Subversion Repositories planix.SVN

#include	<u.h>

#include	<libc.h>

#include	<fcall.h>

#include	"compat.h"

#include	"error.h"

extern ulong	kerndate;

void

mkqid(Qid *q, vlong path, ulong vers, int type)

{

	q->type = type;

	q->vers = vers;

	q->path = path;

}

int

devno(int c, int user)

{

	int i;

	for(i = 0; devtab[i] != nil; i++){

		if(devtab[i]->dc == c)

			return i;

	}

	if(user == 0)

		panic("devno %C 0x%ux", c, c);

	return -1;

}

void

devdir(Chan *c, Qid qid, char *n, vlong length, char *user, long perm, Dir *db)

{

	db->name = n;

	db->qid = qid;

	db->type = devtab[c->type]->dc;

	db->dev = c->dev;

	db->mode = (qid.type << 24) | perm;

	db->atime = seconds();

	db->mtime = kerndate;

	db->length = length;

	db->uid = user;

	db->gid = eve;

	db->muid = user;

}

/*

 * the zeroth element of the table MUST be the directory itself for ..

*/

int

devgen(Chan *c, Dirtab *tab, int ntab, int i, Dir *dp)

{

	if(tab == 0)

		return -1;

	if(i != DEVDOTDOT){

		i++; /* skip first element for . itself */

		if(i >= ntab)

			return -1;

		tab += i;

	}

	devdir(c, tab->qid, tab->name, tab->length, eve, tab->perm, dp);

	return 1;

}

void

devreset(void)

{

}

void

devinit(void)

{

}

Chan*

devattach(int tc, char *spec)

{

	Chan *c;

	char *buf;

	c = newchan();

	mkqid(&c->qid, 0, 0, QTDIR);

	c->type = devno(tc, 0);

	if(spec == nil)

		spec = "";

	buf = smalloc(4+strlen(spec)+1);

	sprint(buf, "#%C%s", tc, spec);

	c->name = newcname(buf);

	free(buf);

	return c;

}

Chan*

devclone(Chan *c)

{

	Chan *nc;

	if(c->flag & COPEN)

		panic("clone of open file type %C\n", devtab[c->type]->dc);

	nc = newchan();

	nc->type = c->type;

	nc->dev = c->dev;

	nc->mode = c->mode;

	nc->qid = c->qid;

	nc->offset = c->offset;

	nc->aux = c->aux;

	return nc;

}

Walkqid*

devwalk(Chan *c, Chan *nc, char **name, int nname, Dirtab *tab, int ntab, Devgen *gen)

{

	int i, j, alloc;

	Walkqid *wq;

	char *n;

	Dir dir;

	isdir(c);

	alloc = 0;

	wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid));

	if(waserror()){

		if(alloc && wq->clone!=nil)

			cclose(wq->clone);

		free(wq);

		return nil;

	}

	if(nc == nil){

		nc = devclone(c);

		nc->type = 0;	/* device doesn't know about this channel yet */

		alloc = 1;

	}

	wq->clone = nc;

	for(j=0; j<nname; j++){

		isdir(nc);

		n = name[j];

		if(strcmp(n, ".") == 0){

    Accept:

			wq->qid[wq->nqid++] = nc->qid;

			continue;

		}

		if(strcmp(n, "..") == 0){

			(*gen)(nc, tab, ntab, DEVDOTDOT, &dir);

			nc->qid = dir.qid;

			goto Accept;

		}

		for(i=0;; i++){

			switch((*gen)(nc, tab, ntab, i, &dir)){

			case -1:

				if(j == 0)

					error(Enonexist);

				strncpy(up->error, Enonexist, ERRMAX);

				goto Done;

			case 0:

				continue;

			case 1:

				if(strcmp(n, dir.name) == 0){

					nc->qid = dir.qid;

					goto Accept;

				}

				continue;

			}

		}

	}

	/*

	 * We processed at least one name, so will return some data.

	 * If we didn't process all nname entries succesfully, we drop

	 * the cloned channel and return just the Qids of the walks.

	 */

Done:

	poperror();

	if(wq->nqid < nname){

		if(alloc)

			cclose(wq->clone);

		wq->clone = nil;

	}else if(wq->clone){

		/* attach cloned channel to same device */

		wq->clone->type = c->type;

	}

	return wq;

}

int

devstat(Chan *c, uchar *db, int n, Dirtab *tab, int ntab, Devgen *gen)

{

	int i;

	Dir dir;

	char *p, *elem;

	for(i=0;; i++)

		switch((*gen)(c, tab, ntab, i, &dir)){

		case -1:

			if(c->qid.type & QTDIR){

				if(c->name == nil)

					elem = "???";

				else if(strcmp(c->name->s, "/") == 0)

					elem = "/";

				else

					for(elem=p=c->name->s; *p; p++)

						if(*p == '/')

							elem = p+1;

				devdir(c, c->qid, elem, 0, eve, DMDIR|0555, &dir);

				return convD2M(&dir, db, n);

			}

			error(Enonexist);

		case 0:

			break;

		case 1:

			if(c->qid.path == dir.qid.path){

				return convD2M(&dir, db, n);

			}

			break;

		}

}

long

devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)

{

	long k, m, dsz;

	struct{

		Dir;

		char slop[100];

	}dir;

	k = c->offset;

	for(m=0; m<n; k++){

		switch((*gen)(c, tab, ntab, k, &dir)){

		case -1:

			return m;

		case 0:

			c->offset++;	/* BUG??? (was DIRLEN: skip entry) */

			break;

		case 1:

			dsz = convD2M(&dir, (uchar*)d, n-m);

			if(dsz <= BIT16SZ){	/* <= not < because this isn't stat; read is stuck */

				if(m == 0)

					return -1;

				return m;

			}

			m += dsz;

			d += dsz;

			break;

		}

	}

	return m;

}

/*

 * error(Eperm) if open permission not granted for up->user.

 */

void

devpermcheck(char *fileuid, ulong perm, int omode)

{

	ulong t;

	static int access[] = { 0400, 0200, 0600, 0100 };

	if(strcmp(up->user, fileuid) == 0)

		perm <<= 0;

	else

	if(strcmp(up->user, eve) == 0)

		perm <<= 3;

	else

		perm <<= 6;

	t = access[omode&3];

	if((t&perm) != t)

		error(Eperm);

}

Chan*

devopen(Chan *c, int omode, Dirtab *tab, int ntab, Devgen *gen)

{

	int i;

	Dir dir;

	for(i=0;; i++){

		switch((*gen)(c, tab, ntab, i, &dir)){

		case -1:

			goto Return;

		case 0:

			break;

		case 1:

			if(c->qid.path == dir.qid.path){

				devpermcheck(dir.uid, dir.mode, omode);

				goto Return;

			}

			break;

		}

	}

Return:

	c->offset = 0;

	if((c->qid.type&QTDIR) && omode!=OREAD)

		error(Eperm);

	c->mode = openmode(omode);

	c->flag |= COPEN;

	return c;

}

void

devcreate(Chan*, char*, int, ulong)

{

	error(Eperm);

}

Block*

devbread(Chan *, long, ulong)

{

	panic("no block read");

	return nil;

}

long

devbwrite(Chan *, Block *, ulong)

{

	panic("no block write");

	return 0;

}

void

devremove(Chan*)

{

	error(Eperm);

}

int

devwstat(Chan*, uchar*, int)

{

	error(Eperm);

	return 0;

}