1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
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.
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.
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/>.
22 #include <sys/socket.h>
23 #include <sys/types.h>
31 #include <sys/epoll.h>
34 #include <sys/signalfd.h>
36 #include <systemd/sd-daemon.h>
42 #define SERVER_FD_MAX 16
44 typedef struct Stream Stream;
46 typedef struct Server {
53 static void server_done(Server *s) {
57 close_nointr_nofail(s->epoll_fd);
60 close_nointr_nofail(s->kmsg_fd);
62 if (s->signal_fd >= 0)
63 close_nointr_nofail(s->signal_fd);
66 fdset_free(s->syslog_fds);
69 static int server_init(Server *s) {
71 struct epoll_event ev;
77 s->kmsg_fd = s->signal_fd = -1;
79 s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
80 if (s->epoll_fd < 0) {
81 log_error("Failed to create epoll object: %m");
85 s->syslog_fds = fdset_new();
87 log_error("Failed to allocate file descriptor set: %s", strerror(ENOMEM));
91 n = sd_listen_fds(true);
93 log_error("Failed to read listening file descriptors from environment: %s", strerror(-n));
97 if (n <= 0 || n > SERVER_FD_MAX) {
98 log_error("No or too many file descriptors passed.");
102 for (i = 0; i < n; i++) {
105 fd = SD_LISTEN_FDS_START+i;
107 r = sd_is_socket(fd, AF_UNSPEC, SOCK_DGRAM, -1);
109 log_error("Failed to determine file descriptor type: %s", strerror(-r));
114 log_error("Wrong file descriptor type.");
121 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
122 log_error("Failed to add server fd to epoll object: %m");
126 r = fdset_put(s->syslog_fds, fd);
128 log_error("Failed to store file descriptor in set: %s", strerror(-r));
133 s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
134 if (s->kmsg_fd < 0) {
135 log_error("Failed to open /dev/kmsg for logging: %m");
139 assert_se(sigemptyset(&mask) == 0);
140 sigset_add_many(&mask, SIGINT, SIGTERM, -1);
141 assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
143 s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
144 if (s->signal_fd < 0) {
145 log_error("signalfd(): %m");
151 ev.data.fd = s->signal_fd;
153 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) {
154 log_error("epoll_ctl(): %m");
161 static int read_process(const char **buf, struct iovec *iovec) {
171 p += strspn(p, WHITESPACE);
172 l = strcspn(p, WHITESPACE);
197 iovec->iov_base = (char*) p;
203 static int write_message(Server *s, const char *buf, struct ucred *ucred) {
205 char priority[6], pid[16];
206 struct iovec iovec[5];
208 char *process = NULL;
210 int prio = LOG_USER | LOG_INFO;
215 parse_syslog_priority((char**) &buf, &prio);
220 if ((prio & LOG_FACMASK) == 0)
221 prio = LOG_USER | LOG_PRI(prio);
223 /* First, set priority field */
224 snprintf(priority, sizeof(priority), "<%i>", prio);
225 char_array_0(priority);
226 IOVEC_SET_STRING(iovec[i++], priority);
228 /* Second, skip date */
229 skip_syslog_date((char**) &buf);
231 /* Then, add process if set */
232 if (read_process(&buf, &iovec[i]) > 0)
236 get_process_comm(ucred->pid, &process) >= 0)
237 IOVEC_SET_STRING(iovec[i++], process);
239 /* Skip the stored PID if we have a better one */
241 snprintf(pid, sizeof(pid), "[%lu]: ", (unsigned long) ucred->pid);
243 IOVEC_SET_STRING(iovec[i++], pid);
245 skip_syslog_pid((char**) &buf);
250 buf += strspn(buf, WHITESPACE);
253 /* Is the remaining message empty? */
256 /* And the rest is the message */
257 IOVEC_SET_STRING(iovec[i++], buf);
258 IOVEC_SET_STRING(iovec[i++], "\n");
260 if ((k = writev(s->kmsg_fd, iovec, i)) <= 0) {
261 log_error("Failed to write log message to kmsg: %s", k < 0 ? strerror(errno) : "short write");
262 r = k < 0 ? -errno : -EIO;
271 static int process_event(Server *s, struct epoll_event *ev) {
274 if (ev->events != EPOLLIN) {
275 log_info("Got invalid event from epoll.");
279 if (ev->data.fd == s->signal_fd) {
280 struct signalfd_siginfo sfsi;
283 n = read(s->signal_fd, &sfsi, sizeof(sfsi));
284 if (n != sizeof(sfsi)) {
289 if (errno == EINTR || errno == EAGAIN)
295 log_debug("Received SIG%s", signal_to_string(sfsi.ssi_signo));
300 char buf[LINE_MAX+1];
301 struct msghdr msghdr;
305 struct cmsghdr cmsghdr;
306 uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
313 iovec.iov_base = buf;
314 iovec.iov_len = sizeof(buf)-1;
318 msghdr.msg_iov = &iovec;
319 msghdr.msg_iovlen = 1;
320 msghdr.msg_control = &control;
321 msghdr.msg_controllen = sizeof(control);
323 n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT);
326 if (errno == EINTR || errno == EAGAIN)
329 log_error("recvmsg() failed: %m");
333 if (msghdr.msg_controllen >= CMSG_LEN(sizeof(struct ucred)) &&
334 control.cmsghdr.cmsg_level == SOL_SOCKET &&
335 control.cmsghdr.cmsg_type == SCM_CREDENTIALS &&
336 control.cmsghdr.cmsg_len == CMSG_LEN(sizeof(struct ucred)))
337 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
341 e = memchr(buf, '\n', n);
347 k = write_message(s, strstrip(buf), ucred);
356 int main(int argc, char *argv[]) {
360 if (getppid() != 1) {
361 log_error("This program should be invoked by init only.");
366 log_error("This program does not take arguments.");
370 log_set_target(LOG_TARGET_KMSG);
371 log_parse_environment();
376 r = server_init(&server);
380 log_debug("systemd-kmsg-syslogd running as pid %lu", (unsigned long) getpid());
384 "STATUS=Processing messages...");
387 struct epoll_event event;
389 r = epoll_wait(server.epoll_fd, &event, 1, -1);
395 log_error("epoll_wait() failed: %m");
401 r = process_event(&server, &event);
408 log_debug("systemd-kmsg-syslogd stopped as pid %lu", (unsigned long) getpid());
412 "STATUS=Shutting down...");
414 server_done(&server);
416 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;