1 #define _GNU_SOURCE
2 #include <net/if.h>
3 #include <sys/socket.h>
4 #include <sys/ioctl.h>
5 #include <string.h>
6 #include <errno.h>
7 #include "syscall.h"
8
if_indextoname(unsigned index,char * name)9 char *if_indextoname(unsigned index, char *name)
10 {
11 struct ifreq ifr;
12 int fd, r;
13
14 if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
15 ifr.ifr_ifindex = index;
16 r = ioctl(fd, SIOCGIFNAME, &ifr);
17 __syscall(SYS_close, fd);
18 if (r < 0) {
19 if (errno == ENODEV) errno = ENXIO;
20 return 0;
21 }
22 return strncpy(name, ifr.ifr_name, IF_NAMESIZE);
23 }
24