From 3cb6f9dad7e37db865bd3cbccf0b5d6471fdd73f Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Tue, 28 May 2019 19:49:06 +0300
Subject: [PATCH] backported malloc fixes from 256boss, plus the addition of
 calloc and realloc

---
 src/libc/malloc.c |   44 ++++++++++++++++++++++++++++++++++++++++++--
 src/libc/stdlib.h |    2 ++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/libc/malloc.c b/src/libc/malloc.c
index 4e5991d..3610d24 100644
--- a/src/libc/malloc.c
+++ b/src/libc/malloc.c
@@ -15,9 +15,12 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <errno.h>
 #include "mem.h"
+#include "panic.h"
 
 struct mem_desc {
 	size_t size;
@@ -91,6 +94,7 @@ void *malloc(size_t sz)
 				add_to_pool(other);
 			}
 
+			mem->magic = MAGIC;
 			return DESC_PTR(mem);
 		}
 
@@ -119,6 +123,10 @@ void free(void *p)
 	int pg0;
 	struct mem_desc *mem = PTR_DESC(p);
 
+	if(mem->magic != MAGIC) {
+		panic("free: corrupted magic!\n");
+	}
+
 	if(mem->size > MAX_POOL_SIZE) {
 		/*printf("foo_free(%p): %ld bytes. block too large for pools, returning to system\n",
 				(void*)p, (unsigned long)mem->size);*/
@@ -131,6 +139,38 @@ void free(void *p)
 	add_to_pool(mem);
 }
 
+
+void *calloc(size_t num, size_t size)
+{
+	void *ptr = malloc(num * size);
+	if(ptr) {
+		memset(ptr, 0, num * size);
+	}
+	return ptr;
+}
+
+void *realloc(void *ptr, size_t size)
+{
+	struct mem_desc *mem;
+	void *newp;
+
+	if(!ptr) {
+		return malloc(size);
+	}
+
+	mem = PTR_DESC(ptr);
+	if(mem->size >= size) {
+		return ptr;	/* TODO: shrink */
+	}
+
+	if(!(newp = malloc(size))) {
+		return 0;
+	}
+	free(ptr);
+	return newp;
+}
+
+
 static int add_to_pool(struct mem_desc *mem)
 {
 	int pidx;
@@ -148,7 +188,7 @@ static int add_to_pool(struct mem_desc *mem)
 		pnode = iter->next;
 		if(mem->size == pnode->size) {	/* only coalesce same-sized blocks */
 			if((char*)mem == (char*)pnode - pnode->size) {
-				iter = pnode->next;	/* unlink pnode */
+				iter->next = pnode->next;	/* unlink pnode */
 				pools[pidx] = head.next;
 				mem->next = 0;
 				mem->size += pnode->size;
@@ -157,7 +197,7 @@ static int add_to_pool(struct mem_desc *mem)
 				return add_to_pool(mem);
 			}
 			if((char*)mem == (char*)pnode + pnode->size) {
-				iter = pnode->next;	/* unlink pnode */
+				iter->next = pnode->next;	/* unlink pnode */
 				pools[pidx] = head.next;
 				pnode->next = 0;
 				pnode->size += mem->size;
diff --git a/src/libc/stdlib.h b/src/libc/stdlib.h
index 422792a..9a0eab4 100644
--- a/src/libc/stdlib.h
+++ b/src/libc/stdlib.h
@@ -32,6 +32,8 @@ void utoa(unsigned int val, char *buf, int base);
 
 /* defined in malloc.c */
 void *malloc(size_t sz);
+void *calloc(size_t num, size_t sz);
+void *realloc(void *ptr, size_t sz);
 void free(void *ptr);
 
 #endif	/* STDLIB_H_ */
-- 
1.7.10.4