void*
egg_secure_alloc_full (const char *tag,
size_t length,
int flags)
{
Block *block;
void *memory = NULL;
if (tag == NULL)
tag = "?";
if (length > 0xFFFFFFFF / 2) {
if (egg_secure_warnings)
fprintf (stderr, "tried to allocate an insane amount of memory: %lu\n",
(unsigned long)length);
return NULL;
}
/* Can't allocate zero bytes */
if (length == 0)
return NULL;
DO_LOCK ();
for (block = all_blocks; block; block = block->next) {
memory = sec_alloc (block, tag, length);
if (memory)
break;
}
/* None of the current blocks have space, allocate new */
if (!memory) {
block = sec_block_create (length, tag);
if (block)
memory = sec_alloc (block, tag, length);
}
#ifdef WITH_VALGRIND
if (memory != NULL)
VALGRIND_MALLOCLIKE_BLOCK (memory, length, sizeof (void*), 1);
#endif
DO_UNLOCK ();
if (!memory && (flags & EGG_SECURE_USE_FALLBACK)) {
memory = egg_memory_fallback (NULL, length);
if (memory) /* Our returned memory is always zeroed */
memset (memory, 0, length);
}
if (!memory)
errno = ENOMEM;
return memory;
}
static void*
sec_realloc (Block *block, void *memory, size_t length)
{
Cell *cell, *other;
word_t *word;
size_t n_words;
size_t valid;
void *alloc;
/* Standard realloc behavior, should have been handled elsewhere */
ASSERT (memory != NULL);
ASSERT (length > 0);
/* Dig out where the meta should be */
word = memory;
--word;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
ASSERT (sec_is_valid_word (block, word));
ASSERT (pool_valid (*word));
cell = *word;
/* Validate that it's actually for real */
sec_check_guards (cell);
ASSERT (cell->allocated > 0);
ASSERT (cell->next == NULL);
ASSERT (cell->prev == NULL);
/* The amount of valid data */
valid = cell->allocated;
/* How many words we actually want */
n_words = sec_size_to_words (length) + 2;
/* Less memory is required than is in the cell */
if (n_words <= cell->n_words) {
/* TODO: No shrinking behavior yet */
cell->allocated = length;
alloc = sec_cell_to_memory (cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (alloc, length);
#endif
/*
* Even though we may be reusing the same cell, that doesn't
* mean that the allocation is shrinking. It could have shrunk
* and is now expanding back some.
*/
if (length < valid)
return sec_clear_memory (alloc, length, valid);
else
return alloc;
}
/* Need braaaaaiiiiiinsss... */
while (cell->n_words < n_words) {
/* See if we have a neighbor who can give us some memory */
other = sec_neighbor_after (block, cell);
if (!other || other->allocated != 0)
break;
/* Eat the whole neighbor if not too big */
if (n_words - cell->n_words + WASTE >= other->n_words) {
cell->n_words += other->n_words;
sec_write_guards (cell);
sec_remove_cell_ring (&block->unused, other);
pool_free (other);
/* Steal from the neighbor */
} else {
other->words += n_words - cell->n_words;
other->n_words -= n_words - cell->n_words;
sec_write_guards (other);
cell->n_words = n_words;
sec_write_guards (cell);
}
}
if (cell->n_words >= n_words) {
cell->allocated = length;
alloc = sec_cell_to_memory (cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (alloc, length);
#endif
return sec_clear_memory (alloc, valid, length);
}
/* That didn't work, try alloc/free */
alloc = sec_alloc (block, length);
if (alloc) {
memcpy (alloc, memory, valid);
sec_free (block, memory);
}
return alloc;
}
