add logic for master to write a pidfile

[bahamas10]

notes

I tried to place the logic in bud.c right above the call to uv_run but the ended up confused as to why there are 2 calls to uv_run... either way i've tested this and it seems to work as expected.

[indutny]

unlink().

[indutny]

Thank you very much for your contribution! Could you please fix some nits?

[bahamas10]

definitely... i'll make the changes!

one question though: I was originally going to use open/write/close instead of fopen/fprintf/fclose, but I see based on the source code bud supports Windows. I thought the f* functions were meant to create a higher level abstraction for open/write/close on non-unixy systems? I could be wrong, as I've never done any Windows programming, but will open/write/close work as expected for Windows?

either way, I much prefer just using the syscalls directly... it's easier and simpler.

[indutny]

Hm... I just thought that we could try using synchronous libuv API for this purpose :) Would you mind investigating this?

Also, is it happening in a right place right now? From what I see it seems that the worker's could overwrite master's pid file...

[bahamas10]

I agree, the libuv API is probably the safest bet for cross-platfrom compatibility... i can figure that out... it's time i dug into libuv anyway :)

As far as I can tell, only the master will write the pid because of this check

if (!config->is_worker && config->pidfile != NULL) {
  // make pid file
}

[indutny]

Ah, I see... Why not move this code to master.c then?