/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <thread.h>#include "threadimpl.h" enum{	STACK = 8192,}; voidiointerrupt(Ioproc *io){	if(!io->inuse)		return;	threadint(io->tid);} static voidxioproc(void *a){	Ioproc *io, *x;	io = a;	/*	 * first recvp acquires the ioproc.	 * second tells us that the data is ready.	 */	for(;;){		while(recv(io->c, &x) == -1)			;		if(x == 0)	/* our cue to leave */			break;		assert(x == io); 		/* caller is now committed -- even if interrupted he'll return */		while(recv(io->creply, &x) == -1)			;		if(x == 0)	/* caller backed out */			continue;		assert(x == io); 		io->ret = io->op(&io->arg);		if(io->ret < 0)			rerrstr(io->err, sizeof io->err);		while(send(io->creply, &io) == -1)			;		while(recv(io->creply, &x) == -1)			;	}} Ioproc*ioproc(void){	Ioproc *io; 	io = mallocz(sizeof(*io), 1);	if(io == nil)		sysfatal("ioproc malloc: %r");	io->c = chancreate(sizeof(void*), 0);	io->creply = chancreate(sizeof(void*), 0);	io->tid = proccreate(xioproc, io, STACK);	return io;} voidcloseioproc(Ioproc *io){	if(io == nil)		return;	iointerrupt(io);	while(send(io->c, 0) == -1)		;	chanfree(io->c);	chanfree(io->creply);	free(io);}