test.c

Linux 2.6版本下的简单的字符设备模块示例

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <error.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>

#include "hello.h"

int main(int argc, char **argp)
{
    int fd = open("/dev/my_driver", O_RDWR, 0664);
    if(fd < 0)
    {
        perror("open \"/dev/my_driver\" failure");
        return EXIT_FAILURE;
    }
    
    printf("fd:%d\n",fd);
    int iSize = ioctl(fd, HELLO_IOGBUFFERSIZE);
    if(iSize == -1)
    {
        perror("ioctl:HELLO_IOGBUFFERSIZE");
    }
    else
    {
        printf("get buffer size:%d\n", iSize);
    }
    int iSize2 = ioctl(fd, HELLO_IOGBUFFERSIZE2, &iSize);
    if(iSize2 == -1)
    {
        perror("ioctl:HELLO_IOGBUFFERSIZE2");
    }
    else
    {
        printf("get buffer size:%d\n", iSize);
    }
    int iSize3 = ioctl(fd, 12345);
    if(iSize3 == -1)
    {
        perror("ioctl:12345");
    }
    else
    {
        printf("get buffer size:%d\n", iSize);
    }


    char *pWriteData = "abcdefghijklmnopqrstuvwxyz123456789";
    char szBuffer[1024] = {0};
    int iReadBytes = 0;
    int iWriteBytes = write(fd, pWriteData, strlen(pWriteData));
    if(iWriteBytes == strlen(pWriteData))
    {
        printf("write data \"%s\" to \"/dev/my_driver\" success.\n");
        iReadBytes = read(fd, szBuffer, strlen(pWriteData));
        if(iReadBytes > 0)
        {
            printf("read data from \"/dev/my_driver\" success,data:%s.\n",szBuffer);
        }
        else
        {
            printf("read data from \"/dev/my_driver\" failure.\n");
        }
    }
    else
    {
        printf("write data to \"/dev/my_driver\" failure, %d.\n",iWriteBytes);
    }
    
    close(fd);
    fd = -1;
    return EXIT_SUCCESS;
}