/*
* returns a locked file structure
*/
File*
filep(Chan *cp, uint32_t fid, int flag)
{
File *f;
int h;
if(fid == NOFID)
return 0;
h = (int32_t)(uintptr)cp + fid;
if(h < 0)
h = ~h;
h %= nelem(flist);
loop:
lock(&flock);
for(f=flist[h]; f; f=f->next)
if(f->fid == fid && f->cp == cp){
/*
* Already in use is an error
* when called from attach or clone (walk
* in 9P2000). The console uses FID[12] and
* never clunks them so catch that case.
*/
if(flag == 0 || cp == cons.chan)
goto out;
unlock(&flock);
return 0;
}
if(flag) {
f = newfp();
if(f) {
f->fid = fid;
f->cp = cp;
f->wpath = 0;
f->tlock = 0;
f->doffset = 0;
f->dslot = 0;
f->auth = 0;
f->next = flist[h];
flist[h] = f;
goto out;
}
}
unlock(&flock);
return 0;
out:
unlock(&flock);
qlock(f);
if(f->fid == fid && f->cp == cp)
return f;
qunlock(f);
goto loop;
}
/*
* returns a locked file structure
*/
File*
filep(Chan *cp, int fid, int flag)
{
File *f, *prev;
if(fid == NOF)
return 0;
loop:
lock(&cp->flock);
for(prev=0,f=cp->flist; f; prev=f,f=f->next) {
if(f->fid != fid)
continue;
if(prev) {
prev->next = f->next;
f->next = cp->flist;
cp->flist = f;
}
goto out;
}
if(flag) {
f = newfp(cp);
if(f) {
f->fid = fid;
goto out;
}
}
else print("cannot find %p.%d (list=%p)\n", cp, fid, cp->flist);
unlock(&cp->flock);
return 0;
out:
unlock(&cp->flock);
qlock(f);
if(f->fid != fid) {
qunlock(f);
goto loop;
}
return f;
}