removing (outdated) drawterm

drawterm is much better maintained by russ cox,
so removing this outdated copy.

for a more recent version, go to:

http://swtch.com/drawterm/

1 files changed, 0 insertions, 1494 deletions

diff --git a/sys/src/cmd/unix/drawterm/kern/chan.c b/sys/src/cmd/unix/drawterm/kern/chan.c
deleted file mode 100644
index 7105f3a69..000000000
--- a/sys/src/cmd/unix/drawterm/kern/chan.c
+++ /dev/null
@@ -1,1494 +0,0 @@
-#include	"u.h"
-#include	"lib.h"
-#include	"dat.h"
-#include	"fns.h"
-#include	"error.h"
-
-int chandebug=0;		/* toggled by sysr1 */
-QLock chanprint;		/* probably asking for trouble (deadlocks) -rsc */
-
-int domount(Chan**, Mhead**);
-
-void
-dumpmount(void)		/* DEBUGGING */
-{
-	Pgrp *pg;
-	Mount *t;
-	Mhead **h, **he, *f;
-
-	if(up == nil){
-		print("no process for dumpmount\n");
-		return;
-	}
-	pg = up->pgrp;
-	if(pg == nil){
-		print("no pgrp for dumpmount\n");
-		return;
-	}
-	rlock(&pg->ns);
-	if(waserror()) {
-		runlock(&pg->ns);
-		nexterror();
-	}
-
-	he = &pg->mnthash[MNTHASH];
-	for(h = pg->mnthash; h < he; h++) {
-		for(f = *h; f; f = f->hash) {
-			print("head: %p: %s 0x%llux.%lud %C %lud -> \n", f,
-				f->from->name->s, f->from->qid.path,
-				f->from->qid.vers, devtab[f->from->type]->dc,
-				f->from->dev);
-			for(t = f->mount; t; t = t->next)
-				print("\t%p: %s (umh %p) (path %.8llux dev %C %lud)\n", t, t->to->name->s, t->to->umh, t->to->qid.path, devtab[t->to->type]->dc, t->to->dev);
-		}
-	}
-	poperror();
-	runlock(&pg->ns);
-}
-
-
-char*
-c2name(Chan *c)		/* DEBUGGING */
-{
-	if(c == nil)
-		return "<nil chan>";
-	if(c->name == nil)
-		return "<nil name>";
-	if(c->name->s == nil)
-		return "<nil name.s>";
-	return c->name->s;
-}
-
-enum
-{
-	CNAMESLOP	= 20
-};
-
-struct
-{
-	Lock lk;
-	int	fid;
-	Chan	*free;
-	Chan	*list;
-}chanalloc;
-
-typedef struct Elemlist Elemlist;
-
-struct Elemlist
-{
-	char	*name;	/* copy of name, so '/' can be overwritten */
-	int	nelems;
-	char	**elems;
-	int	*off;
-	int	mustbedir;
-};
-
-#define SEP(c) ((c) == 0 || (c) == '/')
-void cleancname(Cname*);
-
-int
-isdotdot(char *p)
-{
-	return p[0]=='.' && p[1]=='.' && p[2]=='\0';
-}
-
-int
-incref(Ref *r)
-{
-	int x;
-
-	lock(&r->lk);
-	x = ++r->ref;
-	unlock(&r->lk);
-	return x;
-}
-
-int
-decref(Ref *r)
-{
-	int x;
-
-	lock(&r->lk);
-	x = --r->ref;
-	unlock(&r->lk);
-	if(x < 0)
-		panic("decref, pc=0x%p", getcallerpc(&r));
-
-	return x;
-}
-
-/*
- * Rather than strncpy, which zeros the rest of the buffer, kstrcpy
- * truncates if necessary, always zero terminates, does not zero fill,
- * and puts ... at the end of the string if it's too long.  Usually used to
- * save a string in up->genbuf;
- */
-void
-kstrcpy(char *s, char *t, int ns)
-{
-	int nt;
-
-	nt = strlen(t);
-	if(nt+1 <= ns){
-		memmove(s, t, nt+1);
-		return;
-	}
-	/* too long */
-	if(ns < 4){
-		/* but very short! */
-		strncpy(s, t, ns);
-		return;
-	}
-	/* truncate with ... at character boundary (very rare case) */
-	memmove(s, t, ns-4);
-	ns -= 4;
-	s[ns] = '\0';
-	/* look for first byte of UTF-8 sequence by skipping continuation bytes */
-	while(ns>0 && (s[--ns]&0xC0)==0x80)
-		;
-	strcpy(s+ns, "...");
-}
-
-int
-emptystr(char *s)
-{
-	if(s == nil)
-		return 1;
-	if(s[0] == '\0')
-		return 1;
-	return 0;
-}
-
-/*
- * Atomically replace *p with copy of s
- */
-void
-kstrdup(char **p, char *s)
-{
-	int n;
-	char *t, *prev;
-
-	n = strlen(s)+1;
-	/* if it's a user, we can wait for memory; if not, something's very wrong */
-	if(up){
-		t = smalloc(n);
-		setmalloctag(t, getcallerpc(&p));
-	}else{
-		t = malloc(n);
-		if(t == nil)
-			panic("kstrdup: no memory");
-	}
-	memmove(t, s, n);
-	prev = *p;
-	*p = t;
-	free(prev);
-}
-
-void
-chandevreset(void)
-{
-	int i;
-
-	for(i=0; devtab[i] != nil; i++)
-		devtab[i]->reset();
-}
-
-void
-chandevinit(void)
-{
-	int i;
-
-	for(i=0; devtab[i] != nil; i++)
-		devtab[i]->init();
-}
-
-void
-chandevshutdown(void)
-{
-	int i;
-	
-	/* shutdown in reverse order */
-	for(i=0; devtab[i] != nil; i++)
-		;
-	for(i--; i >= 0; i--)
-		devtab[i]->shutdown();
-}
-
-Chan*
-newchan(void)
-{
-	Chan *c;
-
-	lock(&chanalloc.lk);
-	c = chanalloc.free;
-	if(c != 0)
-		chanalloc.free = c->next;
-	unlock(&chanalloc.lk);
-
-	if(c == nil) {
-		c = smalloc(sizeof(Chan));
-		lock(&chanalloc.lk);
-		c->fid = ++chanalloc.fid;
-		c->link = chanalloc.list;
-		chanalloc.list = c;
-		unlock(&chanalloc.lk);
-	}
-
-	/* if you get an error before associating with a dev,
-	   close calls rootclose, a nop */
-	c->type = 0;
-	c->flag = 0;
-	c->ref.ref = 1;
-	c->dev = 0;
-	c->offset = 0;
-	c->iounit = 0;
-	c->umh = 0;
-	c->uri = 0;
-	c->dri = 0;
-	c->aux = 0;
-	c->mchan = 0;
-	c->mcp = 0;
-	c->mux = 0;
-	memset(&c->mqid, 0, sizeof(c->mqid));
-	c->name = 0;
-	return c;
-}
-
-static Ref ncname;
-
-Cname*
-newcname(char *s)
-{
-	Cname *n;
-	int i;
-
-	n = smalloc(sizeof(Cname));
-	i = strlen(s);
-	n->len = i;
-	n->alen = i+CNAMESLOP;
-	n->s = smalloc(n->alen);
-	memmove(n->s, s, i+1);
-	n->ref.ref = 1;
-	incref(&ncname);
-	return n;
-}
-
-void
-cnameclose(Cname *n)
-{
-	if(n == nil)
-		return;
-	if(decref(&n->ref))
-		return;
-	decref(&ncname);
-	free(n->s);
-	free(n);
-}
-
-Cname*
-addelem(Cname *n, char *s)
-{
-	int i, a;
-	char *t;
-	Cname *new;
-
-	if(s[0]=='.' && s[1]=='\0')
-		return n;
-
-	if(n->ref.ref > 1){
-		/* copy on write */
-		new = newcname(n->s);
-		cnameclose(n);
-		n = new;
-	}
-
-	i = strlen(s);
-	if(n->len+1+i+1 > n->alen){
-		a = n->len+1+i+1 + CNAMESLOP;
-		t = smalloc(a);
-		memmove(t, n->s, n->len+1);
-		free(n->s);
-		n->s = t;
-		n->alen = a;
-	}
-	if(n->len>0 && n->s[n->len-1]!='/' && s[0]!='/')	/* don't insert extra slash if one is present */
-		n->s[n->len++] = '/';
-	memmove(n->s+n->len, s, i+1);
-	n->len += i;
-	if(isdotdot(s))
-		cleancname(n);
-	return n;
-}
-
-void
-chanfree(Chan *c)
-{
-	c->flag = CFREE;
-
-	if(c->umh != nil){
-		putmhead(c->umh);
-		c->umh = nil;
-	}
-	if(c->umc != nil){
-		cclose(c->umc);
-		c->umc = nil;
-	}
-	if(c->mux != nil){
-		muxclose(c->mux);
-		c->mux = nil;
-	}
-	if(c->mchan != nil){
-		cclose(c->mchan);
-		c->mchan = nil;
-	}
-
-	cnameclose(c->name);
-
-	lock(&chanalloc.lk);
-	c->next = chanalloc.free;
-	chanalloc.free = c;
-	unlock(&chanalloc.lk);
-}
-
-void
-cclose(Chan *c)
-{
-	if(c->flag&CFREE)
-		panic("cclose %p", getcallerpc(&c));
-
-	if(decref(&c->ref))
-		return;
-
-	if(!waserror()){
-		devtab[c->type]->close(c);
-		poperror();
-	}
-	chanfree(c);
-}
-
-/*
- * Make sure we have the only copy of c.  (Copy on write.)
- */
-Chan*
-cunique(Chan *c)
-{
-	Chan *nc;
-
-	if(c->ref.ref != 1) {
-		nc = cclone(c);
-		cclose(c);
-		c = nc;
-	}
-
-	return c;
-}
-
-int
-eqqid(Qid a, Qid b)
-{
-	return a.path==b.path && a.vers==b.vers;
-}
-
-int
-eqchan(Chan *a, Chan *b, int pathonly)
-{
-	if(a->qid.path != b->qid.path)
-		return 0;
-	if(!pathonly && a->qid.vers!=b->qid.vers)
-		return 0;
-	if(a->type != b->type)
-		return 0;
-	if(a->dev != b->dev)
-		return 0;
-	return 1;
-}
-
-int
-eqchantdqid(Chan *a, int type, int dev, Qid qid, int pathonly)
-{
-	if(a->qid.path != qid.path)
-		return 0;
-	if(!pathonly && a->qid.vers!=qid.vers)
-		return 0;
-	if(a->type != type)
-		return 0;
-	if(a->dev != dev)
-		return 0;
-	return 1;
-}
-
-Mhead*
-newmhead(Chan *from)
-{
-	Mhead *mh;
-
-	mh = smalloc(sizeof(Mhead));
-	mh->ref.ref = 1;
-	mh->from = from;
-	incref(&from->ref);
-
-/*
-	n = from->name->len;
-	if(n >= sizeof(mh->fromname))
-		n = sizeof(mh->fromname)-1;
-	memmove(mh->fromname, from->name->s, n);
-	mh->fromname[n] = 0;
-*/
-	return mh;
-}
-
-int
-cmount(Chan **newp, Chan *old, int flag, char *spec)
-{
-	Pgrp *pg;
-	int order, flg;
-	Mhead *m, **l, *mh;
-	Mount *nm, *f, *um, **h;
-	Chan *new;
-
-	if(QTDIR & (old->qid.type^(*newp)->qid.type))
-		error(Emount);
-
-if(old->umh)print("cmount old extra umh\n");
-
-	order = flag&MORDER;
-
-	if((old->qid.type&QTDIR)==0 && order != MREPL)
-		error(Emount);
-
-	new = *newp;
-	mh = new->umh;
-
-	/*
-	 * Not allowed to bind when the old directory
-	 * is itself a union.  (Maybe it should be allowed, but I don't see
-	 * what the semantics would be.)
-	 *
-	 * We need to check mh->mount->next to tell unions apart from
-	 * simple mount points, so that things like
-	 *	mount -c fd /root
-	 *	bind -c /root /
-	 * work.  The check of mount->mflag catches things like
-	 *	mount fd /root
-	 *	bind -c /root /
-	 * 
-	 * This is far more complicated than it should be, but I don't
-	 * see an easier way at the moment.		-rsc
-	 */
-	if((flag&MCREATE) && mh && mh->mount
-	&& (mh->mount->next || !(mh->mount->mflag&MCREATE)))
-		error(Emount);
-
-	pg = up->pgrp;
-	wlock(&pg->ns);
-
-	l = &MOUNTH(pg, old->qid);
-	for(m = *l; m; m = m->hash) {
-		if(eqchan(m->from, old, 1))
-			break;
-		l = &m->hash;
-	}
-
-	if(m == nil) {
-		/*
-		 *  nothing mounted here yet.  create a mount
-		 *  head and add to the hash table.
-		 */
-		m = newmhead(old);
-		*l = m;
-
-		/*
-		 *  if this is a union mount, add the old
-		 *  node to the mount chain.
-		 */
-		if(order != MREPL)
-			m->mount = newmount(m, old, 0, 0);
-	}
-	wlock(&m->lock);
-	if(waserror()){
-		wunlock(&m->lock);
-		nexterror();
-	}
-	wunlock(&pg->ns);
-
-	nm = newmount(m, new, flag, spec);
-	if(mh != nil && mh->mount != nil) {
-		/*
-		 *  copy a union when binding it onto a directory
-		 */
-		flg = order;
-		if(order == MREPL)
-			flg = MAFTER;
-		h = &nm->next;
-		um = mh->mount;
-		for(um = um->next; um; um = um->next) {
-			f = newmount(m, um->to, flg, um->spec);
-			*h = f;
-			h = &f->next;
-		}
-	}
-
-	if(m->mount && order == MREPL) {
-		mountfree(m->mount);
-		m->mount = 0;
-	}
-
-	if(flag & MCREATE)
-		nm->mflag |= MCREATE;
-
-	if(m->mount && order == MAFTER) {
-		for(f = m->mount; f->next; f = f->next)
-			;
-		f->next = nm;
-	}
-	else {
-		for(f = nm; f->next; f = f->next)
-			;
-		f->next = m->mount;
-		m->mount = nm;
-	}
-
-	wunlock(&m->lock);
-	poperror();
-	return nm->mountid;
-}
-
-void
-cunmount(Chan *mnt, Chan *mounted)
-{
-	Pgrp *pg;
-	Mhead *m, **l;
-	Mount *f, **p;
-
-	if(mnt->umh)	/* should not happen */
-		print("cunmount newp extra umh %p has %p\n", mnt, mnt->umh);
-
-	/*
-	 * It _can_ happen that mounted->umh is non-nil, 
-	 * because mounted is the result of namec(Aopen)
-	 * (see sysfile.c:/^sysunmount).
-	 * If we open a union directory, it will have a umh.
-	 * Although surprising, this is okay, since the
-	 * cclose will take care of freeing the umh.
-	 */
-
-	pg = up->pgrp;
-	wlock(&pg->ns);
-
-	l = &MOUNTH(pg, mnt->qid);
-	for(m = *l; m; m = m->hash) {
-		if(eqchan(m->from, mnt, 1))
-			break;
-		l = &m->hash;
-	}
-
-	if(m == 0) {
-		wunlock(&pg->ns);
-		error(Eunmount);
-	}
-
-	wlock(&m->lock);
-	if(mounted == 0) {
-		*l = m->hash;
-		wunlock(&pg->ns);
-		mountfree(m->mount);
-		m->mount = nil;
-		cclose(m->from);
-		wunlock(&m->lock);
-		putmhead(m);
-		return;
-	}
-
-	p = &m->mount;
-	for(f = *p; f; f = f->next) {
-		/* BUG: Needs to be 2 pass */
-		if(eqchan(f->to, mounted, 1) ||
-		  (f->to->mchan && eqchan(f->to->mchan, mounted, 1))) {
-			*p = f->next;
-			f->next = 0;
-			mountfree(f);
-			if(m->mount == nil) {
-				*l = m->hash;
-				cclose(m->from);
-				wunlock(&m->lock);
-				wunlock(&pg->ns);
-				putmhead(m);
-				return;
-			}
-			wunlock(&m->lock);
-			wunlock(&pg->ns);
-			return;
-		}
-		p = &f->next;
-	}
-	wunlock(&m->lock);
-	wunlock(&pg->ns);
-	error(Eunion);
-}
-
-Chan*
-cclone(Chan *c)
-{
-	Chan *nc;
-	Walkqid *wq;
-
-	wq = devtab[c->type]->walk(c, nil, nil, 0);
-	if(wq == nil)
-		error("clone failed");
-	nc = wq->clone;
-	free(wq);
-	nc->name = c->name;
-	if(c->name)
-		incref(&c->name->ref);
-	return nc;
-}
-
-int
-findmount(Chan **cp, Mhead **mp, int type, int dev, Qid qid)
-{
-	Pgrp *pg;
-	Mhead *m;
-
-	pg = up->pgrp;
-	rlock(&pg->ns);
-	for(m = MOUNTH(pg, qid); m; m = m->hash){
-		rlock(&m->lock);
-if(m->from == nil){
-	print("m %p m->from 0\n", m);
-	runlock(&m->lock);
-	continue;
-}
-		if(eqchantdqid(m->from, type, dev, qid, 1)) {
-			runlock(&pg->ns);
-			if(mp != nil){
-				incref(&m->ref);
-				if(*mp != nil)
-					putmhead(*mp);
-				*mp = m;
-			}
-			if(*cp != nil)
-				cclose(*cp);
-			incref(&m->mount->to->ref);
-			*cp = m->mount->to;
-			runlock(&m->lock);
-			return 1;
-		}
-		runlock(&m->lock);
-	}
-
-	runlock(&pg->ns);
-	return 0;
-}
-
-int
-domount(Chan **cp, Mhead **mp)
-{
-	return findmount(cp, mp, (*cp)->type, (*cp)->dev, (*cp)->qid);
-}
-
-Chan*
-undomount(Chan *c, Cname *name)
-{
-	Chan *nc;
-	Pgrp *pg;
-	Mount *t;
-	Mhead **h, **he, *f;
-
-	pg = up->pgrp;
-	rlock(&pg->ns);
-	if(waserror()) {
-		runlock(&pg->ns);
-		nexterror();
-	}
-
-	he = &pg->mnthash[MNTHASH];
-	for(h = pg->mnthash; h < he; h++) {
-		for(f = *h; f; f = f->hash) {
-			if(strcmp(f->from->name->s, name->s) != 0)
-				continue;
-			for(t = f->mount; t; t = t->next) {
-				if(eqchan(c, t->to, 1)) {
-					/*
-					 * We want to come out on the left hand side of the mount
-					 * point using the element of the union that we entered on.
-					 * To do this, find the element that has a from name of
-					 * c->name->s.
-					 */
-					if(strcmp(t->head->from->name->s, name->s) != 0)
-						continue;
-					nc = t->head->from;
-					incref(&nc->ref);
-					cclose(c);
-					c = nc;
-					break;
-				}
-			}
-		}
-	}
-	poperror();
-	runlock(&pg->ns);
-	return c;
-}
-
-/*
- * Either walks all the way or not at all.  No partial results in *cp.
- * *nerror is the number of names to display in an error message.
- */
-static char Edoesnotexist[] = "does not exist";
-int
-walk(Chan **cp, char **names, int nnames, int nomount, int *nerror)
-{
-	int dev, dotdot, i, n, nhave, ntry, type;
-	Chan *c, *nc;
-	Cname *cname;
-	Mount *f;
-	Mhead *mh, *nmh;
-	Walkqid *wq;
-
-	c = *cp;
-	incref(&c->ref);
-	cname = c->name;
-	incref(&cname->ref);
-	mh = nil;
-
-	/*
-	 * While we haven't gotten all the way down the path:
-	 *    1. step through a mount point, if any
-	 *    2. send a walk request for initial dotdot or initial prefix without dotdot
-	 *    3. move to the first mountpoint along the way.
-	 *    4. repeat.
-	 *
-	 * An invariant is that each time through the loop, c is on the undomount
-	 * side of the mount point, and c's name is cname.
-	 */
-	for(nhave=0; nhave<nnames; nhave+=n){
-		if((c->qid.type&QTDIR)==0){
-			if(nerror)
-				*nerror = nhave;
-			cnameclose(cname);
-			cclose(c);
-			strcpy(up->errstr, Enotdir);
-			if(mh != nil)
-{print("walk 1\n");
-				putmhead(mh);
-}
-			return -1;
-		}
-		ntry = nnames - nhave;
-		if(ntry > MAXWELEM)
-			ntry = MAXWELEM;
-		dotdot = 0;
-		for(i=0; i<ntry; i++){
-			if(isdotdot(names[nhave+i])){
-				if(i==0) {
-					dotdot = 1;
-					ntry = 1;
-				} else
-					ntry = i;
-				break;
-			}
-		}
-
-		if(!dotdot && !nomount)
-			domount(&c, &mh);
-
-		type = c->type;
-		dev = c->dev;
-
-		if((wq = devtab[type]->walk(c, nil, names+nhave, ntry)) == nil){
-			/* try a union mount, if any */
-			if(mh && !nomount){
-				/*
-				 * mh->mount == c, so start at mh->mount->next
-				 */
-				rlock(&mh->lock);
-				for(f = mh->mount->next; f; f = f->next)
-					if((wq = devtab[f->to->type]->walk(f->to, nil, names+nhave, ntry)) != nil)
-						break;
-				runlock(&mh->lock);
-				if(f != nil){
-					type = f->to->type;
-					dev = f->to->dev;
-				}
-			}
-			if(wq == nil){
-				cclose(c);
-				cnameclose(cname);
-				if(nerror)
-					*nerror = nhave+1;
-				if(mh != nil)
-					putmhead(mh);
-				return -1;
-			}
-		}
-
-		nmh = nil;
-		if(dotdot) {
-			assert(wq->nqid == 1);
-			assert(wq->clone != nil);
-
-			cname = addelem(cname, "..");
-			nc = undomount(wq->clone, cname);
-			n = 1;
-		} else {
-			nc = nil;
-			if(!nomount)
-				for(i=0; i<wq->nqid && i<ntry-1; i++)
-					if(findmount(&nc, &nmh, type, dev, wq->qid[i]))
-						break;
-			if(nc == nil){	/* no mount points along path */
-				if(wq->clone == nil){
-					cclose(c);
-					cnameclose(cname);
-					if(wq->nqid==0 || (wq->qid[wq->nqid-1].type&QTDIR)){
-						if(nerror)
-							*nerror = nhave+wq->nqid+1;
-						strcpy(up->errstr, Edoesnotexist);
-					}else{
-						if(nerror)
-							*nerror = nhave+wq->nqid;
-						strcpy(up->errstr, Enotdir);
-					}
-					free(wq);
-					if(mh != nil)
-						putmhead(mh);
-					return -1;
-				}
-				n = wq->nqid;
-				nc = wq->clone;
-			}else{		/* stopped early, at a mount point */
-				if(wq->clone != nil){
-					cclose(wq->clone);
-					wq->clone = nil;
-				}
-				n = i+1;
-			}
-			for(i=0; i<n; i++)
-				cname = addelem(cname, names[nhave+i]);
-		}
-		cclose(c);
-		c = nc;
-		putmhead(mh);
-		mh = nmh;
-		free(wq);
-	}
-
-	putmhead(mh);
-
-	c = cunique(c);
-
-	if(c->umh != nil){	//BUG
-		print("walk umh\n");
-		putmhead(c->umh);
-		c->umh = nil;
-	}
-
-	cnameclose(c->name);
-	c->name = cname;
-
-	cclose(*cp);
-	*cp = c;
-	if(nerror)
-		*nerror = 0;
-	return 0;
-}
-
-/*
- * c is a mounted non-creatable directory.  find a creatable one.
- */
-Chan*
-createdir(Chan *c, Mhead *m)
-{
-	Chan *nc;
-	Mount *f;
-
-	rlock(&m->lock);
-	if(waserror()) {
-		runlock(&m->lock);
-		nexterror();
-	}
-	for(f = m->mount; f; f = f->next) {
-		if(f->mflag&MCREATE) {
-			nc = cclone(f->to);
-			runlock(&m->lock);
-			poperror();
-			cclose(c);
-			return nc;
-		}
-	}
-	error(Enocreate);
-	return 0;
-}
-
-void
-saveregisters(void)
-{
-}
-
-/*
- * In place, rewrite name to compress multiple /, eliminate ., and process ..
- */
-void
-cleancname(Cname *n)
-{
-	char *p;
-
-	if(n->s[0] == '#'){
-		p = strchr(n->s, '/');
-		if(p == nil)
-			return;
-		cleanname(p);
-
-		/*
-		 * The correct name is #i rather than #i/,
-		 * but the correct name of #/ is #/.
-		 */
-		if(strcmp(p, "/")==0 && n->s[1] != '/')
-			*p = '\0';
-	}else
-		cleanname(n->s);
-	n->len = strlen(n->s);
-}
-
-static void
-growparse(Elemlist *e)
-{
-	char **new;
-	int *inew;
-	enum { Delta = 8 };
-
-	if(e->nelems % Delta == 0){
-		new = smalloc((e->nelems+Delta) * sizeof(char*));
-		memmove(new, e->elems, e->nelems*sizeof(char*));
-		free(e->elems);
-		e->elems = new;
-		inew = smalloc((e->nelems+Delta+1) * sizeof(int));
-		memmove(inew, e->off, e->nelems*sizeof(int));
-		free(e->off);
-		e->off = inew;
-	}
-}
-
-/*
- * The name is known to be valid.
- * Copy the name so slashes can be overwritten.
- * An empty string will set nelem=0.
- * A path ending in / or /. or /.//./ etc. will have
- * e.mustbedir = 1, so that we correctly
- * reject, e.g., "/adm/users/." when /adm/users is a file
- * rather than a directory.
- */
-static void
-parsename(char *name, Elemlist *e)
-{
-	char *slash;
-
-	kstrdup(&e->name, name);
-	name = e->name;
-	e->nelems = 0;
-	e->elems = nil;
-	e->off = smalloc(sizeof(int));
-	e->off[0] = skipslash(name) - name;
-	for(;;){
-		name = skipslash(name);
-		if(*name=='\0'){
-			e->mustbedir = 1;
-			break;
-		}
-		growparse(e);
-		e->elems[e->nelems++] = name;
-		slash = utfrune(name, '/');
-		if(slash == nil){
-			e->off[e->nelems] = name+strlen(name) - e->name;
-			e->mustbedir = 0;
-			break;
-		}
-		e->off[e->nelems] = slash - e->name;
-		*slash++ = '\0';
-		name = slash;
-	}
-}
-
-void*
-mymemrchr(void *va, int c, long n)
-{
-	uchar *a, *e;
-
-	a = va;
-	for(e=a+n-1; e>a; e--)
-		if(*e == c)
-			return e;
-	return nil;
-}
-
-/*
- * Turn a name into a channel.
- * &name[0] is known to be a valid address.  It may be a kernel address.
- *
- * Opening with amode Aopen, Acreate, or Aremove guarantees
- * that the result will be the only reference to that particular fid.
- * This is necessary since we might pass the result to
- * devtab[]->remove().
- *
- * Opening Atodir, Amount, or Aaccess does not guarantee this.
- *
- * Opening Aaccess can, under certain conditions, return a
- * correct Chan* but with an incorrect Cname attached.
- * Since the functions that open Aaccess (sysstat, syswstat, sys_stat)
- * do not use the Cname*, this avoids an unnecessary clone.
- */
-Chan*
-namec(char *aname, int amode, int omode, ulong perm)
-{
-	int n, prefix, len, t, nomount, npath;
-	Chan *c, *cnew;
-	Cname *cname;
-	Elemlist e;
-	Rune r;
-	Mhead *m;
-	char *createerr, tmperrbuf[ERRMAX];
-	char *name;
-
-	name = aname;
-	if(name[0] == '\0')
-		error("empty file name");
-	validname(name, 1);
-
-	/*
-	 * Find the starting off point (the current slash, the root of
-	 * a device tree, or the current dot) as well as the name to
-	 * evaluate starting there.
-	 */
-	nomount = 0;
-	switch(name[0]){
-	case '/':
-		c = up->slash;
-		incref(&c->ref);
-		break;
-	
-	case '#':
-		nomount = 1;
-		up->genbuf[0] = '\0';
-		n = 0;
-		while(*name!='\0' && (*name != '/' || n < 2)){
-			if(n >= sizeof(up->genbuf)-1)
-				error(Efilename);
-			up->genbuf[n++] = *name++;
-		}
-		up->genbuf[n] = '\0';
-		/*
-		 *  noattach is sandboxing.
-		 *
-		 *  the OK exceptions are:
-		 *	|  it only gives access to pipes you create
-		 *	d  this process's file descriptors
-		 *	e  this process's environment
-		 *  the iffy exceptions are:
-		 *	c  time and pid, but also cons and consctl
-		 *	p  control of your own processes (and unfortunately
-		 *	   any others left unprotected)
-		 */
-		n = chartorune(&r, up->genbuf+1)+1;
-		/* actually / is caught by parsing earlier */
-		if(utfrune("M", r))
-			error(Enoattach);
-		if(up->pgrp->noattach && utfrune("|decp", r)==nil)
-			error(Enoattach);
-		t = devno(r, 1);
-		if(t == -1)
-			error(Ebadsharp);
-		c = devtab[t]->attach(up->genbuf+n);
-		break;
-
-	default:
-		c = up->dot;
-		incref(&c->ref);
-		break;
-	}
-	prefix = name - aname;
-
-	e.name = nil;
-	e.elems = nil;
-	e.off = nil;
-	e.nelems = 0;
-	if(waserror()){
-		cclose(c);
-		free(e.name);
-		free(e.elems);
-		free(e.off);
-//dumpmount();
-		nexterror();
-	}
-
-	/*
-	 * Build a list of elements in the path.
-	 */
-	parsename(name, &e);
-
-	/*
-	 * On create, ....
-	 */
-	if(amode == Acreate){
-		/* perm must have DMDIR if last element is / or /. */
-		if(e.mustbedir && !(perm&DMDIR)){
-			npath = e.nelems;
-			strcpy(tmperrbuf, "create without DMDIR");
-			goto NameError;
-		}
-
-		/* don't try to walk the last path element just yet. */
-		if(e.nelems == 0)
-			error(Eexist);
-		e.nelems--;
-	}
-
-	if(walk(&c, e.elems, e.nelems, nomount, &npath) < 0){
-		if(npath < 0 || npath > e.nelems){
-			print("namec %s walk error npath=%d\n", aname, npath);
-			nexterror();
-		}
-		strcpy(tmperrbuf, up->errstr);
-	NameError:
-		len = prefix+e.off[npath];
-		if(len < ERRMAX/3 || (name=mymemrchr(aname, '/', len))==nil || name==aname)
-			snprint(up->genbuf, sizeof up->genbuf, "%.*s", len, aname);
-		else
-			snprint(up->genbuf, sizeof up->genbuf, "...%.*s", (int)(len-(name-aname)), name);
-		snprint(up->errstr, ERRMAX, "%#q %s", up->genbuf, tmperrbuf);
-		nexterror();
-	}
-
-	if(e.mustbedir && !(c->qid.type&QTDIR)){
-		npath = e.nelems;
-		strcpy(tmperrbuf, "not a directory");
-		goto NameError;
-	}
-
-	if(amode == Aopen && (omode&3) == OEXEC && (c->qid.type&QTDIR)){
-		npath = e.nelems;
-		error("cannot exec directory");
-	}
-
-	switch(amode){
-	case Aaccess:
-		if(!nomount)
-			domount(&c, nil);
-		break;
-
-	case Abind:
-		m = nil;
-		if(!nomount)
-			domount(&c, &m);
-		if(c->umh != nil)
-			putmhead(c->umh);
-		c->umh = m;
-		break;
-
-	case Aremove:
-	case Aopen:
-	Open:
-		/* save the name; domount might change c */
-		cname = c->name;
-		incref(&cname->ref);
-		m = nil;
-		if(!nomount)
-			domount(&c, &m);
-
-		/* our own copy to open or remove */
-		c = cunique(c);
-
-		/* now it's our copy anyway, we can put the name back */
-		cnameclose(c->name);
-		c->name = cname;
-
-		switch(amode){
-		case Aremove:
-			putmhead(m);
-			break;
-
-		case Aopen:
-		case Acreate:
-if(c->umh != nil){
-	print("cunique umh Open\n");
-	putmhead(c->umh);
-	c->umh = nil;
-}
-
-			/* only save the mount head if it's a multiple element union */
-			if(m && m->mount && m->mount->next)
-				c->umh = m;
-			else
-				putmhead(m);
-
-			/* save registers else error() in open has wrong value of c saved */
-			saveregisters();
-
-			if(omode == OEXEC)
-				c->flag &= ~CCACHE;
-
-			c = devtab[c->type]->open(c, omode&~OCEXEC);
-
-			if(omode & OCEXEC)
-				c->flag |= CCEXEC;
-			if(omode & ORCLOSE)
-				c->flag |= CRCLOSE;
-			break;
-		}
-		break;
-
-	case Atodir:
-		/*
-		 * Directories (e.g. for cd) are left before the mount point,
-		 * so one may mount on / or . and see the effect.
-		 */
-		if(!(c->qid.type & QTDIR))
-			error(Enotdir);
-		break;
-
-	case Amount:
-		/*
-		 * When mounting on an already mounted upon directory,
-		 * one wants subsequent mounts to be attached to the
-		 * original directory, not the replacement.  Don't domount.
-		 */
-		break;
-
-	case Acreate:
-		/*
-		 * We've already walked all but the last element.
-		 * If the last exists, try to open it OTRUNC.
-		 * If omode&OEXCL is set, just give up.
-		 */
-		e.nelems++;
-		if(walk(&c, e.elems+e.nelems-1, 1, nomount, nil) == 0){
-			if(omode&OEXCL)
-				error(Eexist);
-			omode |= OTRUNC;
-			goto Open;
-		}
-
-		/*
-		 * The semantics of the create(2) system call are that if the
-		 * file exists and can be written, it is to be opened with truncation.
-		 * On the other hand, the create(5) message fails if the file exists.
-		 * If we get two create(2) calls happening simultaneously, 
-		 * they might both get here and send create(5) messages, but only 
-		 * one of the messages will succeed.  To provide the expected create(2)
-		 * semantics, the call with the failed message needs to try the above
-		 * walk again, opening for truncation.  This correctly solves the 
-		 * create/create race, in the sense that any observable outcome can
-		 * be explained as one happening before the other.
-		 * The create/create race is quite common.  For example, it happens
-		 * when two rc subshells simultaneously update the same
-		 * environment variable.
-		 *
-		 * The implementation still admits a create/create/remove race:
-		 * (A) walk to file, fails
-		 * (B) walk to file, fails
-		 * (A) create file, succeeds, returns 
-		 * (B) create file, fails
-		 * (A) remove file, succeeds, returns
-		 * (B) walk to file, return failure.
-		 *
-		 * This is hardly as common as the create/create race, and is really
-		 * not too much worse than what might happen if (B) got a hold of a
-		 * file descriptor and then the file was removed -- either way (B) can't do
-		 * anything with the result of the create call.  So we don't care about this race.
-		 *
-		 * Applications that care about more fine-grained decision of the races
-		 * can use the OEXCL flag to get at the underlying create(5) semantics;
-		 * by default we provide the common case.
-		 *
-		 * We need to stay behind the mount point in case we
-		 * need to do the first walk again (should the create fail).
-		 *
-		 * We also need to cross the mount point and find the directory
-		 * in the union in which we should be creating.
-		 *
-		 * The channel staying behind is c, the one moving forward is cnew.
-		 */
-		m = nil;
-		cnew = nil;	/* is this assignment necessary? */
-		if(!waserror()){	/* try create */
-			if(!nomount && findmount(&cnew, &m, c->type, c->dev, c->qid))
-				cnew = createdir(cnew, m);
-			else{
-				cnew = c;
-				incref(&cnew->ref);
-			}
-
-			/*
-			 * We need our own copy of the Chan because we're
-			 * about to send a create, which will move it.  Once we have
-			 * our own copy, we can fix the name, which might be wrong
-			 * if findmount gave us a new Chan.
-			 */
-			cnew = cunique(cnew);
-			cnameclose(cnew->name);
-			cnew->name = c->name;
-			incref(&cnew->name->ref);
-
-			devtab[cnew->type]->create(cnew, e.elems[e.nelems-1], omode&~(OEXCL|OCEXEC), perm);
-			poperror();
-			if(omode & OCEXEC)
-				cnew->flag |= CCEXEC;
-			if(omode & ORCLOSE)
-				cnew->flag |= CRCLOSE;
-			if(m)
-				putmhead(m);
-			cclose(c);
-			c = cnew;
-			c->name = addelem(c->name, e.elems[e.nelems-1]);
-			break;
-		}else{		/* create failed */
-			cclose(cnew);
-			if(m)
-				putmhead(m);
-			if(omode & OEXCL)
-				nexterror();
-			/* save error */
-			createerr = up->errstr;
-			up->errstr = tmperrbuf;
-			/* note: we depend that walk does not error */
-			if(walk(&c, e.elems+e.nelems-1, 1, nomount, nil) < 0){
-				up->errstr = createerr;
-				error(createerr);	/* report true error */
-			}
-			up->errstr = createerr;
-			omode |= OTRUNC;
-			goto Open;
-		}
-		panic("namec: not reached");				
-
-	default:
-		panic("unknown namec access %d\n", amode);
-	}
-
-	poperror();
-
-	/* place final element in genbuf for e.g. exec */
-	if(e.nelems > 0)
-		kstrcpy(up->genbuf, e.elems[e.nelems-1], sizeof up->genbuf);
-	else
-		kstrcpy(up->genbuf, ".", sizeof up->genbuf);
-	free(e.name);
-	free(e.elems);
-	free(e.off);
-
-	return c;
-}
-
-/*
- * name is valid. skip leading / and ./ as much as possible
- */
-char*
-skipslash(char *name)
-{
-	while(name[0]=='/' || (name[0]=='.' && (name[1]==0 || name[1]=='/')))
-		name++;
-	return name;
-}
-
-char isfrog[256]={
-	/*NUL*/	1, 1, 1, 1, 1, 1, 1, 1,	/* 0 */
-	/*BKS*/	1, 1, 1, 1, 1, 1, 1, 1, /* 0x08 */
-	/*DLE*/	1, 1, 1, 1, 1, 1, 1, 1, /* 0x10 */
-	/*CAN*/	1, 1, 1, 1, 1, 1, 1, 1, /* 0x18 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x20 */
-		0, 0, 0, 0, 0, 0, 0, 1, /* 0x28 (1 is '/', 0x2F) */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x30 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x38 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x48 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x58 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x60 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x68 */
-		0, 0, 0, 0, 0, 0, 0, 0, /* 0x70 */
-		0, 0, 0, 0, 0, 0, 0, 1, /* 0x78 (1 is DEL, 0x7F) */
-};
-
-/*
- * Check that the name
- *  a) is in valid memory.
- *  b) is shorter than 2^16 bytes, so it can fit in a 9P string field.
- *  c) contains no frogs.
- * The first byte is known to be addressible by the requester, so the
- * routine works for kernel and user memory both.
- * The parameter slashok flags whether a slash character is an error
- * or a valid character.
- */
-void
-validname(char *aname, int slashok)
-{
-	char *ename, *name;
-	int c;
-	Rune r;
-
-	name = aname;
-/*
-	if(((ulong)name & KZERO) != KZERO) {
-		p = name;
-		t = BY2PG-((ulong)p&(BY2PG-1));
-		while((ename=vmemchr(p, 0, t)) == nil) {
-			p += t;
-			t = BY2PG;
-		}
-	}else
-*/
-		ename = memchr(name, 0, (1<<16));
-
-	if(ename==nil || ename-name>=(1<<16))
-		error("name too long");
-
-	while(*name){
-		/* all characters above '~' are ok */
-		c = *(uchar*)name;
-		if(c >= Runeself)
-			name += chartorune(&r, name);
-		else{
-			if(isfrog[c])
-				if(!slashok || c!='/'){
-					snprint(up->genbuf, sizeof(up->genbuf), "%s: %q", Ebadchar, aname);
-					error(up->genbuf);
-			}
-			name++;
-		}
-	}
-}
-
-void
-isdir(Chan *c)
-{
-	if(c->qid.type & QTDIR)
-		return;
-	error(Enotdir);
-}
-
-/*
- * This is necessary because there are many
- * pointers to the top of a given mount list:
- *
- *	- the mhead in the namespace hash table
- *	- the mhead in chans returned from findmount:
- *	  used in namec and then by unionread.
- *	- the mhead in chans returned from createdir:
- *	  used in the open/create race protect, which is gone.
- *
- * The RWlock in the Mhead protects the mount list it contains.
- * The mount list is deleted when we cunmount.
- * The RWlock ensures that nothing is using the mount list at that time.
- *
- * It is okay to replace c->mh with whatever you want as 
- * long as you are sure you have a unique reference to it.
- *
- * This comment might belong somewhere else.
- */
-void
-putmhead(Mhead *m)
-{
-	if(m && decref(&m->ref) == 0){
-		m->mount = (Mount*)0xCafeBeef;
-		free(m);
-	}
-}