** Description changed:
The apcupsd.service file in Ubuntu 20.04 LTS (amd64) includes the following
lines:
Type=forking
PIDFile=/var/run/apcupsd.pid
The systemd documentation
(https://www.freedesktop.org/software/systemd/man/systemd.service.html),
searching for "Type=forking", reports the following statement:
[...]
... if the process decides to write a traditional PID file, systemd will be
able to read the main PID from there. Please set PIDFile= accordingly. Note
that the daemon should write that file before finishing with its
initialization. Otherwise, systemd might try to read the file before it exists.
[...]
The issue is that, although the daemon is started and works correctly, the
"systemctl status apcupsd.service" call always reports the following:
systemd[1]: apcupsd.service: Can't open PID file /run/apcupsd.pid (yet?)
after start: Operation not permitted
This glitch is due to the fact that the parent process of the daemon exits
before the child has written the PID file.
- I proved this statement by recompiling apcupsd from source and inserting a
"sleep(1)" before the "exit(0) /* parent exits */" call in
apcupsd.c:daemon_start() function.
+ I proved this statement by recompiling apcupsd from source and inserting a
"sleep(1)" before the "exit(0) /* parent exits */" call in the daemon_start()
function (of apcupsd.c).
It fixed the issue by keeping the parent alive for a while, giving the child
enough time to call make_pid_file().
I know that sleep(1) is not a bugfix rather a test for verifying the
root cause of the issue.
I reported the issue to the apcupsd developers before filling this bug.
Anyway although their mailing list is alive and kicking, they do not
release a new version since 2016 so I am not so confident that they will
fix their source (at least not soon).
So could you please implement and apply a patch to the source that
delays the exit of the parent (i.e. waiting for the PID file of the
child to be created) in order to make apcupsd 100% compatible with
systemd?
** Description changed:
The apcupsd.service file in Ubuntu 20.04 LTS (amd64) includes the following
lines:
Type=forking
PIDFile=/var/run/apcupsd.pid
The systemd documentation
(https://www.freedesktop.org/software/systemd/man/systemd.service.html),
searching for "Type=forking", reports the following statement:
[...]
... if the process decides to write a traditional PID file, systemd will be
able to read the main PID from there. Please set PIDFile= accordingly. Note
that the daemon should write that file before finishing with its
initialization. Otherwise, systemd might try to read the file before it exists.
[...]
The issue is that, although the daemon is started and works correctly, the
"systemctl status apcupsd.service" call always reports the following:
systemd[1]: apcupsd.service: Can't open PID file /run/apcupsd.pid (yet?)
after start: Operation not permitted
This glitch is due to the fact that the parent process of the daemon exits
before the child has written the PID file.
I proved this statement by recompiling apcupsd from source and inserting a
"sleep(1)" before the "exit(0) /* parent exits */" call in the daemon_start()
function (of apcupsd.c).
It fixed the issue by keeping the parent alive for a while, giving the child
enough time to call make_pid_file().
I know that sleep(1) is not a bugfix rather a test for verifying the
root cause of the issue.
I reported the issue to the apcupsd developers before filling this bug.
Anyway although their mailing list is alive and kicking, they do not
release a new version since 2016 so I am not so confident that they will
fix their source (at least not soon).
So could you please implement and apply a patch to the source that
delays the exit of the parent (i.e. waiting for the PID file of the
- child to be created) in order to make apcupsd 100% compatible with
- systemd?
+ child to be created) in order to make apcupsd 100% compliant to what
+ systemd expects?
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https://bugs.launchpad.net/bugs/1967490
Title:
systemd: apcupsd daemon parent exits before the child creates the pid
file
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https://bugs.launchpad.net/ubuntu/+source/apcupsd/+bug/1967490/+subscriptions
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