1 #include <netinet/ether.h>
2 #include <stdio.h>
3 #include <sys/mman.h>
4 #include <sys/types.h>
5 #include <sys/stat.h>
6 #include <fcntl.h>
7 #include <stdlib.h>
8 
9 /* glibc 2.4 has no ETHER_FILE_NAME, host compile fails without this */
10 #ifndef ETHER_FILE_NAME
11 #define ETHER_FILE_NAME "/etc/ethers"
12 #endif
13 
14 #define ETHER_LINE_LEN 256
15 
16 /* This test requires /etc/ethers to exist
17  * and to have nonzero length
18  */
19 
main(void)20 int main(void)
21 {
22 	struct ether_addr addr;
23 	char hostname[ETHER_LINE_LEN];
24 	int fd, i;
25 	const char *ethers;
26 	struct stat statb;
27 
28 	if ((fd = open(ETHER_FILE_NAME, O_RDONLY)) == -1) {
29 		perror ("Cannot open file");
30 		exit(1);
31 	}
32 
33 	if (fstat(fd, &statb)) {
34 		perror("Stat failed");
35 		exit(1);
36 	}
37 	ethers = mmap(NULL, statb.st_size, PROT_READ, MAP_SHARED, fd, 0);
38 
39 	if (ethers == MAP_FAILED) {
40 		perror("File mapping failed");
41 		exit(1);
42 	}
43 
44 	ether_line(ethers, &addr, hostname);
45 
46 	for (i = 0; i < 6; i++) {
47 		printf("%02x", addr.ether_addr_octet[i]);
48 		if (i < 5)
49 			printf(":");
50 	}
51 	printf(" %s\n", hostname);
52 
53 	return 0;
54 }
55