systemctl: add support for delayed shutdown, similar to sysv in style

1 files changed, 272 insertions, 0 deletions

diff --git a/src/shutdownd.c b/src/shutdownd.c
new file mode 100644
index 0000000000..241c4327a6
--- /dev/null
+++ b/src/shutdownd.c
@@ -0,0 +1,272 @@
+/*-*- 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 invaliud 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;
+}