/*-*- 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/types.h> #include <assert.h> #include <time.h> #include <string.h> #include <stdio.h> #include <errno.h> #include <unistd.h> #include <sys/poll.h> #include <sys/epoll.h> #include <sys/un.h> #include <fcntl.h> #include <sys/signalfd.h> #include "util.h" #include "log.h" #include "sd-daemon.h" #include "fdset.h" #define SERVER_FD_MAX 16 typedef struct Stream Stream; typedef struct Server { FDSet *syslog_fds; int kmsg_fd; int epoll_fd; int signal_fd; } Server; static void server_done(Server *s) { assert(s); if (s->epoll_fd >= 0) close_nointr_nofail(s->epoll_fd); if (s->kmsg_fd >= 0) close_nointr_nofail(s->kmsg_fd); if (s->signal_fd >= 0) close_nointr_nofail(s->signal_fd); if (s->syslog_fds) fdset_free(s->syslog_fds); } static int server_init(Server *s, unsigned n_sockets) { int r; unsigned i; struct epoll_event ev; sigset_t mask; assert(s); assert(n_sockets > 0); zero(*s); s->kmsg_fd = s->signal_fd = -1; if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) { r = -errno; log_error("Failed to create epoll object: %s", strerror(errno)); goto fail; } if (!(s->syslog_fds = fdset_new())) { r = -ENOMEM; log_error("Failed to allocate file descriptor set: %s", strerror(errno)); goto fail; } for (i = 0; i < n_sockets; i++) { int fd, one = 1; fd = SD_LISTEN_FDS_START+i; if ((r = sd_is_socket(fd, AF_UNSPEC, SOCK_DGRAM, -1)) < 0) { log_error("Failed to determine file descriptor type: %s", strerror(-r)); goto fail; } if (!r) { log_error("Wrong file descriptor type."); r = -EINVAL; goto fail; } if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) log_error("SO_PASSCRED failed: %m"); zero(ev); ev.events = EPOLLIN; ev.data.fd = fd; if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) { r = -errno; log_error("Failed to add server fd to epoll object: %s", strerror(errno)); goto fail; } if ((r = fdset_put(s->syslog_fds, fd)) < 0) { log_error("Failed to store file descriptor in set: %s", strerror(-r)); goto fail; } } if ((s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0) { log_error("Failed to open /dev/kmsg for logging: %m"); return -errno; } assert_se(sigemptyset(&mask) == 0); sigset_add_many(&mask, SIGINT, SIGTERM, -1); assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); if ((s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) { log_error("signalfd(): %m"); return -errno; } zero(ev); ev.events = EPOLLIN; ev.data.fd = s->signal_fd; if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) { log_error("epoll_ctl(): %m"); return -errno; } return 0; fail: server_done(s); return r; } static void skip_date(const char **buf) { enum { LETTER, SPACE, NUMBER, SPACE_OR_NUMBER, COLON } sequence[] = { LETTER, LETTER, LETTER, SPACE, SPACE_OR_NUMBER, NUMBER, SPACE, SPACE_OR_NUMBER, NUMBER, COLON, SPACE_OR_NUMBER, NUMBER, COLON, SPACE_OR_NUMBER, NUMBER, SPACE }; const char *p; unsigned i; assert(buf); assert(*buf); p = *buf; for (i = 0; i < ELEMENTSOF(sequence); i++, p++) { if (!*p) return; switch (sequence[i]) { case SPACE: if (*p != ' ') return; break; case SPACE_OR_NUMBER: if (*p == ' ') break; /* fall through */ case NUMBER: if (*p < '0' || *p > '9') return; break; case LETTER: if (!(*p >= 'A' && *p <= 'Z') && !(*p >= 'a' && *p <= 'z')) return; break; case COLON: if (*p != ':') return; break; } } *buf = p; } static int read_process(const char **buf, struct iovec *iovec) { const char *p; size_t l; assert(buf); assert(*buf); assert(iovec); p = *buf; p += strspn(p, WHITESPACE); l = strcspn(p, WHITESPACE); if (l <= 0 || p[l-1] != ':') return 0; l--; if (p[l-1] == ']') { size_t k = l-1; for (;;) { if (p[k] == '[') { l = k; break; } if (k == 0) break; k--; } } iovec->iov_base = (char*) p; iovec->iov_len = l; *buf = p + l; return 1; } static void skip_pid(const char **buf) { const char *p; assert(buf); assert(*buf); p = *buf; if (*p != '[') return; p++; p += strspn(p, "0123456789"); if (*p != ']') return; p++; *buf = p; } static int write_message(Server *s, const char *buf, struct ucred *ucred) { ssize_t k; char priority[6], pid[16]; struct iovec iovec[5]; unsigned i = 0; char *process = NULL; int r = 0; int prio = LOG_USER | LOG_INFO; assert(s); assert(buf); parse_syslog_priority((char**) &buf, &prio); if (*buf == 0) return 0; if ((prio & LOG_FACMASK) == 0) prio = LOG_USER | LOG_PRI(prio); /* First, set priority field */ snprintf(priority, sizeof(priority), "<%i>", prio); char_array_0(priority); IOVEC_SET_STRING(iovec[i++], priority); /* Second, skip date */ skip_date(&buf); /* Then, add process if set */ if (read_process(&buf, &iovec[i]) > 0) i++; else if (ucred && ucred->pid > 0 && get_process_name(ucred->pid, &process) >= 0) IOVEC_SET_STRING(iovec[i++], process); /* Skip the stored PID if we have a better one */ if (ucred) { snprintf(pid, sizeof(pid), "[%lu]: ", (unsigned long) ucred->pid); char_array_0(pid); IOVEC_SET_STRING(iovec[i++], pid); skip_pid(&buf); if (*buf == ':') buf++; buf += strspn(buf, WHITESPACE); } /* Is the remaining message empty? */ if (*buf) { /* And the rest is the message */ IOVEC_SET_STRING(iovec[i++], buf); IOVEC_SET_STRING(iovec[i++], "\n"); if ((k = writev(s->kmsg_fd, iovec, i)) <= 0) { log_error("Failed to write log message to kmsg: %s", k < 0 ? strerror(errno) : "short write"); r = k < 0 ? -errno : -EIO; } } free(process); return r; } static int process_event(Server *s, struct epoll_event *ev) { assert(s); if (ev->events != EPOLLIN) { log_info("Got invalid event from epoll."); return -EIO; } if (ev->data.fd == s->signal_fd) { struct signalfd_siginfo sfsi; ssize_t n; if ((n = read(s->signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) { if (n >= 0) return -EIO; if (errno == EINTR || errno == EAGAIN) return 0; return -errno; } log_debug("Received SIG%s", strna(signal_to_string(sfsi.ssi_signo))); return 0; } else { for (;;) { char buf[LINE_MAX+1]; struct msghdr msghdr; struct iovec iovec; struct ucred *ucred; union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; } control; ssize_t n; int k; char *e; zero(iovec); iovec.iov_base = buf; iovec.iov_len = sizeof(buf)-1; zero(control); zero(msghdr); msghdr.msg_iov = &iovec; msghdr.msg_iovlen = 1; msghdr.msg_control = &control; msghdr.msg_controllen = sizeof(control); if ((n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT)) < 0) { if (errno == EINTR || errno == EAGAIN) return 1; log_error("recvmsg() failed: %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))) ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr); else ucred = NULL; if ((e = memchr(buf, '\n', n))) *e = 0; else buf[n] = 0; if ((k = write_message(s, strstrip(buf), ucred)) < 0) return k; } } return 1; } int main(int argc, char *argv[]) { Server server; int r = EXIT_FAILURE, n; if (getppid() != 1) { log_error("This program should be invoked by init only."); return EXIT_FAILURE; } if (argc > 1) { log_error("This program does not take arguments."); return EXIT_FAILURE; } log_set_target(LOG_TARGET_KMSG); log_parse_environment(); log_open(); if ((n = sd_listen_fds(true)) < 0) { log_error("Failed to read listening file descriptors from environment: %s", strerror(-r)); return EXIT_FAILURE; } if (n <= 0 || n > SERVER_FD_MAX) { log_error("No or too many file descriptors passed."); return EXIT_FAILURE; } if (server_init(&server, (unsigned) n) < 0) return EXIT_FAILURE; log_debug("systemd-kmsg-syslogd running as pid %lu", (unsigned long) getpid()); sd_notify(false, "READY=1\n" "STATUS=Processing messages..."); for (;;) { struct epoll_event event; int k; if ((k = epoll_wait(server.epoll_fd, &event, 1, -1)) < 0) { if (errno == EINTR) continue; log_error("epoll_wait() failed: %m"); goto fail; } if (k <= 0) break; if ((k = process_event(&server, &event)) < 0) goto fail; if (k == 0) break; } r = EXIT_SUCCESS; log_debug("systemd-kmsg-syslogd stopped as pid %lu", (unsigned long) getpid()); fail: sd_notify(false, "STATUS=Shutting down..."); server_done(&server); return r; }