Simple C implementation to track memory malloc/free?

You could allocate a few extra bytes in your wrapper and put either an id (if you want to be able to couple malloc() and free()) or just the size there. Just malloc() that much more memory, store the information at the beginning of your memory block and and move the pointer you return that many bytes forward.

This can, btw, also easily be used for fence pointers/finger-prints and such.

Either you can have access to internal tables used by malloc/free (see this question: Where Do malloc() / free() Store Allocated Sizes and Addresses? for some hints), or you have to manage your own tables in your wrappers.

You could always use valgrind instead of rolling your own implementation. If you don't care about the amount of memory you allocate you could use an even simpler implementation: (I did this really quickly so there could be errors and I realize that it is not the most efficient implementation. The pAllocedStorage should be given an initial size and increase by some factor for a resize etc. but you get the idea.)

EDIT: I missed that this was for ARM, to my knowledge valgrind is not available on ARM so that might not be an option.

static size_t indexAllocedStorage = 0;
static size_t *pAllocedStorage = NULL;
static unsigned int free_calls = 0; 
static unsigned long long int total_mem_alloced = 0; 

void * 
my_malloc(size_t size){
    size_t *temp;
    void *p = malloc(size);
    if(p == NULL){
    fprintf(stderr,"my_malloc malloc failed, %s", strerror(errno));
    exit(EXIT_FAILURE);
    }

    total_mem_alloced += size;

    temp = (size_t *)realloc(pAllocedStorage, (indexAllocedStorage+1) * sizeof(size_t));
    if(temp == NULL){
        fprintf(stderr,"my_malloc realloc failed, %s", strerror(errno));
         exit(EXIT_FAILURE);
    }

    pAllocedStorage = temp; 
    pAllocedStorage[indexAllocedStorage++] = (size_t)p;

    return p;
}

void 
my_free(void *p){
    size_t i;
    int found = 0;

    for(i = 0; i < indexAllocedStorage; i++){
    if(pAllocedStorage[i] == (size_t)p){
        pAllocedStorage[i] = (size_t)NULL;
        found = 1;
        break;
        }
    }

    if(!found){
        printf("Free Called on unknown\n");
    }

    free_calls++;
    free(p);
}

void 
free_check(void) {
    size_t i;

    printf("checking freed memeory\n");
    for(i = 0; i < indexAllocedStorage; i++){   
        if(pAllocedStorage[i] != (size_t)NULL){
            printf( "Memory leak %X\n", (unsigned int)pAllocedStorage[i]);
            free((void *)pAllocedStorage[i]);
        }
    }

    free(pAllocedStorage);
    pAllocedStorage = NULL;
}