svn commit: r229667 - head/usr.sbin/daemon

[Doug Barton]

On 01/24/2012 07:34, Guy Helmer wrote:
> On Jan 6, 2012, at 6:16 PM, Doug Barton wrote:
> 
>> On 01/06/2012 08:18, Guy Helmer wrote:
>>> On Jan 5, 2012, at 8:58 PM, Doug Barton wrote:
>>>
>>>> On 01/05/2012 14:48, Guy Helmer wrote:
>>>>> Allow daemon(8) to run pidfile_open() before relenquishing
>>>>> privileges so pid files can be written in /var/run when started
>>>>> as root.
>>>>
>>>> I'm not sure how useful this is since when daemon is exiting it
>>>> won't be able to remove the pid file (unless I'm missing
>>>> something).
>>>>
>>>> Isn't it better to pre-create the pid file with the proper
>>>> permissions for the unprivileged user?
>>>>
>>>
>>> Would it be OK for daemon to hang around and wait for the child
>>> process to exit, then remove the pid file?
>>
>> Without having given it any kind of careful thought, that sounds Ok ...
>> but I don't understand how daemon could remove a pid file written as
>> root after it's already dropped privileges. (IOW that's the same problem
>> I was bringing up.)
>>
>>> The only other alternative I see would be to create a subdirectory
>>> that is writable by the user so the child can create and delete the
>>> pid file.
>>
>> That's functionally equivalent to pre-creating the pid file with the
>> right permissions, so it would be Ok. Various ports use each of these
>> approaches. I'm generally in favor of using the pid file only solution
>> since rc.d/cleanvar will clean all that stuff up at boot, and it's
>> preferable to not leave stale directories around for stuff that is no
>> longer running and/or installed.
> 
> Having thought about it for a while, I plan to revert the change to daemon.c that was suggested in the PR, and instead add this note to the man page:

I think that reverting it is a good idea. I would add something to the
effect of what's below. I continue to maintain that pre-creating the
file is preferable to using directories since we'd like to avoid leaving
no-longer-relevant directories around if the thing is not in use any
longer.


Doug


> Index: daemon.8
> ===================================================================
> --- daemon.8	(revision 230510)
> +++ daemon.8	(working copy)
> @@ -59,6 +59,10 @@
>  using the
>  .Xr pidfile 3
>  functionality.
> +If the
> +.Fl u
> +option is used the pidfile must be pre-created with the proper
> +permissions, or the directory to contain the pidfile must be writable
> +by the specified user.
>  Note, that the file will be created shortly before the process is
>  actually executed, and will remain after the process exits (although
>  it will be removed if the execution fails).
> 
> Guy
> 
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