Use a non-blocking syslog socket if logging from PID 1.
If sendmsg fails with EAGAIN, fall back to kmsg or console only for the
current message. Next message will try syslog again.
Chen Jie observed and analyzed a deadlock. Assuming systemd-kmsg-syslogd
is already stopped, but rsyslogd is not started yet:
1. systemd makes a synchronous call to dbus-daemon.
2. dbus-daemon wants to write something to syslog.
3. syslog needs to be started by systemd.
... but cannot be, because systemd is waiting in 1.
Solve this by avoiding synchronous D-Bus calls. I had to write an async
bus registration call. Interestingly, D-Bus authors anticipated this, in
documentation to dbus_bus_set_unique_name():
> The only reason to use this function is to re-implement the equivalent
> of dbus_bus_register() yourself. One (probably unusual) reason to do
> that might be to do the bus registration call asynchronously instead
> of synchronously.
Lennart's comments from IRC:
> though I think this doesn't fix the problem in its entirety
> simply because dbus_connection_open_private() itself is still synchronous
> i.e. the connect() call behind it is not async
> I think I listed that issue actually on some D-Bus todo list
> i.e. to make dbus_connection_get() fully async
> but that's going to be hard
> so your patch looks good
So it may not be perfect, but it's clearly an improvement.
I did not manage to reproduce the original deadlock with the patch.
A freshly started unit A was immediately considered unneeded just because
unit B, which Requires A, was starting later in the transaction.
Fix it by looking not only at the state of B, but also at its pending job.
Also fix a copied&pasted comment.
Be consistent in coloring of load states in list-units and status.
Print only 'error' in red.
There are no 'banned' or 'failed' states. Do not color 'masked', it's
not an error.
Units that failed to load were never cleaned up. It was possible to
reach the 128K limit of units by attempting to load a bunch of nonsense.
Bug observed by Reartes Guillermo in
https://bugzilla.redhat.com/show_bug.cgi?id=680122
To do so, move the check for the bus to the bus-using portion of
list_unit_files(), and ensure that get_config_path doesn't abort when
checking the runtime path with --root.
Ville Skyttä
Lennart Poettering
Michal Schmidt
Dan Walsh
Gregs Gregs
Kay Sievers
Tim Waugh
Bill Nottingham