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fix unbounded recursion bug in hjfs

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This commit is contained in:
aiju 2018-08-20 14:26:19 +01:00
parent c8a71691b4
commit 4a120a3816
1 changed files with 47 additions and 23 deletions
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70
sys/src/cmd/hjfs/dump.c
View file

@ -112,8 +112,8 @@ err:
return -1;
}
int
willmodify(Fs *fs, Loc *l, int nolock)
static int
willmodify1(Fs *fs, Loc *l)
{
Buf *p;
Loc *m;
@ -121,29 +121,20 @@ willmodify(Fs *fs, Loc *l, int nolock)
Dentry *d;
int rc;
if((l->flags & LDUMPED) != 0)
return 1;
if(!nolock){
again:
runlock(fs);
wlock(fs);
}
if(l->next != nil && willmodify(fs, l->next, 1) < 0)
goto err;
rc = chref(fs, l->blk, 0);
if(rc < 0)
goto err;
return -1;
if(rc == 0){
dprint("willmodify: block %lld has refcount 0\n", l->blk);
werrstr("phase error -- willmodify");
goto err;
return -1;
}
if(rc == 1)
goto done;
p = getbuf(fs->d, l->next->blk, TDENTRY, 0);
if(p == nil)
goto err;
return -1;
d = getdent(l->next, p);
if(d != nil) for(i = 0; i < d->size; i++){
rc = getblk(fs, l->next, p, i, &r, GBREAD);
@ -155,12 +146,12 @@ again:
phase:
werrstr("willmodify -- phase error");
putbuf(p);
goto err;
return -1;
found:
rc = getblk(fs, l->next, p, i, &r, GBWRITE);
if(rc < 0){
putbuf(p);
goto err;
return -1;
}
if(rc == 0)
goto phase;
@ -180,17 +171,50 @@ found:
}
done:
l->flags |= LDUMPED;
return 0;
}
int
willmodify(Fs *fs, Loc *l, int nolock)
{
Loc **st;
int sti, rc;
if((l->flags & LDUMPED) != 0)
return 1;
if(!nolock){
again:
runlock(fs);
wlock(fs);
}
st = emalloc(sizeof(Loc *));
*st = l;
sti = 0;
for(;;){
if((st[sti]->flags & LDUMPED) != 0 || st[sti]->next == nil)
break;
st = erealloc(st, (sti + 2) * sizeof(Loc *));
st[sti + 1] = st[sti]->next;
sti++;
}
rc = 0;
for(; sti >= 0; sti--){
rc = willmodify1(fs, st[sti]);
if(rc < 0){
free(st);
if(!nolock){
wunlock(fs);
rlock(fs);
}
return -1;
}
}
if(!nolock){
wunlock(fs);
rlock(fs);
if(chref(fs, l->blk, 0) != 1)
goto again;
}
return 0;
err:
if(!nolock){
wunlock(fs);
rlock(fs);
}
return -1;
free(st);
return rc;
}