[gpsd-dev] sequential startup and stale pid file

[Kiiski, Janne (EXT-Espotel - FI/Oulu)]

Hi,

Noticed that sequential startup of gpsd produces stale pid file.
Quick test (tested with current master, 
027002aff19ea428640d6e8489f4e992d95fc13b):

$ pgrep gpsd
$ gpsd -S 12345 -P $PWD/gpsd.pid /dev/ttyS0
$ pgrep gpsd
16161
$ cat gpsd.pid
16161
$ gpsd -S 12345 -P $PWD/gpsd.pid /dev/ttyS0
$ pgrep gpsd
16161
$ cat gpsd.pid
16165
$ kill $(cat gpsd.pid)
-bash: kill: (16165) - No such process

 From syslog:
Mar 13 09:41:56 jki gpsd[16165]: gpsd:ERROR: can't bind to IPv4 port 
12345, Address already in use
Mar 13 09:41:56 jki gpsd[16165]: gpsd:ERROR: maybe gpsd is already running!
Mar 13 09:41:56 jki gpsd[16165]: gpsd:ERROR: can't bind to IPv6 port 
12345, Address already in use
Mar 13 09:41:56 jki gpsd[16165]: gpsd:ERROR: maybe gpsd is already running!

Second process overwrites pid file -> fails to bind sockets -> exits == 
stale pid file.
So the pid file is (over)written too early (could/should be after 
successfull initialization, just before mainloop).

- janne kiiski