OrionLibC

diff --git a/include/stdlib.h b/include/stdlib.h
index b1265c2..7e278b0 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -1,6 +1,8 @@
 #ifndef _STDLIB_H
 #define _STDLIB_H
 
+#include <stddef.h>
+
 #define EXIT_SUCCESS 0
 #define EXIT_FAILURE 1
 
@@ -11,12 +13,13 @@ extern "C" {
 _Noreturn void abort(void);
 int atexit(void (*)(void));
 int atoi(const char *);
-void free(void *);
+void free(void *addr);
 char *getenv(const char *);
-void *malloc(size_t);
+void *malloc(size_t size);
 void *calloc(size_t, size_t);
+void *realloc(void *addr, size_t size);
 _Noreturn void exit(int status);
-int abs(int);
+int abs(int num);
 
 #ifdef __cplusplus
 }
diff --git a/stdlib/malloc.c b/stdlib/malloc.c
index cd19760..2ac9f32 100644
--- a/stdlib/malloc.c
+++ b/stdlib/malloc.c
@@ -130,7 +130,8 @@ malloc(size_t size)
 		/* Attempt to use arena */
 		addr = arena_malloc(arena, size);
 		if (!addr && !arena->next)
-			arena->next = arena_malloc(arena, sizeof(Arena));
+			arena->next = arena->start + arena->size
+			            - sizeof(Arena);
 	}
 
 	return addr;
@@ -155,3 +156,20 @@ free(void *addr)
 	if (next)
 		next->prev = prev;
 }
+
+/* Re-allocate a region of memory */
+void *
+realloc(void *addr, size_t size)
+{
+	void *ptr = malloc(size);
+	if (addr) {
+		Header *old = (Header *) addr - 1;
+		if (memcmp(old->magic, "HEAP", 4)) {
+			printf("realloc(): invalid pointer\n");
+			abort();
+		}
+		memcpy(ptr, addr, old->size);
+		free(addr);
+	}
+	return ptr;
+}