1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2011 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 #include <sys/epoll.h>
26 #include <sys/socket.h>
28 #include "systemd/sd-messages.h"
31 #include "journald-server.h"
32 #include "journald-kmsg.h"
33 #include "journald-syslog.h"
35 void server_forward_kmsg(
38 const char *identifier,
40 struct ucred *ucred) {
42 struct iovec iovec[5];
43 char header_priority[6], header_pid[16];
45 char *ident_buf = NULL;
48 assert(priority >= 0);
49 assert(priority <= 999);
52 if (_unlikely_(LOG_PRI(priority) > s->max_level_kmsg))
55 if (_unlikely_(s->dev_kmsg_fd < 0))
58 /* Never allow messages with kernel facility to be written to
59 * kmsg, regardless where the data comes from. */
60 priority = syslog_fixup_facility(priority);
62 /* First: priority field */
63 snprintf(header_priority, sizeof(header_priority), "<%i>", priority);
64 char_array_0(header_priority);
65 IOVEC_SET_STRING(iovec[n++], header_priority);
67 /* Second: identifier and PID */
70 get_process_comm(ucred->pid, &ident_buf);
71 identifier = ident_buf;
74 snprintf(header_pid, sizeof(header_pid), "["PID_FMT"]: ", ucred->pid);
75 char_array_0(header_pid);
78 IOVEC_SET_STRING(iovec[n++], identifier);
80 IOVEC_SET_STRING(iovec[n++], header_pid);
81 } else if (identifier) {
82 IOVEC_SET_STRING(iovec[n++], identifier);
83 IOVEC_SET_STRING(iovec[n++], ": ");
87 IOVEC_SET_STRING(iovec[n++], message);
88 IOVEC_SET_STRING(iovec[n++], "\n");
90 if (writev(s->dev_kmsg_fd, iovec, n) < 0)
91 log_debug("Failed to write to /dev/kmsg for logging: %m");
96 static bool is_us(const char *pid) {
101 if (parse_pid(pid, &t) < 0)
104 return t == getpid();
107 static void dev_kmsg_record(Server *s, char *p, size_t l) {
108 struct iovec iovec[N_IOVEC_META_FIELDS + 7 + N_IOVEC_KERNEL_FIELDS + 2 + N_IOVEC_UDEV_FIELDS];
109 char *message = NULL, *syslog_priority = NULL, *syslog_pid = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *source_time = NULL;
111 unsigned n = 0, z = 0, j;
112 unsigned long long usec;
113 char *identifier = NULL, *pid = NULL, *e, *f, *k;
116 char *kernel_device = NULL;
124 e = memchr(p, ',', l);
129 r = safe_atoi(p, &priority);
130 if (r < 0 || priority < 0 || priority > 999)
133 if (s->forward_to_kmsg && (priority & LOG_FACMASK) != LOG_KERN)
138 e = memchr(p, ',', l);
143 r = safe_atou64(p, &serial);
147 if (s->kernel_seqnum) {
148 /* We already read this one? */
149 if (serial < *s->kernel_seqnum)
152 /* Did we lose any? */
153 if (serial > *s->kernel_seqnum)
154 server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %"PRIu64" kernel messages",
155 serial - *s->kernel_seqnum);
157 /* Make sure we never read this one again. Note that
158 * we always store the next message serial we expect
159 * here, simply because this makes handling the first
160 * message with serial 0 easy. */
161 *s->kernel_seqnum = serial + 1;
166 f = memchr(p, ';', l);
169 /* Kernel 3.6 has the flags field, kernel 3.5 lacks that */
170 e = memchr(p, ',', l);
175 r = safe_atollu(p, &usec);
181 e = memchr(p, '\n', l);
190 for (j = 0; l > 0 && j < N_IOVEC_KERNEL_FIELDS; j++) {
192 /* Meta data fields attached */
199 e = memchr(k, '\n', l);
205 m = cunescape_length_with_prefix(k, e - k, "_KERNEL_");
209 if (startswith(m, "_KERNEL_DEVICE="))
210 kernel_device = m + 15;
212 IOVEC_SET_STRING(iovec[n++], m);
220 struct udev_device *ud;
222 ud = udev_device_new_from_device_id(s->udev, kernel_device);
225 struct udev_list_entry *ll;
228 g = udev_device_get_devnode(ud);
230 b = strappend("_UDEV_DEVNODE=", g);
232 IOVEC_SET_STRING(iovec[n++], b);
237 g = udev_device_get_sysname(ud);
239 b = strappend("_UDEV_SYSNAME=", g);
241 IOVEC_SET_STRING(iovec[n++], b);
247 ll = udev_device_get_devlinks_list_entry(ud);
248 udev_list_entry_foreach(ll, ll) {
250 if (j > N_IOVEC_UDEV_FIELDS)
253 g = udev_list_entry_get_name(ll);
255 b = strappend("_UDEV_DEVLINK=", g);
257 IOVEC_SET_STRING(iovec[n++], b);
265 udev_device_unref(ud);
269 if (asprintf(&source_time, "_SOURCE_MONOTONIC_TIMESTAMP=%llu", usec) >= 0)
270 IOVEC_SET_STRING(iovec[n++], source_time);
272 IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=kernel");
274 if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
275 IOVEC_SET_STRING(iovec[n++], syslog_priority);
277 if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
278 IOVEC_SET_STRING(iovec[n++], syslog_facility);
280 if ((priority & LOG_FACMASK) == LOG_KERN)
281 IOVEC_SET_STRING(iovec[n++], "SYSLOG_IDENTIFIER=kernel");
283 pl -= syslog_parse_identifier((const char**) &p, &identifier, &pid);
285 /* Avoid any messages we generated ourselves via
286 * log_info() and friends. */
287 if (pid && is_us(pid))
291 syslog_identifier = strappend("SYSLOG_IDENTIFIER=", identifier);
292 if (syslog_identifier)
293 IOVEC_SET_STRING(iovec[n++], syslog_identifier);
297 syslog_pid = strappend("SYSLOG_PID=", pid);
299 IOVEC_SET_STRING(iovec[n++], syslog_pid);
303 message = cunescape_length_with_prefix(p, pl, "MESSAGE=");
305 IOVEC_SET_STRING(iovec[n++], message);
307 server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority, 0);
310 for (j = 0; j < z; j++)
311 free(iovec[j].iov_base);
314 free(syslog_priority);
315 free(syslog_identifier);
317 free(syslog_facility);
323 static int server_read_dev_kmsg(Server *s) {
324 char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
328 assert(s->dev_kmsg_fd >= 0);
330 l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1);
334 /* Old kernels who don't allow reading from /dev/kmsg
335 * return EINVAL when we try. So handle this cleanly,
336 * but don' try to ever read from it again. */
337 if (errno == EINVAL) {
338 s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
342 if (errno == EAGAIN || errno == EINTR || errno == EPIPE)
345 log_error("Failed to read from kernel: %m");
349 dev_kmsg_record(s, buffer, l);
353 int server_flush_dev_kmsg(Server *s) {
358 if (s->dev_kmsg_fd < 0)
361 if (!s->dev_kmsg_readable)
364 log_debug("Flushing /dev/kmsg...");
367 r = server_read_dev_kmsg(s);
378 static int dispatch_dev_kmsg(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
379 Server *s = userdata;
382 assert(fd == s->dev_kmsg_fd);
385 if (revents & EPOLLERR)
386 log_warning("/dev/kmsg buffer overrun, some messages lost.");
388 if (!(revents & EPOLLIN))
389 log_error("Got invalid event from epoll for /dev/kmsg: %"PRIx32, revents);
391 return server_read_dev_kmsg(s);
394 int server_open_dev_kmsg(Server *s) {
399 s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
400 if (s->dev_kmsg_fd < 0) {
401 log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
402 "Failed to open /dev/kmsg, ignoring: %m");
406 r = sd_event_add_io(s->event, &s->dev_kmsg_event_source, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s);
409 /* This will fail with EPERM on older kernels where
410 * /dev/kmsg is not readable. */
416 log_error("Failed to add /dev/kmsg fd to event loop: %s", strerror(-r));
420 r = sd_event_source_set_priority(s->dev_kmsg_event_source, SD_EVENT_PRIORITY_IMPORTANT+10);
422 log_error("Failed to adjust priority of kmsg event source: %s", strerror(-r));
426 s->dev_kmsg_readable = true;
431 s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
432 s->dev_kmsg_fd = safe_close(s->dev_kmsg_fd);
437 int server_open_kernel_seqnum(Server *s) {
438 _cleanup_close_ int fd;
443 /* We store the seqnum we last read in an mmaped file. That
444 * way we can just use it like a variable, but it is
445 * persistent and automatically flushed at reboot. */
447 fd = open("/run/systemd/journal/kernel-seqnum", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644);
449 log_error("Failed to open /run/systemd/journal/kernel-seqnum, ignoring: %m");
453 if (posix_fallocate(fd, 0, sizeof(uint64_t)) < 0) {
454 log_error("Failed to allocate sequential number file, ignoring: %m");
458 p = mmap(NULL, sizeof(uint64_t), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
459 if (p == MAP_FAILED) {
460 log_error("Failed to map sequential number file, ignoring: %m");
464 s->kernel_seqnum = p;