## diffname port/chan.c 1990/0227
## diff -e /dev/null /n/bootesdump/1990/0227/sys/src/9/mips/chan.c
0a
#include	"u.h"
#include	"lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"errno.h"


struct{
	Lock;
	Chan	*free;
}chanalloc;

int
incref(Ref *r)
{
	lock(r);
	r->ref++;
	unlock(r);
	return r->ref;
}

int
decref(Ref *r)
{
	lock(r);
	r->ref--;
	unlock(r);
	return r->ref;
}

void
chaninit(void)
{
	int i;
	Chan *c;

	chanalloc.free = ialloc(conf.nchan*sizeof(Chan), 0);

	c = chanalloc.free;
	for(i=0; i<conf.nchan-1; i++,c++){
		c->fid = i;
		c->next = c+1;
	}
	c->next = 0;
}

void
chandevreset(void)
{
	int i;

	for(i=0; i<strlen(devchar); i++)
		(*devtab[i].reset)();
}

void
chandevinit(void)
{
	int i;

	for(i=0; i<strlen(devchar); i++)
		(*devtab[i].init)();
}

Chan*
newchan(void)
{
	Chan *c;

loop:
	lock(&chanalloc);
	if(c = chanalloc.free){		/* assign = */
		chanalloc.free = c->next;
		c->flag = 0;
		c->ref = 1;
		unlock(&chanalloc);
		c->offset = 0;
		c->mnt = 0;
		c->stream = 0;
		return c;
	}
	unlock(&chanalloc);
	print("no chans\n");
	if(u == 0)
		panic("newchan");
	u->p->state = Wakeme;
	alarm(1000, wakeme, u->p);
	sched();
	goto loop;
}

void
close(Chan *c)
{
	if(decref(c) == 0){
		if(!waserror()){
			(*devtab[c->type].close)(c);
			poperror();
		}
		lock(&chanalloc);
		c->next = chanalloc.free;
		chanalloc.free = c;
		unlock(&chanalloc);
	}
}

int
eqchan(Chan *a, Chan *b, long qmask)
{
	if((a->qid^b->qid) & qmask)
		return 0;
	if(a->type != b->type)
		return 0;
	if(a->dev != b->dev)
		return 0;
	return 1;
}

/*
 * omnt is locked.  return with nmnt locked.
 */
Mount*
mountsplit(Mount *omnt)
{
	Mount *nmnt;

	print("mount copy on write\n");
	nmnt = newmount();
	lock(nmnt);
	nmnt->term = omnt->term;
	nmnt->mountid = omnt->mountid;
	nmnt->next = omnt->next;
	if(nmnt->next)
		incref(nmnt);
	nmnt->c = omnt->c;
	incref(nmnt->c);
	omnt->ref--;
	unlock(omnt);
	return nmnt;
}

int
mount(Chan *new, Chan *old, int flag)
{
	int i;
	Mtab *mt, *mz;
	Mount *mnt, *omnt, *nmnt, *pmnt;
	Pgrp *pg;
	int isnew;

	if(CHDIR & (old->qid^new->qid))
		error(0, Emount);
	if((old->qid&CHDIR)==0 && (flag&MORDER)!=MREPL)
		error(0, Emount);

	mz = 0;
	isnew = 0;
	pg = u->p->pgrp;
	lock(pg);
	if(waserror()){
		unlock(pg);
		nexterror();
	}
	/*
	 * Is old already in mount table?
	 */
	mt = pg->mtab;
	for(i=0; i<pg->nmtab; i++,mt++){
		if(mt->c==0 && mz==0)
			mz = mt;
		else if(eqchan(mt->c, old, CHDIR|QPATH))
			goto Found;
	}
	isnew = 1;
	if(mz == 0){
		if(i == conf.nmtab)
			error(0, Enomount);
		mz = &pg->mtab[i];
		pg->nmtab++;
	}
	mz->mnt = 0;
	mz->c = old;
	mt = mz;

    Found:
	new->flag = CMOUNT;
	if(flag & MCREATE)
		new->flag |= CCREATE;
	mnt = newmount();
	mnt->c = new;

	switch(flag & MORDER){
	/*
	 * These two always go at head of list
	 */
	case MBEFORE:
		if(mt->mnt == 0)
			error(0, Enotunion);
		/* fall through */

	case MREPL:
		omnt = mt->mnt;
		if(omnt)
			incref(omnt);
		mnt->next = omnt;
		mt->mnt = mnt;
		mnt->term = 1;
		if((flag&MORDER) == MBEFORE)
			mnt->term = 0;
		break;

	/*
	 * This one never goes at head of list
	 */
	case MAFTER:
		if(mt->mnt == 0)
			error(0, Enotunion);
		omnt = mt->mnt;
		pmnt = 0;
		while(!omnt->term){
			lock(omnt);
			if(omnt->ref > 1){
				omnt = mountsplit(omnt);
				if(pmnt)
					pmnt->next = omnt;
				else
					mt->mnt = omnt;
			}
			unlock(omnt);
			nmnt = omnt->next;
			if(nmnt == 0)
				panic("MAFTER term");
			pmnt = omnt;
			omnt = nmnt;
		}
		mnt->next = omnt->next;
		omnt->next = mnt;
		mnt->term = 1;
		omnt->term = 0;
		break;
	}

	incref(new);
	if(isnew)
		incref(old);
	unlock(pg);
	poperror();
	return mnt->mountid;
}

Chan*
clone(Chan *c, Chan *nc)
{
	return (*devtab[c->type].clone)(c, nc);
}

Chan*
domount(Chan *c)
{
	int i;
	ulong mntid;
	Mtab *mt;
	Mount *mnt;
	Pgrp *pg;
	Chan *nc, *mc;

	pg = u->p->pgrp;
	/*
	 * Is c in in mount table?
	 */
	mt = pg->mtab;
	for(i=0; i<pg->nmtab; i++,mt++)
		if(mt->c && eqchan(mt->c, c, CHDIR|QPATH))
			goto Found;
	/*
	 * No; c is unaffected
	 */
	return c;

	/*
	 * Yes; move c through table
	 */
    Found:
	lock(pg);
	if(!eqchan(mt->c, c, CHDIR|QPATH)){	/* table changed underfoot */
		print("domount: changed underfoot?\n");
		unlock(pg);
		return c;
	}
	mnt = mt->mnt;
	mntid = mnt->mountid;
	mc = mnt->c;
	incref(mc);
	unlock(pg);
	if(waserror()){
		close(mc);
		nexterror();
	}
	nc = clone(mc, 0);
	close(mc);
	poperror();
	close(c);
	nc->mnt = mnt;
	nc->mountid = mntid;
	return nc;
}

Chan*
walk(Chan *ac, char *name, int domnt)
{
	Mount *mnt;
	int first = 1;
	Chan *c = ac;
	Chan *nc, *mc;
	Pgrp *pg = u->p->pgrp;

	/*
	 * name may be empty if the file name is "/", "#c" etc.
	 */
    Again:
	if(name[0] && (*devtab[c->type].walk)(c, name)==0){
		if(!(c->flag&CMOUNT))
			goto Notfound;
		mnt = c->mnt;
		if(mnt == 0)
			panic("walk");
		lock(pg);
		if(mnt->term){
			unlock(pg);
			goto Notfound;
		}
		if(c->mountid != mnt->mountid){
			print("walk: changed underfoot?\n");
			unlock(pg);
			goto Notfound;
		}
		mnt = mnt->next;
		mc = mnt->c;
		incref(mc);
		unlock(pg);
		if(waserror()){
			close(mc);
			nexterror();
		}
		if(mnt == 0)
			panic("walk 1");
		nc = clone(mc, 0);
		close(mc);
		poperror();
		if(!first)
			close(c);
		nc->mnt = mnt;
		c = nc;
		first = 0;
		goto Again;
	}

	if(name[0])			/* walk succeeded */
		c->flag &= ~CMOUNT;

	if(!first)
		close(ac);

	if(domnt)
		return domount(c);
	return c;

    Notfound:
	if(!first)
		close(c);
	return 0;
}

/*
 * c is a mounted non-creatable directory.  find a creatable one.
 */
Chan*
createdir(Chan *c)
{
	Mount *mnt;
	Pgrp *pg = u->p->pgrp;
	Chan *mc, *nc;

	lock(pg);
	if(waserror()){
		unlock(pg);
		nexterror();
	}
	mnt = c->mnt;
	if(c->mountid != mnt->mountid){
		print("createdir: changed underfoot?\n");
		error(0, Enocreate);
	}
	do{
		if(mnt->term)
			error(0, Enocreate);
		mnt = mnt->next;
	}while(!(mnt->c->flag&CCREATE));
	mc = mnt->c;
	incref(mc);
	unlock(pg);
	if(waserror()){
		close(mc);
		nexterror();
	}
	nc = clone(mc, 0);
	poperror();
	close(c);
	close(mc);
	nc->mnt = mnt;
	return nc;
}

/*
 * Turn a name into a channel.
 * &name[0] is known to be a valid address.  It may be a kernel address.
 */
Chan*
namec(char *name, int amode, int omode, ulong perm)
{
	Chan *c, *nc;
	int t;
	int mntok;
	char *elem = u->elem;

	if(name[0] == 0)
		error(0, Enonexist);
	mntok = 1;
	if(name[0] == '/'){
		c = clone(u->slash, 0);
		/*
		 * Skip leading slashes.
		 */
		name = skipslash(name);
	}else if(name[0] == '#'){
		mntok = 0;
		if(!((ulong)name & KZERO))
			validaddr((ulong)(name+1), 2, 0);
		if(name[1]=='|' || ('A'<=name[1] && name[1]<='Z'))
			error(0, Enonexist);
		t = devno(name[1], 1);
		if(t == -1)
			error(0, Ebadsharp);
		name += 2;
		if(*name == '/'){
			name = skipslash(name);
			elem[0]=0;
		}else
			name = nextelem(name, elem);
		c = (*devtab[t].attach)(elem);
	}else
		c = clone(u->dot, 0);

	if(waserror()){
		close(c);
		nexterror();
	}

	name = nextelem(name, elem);
	if(mntok)
	if(!(amode==Amount && elem[0]==0))	/* don't domount on dot or slash */
		c = domount(c);			/* see case Atodir below */

	/*
	 * How to treat the last element of the name depends on the operation.
	 * Therefore do all but the last element by the easy algorithm.
	 */
	while(*name){
		if((nc=walk(c, elem, mntok)) == 0)
			error(0, Enonexist);
		c = nc;
		name = nextelem(name, elem);
	}
	/*
	 * Last element; act according to type of access.
	 */

	switch(amode){
	case Aaccess:
		if((nc=walk(c, elem, mntok)) == 0)
			error(0, Enonexist);
		c = nc;
		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((nc=walk(c, elem, 0)) == 0)
			error(0, Enonexist);
		c = nc;
		if(!(c->qid & CHDIR))
			error(0, Enotdir);
		break;

	case Aopen:
		if((nc=walk(c, elem, mntok)) == 0)
			error(0, Enonexist);
		c = nc;
	Open:
		c = (*devtab[c->type].open)(c, omode);
		break;

	case Amount:
		/*
		 * When mounting on an already mounted upon directory, one wants
		 * the second mount to be attached to the original directory, not
		 * the replacement.
		 */
		if((nc=walk(c, elem, 0)) == 0)
			error(0, Enonexist);
		c = nc;
		break;

	case Acreate:
		if((nc=walk(c, elem, 1)) != 0){
			c = nc;
			omode |= OTRUNC;
			goto Open;
		}
		if((c->flag&(CMOUNT|CCREATE)) == CMOUNT)
			c = createdir(c);
		(*devtab[c->type].create)(c, elem, omode, perm);
		break;

	default:
		panic("unknown namec access %d\n", amode);
	}
	poperror();
	return c;
}

/*
 * name[0] is addressable.
 */
char*
skipslash(char *name)
{
	while(*name == '/'){
		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
			validaddr((ulong)name+1, 1, 0);
		name++;
	}
	return name;
}

char isfrog[]={
	/*NUL*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*BKS*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*DLE*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*CAN*/	1, 1, 1, 1, 1, 1, 1, 1,
	[' ']	1,
	['/']	1,
	[0x7f]	1,
};

/*
 * name[0] should not be a slash.
 * Advance name to next element in path, copying current element into elem.
 * Return pointer to next element, skipping slashes.
 * &name[0] is known to be a valid address.
 */
char*
nextelem(char *name, char *elem)
{
	int i, user, c;
	char *end, *e;

	if(*name == '/')
		error(0, Efilename);
	end = vmemchr(name, 0, NAMELEN);
	if(end == 0){
		end = vmemchr(name, '/', NAMELEN);
		if(end == 0)
			error(0, Efilename);
	}else{
		e = memchr(name, '/', end-name);
		if(e)
			end = e;
	}
	while(name < end){
		c = *name++;
		if((c&0x80) || isfrog[c])
			error(0, Ebadchar);
		*elem++ = c;
	}
	*elem = 0;
	return skipslash(name);
}

void
isdir(Chan *c)
{
	if(c->qid & CHDIR)
		return;
	error(0, Enotdir);
}
.
## diffname port/chan.c 1990/0303
## diff -e /n/bootesdump/1990/0227/sys/src/9/mips/chan.c /n/bootesdump/1990/0303/sys/src/9/mips/chan.c
80a
		c->mchan = 0;
		c->mqid = 0;
.
## diffname port/chan.c 1990/0321
## diff -e /n/bootesdump/1990/0303/sys/src/9/mips/chan.c /n/bootesdump/1990/0321/sys/src/9/mips/chan.c
394c
		pprint("createdir: changed underfoot?\n");
.
355a
		nc->mountid = mnt->mountid;
.
336c
			pprint("walk: changed underfoot?\n");
.
289c
		pprint("domount: changed underfoot?\n");
.
248a
	}
	if(islast)
		pg->nmtab++;
.
247c
	if(mz){
		mz->c = old;
.
185d
182c
		islast++;
.
177d
175a
		}
.
174c
		else if(eqchan(mt->c, old, CHDIR|QPATH)){
			mz = 0;
.
163a
		if(mnt){
			mnt->c = 0;	/* caller will close new */
			closemount(mnt);
		}
.
160c
	islast = 0;
	mnt = 0;
.
152c
	int islast;
.
## diffname port/chan.c 1990/0513
## diff -e /n/bootesdump/1990/0321/sys/src/9/mips/chan.c /n/bootesdump/1990/0513/sys/src/9/mips/chan.c
494a
		}
.
493c
		if((nc=walk(c, elem, mntok)) == 0){
			print("%d pc %lux\n", u->nerrlab, u->errlab[u->nerrlab-1].pc);
.
## diffname port/chan.c 1990/0515
## diff -e /n/bootesdump/1990/0513/sys/src/9/mips/chan.c /n/bootesdump/1990/0515/sys/src/9/mips/chan.c
496d
493,494c
		if((nc=walk(c, elem, mntok)) == 0)
.
## diffname port/chan.c 1990/0603
## diff -e /n/bootesdump/1990/0515/sys/src/9/mips/chan.c /n/bootesdump/1990/0603/sys/src/9/mips/chan.c
217a
		else
			mnt->term = 1;
.
215d
210,213c
		mnt->next = mt->mnt;
.
137c
		incref(nmnt->next);
.
## diffname port/chan.c 1990/0617
## diff -e /n/bootesdump/1990/0603/sys/src/9/mips/chan.c /n/bootesdump/1990/0617/sys/src/9/mips/chan.c
130d
## diffname port/chan.c 1990/0707
## diff -e /n/bootesdump/1990/0617/sys/src/9/mips/chan.c /n/bootesdump/1990/0707/sys/src/9/mips/chan.c
74a
		c->type = 0;	/* if closed before changed, this calls rooterror, a nop */
.
## diffname port/chan.c 1990/08141
## diff -e /n/bootesdump/1990/0707/sys/src/9/mips/chan.c /n/bootesdump/1990/08141/sys/src/9/mips/chan.c
535a
		if(omode & OCEXEC)
			c->flag |= CCEXEC;
.
513a
		if(omode & OCEXEC)
			c->flag |= CCEXEC;
.
450c
		if(name[1]=='|' || name[1]=='M')
.
## diffname port/chan.c 1990/0820
## diff -e /n/bootesdump/1990/08141/sys/src/9/mips/chan.c /n/bootesdump/1990/0820/sys/src/9/mips/chan.c
558a
	}
	if(*name == '.'){
		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
			validaddr((ulong)name+1, 1, 0);
		if(name[1]==0 || name[1]=='/'){
			name++;
			goto Again;
		}
.
554a
    Again:
.
529a
		if(isdot)
			error(0, Eisdir);
.
509,511c
		if(isdot)
			c = domount(c);
		else{
			if((nc=walk(c, elem, mntok)) == 0)
				error(0, Enonexist);
			c = nc;
		}
.
491,493c
		if(isdot)
			c = domount(c);
		else{
			if((nc=walk(c, elem, mntok)) == 0)
				error(0, Enonexist);
			c = nc;
		}
.
484a

.
471,472c

	if(mntok && !isdot)
	if(!(amode==Amount && elem[0]==0))	/* don't domount on slash */
.
463a
		name = skipslash(name);	/* eat leading ./ */
		if(*name == 0)
			isdot = 1;
	}
.
462c
	}else{
.
439a
	isdot = 0;
.
434c
	int mntok, isdot;
.
343c
			pprint("walk: changed underfoot? '%s'\n", name);
.
## diffname port/chan.c 1990/0821
## diff -e /n/bootesdump/1990/0820/sys/src/9/mips/chan.c /n/bootesdump/1990/0821/sys/src/9/mips/chan.c
615c
		end = memchr(name, '/', NAMELEN);
.
613c
	end = memchr(name, 0, NAMELEN);
.
603d
578,585d
576a
	if(*name=='.' && (name[1]==0 || name[1]=='/')){
		name++;
		goto Again;
.
573,575c
	while(*name == '/')
.
449,450d
438a

	/*
	 * Make sure all of name is o.k.  first byte is validated
	 * externally so if it's a kernel address we know it's o.k.
	 */
	if(!((ulong)name & KZERO)){
		p = name;
		t = BY2PG-((ulong)p&(BY2PG-1));
		while(vmemchr(p, 0, t) == 0){
			p += t;
			t = BY2PG;
		}
	}

	elem = u->elem;
.
435c
	char *p;
	char *elem;
.
## diffname port/chan.c 1990/0907
## diff -e /n/bootesdump/1990/0821/sys/src/9/mips/chan.c /n/bootesdump/1990/0907/sys/src/9/mips/chan.c
103a
		c->flag = CFREE;
.
98a
	if(c->flag & CFREE)
		panic("close");
.
## diffname port/chan.c 1990/0914
## diff -e /n/bootesdump/1990/0907/sys/src/9/mips/chan.c /n/bootesdump/1990/0914/sys/src/9/mips/chan.c
544a
		saveregisters();	/* else error() in open has wrong value of c saved */
.
427a
void
saveregisters(void)
{
}

.
378,379c

.
374a
	if(domnt){
		if(waserror()){
			print("domount error\n");
			if(!first)
				close(c);
			return 0;
		}
		c = domount(c);
		poperror();
	}

.
## diffname port/chan.c 1990/09141
## diff -e /n/bootesdump/1990/0914/sys/src/9/mips/chan.c /n/bootesdump/1990/09141/sys/src/9/mips/chan.c
377d
## diffname port/chan.c 1990/1009
## diff -e /n/bootesdump/1990/09141/sys/src/9/mips/chan.c /n/bootesdump/1990/1009/sys/src/9/mips/chan.c
482c
		if(name[1]=='M')
.
## diffname port/chan.c 1990/1104
## diff -e /n/bootesdump/1990/1009/sys/src/9/mips/chan.c /n/bootesdump/1990/1104/sys/src/9/mips/chan.c
29c
	return x;
.
27c
	x = --r->ref;
.
25a
	int x;

.
20c
	return x;
.
18c
	x = ++r->ref;
.
16a
	int x;

.
## diffname port/chan.c 1990/11211
## diff -e /n/bootesdump/1990/1104/sys/src/9/mips/chan.c /n/bootesdump/1990/11211/sys/src/9/mips/chan.c
666c
	error(Enotdir);
.
664c
	if(c->qid.path & CHDIR)
.
654c
			error(Ebadchar);
.
645c
			error(Efilename);
.
640c
		error(Efilename);
.
582c
			error(Eisdir);
.
576c
			error(Enonexist);
.
559c
				error(Enonexist);
.
550,551c
		if(!(c->qid.path & CHDIR))
			error(Enotdir);
.
548c
			error(Enonexist);
.
537c
				error(Enonexist);
.
522c
			error(Enonexist);
.
490c
			error(Ebadsharp);
.
487c
			error(Enonexist);
.
460c
		error(Enonexist);
.
423c
			error(Enocreate);
.
419c
		error(Enocreate);
.
230c
			error(Enotunion);
.
213c
			error(Enotunion);
.
193c
			error(Enomount);
.
161,164c
	if(CHDIR & (old->qid.path^new->qid.path))
		error(Emount);
	if((old->qid.path&CHDIR)==0 && (flag&MORDER)!=MREPL)
		error(Emount);
.
122a
	if(!pathonly && a->qid.vers!=b->qid.vers)
		return 0;
.
121c
	return a.path==b.path && a.vers==b.vers;
}

int
eqchan(Chan *a, Chan *b, int pathonly)
{
	if(a->qid.path != b->qid.path)
.
119c
eqqid(Qid a, Qid b)
.
87c
		c->mqid = (Qid){0, 0};
.
82a
		c->dev = 0;
.
## diffname port/chan.c 1990/1122
## diff -e /n/bootesdump/1990/11211/sys/src/9/mips/chan.c /n/bootesdump/1990/1122/sys/src/9/mips/chan.c
311c
	if(!eqchan(mt->c, c, 1)){	/* table changed underfoot */
.
299c
		if(mt->c && eqchan(mt->c, c, 1))
.
195c
		else if(eqchan(mt->c, old, 1)){
.
## diffname port/chan.c 1991/0413
## diff -e /n/bootesdump/1990/1210/sys/src/9/mips/chan.c /n/bootesdump/1991/0413/sys/src/9/port/chan.c
111,115c
		(*devtab[c->type].close)(c);
		freechan(c);
		poperror();
.
107,109c
		if(waserror()) {
			freechan(c);
			nexterror();
.
101a
freechan(Chan *c)
{
	c->flag = CFREE;
	lock(&chanalloc);
	c->next = chanalloc.free;
	chanalloc.free = c;
	unlock(&chanalloc);
}

void
.
## diffname port/chan.c 1991/0414
## diff -e /n/bootesdump/1991/0413/sys/src/9/port/chan.c /n/bootesdump/1991/0414/sys/src/9/port/chan.c
121,123c
		c->flag = CFREE;
		lock(&chanalloc);
		c->next = chanalloc.free;
		chanalloc.free = c;
		unlock(&chanalloc);
.
117,119c
		if(!waserror()) {
			(*devtab[c->type].close)(c);
			poperror();
.
104,108c
	if(decref(c) == 0){
		c->flag = CFREE;
		lock(&chanalloc);
		c->next = chanalloc.free;
		chanalloc.free = c;
		unlock(&chanalloc);
	}
.
## diffname port/chan.c 1991/0416
## diff -e /n/bootesdump/1991/0414/sys/src/9/port/chan.c /n/bootesdump/1991/0416/sys/src/9/port/chan.c
551d
533,534c
	/*
	 *  If mounting, don't follow the mount entry for root or the
	 *  current directory.
	 */
	if(mntok && !isdot && !(amode==Amount && elem[0]==0))
.
## diffname port/chan.c 1991/0421
## diff -e /n/bootesdump/1991/0416/sys/src/9/port/chan.c /n/bootesdump/1991/0421/sys/src/9/port/chan.c
86a
		c->aux = 0;
		c->mntindex = 0;
.
## diffname port/chan.c 1991/0423
## diff -e /n/bootesdump/1991/0421/sys/src/9/port/chan.c /n/bootesdump/1991/0423/sys/src/9/port/chan.c
624c
	if(f.c->flag & CMOUNT){
		f.c->mnt = f.mnt;
		f.c->mountid = f.mountid;
	}
	return f.c;
.
622a
	if(f.needcl)
		doclone(&f);
.
617c
			f.c->flag |= CCEXEC;
.
613,615c
		if((f.c->flag&(CMOUNT|CCREATE)) == CMOUNT)
			createdir(&f);
		if(f.needcl)
			doclone(&f);
		(*devtab[f.c->type].create)(f.c, elem, omode, perm);
.
608,609c
		if(walk(&f, elem, 1) != 0){
.
602d
600c
		if(walk(&f, elem, 0) == 0)
.
591c
			f.c->flag |= CCEXEC;
.
588,589c
		saveregisters(); /* else error() in open has wrong value of c saved */
		if(f.needcl)
			doclone(&f);
		f.c = (*devtab[f.c->type].open)(f.c, omode);
.
585d
583c
			if(walk(&f, elem, mntok) == 0)
.
581c
			domount(&f);
.
574,575c
		if(!(f.c->qid.path & CHDIR))
.
572c
		if(walk(&f, elem, 0) == 0)
.
563d
561c
			if(walk(&f, elem, mntok) == 0)
.
559c
			domount(&f);
.
549d
547c
		if(walk(&f, elem, mntok) == 0)
.
540c
		domount(&f);		/* see case Atodir below */
.
529c
		close(f.c);
.
522c
		f.c = u->dot;
		incref(f.c);
		f.needcl = 1;
.
520c
		f.c = (*devtab[t].attach)(elem);
		f.needcl = 0;
.
502c
		f.c = u->slash;
		incref(f.c);
		f.needcl = 1;
.
500a
	f.mnt = 0;
.
480a
	Finger f;
.
476d
468a
void
doclone(Finger *f)
{
	Chan *nc;

	if(f->needcl == 0)
		return;
	nc = clone(f->c, 0);
	close(f->c);
	f->c = nc;
	f->needcl = 0;
}

.
458,461c
	close(f->c);
	f->needcl = 1;
	f->c = mc;
.
452,456d
439,440c
	mnt = f->mnt;
	if(f->mountid != mnt->mountid){
.
432c
	Chan *mc;
.
427,428c
void
createdir(Finger *f)
.
425c
 * f->c is a mounted non-creatable directory.  find a creatable one.
.
416,417d
414a
	return 1;
.
412,413c
	if(domnt)
		domount(f);
.
408,409c

		/*
		 *  we get here only if we have a cloned and walked
		 *  channel
		 */
		if(!first)
			close(f->c);
		f->c = c;
		f->needcl = 0;
		f->mnt = 0;
		c->flag &= ~CMOUNT;
.
406c
			c = mc;
			first = 0;
.
370,403d
360,368c
	if(name[0]){
		for(;;){
			if(!first || f->needcl){
				mc = (*devtab[c->type].clwalk)(c, name);
				if(mc){
					close(c);
					c = mc;
					break;
				}
			} else {
				if((*devtab[c->type].walk)(c, name) != 0){
					break;
				}
			}
			if(!(c->flag&CMOUNT))
				goto Notfound;
			if(mnt == 0)
				panic("walk");	/* ??? is this safe ??? */
			lock(pg);
			if(mnt->term){
				unlock(pg);
				goto Notfound;
			}
			if(mountid != mnt->mountid){
				pprint("walk: changed underfoot? '%s'\n", name);
				unlock(pg);
				goto Notfound;
			}
			mnt = mnt->next;
			mountid = mnt->mountid;
			mc = mnt->c;
			incref(mc);
.
353,354c
	Mount *mnt = f->mnt;
	ulong mountid = f->mountid;
	Chan *c = f->c;
	Chan *mc;
.
351d
348,349c
int
walk(Finger *f, char *name, int domnt)
.
335,345c
	close(f->c);
	f->c = mc;
	f->needcl = 1;
.
330,332c
	f->mnt = mt->mnt;
	f->mountid = f->mnt->mountid;
	mc = mt->mnt->c;
.
328c
		return;
.
325c
	if(!eqchan(mt->c, f->c, 1)){	/* table changed underfoot */
.
318c
	return;
.
313c
		if(mt->c && eqchan(mt->c, f->c, 1))
.
305c
	Chan *mc;
.
303d
301d
297,298c
void
domount(Finger *f)
.
88d
86d
13a
/*
 *  used by namec, domount, and walk to point
 *  to the current mount entry during name resolution
 */
typedef struct Finger	Finger;
struct Finger {
	Chan	*c;		/* channel we're walking */
	int	needcl;		/* true if we need to clone c before using it */
	Mount	*mnt;		/* last mount point we ran traversed */
	ulong	mountid;	/* id of that mount point */
};

.
## diffname port/chan.c 1991/0426
## diff -e /n/bootesdump/1991/0423/sys/src/9/port/chan.c /n/bootesdump/1991/0426/sys/src/9/port/chan.c
114,125d
## diffname port/chan.c 1991/0427
## diff -e /n/bootesdump/1991/0426/sys/src/9/port/chan.c /n/bootesdump/1991/0427/sys/src/9/port/chan.c
624,628c
	return c;
.
621,622d
615c
			c->flag |= CCEXEC;
.
609,613c
		close(cc);
		poperror();

		/*
		 *  the file didn't exist, try the create
		 */
		if((c->flag&(CMOUNT|CCREATE)) == CMOUNT)
			c = createdir(c);
		(*devtab[c->type].create)(c, elem, omode, perm);
.
605c

		/*
		 *  Walk the element before trying to create it
		 *  to see if it exists.  We clone the channel
		 *  first, just in case someone is trying to
		 *  use clwalk outside the kernel.
		 */
		cc = clone(c, 0);
		if(waserror()){
			close(cc);
			nexterror();
		}
		if((nc=walk(cc, elem, 1)) != 0){
			poperror();
			close(c);
			c = nc;
.
599a
		c = nc;
.
598c
		if((nc=walk(c, elem, 0)) == 0)
.
589c
			c->flag |= CCEXEC;
.
584,587c
		saveregisters();	/* else error() in open has wrong value of c saved */
		c = (*devtab[c->type].open)(c, omode);
.
581a
			c = nc;
.
580c
			if((nc=walk(c, elem, mntok)) == 0)
.
578c
			c = domount(c);
.
572c
		c = nc;
		if(!(c->qid.path & CHDIR))
.
570c
		if((nc=walk(c, elem, 0)) == 0)
.
561a
			c = nc;
.
560c
			if((nc=walk(c, elem, mntok)) == 0)
.
558c
			c = domount(c);
.
548a
		c = nc;
.
547c
		if((nc=walk(c, elem, mntok)) == 0)
.
540c
		c = domount(c);			/* see case Atodir below */
.
529c
		close(c);
.
520,522c
		c = clone(u->dot, 0);
.
517,518c
		c = (*devtab[t].attach)(elem);
.
497,499c
		c = clone(u->slash, 0);
.
495d
474d
469a
	Chan *c, *nc, *cc;
.
450,462d
440,442c
	close(c);
	close(mc);
	nc->mnt = mnt;
	return nc;
.
438a
	if(waserror()){
		close(mc);
		nexterror();
	}
	nc = clone(mc, 0);
.
426,427c
	mnt = c->mnt;
	if(c->mountid != mnt->mountid){
.
419c
	Chan *mc, *nc;
.
414,415c
Chan*
createdir(Chan *c)
.
412c
 * c is a mounted non-creatable directory.  find a creatable one.
.
404a
	return c;

.
403d
400,401c
	if(!first)
		close(ac);
.
397a

	if(domnt){
		if(waserror()){
			if(!first)
				close(c);
			return 0;
		}
		c = domount(c);
		poperror();
.
393,396c
			close(c);
		nc->mnt = mnt;
		nc->mountid = mnt->mountid;
		c = nc;
		first = 0;
		goto Again;
	}

	if(name[0])			/* walk succeeded */
.
387,391c
		if(c->mountid != mnt->mountid){
			pprint("walk: changed underfoot? '%s'\n", name);
			unlock(pg);
			goto Notfound;
		}
		mnt = mnt->next;
		mc = mnt->c;
		incref(mc);
		unlock(pg);
		if(waserror()){
			close(mc);
			nexterror();
		}
		if(mnt == 0)
			panic("walk 1");
		nc = clone(mc, 0);
		close(mc);
		poperror();
.
382,385c
			goto Notfound;
.
349,380c
    Again:
	if(name[0] && (*devtab[c->type].walk)(c, name)==0){
		if(!(c->flag&CMOUNT))
			goto Notfound;
		mnt = c->mnt;
		if(mnt == 0)
			panic("walk");
		lock(pg);
		if(mnt->term){
.
340,343c
	Chan *c = ac;
	Chan *nc, *mc;
.
338a
	Mount *mnt;
.
336,337c
Chan*
walk(Chan *ac, char *name, int domnt)
.
331,333c
	if(waserror()){
		close(mc);
		nexterror();
	}
	nc = clone(mc, 0);
	close(mc);
	poperror();
	close(c);
	nc->mnt = mnt;
	nc->mountid = mntid;
	return nc;
.
326,328c
	mnt = mt->mnt;
	mntid = mnt->mountid;
	mc = mnt->c;
.
324c
		return c;
.
321c
	if(!eqchan(mt->c, c, 1)){	/* table changed underfoot */
.
314c
	return c;
.
309c
		if(mt->c && eqchan(mt->c, c, 1))
.
301c
	Chan *nc, *mc;
.
299a
	Mount *mnt;
.
298a
	ulong mntid;
.
295,296c
Chan*
domount(Chan *c)
.
98a
		c->mntindex = 0;
.
97a
		c->stream = 0;
.
14,25d
## diffname port/chan.c 1991/0705
## diff -e /n/bootesdump/1991/0427/sys/src/9/port/chan.c /n/bootesdump/1991/0705/sys/src/9/port/chan.c
32a
	if(x < 0)
		panic("decref");
.
## diffname port/chan.c 1991/0722
## diff -e /n/bootesdump/1991/0705/sys/src/9/port/chan.c /n/bootesdump/1991/0722/sys/src/9/port/chan.c
34a
	}
.
33c
	if(x < 0) {
		if(u) {
			print("%d: %s %lux %lux\n", u->p->pid, u->p->text, *(ulong*)((Ureg*)UREGADDR)->pc, r);
			for(i = 0; i < NSEG; i++) {
				s = u->p->seg[i];
				if(s)
					print("%d: %lux %lux %lux", i, s, s->base, s->top);
			}
		}
.
28a
	int i;
	Segment *s;
.
24a
#include "ureg.h"

.
## diffname port/chan.c 1991/0723
## diff -e /n/bootesdump/1991/0722/sys/src/9/port/chan.c /n/bootesdump/1991/0723/sys/src/9/port/chan.c
47c

.
37,45c
	if(x < 0) 
.
## diffname port/chan.c 1991/0727
## diff -e /n/bootesdump/1991/0723/sys/src/9/port/chan.c /n/bootesdump/1991/0727/sys/src/9/port/chan.c
666a

void
nameok(char *elem)
{
	while(*elem) {
		if((*elem&0x80) || isfrog[*elem])
			error(Ebadchar);
		elem++;
	}
}
.
614a
		nameok(elem);
.
8d
## diffname port/chan.c 1991/0912
## diff -e /n/bootesdump/1991/0727/sys/src/9/port/chan.c /n/bootesdump/1991/0912/sys/src/9/port/chan.c
445a
	poperror();
.
## diffname port/chan.c 1991/1011
## diff -e /n/bootesdump/1991/0912/sys/src/9/port/chan.c /n/bootesdump/1991/1011/sys/src/9/port/chan.c
629c
		if(c->mnt && !(c->flag&CCREATE))
.
583c
		/* else error() in open has wrong value of c saved */
		saveregisters();	
.
475c
	char *elem, *nn;
.
438,456c
	error(Enocreate);
.
433,436c
	for(f = c->mnt; f; f = f->next) {
		if(f->to->flag&CCREATE) {
			nc = clone(f->to, 0);
			nc->mnt = f;
			runlock(&pg->ns);
			close(c);
			return nc;
		}
.
428,430c
	pg = u->p->pgrp;
	rlock(&pg->ns);
	if(waserror()) {
		runlock(&pg->ns);
.
424,426c
	Pgrp *pg;
	Chan *nc;
	Mount *f;
.
415c
		c = 0;
	}
	poperror();
	runlock(&pg->ns);

	if(c) {
		if(dotdot)
			c = undomount(c);
		c->mnt = 0;
		if(domnt) {
			if(waserror()) {
				close(c);
				nexterror();
			}
			c = domount(c);
			poperror();
		}
		close(ac);
	}
	return c;	
.
412,413c
	if((*devtab[ac->type].walk)(ac, name) != 0) {
		if(dotdot)
			ac = undomount(ac);
		if(domnt)
			ac = domount(ac);
		return ac;
	}

	if(ac->mnt == 0) 
		return 0;

	pg = u->p->pgrp;
	rlock(&pg->ns);
	if(waserror()) {
		runlock(&pg->ns);
		if(c)
			close(c);
		nexterror();
	}
	for(f = ac->mnt; f; f = f->next) {
		c = clone(f->to, 0);
		if((*devtab[c->type].walk)(c, name) != 0)
			break;
.
410c
	dotdot = 0;
	if(name[0] == '.')
	if(name[1] == '.')
	if(name[2] == '\0') {
		ac = undomount(ac);
		dotdot = 1;
	}
.
408a
	if(*name == '\0')
		return ac;
.
406,407c
Chan*
walk(Chan *ac, char *name, int domnt)
{
	Pgrp *pg;
	Chan *c = 0;
	Mount *f;
	int dotdot;
.
404a
	poperror();
	runlock(&pg->ns);
	return c;
}
.
402,403d
393,400c
	he = &pg->mnthash[MNTHASH];
	for(h = pg->mnthash; h < he; h++) {
		for(f = *h; f; f = f->hash) {
			for(t = f->mount; t; t = t->next)
				if(eqchan(c, t->to, 1)) {
					close(c);
					c = clone(t->head->from, 0);
					break;
				}
.
351,390c
	pg = u->p->pgrp;
	rlock(&pg->ns);
	if(waserror()) {
		runlock(&pg->ns);
		nexterror();
.
345,349c
	Pgrp *pg;
	Mhead **h, **he, *f;
	Mount *t;
.
343c
undomount(Chan *c)
.
336,339c
	runlock(&pg->ns);
	return c;
.
333,334c
	c->mnt = 0;

	for(m = MOUNTH(pg, c); m; m = m->hash)
		if(eqchan(m->from, c, 1)) {
			nc = clone(m->mount->to, 0);
			nc->mnt = m->mount;
			nc->mountid = m->mount->mountid;
			close(c);
			c = nc;	
			break;			
		}

.
302,330c
	rlock(&pg->ns);
	if(waserror()) {
		runlock(&pg->ns);
.
299c
	Chan *nc;
	Mhead *m;
.
294,297d
278,282c

	if(mounted == 0) {
		*l = m->hash;
		wunlock(&pg->ns);
		mountfree(m->mount);
		close(m->from);
		mntheadfree(m);
		return;
	}

	p = &m->mount;
	for(f = *p; f; f = f->next) {
		if(eqchan(f->to, mounted, 1)) {
			*p = f->next;
			f->next = 0;
			mountfree(f);
			if(m->mount == 0) {
				*l = m->hash;
				wunlock(&pg->ns);
				close(m->from);
				mntheadfree(m);
				return;
			}
			wunlock(&pg->ns);
			return;
		}
		p = &f->next;
	}
	wunlock(&pg->ns);
	errors("not in union");
.
273,276c
	if(m == 0) {
		wunlock(&pg->ns);
		errors("not mounted");
.
242,270c
void
unmount(Chan *mnt, Chan *mounted)
{
	Pgrp *pg;
	Mhead *m, **l;
	Mount *f, **p;

	pg = u->p->pgrp;
	wlock(&pg->ns);

	l = &MOUNTH(pg, mnt);
	for(m = *l; m; m = m->hash) {
		if(eqchan(m->from, mnt, 1))
			break;
		l = &m->hash;
.
233,240c
	wunlock(&pg->ns);
	poperror();
	return nm->mountid;
}
.
224,231c
	if(m->mount && order == MAFTER) {
		for(f = m->mount; f->next; f = f->next)
			;
		f->next = nm;
	}
	else {
		nm->next = m->mount;
		m->mount = nm;
	}
.
221,222d
217,218c
	if(m->mount && order == MREPL) {
		mountfree(m->mount);
		m->mount = 0;
	}

	nm = newmount(m, new);
.
214,215d
208,212c

	if(m == 0) {
		m = newmnthead();
		m->from = old;
		incref(old);
		m->hash = *l;
		*l = m;
		if(order != MREPL) 
			m->mount = newmount(m, old);
.
196,206c

	l = &MOUNTH(pg, old);
	for(m = *l; m; m = m->hash) {
		if(eqchan(m->from, old, 1))
			break;
		l = &m->hash;
.
187,193c
	wlock(&pg->ns);
	if(waserror()) {
		wunlock(&pg->ns);
.
183,185d
180c

	order = flag&MORDER;

	if((old->qid.path&CHDIR)==0 && order != MREPL)
.
176c
	Mount *nm, *f;
	Mhead *m, **l;
	int order;
.
172,174d
147,168d
113a

.
99,106d
89,97c
		resrcwait("no chans\n");
.
81,87c
	for(;;) {
		lock(&chanalloc);
		if(c = chanalloc.free) {
			chanalloc.free = c->next;
			/* if closed before changed, this calls rooterror, a nop */
			c->type = 0;
			c->flag = 0;
			c->ref = 1;
			unlock(&chanalloc);
			c->dev = 0;
			c->offset = 0;
			c->mnt = 0;
			c->stream = 0;
			c->aux = 0;
			c->mntindex = 0;
			c->mchan = 0;
			c->mqid = (Qid){0, 0};
			return c;
		}
.
## diffname port/chan.c 1991/1105
## diff -e /n/bootesdump/1991/1011/sys/src/9/port/chan.c /n/bootesdump/1991/1105/sys/src/9/port/chan.c
595a
		poperror();
.
592a

		/*
		 *  protect against the open/create race. This is not a complete
		 *  fix. It just reduces the window.
		 */
		if(waserror()) {
			strcpy(createerr, u->error);
			nc = walk(c, elem, 1);
			if(nc == 0)
				errors(createerr);
			c = nc;
			omode |= OTRUNC;
			goto Open;
		}
.
436a
	char createerr[ERRLEN];
.
## diffname port/chan.c 1991/1107
## diff -e /n/bootesdump/1991/1105/sys/src/9/port/chan.c /n/bootesdump/1991/1107/sys/src/9/port/chan.c
653a
		if(elem >= eelem)
			error(Efilename);
.
649a
	char *eelem;

	eelem = elem+NAMELEN;
.
## diffname port/chan.c 1991/1126
## diff -e /n/bootesdump/1991/1107/sys/src/9/port/chan.c /n/bootesdump/1991/1126/sys/src/9/port/chan.c
412a
			poperror();
.
## diffname port/chan.c 1991/1206
## diff -e /n/bootesdump/1991/1126/sys/src/9/port/chan.c /n/bootesdump/1991/1206/sys/src/9/port/chan.c
665,666d
556c
		 * subsequent mounts to be attached to the original directory, not
.
85c
			/* if you get an error before associating with a dev,
			   close calls rootclose, a nop */
.
24,25d
## diffname port/chan.c 1992/0101
## diff -e /n/bootesdump/1991/1206/sys/src/9/port/chan.c /n/bootesdump/1992/0101/sys/src/9/port/chan.c
684,685c
		c = *(uchar*)name++;
		if(isfrog[c])
.
654c
		if(isfrog[*(uchar*)elem])
.
644a
/*0x80+	  NUL*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*BKS*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*DLE*/	1, 1, 1, 1, 1, 1, 1, 1,
	/*CAN*/	1, 1, 1, 1, 1, 1, 1, 1,
.
637c
char isfrog[256]={
.
## diffname port/chan.c 1992/0111
## diff -e /n/bootesdump/1992/0101/sys/src/9/port/chan.c /n/bootesdump/1992/0111/sys/src/9/port/chan.c
603c
				error(createerr);
.
257c
	error(Eunion);
.
226c
		error(Eunmount);
.
6c
#include	"../port/error.h"
.
## diffname port/chan.c 1992/0213
## diff -e /n/bootesdump/1992/0111/sys/src/9/port/chan.c /n/bootesdump/1992/0213/sys/src/9/port/chan.c
693d
691d
688,689c
		name += chartorune(&r, name);
		if(r<sizeof(isfrog) && isfrog[r])
.
677,686c
	end = utfrune(name, '/');
	if(end == 0)
		end = strchr(name, 0);
	w = end-name;
	if(w >= NAMELEN)
		error(Efilename);
	memmove(elem, name, w);
	elem[w] = 0;
.
673a
	Rune r;
.
672c
	int i, user, w;
.
## diffname port/chan.c 1992/0320
## diff -e /n/bootesdump/1992/0213/sys/src/9/port/chan.c /n/bootesdump/1992/0320/sys/src/9/port/chan.c
115,119c
		chanfree(c);
.
104a
chanfree(Chan *c)
{
	c->flag = CFREE;
	lock(&chanalloc);
	c->next = chanalloc.free;
	chanalloc.free = c;
	unlock(&chanalloc);
}

void
.
## diffname port/chan.c 1992/0321
## diff -e /n/bootesdump/1992/0320/sys/src/9/port/chan.c /n/bootesdump/1992/0321/sys/src/9/port/chan.c
2c
#include	"../port/lib.h"
.
## diffname port/chan.c 1992/0520
## diff -e /n/bootesdump/1992/0321/sys/src/9/port/chan.c /n/bootesdump/1992/0520/sys/src/9/port/chan.c
423a
	return 0;		/* not reached */
.
101a
	return 0;	/* not reached */
.
## diffname port/chan.c 1992/0619
## diff -e /n/bootesdump/1992/0520/sys/src/9/port/chan.c /n/bootesdump/1992/0619/sys/src/9/port/chan.c
255c
				free(m);
.
241c
		free(m);
.
181c
		m = smalloc(sizeof(Mhead));
.
94d
## diffname port/chan.c 1992/0620
## diff -e /n/bootesdump/1992/0619/sys/src/9/port/chan.c /n/bootesdump/1992/0620/sys/src/9/port/chan.c
101c

	/* if you get an error before associating with a dev,
	   close calls rootclose, a nop */
	c->type = 0;
	c->flag = 0;
	c->ref = 1;
	c->dev = 0;
	c->offset = 0;
	c->mnt = 0;
	c->stream = 0;
	c->aux = 0;
	c->mchan = 0;
	c->mqid = (Qid){0, 0};
	return c;
.
79,99c
	SET(nfid);

	lock(&chanalloc);
	c = chanalloc.free;
	if(c)
		chanalloc.free = c->next;
	else
		nfid = ++chanalloc.fid;
	unlock(&chanalloc);

	if(c == 0) {
		c = smalloc(sizeof(Chan));
		c->fid = nfid;
.
77a
	int nfid;
.
41,56d
10a
	int	fid;
.
8c
struct
{
.
## diffname port/chan.c 1992/0711
## diff -e /n/bootesdump/1992/0620/sys/src/9/port/chan.c /n/bootesdump/1992/0711/sys/src/9/port/chan.c
671,672c
	int w;
	char *end;
.
435c
	char *elem;
.
30,31d
## diffname port/chan.c 1992/0811
## diff -e /n/bootesdump/1992/0711/sys/src/9/port/chan.c /n/bootesdump/1992/0811/sys/src/9/port/chan.c
546a
		if(omode & ORCLOSE)
			c->flag |= CRCLOSE;
.
## diffname port/chan.c 1992/0825
## diff -e /n/bootesdump/1992/0811/sys/src/9/port/chan.c /n/bootesdump/1992/0825/sys/src/9/port/chan.c
475c
	}
	else {
.
461c
	}
	else
	if(name[0] == '#') {
.
455c
	if(name[0] == '/') {
.
314a
			}
.
309c
			for(t = f->mount; t; t = t->next) {
.
## diffname port/chan.c 1992/0919
## diff -e /n/bootesdump/1992/0825/sys/src/9/port/chan.c /n/bootesdump/1992/0919/sys/src/9/port/chan.c
648,651d
## diffname port/chan.c 1992/1217
## diff -e /n/bootesdump/1992/0919/sys/src/9/port/chan.c /n/bootesdump/1992/1217/sys/src/9/port/chan.c
471d
468c
		t = devno(r, 1);
.
466c
		name++;
		name += chartorune(&r, name);
		if(r == 'M')
.
431a
	Rune r;
.
54c
	for(i=0; i<devchar[i]; i++)
.
45c
	for(i=0; i<devchar[i]; i++)
.
## diffname port/chan.c 1993/0123
## diff -e /n/bootesdump/1992/1217/sys/src/9/port/chan.c /n/bootesdump/1993/0123/sys/src/9/port/chan.c
687c
	while(name < nend){
.
679,682c
	nend = utfrune(name, '/');
	if(nend == 0)
		nend = strchr(name, 0);
	w = nend-name;
.
674c
	char *nend;
.
## diffname port/chan.c 1993/0330
## diff -e /n/bootesdump/1993/0123/sys/src/9/port/chan.c /n/bootesdump/1993/0330/sys/src/9/port/chan.c
97a
	if(c->session){
		freesession(c->session);
		c->session = 0;
	}
.
## diffname port/chan.c 1993/0501
## diff -e /n/bootesdump/1993/0330/sys/src/9/port/chan.c /n/fornaxdump/1993/0501/sys/src/brazil/port/chan.c
691c
	while(name < end){
.
683,686c
	end = utfrune(name, '/');
	if(end == 0)
		end = strchr(name, 0);
	w = end-name;
.
678c
	char *end;
.
609c
			strcpy(createerr, up->error);
.
605,606c
		 * protect against the open/create race.
		 * This is not a complete fix. It just reduces the window.
.
588c
		nc = walk(cc, elem, 1);
		if(nc != 0) {
.
567c
		nc = walk(c, elem, 0);
		if(nc == 0)
.
563,565c
		 * When mounting on an already mounted upon directory,
		 * one wants subsequent mounts to be attached to the 
		 * original directory, not the replacement.
.
546,547c
		else {
			nc = walk(c, elem, mntok);
			if(nc == 0)
.
536c
		nc = walk(c, elem, 0);
		if(nc == 0)
.
524,525c
		else {
			nc = walk(c, elem, mntok);
			if(nc == 0)
.
517,519d
506,511c
	while(*name) {
		nc = walk(c, elem, mntok);
		if(nc == 0)
.
478,487c

		c = (*devtab[t].attach)(elem+n);
		name = skipslash(name);
		break;
	default:
		c = clone(up->dot, 0);
		name = skipslash(name);
.
471,474c
		elem[0] = 0;
		n = 0;
		while(*name && (*name != '/' || n < 2))
			elem[n++] = *name++;
		elem[n] = '\0';
		n = chartorune(&r, elem+1)+1;
		if(r == 'M') {
			name = skipslash(name);
			if(*name)
				error(Eperm);
			return mchan(elem+n);
		}
.
467,469c
		break;
	case '#':
.
461,465c
	switch(name[0]) {
	case '/':
		c = clone(up->slash, 0);
.
458c
	elem = up->elem;
.
452c
		while(vmemchr(p, 0, t) == 0) {
.
445,449c
	if(!((ulong)name & KZERO)) {
.
439a
	int t, n;
	int mntok, isdot;
	Chan *c, *nc, *cc;
.
437d
434,435d
421a
Chan*
mchan(char *id)
{
	Chan *c;
	Pgrp *pg;
	Mount *t;
	int mdev;
	ulong mountid;
	Mhead **h, **he, *f;

	mountid = strtoul(id, 0, 0);
	mdev = devno('M', 0);

	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) {
			for(t = f->mount; t; t = t->next) {
				c = t->to;
				if(c->type == mdev && c->mntptr->id == mountid) {
					c = c->mntptr->c;
					incref(c);
					runlock(&pg->ns);
					poperror();
					return c;
				}
			}
		}
	}
	error(Enonexist);
	return 0;
}

.
402c
	pg = up->pgrp;
.
388a
	close(ac);
.
387c
		c = domount(c);
		poperror();
.
375,385c
	if(c == 0)
		return 0;

	if(dotdot)
		c = undomount(c);

	c->mnt = 0;
	if(domnt) {
		if(waserror()) {
			close(c);
			nexterror();
.
357c
	c = 0;
	pg = up->pgrp;

.
339,341c
	if(name[0] == '.' && name[1] == '.' && name[2] == '\0') {
.
335c
	if(name[0] == '\0')
.
331c
	Chan *c;
.
303c
	pg = up->pgrp;
.
284a
			nc->xmnt = nc->mnt;
.
273c
	pg = up->pgrp;
.
214c
	pg = up->pgrp;
.
188c
	nm = newmount(m, new, flag, spec);


.
180c
			m->mount = newmount(m, old, 0, 0);
.
159c
	pg = up->pgrp;
.
149d
146a
	int order;
.
144c
mount(Chan *new, Chan *old, int flag, char *spec)
.
121a
	chanfree(c);
}
.
120a

/* ASSERT */
if(c->path && c->path->ref == 0) {
	char buf[64];
	ptpath(c->path, buf, sizeof(buf));
	print(">>%s %c %d %lux.%lux\n",
	buf, devchar[c->type], c->dev, c->qid.path, c->qid.vers);
.
114,119c
	if(decref(c))
		return;

	if(!waserror()) {
		(*devtab[c->type].close)(c);
		poperror();
.
111c
	if(c->flag&CFREE)
.
101a

	/*
	 * Channel can be closed before a path is created or the last
	 * channel in a mount which has already cleared its pt names
	 */
	if(c->path)
		decref(c->path);

.
97a

.
89a
	c->path = 0;
.
76c
		lock(&chanalloc);
		c->fid = ++chanalloc.fid;
		c->link = chanalloc.list;
		chanalloc.list = c;
		unlock(&chanalloc);
.
70,71d
68c
	if(c != 0)
.
64,65d
62d
40a
chanrec(Mnt *m)
{
	Chan *c;

	lock(&chanalloc);
	for(c = chanalloc.list; c; c = c->link)
		if(c->mntptr == m)
			c->flag |= CRECOV;
	unlock(&chanalloc);
}

void
.
12a
	Chan	*free;
	Chan	*list;
.
11d
## diffname port/chan.c 1993/0511
## diff -e /n/fornaxdump/1993/0501/sys/src/brazil/port/chan.c /n/fornaxdump/1993/0511/sys/src/brazil/port/chan.c
99d
## diffname port/chan.c 1993/0526
## diff -e /n/fornaxdump/1993/0511/sys/src/brazil/port/chan.c /n/fornaxdump/1993/0526/sys/src/brazil/port/chan.c
67c
	for(i=0; devchar[i]; i++)
.
58c
	for(i=0; devchar[i]; i++)
.
## diffname port/chan.c 1993/1007
## diff -e /n/fornaxdump/1993/0526/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1007/sys/src/brazil/port/chan.c
595a
		nc = walk(c, elem, mntok);
		if(nc == 0)
			error(Enonexist);
		c = nc;
.
590,594c
			break;
.
588c
		if(isdot) {
.
586c
	switch(amode) {
.
## diffname port/chan.c 1993/1013
## diff -e /n/fornaxdump/1993/1007/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1013/sys/src/brazil/port/chan.c
101a
	c->mcp = 0;
.
## diffname port/chan.c 1993/1015
## diff -e /n/fornaxdump/1993/1013/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1015/sys/src/brazil/port/chan.c
144,150d
## diffname port/chan.c 1993/1017
## diff -e /n/fornaxdump/1993/1015/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1017/sys/src/brazil/port/chan.c
617a
		if(omode == OEXEC)
			c->flag |= CTEXT;
.
## diffname port/chan.c 1993/1018
## diff -e /n/fornaxdump/1993/1017/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1018/sys/src/brazil/port/chan.c
619c
			c->flag &= ~CCACHE;
	
		c = (*devtab[c->type].open)(c, omode);

.
616,617c
		saveregisters();

.
## diffname port/chan.c 1993/1111
## diff -e /n/fornaxdump/1993/1018/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1111/sys/src/brazil/port/chan.c
266c
		if(eqchan(f->to, mounted, 1) || eqchan(f->to->mchan, mounted, 1)) {
.
## diffname port/chan.c 1993/1114
## diff -e /n/fornaxdump/1993/1111/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1114/sys/src/brazil/port/chan.c
541a
			name = skipslash(name);
.
539,540c
			if(amode != Aopen || omode != ORDWR)
.
## diffname port/chan.c 1993/1115
## diff -e /n/fornaxdump/1993/1114/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1115/sys/src/brazil/port/chan.c
224c
		for(f = nm; f->next; f = f->next)
			;
		f->next = m->mount;
.
214d
212a
	if(new->mnt != 0) {
		h = &nm->next;
		for(um = new->mnt->next; um; um = um->next) {
			flg = um->flag;
			if(flg == 0)
				flg = MAFTER;
			f = newmount(m, um->to, flg, um->spec);
			*h = f;
			h = &f->next;
		}
	}
.
173a
	Mount *nm, *f, *um, **h;
.
171,172c
	int order, flg;
.
## diffname port/chan.c 1993/1121
## diff -e /n/fornaxdump/1993/1115/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1121/sys/src/brazil/port/chan.c
553c
			skipslash(name);
.
## diffname port/chan.c 1993/1216
## diff -e /n/fornaxdump/1993/1121/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1216/sys/src/brazil/port/chan.c
222a
	}

	if(m->mount && order == MREPL) {
		mountfree(m->mount);
		m->mount = 0;
.
216,218d
213a
		/*
		 *  copy a union when binding it onto a directory
		 */
		flg = order;
		if(order == MREPL)
			flg = MAFTER;
.
207,211d
## diffname port/chan.c 1993/1217
## diff -e /n/fornaxdump/1993/1216/sys/src/brazil/port/chan.c /n/fornaxdump/1993/1217/sys/src/brazil/port/chan.c
202a

		/*
		 *  if this is a union mount, add the old
		 *  node to the mount chain.
		 */
.
197a
		/*
		 *  nothing mounted here yet.  create a mount
		 *  head and add to the hash table.
		 */
.
## diffname port/chan.c 1994/0115
## diff -e /n/fornaxdump/1993/1217/sys/src/brazil/port/chan.c /n/fornaxdump/1994/0115/sys/src/brazil/port/chan.c
289a
		/* BUG: Needs to be 2 pass */
.
## diffname port/chan.c 1994/0509
## diff -e /n/fornaxdump/1994/0115/sys/src/brazil/port/chan.c /n/fornaxdump/1994/0509/sys/src/brazil/port/chan.c
291c
		if(eqchan(f->to, mounted, 1) ||
		  (f->to->mchan && eqchan(f->to->mchan, mounted, 1))) {
.
## diffname port/chan.c 1994/0812
## diff -e /n/fornaxdump/1994/0509/sys/src/brazil/port/chan.c /n/fornaxdump/1994/0812/sys/src/brazil/port/chan.c
133c
	if(c == 0 || (c->flag&CFREE))
.
## diffname port/chan.c 1994/0813
## diff -e /n/fornaxdump/1994/0812/sys/src/brazil/port/chan.c /n/fornaxdump/1994/0813/sys/src/brazil/port/chan.c
133c
	if(c->flag&CFREE)
.
## diffname port/chan.c 1994/1212
## diff -e /n/fornaxdump/1994/0813/sys/src/brazil/port/chan.c /n/fornaxdump/1994/1212/sys/src/brazil/port/chan.c
565,568c
			c = mchan(elem+n);
			name = skipslash(name);
			break;
.
503,504c
					c = clone(c, 0);
.
## diffname port/chan.c 1995/0208
## diff -e /n/fornaxdump/1994/1212/sys/src/brazil/port/chan.c /n/fornaxdump/1995/0208/sys/src/brazil/port/chan.c
564,565c
			if(elem[n] == 'c') {
				c = mchan(elem+n+1, 0);
				name = skipslash(name);
				if(*name)
					error(Efilename);
				return c;
			}
			else {
				c = mchan(elem+n, 1);
				name = skipslash(name);
			}
.
503c
					if(walkname == 0) {
						c = c->mntptr->c;
						incref(c);
					}
					else
						c = clone(c, 0);
.
478c
mchan(char *id, int walkname)
.
## diffname port/chan.c 1996/0730
## diff -e /n/fornaxdump/1995/0208/sys/src/brazil/port/chan.c /n/fornaxdump/1996/0730/sys/src/brazil/port/chan.c
727a
		if(omode & ORCLOSE)
			c->flag |= CRCLOSE;
.
## diffname port/chan.c 1997/0327
## diff -e /n/fornaxdump/1996/0730/sys/src/brazil/port/chan.c /n/emeliedump/1997/0327/sys/src/brazil/port/chan.c
725c
		devtab[c->type]->create(c, elem, omode, perm);
.
703c
		cclose(cc);
.
698c
			cclose(c);
.
691c
			cclose(cc);
.
689c
		cc = cclone(c, 0);
.
659c
		c = devtab[c->type]->open(c, omode);
.
597c
		cclose(c);
.
590c
		c = cclone(up->dot, 0);
.
586c
		c = devtab[t]->attach(elem+n);
.
557c
		c = cclone(up->slash, 0);
.
508c
						c = cclone(c, 0);
.
474c
	return 0;
.
469c
			cclose(c);
.
465c
			nc = cclone(f->to, 0);
.
443c
	cclose(ac);
.
437c
			cclose(c);
.
422c
		cclose(c);
.
419,420c
		c = cclone(f->to, 0);
		if(devtab[c->type]->walk(c, name) != 0)
.
415c
			cclose(c);
.
397c
	if(devtab[ac->type]->walk(ac, name) != 0) {
.
368,369c
					cclose(c);
					c = cclone(t->head->from, 0);
.
339c
			cclose(c);
.
335c
			nc = cclone(m->mount->to, 0);
.
315c
	return devtab[c->type]->clone(c, nc);
.
313c
cclone(Chan *c, Chan *nc)
.
299c
				cclose(m->from);
.
283c
		cclose(m->from);
.
258c
cunmount(Chan *mnt, Chan *mounted)
.
168c
cmount(Chan *new, Chan *old, int flag, char *spec)
.
140c
		devtab[c->type]->close(c);
.
134,135c
		panic("cclose %lux", getcallerpc(c));
.
131c
cclose(Chan *c)
.
68c
		devtab[i]->init();
.
59c
		devtab[i]->reset();
.
## diffname port/chan.c 1997/0408
## diff -e /n/emeliedump/1997/0327/sys/src/brazil/port/chan.c /n/emeliedump/1997/0408/sys/src/brazil/port/chan.c
67c
	for(i=0; devtab[i] != nil; i++)
.
58c
	for(i=0; devtab[i] != nil; i++)
.
## diffname port/chan.c 1997/0813
## diff -e /n/emeliedump/1997/0408/sys/src/brazil/port/chan.c /n/emeliedump/1997/0813/sys/src/brazil/port/chan.c
418a
		c->flag &= ~CCREATE;	/* not inherited through a walk */
.
395a
	ac->flag &= ~CCREATE;	/* not inherited through a walk */
.
## diffname port/chan.c 1997/1121
## diff -e /n/emeliedump/1997/0813/sys/src/brazil/port/chan.c /n/emeliedump/1997/1121/sys/src/brazil/port/chan.c
368c
					c = nc;
.
366a
					nc = cclone(t->head->from, 0);
.
353a
	Mhead **h, **he, *f;
.
352d
350a
	Chan *nc;
.
## diffname port/chan.c 1997/1208
## diff -e /n/emeliedump/1997/1121/sys/src/brazil/port/chan.c /n/emeliedump/1997/1208/sys/src/brazil/port/chan.c
106a
int
okchan1(Chan *c)
{
	if(c->type > 64)
		return 0;
	if((ulong)(c->next) & 3)
		return 0;
	if((ulong)(c->link) & 3)
		return 0;
	if((ulong)(c->path) & 3)
		return 0;
	if((ulong)(c->mnt) & 3)
		return 0;
	if((ulong)(c->xmnt) & 3)
		return 0;
	if((ulong)(c->mcp) & 3)
		return 0;
	if((ulong)(c->mchan) & 3)
		return 0;
	if((ulong)(c->session) & 3)
		return 0;
	return 1;
}

void
okchan(char *msg, int n)
{
	int s;
	Chan *c;

	return;
	s = splhi();
	for(c = chanalloc.list; c; c = c->link)
		if(!okchan1(c)){
			spllo();
			print("okchan: %s (%d=#%.8lux)\n", msg, n, n);
			panic("okchan");
		}
	splx(s);
}

.
## diffname port/chan.c 1997/1210
## diff -e /n/emeliedump/1997/1208/sys/src/brazil/port/chan.c /n/emeliedump/1997/1210/sys/src/brazil/port/chan.c
140,144c
		okchan1(c, msg, n);
.
137d
110,128c
	int i, bad;

	bad = 0;
	if(c->type > 64){
		print("bad type %d\n", c->type);
		bad = 1;
	}
	if((ulong)(c->next) & 3){
		print("bad next %.8lux\n", c->next);
		bad = 1;
	}
	if((ulong)(c->link) & 3){
		print("bad link %.8lux\n", c->link);
		bad = 1;
	}
	if((ulong)(c->path) & 3){
		print("bad path %.8lux\n", c->path);
		bad = 1;
	}
	if((ulong)(c->mnt) & 3){
		print("bad mnt %.8lux\n", c->mnt);
		bad = 1;
	}
	if((ulong)(c->xmnt) & 3){
		print("bad xmnt %.8lux\n", c->xmnt);
		bad = 1;
	}
	if((ulong)(c->mcp) & 3){
		print("bad mcp %.8lux\n", c->mcp);
		bad = 1;
	}
	if((ulong)(c->mchan) & 3){
		print("bad mchan %.8lux\n", c->mchan);
		bad = 1;
	}
	if((ulong)(c->session) & 3){
		print("bad session %.8lux\n", c->session);
		bad = 1;
	}
	if(!bad)
		return;

	print("okchan: %s (%d=#%.8lux)\n", msg, n, n);
	for(i=0; i<16; i++){
		print("%d=%.8lux\n", i, ((ulong*)c)[i]);
		if((i&7) == 7)
			print("\n");
	}
	for(;;);
.
107,108c
void
okchan1(Chan *c, char *msg, int n)
.
## diffname port/chan.c 1997/1211
## diff -e /n/emeliedump/1997/1210/sys/src/brazil/port/chan.c /n/emeliedump/1997/1211/sys/src/brazil/port/chan.c
166a
	return;
.
## diffname port/chan.c 1998/0221
## diff -e /n/emeliedump/1997/1211/sys/src/brazil/port/chan.c /n/emeliedump/1998/0221/sys/src/brazil/port/chan.c
108,174d
## diffname port/chan.c 1998/0224
## diff -e /n/emeliedump/1998/0221/sys/src/brazil/port/chan.c /n/emeliedump/1998/0224/sys/src/brazil/port/chan.c
724d
721,722c
			if(walk(&c, elem, 1) < 0)
.
702c
			c = cc;
.
698,699c
		if(walk(&cc, elem, 1) == 0){
.
679d
676,677c
		if(walk(&c, elem, 0) < 0)
.
653d
650,651c
			if(walk(&c, elem, mntok) < 0)
.
641d
638,639c
		if(walk(&c, elem, 0) < 0)
.
630d
627,628c
		if(walk(&c, elem, mntok) < 0)
.
617d
614,615c
		if(walk(&c, elem, mntok) < 0)
.
540c
	Chan *c, *cc;
.
447c
	*cp = c;
	return 0;	
.
431,432c
	if(c == nil)
		return -1;
.
426c
		c = nil;
.
410c
	c = nil;
.
407,408c
	if(ac->mnt == nil) 
		return -1;
.
403,404c
			*cp = domount(*cp);
		return 0;
.
401c
			*cp = undomount(*cp);
.
394c
		*cp = ac = undomount(ac);
.
390c
		return 0;
.
388a
	ac = *cp;

.
385c
	Chan *c, *ac;
.
381,382c
int
walk(Chan **cp, char *name, int domnt)
.
## diffname port/chan.c 1998/0416
## diff -e /n/emeliedump/1998/0224/sys/src/brazil/port/chan.c /n/emeliedump/1998/0416/sys/src/brazil/port/chan.c
122a
	} 
.
121c
	if(c->path) {
		if (c->path->ref <= 0) {
			char buf[100]; 
			ptpath(c->path, buf, sizeof(buf)); 
			print("decref %s\n", buf); 
		} 
.
## diffname port/chan.c 1998/0512
## diff -e /n/emeliedump/1998/0416/sys/src/brazil/port/chan.c /n/emeliedump/1998/0512/sys/src/brazil/port/chan.c
674c
		 * one wants subsequent mounts to be attached to the
.
662c

.
456c
	return 0;
.
415c
	if(ac->mnt == nil)
.
345,346c
			c = nc;
			break;
.
217c
		if(order != MREPL)
.
128c
	}
.
123,126c
			char buf[100];
			ptpath(c->path, buf, sizeof(buf));
			print("decref %s\n", buf);
		}
.
35c
	if(x < 0)
.
## diffname port/chan.c 1998/0813
## diff -e /n/emeliedump/1998/0512/sys/src/brazil/port/chan.c /n/emeliedump/1998/0813/sys/src/brazil/port/chan.c
606a
	c->mnt = nil;
.
## diffname port/chan.c 1998/0829
## diff -e /n/emeliedump/1998/0813/sys/src/brazil/port/chan.c /n/emeliedump/1998/0829/sys/src/brazil/port/chan.c
814a
}

void
putmhead(Mhead *m)
{
	if(decref(m) == 0)
		free(m);
.
711c
		if(c->mh != nil && !(c->flag&CCREATE))
.
607d
478,479c
			if(nc->mh != nil)
				putmhead(nc->mh);
			nc->mh = c->mh;
			incref(c->mh);
			runlock(&c->mh->lock);
.
475c
	for(f = c->mh->mount; f; f = f->next) {
.
472c
		runlock(&c->mh->lock);
.
469,470c
	rlock(&c->mh->lock);
.
465d
445c
	if(c->mh){
		putmhead(c->mh);
		c->mh = nil;
	}
.
437c
	runlock(&ac->mh->lock);
.
428c
	for(f = ac->mh->mount; f; f = f->next) {
.
423c
		runlock(&ac->mh->lock);
.
421c
	rlock(&ac->mh->lock);
.
419d
415c
	if(ac->mh == nil)
.
390d
349d
347a
		runlock(&m->lock);
	}
.
346c
			poperror();
			runlock(&m->lock);
			return c;
.
341,343c
			if(nc->mh != nil)
				putmhead(nc->mh);
			nc->mh = m;
			nc->xmh = m;
			incref(m);
.
339a
			if(waserror()) {
				runlock(&m->lock);
				nexterror();
			}
			runlock(&pg->ns);
.
338c
	for(m = MOUNTH(pg, c); m; m = m->hash){
		rlock(&m->lock);
.
336d
332,334c
	if(c->mh){
		putmhead(c->mh);
		c->mh = 0;
.
313c
	wunlock(&m->lock);
.
308c
			wunlock(&m->lock);
.
305c
				wunlock(&m->lock);
				putmhead(m);
.
301c
			if(m->mount == nil) {
.
291a
	wunlock(&pg->ns);
.
289c
		wunlock(&m->lock);
		putmhead(m);
.
287a
		m->mount = nil;
.
283a
	wlock(&m->lock);
.
257c
	wunlock(&m->lock);
.
230c
		um = new->mh->mount;
		for(um = um->next; um; um = um->next) {
.
222c
	if(new->mh != nil && new->mh->mount != nil) {
.
219a
	wlock(&m->lock);
	if(waserror()){
		wunlock(&m->lock);
		nexterror();
	}
	wunlock(&pg->ns);
.
207a
		m->ref = 1;
.
190,193d
116a
	if(c->mh != nil){
		putmhead(c->mh);
		c->mh = nil;
	}

.
98c
	c->mh = 0;
	c->xmh = 0;
	c->uri = 0;
.
## diffname port/chan.c 1999/0122
## diff -e /n/emeliedump/1998/0829/sys/src/brazil/port/chan.c /n/emeliedump/1999/0122/sys/src/brazil/port/chan.c
752c
		devtab[c->type]->create(c, elem, omode&~OCEXEC, perm);
.
691c
		c = devtab[c->type]->open(c, omode&~OCEXEC);
.
## diffname port/chan.c 1999/0323
## diff -e /n/emeliedump/1999/0122/sys/src/brazil/port/chan.c /n/emeliedump/1999/0323/sys/src/brazil/port/chan.c
788c
/*	[' ']	1,	rob - let's try this out */
.
## diffname port/chan.c 1999/0501
## diff -e /n/emeliedump/1999/0323/sys/src/brazil/port/chan.c /n/emeliedump/1999/0501/sys/src/brazil/port/chan.c
147c
		panic("cclose %lux", getcallerpc(&c));
.
## diffname port/chan.c 1999/0629
## diff -e /n/emeliedump/1999/0501/sys/src/brazil/port/chan.c /n/emeliedump/1999/0629/sys/src/brazil/port/chan.c
762a

	poperror();

	/* peculiar workaround for #/ */
	if(newname){
		if(cname->s[0]=='#' && cname->s[1]=='/')
			cleanname(cname, 2);
		else
			cleanname(cname, 0);
		cnameclose(c->name);
		c->name = cname;
	}else
		cnameclose(cname);

.
691a
		if(cc != c)
			newname = 0;
.
690a
		cc = c;
.
629a
		cname = newcname(up->dot->name->s);
		cname = addelem(cname, name);
.
613a
				poperror();
				cnameclose(cname);
.
600a
		cname = newcname(name);	/* save this before advancing */
.
598a
		c = cclone(up->slash, 0);
.
597c
		cname = newcname(name);	/* save this before advancing */
.
591a
	newname = 1;
	cname = nil;
	if(waserror()){
		cnameclose(cname);
		nexterror();
	}

.
575c
	Cname *cname;
	int t, n, newname;
.
565a
 * In place, rewrite name to compress multiple /, eliminate ., and process ..
 */
void
cleanname(Cname *n, int offset)
{
	char *p, *q, *dotdot, *name;
	int rooted;

	name = n->s+offset;
	rooted = name[0] == '/';

	/*
	 * invariants:
	 *	p points at beginning of path element we're considering.
	 *	q points just past the last path element we wrote (no slash).
	 *	dotdot points just past the point where .. cannot backtrack
	 *		any further (no slash).
	 */
	p = q = dotdot = name+rooted;
	while(*p) {
		if(p[0] == '/')	/* null element */
			p++;
		else if(p[0] == '.' && SEP(p[1]))
			p += 1;	/* don't count the separator in case it is nul */
		else if(p[0] == '.' && p[1] == '.' && SEP(p[2])) {
			p += 2;
			if(q > dotdot) {	/* can backtrack */
				while(--q > dotdot && *q != '/')
					;
			} else if(!rooted) {	/* ``/..'' ≡ ``/'', but ``./../'' ≡ ``..'' */
				if(q != name)
					*q++ = '/';
				*q++ = '.';
				*q++ = '.';
				dotdot = q;
			}
		} else {	/* real path element */
			if(q != name+rooted)
				*q++ = '/';
			while((*q = *p) != '/' && *q != 0)
				p++, q++;
		}
	}
	if(q == name)	/* empty string is really ``.'' */
		*q++ = '.';
	*q = 0;
	n->len = (q-name) + offset;
}

/*
.
413a
walkname(Chan **cp, char *name, int domnt)
{
	Chan *c;

	if(walk(cp, name, domnt) < 0)
		return -1;
	c = *cp;
	if(c->name == nil)
		c->name = newcname(name);
	else
		c->name = addelem(c->name, name);
	return 0;
}

int
.
336c
	nc = devtab[c->type]->clone(c, nc);
	if(nc != nil){
		nc->name = c->name;
		if(c->name)
			incref(c->name);
	}
	return nc;
.
124,135c
	cnameclose(c->name);
.
109a
cnameclose(Cname *n)
{
	if(n == 0)
		return;
	if(decref(n))
		return;
	decref(&ncname);
	free(n->s);
	free(n);
}

Cname*
addelem(Cname *n, char *s)
{
	int i, a;
	char *t;
	Cname *new;

	if(n->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;
	}
	n->s[n->len++] = '/';
	memmove(n->s+n->len, s, i+1);
	n->len += i;
	return n;
}

void
.
108a
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 = 1;
	incref(&ncname);
	return n;
}

.
105a
	c->name = 0;
.
103d
15a
#define SEP(c) ((c) == 0 || (c) == '/')

.
7a
enum
{
	CNAMESLOP	= 20
};

.
## diffname port/chan.c 1999/0630
## diff -e /n/emeliedump/1999/0629/sys/src/brazil/port/chan.c /n/emeliedump/1999/0630/sys/src/brazil/port/chan.c
162c
	if(n->len+1+i+1 > n->alen){
.
## diffname port/chan.c 1999/0716
## diff -e /n/emeliedump/1999/0630/sys/src/brazil/port/chan.c /n/emeliedump/1999/0716/sys/src/brazil/port/chan.c
915c
			cleancname(cname, 0);
.
913c
			cleancname(cname, 1);
.
688c
	*q = '\0';
.
672c
			} else if(!rooted) {	/* /.. is / but ./../ is .. */
.
646c
cleancname(Cname *n, int offset)
.
## diffname port/chan.c 1999/0718
## diff -e /n/emeliedump/1999/0716/sys/src/brazil/port/chan.c /n/emeliedump/1999/0718/sys/src/brazil/port/chan.c
959c
			if(!slashok || *elem!='/')
				error(Ebadchar);
.
952c
nameok(char *elem, int slashok)
.
868c
		nameok(elem, 0);
.
## diffname port/chan.c 1999/0811
## diff -e /n/emeliedump/1999/0718/sys/src/brazil/port/chan.c /n/emeliedump/1999/0811/sys/src/brazil/port/chan.c
513c
			*cp = domount(c);
.
510,511c
		/* walk succeeded: update name associated with *cp (ac) */
		c = *cp;
		if(c->name == nil)
			c->name = newcname(name);
		else
			c->name = addelem(c->name, name);
		
		if(dotdot){
			cleancname(c->name, c->name->s[0]=='#');	/* could be cheaper */
			*cp = undomount(c);
		}
.
476,490d
462a
					/* don't need to update nc->name because c->name is same! */
.
461a
					/*
					 * 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, c->name->s) != 0)
						continue;
.
428a
			cnameclose(nc->name);
			nc->name = c->name;
			incref(c->name);
.
21a
void cleancname(Cname*, int);
.
## diffname port/chan.c 1999/0820
## diff -e /n/emeliedump/1999/0811/sys/src/brazil/port/chan.c /n/emeliedump/1999/0820/sys/src/brazil/port/chan.c
520c
			*cp = domount(*cp);
.
## diffname port/chan.c 1999/1105
## diff -e /n/emeliedump/1999/0820/sys/src/brazil/port/chan.c /n/emeliedump/1999/1105/sys/src/9/port/chan.c
50,61d
## diffname port/chan.c 1999/1224
## diff -e /n/emeliedump/1999/1105/sys/src/9/port/chan.c /n/emeliedump/1999/1224/sys/src/9/port/chan.c
737a
		}
.
736c
		while(*name && (*name != '/' || n < 2)){
			if(n >= NAMELEN-1)
				error(Efilename);
.
554a

	if(domnt)
		*cp = domount(c);
.
545,552c

	/* replace c->name by ac->name */
	cnameclose(c->name);
	c->name = ac->name;
	if(ac->name)
		incref(ac->name);
	c = updatecname(c, name, dotdot);
.
538,540d
497,506c
		*cp = updatecname(*cp, name, dotdot);
.
475a
Chan *
updatecname(Chan *c, char *name, int dotdot)
{
	if(c->name == nil)
		c->name = newcname(name);
	else
		c->name = addelem(c->name, name);
	
	if(dotdot){
		cleancname(c->name, c->name->s[0]=='#');	/* could be cheaper */
		c = undomount(c);
	}
	return c;
}

.
159c
	if(n->len>0 && n->s[n->len-1]!='/' && s[0]!='/')	/* don't insert extra slash if one is present */
		n->s[n->len++] = '/';
.
## diffname port/chan.c 1999/1230
## diff -e /n/emeliedump/1999/1224/sys/src/9/port/chan.c /n/emeliedump/1999/1230/sys/src/9/port/chan.c
916,919c
		cleancname(cname);
.
914d
655,690c
		/*
		 * 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);
.
652,653c
	if(n->s[0] == '#'){
		p = strchr(n->s, '/');
		if(p == nil)
			return;
		cleanname(p);
.
649,650c
	char *p;
.
647c
cleancname(Cname *n)
.
486c
		cleancname(c->name);	/* could be cheaper */
.
22c
void cleancname(Cname*);
.
## diffname port/chan.c 2000/0322
## diff -e /n/emeliedump/1999/1230/sys/src/9/port/chan.c /n/emeliedump/2000/0322/sys/src/9/port/chan.c
712a
		/*
		 *  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)
		 */
		if(up->pgrp->noattach)
		if(strchr("|decp", name[1]) == 0)
			error(Enoattach);
.
## diffname port/chan.c 2000/0326
## diff -e /n/emeliedump/2000/0322/sys/src/9/port/chan.c /n/emeliedump/2000/0326/sys/src/9/port/chan.c
723a
		 *  all are ASCII, so it's safe to use strchr to check.
.
## diffname port/chan.c 2000/0330
## diff -e /n/emeliedump/2000/0326/sys/src/9/port/chan.c /n/emeliedump/2000/0330/sys/src/9/port/chan.c
740,755c
		/* actually / is caught by parsing earlier */
		if(utfrune("M", r))
			error(Enoattach);
		if(up->pgrp->noattach && utfrune("|decp", r))
			error(Enoattach);
.
726,738d
724d
712a
		cname = newcname(name);	/* save this before advancing */
		mntok = 0;
		elem[0] = 0;
		n = 0;
		while(*name && (*name != '/' || n < 2)){
			if(n >= NAMELEN-1)
				error(Efilename);
			elem[n++] = *name++;
		}
		elem[n] = '\0';
.
595,637d
## diffname port/chan.c 2000/0904
## diff -e /n/emeliedump/2000/0330/sys/src/9/port/chan.c /n/emeliedump/2000/0904/sys/src/9/port/chan.c
644c
	if(((ulong)name & KZERO) != KZERO) {
.
## diffname port/chan.c 2000/1124
## diff -e /n/emeliedump/2000/0904/sys/src/9/port/chan.c /n/emeliedump/2000/1124/sys/src/9/port/chan.c
696c
		if(up->pgrp->noattach && utfrune("|decp", r)==nil)
.
## diffname port/chan.c 2001/0214
## diff -e /n/emeliedump/2000/1124/sys/src/9/port/chan.c /n/emeliedump/2001/0214/sys/src/9/port/chan.c
364d
## diffname port/chan.c 2001/0424
## diff -e /n/emeliedump/2001/0214/sys/src/9/port/chan.c /n/emeliedump/2001/0424/sys/src/9/port/chan.c
666a
		if(*name == 0)
			isdot = 1;
.
## diffname port/chan.c 2001/0502
## diff -e /n/emeliedump/2001/0424/sys/src/9/port/chan.c /n/emeliedump/2001/0502/sys/src/9/port/chan.c
202a
	poperror();
.
201a
	devtab[c->type]->close(c);
.
197,199c
	if(waserror()){
		print("cclose error: type %C; error %s\n", devtab[c->type]->dc, up!=nil? up->error : "no user"); //BUG
		return;
.
## diffname port/chan.c 2001/0503
## diff -e /n/emeliedump/2001/0502/sys/src/9/port/chan.c /n/emeliedump/2001/0503/sys/src/9/port/chan.c
204a
	chanfree(c);
.
203d
198a
		chanfree(c);
.
## diffname port/chan.c 2001/0504
## diff -e /n/emeliedump/2001/0503/sys/src/9/port/chan.c /n/emeliedump/2001/0504/sys/src/9/port/chan.c
198c
//		print("cclose error: type %C; error %s\n", devtab[c->type]->dc, up!=nil? up->error : "no user");
.
## diffname port/chan.c 2001/0527
## diff -e /n/emeliedump/2001/0504/sys/src/9/port/chan.c /n/emeliedump/2001/0527/sys/src/9/port/chan.c
944a
	}
.
943c
	if(m && decref(m) == 0){
decref(&mheadcounter);
		m->mount = (Mount*)0xCafeBeef;
.
939a
/*
 * 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.
 */
.
935c
	if(c->qid.type & QTDIR)
.
929d
914,927c
	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!='/')
					error(Ebadchar);
			name++;
		}
.
910,911c
	char *p, *ename;
	uint t;
	int c;
.
907,908c
void
validname(char *name, int slashok)
.
905c
 * 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.
.
888,903d
883d
871c
	if(*name=='.' && (name[1]=='\0' || name[1]=='/')){
.
863c
 * name is valid. skip leading / and ./ and trailing .
.
851,858c
	/* 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);
.
837,843c
		panic("namec: not reached");				
.
826,833c
			/*
			 * 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);

			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;
			break;
		}else{		/* create failed */
			cclose(cnew);
			if(m)
				putmhead(m);
			if(omode & OEXCL)
				nexterror();
			if(walk(&c, e.elems+e.nelems-1, 1, nomount) < 0)
				nexterror();
.
823,824c
		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);
			}
.
821c
		 * 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.
.
817,818d
804,813c
		e.nelems++;
		if(walk(&c, e.elems+e.nelems-1, 1, nomount) == 0){
			if(omode&OEXCL){
				cclose(c);
				error(Eexist);
			}
.
799,802c
		 * 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.
.
795,797d
790,791d
788c
		 * original directory, not the replacement.  Don't domount.
.
783a
	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;

.
775,776d
773d
767c
		/* save the name; domount might change c */
		cname = c->name;
		incref(cname);
		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;

		if(amode == Aremove){
			putmhead(m);
			break;
		}

if(c->umh != nil){
	print("cunique umh\n");
	putmhead(c->umh);
}
		c->umh = m;

		/* save registers else error() in open has wrong value of c saved */
.
760,765d
748,758c
	case Aremove:
.
740,745c
		if(!nomount)
			domount(&c, nil);
.
738c
	if(walk(&c, e.elems, e.nelems, nomount) < 0)
		error(Enonexist);

	switch(amode){
.
732,735c
	/*
	 * On create, don't try to walk the last path element just yet.
	 */
	if(amode == Acreate){
		if(e.nelems == 0)
			error(Eisdir);
		e.nelems--;
.
729,730c
	parsename(name, &e);
.
726,727c
	 * Build a list of elements in the path.
.
723,724d
719a
		free(e.name);
		free(e.elems);
//dumpmount();
.
718a
		if(strcmp(up->error, Enonexist) == 0){
			if(strlen(aname) < ERRMAX/3 || (name=strrchr(aname, '/'))==nil || name==aname)
				snprint(up->error, sizeof up->error, "\"%s\" does not exist", aname);
			else
				snprint(up->error, sizeof up->error, "file \"...%s\" does not exist", name);
		}
.
717a
	e.name = nil;
	e.elems = nil;
.
714,715c
		break;
.
710,712c
		c = up->dot;
		incref(c);
.
708a

.
705,707c
		c = devtab[t]->attach(up->genbuf+n);
.
696c
		n = chartorune(&r, up->genbuf+1)+1;
.
683c
		up->genbuf[n] = '\0';
.
681c
			up->genbuf[n++] = *name++;
.
678,679c
		while(*name!='\0' && (*name != '/' || n < 2)){
			if(n >= sizeof(up->genbuf)-1)
.
674,676c
		nomount = 1;
		up->genbuf[0] = '\0';
.
672a
	
.
669,671d
667c
		c = up->slash;
		incref(c);
.
646,665c
	/*
	 * 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]){
.
643,644c
	name = aname;
	if(name[0] == '\0')
		error("empty file name");
	validname(name, 1);
.
638,641c
	Elemlist e;
	Rune r;
	Mhead *m;
	char *name;
.
634,636c
	int n, t, nomount;
	Chan *c, *cnew;
.
632c
namec(char *aname, int amode, int omode, ulong perm)
.
629a
 *
 * 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.
.
627a
 * The name is known to be valid.
 * Copy the name so slashes can be overwritten.
 * An empty string will set nelem=0.
 */
static void
parsename(char *name, Elemlist *e)
{
	char *slash;

	kstrdup(&e->name, name);
	name = e->name;
	e->nelems = 0;
	e->elems = nil;
	for(;;){
		name = skipslash(name);
		if(*name=='\0')
			break;
		growparse(e);
		e->elems[e->nelems++] = name;
		slash = utfrune(name, '/');
		if(slash == nil)
			break;
		*slash++ = '\0';
		name = slash;
	}
}

/*
.
626a
static void
growparse(Elemlist *e)
{
	char **new;
	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;
	}
}

.
580,587c
	for(f = m->mount; f; f = f->next) {
		if(f->mflag&MCREATE) {
			nc = cclone(f->to);
			runlock(&m->lock);
.
577c
		runlock(&m->lock);
.
575c
	rlock(&m->lock);
.
570c
createdir(Chan *c, Mhead *m)
.
561,562c
	cclose(*cp);
	*cp = c;
if(chandebug) print("success\n");
.
554,559c
	c->name = cname;
.
552c
	putmhead(mh);

	c = cunique(c);
if(c->umh != nil){
	print("walk umh\n");
	putmhead(c->umh);
	c->umh = nil;
}

.
547,549c
		names += n;
		nnames -= n;
//print("nc %s nnames %d devchar %C qid %.8llux\n", cname->s, nnames, devtab[c->type]->dc, c->qid.path);
		free(wq);
.
544,545c
		for(i=0; i<n; i++)
			cname = addelem(cname, names[i]);
.
539,542c
		c = nc;
		putmhead(mh);
		mh = nmh;
.
526,537c
		if((wq = devtab[type]->walk(c, nil, names, ntry)) == nil){
if(chandebug) print("walk failed.");
			/* try a union mount, if any */
			if(mh == nil || nomount){
			Giveup:
if(chandebug) print("give up\n");
//delay(2000);
				cclose(c);
				cnameclose(cname);
				return -1;
			}

			rlock(&mh->lock);
			if(waserror()){
				runlock(&mh->lock);
				nexterror();
			}
			for(f = mh->mount; f; f = f->next)
{
if(chandebug) print("\ttry chan: qid %.8llux devchar %C dev %lud ->\n", c->qid.path, devtab[c->type]->dc, c->dev);
				if((wq = devtab[f->to->type]->walk(f->to, nil, names, ntry)) != nil)
					break;
}
			poperror();
			runlock(&mh->lock);

			if(wq == nil)
				goto Giveup;

			type = f->to->type;
			dev = f->to->dev;
		}

		nmh = nil;
		if(dotdot) {
			assert(wq->nqid == 1);
			assert(wq->clone != nil);
if(chandebug) print("undo.");
			nc = undomount(wq->clone, cname);
			n = 1;
		} else {
			nc = nil;
if(chandebug) print("find.");
			if(!nomount)
				for(i=0; i<wq->nqid && i<nnames-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);
					free(wq);
if(chandebug) print("fail\n");
					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;
			}
		}

.
524c
		type = c->type;
		dev = c->dev;
.
521,522c
if(chandebug){
print("\ttry chan: qid %.8llux devchar %C dev %lud ->\n", c->qid.path, devtab[c->type]->dc, c->dev);
for(i=0; i<ntry; i++)
	print(" %s", names[i]);
}
		if(!dotdot && !nomount)
			domount(&c, &mh);
.
512,519c
	/*
	 * 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.
	 */
	while(nnames > 0){
		ntry = nnames;
		if(ntry > MAXWELEM)
			ntry = MAXWELEM;
		dotdot = 0;
		for(i=0; i<nnames; i++){
			if(isdotdot(names[i])){
				if(i==0) {
					dotdot = 1;
					ntry = 1;
				} else
					ntry = i;
				break;
			}
		}
.
506,510c
if(chandebug){
print("walk");
for(i=0; i<nnames; i++)
	print(" %s", names[i]);
print("\n");
}
.
503,504c
	c = *cp;
	incref(c);
	cname = c->name;
	incref(cname);
	mh = nil;
.
501c
//BUG: waserror?
.
499c
	Mhead *mh, *nmh;
	Walkqid *wq;
.
497c
	int i, dotdot, n, ntry, type, dev;
	Chan *c, *nc;
	Cname *cname;
.
495c
walk(Chan **cp, char **names, int nnames, int nomount)
.
479,493c
/*
 * Either walks all the way or not at all.  No partial results.
 */
.
465,466c
					nc = t->head->from;
					incref(nc);
.
463c
					if(strcmp(t->head->from->name->s, name->s) != 0)
.
438c
undomount(Chan *c, Cname *name)
.
436a
int
domount(Chan **cp, Mhead **mp)
{
	return findmount(cp, mp, (*cp)->type, (*cp)->dev, (*cp)->qid);
}

.
434c
	return 0;
.
428c
			return 1;
.
415,426c
			if(mp != nil){
				incref(m);
				if(*mp != nil)
					putmhead(*mp);
				*mp = m;
			}
			if(*cp != nil)
				cclose(*cp);
			incref(m->mount->to);
			*cp = m->mount->to;
.
409,413c
if(m->from == nil){
	print("m %p m->from 0\n", m);
	runlock(&m->lock);
	continue;
}
		if(eqchantdqid(m->from, type, dev, qid, 1)) {
.
402,407c
	for(m = MOUNTH(pg, qid); m; m = m->hash){
.
397d
393,394c
int
findmount(Chan **cp, Mhead **mp, int type, int dev, Qid qid)
.
384,389c
	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);
.
382c
cclone(Chan *c)
.
332c
	l = &MOUNTH(pg, mnt->qid);
.
328a
if(mnt->umh)	/* should not happen */
	print("cmount newp extra umh\n");
if(mounted && mounted->umh)
	print("cmount old extra umh\n");

.
303c
		nm->mflag |= MCREATE;
.
289c
		um = mh->mount;
.
281c
	if(mh != nil && mh->mount != nil) {
.
259a
incref(&mheadcounter);
.
254c
	if(m == nil) {
.
247c
	l = &MOUNTH(pg, old->qid);
.
243a
	mh = nil;
	domount(newp, &mh);
	new = *newp;

	/*
	 * 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);

.
241c
	if((old->qid.type&QTDIR)==0 && order != MREPL)
.
238a
if((*newp)->umh)	/* should not happen */
	print("cmount newp extra umh\n");
if(old->umh)
	print("cmount old extra umh\n");

.
236c
	if(QTDIR & (old->qid.type^(*newp)->qid.type))
.
234a
	Chan *new;
.
233c
	Mhead *m, **l, *mh;
.
230a
	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;
}

int
cmount(Chan **newp, Chan *old, int flag, char *spec)
{
.
229c
eqchantdqid(Chan *a, int type, int dev, Qid qid, int pathonly)
.
207a
/*
 * Make sure we have the only copy of c.  (Copy on write.)
 */
Chan*
cunique(Chan *c)
{
	Chan *nc;

	if(c->ref != 1) {
		nc = cclone(c);
		cclose(c);
		c = nc;
	}

	return c;
}

.
179a
	if(c->umc != nil){
		cclose(c->umc);
		c->umc = nil;
	}
.
175,178c
	if(c->umh != nil){
		putmhead(c->umh);
		c->umh = nil;
.
171,173c
	if(c->version){
		free(c->version);
		c->version = 0;
.
162a
	if(isdotdot(s))
		cleancname(n);
.
142a
	if(s[0]=='.' && s[1]=='\0')
		return n;

.
127c
	if(n == nil)
.
101a
	c->version = 0;
.
100c
	memset(&c->mqid, 0, sizeof(c->mqid));
.
94,95c
	c->iounit = 0;
	c->umh = 0;
.
84a
if(chandebug) print("newchan %d\n", c->fid);
.
78c
	if(c == nil) {
.
49a
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;
	static Lock l;

	n = strlen(s)+1;
//	if(n == 1){
//		ulong pc;
//		int i;
//		static ulong pcs[128];
//		pc = getcallerpc(&p);
//		for(i=0; i<nelem(pcs) && pcs[i]; i++)
//			if(pc == pcs[i])
//				break;
//		if(up!=nil && i<nelem(pcs) && pcs[i]==0){
//			pcs[i] = pc;
//			print("kstrdup(null string) called from 0x%lux\n", pc);
//		}
//	}
	/* 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
.
48a
/*
 * 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;
 */
.
24a
isdotdot(char *p)
{
	return p[0]=='.' && p[1]=='.' && p[2]=='\0';
}

int
.
20a
typedef struct Elemlist Elemlist;

struct Elemlist
{
	char	*name;	/* copy of name, so '/' can be overwritten */
	int	nelems;
	char	**elems;
};

.
7a
int chandebug=0;		/* toggled by sysr1 */

/* transition BUG */
int client9p = 2;
int kernel9p = 2;


int domount(Chan**, Mhead**);
Ref mheadcounter;

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)\n", t, t->to->name->s, t->to->umh);
		}
	}
	poperror();
	runlock(&pg->ns);
}

.
## diffname port/chan.c 2001/0530
## diff -e /n/emeliedump/2001/0527/sys/src/9/port/chan.c /n/emeliedump/2001/0530/sys/src/9/port/chan.c
806a
if(chandebug) print("undidmount nc %s...", nc->name->s);
.
805c
if(chandebug) print("undo wq->clone->name %s cname %s...", wq->clone->name->s, cname->s);
.
## diffname port/chan.c 2001/0601
## diff -e /n/emeliedump/2001/0530/sys/src/9/port/chan.c /n/emeliedump/2001/0601/sys/src/9/port/chan.c
863c
if(chandebug)
print("[%lud]\twalk succeeds; name %s chan (path %.8llux dev %C %lud)\n", up->pid, c2name(c), c->qid.path, devtab[c->type]->dc, c->dev);
.
845d
840,842d
832a
			for(i=0; i<n; i++)
				cname = addelem(cname, names[i]);
.
826a
if(chandebug){int j;
qlock(&chanprint);
print("[%lud]\tfound mount point: ", up->pid);
for(j=0; j<=i; j++)
	print("%s%s", j?"/":"", names[j]);
print(" becomes ");
print("%s\n", c2name(nc));
qunlock(&chanprint);
}
.
821d
816a
if(chandebug)
print("[%lud]\tno mount points along path\n", up->pid);
.
811d
807c
if(chandebug)
print("[%lud]\tundo returned %s\n", up->pid, c2name(nc));
.
805c

			cname = addelem(cname, "..");
if(chandebug)
print("[%lud]\tundo wq->clone %s cname %s\n", up->pid, c2name(wq->clone), cname?cname->s:"<nil name>");
.
787c
if(chandebug)
 print("[%lud]\twalk from %s (path %.8llux dev %C %lud)\n", 
  up->pid, c2name(c), c->qid.path, devtab[c->type]->dc, c->dev);
.
773,774c
if(chandebug) print("[%lud]\tgive up\n", up->pid);
.
769c
if(chandebug) print("[%lud]\twalk failed.\n", up->pid);
.
760c
	print("%s%s", i?"/":"", names[i]);
print("\n");
qunlock(&chanprint);
.
758c
qlock(&chanprint);
print("[%lud]\twalk from %s (path %.8llux dev %C %lud) to ", 
	up->pid, c2name(c), c->qid.path, devtab[c->type]->dc, c->dev);
.
728a
qunlock(&chanprint);
.
727c
	print("%s%s", i?"/":"", names[i]);
.
725c
qlock(&chanprint);
print("[%lud] walk %s to ", up->pid, c2name(c));
.
692a
if(chandebug)
print("[%lud]\tundomount found %s\n", up->pid, c2name(c));
.
678a
			if(strcmp(f->from->name->s, name->s) != 0)
				continue;
if(chandebug)
print("[%lud]\tundomount found head %s; need chan (path %.8llux dev %C %lud)\n",
	up->pid, name->s, c->qid.path, devtab[c->type]->dc, c->dev);
.
228d
54a

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;
}

.
48c
				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);
.
14d
8a
QLock chanprint;		/* probably asking for trouble (deadlocks) -rsc */
.
## diffname port/chan.c 2001/0803
## diff -e /n/emeliedump/2001/0601/sys/src/9/port/chan.c /n/emeliedump/2001/0803/sys/src/9/port/chan.c
559c
	print("cunmount old extra umh\n");
.
557c
	print("cunmount newp extra umh\n");
.
## diffname port/chan.c 2001/0819
## diff -e /n/emeliedump/2001/0803/sys/src/9/port/chan.c /n/emeliedump/2001/0819/sys/src/9/port/chan.c
900,901d
894a
	if(c->umh != nil){	//BUG
		print("walk umh\n");
		putmhead(c->umh);
		c->umh = nil;
	}

.
889,893d
875d
857,865d
846,847d
836,837d
833,834d
816d
810,813d
798d
794d
778,786d
743,751d
735,736d
710,711d
693,695d
358a

.
344a
	if(c->mux != nil){
		muxclose(c->mux);
		c->mux = nil;
	}
	if(c->mchan != nil){
		cclose(c->mchan);
		c->mchan = nil;
	}
.
333,336d
258d
255a
	c->mux = 0;
.
177,189d
## diffname port/chan.c 2001/0822
## diff -e /n/emeliedump/2001/0819/sys/src/9/port/chan.c /n/emeliedump/2001/0822/sys/src/9/port/chan.c
1244a

.
1226c
				error(createerr);	/* report true error */
.
1224a
			/* save error */
			kstrcpy(createerr, up->error, sizeof createerr);
.
1108,1111c
			if(omode & OCEXEC)
				c->flag |= CCEXEC;
			if(omode & ORCLOSE)
				c->flag |= CRCLOSE;
			break;
		}
.
1106c
			c = devtab[c->type]->open(c, omode&~OCEXEC);
.
1103,1104c
			if(omode == OEXEC)
				c->flag &= ~CCACHE;
.
1100,1101c
			/* save registers else error() in open has wrong value of c saved */
			saveregisters();
.
1098c
			if(c->qid.type&QTDIR)
				c->umh = m;
			else
				putmhead(m);
.
1093a
		case Aopen:
		case Acreate:
.
1092d
1089c
		switch(amode){
		case Aremove:
.
971a
	char createerr[ERRMAX];
.
774c
			for(f = mh->mount->next; f; f = f->next)
.
551c
	print("cunmount old extra umh %p has %p\n", mounted, mounted->umh);
.
549c
	print("cunmount newp extra umh %p has %p\n", mnt, mnt->umh);
.
239a
	c->dri = 0;
.
## diffname port/chan.c 2001/0823
## diff -e /n/emeliedump/2001/0822/sys/src/9/port/chan.c /n/emeliedump/2001/0823/sys/src/9/port/chan.c
1102c

			/* only save the mount head if it's a multiple element union */
			if(m && m->mount && m->mount->next)
.
## diffname port/chan.c 2001/0912
## diff -e /n/emeliedump/2001/0823/sys/src/9/port/chan.c /n/emeliedump/2001/0912/sys/src/9/port/chan.c
549,552c
	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.
	 */
.
## diffname port/chan.c 2001/0919
## diff -e /n/emeliedump/2001/0912/sys/src/9/port/chan.c /n/emeliedump/2001/0919/sys/src/9/port/chan.c
1078a
		break;

	case Abind:
		m = nil;
		if(!nomount)
			domount(&c, &m);
		c->umh = m;
.
441a
	mh = new->umh;
.
439,440d
429,430d
## diffname port/chan.c 2001/0922
## diff -e /n/emeliedump/2001/0919/sys/src/9/port/chan.c /n/emeliedump/2001/0922/sys/src/9/port/chan.c
1239a
			c->name = addelem(c->name, e.elems[e.nelems-1]);
.
## diffname port/chan.c 2001/0924
## diff -e /n/emeliedump/2001/0922/sys/src/9/port/chan.c /n/emeliedump/2001/0924/sys/src/9/port/chan.c
1251a
			}
			up->errstr = createerr;
.
1249,1250c
			createerr = up->errstr;
			up->errstr = tmperrbuf;
			/* note: we depend that walk does not error */
			if(walk(&c, e.elems+e.nelems-1, 1, nomount) < 0){
				up->errstr = createerr;
.
1046c
				snprint(up->errstr, ERRMAX, "file \"...%s\" does not exist", name);
.
1044c
				snprint(up->errstr, ERRMAX, "\"%s\" does not exist", aname);
.
1042c
		if(strcmp(up->errstr, Enonexist) == 0){
.
977c
	char *createerr, tmperrbuf[ERRMAX];
.
778a
			/*
			 * mh->mount == c, so start at mh->mount->next
			 */
.
## diffname port/chan.c 2001/0926
## diff -e /n/emeliedump/2001/0924/sys/src/9/port/chan.c /n/emeliedump/2001/0926/sys/src/9/port/chan.c
356c
//		print("cclose error: type %C; error %s\n", devtab[c->type]->dc, up!=nil? up->errstr : "no user");
.
## diffname port/chan.c 2001/1118
## diff -e /n/emeliedump/2001/0926/sys/src/9/port/chan.c /n/emeliedump/2001/1118/sys/src/9/port/chan.c
1167d
1164,1165c
			if(omode&OEXCL)
.
## diffname port/chan.c 2001/1130
## diff -e /n/emeliedump/2001/1118/sys/src/9/port/chan.c /n/emeliedump/2001/1130/sys/src/9/port/chan.c
356,357c
		print("cclose error: type %C; error %s\n", devtab[c->type]->dc, up!=nil? up->errstr : "no user");
		/* don't chanfree: better leak than leave a dangling pointer */
.
## diffname port/chan.c 2001/1204
## diff -e /n/emeliedump/2001/1130/sys/src/9/port/chan.c /n/emeliedump/2001/1204/sys/src/9/port/chan.c
360,362d
355,358c
	if(!waserror()){
		devtab[c->type]->close(c);
		poperror();
.
## diffname port/chan.c 2001/1213
## diff -e /n/emeliedump/2001/1204/sys/src/9/port/chan.c /n/emeliedump/2001/1213/sys/src/9/port/chan.c
802c
				for(i=0; i<wq->nqid && i<ntry-1; i++)
.
## diffname port/chan.c 2002/0104
## diff -e /n/emeliedump/2001/1213/sys/src/9/port/chan.c /n/emeliedump/2002/0104/sys/src/9/port/chan.c
1271a
	free(e.off);
.
1249c
			if(walk(&c, e.elems+e.nelems-1, 1, nomount, nil) < 0){
.
1159c
		if(walk(&c, e.elems+e.nelems-1, 1, nomount, nil) == 0){
.
1068,1069c
	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();
		}
		len = prefix+e.off[npath];
		strcpy(tmperrbuf, up->errstr);
		if(len < ERRMAX/3 || (name=memrchr(aname, '/', len))==nil || name==aname)
			snprint(up->errstr, ERRMAX, "\"%.*s\" %s", len, aname, tmperrbuf);
		else
			snprint(up->errstr, ERRMAX, "\"...%.*s\" %s", (int)(len-(name-aname)), name, tmperrbuf);
		nexterror();
	}
.
1049a
		free(e.off);
.
1041,1046d
1039a
	e.off = nil;
	e.nelems = 0;
.
1036a
	prefix = name - aname;
.
970c
	int n, prefix, len, t, nomount, npath;
.
950a
void*
memrchr(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;
}

.
945a
		}
		e->off[e->nelems] = slash - e->name;
.
944c
		if(slash == nil){
			e->off[e->nelems] = name+strlen(name) - e->name;
.
941a
		
.
936a
	e->off = smalloc(sizeof(int));
	e->off[0] = 0;
.
919a
		inew = smalloc((e->nelems+Delta+1) * sizeof(int));
		memmove(inew, e->off, e->nelems*sizeof(int));
		free(e->off);
		e->off = inew;
.
912a
	int *inew;
.
848a
	if(nerror)
		*nerror = 0;
.
828,830d
822c
				cname = addelem(cname, names[nhave+i]);
.
808a
					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);
					}
.
769,788d
766a
				if(nerror)
					*nerror = nhave+1;
.
763,764c
			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){
.
761c
		if((wq = devtab[type]->walk(c, nil, names+nhave, ntry)) == nil){
.
744,745c
		for(i=0; i<ntry; i++){
			if(isdotdot(names[nhave+i])){
.
739,740c
	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);
			return -1;
		}
		ntry = nnames - nhave;
.
716c
	int dev, dotdot, i, n, nhave, ntry, type;
.
714c
walk(Chan **cp, char **names, int nnames, int nomount, int *nerror)
.
712a
static char Edoesnotexist[] = "does not exist";
.
711c
 * 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.
.
87a
	int	*off;
.
## diffname port/chan.c 2002/0109
## diff -e /n/emeliedump/2002/0104/sys/src/9/port/chan.c /n/emeliedump/2002/0109/sys/src/9/port/chan.c
210a
void
chandevshutdown(void)
{
	int i;
	
	/* shutdown in reverse order */
	for(i=0; devtab[i] != nil; i++)
		;
	for(i--; i >= 0; i--)
		devtab[i]->shutdown();
}

.
## diffname port/chan.c 2002/0115
## diff -e /n/emeliedump/2002/0109/sys/src/9/port/chan.c /n/emeliedump/2002/0115/sys/src/9/port/chan.c
11,14d
## diffname port/chan.c 2002/0411
## diff -e /n/emeliedump/2002/0115/sys/src/9/port/chan.c /n/emeliedump/2002/0411/sys/src/9/port/chan.c
1432d
1394,1395c
				if(!slashok || c!='/'){
					snprint(up->genbuf, sizeof(up->genbuf), "%s: %q", Ebadchar, aname);
					error(up->genbuf);
			}
.
1373a
	name = aname;
.
1369c
	char *p, *ename, *name;
.
1367c
validname(char *aname, int slashok)
.
481d
12d
## diffname port/chan.c 2002/0416
## diff -e /n/emeliedump/2002/0411/sys/src/9/port/chan.c /n/emeliedump/2002/0416/sys/src/9/port/chan.c
1119c
			snprint(up->genbuf, sizeof up->genbuf, "...%.*s", (int)(len-(name-aname)), name);
		snprint(up->errstr, ERRMAX, "%#q %s", up->genbuf, tmperrbuf);
.
1117c
			snprint(up->genbuf, sizeof up->genbuf, "%.*s", len, aname);
.
## diffname port/chan.c 2002/0731
## diff -e /n/emeliedump/2002/0416/sys/src/9/port/chan.c /n/emeliedump/2002/0731/sys/src/9/port/chan.c
1163a
	c->umh = nil;
.
1162c
	print("cunique umh Open\n");
.
1133a
		if(c->umh != nil)
			putmhead(c->umh);
.
609a
	wunlock(&pg->ns);
.
604a
			wunlock(&pg->ns);
.
600a
				wunlock(&pg->ns);
.
587d
479,483c
		m = newmhead(old);
.
433,434c
if(old->umh)print("cmount old extra umh\n");
.
420a
Mhead*
newmhead(Chan *from)
{
	Mhead *mh;
	int n;

	mh = smalloc(sizeof(Mhead));
	mh->ref = 1;
	mh->from = from;
	incref(from);

	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;
}

.
## diffname port/chan.c 2002/0801
## diff -e /n/emeliedump/2002/0731/sys/src/9/port/chan.c /n/emeliedump/2002/0801/sys/src/9/port/chan.c
847a
					if(mh != nil)
						putmhead(mh);
.
815a
				if(mh != nil)
					putmhead(mh);
.
771a
			if(mh != nil)
{print("walk 1\n");
				putmhead(mh);
}
.
## diffname port/chan.c 2002/0830
## diff -e /n/emeliedump/2002/0801/sys/src/9/port/chan.c /n/emeliedump/2002/0830/sys/src/9/port/chan.c
115c
		panic("decref, pc=0x%lux", getcallerpc(&r));
.
## diffname port/chan.c 2002/0911
## diff -e /n/emeliedump/2002/0830/sys/src/9/port/chan.c /n/emeliedump/2002/0911/sys/src/9/port/chan.c
437c
*/
.
431a
/*
.
425d
## diffname port/chan.c 2003/0303
## diff -e /n/emeliedump/2002/0911/sys/src/9/port/chan.c /n/emeliedump/2003/0303/sys/src/9/port/chan.c
1367,1370d
1364,1365c
	while(name[0]=='/' || (name[0]=='.' && (name[1]==0 || name[1]=='/')))
.
1359c
 * name is valid. skip leading / and ./ as much as possible
.
1148a
	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");
	}

.
1140a
	NameError:
		len = prefix+e.off[npath];
.
1139d
1130c
			error(Eexist);
.
1128a
		/* 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. */
.
1126c
	 * On create, ....
.
1102d
1062d
998a
			e->mustbedir = 0;
.
994d
992a
		}
.
991c
		if(*name=='\0'){
			e->mustbedir = 1;
.
988c
	e->off[0] = skipslash(name) - name;
.
976a
 * 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.
.
83a
	int	mustbedir;
.
## diffname port/chan.c 2003/0509
## diff -e /n/emeliedump/2003/0303/sys/src/9/port/chan.c /n/emeliedump/2003/0509/sys/src/9/port/chan.c
1218d
1206a
		case Aaccess:
.
1205a
		/* record whether c is on a mount point */
		c->ismtpt = m!=nil;

.
1188a
	case Aaccess:
.
1175,1179d
1165,1166c
		nameerror(aname, "not a directory");
.
1152,1160c
		nameerror(aname, up->errstr);
.
1137,1138c
			nameerror(aname, "create without DMDIR");
.
1110d
1045c
	int n, t, nomount, npath;
.
1037,1040c
 * Under certain circumstances, opening Aaccess will cause
 * an unnecessary clone in order to get a cunique Chan so it
 * can attach the correct name.  Sysstat and sys_stat need the
 * correct name so they can rewrite the stat info.
.
1035c
 * Opening Atodir or Amount does not guarantee this.
.
1030c
 * Opening with amode Aopen, Acreate, Aremove, or Aaccess guarantees
.
1025a
void
nameerror(char *name, char *error)
{
	int len;
	char tmperr[ERRMAX], *p;

	strcpy(tmperr, error);	/* error might be in genbuf or tmperr */
	len = strlen(name);
	if(len < ERRMAX/3 || (p=strrchr(name, '/'))==nil || p==name)
		snprint(up->genbuf, sizeof up->genbuf, "%s", name);
	else
		snprint(up->genbuf, sizeof up->genbuf, "...%s", p);
	snprint(up->errstr, ERRMAX, "%#q %s", up->genbuf, tmperr);
	nexterror();
}

.
835c
		}else{
.
828c
		if(dotdot){
.
804c
				 * mh->mount->to == c, so start at mh->mount->next
.
776d
774d
658,663c
		if(m->from == nil){
			print("m %p m->from 0\n", m);
			runlock(&m->lock);
			continue;
		}
		if(eqchantdqid(m->from, type, dev, qid, 1)){
.
329a
	if(c->dirrock != nil){
		free(c->dirrock);
		c->dirrock = 0;
		c->nrock = 0;
		c->mrock = 0;
	}
.
255a
	c->ismtpt = 0;
.
245a
	c->devoffset = 0;
.
52c
channame(Chan *c)		/* DEBUGGING */
.