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authorJakob Kaivo <jkk@ung.org>2020-06-30 16:48:42 -0400
committerJakob Kaivo <jkk@ung.org>2020-06-30 16:48:42 -0400
commitf94c3b213545868bfb9e353aa926071f303eb9d8 (patch)
tree81dbf36bd5ca5b6f10839bfe6871ba0e4465d4ab
parent543c1d44711c4a4cd1ee52c3717abfe2c79b344a (diff)
add MA_abort() to unify undefined behavior path
-rw-r--r--src/mapalloc.c40
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;