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>
38 #include "sd-daemon.h"
41 #define SERVER_FD_MAX 16
43 typedef struct Stream Stream;
45 typedef struct Server {
52 static void server_done(Server *s) {
56 close_nointr_nofail(s->epoll_fd);
59 close_nointr_nofail(s->kmsg_fd);
61 if (s->signal_fd >= 0)
62 close_nointr_nofail(s->signal_fd);
65 fdset_free(s->syslog_fds);
68 static int server_init(Server *s) {
70 struct epoll_event ev;
76 s->kmsg_fd = s->signal_fd = -1;
78 s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
79 if (s->epoll_fd < 0) {
80 log_error("Failed to create epoll object: %m");
84 s->syslog_fds = fdset_new();
86 log_error("Failed to allocate file descriptor set: %s", strerror(ENOMEM));
90 n = sd_listen_fds(true);
92 log_error("Failed to read listening file descriptors from environment: %s", strerror(-n));
96 if (n <= 0 || n > SERVER_FD_MAX) {
97 log_error("No or too many file descriptors passed.");
101 for (i = 0; i < n; i++) {
104 fd = SD_LISTEN_FDS_START+i;
106 r = sd_is_socket(fd, AF_UNSPEC, SOCK_DGRAM, -1);
108 log_error("Failed to determine file descriptor type: %s", strerror(-r));
113 log_error("Wrong file descriptor type.");
120 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
121 log_error("Failed to add server fd to epoll object: %m");
125 r = fdset_put(s->syslog_fds, fd);
127 log_error("Failed to store file descriptor in set: %s", strerror(-r));
132 s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
133 if (s->kmsg_fd < 0) {
134 log_error("Failed to open /dev/kmsg for logging: %m");
138 assert_se(sigemptyset(&mask) == 0);
139 sigset_add_many(&mask, SIGINT, SIGTERM, -1);
140 assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
142 s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
143 if (s->signal_fd < 0) {
144 log_error("signalfd(): %m");
150 ev.data.fd = s->signal_fd;
152 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) {
153 log_error("epoll_ctl(): %m");
160 static int read_process(const char **buf, struct iovec *iovec) {
170 p += strspn(p, WHITESPACE);
171 l = strcspn(p, WHITESPACE);
196 iovec->iov_base = (char*) p;
202 static int write_message(Server *s, const char *buf, struct ucred *ucred) {
204 char priority[6], pid[16];
205 struct iovec iovec[5];
207 char *process = NULL;
209 int prio = LOG_USER | LOG_INFO;
214 parse_syslog_priority((char**) &buf, &prio);
219 if ((prio & LOG_FACMASK) == 0)
220 prio = LOG_USER | LOG_PRI(prio);
222 /* First, set priority field */
223 snprintf(priority, sizeof(priority), "<%i>", prio);
224 char_array_0(priority);
225 IOVEC_SET_STRING(iovec[i++], priority);
227 /* Second, skip date */
228 skip_syslog_date((char**) &buf);
230 /* Then, add process if set */
231 if (read_process(&buf, &iovec[i]) > 0)
235 get_process_comm(ucred->pid, &process) >= 0)
236 IOVEC_SET_STRING(iovec[i++], process);
238 /* Skip the stored PID if we have a better one */
240 snprintf(pid, sizeof(pid), "[%lu]: ", (unsigned long) ucred->pid);
242 IOVEC_SET_STRING(iovec[i++], pid);
244 skip_syslog_pid((char**) &buf);
249 buf += strspn(buf, WHITESPACE);
252 /* Is the remaining message empty? */
255 /* And the rest is the message */
256 IOVEC_SET_STRING(iovec[i++], buf);
257 IOVEC_SET_STRING(iovec[i++], "\n");
259 if ((k = writev(s->kmsg_fd, iovec, i)) <= 0) {
260 log_error("Failed to write log message to kmsg: %s", k < 0 ? strerror(errno) : "short write");
261 r = k < 0 ? -errno : -EIO;
270 static int process_event(Server *s, struct epoll_event *ev) {
273 if (ev->events != EPOLLIN) {
274 log_info("Got invalid event from epoll.");
278 if (ev->data.fd == s->signal_fd) {
279 struct signalfd_siginfo sfsi;
282 n = read(s->signal_fd, &sfsi, sizeof(sfsi));
283 if (n != sizeof(sfsi)) {
288 if (errno == EINTR || errno == EAGAIN)
294 log_debug("Received SIG%s", signal_to_string(sfsi.ssi_signo));
299 char buf[LINE_MAX+1];
300 struct msghdr msghdr;
304 struct cmsghdr cmsghdr;
305 uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
312 iovec.iov_base = buf;
313 iovec.iov_len = sizeof(buf)-1;
317 msghdr.msg_iov = &iovec;
318 msghdr.msg_iovlen = 1;
319 msghdr.msg_control = &control;
320 msghdr.msg_controllen = sizeof(control);
322 n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT);
325 if (errno == EINTR || errno == EAGAIN)
328 log_error("recvmsg() failed: %m");
332 if (msghdr.msg_controllen >= CMSG_LEN(sizeof(struct ucred)) &&
333 control.cmsghdr.cmsg_level == SOL_SOCKET &&
334 control.cmsghdr.cmsg_type == SCM_CREDENTIALS &&
335 control.cmsghdr.cmsg_len == CMSG_LEN(sizeof(struct ucred)))
336 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
340 e = memchr(buf, '\n', n);
346 k = write_message(s, strstrip(buf), ucred);
355 int main(int argc, char *argv[]) {
359 if (getppid() != 1) {
360 log_error("This program should be invoked by init only.");
365 log_error("This program does not take arguments.");
369 log_set_target(LOG_TARGET_KMSG);
370 log_parse_environment();
375 r = server_init(&server);
379 log_debug("systemd-kmsg-syslogd running as pid %lu", (unsigned long) getpid());
383 "STATUS=Processing messages...");
386 struct epoll_event event;
388 r = epoll_wait(server.epoll_fd, &event, 1, -1);
394 log_error("epoll_wait() failed: %m");
400 r = process_event(&server, &event);
407 log_debug("systemd-kmsg-syslogd stopped as pid %lu", (unsigned long) getpid());
411 "STATUS=Shutting down...");
413 server_done(&server);
415 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;