20155332 mybash的实现

mybash 的实现

码云链接

https://gitee.com/bestiisjava2017/laura5332/blob/master/信息安全系统设计/mybash.c

遇到的问题

• 定义 char *arlgist[[3];

解决方案

• 动态分配内存空间后，运行就没有问题了。

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

#include <string.h>

#define DELAY 2

void child_code(int delay,char *arglist[3])

{

	//printf("child %d here will sleep for %d seconds\n",getpid(),delay);

	//sleep(delay);

	execvp("who",arglist);

	//printf("child done. about to exit\n");

	exit(17);

}

void parent_code (int childpid)

{

	int wait_rv=0;

	wait_rv = wait(NULL);

	//printf("done waiting %d .wait returned :%d\n",childpid,wait_rv);

}

int main()

{

	fork();

	char *arglist[3];

	arglist[0]=(char*)malloc(sizeof(char)*10);

	arglist[1]=(char*)malloc(sizeof(char)*10);

	scanf("%s",arglist[0]);

	scanf("%s",arglist[1]);

	//arglist[0]="who";

	//arglist[1]="-a";

	arglist[2]=0;

	//printf("%s",arglist[2]);

	int newpid;

	//printf("before:mypid is %d \n",getpid());

	if((newpid = fork())==-1)

		perror("fork");

	else if(newpid==0)

		child_code(DELAY,arglist);

	else parent_code(newpid);

	return 0;

}