picnoir/Systemd
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity
Systemd/src/journal/journald-kmsg.c
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate 
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

465 lines
14 KiB
C
Raw Blame History

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
***/
#include <fcntl.h>
#include <sys/epoll.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <unistd.h>
#include "libudev.h"
#include "sd-messages.h"
#include "alloc-util.h"
#include "escape.h"
#include "fd-util.h"
#include "format-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) {
_cleanup_free_ char *ident_buf = NULL;
struct iovec iovec[5];
char header_priority[DECIMAL_STR_MAX(priority) + 3],
header_pid[STRLEN("[]: ") + DECIMAL_STR_MAX(pid_t) + 1];
int n = 0;
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[n++] = IOVEC_MAKE_STRING(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[n++] = IOVEC_MAKE_STRING(identifier);
iovec[n++] = IOVEC_MAKE_STRING(header_pid);
} else if (identifier) {
iovec[n++] = IOVEC_MAKE_STRING(identifier);
iovec[n++] = IOVEC_MAKE_STRING(": ");
}
/* Fourth: message */
iovec[n++] = IOVEC_MAKE_STRING(message);
iovec[n++] = IOVEC_MAKE_STRING("\n");
if (writev(s->dev_kmsg_fd, iovec, n) < 0)
log_debug_errno(errno, "Failed to write to /dev/kmsg for logging: %m");
}
static bool is_us(const char *identifier, const char *pid) {
pid_t pid_num;
if (!identifier || !pid)
return false;
if (parse_pid(pid, &pid_num) < 0)
return false;
return pid_num == getpid_cached() &&
streq(identifier, program_invocation_short_name);
}
static void dev_kmsg_record(Server *s, const char *p, size_t l) {
_cleanup_free_ char *message = NULL, *syslog_priority = NULL, *syslog_pid = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *source_time = NULL, *identifier = NULL, *pid = NULL;
struct iovec iovec[N_IOVEC_META_FIELDS + 7 + N_IOVEC_KERNEL_FIELDS + 2 + N_IOVEC_UDEV_FIELDS];
char *kernel_device = NULL;
unsigned long long usec;
size_t n = 0, z = 0, j;
int priority, r;
char *e, *f, *k;
uint64_t serial;
size_t pl;
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 && LOG_FAC(priority) != 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, 0,
"MESSAGE_ID=" SD_MESSAGE_JOURNAL_MISSED_STR,
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[n++] = IOVEC_MAKE_STRING(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[n++] = IOVEC_MAKE_STRING(b);
z++;
}
}
g = udev_device_get_sysname(ud);
if (g) {
b = strappend("_UDEV_SYSNAME=", g);
if (b) {
iovec[n++] = IOVEC_MAKE_STRING(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[n++] = IOVEC_MAKE_STRING(b);
z++;
}
}
j++;
}
udev_device_unref(ud);
}
}
if (asprintf(&source_time, "_SOURCE_MONOTONIC_TIMESTAMP=%llu", usec) >= 0)
iovec[n++] = IOVEC_MAKE_STRING(source_time);
iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=kernel");
if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
if (LOG_FAC(priority) == LOG_KERN)
iovec[n++] = IOVEC_MAKE_STRING("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 (is_us(identifier, pid))
goto finish;
if (identifier) {
syslog_identifier = strappend("SYSLOG_IDENTIFIER=", identifier);
if (syslog_identifier)
iovec[n++] = IOVEC_MAKE_STRING(syslog_identifier);
}
if (pid) {
syslog_pid = strappend("SYSLOG_PID=", pid);
if (syslog_pid)
iovec[n++] = IOVEC_MAKE_STRING(syslog_pid);
}
}
if (cunescape_length_with_prefix(p, pl, "MESSAGE=", UNESCAPE_RELAX, &message) >= 0)
iovec[n++] = IOVEC_MAKE_STRING(message);
server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, priority, 0);
finish:
for (j = 0; j < z; j++)
free(iovec[j].iov_base);
}
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 (IN_SET(errno, EAGAIN, EINTR, 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) {
mode_t mode;
int r;
assert(s);
if (s->read_kmsg)
mode = O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY;
else
mode = O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY;
s->dev_kmsg_fd = open("/dev/kmsg", mode);
if (s->dev_kmsg_fd < 0) {
log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
"Failed to open /dev/kmsg, ignoring: %m");
return 0;
}
if (!s->read_kmsg)
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;
}
Reference in a new issue View git blame Copy permalink