Systemd/src/journal/journald.c
Lennart Poettering e22aa3d328 journald: never block when sending messages on NOTIFY_SOCKET socket
Otherwise we might run into deadlocks, when journald blocks on the
notify socket on PID 1, and PID 1 blocks on IPC to dbus-daemon and
dbus-daemon blocks on logging to journald. Break this cycle by making
sure that journald never ever blocks on PID 1.

Note that this change disables support for event loop watchdog support,
as these messages are sent in blocking style by sd-event. That should
not be a big loss though, as people reported frequent problems with the
watchdog hitting journald on excessively slow IO.

Fixes: #1505.
2015-11-01 22:12:29 +01:00

120 lines
3.7 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 <unistd.h>
#include "sd-messages.h"
#include "sd-daemon.h"
#include "journal-authenticate.h"
#include "journald-server.h"
#include "journald-kmsg.h"
#include "journald-syslog.h"
#include "sigbus.h"
#include "formats-util.h"
int main(int argc, char *argv[]) {
Server server;
int r;
if (argc > 1) {
log_error("This program does not take arguments.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_SAFE);
log_set_facility(LOG_SYSLOG);
log_parse_environment();
log_open();
umask(0022);
sigbus_install();
r = server_init(&server);
if (r < 0)
goto finish;
server_vacuum(&server, false, false);
server_flush_to_var(&server);
server_flush_dev_kmsg(&server);
log_debug("systemd-journald running as pid "PID_FMT, getpid());
server_driver_message(&server, SD_MESSAGE_JOURNAL_START, "Journal started");
for (;;) {
usec_t t = USEC_INFINITY, n;
r = sd_event_get_state(server.event);
if (r < 0)
goto finish;
if (r == SD_EVENT_FINISHED)
break;
n = now(CLOCK_REALTIME);
if (server.max_retention_usec > 0 && server.oldest_file_usec > 0) {
/* The retention time is reached, so let's vacuum! */
if (server.oldest_file_usec + server.max_retention_usec < n) {
log_info("Retention time reached.");
server_rotate(&server);
server_vacuum(&server, false, false);
continue;
}
/* Calculate when to rotate the next time */
t = server.oldest_file_usec + server.max_retention_usec - n;
}
#ifdef HAVE_GCRYPT
if (server.system_journal) {
usec_t u;
if (journal_file_next_evolve_usec(server.system_journal, &u)) {
if (n >= u)
t = 0;
else
t = MIN(t, u - n);
}
}
#endif
r = sd_event_run(server.event, t);
if (r < 0) {
log_error_errno(r, "Failed to run event loop: %m");
goto finish;
}
server_maybe_append_tags(&server);
server_maybe_warn_forward_syslog_missed(&server);
}
log_debug("systemd-journald stopped as pid "PID_FMT, getpid());
server_driver_message(&server, SD_MESSAGE_JOURNAL_STOP, "Journal stopped");
finish:
server_done(&server);
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}