zoukankan      html  css  js  c++  java
  • glibc的malloc钩子

    调试C程序内存泄露,在腾讯游戏的分享中也是用的这个方法

    __malloc_hook(3) - Linux man page

    Name

    __malloc_hook, __malloc_initialize_hook, __memalign_hook, __free_hook, __realloc_hook, __after_morecore_hook - malloc debugging variables
    Synopsis

    include <malloc.h>

    void (__malloc_hook)(size_t size, const void *caller);
    void (__realloc_hook)(void *ptr, size_t size", const void *" caller );

    void (__memalign_hook)(size_t alignment, size_t size,
    const void caller);
    void (
    __free_hook)(void ptr, const void caller);
    void (
    __malloc_initialize_hook)(void);
    void (
    __after_morecore_hook)(void);
    Description

    The GNU C library lets you modify the behavior of malloc(3), realloc(3), and free(3) by specifying appropriate hook functions. You can use these hooks to help you debug programs that use dynamic memory allocation, for example.
    The variable __malloc_initialize_hook points at a function that is called once when the malloc implementation is initialized. This is a weak variable, so it can be overridden in the application with a definition like the following:

    void (*__malloc_initialize_hook)(void) = my_init_hook;
    Now the function my_init_hook() can do the initialization of all hooks.
    The four functions pointed to by __malloc_hook, __realloc_hook, __memalign_hook, __free_hook have a prototype like the functions malloc(3), realloc(3), memalign(3), free(3), respectively, except that they have a final argument caller that gives the address of the caller of malloc(3), etc.

    The variable __after_morecore_hook points at a function that is called each time after sbrk(2) was asked for more memory.

    Conforming to

    These functions are GNU extensions.
    Notes

    The use of these hook functions is not safe in multithreaded programs, and they are now deprecated. Programmers should instead preempt calls to the relevant functions by defining and exporting functions such as "malloc" and "free".
    Example

    Here is a short example of how to use these variables.

    include <stdio.h>

    include <malloc.h>

    /* Prototypes for our hooks. */
    static void my_init_hook(void);
    static void *my_malloc_hook(size_t, const void );
    /
    Variables to save original hooks. */
    static void (old_malloc_hook)(size_t, const void );
    /
    Override initializing hook from the C library. /
    void (
    __malloc_initialize_hook) (void) = my_init_hook;
    static void
    my_init_hook(void)
    {
    old_malloc_hook = __malloc_hook;
    __malloc_hook = my_malloc_hook;
    }
    static void *
    my_malloc_hook(size_t size, const void *caller)
    {
    void result;
    /
    Restore all old hooks /
    __malloc_hook = old_malloc_hook;
    /
    Call recursively /
    result = malloc(size);
    /
    Save underlying hooks /
    old_malloc_hook = __malloc_hook;
    /
    printf() might call malloc(), so protect it too. /
    printf("malloc(%u) called from %p returns %p ",
    (unsigned int) size, caller, result);
    /
    Restore our own hooks */
    __malloc_hook = my_malloc_hook;
    return result;
    }

  • 相关阅读:
    “TensorFlow 开发者出道计划”全攻略,玩转社区看这里!
    魔改合成大西瓜
    自定义注解!绝对是程序员装逼的利器!!
    Python中的join()函数的用法
    Python中的split()函数的用法
    linux 完全卸载mysql数据库
    域名被盗后还能不能找回
    在选择域名后缀时应该考虑到的问题
    什么叫域名劫持 和域名解析有什么区别
    河北重大技术需求系统04
  • 原文地址:https://www.cnblogs.com/encode/p/9982921.html
Copyright © 2011-2022 走看看