static void
getaddr(char *path, uint8_t *ea)
{
	Proc *up = externup();
	char buf[6*2];
	int n;
	Chan *c;

	snprint(up->genbuf, sizeof up->genbuf, "%s/addr", path);
	c = namec(up->genbuf, Aopen, OREAD, 0);
	if(waserror()) {
		cclose(c);
		nexterror();
	}
	n = c->dev->read(c, buf, sizeof buf, 0);
	if(n != sizeof buf)
		error("getaddr");
	if(parseether(ea, buf) < 0)
		error("parseether failure");
	poperror();
	cclose(c);
}

static int32_t
srvwrite(Chan *c, void *va, int32_t n, int64_t mm)
{
	Proc *up = externup();
	Srv *sp;
	Chan *c1;
	int fd;
	char buf[32];

	if(n >= sizeof buf)
		error(Egreg);
	memmove(buf, va, n);	/* so we can NUL-terminate */
	buf[n] = 0;
	fd = strtoul(buf, 0, 0);

	c1 = fdtochan(fd, -1, 0, 1);	/* error check and inc ref */

	qlock(&srvlk);
	if(waserror()) {
		qunlock(&srvlk);
		cclose(c1);
		nexterror();
	}
	if(c1->flag & (CCEXEC|CRCLOSE))
		error("posted fd has remove-on-close or close-on-exec");
	if(c1->qid.type & QTAUTH)
		error("cannot post auth file in srv");
	sp = srvlookup(nil, c->qid.path);
	if(sp == 0)
		error(Enonexist);

	if(sp->chan)
		error(Ebadusefd);

	sp->chan = c1;
	qunlock(&srvlk);
	poperror();
	return n;
}

void
init0(void)
{
	int i;
	char buf[2*KNAMELEN];

	up->nerrlab = 0;

	spllo();

	/*
	 * These are o.k. because rootinit is null.
	 * Then early kproc's will have a root and dot.
	 */
	up->slash = namec("#/", Atodir, 0, 0);
	pathclose(up->slash->path);
	up->slash->path = newpath("/");
	up->dot = cclone(up->slash);

	chandevinit();

	if(!waserror()){
		snprint(buf, sizeof(buf), "%s %s", arch->id, conffile);
		ksetenv("terminal", buf, 0);
		ksetenv("cputype", "386", 0);
		if(cpuserver)
			ksetenv("service", "cpu", 0);
		else
			ksetenv("service", "terminal", 0);
		for(i = 0; i < nconf; i++){
			if(confname[i][0] != '*')
				ksetenv(confname[i], confval[i], 0);
			ksetenv(confname[i], confval[i], 1);
		}
		poperror();
	}
	kproc("alarm", alarmkproc, 0);
	touser(sp);
}

static int
srvwstat(Chan *c, uchar *dp, int n)
{
	Dir *d;
	SrvFile *sf, *f;

	sf = c->aux;
	if(strcmp(up->env->user, sf->user) != 0)
		error(Eperm);

	d = smalloc(sizeof(*d)+n);
	if(waserror()){
		free(d);
		nexterror();
	}
	n = convM2D(dp, n, d, (char*)&d[1]);
	if(n == 0)
		error(Eshortstat);
	if(!emptystr(d->name)){
		if(sf->dir == nil)
			error(Eperm);
		validwstatname(d->name);
		qlock(&dev.l);
		for(f = sf->dir; f != nil; f = f->entry)
			if(strcmp(f->name, d->name) == 0){
				qunlock(&dev.l);
				error(Eexist);
			}
		kstrdup(&sf->name, d->name);
		qunlock(&dev.l);
	}
	if(d->mode != ~0UL)
		sf->perm = d->mode & (DMEXCL|DMAPPEND|0777);
	if(d->length != (vlong)-1)
		sf->length = d->length;
	poperror();
	free(d);
	return n;
}

static Chan*
srvopen(Chan *c, int omode)
{
	SrvFile *sf;

	openmode(omode);	/* check it */
	if(c->qid.type & QTDIR){
		if(omode != OREAD)
			error(Eisdir);
		c->mode = omode;
		c->flag |= COPEN;
		c->offset = 0;
		return c;
	}

	sf = c->aux;

	qlock(&dev.l);
	if(waserror()){
		qunlock(&dev.l);
		nexterror();
	}
	devpermcheck(sf->user, sf->perm, omode);
	if(omode&ORCLOSE && strcmp(sf->user, up->env->user) != 0)
		error(Eperm);
	if(sf->perm & DMEXCL && sf->opens != 0)
		error(Einuse);
	sf->opens++;
	if(omode&ORCLOSE)
		sf->flags |= SORCLOSE;
	poperror();
	qunlock(&dev.l);

	c->offset = 0;
	c->flag |= COPEN;
	c->mode = openmode(omode);

	return c;
}

int
pwait(Waitmsg *w)
{
	int cpid;
	Waitq *wq;

	if(!canqlock(&up->qwaitr))
		error(Einuse);

	if(waserror()) {
		qunlock(&up->qwaitr);
		nexterror();
	}

	lock(&up->exl);
	if(up->nchild == 0 && up->waitq == 0) {
		unlock(&up->exl);
		error(Enochild);
	}
	unlock(&up->exl);

	sleep(&up->waitr, haswaitq, up);

	lock(&up->exl);
	wq = up->waitq;
	up->waitq = wq->next;
	up->nwait--;
	unlock(&up->exl);

	qunlock(&up->qwaitr);
	poperror();

	if(w)
		memmove(w, &wq->w, sizeof(Waitmsg));
	cpid = wq->w.pid;
	free(wq);

	return cpid;
}

/*
 * Return a copy of configuration environment as a sequence of strings.
 * The strings alternate between name and value.  A zero length name string
 * indicates the end of the list
 */
char *
getconfenv(void)
{
	Egrp *eg = &confegrp;
	Evalue *e;
	char *p, *q;
	int i, n;

	rlock(eg);
	if(waserror()) {
		runlock(eg);
		nexterror();
	}
	
	/* determine size */
	n = 0;
	for(i=0; i<eg->nent; i++){
		e = eg->ent[i];
		n += strlen(e->name) + e->len + 2;
	}
	p = malloc(n + 1);
	if(p == nil)
		error(Enomem);
	q = p;
	for(i=0; i<eg->nent; i++){
		e = eg->ent[i];
		strcpy(q, e->name);
		q += strlen(q) + 1;
		memmove(q, e->value, e->len);
		q[e->len] = 0;
		/* move up to the first null */
		q += strlen(q) + 1;
	}
	*q = '\0';
	
	poperror();
	runlock(eg);
	return p;
}

static Chan*
srvopen(Chan *c, int omode)
{
	Proc *up = externup();
	Srv *sp;

	if(c->qid.type == QTDIR){
		if(omode & ORCLOSE)
			error(Eperm);
		if(omode != OREAD)
			error(Eisdir);
		c->mode = omode;
		c->flag |= COPEN;
		c->offset = 0;
		return c;
	}
	qlock(&srvlk);
	if(waserror()){
		qunlock(&srvlk);
		nexterror();
	}

	sp = srvlookup(nil, c->qid.path);
	if(sp == 0 || sp->chan == 0)
		error(Eshutdown);

	if(omode&OTRUNC)
		error("srv file already exists");
	if(openmode(omode)!=sp->chan->mode && sp->chan->mode!=ORDWR)
		error(Eperm);
	devpermcheck(sp->owner, sp->perm, omode);

	cclose(c);
	incref(sp->chan);
	qunlock(&srvlk);
	poperror();
	return sp->chan;
}

long
cswrite(Chan *c, void *a, long n, vlong offset)
{
	char *f[4];
	char *s, *ns;
	ulong ip;
	int nf, port;

	s = malloc(n+1);
	if(s == nil)
		error(Enomem);
	if(waserror()){
		free(s);
		nexterror();
	}
	memmove(s, a, n);
	s[n] = 0;
	nf = getfields(s, f, nelem(f), 0, "!");
	if(nf != 3)
		error("can't translate");

	port = lookupport(f[2]);
	if(port <= 0)
		error("no translation for port found");

	ip = lookuphost(f[1]);
	if(ip == 0)
		error("no translation for host found");

	ns = smprint("/net/%s/clone %I!%d", f[0], ip, port);
	if(ns == nil)
		error(Enomem);
	free(c->aux);
	c->aux = ns;
	poperror();
	free(s);
	return n;
}

long
syspipe(uint32 *arg)
{
	int fd[2];
	Chan *c[2];
	Dev *d;
	static char *datastr[] = {"data", "data1"};
	int *ufd;
	
	ufd = uvalidaddr(arg[0], 2*BY2WD, 1);
	evenaddr(arg[0]);
	d = devtab[devno('|', 0)];
	c[0] = namec("#|", Atodir, 0, 0);
	c[1] = 0;
	fd[0] = -1;
	fd[1] = -1;

	if(waserror()){
		cclose(c[0]);
		if(c[1])
			cclose(c[1]);
		nexterror();
	}
	c[1] = cclone(c[0]);
	if(walk(&c[0], datastr+0, 1, 1, nil) < 0)
		error(Egreg);
	if(walk(&c[1], datastr+1, 1, 1, nil) < 0)
		error(Egreg);
	c[0] = d->open(c[0], ORDWR);
	c[1] = d->open(c[1], ORDWR);
	if(newfd2(fd, c) < 0)
		error(Enofd);
	poperror();

	ufd[0] = fd[0];
	ufd[1] = fd[1];
	return 0;
}

int
pprint(char *fmt, ...)
{
	int n;
	Chan *c;
	Osenv *o;
	va_list arg;
	char buf[2*PRINTSIZE];

	n = sprint(buf, "%s %ld: ", up->text, up->pid);
	va_start(arg, fmt);
	n = vseprint(buf+n, buf+sizeof(buf), fmt, arg) - buf;
	va_end(arg);

	o = up->env;
	if(o->fgrp == 0) {
		print("%s", buf);
		return 0;
	}
	c = o->fgrp->fd[2];
	if(c==0 || (c->mode!=OWRITE && c->mode!=ORDWR)) {
		print("%s", buf);
		return 0;
	}

	if(waserror()) {
		print("%s", buf);
		return 0;
	}
	devtab[c->type]->write(c, buf, n, c->offset);
	poperror();

	lock(c);
	c->offset += n;
	unlock(c);

	return n;
}

long
ctl(Ether *e, void *p, long n)
{
	Cmdbuf *cb;
	Cmdtab *ct;
	Ctlr *ctlr = e->ctlr;
	Gbereg *reg = ctlr->reg;

	cb = parsecmd(p, n);
	if(waserror()) {
		free(cb);
		nexterror();
	}

	ct = lookupcmd(cb, ctlmsg, nelem(ctlmsg));
	switch(ct->index) {
	case CMjumbo:
		if(strcmp(cb->f[1], "on") == 0) {
			/* incoming packet queue doesn't expect jumbo frames */
			error("jumbo disabled");
			reg->psc0 = (reg->psc0 & ~PSC0mrumask) |
				PSC0mru(PSC0mru9022);
			e->maxmtu = 9022;
		} else if(strcmp(cb->f[1], "off") == 0) {
			reg->psc0 = (reg->psc0 & ~PSC0mrumask) |
				PSC0mru(PSC0mru1522);
			e->maxmtu = ETHERMAXTU;
		} else
			error(Ebadctl);
		break;
	default:
		error(Ebadctl);
		break;
	}
	free(cb);
	poperror();
	return n;
}

static int
ipwstat(Chan *c, uchar *dp, int n)
{
	Dir *d;
	Conv *cv;
	Proto *p;
	Fs *f;

	f = ipfs[c->dev];
	switch(TYPE(c->qid)) {
	default:
		error(Eperm);
		break;
	case Qctl:
	case Qdata:
		break;
	}

	d = smalloc(sizeof(*d)+n);
	if(waserror()){
		free(d);
		nexterror();
	}
	n = convM2D(dp, n, d, (char*)&d[1]);
	if(n == 0)
		error(Eshortstat);
	p = f->p[PROTO(c->qid)];
	cv = p->conv[CONV(c->qid)];
	if(!iseve() && strcmp(up->env->user, cv->owner) != 0)
		error(Eperm);
	if(!emptystr(d->uid))
		kstrdup(&cv->owner, d->uid);
	if(d->mode != ~0UL)
		cv->perm = d->mode & 0777;
	poperror();
	free(d);
	return n;
}

static long
pipebwrite(Chan *c, Block *bp, ulong junk)
{
	long n;
	Pipe *p;

	USED(junk);
	if(waserror()) {
		/* avoid exceptions when pipe is a mounted queue */
		if((c->flag & CMSG) == 0) {
			if (up->ptype == Vm_proc) {
                vproc_t* r = (vproc_t*)up;
                if (r->kill == nil) {
                    r->kill = "write on closed pipe";
                }
            }
		}
		nexterror();
	}

	p = c->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;
}

static long
eventlogread(void *a, long n)
{
	int len;
	char *p, *buf;

	buf = smalloc(Eventlen);
	qlock(&events);
	lock(&events);
	p = events.rp;
	len = *p;
	if(len == 0){
		n = 0;
		unlock(&events);
	} else {
		if(n > len)
			n = len;
		/* can't move directly into pageable space with events lock held */
		memmove(buf, p+1, n);
		*p = 0;
		events.rp = p += Eventlen;
		if(p >= events.buf + sizeof events.buf)
			events.rp = events.buf;
		unlock(&events);

		/* the concern here is page faults in memmove below */
		if(waserror()){
			free(buf);
			qunlock(&events);
			nexterror();
		}
		memmove(a, buf, n);
		poperror();
	}
	free(buf);
	qunlock(&events);
	return n;
}

static char*
flushq(Ctlr *ctlr, uint qid)
{
	TXQ *q;
	int i;

	q = &ctlr->tx[qid];
	qlock(q);
	for(i = 0; i < 200 && !ctlr->broken; i++){
		if(txqempty(q)){
			qunlock(q);
			return nil;
		}
		if(islo() && !waserror()){
			tsleep(q, txqempty, q, 10);
			poperror();
		}
	}
	qunlock(q);
	if(ctlr->broken)
		return "flushq: broken";
	return "flushq: timeout";
}

static void
aoecfg(void)
{
	int n, i;
	char *p, *f[32], buf[24];

	if((p = getconf("aoeif")) == nil || (n = tokenize(p, f, nelem(f))) < 1)
		return;
	/* goo! */
	for(i = 0; i < n; i++){
		p = f[i];
		if(strncmp(p, "ether", 5) == 0)
			snprint(buf, sizeof buf, "#l%c/ether%c", p[5], p[5]);
		else if(strncmp(p, "#l", 2) == 0)
			snprint(buf, sizeof buf, "#l%c/ether%c", p[2], p[2]);
		else
			continue;
		if(!waserror()){
			netbind(buf);
			poperror();
		}
	}
}

static void
audioclose(Chan *c)
{
	Audiochan *ac;
	Audio *adev;

	ac = c->aux;
	adev = ac->adev;
	if((c->qid.path == Qaudio) && (c->flag & COPEN)){
		if(adev->close){
			if(!waserror()){
				adev->close(adev);
				poperror();
			}
		}
		decref(&adev->audioopen);
	}
	if(ac->owner == c){
		ac->owner = nil;
		c->aux = nil;
		free(ac);
	}
}

long
fsread(Chan *c, void *va, long n, vlong offset)
{
	int r;

	if(c->qid.type & QTDIR){	/* need to maintain offset only for directories */
		qlock(FS(c));
		if(waserror()){
			qunlock(FS(c));
			nexterror();
		}
		r = fsdirread(c, va, n, offset);
		poperror();
		qunlock(FS(c));
	}else{
		osenter();
		r = pread(FS(c)->fd, va, n, offset);
		osleave();
	}
	if(r < 0)
		fserr(FS(c));
	return r;
}

uintptr
syssegattach(va_list list)
{
	ulong attr;
	char *name;
	uintptr va;
	ulong len;

	attr = va_arg(list, ulong);
	name = va_arg(list, char*);
	va = va_arg(list, uintptr);
	len = va_arg(list, ulong);
	validaddr((uintptr)name, 1, 0);
	name = validnamedup(name, 1);
	if(waserror()){
		free(name);
		nexterror();
	}
	va = segattach(up, attr, name, va, len);
	free(name);
	poperror();
	return va;
}