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- #include "u.h"
- #include "../port/lib.h"
- #include "mem.h"
- #include "dat.h"
- #include "fns.h"
- #include "../port/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 %#ux", c, c);
- return -1;
- }
- void
- devdir(Chan *c, Qid qid, char *n, vlong length, char *user, long perm, Dir *db)
- {
- db->name = n;
- if(c->flag&CMSG)
- qid.type |= QTMOUNT;
- db->qid = qid;
- db->type = devtab[c->type]->dc;
- db->dev = c->dev;
- db->mode = perm;
- db->mode |= qid.type << 24;
- db->atime = seconds();
- db->mtime = kerndate;
- db->length = length;
- db->uid = user;
- db->gid = eve;
- db->muid = user;
- }
- /*
- * (here, Devgen is the prototype; devgen is the function in dev.c.)
- *
- * a Devgen is expected to return the directory entry for ".."
- * if you pass it s==DEVDOTDOT (-1). otherwise...
- *
- * there are two contradictory rules.
- *
- * (i) if c is a directory, a Devgen is expected to list its children
- * as you iterate s.
- *
- * (ii) whether or not c is a directory, a Devgen is expected to list
- * its siblings as you iterate s.
- *
- * devgen always returns the list of children in the root
- * directory. thus it follows (i) when c is the root and (ii) otherwise.
- * many other Devgens follow (i) when c is a directory and (ii) otherwise.
- *
- * devwalk assumes (i). it knows that devgen breaks (i)
- * for children that are themselves directories, and explicitly catches them.
- *
- * devstat assumes (ii). if the Devgen in question follows (i)
- * for this particular c, devstat will not find the necessary info.
- * with our particular Devgen functions, this happens only for
- * directories, so devstat makes something up, assuming
- * c->name, c->qid, eve, DMDIR|0555.
- *
- * devdirread assumes (i). the callers have to make sure
- * that the Devgen satisfies (i) for the chan being read.
- */
- /*
- * the zeroth element of the table MUST be the directory itself for ..
- */
- int
- devgen(Chan *c, char *name, Dirtab *tab, int ntab, int i, Dir *dp)
- {
- if(tab == 0)
- return -1;
- if(i == DEVDOTDOT){
- /* nothing */
- }else if(name){
- for(i=1; i<ntab; i++)
- if(strcmp(tab[i].name, name) == 0)
- break;
- if(i==ntab)
- return -1;
- tab += i;
- }else{
- /* skip over the first element, that for . itself */
- i++;
- 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)
- {
- }
- void
- devshutdown(void)
- {
- }
- Chan*
- devattach(int tc, char *spec)
- {
- int n;
- Chan *c;
- char *buf;
- c = newchan();
- mkqid(&c->qid, 0, 0, QTDIR);
- c->type = devno(tc, 0);
- if(spec == nil)
- spec = "";
- n = 1+UTFmax+strlen(spec)+1;
- buf = smalloc(n);
- snprint(buf, n, "#%C%s", tc, spec);
- c->path = newpath(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->umh = nil;
- nc->aux = c->aux;
- nc->mqid = c->mqid;
- nc->mcp = c->mcp;
- 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;
- if(nname > 0)
- 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++){
- if(!(nc->qid.type&QTDIR)){
- if(j==0)
- error(Enotdir);
- goto Done;
- }
- n = name[j];
- if(strcmp(n, ".") == 0){
- Accept:
- wq->qid[wq->nqid++] = nc->qid;
- continue;
- }
- if(strcmp(n, "..") == 0){
- if((*gen)(nc, nil, tab, ntab, DEVDOTDOT, &dir) != 1){
- print("devgen walk .. in dev%s %llux broken\n",
- devtab[nc->type]->name, nc->qid.path);
- error("broken devgen");
- }
- nc->qid = dir.qid;
- goto Accept;
- }
- /*
- * Ugly problem: If we're using devgen, make sure we're
- * walking the directory itself, represented by the first
- * entry in the table, and not trying to step into a sub-
- * directory of the table, e.g. /net/net. Devgen itself
- * should take care of the problem, but it doesn't have
- * the necessary information (that we're doing a walk).
- */
- if(gen==devgen && nc->qid.path!=tab[0].qid.path)
- goto Notfound;
- for(i=0;; i++) {
- switch((*gen)(nc, n, tab, ntab, i, &dir)){
- case -1:
- Notfound:
- if(j == 0)
- error(Enonexist);
- kstrcpy(up->errstr, 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, nil, tab, ntab, i, &dir)){
- case -1:
- if(c->qid.type & QTDIR){
- if(c->path == nil)
- elem = "???";
- else if(strcmp(c->path->s, "/") == 0)
- elem = "/";
- else
- for(elem=p=c->path->s; *p; p++)
- if(*p == '/')
- elem = p+1;
- devdir(c, c->qid, elem, 0, eve, DMDIR|0555, &dir);
- n = convD2M(&dir, db, n);
- if(n == 0)
- error(Ebadarg);
- return n;
- }
- error(Enonexist);
- case 0:
- break;
- case 1:
- if(c->qid.path == dir.qid.path) {
- if(c->flag&CMSG)
- dir.mode |= DMMOUNT;
- n = convD2M(&dir, db, n);
- if(n == 0)
- error(Ebadarg);
- return n;
- }
- break;
- }
- }
- }
- long
- devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
- {
- long m, dsz;
- Dir dir;
- for(m=0; m<n; c->dri++) {
- switch((*gen)(c, nil, tab, ntab, c->dri, &dir)){
- case -1:
- return m;
- case 0:
- 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)
- error(Eshort);
- 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, nil, 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 *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;
- }
- long
- devbwrite(Chan *c, Block *bp, ulong offset)
- {
- long n;
- if(waserror()) {
- freeb(bp);
- nexterror();
- }
- n = devtab[c->type]->write(c, bp->rp, BLEN(bp), offset);
- poperror();
- freeb(bp);
- return n;
- }
- void
- devremove(Chan*)
- {
- error(Eperm);
- }
- int
- devwstat(Chan*, uchar*, int)
- {
- error(Eperm);
- return 0;
- }
- void
- devpower(int)
- {
- error(Eperm);
- }
- int
- devconfig(int, char *, DevConf *)
- {
- error(Eperm);
- return 0;
- }
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