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 const struct ucred *ucred) {
42 struct iovec iovec[5];
43 char header_priority[DECIMAL_STR_MAX(priority) + 3],
44 header_pid[sizeof("[]: ")-1 + DECIMAL_STR_MAX(pid_t) + 1];
46 char *ident_buf = NULL;
49 assert(priority >= 0);
50 assert(priority <= 999);
53 if (_unlikely_(LOG_PRI(priority) > s->max_level_kmsg))
56 if (_unlikely_(s->dev_kmsg_fd < 0))
59 /* Never allow messages with kernel facility to be written to
60 * kmsg, regardless where the data comes from. */
61 priority = syslog_fixup_facility(priority);
63 /* First: priority field */
64 xsprintf(header_priority, "<%i>", 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 xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
77 IOVEC_SET_STRING(iovec[n++], identifier);
79 IOVEC_SET_STRING(iovec[n++], header_pid);
80 } else if (identifier) {
81 IOVEC_SET_STRING(iovec[n++], identifier);
82 IOVEC_SET_STRING(iovec[n++], ": ");
86 IOVEC_SET_STRING(iovec[n++], message);
87 IOVEC_SET_STRING(iovec[n++], "\n");
89 if (writev(s->dev_kmsg_fd, iovec, n) < 0)
90 log_debug_errno(errno, "Failed to write to /dev/kmsg for logging: %m");
95 static bool is_us(const char *pid) {
100 if (parse_pid(pid, &t) < 0)
103 return t == getpid();
106 static void dev_kmsg_record(Server *s, const char *p, size_t l) {
107 struct iovec iovec[N_IOVEC_META_FIELDS + 7 + N_IOVEC_KERNEL_FIELDS + 2 + N_IOVEC_UDEV_FIELDS];
108 char *message = NULL, *syslog_priority = NULL, *syslog_pid = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *source_time = NULL;
110 unsigned n = 0, z = 0, j;
111 unsigned long long usec;
112 char *identifier = NULL, *pid = NULL, *e, *f, *k;
115 char *kernel_device = NULL;
123 e = memchr(p, ',', l);
128 r = safe_atoi(p, &priority);
129 if (r < 0 || priority < 0 || priority > 999)
132 if (s->forward_to_kmsg && (priority & LOG_FACMASK) != LOG_KERN)
137 e = memchr(p, ',', l);
142 r = safe_atou64(p, &serial);
146 if (s->kernel_seqnum) {
147 /* We already read this one? */
148 if (serial < *s->kernel_seqnum)
151 /* Did we lose any? */
152 if (serial > *s->kernel_seqnum)
153 server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %"PRIu64" kernel messages",
154 serial - *s->kernel_seqnum);
156 /* Make sure we never read this one again. Note that
157 * we always store the next message serial we expect
158 * here, simply because this makes handling the first
159 * message with serial 0 easy. */
160 *s->kernel_seqnum = serial + 1;
165 f = memchr(p, ';', l);
168 /* Kernel 3.6 has the flags field, kernel 3.5 lacks that */
169 e = memchr(p, ',', l);
174 r = safe_atollu(p, &usec);
180 e = memchr(p, '\n', l);
189 for (j = 0; l > 0 && j < N_IOVEC_KERNEL_FIELDS; j++) {
191 /* Meta data fields attached */
198 e = memchr(k, '\n', l);
204 m = cunescape_length_with_prefix(k, e - k, "_KERNEL_");
208 if (startswith(m, "_KERNEL_DEVICE="))
209 kernel_device = m + 15;
211 IOVEC_SET_STRING(iovec[n++], m);
219 struct udev_device *ud;
221 ud = udev_device_new_from_device_id(s->udev, kernel_device);
224 struct udev_list_entry *ll;
227 g = udev_device_get_devnode(ud);
229 b = strappend("_UDEV_DEVNODE=", g);
231 IOVEC_SET_STRING(iovec[n++], b);
236 g = udev_device_get_sysname(ud);
238 b = strappend("_UDEV_SYSNAME=", g);
240 IOVEC_SET_STRING(iovec[n++], b);
246 ll = udev_device_get_devlinks_list_entry(ud);
247 udev_list_entry_foreach(ll, ll) {
249 if (j > N_IOVEC_UDEV_FIELDS)
252 g = udev_list_entry_get_name(ll);
254 b = strappend("_UDEV_DEVLINK=", g);
256 IOVEC_SET_STRING(iovec[n++], b);
264 udev_device_unref(ud);
268 if (asprintf(&source_time, "_SOURCE_MONOTONIC_TIMESTAMP=%llu", usec) >= 0)
269 IOVEC_SET_STRING(iovec[n++], source_time);
271 IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=kernel");
273 if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
274 IOVEC_SET_STRING(iovec[n++], syslog_priority);
276 if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
277 IOVEC_SET_STRING(iovec[n++], syslog_facility);
279 if ((priority & LOG_FACMASK) == LOG_KERN)
280 IOVEC_SET_STRING(iovec[n++], "SYSLOG_IDENTIFIER=kernel");
282 pl -= syslog_parse_identifier((const char**) &p, &identifier, &pid);
284 /* Avoid any messages we generated ourselves via
285 * log_info() and friends. */
286 if (pid && is_us(pid))
290 syslog_identifier = strappend("SYSLOG_IDENTIFIER=", identifier);
291 if (syslog_identifier)
292 IOVEC_SET_STRING(iovec[n++], syslog_identifier);
296 syslog_pid = strappend("SYSLOG_PID=", pid);
298 IOVEC_SET_STRING(iovec[n++], syslog_pid);
302 message = cunescape_length_with_prefix(p, pl, "MESSAGE=");
304 IOVEC_SET_STRING(iovec[n++], message);
306 server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority, 0);
309 for (j = 0; j < z; j++)
310 free(iovec[j].iov_base);
313 free(syslog_priority);
314 free(syslog_identifier);
316 free(syslog_facility);
322 static int server_read_dev_kmsg(Server *s) {
323 char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
327 assert(s->dev_kmsg_fd >= 0);
329 l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1);
333 /* Old kernels who don't allow reading from /dev/kmsg
334 * return EINVAL when we try. So handle this cleanly,
335 * but don' try to ever read from it again. */
336 if (errno == EINVAL) {
337 s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
341 if (errno == EAGAIN || errno == EINTR || errno == EPIPE)
344 log_error_errno(errno, "Failed to read from kernel: %m");
348 dev_kmsg_record(s, buffer, l);
352 int server_flush_dev_kmsg(Server *s) {
357 if (s->dev_kmsg_fd < 0)
360 if (!s->dev_kmsg_readable)
363 log_debug("Flushing /dev/kmsg...");
366 r = server_read_dev_kmsg(s);
377 static int dispatch_dev_kmsg(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
378 Server *s = userdata;
381 assert(fd == s->dev_kmsg_fd);
384 if (revents & EPOLLERR)
385 log_warning("/dev/kmsg buffer overrun, some messages lost.");
387 if (!(revents & EPOLLIN))
388 log_error("Got invalid event from epoll for /dev/kmsg: %"PRIx32, revents);
390 return server_read_dev_kmsg(s);
393 int server_open_dev_kmsg(Server *s) {
398 s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
399 if (s->dev_kmsg_fd < 0) {
400 log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
401 "Failed to open /dev/kmsg, ignoring: %m");
405 r = sd_event_add_io(s->event, &s->dev_kmsg_event_source, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s);
408 /* This will fail with EPERM on older kernels where
409 * /dev/kmsg is not readable. */
415 log_error_errno(r, "Failed to add /dev/kmsg fd to event loop: %m");
419 r = sd_event_source_set_priority(s->dev_kmsg_event_source, SD_EVENT_PRIORITY_IMPORTANT+10);
421 log_error_errno(r, "Failed to adjust priority of kmsg event source: %m");
425 s->dev_kmsg_readable = true;
430 s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
431 s->dev_kmsg_fd = safe_close(s->dev_kmsg_fd);
436 int server_open_kernel_seqnum(Server *s) {
437 _cleanup_close_ int fd;
442 /* We store the seqnum we last read in an mmaped file. That
443 * way we can just use it like a variable, but it is
444 * persistent and automatically flushed at reboot. */
446 fd = open("/run/systemd/journal/kernel-seqnum", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644);
448 log_error_errno(errno, "Failed to open /run/systemd/journal/kernel-seqnum, ignoring: %m");
452 if (posix_fallocate(fd, 0, sizeof(uint64_t)) < 0) {
453 log_error_errno(errno, "Failed to allocate sequential number file, ignoring: %m");
457 p = mmap(NULL, sizeof(uint64_t), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
458 if (p == MAP_FAILED) {
459 log_error_errno(errno, "Failed to map sequential number file, ignoring: %m");
463 s->kernel_seqnum = p;