diff options
Diffstat (limited to 'src/common/memarea.c')
| -rw-r--r-- | src/common/memarea.c | 45 |
1 files changed, 38 insertions, 7 deletions
diff --git a/src/common/memarea.c b/src/common/memarea.c index edd7bbe9ef..dac15434c0 100644 --- a/src/common/memarea.c +++ b/src/common/memarea.c @@ -11,7 +11,11 @@ #include "memarea.h" #include "util.h" #include "compat.h" -#include "log.h" +#include "torlog.h" + +/** If true, we try to detect any attempts to write beyond the length of a + * memarea. */ +#define USE_SENTINELS /** All returned pointers should be aligned to the nearest multiple of this * value. */ @@ -25,6 +29,24 @@ #error "void* is neither 4 nor 8 bytes long. I don't know how to align stuff." #endif +#ifdef USE_SENTINELS +#define SENTINEL_VAL 0x90806622u +#define SENTINEL_LEN sizeof(uint32_t) +#define SET_SENTINEL(chunk) \ + STMT_BEGIN \ + set_uint32( &(chunk)->u.mem[chunk->mem_size], SENTINEL_VAL ); \ + STMT_END +#define CHECK_SENTINEL(chunk) \ + STMT_BEGIN \ + uint32_t sent_val = get_uint32(&(chunk)->u.mem[chunk->mem_size]); \ + tor_assert(sent_val == SENTINEL_VAL); \ + STMT_END +#else +#define SENTINEL_LEN 0 +#define SET_SENTINEL(chunk) STMT_NIL +#define CHECK_SENTINEL(chunk) STMT_NIL +#endif + /** Increment <b>ptr</b> until it is aligned to MEMAREA_ALIGN. */ static INLINE void * realign_pointer(void *ptr) @@ -79,15 +101,20 @@ alloc_chunk(size_t sz, int freelist_ok) freelist = res->next_chunk; res->next_chunk = NULL; --freelist_len; + CHECK_SENTINEL(res); return res; } else { size_t chunk_size = freelist_ok ? CHUNK_SIZE : sz; - memarea_chunk_t *res = tor_malloc_roundup(&chunk_size); + memarea_chunk_t *res; + chunk_size += SENTINEL_LEN; + res = tor_malloc_roundup(&chunk_size); res->next_chunk = NULL; - res->mem_size = chunk_size - CHUNK_HEADER_SIZE; + res->mem_size = chunk_size - CHUNK_HEADER_SIZE - SENTINEL_LEN; res->next_mem = res->u.mem; - tor_assert(res->next_mem+res->mem_size == ((char*)res)+chunk_size); + tor_assert(res->next_mem+res->mem_size+SENTINEL_LEN == + ((char*)res)+chunk_size); tor_assert(realign_pointer(res->next_mem) == res->next_mem); + SET_SENTINEL(res); return res; } } @@ -95,8 +122,9 @@ alloc_chunk(size_t sz, int freelist_ok) /** Release <b>chunk</b> from a memarea, either by adding it to the freelist * or by freeing it if the freelist is already too big. */ static void -chunk_free(memarea_chunk_t *chunk) +chunk_free_unchecked(memarea_chunk_t *chunk) { + CHECK_SENTINEL(chunk); if (freelist_len < MAX_FREELIST_LEN) { ++freelist_len; chunk->next_chunk = freelist; @@ -124,7 +152,7 @@ memarea_drop_all(memarea_t *area) memarea_chunk_t *chunk, *next; for (chunk = area->first; chunk; chunk = next) { next = chunk->next_chunk; - chunk_free(chunk); + chunk_free_unchecked(chunk); } area->first = NULL; /*fail fast on */ tor_free(area); @@ -140,7 +168,7 @@ memarea_clear(memarea_t *area) if (area->first->next_chunk) { for (chunk = area->first->next_chunk; chunk; chunk = next) { next = chunk->next_chunk; - chunk_free(chunk); + chunk_free_unchecked(chunk); } area->first->next_chunk = NULL; } @@ -183,6 +211,7 @@ memarea_alloc(memarea_t *area, size_t sz) memarea_chunk_t *chunk = area->first; char *result; tor_assert(chunk); + CHECK_SENTINEL(chunk); tor_assert(sz < SIZE_T_CEILING); if (sz == 0) sz = 1; @@ -261,6 +290,7 @@ memarea_get_stats(memarea_t *area, size_t *allocated_out, size_t *used_out) size_t a = 0, u = 0; memarea_chunk_t *chunk; for (chunk = area->first; chunk; chunk = chunk->next_chunk) { + CHECK_SENTINEL(chunk); a += CHUNK_HEADER_SIZE + chunk->mem_size; tor_assert(chunk->next_mem >= chunk->u.mem); u += CHUNK_HEADER_SIZE + (chunk->next_mem - chunk->u.mem); @@ -277,6 +307,7 @@ memarea_assert_ok(memarea_t *area) tor_assert(area->first); for (chunk = area->first; chunk; chunk = chunk->next_chunk) { + CHECK_SENTINEL(chunk); tor_assert(chunk->next_mem >= chunk->u.mem); tor_assert(chunk->next_mem <= (char*) realign_pointer(chunk->u.mem+chunk->mem_size)); |