c读取linux mac地址

ip link show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 00:16:3e:00:00:01 brd ff:ff:ff:ff:ff:ff

ifconfig

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.100  netmask 255.255.255.0  broadcast 192.168.1.255
        ether 00:16:3e:00:00:01  txqueuelen 1000  (Ethernet)
        RX packets 12345  bytes 1234567 (1.2 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 23456  bytes 2345678 (2.3 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

cat /sys/class/net/eth0/address

#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <unistd.h>
#include <arpa/inet.h>

int main() {
    int sockfd;
    struct ifreq ifr;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("socket");
        return 1;
    }

    strncpy(ifr.ifr_name, "eth0", IFNAMSIZ - 1);
    ifr.ifr_name[IFNAMSIZ - 1] = '\0';

    if (ioctl(sockfd, SIOCGIFHWADDR, &ifr) < 0) {
        perror("ioctl");
        close(sockfd);
        return 1;
    }

    unsigned char *mac = (unsigned char *)ifr.ifr_hwaddr.sa_data;
    printf("MAC Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
           mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);

    close(sockfd);
    return 0;
}