【Linux进程（六）】程序地址空间深度实证：从内存布局验证到虚拟化理解的基石

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文章目录

[5 ~> 程序 / 进程虚拟地址空间](#5 ~> 程序 / 进程虚拟地址空间)
- [5.1 研究平台](#5.1 研究平台)
- [5.2 回顾程序地址空间](#5.2 回顾程序地址空间)
- [5.3 对程序地址空间各个区域进行分布验证](#5.3 对程序地址空间各个区域进行分布验证)
- - [5.3.1 代码演示](#5.3.1 代码演示)
  - [5.3.2 运行结果](#5.3.2 运行结果)
  - [5.3.3 两个问题探究](#5.3.3 两个问题探究)
  - - [5.3.3.1 问题1：`char *s ="hello world";*s = 'H"`为什么不可以修改？](#5.3.3.1 问题1：char *s ="hello world";*s = 'H"为什么不可以修改？)
    - [5.3.3.2 问题2：static（静态）修饰局部变量：作用域不变，生命周期变成全局（？）](#5.3.3.2 问题2：static（静态）修饰局部变量：作用域不变，生命周期变成全局（？）)
- [5.3 程序地址空间初识思维导图](#5.3 程序地址空间初识思维导图)
结尾

5 ~> 程序 / 进程虚拟地址空间

堆、栈相对而生！

堆就是堆，栈就是栈，堆栈是栈。

5.1 研究平台

5.2 回顾程序地址空间

艾莉丝在介绍C语言部分的时候，应该给大家展示过这样的空间布局图------

之前可能是这样一张图------

5.3 对程序地址空间各个区域进行分布验证

但是其实我们对它并不理解，所以，为了铺垫下面的内容，我们先对程序地址空间各个区域进行分布验证------

5.3.1 代码演示

c 复制代码

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

int g_unval;
int g_val = 100;

int main(int argc, char *argv[], char *env[])
{
    const char *str = "helloworld";
    //*str = 'H';
    printf("code addr: %p\n", main);
    printf("init global addr: %p\n", &g_val);
    printf("uninit global addr: %p\n", &g_unval);

    static int test = 10;
    char *heap_mem = (char*)malloc(10);
    char *heap_mem1 = (char*)malloc(10);
    char *heap_mem2 = (char*)malloc(10);
    char *heap_mem3 = (char*)malloc(10);
    printf("heap addr: %p\n", heap_mem); //heap_mem(0), &heap_mem(1)
    printf("heap addr: %p\n", heap_mem1); //heap_mem(0), &heap_mem(1)
    printf("heap addr: %p\n", heap_mem2); //heap_mem(0), &heap_mem(1)
    printf("heap addr: %p\n", heap_mem3); //heap_mem(0), &heap_mem(1)

    printf("test static addr: %p\n", &test); //heap_mem(0), &heap_mem(1)
    printf("stack addr: %p\n", &heap_mem); //heap_mem(0), &heap_mem(1)
    printf("stack addr: %p\n", &heap_mem1); //heap_mem(0), &heap_mem(1)
    printf("stack addr: %p\n", &heap_mem2); //heap_mem(0), &heap_mem(1)
    printf("stack addr: %p\n", &heap_mem3); //heap_mem(0), &heap_mem(1)

    printf("read only string addr: %p\n", str);
    for(int i = 0 ;i < argc; i++)
    {
        printf("argv[%d]: %p\n", i, argv[i]);
    }
    for(int i = 0; env[i]; i++)
    {
        printf("env[%d]: %p\n", i, env[i]);
    }

    return 0;
}

//#include <stdio.h>
//#include <unistd.h>
//#include <stdlib.h>
//
//int g_unval;
//int g_val = 100;
//
//int main(int argc, char *argv[], char *env[])
//{
//    const char *str = "helloworld";
//    printf("code addr: %p\n", main);
//    printf("init global addr: %p\n", &g_val);
//    printf("uninit global addr: %p\n", &g_unval);
//    
//    static int test = 10;
//    char *heap_mem = (char*)malloc(10);
//    char *heap_mem1 = (char*)malloc(10);
//    char *heap_mem2 = (char*)malloc(10);
//    char *heap_mem3 = (char*)malloc(10);
//    printf("heap addr: %p\n", heap_mem); //heap_mem(0), &heap_mem(1)
//    printf("heap addr: %p\n", heap_mem1); //heap_mem(0), &heap_mem(1)
//    printf("heap addr: %p\n", heap_mem2); //heap_mem(0), &heap_mem(1)
//    printf("heap addr: %p\n", heap_mem3); //heap_mem(0), &heap_mem(1)
//    
//    printf("test static addr: %p\n", &test); //heap_mem(0), &heap_mem(1)
//    printf("stack addr: %p\n", &heap_mem); //heap_mem(0), &heap_mem(1)
//    printf("stack addr: %p\n", &heap_mem1); //heap_mem(0), &heap_mem(1)
//    printf("stack addr: %p\n", &heap_mem2); //heap_mem(0), &heap_mem(1)
//    printf("stack addr: %p\n", &heap_mem3); //heap_mem(0), &heap_mem(1)
//    
//    printf("read only string addr: %p\n", str);
//    for(int i = 0 ;i < argc; i++)
//    {
//        printf("argv[%d]: %p\n", i, argv[i]);
//    }
//    
//    for(int i = 0; env[i]; i++)
//    {
//        printf("env[%d]: %p\n", i, env[i]);
//    }
//    
//    return 0;
//}

5.3.2 运行结果

输出结果------

bash 复制代码

$ ./a.out 
code addr: 0x40055d
init global addr: 0x601034
uninit global addr: 0x601040
heap addr: 0x1791010
heap addr: 0x1791030
heap addr: 0x1791050
heap addr: 0x1791070
test static addr: 0x601038
stack addr: 0x7ffd0f9a4368
stack addr: 0x7ffd0f9a4360
stack addr: 0x7ffd0f9a4358
stack addr: 0x7ffd0f9a4350
read only string addr: 0x400800
argv[0]: 0x7ffd0f9a4811
env[0]: 0x7ffd0f9a4819
env[1]: 0x7ffd0f9a482e
env[2]: 0x7ffd0f9a4845
env[3]: 0x7ffd0f9a4850
env[4]: 0x7ffd0f9a4860
env[5]: 0x7ffd0f9a486e