#include <malloc.h>
#include <stdbool.h>
#include <stdlib.h>
/*
1.
rk3326_m2g:/ # cat /proc/2914/maps
b1ed4000-b1ed5000 r-xp 00000000 b3:1b 11159                              /data/malloc_hook  
b1ed5000-b1ed6000 r--p 00000000 b3:1b 11159                              /data/malloc_hook

139|console:/data # ./malloc_hook                                              
malloc(10) call from 0xb1ed4a2c, return 0xec60d000    0xb1ed4a2c-b1ed4000=a2c addr2line addr
free call from 0xec79e88d, free p=0x0
realloc(2048) call from 0xb1ed4a3c, return 0xec60f000,old p=0xec60d000
free call from 0xec79e88d, free p=0x0
free call from 0xb1ed4a48, free p=0xec60f000
free call from 0xb1ed4a60, free p=0xec60d000
2.
bionic/libc/malloc_hooks/tests$ ls
malloc_hooks_tests.cpp

*/
static bool malloc_hook_called_;
static bool free_hook_called_;
static bool realloc_hook_called_;
static bool memalign_hook_called_;

static void *(*orig_malloc_hook_)(size_t, const void *);
static void (*orig_free_hook_)(void *, const void *);
static void *(*orig_realloc_hook_)(void *, size_t, const void *);
static void *(*orig_memalign_hook_)(size_t, size_t, const void *);

static void *test_malloc_hook(size_t, const void *);
static void *test_realloc_hook(void *ptr, size_t, const void *);
static void *test_memalign_hook(size_t, size_t, const void *);
static void test_free_hook(void *, const void *);

void *test_malloc_hook(size_t size, const void *caller)
{
    malloc_hook_called_ = true;
    __malloc_hook = orig_malloc_hook_;
    /*call recursively*/
    void *result = malloc(size);
    /*printf might call malloc, so protect it too*/
    printf("malloc(%u) call from %p, return %p\n", size, caller, result);
    __malloc_hook = test_malloc_hook;
    return result;
}

void *test_realloc_hook(void *ptr, size_t size, const void *caller)
{
    realloc_hook_called_ = true;
    __realloc_hook = orig_realloc_hook_;
    void * result=realloc(ptr,size);
    
    printf("realloc(%u) call from %p, return %p,old p=%p\n", size, caller, result,ptr);
    __realloc_hook = test_realloc_hook;
    return result;
}

void *test_memalign_hook(size_t alignment, size_t size, const void *arg)
{
    memalign_hook_called_ = true;
    
    return orig_memalign_hook_(alignment, size, arg);
}

void test_free_hook(void *ptr, const void *caller)
{
    free_hook_called_ = true;
    __free_hook = orig_free_hook_;
    printf("free call from %p, free p=%p\n", caller, ptr);
    __free_hook = test_free_hook;
    return orig_free_hook_(ptr,caller);// it will free
}

void Init()
{
    malloc_hook_called_ = false;
    free_hook_called_ = false;
    realloc_hook_called_ = false;
    memalign_hook_called_ = false;

    orig_malloc_hook_ = __malloc_hook;
    orig_free_hook_ = __free_hook;
    orig_realloc_hook_ = __realloc_hook;
    orig_memalign_hook_ = __memalign_hook;

    __malloc_hook = test_malloc_hook;
    __free_hook = test_free_hook;
    __realloc_hook = test_realloc_hook;
    __memalign_hook = test_memalign_hook;
}

void Reset()
{
    __malloc_hook = orig_malloc_hook_;
    __free_hook = orig_free_hook_;
    __realloc_hook = orig_realloc_hook_;
    __memalign_hook = orig_memalign_hook_;
}

/*main*/
int main(void)
{
    setenv("LIBC_HOOKS_ENABLE", "1", true);
    char *p;

    Init();
    p = malloc(10);
    //free(p);
    p = realloc(p, 2048);
    free(p);

    p = memalign(32, 1024);
    free(p);
    Reset();
    while(1);
    return 0;
}