Re: [9fans] protection against resource exhaustion

[arisawa <arisawa@ar.aichi-u.ac.jp>]

Thanks for all.

I have looked old source code /sys/src/9/port/proc.c, and found the next code exists from very old day.

	lock(&procalloc);
	for(;;) {
		if((p = procalloc.free) != nil)
			break;

		snprint(msg, sizeof msg, "no procs; %s forking",
			up != nil ? up->text: "kernel");
		unlock(&procalloc);
		resrcwait(msg);
		lock(&procalloc);
	}
	procalloc.free = p->qnext;
	unlock(&procalloc);

and rfork(2) says:
	Rfork will sleep, if necessary, until required process resources are available.
which is also exists from old day.

Nevertheless all programs, I believe, in /sys/src are written assuming rfork() may return -l:
	switch(rfork(….)){
	case -1:
	  …
	}

Any merit?