src/first_network_device.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

// vim:ts=8:expandtab
#include <sys/stat.h>
#include <stdlib.h>
#include <ifaddrs.h>

#include "i3status.h"

const char *first_eth_interface(const net_type_t type) {
        static char *interface = NULL;
        struct ifaddrs *ifaddr, *addrp;
        struct stat stbuf;
        static char path[1024];

        getifaddrs(&ifaddr);

        if (ifaddr == NULL)
                return NULL;

        free(interface);
        interface = NULL;
        for (addrp = ifaddr;
             addrp != NULL;
             addrp = addrp->ifa_next) {
                if (strncasecmp("lo", addrp->ifa_name, strlen("lo")) == 0)
                        continue;
                // Skip this interface if it is a wireless interface.
                snprintf(path, sizeof(path), "/sys/class/net/%s/wireless", addrp->ifa_name);
                const bool is_wireless = (stat(path, &stbuf) == 0);
                if (( is_wireless && type == NET_TYPE_ETHERNET) ||
                    (!is_wireless && type == NET_TYPE_WIRELESS))
                        continue;
                interface = strdup(addrp->ifa_name);
                break;
        }

        freeifaddrs(ifaddr);
        return interface;
}