hello
i think i'll do the checkexit() and doublecheck again all exiting procs unlocks
all the locks they had, as the only place to check is when a proc is waiting to
read from the 9p pipe:
qlock(&iorlock);
n = read9pmsg(mfd[0], io->mdata, messagesize);
qunlock(&iorlock);
thanks!
gabi
>> I have a couple of processes working together sharing memory and using
>> locks, and when the program finish the job and exits, the proceses in Rendez
>> state does not exit, and i need to slay them.
>>
>> I'm using postnote(PNGROUP,...) call, should i write a postctl to slay the
>> waiting proceses or is there a better way to accomplish this? (may be using
>> canlock and wait for it with a loop and sleep instead of a qlock?)
>
> looping on canq?lock is not a good idea.
>
> i think what you want is to ensure that no proc is
> doing anything that shouldn't be interrupted when
> it is killed or quits. for many programs, interrupting
> writes is a bad idea. one would want a half-written
> upas index file, for instance. rc checks a global sentinal at
> a few strategic points (where it can clean up easily)
> when it receives a signal. perhaps you could borrow
> this technique, as in
>
> /*
> * exit the building single file
> */
> void
> chkexit(QLock *q)
> {
> if(!exiting)
> return;
> qunlock(q)
> cleanexit();
> }
> ...
> qlock(&resourcelk);
> chkexit(&resourcelk);
> ...
> qunlock(&resourcelk);
>
> this might not be appropriate. the bad things
> that might happen if your interrupted in the
> middle of something might not be bad enough
> to worry about or this might be difficult to implement
> with your program.
>
> - erik
