#include	"lib9.h"#include	"sys.h"#include	"error.h" static ulong	kerndate; intdevno(int c, int user){	Rune *s;	int i; 	s = devchar;	i = 0;	while(*s){		if(c == *s)			return i;		i++;		s++;	} 	if(user)		return -1;	panic("devno %C 0x%ux", c, c);	return 0;} voiddevinit(void){} voiddevreset(void){} voiddevcreate(Chan *c, char *name, int mode, ulong perm){	USED(c);	USED(name);	USED(mode);	USED(perm); 	error(Eperm);} voiddevremove(Chan *c){	USED(c); 	error(Eperm);} voiddevwstat(Chan *c, char *s){	USED(c);	USED(s); 	error(Eperm);}  voiddevdir(Chan *c, Qid qid, char *n, long length, char *user, long perm, Dir *db){	strcpy(db->name, n);	db->qid = qid;	db->type = devchar[c->type];	db->dev = c->dev;	db->mode = perm;	if(qid.path & CHDIR)		db->mode |= CHDIR;	if(c->flag&CMSG)		db->mode |= CHMOUNT;	db->atime = time(0);	db->mtime = kerndate;	db->length = length;	memmove(db->uid, user, NAMELEN);	memmove(db->gid, eve, NAMELEN);} intdevgen(Chan *c, Dirtab *tab, int ntab, int i, Dir *dp){	Qid qid; 	if(tab==0 || i>=ntab)		return -1;	tab += i;	qid = tab->qid;	/* avoid unaligned access in digital unix */	devdir(c, qid, tab->name, tab->length, eve, tab->perm, dp);	return 1;} Chan*devattach(int tc, char *spec){	Chan *c;	char buf[NAMELEN+4]; 	c = newchan();	c->qid.path = CHDIR;	c->qid.vers = 0; 	c->type = devno(tc, 0);	if(tc != 'M') {		sprint(buf, "#%C%s", tc, spec);		c->path = ptenter(&syspt, 0, buf);	}	return c;} Chan *devclone(Chan *c, Chan *nc){	if(c->flag & COPEN)		panic("clone of open file type %C\n", devchar[c->type]); 	if(nc == 0)		nc = newchan(); 	nc->type = c->type;	nc->dev = c->dev;	nc->mode = c->mode;	nc->qid = c->qid;	nc->offset = c->offset;	nc->flag = c->flag;	nc->mnt = c->mnt;	nc->mountid = c->mountid;	nc->u = c->u;	nc->mchan = c->mchan;	nc->mqid = c->mqid;	nc->path = c->path;	refinc(&nc->path->r);	return nc;} intdevwalk(Chan *c, char *name, Dirtab *tab, int ntab, Devgen *gen){	long i;	Dir dir;	Path *op; 	isdir(c);	if(name[0]=='.' && name[1]==0)		return 1;	for(i=0;; i++) {		switch((*gen)(c, tab, ntab, i, &dir)){		case -1:			strncpy(threaderr(), Enonexist, NAMELEN);			return 0;		case 0:			continue;		case 1:			if(strcmp(name, dir.name) == 0) {				c->qid = dir.qid;				op = c->path;				c->path = ptenter(&syspt, op, name);				refdec(&op->r);				return 1;			}			continue;		}	}	return 0;	/* not reached */} voiddevstat(Chan *c, char *db, Dirtab *tab, int ntab, Devgen *gen){	int i;	Dir dir;	Qid cqid, dirqid; 	for(i=0;; i++)		switch((*gen)(c, tab, ntab, i, &dir)){		case -1:			if(c->qid.path & CHDIR){				devdir(c, c->qid, c->path->elem, i*DIRLEN, eve, CHDIR|0555, &dir);				convD2M(&dir, db);				return;			}			print("%s: devstat %C %lux\n",				up->user, devchar[c->type], c->qid.path);			error(Enonexist);		case 0:			break;		case 1:			cqid = c->qid;			dirqid = dir.qid;			if(eqqid(cqid, dirqid)) {				if(c->flag&CMSG)					dir.mode |= CHMOUNT;				convD2M(&dir, db);				return;			}			break;		}} longdevdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen){	long k, m;	Dir dir; 	k = c->offset/DIRLEN;	for(m=0; m<n; k++) {		switch((*gen)(c, tab, ntab, k, &dir)){		case -1:			return m; 		case 0:			c->offset += DIRLEN;			break; 		case 1:			convD2M(&dir, d);			m += DIRLEN;			d += DIRLEN;			break;		}	} 	return m;} Chan *devopen(Chan *c, int omode, Dirtab *tab, int ntab, Devgen *gen){	int i;	Dir dir;	Qid cqid, dirqid;	ulong t, mode;	static int access[] = { 0400, 0200, 0600, 0100 }; 	for(i=0;; i++) {		switch((*gen)(c, tab, ntab, i, &dir)){		case -1:			goto Return;		case 0:			break;		case 1:			cqid = c->qid;			dirqid = dir.qid;			if(eqqid(cqid, dirqid)) {				if(strcmp(up->user, dir.uid) == 0)					mode = dir.mode;				else				if(strcmp(up->user, eve) == 0)					mode = dir.mode<<3;				else					mode = dir.mode<<6; 				t = access[omode&3];				if((t & mode) == t)					goto Return;				error(Eperm);			}			break;		}	}Return:	c->offset = 0;	if((c->qid.path&CHDIR) && omode!=OREAD)		error(Eperm);	c->mode = openmode(omode);	c->flag |= COPEN;	return c;} Block*devbread(Chan *c, long n, ulong offset){	Block *bp; 	bp = allocb(n);	if(bp == 0)		error(Enomem);	if(waserror()) {		freeb(bp);		nexterror();	}	bp->wp += devtab[c->type].read(c, bp->wp, n, offset);	poperror();	return bp;} longdevbwrite(Chan *c, Block *bp, ulong offset){	long n; 	n = devtab[c->type].write(c, bp->rp, BLEN(bp), offset);	freeb(bp); 	return n;	} intreadstr(ulong off, char *buf, ulong n, char *str){	int size; 	size = strlen(str);	if((int)off >= size)		return 0;	if((int)(off+n) > size)		n = size-off;	memmove(buf, str+off, n);	return n;} intopenmode(ulong o){	if(o >= (OTRUNC|OCEXEC|ORCLOSE|OEXEC))		error(Ebadarg);	o &= ~(OTRUNC|OCEXEC|ORCLOSE);	if(o > OEXEC)		error(Ebadarg);	if(o == OEXEC)		return OREAD;	return o;}