ref: caf8df647886963848a2e266124de54fcc737247
dir: /sys/src/cmd/vnc/dev.c/
#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; }