linux下C程序插入执行shell脚本

最近在看深入理解计算机系统，看到一个函数叫做execve()，这个函数很有意思，可以在一个进程插入另外一个进程执行，但是又不像fork()一样产生一个子进程，execve()插入的进程和原进程共享进程号，就好像执行这进程就像执行过程调用一般随意。

函数原型如下：

int execve(const char *filename, char *const argv[], char *const envp[]);

EXAMPLE
The following program is designed to be execed by the second program below.  It just echoes its command-line one per line.

/* myecho.c */

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

int
main(int argc, char *argv[])
{
int j;

for (j = 0; j < argc; j++)
printf("argv[%d]: %s\n", j, argv[j]);

exit(EXIT_SUCCESS);
}

This program can be used to exec the program named in its command-line argument:

/* execve.c */

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

int
main(int argc, char *argv[])
{
char *newargv[] = { NULL, "hello", "world", NULL };
char *newenviron[] = { NULL };

if (argc != 2) {
fprintf(stderr, "Usage: %s <file-to-exec>\n", argv[0]);
exit(EXIT_FAILURE);
}

newargv[0] = argv[1];

execve(argv[1], newargv, newenviron);
perror("execve");   /* execve() only returns on error */
exit(EXIT_FAILURE);
}

We can use the second program to exec the first as follows:

$ cc myecho.c -o myecho
$ cc execve.c -o execve
$ ./execve ./myecho
argv[0]: ./myecho
argv[1]: hello
argv[2]: world

插入一个shell脚本执行：

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

int
main(int argc, char *argv[])
{
char *newargv[] = { "/etc" };
char *newenviron[] = { NULL };
if (argc != 2)
{
fprintf(stderr, "Usage: %s <file-to-exec>\n", argv[0]);
exit(EXIT_FAILURE);
}

newargv[0] = argv[1];

execve(argv[1], newargv, newenviron);
perror("execve");   /* execve() only returns on error */
exit(EXIT_FAILURE);
}

script.sh如下：

#!/bin/bash
ls

执行：

./execve ./script.sh

会在当前终端下输出所有的文件

yca@ubuntu:~/桌面/hello$ ./execve ./script.sh
1          execve     hello1    hello3      hello5      hello_lex
1.txt          execve.c     hello1.c  hello3.cpp  hello5.c   k_max
Bubble          hello     hello1.o  hello3.o    hello5.o   k_max.c
Bubble.c      hello.c     hello2.c  hello3.s    hello5.s   lex.yy.c
QuickSort.c   hello.lex  hello2.o  hello4      hello5.s1  script.sh
Quicksort1.c  hello.sh     hello2.s  hello4.c    hello51.s

很好很强大~~