[thirdparty/systemd.git] / src / shutdownd.c

/*-*- 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"

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;
        }

        *_c = c;
        return 1;
}

int main(int argc, char *argv[]) {
        enum {
                FD_SOCKET,
                FD_SHUTDOWN_TIMER,
                FD_NOLOGIN_TIMER,
                _FD_MAX
        };

        int r = 4, n;
        int one = 1;
        unsigned n_fds = 1;
        struct shutdownd_command c;
        struct pollfd pollfd[_FD_MAX];
        bool exec_shutdown = false, unlink_nologin = false;

        if (getppid() != 1) {
                log_error("This program should be invoked by init only.");
                return 1;
        }

        if (argc > 1) {
                log_error("This program does not take arguments.");
                return 1;
        }

        log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
        log_parse_environment();

        if ((n = sd_listen_fds(true)) < 0) {
                log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));
                return 1;
        }

        if (n != 1) {
                log_error("Need exactly one file descriptor.");
                return 2;
        }

        if (setsockopt(SD_LISTEN_FDS_START, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) {
                log_error("SO_PASSCRED failed: %m");
                return 3;
        }

        zero(c);
        zero(pollfd);

        pollfd[FD_SOCKET].fd = SD_LISTEN_FDS_START;
        pollfd[FD_SOCKET].events = POLLIN;
        pollfd[FD_SHUTDOWN_TIMER].fd = -1;
        pollfd[FD_SHUTDOWN_TIMER].events = POLLIN;
        pollfd[FD_NOLOGIN_TIMER].fd = -1;
        pollfd[FD_NOLOGIN_TIMER].events = POLLIN;

        log_debug("systemd-shutdownd running as pid %lu", (unsigned long) getpid());

        sd_notify(false,
                  "READY=1\n"
                  "STATUS=Processing requests...");

        do {
                int k;

                if (poll(pollfd, n_fds, -1) < 0) {

                        if (errno == EAGAIN || errno == EINTR)
                                continue;

                        log_error("poll(): %m");
                        goto finish;
                }

                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 buf[27];

                                if (pollfd[FD_SHUTDOWN_TIMER].fd < 0)
                                        if ((pollfd[FD_SHUTDOWN_TIMER].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC)) < 0) {
                                                log_error("timerfd_create(): %m");
                                                goto finish;
                                        }

                                if (pollfd[FD_NOLOGIN_TIMER].fd < 0)
                                        if ((pollfd[FD_NOLOGIN_TIMER].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC)) < 0) {
                                                log_error("timerfd_create(): %m");
                                                goto finish;
                                        }

                                /* Disallow logins 5 minutes prior to shutdown */
                                zero(its);
                                timespec_store(&its.it_value, c.elapse > 5*USEC_PER_MINUTE ? c.elapse - 5*USEC_PER_MINUTE : 0);
                                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;
                                }

                                n_fds = 3;

                                ctime_r(&its.it_value.tv_sec, buf);

                                sd_notifyf(false,
                                           "STATUS=Shutting down at %s...",
                                           strstrip(buf));
                        }
                }

                if (pollfd[FD_NOLOGIN_TIMER].fd >= 0 &&
                    pollfd[FD_NOLOGIN_TIMER].revents) {
                        int e;

                        if ((e = touch("/etc/nologin")) < 0)
                                log_error("Failed to create /etc/nologin: %s", strerror(-e));
                        else
                                unlink_nologin = true;

                        /* Disarm nologin timer */
                        close_nointr_nofail(pollfd[FD_NOLOGIN_TIMER].fd);
                        pollfd[FD_NOLOGIN_TIMER].fd = -1;
                        n_fds = 2;

                }

                if (pollfd[FD_SHUTDOWN_TIMER].fd >= 0 &&
                    pollfd[FD_SHUTDOWN_TIMER].revents) {
                        exec_shutdown = true;
                        goto finish;
                }

        } while (c.elapse > 0);

        r = 0;

        log_debug("systemd-shutdownd stopped as pid %lu", (unsigned long) getpid());

finish:
        if (pollfd[FD_SOCKET].fd >= 0)
                close_nointr_nofail(pollfd[FD_SOCKET].fd);

        if (pollfd[FD_SHUTDOWN_TIMER].fd >= 0)
                close_nointr_nofail(pollfd[FD_SHUTDOWN_TIMER].fd);

        if (pollfd[FD_NOLOGIN_TIMER].fd >= 0)
                close_nointr_nofail(pollfd[FD_NOLOGIN_TIMER].fd);

        if (exec_shutdown) {
                char sw[3];

                sw[0] = '-';
                sw[1] = c.mode;
                sw[2] = 0;

                execl(SYSTEMCTL_BINARY_PATH, "shutdown", sw, "now", NULL);
                log_error("Failed to execute /sbin/shutdown: %m");
        }

        if (unlink_nologin)
                unlink("/etc/nologin");

        sd_notify(false,
                  "STATUS=Exiting...");

        return r;
}
Commit	Line	Data
f6144808 LP	1	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/
	2
	3	/***
	4	This file is part of systemd.
	5
	6	Copyright 2010 Lennart Poettering
	7
	8	systemd is free software; you can redistribute it and/or modify it
	9	under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 2 of the License, or
	11	(at your option) any later version.
	12
	13	systemd is distributed in the hope that it will be useful, but
	14	WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	20	***/
	21
	22	#include <sys/socket.h>
	23	#include <sys/poll.h>
	24	#include <sys/types.h>
	25	#include <sys/timerfd.h>
	26	#include <assert.h>
	27	#include <string.h>
	28	#include <errno.h>
	29	#include <unistd.h>
	30	#include <fcntl.h>
	31
	32	#include "shutdownd.h"
	33	#include "log.h"
	34	#include "macro.h"
	35	#include "util.h"
	36	#include "sd-daemon.h"
	37
	38	static int read_packet(int fd, struct shutdownd_command *_c) {
	39	struct msghdr msghdr;
	40	struct iovec iovec;
	41	struct ucred *ucred;
	42	union {
	43	struct cmsghdr cmsghdr;
	44	uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
	45	} control;
	46	struct shutdownd_command c;
	47	ssize_t n;
	48
	49	assert(fd >= 0);
	50	assert(_c);
	51
	52	zero(iovec);
	53	iovec.iov_base = &c;
	54	iovec.iov_len = sizeof(c);
	55
	56	zero(control);
	57	zero(msghdr);
	58	msghdr.msg_iov = &iovec;
	59	msghdr.msg_iovlen = 1;
	60	msghdr.msg_control = &control;
	61	msghdr.msg_controllen = sizeof(control);
	62
	63	if ((n = recvmsg(fd, &msghdr, MSG_DONTWAIT)) <= 0) {
	64	if (n >= 0) {
65	log_error("Short read");
66	return -EIO;
67	}
68
69	if (errno == EAGAIN \|\| errno == EINTR)
70	return 0;
71
72	log_error("recvmsg(): %m");
73	return -errno;
74	}
75
76	if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) \|\|
77	control.cmsghdr.cmsg_level != SOL_SOCKET \|\|
78	control.cmsghdr.cmsg_type != SCM_CREDENTIALS \|\|
79	control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
80	log_warning("Received message without credentials. Ignoring.");
81	return 0;
82	}
83
84	ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
85	if (ucred->uid != 0) {
86	log_warning("Got request from unprivileged user. Ignoring.");
87	return 0;
88	}
89
90	if (n != sizeof(c)) {
6b5ad000	91	log_warning("Message has invalid size. Ignoring");
f6144808 LP	92	return 0;
	93	}
	94
	95	*_c = c;
	96	return 1;
	97	}
	98
	99	int main(int argc, char *argv[]) {
	100	enum {
	101	FD_SOCKET,
	102	FD_SHUTDOWN_TIMER,
	103	FD_NOLOGIN_TIMER,
	104	_FD_MAX
	105	};
	106
	107	int r = 4, n;
	108	int one = 1;
	109	unsigned n_fds = 1;
	110	struct shutdownd_command c;
	111	struct pollfd pollfd[_FD_MAX];
	112	bool exec_shutdown = false, unlink_nologin = false;
	113
	114	if (getppid() != 1) {
	115	log_error("This program should be invoked by init only.");
	116	return 1;
	117	}
	118
	119	if (argc > 1) {
	120	log_error("This program does not take arguments.");
	121	return 1;
	122	}
	123
	124	log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
	125	log_parse_environment();
	126
	127	if ((n = sd_listen_fds(true)) < 0) {
	128	log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));
	129	return 1;
	130	}
	131
	132	if (n != 1) {
	133	log_error("Need exactly one file descriptor.");
	134	return 2;
	135	}
	136
	137	if (setsockopt(SD_LISTEN_FDS_START, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) {
	138	log_error("SO_PASSCRED failed: %m");
	139	return 3;
	140	}
	141
	142	zero(c);
	143	zero(pollfd);
	144
	145	pollfd[FD_SOCKET].fd = SD_LISTEN_FDS_START;
	146	pollfd[FD_SOCKET].events = POLLIN;
	147	pollfd[FD_SHUTDOWN_TIMER].fd = -1;
	148	pollfd[FD_SHUTDOWN_TIMER].events = POLLIN;
	149	pollfd[FD_NOLOGIN_TIMER].fd = -1;
	150	pollfd[FD_NOLOGIN_TIMER].events = POLLIN;
	151
	152	log_debug("systemd-shutdownd running as pid %lu", (unsigned long) getpid());
	153
	154	sd_notify(false,
	155	"READY=1\n"
156	"STATUS=Processing requests...");
157
158	do {
159	int k;
160
161	if (poll(pollfd, n_fds, -1) < 0) {
162
163	if (errno == EAGAIN \|\| errno == EINTR)
164	continue;
165
166	log_error("poll(): %m");
167	goto finish;
168	}
169
170	if (pollfd[FD_SOCKET].revents) {
171
172	if ((k = read_packet(pollfd[FD_SOCKET].fd, &c)) < 0)
173	goto finish;
174	else if (k > 0 && c.elapse > 0) {
175	struct itimerspec its;
176	char buf[27];
177
178	if (pollfd[FD_SHUTDOWN_TIMER].fd < 0)
179	if ((pollfd[FD_SHUTDOWN_TIMER].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK\|TFD_CLOEXEC)) < 0) {
180	log_error("timerfd_create(): %m");
181	goto finish;
182	}
183
184	if (pollfd[FD_NOLOGIN_TIMER].fd < 0)
185	if ((pollfd[FD_NOLOGIN_TIMER].fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK\|TFD_CLOEXEC)) < 0) {
186	log_error("timerfd_create(): %m");
187	goto finish;
188	}
189
190	/* Disallow logins 5 minutes prior to shutdown */
191	zero(its);
192	timespec_store(&its.it_value, c.elapse > 5USEC_PER_MINUTE ? c.elapse - 5USEC_PER_MINUTE : 0);
193	if (timerfd_settime(pollfd[FD_NOLOGIN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) {
194	log_error("timerfd_settime(): %m");
195	goto finish;
196	}
197
198	/* Shutdown after the specified time is reached */
199	zero(its);
200	timespec_store(&its.it_value, c.elapse);
201	if (timerfd_settime(pollfd[FD_SHUTDOWN_TIMER].fd, TFD_TIMER_ABSTIME, &its, NULL) < 0) {
202	log_error("timerfd_settime(): %m");
203	goto finish;
204	}
205
206	n_fds = 3;
207
208	ctime_r(&its.it_value.tv_sec, buf);
209
210	sd_notifyf(false,
211	"STATUS=Shutting down at %s...",
212	strstrip(buf));
213	}
214	}
215
216	if (pollfd[FD_NOLOGIN_TIMER].fd >= 0 &&
217	pollfd[FD_NOLOGIN_TIMER].revents) {
218	int e;
219
220	if ((e = touch("/etc/nologin")) < 0)
221	log_error("Failed to create /etc/nologin: %s", strerror(-e));
222	else
223	unlink_nologin = true;
224
225	/* Disarm nologin timer */
226	close_nointr_nofail(pollfd[FD_NOLOGIN_TIMER].fd);
227	pollfd[FD_NOLOGIN_TIMER].fd = -1;
228	n_fds = 2;
229
230	}
231
232	if (pollfd[FD_SHUTDOWN_TIMER].fd >= 0 &&
233	pollfd[FD_SHUTDOWN_TIMER].revents) {
234	exec_shutdown = true;
235	goto finish;
236	}
237
238	} while (c.elapse > 0);
239
240	r = 0;
241
242	log_debug("systemd-shutdownd stopped as pid %lu", (unsigned long) getpid());
243
244	finish:
245	if (pollfd[FD_SOCKET].fd >= 0)
246	close_nointr_nofail(pollfd[FD_SOCKET].fd);
247
248	if (pollfd[FD_SHUTDOWN_TIMER].fd >= 0)
249	close_nointr_nofail(pollfd[FD_SHUTDOWN_TIMER].fd);
250
251	if (pollfd[FD_NOLOGIN_TIMER].fd >= 0)
252	close_nointr_nofail(pollfd[FD_NOLOGIN_TIMER].fd);
253
254	if (exec_shutdown) {
255	char sw[3];
256
257	sw[0] = '-';
258	sw[1] = c.mode;
259	sw[2] = 0;
260
261	execl(SYSTEMCTL_BINARY_PATH, "shutdown", sw, "now", NULL);
262	log_error("Failed to execute /sbin/shutdown: %m");
263	}
264
265	if (unlink_nologin)
266	unlink("/etc/nologin");
267
268	sd_notify(false,
269	"STATUS=Exiting...");
270
271	return r;
272	}