execve函数的介绍与使用

#include<stdio.h>
#include<unistd.h>
int main()
{
        char *filename[]={"./BP",NULL};//BP是c文件编译链接后产生的可执行文件，目的是打印一条语句
        char *envp[]={0,NULL};//如果依赖于新环境变量，这里才需要改
        execve("/root/BP",filename,envp);//字符串是文件的路径需要具体到该运行文件名，直到文件夹貌似识别不了，或者命令的路径
        /*注意，把下面的三个注释遇到去掉，后面的ls命令也无法执行，因为*execve执行后，相当于结束了当前的程序，切换到execve里面的那个程序*去了*/
//      char *filename1[]={"ls","-al","/root",NULL};//命令和参数，记得要加NULL
//      char *envp1[]={0,NULL};
//      execve("/bin/ls",filename1,envp1);
        return 0;
}

//BP.c
#include<stdio.h>
int main()
{
        printf("this is c process\n");
        return 0;
}

运行结果如下

没修改前的运行结果

[22:41:10] gcc execvetest.c -o execvetest

[22:41:18] gcc BP.c -o BP

[22:41:24] ./execvetest

this is c process

注释掉前三行，并且去掉后面的注释，运行结果如下

[22:45:05] gcc execvetest.c -o execvetest

[22:45:11] gcc BP.c -o BP

[22:45:23] ./execvetest

total 64

dr-xr-x—. 15 root root 4096 May 10 21:06 .

dr-xr-xr-x. 17 root root 224 Apr 30 02:52 ..

-rw——-. 1 root root 314 Apr 30 07:08 .ICEauthority

-rw——-. 1 root root 3769 May 10 18:33 .bash_history

-rw-r–r–. 1 root root 18 Dec 28 2013 .bash_logout

-rw-r–r–. 1 root root 176 Dec 28 2013 .bash_profile

-rw-r–r–. 1 root root 208 May 10 18:19 .bashrc

drwx——. 10 root root 194 Apr 30 07:09 .cache

drwx——. 15 root root 276 Apr 30 07:09 .config

-rw-r–r–. 1 root root 100 Dec 28 2013 .cshrc

drwx——. 3 root root 25 Apr 30 06:53 .dbus

-rw——-. 1 root root 16 Apr 30 07:08 .esd_auth

drwx——. 3 root root 19 Apr 30 07:08 .local

-rw-r–r–. 1 root root 129 Dec 28 2013 .tcshrc

-rwxr-xr-x. 1 root root 8512 May 10 20:55 BP

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Desktop

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Documents

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Downloads

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Music

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Pictures

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Public

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Templates

drwxr-xr-x. 2 root root 6 Apr 30 07:08 Videos

-rw——-. 1 root root 2742 Apr 30 02:52 anaconda-ks.cfg

drwxr-xr-x. 2 root root 4096 May 10 22:45 bp

-rw-r–r–. 1 root root 2750 Apr 30 06:55 initial-setup-ks.cfg

-rw——-. 1 root root 2033 Apr 30 02:52 original-ks.cfg