Merge pull request #98 from devnexen/reallocarray

reallocarray interface.

Author: struct

include/iso_alloc.h

@@ -33,6 +33,7 @@ extern "C" {
 EXTERNAL_API NO_DISCARD MALLOC_ATTR ALLOC_SIZE ASSUME_ALIGNED void *iso_alloc(size_t size);
 EXTERNAL_API NO_DISCARD MALLOC_ATTR CALLOC_SIZE ASSUME_ALIGNED void *iso_calloc(size_t nmemb, size_t size);
 EXTERNAL_API NO_DISCARD MALLOC_ATTR REALLOC_SIZE ASSUME_ALIGNED void *iso_realloc(void *p, size_t size);
+EXTERNAL_API NO_DISCARD MALLOC_ATTR REALLOC_SIZE ASSUME_ALIGNED void *iso_reallocarray(void *p, size_t nmemb, size_t size);
 EXTERNAL_API void iso_free(void *p);
 EXTERNAL_API void iso_free_size(void *p, size_t size);
 EXTERNAL_API void iso_free_permanently(void *p);

src/iso_alloc_interfaces.c

@@ -69,6 +69,16 @@ EXTERNAL_API NO_DISCARD REALLOC_SIZE ASSUME_ALIGNED void *iso_realloc(void *p, s
     return r;
 }
 
+EXTERNAL_API NO_DISCARD MALLOC_ATTR REALLOC_SIZE ASSUME_ALIGNED void *iso_reallocarray(void *p, size_t nmemb, size_t size) {
+    unsigned int res;
+
+    if(__builtin_umul_overflow(nmemb, size, &res)) {
+        return NULL;
+    }
+
+    return iso_realloc(p, nmemb * size);
+}
+
 EXTERNAL_API NO_DISCARD ASSUME_ALIGNED char *iso_strdup(const char *str) {
     return iso_strdup_from_zone(NULL, str);
 }

src/malloc_hook.c

@@ -45,6 +45,14 @@ EXTERNAL_API void *realloc(void *p, size_t s) {
     return iso_realloc(p, s);
 }
 
+EXTERNAL_API void *__libc_reallocarray(void *p, size_t n, size_t s) {
+    return iso_reallocarray(p, n, s);
+}
+
+EXTERNAL_API void *reallocarray(void *p, size_t n, size_t s) {
+    return iso_reallocarray(p, n, s);
+}
+
 EXTERNAL_API int __posix_memalign(void **r, size_t a, size_t s) {
     /* All iso_alloc allocations are 8 byte aligned */
     *r = iso_alloc(s);

tests/interfaces_test.c

@@ -38,6 +38,17 @@ int main(int argc, char *argv[]) {
         LOG_AND_ABORT("iso_realloc failed")
     }
 
+    /* Test iso_reallocarray */
+    if(iso_reallocarray(NULL, SIZE_MAX, SIZE_MAX) != NULL) {
+        LOG_AND_ABORT("iso_reallocarray should have overflown");
+    }
+
+    p = iso_reallocarray(p, 16, 16);
+
+    if(p == NULL) {
+        LOG_AND_ABORT("iso_reallocarray failed")
+    }
+
     iso_free(p);
 
     p = iso_alloc(1024);