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 9char *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