#include "lib9.h"#include "sys.h"#include "error.h" enum {	Pipeqsize	= 32*1024}; typedef struct Pipe	Pipe;struct Pipe{	Qlock	lk;	Pipe	*next;	int	ref;	ulong	path;	Queue	*q[2];	int	qref[2];}; struct{	Lock	lk;	ulong	path;} pipealloc; enum{	Qdir,	Qdata0,	Qdata1}; static Dirtab pipedir[] ={	"data",		{Qdata0},	0,			0600,	"data1",	{Qdata1},	0,			0600,};#define NPIPEDIR 2 #define NETQID(i, t)	(((i)<<5)|(t))#define	NETTYPE(i)	((i)&0x1f)#define NETID(i)	(((i)&~CHDIR)>>5) voidpipeinit(void){} voidpipereset(void){} Chan*pipeattach(void *spec){	Pipe *p;	Chan *c; 	c = devattach('|', spec);	p = mallocz(sizeof(Pipe));	if(p == 0)		panic("memory");	p->ref = 1; 	p->q[0] = qopen(Pipeqsize, 0, 0, 0);	if(p->q[0] == 0){		free(p);		panic("memory");	}	p->q[1] = qopen(Pipeqsize, 0, 0, 0);	if(p->q[1] == 0){		free(p->q[0]);		free(p);		panic("memory");	} 	lock(&pipealloc.lk);	p->path = ++pipealloc.path;	unlock(&pipealloc.lk); 	c->qid.path = CHDIR|NETQID(2*p->path, Qdir);	c->qid.vers = 0;	c->u.aux = p;	c->dev = 0;	return c;} Chan*pipeclone(Chan *c, Chan *nc){	Pipe *p; 	p = c->u.aux;	nc = devclone(c, nc);	qlock(&p->lk);	p->ref++;	if(c->flag & COPEN){		switch(NETTYPE(c->qid.path)){		case Qdata0:			p->qref[0]++;			break;		case Qdata1:			p->qref[1]++;			break;		}	}	qunlock(&p->lk);	return nc;} intpipegen(Chan *c, Dirtab *tab, int ntab, int i, Dir *dp){	int id;	Qid q; 	id = NETID(c->qid.path);	if(i > 1)		id++;	if(tab==0 || i>=ntab)		return -1;	tab += i;	q.path = NETQID(id, tab->qid.path);	q.vers = 0;	devdir(c, q, tab->name, tab->length, eve, tab->perm, dp);	return 1;}  intpipewalk(Chan *c, char *name){	return devwalk(c, name, pipedir, NPIPEDIR, pipegen);} voidpipestat(Chan *c, char *db){	Pipe *p;	Dir dir; 	p = c->u.aux; 	switch(NETTYPE(c->qid.path)){	case Qdir:		devdir(c, c->qid, ".", 2*DIRLEN, eve, CHDIR|0555, &dir);		break;	case Qdata0:		devdir(c, c->qid, "data", qlen(p->q[0]), eve, 0660, &dir);		break;	case Qdata1:		devdir(c, c->qid, "data1", qlen(p->q[1]), eve, 0660, &dir);		break;	default:		panic("pipestat");	}	convD2M(&dir, db);} Chan *pipeopen(Chan *c, int omode){	Pipe *p; 	if(c->qid.path & CHDIR){		if(omode != OREAD)			error(Ebadarg);		c->mode = omode;		c->flag |= COPEN;		c->offset = 0;		return c;	} 	p = c->u.aux;	qlock(&p->lk);	switch(NETTYPE(c->qid.path)){	case Qdata0:		p->qref[0]++;		break;	case Qdata1:		p->qref[1]++;		break;	}	qunlock(&p->lk); 	c->mode = openmode(omode);	c->flag |= COPEN;	c->offset = 0;	return c;} voidpipecreate(Chan *c, char *name, int mode, ulong perm){	USED(c);	USED(name);	USED(mode);	USED(perm); 	error(Egreg);} voidpiperemove(Chan *c){	USED(c); 	error(Egreg);} voidpipewstat(Chan *c, char *buf){	USED(c);	USED(buf); 	error(Eperm);} voidpipeclose(Chan *c){	Pipe *p; 	p = c->u.aux;	qlock(&p->lk); 	if(c->flag & COPEN){		/*		 *  closing either side hangs up the stream		 */		switch(NETTYPE(c->qid.path)){		case Qdata0:			p->qref[0]--;			if(p->qref[0] == 0){				qhangup(p->q[1], 0);				qclose(p->q[0]);			}			break;		case Qdata1:			p->qref[1]--;			if(p->qref[1] == 0){				qhangup(p->q[0], 0);				qclose(p->q[1]);			}			break;		}	} 		/*	 *  if both sides are closed, they are reusable	 */	if(p->qref[0] == 0 && p->qref[1] == 0){		qreopen(p->q[0]);		qreopen(p->q[1]);	} 	/*	 *  free the structure on last close	 */	p->ref--;	if(p->ref == 0){		qunlock(&p->lk);		free(p->q[0]);		free(p->q[1]);		free(p);	} else		qunlock(&p->lk);} longpiperead(Chan *c, void *va, long n, ulong offset){	Pipe *p; 	USED(offset); 	p = c->u.aux; 	switch(NETTYPE(c->qid.path)){	case Qdir:		return devdirread(c, va, n, pipedir, NPIPEDIR, pipegen);	case Qdata0:		return qread(p->q[0], va, n);	case Qdata1:		return qread(p->q[1], va, n);	default:		panic("piperead");	}	return -1;	/* not reached */} Block*pipebread(Chan *c, long n, ulong offset){	Pipe *p; 	p = c->u.aux; 	switch(NETTYPE(c->qid.path)){	case Qdata0:		return qbread(p->q[0], n);	case Qdata1:		return qbread(p->q[1], n);	} 	return devbread(c, n, offset);} /* *  a write to a closed pipe causes a note to be sent to *  the process. */longpipewrite(Chan *c, void *va, long n, ulong offset){	Pipe *p; 	USED(offset); 	if(waserror())		error(Ehungup); 	p = c->u.aux; 	switch(NETTYPE(c->qid.path)){	case Qdata0:		n = qwrite(p->q[1], va, n);		break; 	case Qdata1:		n = qwrite(p->q[0], va, n);		break; 	default:		panic("pipewrite");	} 	poperror();	return n;} longpipebwrite(Chan *c, Block *bp, ulong offset){	long n;	Pipe *p; 	USED(offset); 	if(waserror())		error(Ehungup); 	p = c->u.aux;	switch(NETTYPE(c->qid.path)){	case Qdata0:		n = qbwrite(p->q[1], bp);		break; 	case Qdata1:		n = qbwrite(p->q[0], bp);		break; 	default:		n = 0;		panic("pipebwrite");	} 	poperror();	return n;}