus-errors.h" #include "build.h" @@ -4628,6 +4628,7 @@ static int shutdown_parse_argv(int argc, char *argv[]) { { "halt", no_argument, NULL, 'H' }, { "poweroff", no_argument, NULL, 'P' }, { "reboot", no_argument, NULL, 'r' }, + { "kexec", no_argument, NULL, 'K' }, /* not documented extension */ { "no-wall", no_argument, NULL, ARG_NO_WALL }, { NULL, 0, NULL, 0 } }; @@ -4659,6 +4660,10 @@ static int shutdown_parse_argv(int argc, char *argv[]) { arg_action = ACTION_REBOOT; break; + case 'K': + arg_action = ACTION_KEXEC; + break; + case 'h': if (arg_action != ACTION_HALT) arg_action = ACTION_POWEROFF; @@ -5191,39 +5196,42 @@ static int systemctl_main(DBusConnection *bus, int argc, char *argv[], DBusError } static int send_shutdownd(usec_t t, char mode, bool dry_run, bool warn, const char *message) { - int fd = -1; + int fd; struct msghdr msghdr; - struct iovec iovec; + struct iovec iovec[2]; union sockaddr_union sockaddr; - struct shutdownd_command c; + struct sd_shutdown_command c; + + fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0); + if (fd < 0) + return -errno; zero(c); - c.elapse = t; + c.usec = t; c.mode = mode; c.dry_run = dry_run; c.warn_wall = warn; - if (message) - strncpy(c.wall_message, message, sizeof(c.wall_message)); - - if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) - return -errno; - zero(sockaddr); sockaddr.sa.sa_family = AF_UNIX; - sockaddr.un.sun_path[0] = 0; strncpy(sockaddr.un.sun_path, "/run/systemd/shutdownd", sizeof(sockaddr.un.sun_path)); - zero(iovec); - iovec.iov_base = (char*) &c; - iovec.iov_len = sizeof(c); - zero(msghdr); msghdr.msg_name = &sockaddr; msghdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) + sizeof("/run/systemd/shutdownd") - 1; - msghdr.msg_iov = &iovec; - msghdr.msg_iovlen = 1; + zero(iovec); + iovec[0].iov_base = (char*) &c; + iovec[0].iov_len = offsetof(struct sd_shutdown_command, wall_message); + + if (isempty(message)) + msghdr.msg_iovlen = 1; + else { + iovec[1].iov_base = (char*) message; + iovec[1].iov_len = strlen(message); + msghdr.msg_iovlen = 2; + } + msghdr.msg_iov = iovec; if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) < 0) { close_nointr_nofail(fd); @@ -5338,6 +5346,7 @@ static int halt_main(DBusConnection *bus) { r = send_shutdownd(arg_when, arg_action == ACTION_HALT ? 'H' : arg_action == ACTION_POWEROFF ? 'P' : + arg_action == ACTION_KEXEC ? 'K' : 'r', arg_dry, !arg_no_wall, @@ -5405,7 +5414,8 @@ int main(int argc, char*argv[]) { log_parse_environment(); log_open(); - if ((r = parse_argv(argc, argv)) < 0) + r = parse_argv(argc, argv); + if (r < 0) goto finish; else if (r == 0) { retval = EXIT_SUCCESS; diff --git a/src/systemd/sd-shutdown.h b/src/systemd/sd-shutdown.h new file mode 100644 index 00000000..29fcf341 --- /dev/null +++ b/src/systemd/sd-shutdown.h @@ -0,0 +1,108 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +#ifndef foosdshutdownhfoo +#define foosdshutdownhfoo + +/*** + 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 . +***/ + +/* Interface for scheduling and cancelling timed shutdowns. */ + +#include + +typedef enum sd_shutdown_mode { + SD_SHUTDOWN_NONE = 0, + SD_SHUTDOWN_REBOOT = 'r', + SD_SHUTDOWN_POWEROFF = 'P', + SD_SHUTDOWN_HALT = 'H', + SD_SHUTDOWN_KEXEC = 'K' +} sd_shutdown_mode_t; + +/* Calculate the size of the message as "offsetof(struct + * sd_shutdown_command, wall_message) + + * strlen(command.wall_message)" */ +__attribute__((packed)) struct sd_shutdown_command { + /* Microseconds after the epoch 1970 UTC */ + uint64_t usec; + + /* H, P, r, i.e. the switches usually passed to + * /usr/bin/shutdown to select whether to halt, power-off or + * reboot the machine */ + sd_shutdown_mode_t mode:8; + + /* If non-zero, don't actually shut down, just pretend */ + unsigned dry_run:1; + + /* If non-zero, send our wall message */ + unsigned warn_wall:1; + + /* The wall message to send around. Leave empty for the + * default wall message */ + char wall_message[]; +}; + +/* The scheme is very simple: + * + * To schedule a shutdown, simply fill in and send a single + * AF_UNIX/SOCK_DGRAM datagram with the structure above suffixed with + * the wall message to the socket /run/systemd/shutdownd (leave an + * empty wall message for the default shutdown message). To calculate + * the size of the message use "offsetof(struct sd_shutdown_command, + * wall_message) + strlen(command.wall_message)". + * + * To cancel a shutdown, do the same, but send an fully zeroed out + * structure. + * + * To be notified about scheduled shutdowns, create an inotify watch + * on /run/shutdown/. Whenever a file called "scheduled" appears a + * shutdown is scheduled. If it is removed it is canceled. It is + * replaced the scheduled shutdown has been changed. The file contains + * a simple environment-like block, that contains information about + * the scheduled shutdown: + * + * USEC= + * encodes the time for the shutdown in usecs since the epoch UTC, + * formatted as numeric string. + * + * WARN_WALL= + * is 1 if a wall message shall be sent + * + * DRY_RUN= + * is 1 if a dry run shutdown is scheduled + * + * MODE= + * is the shutdown mode, one of "poweroff", "reboot", "halt", "kexec" + * + * WALL_MESSAGE= + * is the wall message to use, with all special characters escape in C style. + * + * Note that some fields might be missing if they do not apply. + * + * Note that the file is first written to a temporary file and then + * renamed, in order to provide atomic properties for readers: if the + * file exists under the name "scheduled" it is guaranteed to be fully + * written. A reader should ignore all files in that directory by any + * other name. + * + * Scheduled shutdowns are only accepted from privileged processes, + * but the directory may be watched and the file in it read by + * anybody. + */ + +#endif diff --git a/tmpfiles.d/systemd.conf b/tmpfiles.d/systemd.conf index be29c068..2f9b0384 100644 --- a/tmpfiles.d/systemd.conf +++ b/tmpfiles.d/systemd.conf @@ -23,3 +23,4 @@ d /run/systemd/ask-password 0755 root root - d /run/systemd/seats 0755 root root - d /run/systemd/sessions 0755 root root - d /run/systemd/users 0755 root root - +d /run/systemd/shutdown 0755 root root - -- 2.39.5