469 lines
8.3 KiB
C
469 lines
8.3 KiB
C
#include "u.h"
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#include "lib.h"
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#include "dat.h"
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#include "fns.h"
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#include "error.h"
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extern ulong kerndate;
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void
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mkqid(Qid *q, vlong path, ulong vers, int type)
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{
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q->type = type;
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q->vers = vers;
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q->path = path;
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}
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int
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devno(int c, int user)
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{
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int i;
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for(i = 0; devtab[i] != nil; i++) {
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if(devtab[i]->dc == c)
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return i;
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}
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if(user == 0)
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panic("devno %C 0x%ux", c, c);
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return -1;
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}
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void
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devdir(Chan *c, Qid qid, char *n, vlong length, char *user, long perm, Dir *db)
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{
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db->name = n;
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if(c->flag&CMSG)
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qid.type |= QTMOUNT;
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db->qid = qid;
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db->type = devtab[c->type]->dc;
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db->dev = c->dev;
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db->mode = perm;
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db->mode |= qid.type << 24;
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db->atime = seconds();
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db->mtime = kerndate;
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db->length = length;
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db->uid = user;
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db->gid = eve;
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db->muid = user;
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}
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/*
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* (here, Devgen is the prototype; devgen is the function in dev.c.)
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*
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* a Devgen is expected to return the directory entry for ".."
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* if you pass it s==DEVDOTDOT (-1). otherwise...
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*
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* there are two contradictory rules.
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*
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* (i) if c is a directory, a Devgen is expected to list its children
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* as you iterate s.
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*
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* (ii) whether or not c is a directory, a Devgen is expected to list
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* its siblings as you iterate s.
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*
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* devgen always returns the list of children in the root
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* directory. thus it follows (i) when c is the root and (ii) otherwise.
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* many other Devgens follow (i) when c is a directory and (ii) otherwise.
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*
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* devwalk assumes (i). it knows that devgen breaks (i)
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* for children that are themselves directories, and explicitly catches them.
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*
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* devstat assumes (ii). if the Devgen in question follows (i)
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* for this particular c, devstat will not find the necessary info.
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* with our particular Devgen functions, this happens only for
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* directories, so devstat makes something up, assuming
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* c->name, c->qid, eve, DMDIR|0555.
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*
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* devdirread assumes (i). the callers have to make sure
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* that the Devgen satisfies (i) for the chan being read.
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*/
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/*
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* the zeroth element of the table MUST be the directory itself for ..
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*/
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int
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devgen(Chan *c, char *name, Dirtab *tab, int ntab, int i, Dir *dp)
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{
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if(tab == 0)
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return -1;
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if(i == DEVDOTDOT){
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/* nothing */
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}else if(name){
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for(i=1; i<ntab; i++)
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if(strcmp(tab[i].name, name) == 0)
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break;
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if(i==ntab)
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return -1;
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tab += i;
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}else{
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/* skip over the first element, that for . itself */
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i++;
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if(i >= ntab)
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return -1;
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tab += i;
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}
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devdir(c, tab->qid, tab->name, tab->length, eve, tab->perm, dp);
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return 1;
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}
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void
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devreset(void)
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{
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}
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void
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devinit(void)
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{
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}
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void
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devshutdown(void)
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{
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}
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Chan*
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devattach(int tc, char *spec)
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{
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Chan *c;
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char *buf;
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c = newchan();
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mkqid(&c->qid, 0, 0, QTDIR);
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c->type = devno(tc, 0);
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if(spec == nil)
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spec = "";
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buf = smalloc(4+strlen(spec)+1);
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sprint(buf, "#%C%s", tc, spec);
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c->name = newcname(buf);
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free(buf);
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return c;
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}
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Chan*
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devclone(Chan *c)
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{
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Chan *nc;
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if(c->flag & COPEN)
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panic("clone of open file type %C\n", devtab[c->type]->dc);
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nc = newchan();
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nc->type = c->type;
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nc->dev = c->dev;
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nc->mode = c->mode;
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nc->qid = c->qid;
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nc->offset = c->offset;
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nc->umh = nil;
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nc->mountid = c->mountid;
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nc->aux = c->aux;
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nc->pgrpid = c->pgrpid;
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nc->mid = c->mid;
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nc->mqid = c->mqid;
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nc->mcp = c->mcp;
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return nc;
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}
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Walkqid*
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devwalk(Chan *c, Chan *nc, char **name, int nname, Dirtab *tab, int ntab, Devgen *gen)
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{
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int i, j, alloc;
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Walkqid *wq;
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char *n;
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Dir dir;
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if(nname > 0)
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isdir(c);
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alloc = 0;
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wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid));
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if(waserror()){
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if(alloc && wq->clone!=nil)
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cclose(wq->clone);
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free(wq);
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return nil;
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}
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if(nc == nil){
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nc = devclone(c);
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nc->type = 0; /* device doesn't know about this channel yet */
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alloc = 1;
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}
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wq->clone = nc;
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for(j=0; j<nname; j++){
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if(!(nc->qid.type&QTDIR)){
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if(j==0)
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error(Enotdir);
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goto Done;
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}
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n = name[j];
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if(strcmp(n, ".") == 0){
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Accept:
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wq->qid[wq->nqid++] = nc->qid;
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continue;
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}
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if(strcmp(n, "..") == 0){
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if((*gen)(nc, nil, tab, ntab, DEVDOTDOT, &dir) != 1){
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print("devgen walk .. in dev%s %llux broken\n",
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devtab[nc->type]->name, nc->qid.path);
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error("broken devgen");
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}
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nc->qid = dir.qid;
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goto Accept;
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}
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/*
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* Ugly problem: If we're using devgen, make sure we're
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* walking the directory itself, represented by the first
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* entry in the table, and not trying to step into a sub-
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* directory of the table, e.g. /net/net. Devgen itself
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* should take care of the problem, but it doesn't have
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* the necessary information (that we're doing a walk).
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*/
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if(gen==devgen && nc->qid.path!=tab[0].qid.path)
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goto Notfound;
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for(i=0;; i++) {
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switch((*gen)(nc, n, tab, ntab, i, &dir)){
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case -1:
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Notfound:
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if(j == 0)
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error(Enonexist);
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kstrcpy(up->errstr, Enonexist, ERRMAX);
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goto Done;
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case 0:
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continue;
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case 1:
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if(strcmp(n, dir.name) == 0){
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nc->qid = dir.qid;
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goto Accept;
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}
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continue;
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}
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}
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}
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/*
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* We processed at least one name, so will return some data.
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* If we didn't process all nname entries succesfully, we drop
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* the cloned channel and return just the Qids of the walks.
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*/
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Done:
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poperror();
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if(wq->nqid < nname){
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if(alloc)
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cclose(wq->clone);
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wq->clone = nil;
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}else if(wq->clone){
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/* attach cloned channel to same device */
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wq->clone->type = c->type;
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}
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return wq;
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}
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int
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devstat(Chan *c, uchar *db, int n, Dirtab *tab, int ntab, Devgen *gen)
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{
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int i;
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Dir dir;
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char *p, *elem;
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for(i=0;; i++)
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switch((*gen)(c, nil, tab, ntab, i, &dir)){
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case -1:
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if(c->qid.type & QTDIR){
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if(c->name == nil)
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elem = "???";
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else if(strcmp(c->name->s, "/") == 0)
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elem = "/";
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else
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for(elem=p=c->name->s; *p; p++)
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if(*p == '/')
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elem = p+1;
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devdir(c, c->qid, elem, 0, eve, DMDIR|0555, &dir);
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n = convD2M(&dir, db, n);
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if(n == 0)
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error(Ebadarg);
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return n;
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}
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print("devstat %C %llux\n", devtab[c->type]->dc, c->qid.path);
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error(Enonexist);
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case 0:
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break;
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case 1:
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if(c->qid.path == dir.qid.path) {
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if(c->flag&CMSG)
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dir.mode |= DMMOUNT;
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n = convD2M(&dir, db, n);
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if(n == 0)
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error(Ebadarg);
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return n;
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}
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break;
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}
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error(Egreg); /* not reached? */
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return -1;
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}
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long
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devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
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{
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long m, dsz;
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struct{
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Dir d;
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char slop[100];
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}dir;
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for(m=0; m<n; c->dri++) {
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switch((*gen)(c, nil, tab, ntab, c->dri, &dir.d)){
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case -1:
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return m;
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case 0:
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break;
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case 1:
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dsz = convD2M(&dir.d, (uchar*)d, n-m);
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if(dsz <= BIT16SZ){ /* <= not < because this isn't stat; read is stuck */
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if(m == 0)
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error(Eshort);
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return m;
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}
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m += dsz;
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d += dsz;
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break;
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}
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}
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return m;
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}
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/*
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* error(Eperm) if open permission not granted for up->user.
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*/
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void
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devpermcheck(char *fileuid, ulong perm, int omode)
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{
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ulong t;
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static int access[] = { 0400, 0200, 0600, 0100 };
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if(strcmp(up->user, fileuid) == 0)
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perm <<= 0;
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else
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if(strcmp(up->user, eve) == 0)
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perm <<= 3;
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else
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perm <<= 6;
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t = access[omode&3];
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if((t&perm) != t)
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error(Eperm);
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}
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Chan*
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devopen(Chan *c, int omode, Dirtab *tab, int ntab, Devgen *gen)
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{
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int i;
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Dir dir;
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for(i=0;; i++) {
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switch((*gen)(c, nil, tab, ntab, i, &dir)){
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case -1:
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goto Return;
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case 0:
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break;
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case 1:
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if(c->qid.path == dir.qid.path) {
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devpermcheck(dir.uid, dir.mode, omode);
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goto Return;
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}
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break;
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}
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}
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Return:
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c->offset = 0;
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if((c->qid.type&QTDIR) && omode!=OREAD)
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error(Eperm);
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c->mode = openmode(omode);
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c->flag |= COPEN;
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return c;
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}
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void
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devcreate(Chan *c, char *name, int mode, ulong perm)
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{
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USED(c);
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USED(name);
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USED(mode);
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USED(perm);
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error(Eperm);
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}
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Block*
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devbread(Chan *c, long n, ulong offset)
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{
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Block *bp;
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bp = allocb(n);
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if(bp == 0)
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error(Enomem);
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if(waserror()) {
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freeb(bp);
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nexterror();
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}
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bp->wp += devtab[c->type]->read(c, bp->wp, n, offset);
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poperror();
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return bp;
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}
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long
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devbwrite(Chan *c, Block *bp, ulong offset)
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{
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long n;
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if(waserror()) {
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freeb(bp);
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nexterror();
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}
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n = devtab[c->type]->write(c, bp->rp, BLEN(bp), offset);
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poperror();
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freeb(bp);
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return n;
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}
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void
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devremove(Chan *c)
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{
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USED(c);
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error(Eperm);
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}
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int
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devwstat(Chan *c, uchar *a, int n)
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{
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USED(c);
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USED(a);
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USED(n);
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error(Eperm);
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return 0;
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}
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void
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devpower(int a)
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{
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USED(a);
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error(Eperm);
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}
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int
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devconfig(int a, char *b, DevConf *c)
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{
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USED(a);
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USED(b);
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USED(c);
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error(Eperm);
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return 0;
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}
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