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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <stddef.h>
#include <sys/epoll.h>
#include <unistd.h>
#include "sd-messages.h"
#include "alloc-util.h"
#include "fd-util.h"
#include "format-util.h"
#include "io-util.h"
#include "journald-console.h"
#include "journald-kmsg.h"
#include "journald-server.h"
#include "journald-syslog.h"
#include "journald-wall.h"
#include "process-util.h"
#include "selinux-util.h"
#include "socket-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "syslog-util.h"
/* Warn once every 30s if we missed syslog message */
#define WARN_FORWARD_SYSLOG_MISSED_USEC (30 * USEC_PER_SEC)
static void forward_syslog_iovec(Server *s, const struct iovec *iovec, unsigned n_iovec, const struct ucred *ucred, const struct timeval *tv) {
static const union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/syslog",
};
struct msghdr msghdr = {
.msg_iov = (struct iovec *) iovec,
.msg_iovlen = n_iovec,
.msg_name = (struct sockaddr*) &sa.sa,
.msg_namelen = SOCKADDR_UN_LEN(sa.un),
};
struct cmsghdr *cmsg;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
} control;
assert(s);
assert(iovec);
assert(n_iovec > 0);
if (ucred) {
zero(control);
msghdr.msg_control = &control;
msghdr.msg_controllen = sizeof(control);
cmsg = CMSG_FIRSTHDR(&msghdr);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_CREDENTIALS;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
memcpy(CMSG_DATA(cmsg), ucred, sizeof(struct ucred));
msghdr.msg_controllen = cmsg->cmsg_len;
}
/* Forward the syslog message we received via /dev/log to
* /run/systemd/syslog. Unfortunately we currently can't set
* the SO_TIMESTAMP auxiliary data, and hence we don't. */
if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
return;
/* The socket is full? I guess the syslog implementation is
* too slow, and we shouldn't wait for that... */
if (errno == EAGAIN) {
s->n_forward_syslog_missed++;
return;
}
if (ucred && IN_SET(errno, ESRCH, EPERM)) {
struct ucred u;
/* Hmm, presumably the sender process vanished
* by now, or we don't have CAP_SYS_AMDIN, so
* let's fix it as good as we can, and retry */
u = *ucred;
u.pid = getpid_cached();
memcpy(CMSG_DATA(cmsg), &u, sizeof(struct ucred));
if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
return;
if (errno == EAGAIN) {
s->n_forward_syslog_missed++;
return;
}
}
if (errno != ENOENT)
log_debug_errno(errno, "Failed to forward syslog message: %m");
}
static void forward_syslog_raw(Server *s, int priority, const char *buffer, size_t buffer_len, const struct ucred *ucred, const struct timeval *tv) {
struct iovec iovec;
assert(s);
assert(buffer);
if (LOG_PRI(priority) > s->max_level_syslog)
return;
iovec = IOVEC_MAKE((char *) buffer, buffer_len);
forward_syslog_iovec(s, &iovec, 1, ucred, tv);
}
void server_forward_syslog(Server *s, int priority, const char *identifier, const char *message, const struct ucred *ucred, const struct timeval *tv) {
struct iovec iovec[5];
char header_priority[DECIMAL_STR_MAX(priority) + 3], header_time[64],
header_pid[STRLEN("[]: ") + DECIMAL_STR_MAX(pid_t) + 1];
int n = 0;
time_t t;
struct tm tm;
_cleanup_free_ char *ident_buf = NULL;
assert(s);
assert(priority >= 0);
assert(priority <= 999);
assert(message);
if (LOG_PRI(priority) > s->max_level_syslog)
return;
/* First: priority field */
xsprintf(header_priority, "<%i>", priority);
iovec[n++] = IOVEC_MAKE_STRING(header_priority);
/* Second: timestamp */
t = tv ? tv->tv_sec : ((time_t) (now(CLOCK_REALTIME) / USEC_PER_SEC));
if (!localtime_r(&t, &tm))
return;
if (strftime(header_time, sizeof(header_time), "%h %e %T ", &tm) <= 0)
return;
iovec[n++] = IOVEC_MAKE_STRING(header_time);
/* Third: 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);
forward_syslog_iovec(s, iovec, n, ucred, tv);
}
int syslog_fixup_facility(int priority) {
if ((priority & LOG_FACMASK) == 0)
return (priority & LOG_PRIMASK) | LOG_USER;
return priority;
}
size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid) {
const char *p;
char *t;
size_t l, e;
assert(buf);
assert(identifier);
assert(pid);
p = *buf;
p += strspn(p, WHITESPACE);
l = strcspn(p, WHITESPACE);
if (l <= 0 ||
p[l-1] != ':')
return 0;
e = l;
l--;
if (l > 0 && p[l-1] == ']') {
size_t k = l-1;
for (;;) {
if (p[k] == '[') {
t = strndup(p+k+1, l-k-2);
if (t)
*pid = t;
l = k;
break;
}
if (k == 0)
break;
k--;
}
}
t = strndup(p, l);
if (t)
*identifier = t;
/* Single space is used as separator */
if (p[e] != '\0' && strchr(WHITESPACE, p[e]))
e++;
l = (p - *buf) + e;
*buf = p + e;
return l;
}
static int syslog_skip_timestamp(const char **buf) {
enum {
LETTER,
SPACE,
NUMBER,
SPACE_OR_NUMBER,
COLON
} sequence[] = {
LETTER, LETTER, LETTER,
SPACE,
SPACE_OR_NUMBER, NUMBER,
SPACE,
SPACE_OR_NUMBER, NUMBER,
COLON,
SPACE_OR_NUMBER, NUMBER,
COLON,
SPACE_OR_NUMBER, NUMBER,
SPACE
};
const char *p, *t;
unsigned i;
assert(buf);
assert(*buf);
for (i = 0, p = *buf; i < ELEMENTSOF(sequence); i++, p++) {
if (!*p)
return 0;
switch (sequence[i]) {
case SPACE:
if (*p != ' ')
return 0;
break;
case SPACE_OR_NUMBER:
if (*p == ' ')
break;
_fallthrough_;
case NUMBER:
if (*p < '0' || *p > '9')
return 0;
break;
case LETTER:
if (!(*p >= 'A' && *p <= 'Z') &&
!(*p >= 'a' && *p <= 'z'))
return 0;
break;
case COLON:
if (*p != ':')
return 0;
break;
}
}
t = *buf;
*buf = p;
return p - t;
}
void server_process_syslog_message(
Server *s,
const char *buf,
size_t raw_len,
const struct ucred *ucred,
const struct timeval *tv,
const char *label,
size_t label_len) {
char *t, syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(int)];
const char *msg, *syslog_ts, *a;
_cleanup_free_ char *identifier = NULL, *pid = NULL,
*dummy = NULL, *msg_msg = NULL, *msg_raw = NULL;
int priority = LOG_USER | LOG_INFO, r;
ClientContext *context = NULL;
struct iovec *iovec;
size_t n = 0, m, i, leading_ws, syslog_ts_len;
bool store_raw;
assert(s);
assert(buf);
/* The message cannot be empty. */
assert(raw_len > 0);
/* The buffer NUL-terminated and can be used a string. raw_len is the length
* without the terminating NUL byte, the buffer is actually one bigger. */
assert(buf[raw_len] == '\0');
if (ucred && pid_is_valid(ucred->pid)) {
r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
if (r < 0)
log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
}
/* We are creating a copy of the message because we want to forward the original message
verbatim to the legacy syslog implementation */
for (i = raw_len; i > 0; i--)
if (!strchr(WHITESPACE, buf[i-1]))
break;
leading_ws = strspn(buf, WHITESPACE);
if (i == 0)
/* The message contains only whitespaces */
msg = buf + raw_len;
else if (i == raw_len)
/* Nice! No need to strip anything on the end, let's optimize this a bit */
msg = buf + leading_ws;
else {
msg = dummy = new(char, i - leading_ws + 1);
if (!dummy) {
log_oom();
return;
}
memcpy(dummy, buf + leading_ws, i - leading_ws);
dummy[i - leading_ws] = 0;
}
/* We will add the SYSLOG_RAW= field when we stripped anything
* _or_ if the input message contained NUL bytes. */
store_raw = msg != buf || strlen(msg) != raw_len;
syslog_parse_priority(&msg, &priority, true);
if (!client_context_test_priority(context, priority))
return;
syslog_ts = msg;
syslog_ts_len = syslog_skip_timestamp(&msg);
if (syslog_ts_len == 0)
/* We failed to parse the full timestamp, store the raw message too */
store_raw = true;
syslog_parse_identifier(&msg, &identifier, &pid);
if (s->forward_to_syslog)
forward_syslog_raw(s, priority, buf, raw_len, ucred, tv);
if (s->forward_to_kmsg)
server_forward_kmsg(s, priority, identifier, msg, ucred);
if (s->forward_to_console)
server_forward_console(s, priority, identifier, msg, ucred);
if (s->forward_to_wall)
server_forward_wall(s, priority, identifier, msg, ucred);
m = N_IOVEC_META_FIELDS + 8 + client_context_extra_fields_n_iovec(context);
iovec = newa(struct iovec, m);
iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=syslog");
xsprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
if (priority & LOG_FACMASK) {
xsprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
}
if (identifier) {
a = strjoina("SYSLOG_IDENTIFIER=", identifier);
iovec[n++] = IOVEC_MAKE_STRING(a);
}
if (pid) {
a = strjoina("SYSLOG_PID=", pid);
iovec[n++] = IOVEC_MAKE_STRING(a);
}
if (syslog_ts_len > 0) {
const size_t hlen = STRLEN("SYSLOG_TIMESTAMP=");
t = newa(char, hlen + syslog_ts_len);
memcpy(t, "SYSLOG_TIMESTAMP=", hlen);
memcpy(t + hlen, syslog_ts, syslog_ts_len);
iovec[n++] = IOVEC_MAKE(t, hlen + syslog_ts_len);
}
msg_msg = strjoin("MESSAGE=", msg);
if (!msg_msg) {
log_oom();
return;
}
iovec[n++] = IOVEC_MAKE_STRING(msg_msg);
if (store_raw) {
const size_t hlen = STRLEN("SYSLOG_RAW=");
msg_raw = new(char, hlen + raw_len);
if (!msg_raw) {
log_oom();
return;
}
memcpy(msg_raw, "SYSLOG_RAW=", hlen);
memcpy(msg_raw + hlen, buf, raw_len);
iovec[n++] = IOVEC_MAKE(msg_raw, hlen + raw_len);
}
server_dispatch_message(s, iovec, n, m, context, tv, priority, 0);
}
int server_open_syslog_socket(Server *s) {
static const union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/dev-log",
};
int r;
assert(s);
if (s->syslog_fd < 0) {
s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (s->syslog_fd < 0)
return log_error_errno(errno, "socket() failed: %m");
(void) sockaddr_un_unlink(&sa.un);
r = bind(s->syslog_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
if (r < 0)
return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
(void) chmod(sa.un.sun_path, 0666);
} else
(void) fd_nonblock(s->syslog_fd, true);
r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, true);
if (r < 0)
return log_error_errno(r, "SO_PASSCRED failed: %m");
#if HAVE_SELINUX
if (mac_selinux_use()) {
r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, true);
if (r < 0)
log_warning_errno(r, "SO_PASSSEC failed: %m");
}
#endif
r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, true);
if (r < 0)
return log_error_errno(r, "SO_TIMESTAMP failed: %m");
r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
if (r < 0)
return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
r = sd_event_source_set_priority(s->syslog_event_source, SD_EVENT_PRIORITY_NORMAL+5);
if (r < 0)
return log_error_errno(r, "Failed to adjust syslog event source priority: %m");
return 0;
}
void server_maybe_warn_forward_syslog_missed(Server *s) {
usec_t n;
assert(s);
if (s->n_forward_syslog_missed <= 0)
return;
n = now(CLOCK_MONOTONIC);
if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
return;
server_driver_message(s, 0,
"MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
LOG_MESSAGE("Forwarding to syslog missed %u messages.",
s->n_forward_syslog_missed),
NULL);
s->n_forward_syslog_missed = 0;
s->last_warn_forward_syslog_missed = n;
}