feat: malloc init, thread safety

inc/malloc.h

@@ -3,9 +3,51 @@
 
 # include <stdlib.h>
 # include <unistd.h>
+# include <sys/mman.h>
+# include <pthread.h>
 
-#define PROUT "42\n"
+// TODO Remove me (printf)
+# include <stdio.h>
+
+#define MAX_ALIGNMENT 16
+
+typedef struct s_block t_block;
+typedef struct s_zone t_zone;
+
+struct s_block {
+	size_t size;
+	int free;
+	t_block *next;
+};
+
+struct s_zone {
+	t_block *head;
+	t_zone *next;
+};
+
+typedef struct s_zones {
+	size_t pagesize;
+	size_t max_align;
+	size_t tiny_block_max_size;
+	size_t small_block_max_size;
+	t_zone *tiny_zones;
+	t_zone *small_zones;
+	t_block *large_blocks;
+} t_zones;
+
+extern pthread_mutex_t g_malloc_mutex;
+extern t_zones g_zones;
 
 void *malloc(size_t size);
+void free(void *ptr);
+void *realloc(void *ptr, size_t size);
+
+void show_alloc_mem(void);
+void show_alloc_mem_ex(void);
+void show_alloc_sizes(void);
+
+static void init_malloc(void);
+void init_tiny_zones(void);
+void init_small_zones(void);
 
 #endif

main.c

@@ -1,6 +1,10 @@
 #include <stdlib.h>
+#include "inc/malloc.h"
 
 int main(void) {
-	malloc(42);
+	int *arr = malloc(42);
+	arr = realloc(arr, 42);
+	free(arr);
+	show_alloc_sizes();
 	return 0;
 }

src/free.c

@@ -0,0 +1,7 @@
+#include "malloc.h"
+
+void free(void *ptr) {
+	pthread_mutex_lock(&g_malloc_mutex);
+	(void)ptr;
+	pthread_mutex_unlock(&g_malloc_mutex);
+}

src/init.c

@@ -0,0 +1,26 @@
+#include "malloc.h"
+
+pthread_mutex_t g_malloc_mutex;
+t_zones g_zones;
+
+void init_tiny_zones(void) {
+	g_zones.tiny_block_max_size = g_zones.pagesize / 2;
+	g_zones.tiny_zones = (t_zone *)mmap(NULL, g_zones.tiny_block_max_size * 128, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	g_zones.tiny_zones->head = NULL;
+	g_zones.tiny_zones->next = NULL;
+}
+
+void init_small_zones(void) {
+	g_zones.small_block_max_size = g_zones.tiny_block_max_size * 128;
+	g_zones.small_zones = (t_zone *)mmap(NULL, g_zones.small_block_max_size * 128, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	g_zones.small_zones->head = NULL;
+	g_zones.small_zones->next = NULL;
+}
+
+__attribute__((constructor))
+static void init_malloc(void) {
+	g_zones.pagesize = (size_t)sysconf(_SC_PAGESIZE);
+	g_zones.max_align = MAX_ALIGNMENT;
+	init_tiny_zones();
+	init_small_zones();
+}

src/malloc.c

@@ -1,7 +1,9 @@
 #include "malloc.h"
 
 void *malloc(size_t size) {
+	pthread_mutex_lock(&g_malloc_mutex);
 	(void)size;
-	write(1, PROUT, 3);
+	write(1, "42 from malloc\n", 15);
-	return 0;
+	pthread_mutex_unlock(&g_malloc_mutex);
+	return NULL;
 }

src/realloc.c

@@ -0,0 +1,10 @@
+#include "malloc.h"
+
+void *realloc(void *ptr, size_t size) {
+	pthread_mutex_lock(&g_malloc_mutex);
+	write(1, "1337\n", 5);
+	(void)size;
+	(void)ptr;
+	pthread_mutex_unlock(&g_malloc_mutex);
+	return ptr;
+}

src/utils.c

@@ -0,0 +1,14 @@
+#include "malloc.h"
+
+void show_alloc_mem(void) {
+}
+
+void show_alloc_mem_ex(void) {
+}
+
+void show_alloc_sizes(void) {
+	// TODO remove me (printf)
+	printf("PAGESIZE : %zu bytes\n", g_zones.pagesize);
+	printf("TINY ZONE MAX BLOCK SIZE: %zu bytes\n", g_zones.tiny_block_max_size);
+	printf("SMALL ZONE MAX BLOCK SIZE : %zu bytes\n", g_zones.small_block_max_size);
+}

test.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 make
-gcc main.c -o test_malloc.out
+gcc main.c libft_malloc.so -o malloc_test.out
-LD_PRELOAD=./libft_malloc.so ./test_malloc.out
+LD_LIBRARY_PATH=. LD_PRELOAD=./libft_malloc.so ./malloc_test.out