1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
3 #include <sys/socket.h>
12 #include <sys/epoll.h>
20 #define STREAM_BUFFER 2048
21 #define STREAMS_MAX 256
22 #define SERVER_FD_START 3
23 #define SERVER_FD_MAX 16
24 #define TIMEOUT ((int) (10*MSEC_PER_SEC))
26 typedef struct Stream Stream;
28 typedef struct Server {
35 LIST_HEAD(Stream, streams);
39 typedef enum StreamState {
46 typedef enum LogTarget {
64 char buffer[STREAM_BUFFER];
67 LIST_FIELDS(Stream, stream);
70 #define IOVEC_SET_STRING(iovec, s) \
72 (iovec).iov_base = s; \
73 (iovec).iov_len = strlen(s); \
76 static int stream_log(Stream *s, char *p, usec_t timestamp) {
78 char header_priority[16], header_time[64], header_pid[16];
80 struct iovec iovec[5];
89 * The format glibc uses to talk to the syslog daemon is:
91 * <priority>time process[pid]: msg
93 * The format the kernel uses is:
97 * We extend the latter to include the process name and pid.
100 snprintf(header_priority, sizeof(header_priority), "<%i>",
101 s->target == LOG_TARGET_SYSLOG ? s->priority : LOG_PRI(s->priority));
102 char_array_0(header_priority);
104 if (s->target == LOG_TARGET_SYSLOG) {
108 t = (time_t) (timestamp / USEC_PER_SEC);
109 if (!(tm = localtime(&t)))
112 if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
116 snprintf(header_pid, sizeof(header_pid), "[%llu]: ", (unsigned long long) s->pid);
117 char_array_0(header_pid);
120 IOVEC_SET_STRING(iovec[0], header_priority);
122 if (s->target == LOG_TARGET_SYSLOG) {
123 IOVEC_SET_STRING(iovec[1], header_time);
124 IOVEC_SET_STRING(iovec[2], s->process);
125 IOVEC_SET_STRING(iovec[3], header_pid);
126 IOVEC_SET_STRING(iovec[4], p);
129 msghdr.msg_iov = iovec;
130 msghdr.msg_iovlen = ELEMENTSOF(iovec);
132 if (sendmsg(s->server->syslog_fd, &msghdr, MSG_NOSIGNAL) < 0)
135 } else if (s->target == LOG_TARGET_KMSG) {
136 IOVEC_SET_STRING(iovec[1], s->process);
137 IOVEC_SET_STRING(iovec[2], header_pid);
138 IOVEC_SET_STRING(iovec[3], p);
139 IOVEC_SET_STRING(iovec[4], "\n");
141 if (writev(s->server->kmsg_fd, iovec, ELEMENTSOF(iovec)) < 0)
144 assert_not_reached("Unknown log target");
149 static int stream_line(Stream *s, char *p, usec_t timestamp) {
159 case STREAM_LOG_TARGET:
160 if (streq(p, "syslog"))
161 s->target = LOG_TARGET_SYSLOG;
162 else if (streq(p, "kmsg")) {
164 if (s->server->kmsg_fd >= 0 && s->uid == 0)
165 s->target = LOG_TARGET_KMSG;
167 log_warning("/dev/kmsg logging not available.");
171 log_warning("Failed to parse log target line.");
174 s->state = STREAM_PRIORITY;
177 case STREAM_PRIORITY:
178 if ((r = safe_atoi(p, &s->priority)) < 0) {
179 log_warning("Failed to parse log priority line: %s", strerror(errno));
183 if (s->priority < 0) {
184 log_warning("Log priority negative: %s", strerror(errno));
188 s->state = STREAM_PROCESS;
192 if (!(s->process = strdup(p)))
195 s->state = STREAM_RUNNING;
199 return stream_log(s, p, timestamp);
202 assert_not_reached("Unknown stream state");
205 static int stream_scan(Stream *s, usec_t timestamp) {
213 remaining = s->length;
217 if (!(newline = memchr(p, '\n', remaining)))
222 if ((r = stream_line(s, p, timestamp)) >= 0) {
223 remaining -= newline-p+1;
229 memmove(s->buffer, p, remaining);
230 s->length = remaining;
236 static int stream_process(Stream *s, usec_t timestamp) {
241 if ((l = read(s->fd, s->buffer+s->length, STREAM_BUFFER-s->length)) < 0) {
246 log_warning("Failed to read from stream: %s", strerror(errno));
255 r = stream_scan(s, timestamp);
263 static void stream_free(Stream *s) {
267 assert(s->server->n_streams > 0);
268 s->server->n_streams--;
269 LIST_REMOVE(Stream, stream, s->server->streams, s);
275 epoll_ctl(s->server->epoll_fd, EPOLL_CTL_DEL, s->fd, NULL);
277 assert_se(close_nointr(s->fd) == 0);
284 static int stream_new(Server *s, int server_fd) {
288 socklen_t len = sizeof(ucred);
289 struct epoll_event ev;
294 if ((fd = accept4(server_fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC)) < 0)
297 if (s->n_streams >= STREAMS_MAX) {
298 log_warning("Too many connections, refusing connection.");
299 assert_se(close_nointr(fd) == 0);
303 if (!(stream = new0(Stream, 1))) {
304 assert_se(close_nointr(fd) == 0);
310 if (getsockopt(stream->fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len) < 0) {
315 if (shutdown(fd, SHUT_WR) < 0) {
321 ev.data.ptr = stream;
323 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
328 stream->pid = ucred.pid;
329 stream->uid = ucred.uid;
332 LIST_PREPEND(Stream, stream, s->streams, stream);
342 static int verify_environment(unsigned *n_sockets) {
343 unsigned long long pid;
348 assert_se(n_sockets);
350 if (!(e = getenv("LISTEN_PID"))) {
351 log_error("Missing $LISTEN_PID environment variable.");
355 if ((r = safe_atollu(e, &pid)) < 0) {
356 log_error("Failed to parse $LISTEN_PID: %s", strerror(-r));
360 if (pid != (unsigned long long) getpid()) {
361 log_error("Socket nor for me.");
365 if (!(e = getenv("LISTEN_FDS"))) {
366 log_error("Missing $LISTEN_FDS environment variable.");
370 if ((r = safe_atou(e, &ns)) < 0) {
371 log_error("Failed to parse $LISTEN_FDS: %s", strerror(-r));
375 if (ns <= 0 || ns > SERVER_FD_MAX) {
376 log_error("Wrong number of file descriptors passed: %s", e);
385 static void server_done(Server *s) {
390 stream_free(s->streams);
392 for (i = 0; i < s->n_server_fd; i++)
393 assert_se(close_nointr(SERVER_FD_START+i) == 0);
395 if (s->syslog_fd >= 0)
396 assert_se(close_nointr(s->syslog_fd) == 0);
398 if (s->epoll_fd >= 0)
399 assert_se(close_nointr(s->epoll_fd) == 0);
402 assert_se(close_nointr(s->kmsg_fd) == 0);
405 static int server_init(Server *s, unsigned n_sockets) {
410 struct sockaddr_un un;
414 assert(n_sockets > 0);
418 s->n_server_fd = n_sockets;
422 if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
424 log_error("Failed to create epoll object: %s", strerror(errno));
428 for (i = 0; i < n_sockets; i++) {
429 struct epoll_event ev;
433 ev.data.ptr = UINT_TO_PTR(SERVER_FD_START+i);
434 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, SERVER_FD_START+i, &ev) < 0) {
436 log_error("Failed to add server fd to epoll object: %s", strerror(errno));
441 if ((s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
443 log_error("Failed to create log fd: %s", strerror(errno));
448 sa.un.sun_family = AF_UNIX;
449 strncpy(sa.un.sun_path, "/dev/log", sizeof(sa.un.sun_path));
451 if (connect(s->syslog_fd, &sa.sa, sizeof(sa)) < 0) {
453 log_error("Failed to connect log socket to /dev/log: %s", strerror(errno));
457 /* /dev/kmsg logging is strictly optional */
458 if ((s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0)
459 log_debug("Failed to open /dev/kmsg for logging, disabling kernel log buffer support: %s", strerror(errno));
468 static int process_event(Server *s, struct epoll_event *ev) {
473 /* Yes, this is a bit ugly, we assume that that valid pointers
474 * are > SERVER_FD_START+SERVER_FD_MAX. Which is certainly
475 * true on Linux (and probably most other OSes, too, since the
476 * first 4k usually are part of a seperate null pointer
477 * dereference page. */
479 if (PTR_TO_UINT(ev->data.ptr) >= SERVER_FD_START &&
480 PTR_TO_UINT(ev->data.ptr) < SERVER_FD_START+s->n_server_fd) {
482 if (ev->events != POLLIN) {
483 log_info("Got invalid event from epoll. (1)");
487 if ((r = stream_new(s, PTR_TO_UINT(ev->data.ptr))) < 0) {
488 log_info("Failed to accept new connection: %s", strerror(-r));
494 Stream *stream = ev->data.ptr;
496 timestamp = now(CLOCK_REALTIME);
498 if (!(ev->events & POLLIN)) {
499 log_info("Got invalid event from epoll. (3)");
504 if ((r = stream_process(stream, timestamp)) <= 0) {
507 log_info("Got error on stream: %s", strerror(-r));
517 int main(int argc, char *argv[]) {
522 log_info("systemd-logger running as pid %llu", (unsigned long long) getpid());
524 if (verify_environment(&n) < 0)
527 if (server_init(&server, n) < 0)
531 struct epoll_event event;
534 if ((n = epoll_wait(server.epoll_fd,
536 server.n_streams <= 0 ? TIMEOUT : -1)) < 0) {
541 log_error("epoll_wait() failed: %s", strerror(errno));
548 if ((r = process_event(&server, &event)) < 0)
554 server_done(&server);
556 log_info("systemd-logger stopped as pid %llu", (unsigned long long) getpid());