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host-info.c
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host-info.c
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/*
* File Name: host-info.c
* Description: Shows host information - the IP address and Hostname
* Author: Suyash Singh Bitti
*
* Note:
* gethostbyname() is DEPRECATED and doesn't work well with IPv6, you should be
* using getaddrinfo()
*/
#include <stdio.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#define HOST_NAME_BUFF_LEN 255
int main(int argc, char *argv[])
{
char hostNameBuff[HOST_NAME_BUFF_LEN];
struct hostent *ci; /* Client Info */
struct in_addr **addr_list;
int i;
if(argc == 2){
/* hostname passed as command line arg */
if((ci = gethostbyname(argv[1])) == NULL) {
herror("gethostbyname");
return 2;
}
} else {
if(gethostname(hostNameBuff, sizeof hostNameBuff) == -1) {
perror("gethostname");
return 1;
}
if((ci = gethostbyname(hostNameBuff)) == NULL) {
herror("gethostbyname");
return 2;
}
}
printf("Hostname: %s\n", ci->h_name);
addr_list = (struct in_addr **)ci->h_addr_list;
printf("IP Address: ");
for(i = 0; addr_list[i] != NULL; i++) {
printf("%s ", inet_ntoa(*addr_list[i]));
}
printf("\n");
return 0;
}