To start GNUspool, spshed should be started. This should normally be done using gspl-start(1), which restarts it and passes the appropriate options. This may be put within the Operating System startup scripts.
Likewise to halt it, gspl-stop(1) should be invoked. This should be put, using the -y option, in any system shutdown routines.
If you do need to kill spshed for any reason, first try kill(1) without any -9 option. This will give spshed the opportunity to attempt to tidy up any IPC facilities before shutting down.
Information, either in respect of other machines to connect to, or pre-existing jobs and printers on the current machine, are read from the files gnuspool.hosts and the spool directory respectively.
If a networked version of GNUspool is being run, then a ``slave'' spshed process is spawned to monitor and process incoming network messages. Incoming remotely-submitted jobs and API interfaces are handled via a separate process xtnetserv(8), which is also invoked as appropriate by gspl-start(1).
Appropriate log messages are written by spshed and other system processes to a log file, spshed_reps. Be sure to check this file for any error messages relevant to any problems you encounter.
gnuspool.conf master configuration file
int-config message file
spshed_jfile job file
spshed_pfile printer file
spshed_reps error log file
spufile0 user data
charges0 user charges data
spmm_jobi job memory-mapped hash file
spmm_jobd job memory-mapped data file
spmm_ptrs printers memory-mapped file
spmm_xfer communication buffer memory-mapped file
Two shared memory segments are created to hold details of jobs and printers. As the shared memory facility provides no facilities for growth, then additional shared memory segments may be created if the job and printer lists expand sufficiently and the original ones deallocated.
The keys given to the shared memory segments start at 0x58691002 and ascend upwards to 0x58691064 before wrapping around.
A further shared memory segment, with key 0x58692002 is created to hold details of pending jobs before transfer to the main shared memory segment.
Versions of spshed may use memory-mapped files rather than shared memory. The files are held in the spool directory, by default /var/spool/gnuspool, and have the names spmm_jobi, spmm_jobd, spmm_ptrs and spmm_xfer.
A set of 5 semaphores, with the key 0x58691001 is created to interlock access to the shared memory segments.
The presence or absence of these IPC facilities is used by spshed and other programs to determine whether a previous copy of itself is running. If spshed is abnormally terminated, it will probably be necessary to delete these IPC facilities before spshed can be restarted.
When printers are set running, spshed invokes an instance of spd(8) to control each printer. Mail and attention messages are passed to spmdisp(8) for processing.
The port numbers are set up in the /etc/services file when GNUspool is first installed.
In the event of any problems this file should be examined.