linux+c+获取网关地址

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

void get_gateway(char *gateway_ip) {
    FILE *fp;
    char line[1024], *p, *c;
    int found = 0;

    fp = popen("ip route show default", "r");
    if (!fp) {
        perror("popen");
        return;
    }

    while (fgets(line, sizeof(line), fp)) {
        if (strstr(line, "default via")) {
            p = strtok(line, " ");
            while (p) {
                if (strstr(p, "via ")) {
                    c = strtok(p, " ");
                    strcpy(gateway_ip, c);
                    found = 1;
                    break;
                }
                p = strtok(NULL, " ");
            }
            break;
        }
    }

    pclose(fp);

    if (!found) {
        strcpy(gateway_ip, "Not Found");
    }
}

int main() {
    char gateway_ip[16];
    get_gateway(gateway_ip);
    printf("Default Gateway: %s\n", gateway_ip);
    return 0;
}