#include <u.h>#include <libc.h>#include <thread.h>#include "threadimpl.h" enum{	STACK = 8192,}; voidiointerrupt(Ioproc *io){	if(io->ctl < 0)		return;	qlock(io);	if(++io->intr == 1)		write(io->ctl, "interrupt", 9);	qunlock(io);} static intopenprocctl(void){	char buf[32]; 	snprint(buf, sizeof(buf), "/proc/%lud/ctl", (ulong)getpid());	return open(buf, OWRITE|OCEXEC);} static voidxioproc(void *a){	Channel *c;	Ioproc *io;	Iocall *r; 	c = a;	if(io = mallocz(sizeof(*io), 1)){		/*		 * open might fail, ignore it for programs like factotum		 * that don't use iointerrupt() anyway.		 */		io->ctl = openprocctl();		if((io->creply = chancreate(sizeof(void*), 0)) == nil){			if(io->ctl >= 0)				close(io->ctl);			free(io);			io = nil;		} else			io->c = c;	}	while(send(c, &io) < 0)		;	if(io == nil)		return; 	for(;;){		while(recv(io->c, &r) < 0)			;		if(r == 0)			break;		if(io->intr){			r->ret = -1;			strcpy(r->err, "interrupted");		} else if((r->ret = r->op(&r->arg)) < 0)			rerrstr(r->err, sizeof r->err);		qlock(io);		if(io->intr){			io->intr = 0;			if(io->ctl >= 0)				write(io->ctl, "nointerrupt", 11);		}		while(send(io->creply, &r) < 0)			;		qunlock(io);	} 	if(io->ctl >= 0)		close(io->ctl);	chanfree(io->c);	chanfree(io->creply);	free(io);} Ioproc*ioproc(void){	Channel *c;	Ioproc *io; 	if((c = chancreate(sizeof(void*), 0)) == nil)		sysfatal("ioproc chancreate");	proccreate(xioproc, c, STACK);	while(recv(c, &io) < 0)		;	if(io == nil)		sysfatal("ioproc alloc");	return io;} voidcloseioproc(Ioproc *io){	if(io == nil)		return;	iointerrupt(io);	while(sendp(io->c, nil) < 0)		;}