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ITS#6437, fixes for stack implementation of slap_sl_realloc():

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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).
This commit is contained in:
Hallvard Furuseth 2010-01-02 21:39:46 +00:00
parent 5b164ba74c
commit cc58227437
1 changed files with 31 additions and 24 deletions
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55
servers/slapd/sl_malloc.c
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@ -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