Linux C语言检查进程是否存在

/*
*  COPYRIGHT NOTICE
*  Copyright (C) 2016 HuaHuan Electronics Corporation, Inc. All rights reserved
*
*  Author       	:Kevin_fzs
*  File Name        	:/home/kevin/works/projects/MIPS53003/drivers/webRestart.c
*  Create Date        	:2016/08/04 01:11
*  Last Modified      	:2016/08/04 01:11
*  Description    	:
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int getRestartStatus()
{
char *name="/home/webserver/Rflag.txt";
FILE *fd;
int ret=0;

fd = fopen(name, "r");
if(NULL == fd)
return 1;
else
return 0;
}

int main()
{
FILE *ptr = NULL;
char cmd[128] = "ps -ef | grep appweb | grep -v grep | wc -l";
int status = 0;
char buf[150];
int count;

while(1)
{
status = getRestartStatus();<span style="white-space:pre">				</span>//根据标志文件来决定是否要检查进程
if(status)
{
if((ptr = popen(cmd, "r"))==NULL)
{
printf("popen err\n");
continue;
}

memset(buf, 0, sizeof(buf));

if((fgets(buf, sizeof(buf),ptr))!= NULL)<span style="white-space:pre">		</span>//获取进程和子进程的总数
{
count = atoi(buf);
if(count <= 0)<span style="white-space:pre">			</span>//当进程数小于等于0时，说明进程不存在
{
system("/home/appweb_start.sh");
printf("restart appweb \n");
}

}

}
usleep(200000);
}
}