dread.c

请在解压时看说明文档 内有详细说明

/************************************************************/
/*****dread.c, this is a test program for upperdrv.c *****/
/************************************************************/

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <asm/io.h>
#include "softdev.h"

/************************************************************/
/***** define some constants used in upperdrv.c  *****/
/************************************************************/
#ifndef _UPPER_DEVICE_H
#define _UPPER_DEVICE_H
#include <linux/ioctl.h>
#define UPPER_MAJOR 117
#define UPPER_LOW2UPPER 1 // change the input string from low to upper characters
#define UPPER_UNCHAN 0     //copy the input string to the output
#define UPPER_MAGIC UPPER_MAJOR
#define UPPER_RESET _IO(UPPER_MAGIC,0)   // reset the data
#define UPPER_QUERY_NEW_MSG _IO(UPPER_MAGIC,1) // check for new message
#define UPPER_QUERY_MSG_LENGTH _IO(UPPER_MAGIC,2) // get message length
#define IOC_NEW_MSG 1
#endif

char buf[1512];

int main(int argc,char **argv) {
	int i;
	int fd,len,quit=0;
	if(argc!=2) {
		printf("syntax: dread + upper \n");
		exit(0);
	}
	fd=open("/dev/upper",O_RDONLY);
	if(fd<0) {
		printf("Error opening device for reading!\n");
		return 0;
	}
	while(!quit) {
		printf("\n read>>");
	while(!ioctl(fd,UPPER_QUERY_NEW_MSG))
		usleep(1000);
// get the msg length
	len=ioctl(fd,UPPER_QUERY_MSG_LENGTH,NULL);
	if(len) {
			printf("msg_len=%d\n",len);
			for(i=0;i<1512;i++) buf[i]=0;
			len=read(fd,buf,len);
			if(len<0) {
				printf("Error reading from device!");
			}
			else if(!strcmp(buf,"exit")) {
					ioctl(fd,UPPER_RESET);     // reset
				}
			else 
					printf("%s\n",buf);
//			quit=1;
		//if the line "quit=1"  is removed, the program exit after receive one mesg
			}
	}
	close(fd);
	return 0;
}