linux系统ioctl函数使用实例

由于源代码注释几乎没有，可能新手较难看懂。因此鄙人加上了注释，有些小错误的地方也改了一下，其它不多说了。

程序1：检测接口的 inet_addr,netmask,broad_addr

程序2：检查接口的物理连接是否正常

程序3：更简单一点测试物理连接

程序4：调节音量

 

程序1：检测接口的 inet_addr,netmask,broad_addr

 

可能用到的资料：

1.ioctl和struct ifreq  

    http://wenku.baidu.com/view/59f4508d680203d8ce2f2412.html

    上面链接中的源代码，头文件需要自己修改一下

 

//程序1：检测接口的 inet_addr,netmask,broad_addr
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <sys/ioctl.h>
#include <net/if.h>

static void usage(){
        printf("usage : ipconfig interface\n");
        exit(0);
}

int main(int argc,char **argv)
{
        struct sockaddr_in *addr;       //套接字地址结构体
        struct ifreq ifr;               //用于ioctl
        char *name, *address;           //网络设备的名字，地址
        int sockfd;                     //套接子描述符

        if(argc != 2) //参数不够
                usage();
        else
                name = argv[1];


        sockfd = socket(AF_INET, SOCK_DGRAM, 0); //打开一个数据流套接子
        strncpy(ifr.ifr_name, name, IFNAMSIZ-1); //限制设备名的长度并截断，防止溢出


        if(ioctl(sockfd, SIOCGIFADDR, &ifr)  == -1)     //用 SIOCGIFADDR 来获得接口地址
                perror("ioctl error"), exit(1);         //描述错误代码
        addr = (struct sockaddr_in *)&(ifr.ifr_addr);
        address = inet_ntoa(addr->sin_addr);            //地址转换
        printf("inet addr: %s ",address);


        if(ioctl(sockfd, SIOCGIFBRDADDR, &ifr)  ==  -1) //用 SIOCGIFBRDADDR 来获得广播地址
                perror("ioctl error"),exit(1);
        addr = (struct sockaddr_in *)&ifr.ifr_broadaddr;
        address = inet_ntoa(addr->sin_addr);
        printf("broad addr: %s ",address);


        if(ioctl(sockfd, SIOCGIFNETMASK, &ifr) == -1) //用 SIOCGIFNETMASK 来获得掩码地址
                perror("ioctl error"),exit(1);
        addr = (struct sockaddr_in *)&ifr.ifr_addr;
        address = inet_ntoa(addr->sin_addr);
        printf("inet mask: %s ",address);

        printf("\n");
        exit(0);
}

 

程序2：检查接口的物理连接是否正常

//程序2：检查接口的物理连接是否正常
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <stdlib.h>
#include <unistd.h>

typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned char u8;

#include <linux/ethtool.h>
#include <linux/sockios.h>


int detect_mii(int skfd, char *ifname)
{
        struct ifreq ifr;
        u16 *data, mii_val;
        unsigned phy_id;

        //Get the vitals from the interface.
        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);

        //MII=(媒介无关接口）
        //PHY=物理链路
        if (ioctl(skfd, SIOCGMIIPHY, &ifr) < 0)
        {
                fprintf(stderr, "SIOCGMIIPHY on %s failed: %s\n", ifname,
                strerror(errno));
                (void) close(skfd);
                return 2;
        }

        data = (u16 *)(&ifr.ifr_data);
        phy_id = data[0];
        data[1] = 1;

        //REG regedit
        if (ioctl(skfd, SIOCGMIIREG, &ifr) < 0)
        {
                fprintf(stderr, "SIOCGMIIREG on %s failed: %s\n", ifr.ifr_name,
                strerror(errno));
                return 2;
        }

        mii_val = data[3];

        return(((mii_val & 0x0016) == 0x0004) ? 0 : 1);
}


int detect_ethtool(int skfd, char *ifname)
{
        struct ifreq ifr;
        struct ethtool_value edata;

        memset(&ifr, 0, sizeof(ifr));
        edata.cmd = ETHTOOL_GLINK;

        strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
        ifr.ifr_data = (char *) &edata;

        //ETH : EtherNet n. 以太网O
        /\tOOL 工具
        if (ioctl(skfd, SIOCETHTOOL, &ifr) == -1)
        {
                printf("ETHTOOL_GLINK failed: %s\n", strerror(errno));
                return 2;
        }

        return (edata.data ? 0 : 1);
}

int main(int argc, char **argv)
{
        int skfd = -1;          //套接子描述符
        char *ifname;         //接口设备名
        int retval;             //返回值

        if( argv[1] )
                ifname = argv[1];
        else
                ifname = "eth0";        //默认值

        //打开一个套接子
        if (( skfd = socket( AF_INET, SOCK_DGRAM, 0 ) ) < 0 )
        {
                printf("socket error\n");
                exit(-1);
        }

        //探测以太网设备
        retval = detect_ethtool(skfd, ifname);

        if (retval == 2)//上面失败情况下
                //探测物理链路
                retval = detect_mii(skfd, ifname);


        close(skfd);

        if (retval == 2)
                printf("Could not determine status\n");

        if (retval == 1)
                printf("Link down\n");

        if (retval == 0)
                printf("Link up\n");

        return retval;
}

 

程序3：更简单一点测试物理连接 

//程序3：更简单一点测试物理连接
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <net/if.h>
#include <linux/sockios.h>
#include <sys/ioctl.h>
#define LINKTEST_GLINK 0x0000000a

struct linktest_value {
        unsigned int    cmd;
        unsigned int    data;
};

static
void
usage(const char * pname)
{
        fprintf(stderr, "usage: %s <device>\n", pname);
        fprintf(stderr, "returns: \n");
        fprintf(stderr, "\t 0: link detected\n");
        fprintf(stderr, "\t%d: %s\n", ENODEV, strerror(ENODEV));
        fprintf(stderr, "\t%d: %s\n", ENONET, strerror(ENONET));
        fprintf(stderr, "\t%d: %s\n", EOPNOTSUPP, strerror(EOPNOTSUPP));
        exit(EXIT_FAILURE);
}

static
int
linktest(const char * devname)
{
        struct ifreq ifr;
        struct linktest_value edata;
        int fd;

        // setup our control structures.
        memset(&ifr, 0, sizeof(ifr));
        strcpy(ifr.ifr_name, devname);//为什么没有用strncpy了

        //open control socket.
        fd = socket(AF_INET, SOCK_DGRAM, 0);
        if(fd < 0 ) {
                return -ECOMM;
        }

        errno = 0;
        edata.cmd = LINKTEST_GLINK;
        ifr.ifr_data = (caddr_t)&edata;

        if(!ioctl(fd, SIOCETHTOOL, &ifr)) {
                if(edata.data) {
                        fprintf(stdout, "link detected on %s\n", devname);
                        return 0;
                } else {
                        errno=ENONET;
                }
        }

        perror("linktest");
        return errno;
}

int
main(int argc, char *argv[])
{
        if(argc != 2) {
                usage(argv[0]);
        }
        return linktest(argv[1]);
}

 

 

程序4：调节音量 

可能用到的资料：

Linux的混音设备/dev/mixer  

http://blog.163.com/ji_wei8888/blog/static/48680446201110925825588/

//程序4：调节音量
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>
#include <stdio.h>
#include <unistd.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

#define  BASE_VALUE 257

int main(int argc,char *argv[])
{
        int mixer_fd=0;
        char *names[SOUND_MIXER_NRDEVICES]=SOUND_DEVICE_LABELS;
        int value,i;

        //检查参数
        if (argc<3)
        {
                printf("\nusage:%s dev_no.[0..24] value[0..100]\n\n",argv[0]);
                printf("eg. %s 0 100\n",argv[0]);
                printf("    will change the volume to MAX volume.\n\n");
                printf("The dev_no. are as below:\n");
                for (i=0; i<SOUND_MIXER_NRDEVICES; i++){
                        if (i%3==0)
                                printf("\n");
                        printf("%s:%d\t\t",names[i], i);
                }
                printf("\n\n");
                exit(1);
        }

        //打开文件
        if ((mixer_fd = open("/dev/mixer",O_RDWR))){
                printf("Mixer opened successfully,working...\n");
                value = BASE_VALUE*atoi(argv[2]);

                //修改文件
                if (ioctl(mixer_fd,  MIXER_WRITE(atoi(argv[1])), &value)==0)
                        printf("successfully.....");
                else
                        printf("unsuccessfully.....");
                printf("done.\n");
         }else
                printf("can't open /dev/mixer error....\n");
        exit(0);
}