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-rw-r--r--src/journal/journald-syslog.c526
1 files changed, 526 insertions, 0 deletions
diff --git a/src/journal/journald-syslog.c b/src/journal/journald-syslog.c
new file mode 100644
index 0000000..ce02378
--- /dev/null
+++ b/src/journal/journald-syslog.c
@@ -0,0 +1,526 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#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) {
+
+ union sockaddr_union sa;
+
+ struct msghdr msghdr = {
+ .msg_iov = (struct iovec *) iovec,
+ .msg_iovlen = n_iovec,
+ };
+ struct cmsghdr *cmsg;
+ CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
+ const char *j;
+ int r;
+
+ assert(s);
+ assert(iovec);
+ assert(n_iovec > 0);
+
+ j = strjoina(s->runtime_directory, "/syslog");
+ r = sockaddr_un_set_path(&sa.un, j);
+ if (r < 0) {
+ log_debug_errno(r, "Forwarding socket path %s too long for AF_UNIX, not forwarding: %m", j);
+ return;
+ }
+
+ msghdr.msg_name = &sa.sa;
+ msghdr.msg_namelen = r;
+
+ 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) {
+ (void) 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 (!ascii_isdigit(*p))
+ return 0;
+
+ break;
+
+ case LETTER:
+ if (!ascii_isalpha(*p))
+ 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, const char *syslog_socket) {
+ int r;
+
+ assert(s);
+ assert(syslog_socket);
+
+ if (s->syslog_fd < 0) {
+ union sockaddr_union sa;
+ socklen_t sa_len;
+
+ r = sockaddr_un_set_path(&sa.un, syslog_socket);
+ if (r < 0)
+ return log_error_errno(r, "Unable to use namespace path %s for AF_UNIX socket: %m", syslog_socket);
+ sa_len = r;
+
+ 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, sa_len);
+ 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 (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");
+ }
+
+ 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;
+}
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