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journald: rebreak a few comments

This commit is contained in:
Lennart Poettering 2019-04-05 15:31:18 +02:00
parent e3d78cb160
commit 337fabf749
1 changed files with 18 additions and 28 deletions
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46
src/journal/journald-server.c
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@ -1421,14 +1421,13 @@ static int setup_signals(Server *s) {
if (r < 0)
return r;
/* Let's process SIGTERM late, so that we flush all queued
* messages to disk before we exit */
/* Let's process SIGTERM late, so that we flush all queued messages to disk before we exit */
r = sd_event_source_set_priority(s->sigterm_event_source, SD_EVENT_PRIORITY_NORMAL+20);
if (r < 0)
return r;
/* When journald is invoked on the terminal (when debugging),
* it's useful if C-c is handled equivalent to SIGTERM. */
/* When journald is invoked on the terminal (when debugging), it's useful if C-c is handled
* equivalent to SIGTERM. */
r = sd_event_add_signal(s->event, &s->sigint_event_source, SIGINT, dispatch_sigterm, s);
if (r < 0)
return r;
@ -1437,11 +1436,9 @@ static int setup_signals(Server *s) {
if (r < 0)
return r;
/* SIGRTMIN+1 causes an immediate sync. We process this very
* late, so that everything else queued at this point is
* really written to disk. Clients can watch
* /run/systemd/journal/synced with inotify until its mtime
* changes to see when a sync happened. */
/* SIGRTMIN+1 causes an immediate sync. We process this very late, so that everything else queued at
* this point is really written to disk. Clients can watch /run/systemd/journal/synced with inotify
* until its mtime changes to see when a sync happened. */
r = sd_event_add_signal(s->event, &s->sigrtmin1_event_source, SIGRTMIN+1, dispatch_sigrtmin1, s);
if (r < 0)
return r;
@ -1759,23 +1756,17 @@ static int server_connect_notify(Server *s) {
assert(!s->notify_event_source);
/*
So here's the problem: we'd like to send notification
messages to PID 1, but we cannot do that via sd_notify(),
since that's synchronous, and we might end up blocking on
it. Specifically: given that PID 1 might block on
dbus-daemon during IPC, and dbus-daemon is logging to us,
and might hence block on us, we might end up in a deadlock
if we block on sending PID 1 notification messages — by
generating a full blocking circle. To avoid this, let's
create a non-blocking socket, and connect it to the
notification socket, and then wait for POLLOUT before we
send anything. This should efficiently avoid any deadlocks,
as we'll never block on PID 1, hence PID 1 can safely block
on dbus-daemon which can safely block on us again.
Don't think that this issue is real? It is, see:
https://github.com/systemd/systemd/issues/1505
*/
* So here's the problem: we'd like to send notification messages to PID 1, but we cannot do that via
* sd_notify(), since that's synchronous, and we might end up blocking on it. Specifically: given
* that PID 1 might block on dbus-daemon during IPC, and dbus-daemon is logging to us, and might
* hence block on us, we might end up in a deadlock if we block on sending PID 1 notification
* messages — by generating a full blocking circle. To avoid this, let's create a non-blocking
* socket, and connect it to the notification socket, and then wait for POLLOUT before we send
* anything. This should efficiently avoid any deadlocks, as we'll never block on PID 1, hence PID 1
* can safely block on dbus-daemon which can safely block on us again.
*
* Don't think that this issue is real? It is, see: https://github.com/systemd/systemd/issues/1505
*/
e = getenv("NOTIFY_SOCKET");
if (!e)
@ -1807,8 +1798,7 @@ static int server_connect_notify(Server *s) {
return log_error_errno(r, "Failed to add watchdog time event: %m");
}
/* This should fire pretty soon, which we'll use to send the
* READY=1 event. */
/* This should fire pretty soon, which we'll use to send the READY=1 event. */
return 0;
}