diff options
| -rw-r--r-- | src/mapalloc.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/src/mapalloc.c b/src/mapalloc.c index a213bfb..afd8443 100644 --- a/src/mapalloc.c +++ b/src/mapalloc.c @@ -24,10 +24,14 @@ static size_t MA_pagesize(void) #endif #define MAPALLOC_EXIT_VALUE (127 + SIGSEGV) +#define PAGES_PER_TRIE (1024) +#define TRIE_SIZE (PAGESIZE * PAGES_PER_TRIE) struct MA_bucket { size_t used; size_t allocated; + void *under; + void *over; }; static void *MA_page_alloc(size_t npages) @@ -54,7 +58,18 @@ static void *MA_page_alloc(size_t npages) static void MA_sigaction(int sig, siginfo_t *si, void *addr) { (void)sig; (void)addr; - fprintf(stderr, "error accessing %p\n", si->si_addr); + + if (addr == NULL) { + fprintf(stderr, "NULL pointer dereference\n"); + } else { + fprintf(stderr, "error accessing %p\n", si->si_addr); + } + _exit(MAPALLOC_EXIT_VALUE); +} + +static void MA_abort(const char *func, void *ptr) +{ + fprintf(stderr, "%s(): invalid pointer %p\n", func, ptr); _exit(MAPALLOC_EXIT_VALUE); } @@ -70,9 +85,16 @@ static void MA_set_sigaction(void) static struct MA_bucket *MA_bucket(void *ptr, int allocate) { - /* FIXME: assumption that one page can hold UCHAR_MAX uintptr_t */ /* FIXME: check return values of page_alloc() */ + /* FIXME: assumption that one page can hold UCHAR_MAX uintptr_t */ + /* + static size_t per_trie = 0; + if (per_trie == 0) { + per_trie = TRIE_SIZE / sizeof(uintptr_t); + } + */ + static uintptr_t *trie_top = NULL; if (trie_top == NULL) { trie_top = MA_page_alloc(1); @@ -125,12 +147,14 @@ void *MA_malloc(size_t nbytes) return NULL; } - mprotect(ptr, PAGESIZE, PROT_NONE); - mprotect(ptr + ((pages - 1) * PAGESIZE), PAGESIZE, PROT_NONE); - struct MA_bucket *b = MA_bucket(ptr + PAGESIZE, 1); b->used = nbytes; b->allocated = pages * PAGESIZE; + b->under = ptr; + b->over = ptr + ((pages - 1) * PAGESIZE); + + mprotect(b->under, PAGESIZE, PROT_NONE); + mprotect(b->over, PAGESIZE, PROT_NONE); return ptr + PAGESIZE; } @@ -143,8 +167,7 @@ void *MA_realloc(void *ptr, size_t n) struct MA_bucket *b = MA_bucket(ptr, 0); if (b == NULL) { - fprintf(stderr, "%s(%p, %zu): invalid pointer\n", __func__, ptr, n); - _exit(MAPALLOC_EXIT_VALUE); + MA_abort(__func__, ptr); } if (n < (b->allocated - (PAGESIZE * 2))) { @@ -169,8 +192,7 @@ void MA_free(void *ptr) struct MA_bucket *b = MA_bucket(ptr, 0); if (b == NULL) { - fprintf(stderr, "%s(%p): invalid pointer\n", __func__, ptr); - _exit(MAPALLOC_EXIT_VALUE); + MA_abort(__func__, ptr); } char *base = ptr; |