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-rw-r--r--src/grp-journal/libjournal-core/journald-kmsg.c473
1 files changed, 473 insertions, 0 deletions
diff --git a/src/grp-journal/libjournal-core/journald-kmsg.c b/src/grp-journal/libjournal-core/journald-kmsg.c
new file mode 100644
index 0000000000..3712636de2
--- /dev/null
+++ b/src/grp-journal/libjournal-core/journald-kmsg.c
@@ -0,0 +1,473 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2011 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <fcntl.h>
+#include <sys/epoll.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "libudev.h"
+#include <systemd/sd-messages.h>
+
+#include "escape.h"
+#include "fd-util.h"
+#include "formats-util.h"
+#include "io-util.h"
+#include "journald-kmsg.h"
+#include "journald-server.h"
+#include "journald-syslog.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+
+void server_forward_kmsg(
+ Server *s,
+ int priority,
+ const char *identifier,
+ const char *message,
+ const struct ucred *ucred) {
+
+ struct iovec iovec[5];
+ char header_priority[DECIMAL_STR_MAX(priority) + 3],
+ header_pid[sizeof("[]: ")-1 + DECIMAL_STR_MAX(pid_t) + 1];
+ int n = 0;
+ char *ident_buf = NULL;
+
+ assert(s);
+ assert(priority >= 0);
+ assert(priority <= 999);
+ assert(message);
+
+ if (_unlikely_(LOG_PRI(priority) > s->max_level_kmsg))
+ return;
+
+ if (_unlikely_(s->dev_kmsg_fd < 0))
+ return;
+
+ /* Never allow messages with kernel facility to be written to
+ * kmsg, regardless where the data comes from. */
+ priority = syslog_fixup_facility(priority);
+
+ /* First: priority field */
+ xsprintf(header_priority, "<%i>", priority);
+ IOVEC_SET_STRING(iovec[n++], header_priority);
+
+ /* Second: identifier and PID */
+ if (ucred) {
+ if (!identifier) {
+ get_process_comm(ucred->pid, &ident_buf);
+ identifier = ident_buf;
+ }
+
+ xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
+
+ if (identifier)
+ IOVEC_SET_STRING(iovec[n++], identifier);
+
+ IOVEC_SET_STRING(iovec[n++], header_pid);
+ } else if (identifier) {
+ IOVEC_SET_STRING(iovec[n++], identifier);
+ IOVEC_SET_STRING(iovec[n++], ": ");
+ }
+
+ /* Fourth: message */
+ IOVEC_SET_STRING(iovec[n++], message);
+ IOVEC_SET_STRING(iovec[n++], "\n");
+
+ if (writev(s->dev_kmsg_fd, iovec, n) < 0)
+ log_debug_errno(errno, "Failed to write to /dev/kmsg for logging: %m");
+
+ free(ident_buf);
+}
+
+static bool is_us(const char *pid) {
+ pid_t t;
+
+ assert(pid);
+
+ if (parse_pid(pid, &t) < 0)
+ return false;
+
+ return t == getpid();
+}
+
+static void dev_kmsg_record(Server *s, const char *p, size_t l) {
+ struct iovec iovec[N_IOVEC_META_FIELDS + 7 + N_IOVEC_KERNEL_FIELDS + 2 + N_IOVEC_UDEV_FIELDS];
+ char *message = NULL, *syslog_priority = NULL, *syslog_pid = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *source_time = NULL;
+ int priority, r;
+ unsigned n = 0, z = 0, j;
+ unsigned long long usec;
+ char *identifier = NULL, *pid = NULL, *e, *f, *k;
+ uint64_t serial;
+ size_t pl;
+ char *kernel_device = NULL;
+
+ assert(s);
+ assert(p);
+
+ if (l <= 0)
+ return;
+
+ e = memchr(p, ',', l);
+ if (!e)
+ return;
+ *e = 0;
+
+ r = safe_atoi(p, &priority);
+ if (r < 0 || priority < 0 || priority > 999)
+ return;
+
+ if (s->forward_to_kmsg && (priority & LOG_FACMASK) != LOG_KERN)
+ return;
+
+ l -= (e - p) + 1;
+ p = e + 1;
+ e = memchr(p, ',', l);
+ if (!e)
+ return;
+ *e = 0;
+
+ r = safe_atou64(p, &serial);
+ if (r < 0)
+ return;
+
+ if (s->kernel_seqnum) {
+ /* We already read this one? */
+ if (serial < *s->kernel_seqnum)
+ return;
+
+ /* Did we lose any? */
+ if (serial > *s->kernel_seqnum)
+ server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED,
+ LOG_MESSAGE("Missed %"PRIu64" kernel messages",
+ serial - *s->kernel_seqnum),
+ NULL);
+
+ /* Make sure we never read this one again. Note that
+ * we always store the next message serial we expect
+ * here, simply because this makes handling the first
+ * message with serial 0 easy. */
+ *s->kernel_seqnum = serial + 1;
+ }
+
+ l -= (e - p) + 1;
+ p = e + 1;
+ f = memchr(p, ';', l);
+ if (!f)
+ return;
+ /* Kernel 3.6 has the flags field, kernel 3.5 lacks that */
+ e = memchr(p, ',', l);
+ if (!e || f < e)
+ e = f;
+ *e = 0;
+
+ r = safe_atollu(p, &usec);
+ if (r < 0)
+ return;
+
+ l -= (f - p) + 1;
+ p = f + 1;
+ e = memchr(p, '\n', l);
+ if (!e)
+ return;
+ *e = 0;
+
+ pl = e - p;
+ l -= (e - p) + 1;
+ k = e + 1;
+
+ for (j = 0; l > 0 && j < N_IOVEC_KERNEL_FIELDS; j++) {
+ char *m;
+ /* Metadata fields attached */
+
+ if (*k != ' ')
+ break;
+
+ k++, l--;
+
+ e = memchr(k, '\n', l);
+ if (!e)
+ return;
+
+ *e = 0;
+
+ if (cunescape_length_with_prefix(k, e - k, "_KERNEL_", UNESCAPE_RELAX, &m) < 0)
+ break;
+
+ if (startswith(m, "_KERNEL_DEVICE="))
+ kernel_device = m + 15;
+
+ IOVEC_SET_STRING(iovec[n++], m);
+ z++;
+
+ l -= (e - k) + 1;
+ k = e + 1;
+ }
+
+ if (kernel_device) {
+ struct udev_device *ud;
+
+ ud = udev_device_new_from_device_id(s->udev, kernel_device);
+ if (ud) {
+ const char *g;
+ struct udev_list_entry *ll;
+ char *b;
+
+ g = udev_device_get_devnode(ud);
+ if (g) {
+ b = strappend("_UDEV_DEVNODE=", g);
+ if (b) {
+ IOVEC_SET_STRING(iovec[n++], b);
+ z++;
+ }
+ }
+
+ g = udev_device_get_sysname(ud);
+ if (g) {
+ b = strappend("_UDEV_SYSNAME=", g);
+ if (b) {
+ IOVEC_SET_STRING(iovec[n++], b);
+ z++;
+ }
+ }
+
+ j = 0;
+ ll = udev_device_get_devlinks_list_entry(ud);
+ udev_list_entry_foreach(ll, ll) {
+
+ if (j > N_IOVEC_UDEV_FIELDS)
+ break;
+
+ g = udev_list_entry_get_name(ll);
+ if (g) {
+ b = strappend("_UDEV_DEVLINK=", g);
+ if (b) {
+ IOVEC_SET_STRING(iovec[n++], b);
+ z++;
+ }
+ }
+
+ j++;
+ }
+
+ udev_device_unref(ud);
+ }
+ }
+
+ if (asprintf(&source_time, "_SOURCE_MONOTONIC_TIMESTAMP=%llu", usec) >= 0)
+ IOVEC_SET_STRING(iovec[n++], source_time);
+
+ IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=kernel");
+
+ if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
+ IOVEC_SET_STRING(iovec[n++], syslog_priority);
+
+ if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
+ IOVEC_SET_STRING(iovec[n++], syslog_facility);
+
+ if ((priority & LOG_FACMASK) == LOG_KERN)
+ IOVEC_SET_STRING(iovec[n++], "SYSLOG_IDENTIFIER=kernel");
+ else {
+ pl -= syslog_parse_identifier((const char**) &p, &identifier, &pid);
+
+ /* Avoid any messages we generated ourselves via
+ * log_info() and friends. */
+ if (pid && is_us(pid))
+ goto finish;
+
+ if (identifier) {
+ syslog_identifier = strappend("SYSLOG_IDENTIFIER=", identifier);
+ if (syslog_identifier)
+ IOVEC_SET_STRING(iovec[n++], syslog_identifier);
+ }
+
+ if (pid) {
+ syslog_pid = strappend("SYSLOG_PID=", pid);
+ if (syslog_pid)
+ IOVEC_SET_STRING(iovec[n++], syslog_pid);
+ }
+ }
+
+ if (cunescape_length_with_prefix(p, pl, "MESSAGE=", UNESCAPE_RELAX, &message) >= 0)
+ IOVEC_SET_STRING(iovec[n++], message);
+
+ server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority, 0);
+
+finish:
+ for (j = 0; j < z; j++)
+ free(iovec[j].iov_base);
+
+ free(message);
+ free(syslog_priority);
+ free(syslog_identifier);
+ free(syslog_pid);
+ free(syslog_facility);
+ free(source_time);
+ free(identifier);
+ free(pid);
+}
+
+static int server_read_dev_kmsg(Server *s) {
+ char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
+ ssize_t l;
+
+ assert(s);
+ assert(s->dev_kmsg_fd >= 0);
+
+ l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1);
+ if (l == 0)
+ return 0;
+ if (l < 0) {
+ /* Old kernels who don't allow reading from /dev/kmsg
+ * return EINVAL when we try. So handle this cleanly,
+ * but don' try to ever read from it again. */
+ if (errno == EINVAL) {
+ s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
+ return 0;
+ }
+
+ if (errno == EAGAIN || errno == EINTR || errno == EPIPE)
+ return 0;
+
+ return log_error_errno(errno, "Failed to read from kernel: %m");
+ }
+
+ dev_kmsg_record(s, buffer, l);
+ return 1;
+}
+
+int server_flush_dev_kmsg(Server *s) {
+ int r;
+
+ assert(s);
+
+ if (s->dev_kmsg_fd < 0)
+ return 0;
+
+ if (!s->dev_kmsg_readable)
+ return 0;
+
+ log_debug("Flushing /dev/kmsg...");
+
+ for (;;) {
+ r = server_read_dev_kmsg(s);
+ if (r < 0)
+ return r;
+
+ if (r == 0)
+ break;
+ }
+
+ return 0;
+}
+
+static int dispatch_dev_kmsg(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+ Server *s = userdata;
+
+ assert(es);
+ assert(fd == s->dev_kmsg_fd);
+ assert(s);
+
+ if (revents & EPOLLERR)
+ log_warning("/dev/kmsg buffer overrun, some messages lost.");
+
+ if (!(revents & EPOLLIN))
+ log_error("Got invalid event from epoll for /dev/kmsg: %"PRIx32, revents);
+
+ return server_read_dev_kmsg(s);
+}
+
+int server_open_dev_kmsg(Server *s) {
+ int r;
+
+ assert(s);
+
+ s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+ if (s->dev_kmsg_fd < 0) {
+ log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
+ "Failed to open /dev/kmsg, ignoring: %m");
+ return 0;
+ }
+
+ r = sd_event_add_io(s->event, &s->dev_kmsg_event_source, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s);
+ if (r < 0) {
+
+ /* This will fail with EPERM on older kernels where
+ * /dev/kmsg is not readable. */
+ if (r == -EPERM) {
+ r = 0;
+ goto fail;
+ }
+
+ log_error_errno(r, "Failed to add /dev/kmsg fd to event loop: %m");
+ goto fail;
+ }
+
+ r = sd_event_source_set_priority(s->dev_kmsg_event_source, SD_EVENT_PRIORITY_IMPORTANT+10);
+ if (r < 0) {
+ log_error_errno(r, "Failed to adjust priority of kmsg event source: %m");
+ goto fail;
+ }
+
+ s->dev_kmsg_readable = true;
+
+ return 0;
+
+fail:
+ s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
+ s->dev_kmsg_fd = safe_close(s->dev_kmsg_fd);
+
+ return r;
+}
+
+int server_open_kernel_seqnum(Server *s) {
+ _cleanup_close_ int fd;
+ uint64_t *p;
+ int r;
+
+ assert(s);
+
+ /* We store the seqnum we last read in an mmaped file. That
+ * way we can just use it like a variable, but it is
+ * persistent and automatically flushed at reboot. */
+
+ fd = open("/run/systemd/journal/kernel-seqnum", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644);
+ if (fd < 0) {
+ log_error_errno(errno, "Failed to open /run/systemd/journal/kernel-seqnum, ignoring: %m");
+ return 0;
+ }
+
+ r = posix_fallocate(fd, 0, sizeof(uint64_t));
+ if (r != 0) {
+ log_error_errno(r, "Failed to allocate sequential number file, ignoring: %m");
+ return 0;
+ }
+
+ p = mmap(NULL, sizeof(uint64_t), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+ if (p == MAP_FAILED) {
+ log_error_errno(errno, "Failed to map sequential number file, ignoring: %m");
+ return 0;
+ }
+
+ s->kernel_seqnum = p;
+
+ return 0;
+}
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