From 532dff1d641f04e166e37a1d2d6124b69d9d6c72 Mon Sep 17 00:00:00 2001
From: Hallvard Furuseth <hallvard@openldap.org>
Date: Sat, 2 Jan 2010 21:39:46 +0000
Subject: [PATCH] ITS#6437, fixes for stack implementation of
slap_sl_realloc(): Preserve 2*int alignment on hosts where sizeof(int) ==
sizeof(ber_len_t). If realloc of last block falls back to ch_malloc, free
last block properly. Fix range check (ptr + size < endptr) --> (size < endptr
- ptr).
---
servers/slapd/sl_malloc.c | 55 ++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 24 deletions(-)
diff --git a/servers/slapd/sl_malloc.c b/servers/slapd/sl_malloc.c
index a3159b2434..ead25a7317 100644
--- a/servers/slapd/sl_malloc.c
+++ b/servers/slapd/sl_malloc.c
@@ -337,7 +337,8 @@ void *
slap_sl_realloc(void *ptr, ber_len_t size, void *ctx)
{
struct slab_heap *sh = ctx;
- ber_len_t *p = (ber_len_t *)ptr, *newptr;
+ ber_len_t oldsize, *p = (ber_len_t *) ptr;
+ void *newptr;
if (ptr == NULL)
return slap_sl_malloc(size, ctx);
@@ -367,6 +368,8 @@ slap_sl_realloc(void *ptr, ber_len_t size, void *ctx)
return NULL;
}
+ oldsize = p[-1];
+
if (sh->sh_stack) {
/* Round up to doubleword boundary, add room for head */
size = ((size + Align-1) & -Align) + sizeof( ber_len_t );
@@ -374,37 +377,41 @@ slap_sl_realloc(void *ptr, ber_len_t size, void *ctx)
p--;
/* Never shrink blocks */
- if (size <= p[0]) {
- newptr = ptr;
+ if (size <= oldsize) {
+ return ptr;
- /* If reallocing the last block, we can grow it */
- } else if ((char *)ptr + p[0] == sh->sh_last &&
- (char *)ptr + size < (char *)sh->sh_end ) {
- newptr = ptr;
- sh->sh_last = (char *)ptr + size;
- p[0] = size;
- p[size/sizeof(ber_len_t)] = size;
+ /* If reallocing the last block, try to grow it */
+ } else if ((char *) ptr + oldsize == sh->sh_last) {
+ if (size < (char *) sh->sh_end - (char *) ptr) {
+ sh->sh_last = (char *) ptr + size;
+ p[0] = size;
+ p[size/sizeof(ber_len_t)] = size;
+ return ptr;
+ }
/* Nowhere to grow, need to alloc and copy */
} else {
- newptr = slap_sl_malloc(size-sizeof(ber_len_t), ctx);
- AC_MEMCPY(newptr, ptr, p[0]-sizeof(ber_len_t));
- /* mark old region as free */
+ /* Slight optimization of the final realloc variant */
+ size -= sizeof(ber_len_t);
+ oldsize -= sizeof(ber_len_t);
+ newptr = slap_sl_malloc(size, ctx);
+ AC_MEMCPY(newptr, ptr, oldsize);
+ /* Not last block, can just mark old region as free */
p[p[0]/sizeof(ber_len_t)] |= 1;
+ return newptr;
}
- return newptr;
- } else {
- void *newptr2;
- newptr2 = slap_sl_malloc(size, ctx);
- if (size < p[-1]) {
- AC_MEMCPY(newptr2, ptr, size);
- } else {
- AC_MEMCPY(newptr2, ptr, p[-1]);
- }
- slap_sl_free(ptr, ctx);
- return newptr2;
+ size -= sizeof(ber_len_t);
+ oldsize -= sizeof(ber_len_t);
+
+ } else if (oldsize > size) {
+ oldsize = size;
}
+
+ newptr = slap_sl_malloc(size, ctx);
+ AC_MEMCPY(newptr, ptr, oldsize);
+ slap_sl_free(ptr, ctx);
+ return newptr;
}
void
--
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