420 lines
12 KiB
C
420 lines
12 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <time.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/poll.h>
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#include <sys/epoll.h>
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#include <sys/un.h>
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#include <fcntl.h>
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#include <sys/signalfd.h>
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#include "util.h"
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#include "log.h"
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#include "sd-daemon.h"
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#include "fdset.h"
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#define SERVER_FD_MAX 16
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typedef struct Stream Stream;
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typedef struct Server {
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FDSet *syslog_fds;
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int kmsg_fd;
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int epoll_fd;
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int signal_fd;
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} Server;
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static void server_done(Server *s) {
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assert(s);
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if (s->epoll_fd >= 0)
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close_nointr_nofail(s->epoll_fd);
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if (s->kmsg_fd >= 0)
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close_nointr_nofail(s->kmsg_fd);
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if (s->signal_fd >= 0)
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close_nointr_nofail(s->signal_fd);
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if (s->syslog_fds)
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fdset_free(s->syslog_fds);
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}
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static int server_init(Server *s) {
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int i, r, n;
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struct epoll_event ev;
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sigset_t mask;
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assert(s);
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zero(*s);
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s->kmsg_fd = s->signal_fd = -1;
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s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
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if (s->epoll_fd < 0) {
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log_error("Failed to create epoll object: %m");
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return -errno;
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}
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s->syslog_fds = fdset_new();
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if (!s->syslog_fds) {
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log_error("Failed to allocate file descriptor set: %s", strerror(ENOMEM));
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return -ENOMEM;
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}
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n = sd_listen_fds(true);
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if (n < 0) {
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log_error("Failed to read listening file descriptors from environment: %s", strerror(-n));
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return n;
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}
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if (n <= 0 || n > SERVER_FD_MAX) {
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log_error("No or too many file descriptors passed.");
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return -EINVAL;
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}
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for (i = 0; i < n; i++) {
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int fd, one = 1;
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fd = SD_LISTEN_FDS_START+i;
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r = sd_is_socket(fd, AF_UNSPEC, SOCK_DGRAM, -1);
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if (r < 0) {
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log_error("Failed to determine file descriptor type: %s", strerror(-r));
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return r;
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}
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if (!r) {
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log_error("Wrong file descriptor type.");
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return -EINVAL;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0)
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log_error("SO_PASSCRED failed: %m");
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zero(ev);
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ev.events = EPOLLIN;
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ev.data.fd = fd;
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if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
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log_error("Failed to add server fd to epoll object: %m");
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return -errno;
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}
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r = fdset_put(s->syslog_fds, fd);
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if (r < 0) {
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log_error("Failed to store file descriptor in set: %s", strerror(-r));
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return r;
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}
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}
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s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
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if (s->kmsg_fd < 0) {
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log_error("Failed to open /dev/kmsg for logging: %m");
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return -errno;
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}
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assert_se(sigemptyset(&mask) == 0);
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sigset_add_many(&mask, SIGINT, SIGTERM, -1);
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assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
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s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
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if (s->signal_fd < 0) {
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log_error("signalfd(): %m");
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return -errno;
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}
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zero(ev);
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ev.events = EPOLLIN;
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ev.data.fd = s->signal_fd;
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if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) {
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log_error("epoll_ctl(): %m");
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return -errno;
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}
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return 0;
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}
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static int read_process(const char **buf, struct iovec *iovec) {
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const char *p;
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size_t l;
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assert(buf);
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assert(*buf);
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assert(iovec);
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p = *buf;
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p += strspn(p, WHITESPACE);
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l = strcspn(p, WHITESPACE);
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if (l <= 0 ||
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p[l-1] != ':')
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return 0;
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l--;
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if (p[l-1] == ']') {
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size_t k = l-1;
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for (;;) {
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if (p[k] == '[') {
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l = k;
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break;
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}
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if (k == 0)
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break;
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k--;
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}
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}
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iovec->iov_base = (char*) p;
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iovec->iov_len = l;
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*buf = p + l;
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return 1;
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}
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static int write_message(Server *s, const char *buf, struct ucred *ucred) {
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ssize_t k;
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char priority[6], pid[16];
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struct iovec iovec[5];
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unsigned i = 0;
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char *process = NULL;
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int r = 0;
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int prio = LOG_USER | LOG_INFO;
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assert(s);
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assert(buf);
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parse_syslog_priority((char**) &buf, &prio);
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if (*buf == 0)
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return 0;
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if ((prio & LOG_FACMASK) == 0)
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prio = LOG_USER | LOG_PRI(prio);
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/* First, set priority field */
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snprintf(priority, sizeof(priority), "<%i>", prio);
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char_array_0(priority);
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IOVEC_SET_STRING(iovec[i++], priority);
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/* Second, skip date */
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skip_syslog_date((char**) &buf);
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/* Then, add process if set */
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if (read_process(&buf, &iovec[i]) > 0)
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i++;
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else if (ucred &&
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ucred->pid > 0 &&
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get_process_comm(ucred->pid, &process) >= 0)
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IOVEC_SET_STRING(iovec[i++], process);
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/* Skip the stored PID if we have a better one */
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if (ucred) {
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snprintf(pid, sizeof(pid), "[%lu]: ", (unsigned long) ucred->pid);
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char_array_0(pid);
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IOVEC_SET_STRING(iovec[i++], pid);
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skip_syslog_pid((char**) &buf);
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if (*buf == ':')
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buf++;
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buf += strspn(buf, WHITESPACE);
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}
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/* Is the remaining message empty? */
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if (*buf) {
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/* And the rest is the message */
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IOVEC_SET_STRING(iovec[i++], buf);
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IOVEC_SET_STRING(iovec[i++], "\n");
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if ((k = writev(s->kmsg_fd, iovec, i)) <= 0) {
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log_error("Failed to write log message to kmsg: %s", k < 0 ? strerror(errno) : "short write");
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r = k < 0 ? -errno : -EIO;
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}
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}
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free(process);
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return r;
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}
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static int process_event(Server *s, struct epoll_event *ev) {
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assert(s);
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if (ev->events != EPOLLIN) {
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log_info("Got invalid event from epoll.");
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return -EIO;
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}
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if (ev->data.fd == s->signal_fd) {
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struct signalfd_siginfo sfsi;
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ssize_t n;
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n = read(s->signal_fd, &sfsi, sizeof(sfsi));
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if (n != sizeof(sfsi)) {
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if (n >= 0)
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return -EIO;
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if (errno == EINTR || errno == EAGAIN)
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return 0;
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return -errno;
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}
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log_debug("Received SIG%s", signal_to_string(sfsi.ssi_signo));
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return 0;
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} else {
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for (;;) {
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char buf[LINE_MAX+1];
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struct msghdr msghdr;
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struct iovec iovec;
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struct ucred *ucred;
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union {
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struct cmsghdr cmsghdr;
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uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
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} control;
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ssize_t n;
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int k;
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char *e;
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zero(iovec);
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iovec.iov_base = buf;
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iovec.iov_len = sizeof(buf)-1;
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zero(control);
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zero(msghdr);
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msghdr.msg_iov = &iovec;
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msghdr.msg_iovlen = 1;
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msghdr.msg_control = &control;
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msghdr.msg_controllen = sizeof(control);
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n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT);
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if (n < 0) {
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if (errno == EINTR || errno == EAGAIN)
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return 1;
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log_error("recvmsg() failed: %m");
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return -errno;
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}
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if (msghdr.msg_controllen >= CMSG_LEN(sizeof(struct ucred)) &&
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control.cmsghdr.cmsg_level == SOL_SOCKET &&
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control.cmsghdr.cmsg_type == SCM_CREDENTIALS &&
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control.cmsghdr.cmsg_len == CMSG_LEN(sizeof(struct ucred)))
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ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
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else
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ucred = NULL;
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e = memchr(buf, '\n', n);
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if (e)
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*e = 0;
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else
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buf[n] = 0;
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k = write_message(s, strstrip(buf), ucred);
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if (k < 0)
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return k;
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}
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}
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return 1;
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}
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int main(int argc, char *argv[]) {
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Server server;
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int r;
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if (getppid() != 1) {
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log_error("This program should be invoked by init only.");
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return EXIT_FAILURE;
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}
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if (argc > 1) {
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log_error("This program does not take arguments.");
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return EXIT_FAILURE;
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}
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log_set_target(LOG_TARGET_KMSG);
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log_parse_environment();
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log_open();
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umask(0022);
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r = server_init(&server);
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if (r < 0)
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goto finish;
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log_debug("systemd-kmsg-syslogd running as pid %lu", (unsigned long) getpid());
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sd_notify(false,
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"READY=1\n"
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"STATUS=Processing messages...");
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for (;;) {
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struct epoll_event event;
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r = epoll_wait(server.epoll_fd, &event, 1, -1);
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if (r < 0) {
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if (errno == EINTR)
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continue;
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log_error("epoll_wait() failed: %m");
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r = -errno;
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goto finish;
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} else if (r == 0)
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break;
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r = process_event(&server, &event);
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if (r < 0)
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goto finish;
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else if (r == 0)
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break;
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}
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log_debug("systemd-kmsg-syslogd stopped as pid %lu", (unsigned long) getpid());
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finish:
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sd_notify(false,
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"STATUS=Shutting down...");
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server_done(&server);
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return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
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}
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