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- If (keysize+datasize)%(bsize=14)==0, insertion of a `big key' would cause

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an invariant (actually, an ugly hack) to fail, and all Hell would break
   loose.

   When deleting a big key, the offset of an empty page should be bsize, not
   bsize-1; otherwise an insertion into the empty page will cause the new key to
   be elongated by 1 byte.

   Make the packing more dense in a couple of cases.

 - fix NULL dereference exposed on big bsize values;

Obtained from:	NetBSD via OpenBSD
This commit is contained in:
Xin LI 2009-03-28 06:47:05 +00:00
parent 4524c90576
commit a47fc82519
1 changed files with 18 additions and 6 deletions
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24
lib/libc/db/hash/hash_bigkey.c
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@ -118,18 +118,30 @@ __big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
return (-1);
n = p[0];
if (!key_size) {
if (FREESPACE(p)) {
move_bytes = MIN(FREESPACE(p), val_size);
space = FREESPACE(p);
if (space) {
move_bytes = MIN(space, val_size);
/*
* If the data would fit exactly in the
* remaining space, we must overflow it to the
* next page; otherwise the invariant that the
* data must end on a page with FREESPACE
* non-zero would fail.
*/
if (space == val_size && val_size == val->size)
goto toolarge;
off = OFFSET(p) - move_bytes;
p[n] = off;
memmove(cp + off, val_data, move_bytes);
val_data += move_bytes;
val_size -= move_bytes;
p[n] = off;
p[n - 2] = FULL_KEY_DATA;
FREESPACE(p) = FREESPACE(p) - move_bytes;
OFFSET(p) = off;
} else
} else {
toolarge:
p[n - 2] = FULL_KEY;
}
}
p = (u_int16_t *)bufp->page;
cp = bufp->page;
@ -239,12 +251,12 @@ __big_delete(HTAB *hashp, BUFHEAD *bufp)
n -= 2;
bp[0] = n;
FREESPACE(bp) = hashp->BSIZE - PAGE_META(n);
OFFSET(bp) = hashp->BSIZE - 1;
OFFSET(bp) = hashp->BSIZE;
bufp->flags |= BUF_MOD;
if (rbufp)
__free_ovflpage(hashp, rbufp);
if (last_bfp != rbufp)
if (last_bfp && last_bfp != rbufp)
__free_ovflpage(hashp, last_bfp);
hashp->NKEYS--;