jobs.c

一个实现基本功能的shell命令解释器

#include "myfun.h"

struct job
{
	int num[MAX/8];
	int pid_num[MAX/8];
	char status[MAX/8][50];
	char name[MAX/8][50];
};

extern pid_t pid;
extern int status;
char p_name[MAX/8];
int s_i, p_i;
struct job myjob;

void sig_child()
{
	strcpy(myjob.status[p_i], "Hold");
}

void ctrl_z()
{
	strcpy(myjob.status[s_i], "Stopped");
	printf("[%2d]\t%s\t\t%s\n", s_i, myjob.status[s_i], myjob.name[s_i]);
//	return;
}

void show_job()
{
	int i;
	printf("Num\tStatus\tID\tName\n");
	for(i=1; i<=s_i; i++)
	{
		printf("[%2d]\t%s\t%ld\t%s\n", myjob.num[i], myjob.status[i]
				   				     ,myjob.pid_num[i], myjob.name[i]);
	}
}

void jobs(char *buf_in)
{
	signal(SIGTSTP, ctrl_z);
	signal(SIGCHLD, sig_child);
	char buf[MAX/8]="";
	strcpy(buf, buf_in);
	if(strncmp(buf, "./", 2) == 0)
	{
		s_i += 1;
		strcpy(myjob.name[s_i], buf);
		myjob.num[s_i] = s_i;
		strcpy(myjob.status[s_i], "Running");
		if((pid=fork()) < 0)
		{
			printf("fork error!\n");
			exit(1);
		}
		else if(pid==0)
		{
			execlp(buf,buf,NULL);
			printf("couldn't execute: %s\n", buf);
			exit(1);
		}
		else
		{
			myjob.pid_num[s_i] = pid;
			waitpid(pid,&status,WUNTRACED);	
			strcpy(myjob.status[s_i], "Stopped");
		}
	}
	else if(strncmp(buf, "fg", 2) == 0)
	{
		if(strlen(buf) < 3)
			return;
		printf("Call to fg!\n");
		s_i = atoi(strrchr(buf, ' '));
		pid = myjob.pid_num[s_i];
		strcpy(myjob.status[s_i], "Running");
		kill(pid,SIGCONT);
		waitpid(pid,&status,WUNTRACED);
	}
	else if(strncmp(buf, "bg", 2) == 0)
	{
		if(strlen(buf) < 3)
			return;
		p_i = atoi(strrchr(buf, ' '));
		pid = myjob.pid_num[s_i];
		printf("Wake up child!\n");
		strcpy(myjob.status[s_i], "Running");
		kill(pid,SIGCONT);
	}
}