Re: hostname(1) change

[Kent Ibbetson <bsd@xxxxxxxxxx>]

Hey Matt n all,

Matthew Dillon probed the keyboard and on Mon, Jan 05, 2004 at 08:29:58AM -0800 produced:
> 
> :> now do the following and get the same result;
> :>
> :> hostname www.6bone.net
> :> hostname -r 3ffe:b00:c18:1::10
> :> hostname -r 206.123.31.124
> :
> :Yes, that looks great. Patch looks good too. Can a committer look at it?
> :
> :Cheers,
> :Emiel
> 
>     Oh yes, it will go in regardless, it is fine work!   I'm just waiting
>     on the -i interface support.
> 
> 					-Matt
> 					Matthew Dillon 
> 					<dillon@xxxxxxxxxxxxx>

Thanks Matt, here's the latest patch, it adds -i functionality, so now you can;

hostname -i tun0 -4 |
hostname -i tun0    |- to get the hostname of the first resolving IPv4 address on tun0

hostname -i tun0 -6    to get the hostname of the first resolving IPv6 address on tun0

It seems to work well, no odd behaviour, let me know if there's any problems
with it.  There's probably a few minor touch-ups, but from testing here its
functionally stable (is that an oxymoron? :) )


Cheers,

-- 
Kent Ibbetson
bsd@xxxxxxxxxx

*** bin/hostname/hostname.1.orig	Tue Jun 17 14:22:50 2003
--- bin/hostname/hostname.1	Tue Jan  6 12:55:39 2004
***************
*** 42,48 ****
  .Sh SYNOPSIS
  .Nm
  .Op Fl s
! .Op Ar name-of-host
  .Sh DESCRIPTION
  The
  .Nm
--- 42,48 ----
  .Sh SYNOPSIS
  .Nm
  .Op Fl s
! .Op Ar name-of-host | -r ip-address | -i interface [-6 | -4]
  .Sh DESCRIPTION
  The
  .Nm
***************
*** 62,67 ****
--- 62,78 ----
  .It Fl s
  Trim off any domain information from the printed
  name.
+ .It Fl r
+ Retrieve hostname via ip lookup.  The hostname is set to the first (official)
+ name returned for the supplied ip address.  Can be an IPv6 or IPv4 address.
+ .It Fl i
+ Retrieve hostname via supplied interface name.
+ .It Fl 6
+ Used in conjunction with -i to select the 1st IPv6 address on the interface.
+ .It Fl 4
+ Used in conjunction with -i to select the 1st IPv4 address on the interface.
+ This is the default and assumed if -6 or -4 is not supplied.
+ 
  .El
  .Sh SEE ALSO
  .Xr gethostname 3 ,
*** bin/hostname/hostname.c.orig	Mon Sep 29 00:39:14 2003
--- bin/hostname/hostname.c	Tue Jan  6 12:55:38 2004
***************
*** 37,42 ****
--- 37,58 ----
   */
  
  #include <sys/param.h>
+ #include <sys/ioctl.h>
+ #include <sys/socket.h>
+ #include <sys/sysctl.h>
+ #include <sys/time.h>
+ #include <sys/module.h>
+ #include <sys/linker.h>
+ 
+ 
+ #include <net/ethernet.h>
+ #include <net/if.h>
+ #include <net/if_var.h>
+ #include <net/if_dl.h>
+ #include <net/if_types.h>
+ #include <net/route.h>
+ #include <netinet/in.h>
+ 
  
  #include <err.h>
  #include <stdio.h>
***************
*** 44,61 ****
  #include <string.h>
  #include <unistd.h>
  
  int main (int, char *[]);
  void usage (void);
  
  int
  main(int argc, char **argv)
  {
! 	int ch, sflag;
! 	char *p, hostname[MAXHOSTNAMELEN];
  
! 	sflag = 0;
! 	while ((ch = getopt(argc, argv, "s")) != -1)
  		switch (ch) {
  		case 's':
  			sflag = 1;
  			break;
--- 60,162 ----
  #include <string.h>
  #include <unistd.h>
  
+ #include <netdb.h>
+ #include <sys/types.h>
+ #include <netinet/in.h>
+ #include <arpa/inet.h>
+ 
+ #include <errno.h>
+ 
+ #define HST_IF    (1 << 0)
+ #define HST_IF_V6 (1 << 1)
+ #define HST_IF_V4 (1 << 2)
+ 
+ 
+ 
+ /*
+  * Expand the compacted form of addresses as returned via the
+  * configuration read via sysctl().
+  * Lifted from getifaddrs(3)
+  */
+ 
+ void	rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
+ 
+ #define ROUNDUP(a) \
+ 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+ #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
+ 
+ void
+ rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
+ {
+ 	struct sockaddr *sa;
+ 	int i;
+ 
+ 	memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
+ 	for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
+ 		if ((rtinfo->rti_addrs & (1 << i)) == 0)
+ 			continue;
+ 		rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
+ 		ADVANCE(cp, sa);
+ 	}
+ }
+ 
+ 
  int main (int, char *[]);
  void usage (void);
  
  int
  main(int argc, char **argv)
  {
! 	int ch,sflag,rflag,ret,flag6,iflag;
! 	char hostname[MAXHOSTNAMELEN];
! 	char *srflag,*siflag;
! 	struct hostent *hst;
! 	struct in_addr ia;
! 	struct in6_addr ia6;
  
! 	int mib[6];
! 	int needed;
! 	char *buf,*lim,*next,*p;
! 	int idx;
! 	struct sockaddr_dl *sdl;
! 	struct rt_msghdr *rtm;
! 	struct if_msghdr *ifm;
! 	struct ifa_msghdr *ifam;
! 	struct rt_addrinfo info;
! 	struct sockaddr_in *sai;
! 	struct sockaddr_in6 *sai6;
! 
! 	srflag = NULL;
! 	iflag = sflag = rflag = 0;
! 	flag6 = 0;
! 	hst = NULL;
! 
! 	while ((ch = getopt(argc, argv, "46i:r:s")) != -1)
  		switch (ch) {
+ 		case '4':
+ 			iflag |= HST_IF_V4;
+ 			break;
+ 		case '6':
+ 			iflag |= HST_IF_V6;
+ 			break;
+ 		case 'i':
+ 			siflag = (char*)calloc(1,sizeof(char) * (strlen((char*)optarg)+1));
+ 			if(siflag) {
+ 				iflag |= HST_IF;
+ 				strlcpy(siflag, (char*)optarg, strlen((char*)optarg)+1);
+ 			} else {
+ 				errx(1, "malloc");
+ 			}
+ 			break;
+ 		case 'r':
+ 			srflag = (char*)calloc(1,sizeof(char) * (strlen((char*)optarg)+1));
+ 			if(srflag) {
+ 				rflag = 1;
+ 				strlcpy(srflag, (char*)optarg, strlen((char*)optarg)+1);
+ 			} else {
+ 				errx(1, "malloc");
+ 			}
+ 			break;
  		case 's':
  			sflag = 1;
  			break;
***************
*** 69,75 ****
  	if (argc > 1)
  		usage();
  
! 	if (*argv) {
  		if (sethostname(*argv, (int)strlen(*argv)))
  			err(1, "sethostname");
  	} else {
--- 170,329 ----
  	if (argc > 1)
  		usage();
  
! 	if (iflag && *argv) {
! 		free(siflag);
! 		usage();
! 	}
! 
! 	if (rflag && *argv) {
! 		free(srflag);
! 		usage();
! 	}
! 
! 	if(rflag && (iflag & HST_IF)) {
! 		usage();
! 		free(srflag);
! 		free(siflag);
! 	}
! 
! 	if((iflag & HST_IF_V6) && (iflag & HST_IF_V4)) {
! 		free(siflag);
! 		usage();
! 	}
! 
! 	if( !(iflag & HST_IF) && ((iflag & HST_IF_V6)||iflag & HST_IF_V4) ){
! 		free(siflag);
! 		usage();
! 	}
! 
! 	if(iflag & HST_IF) {
! 		mib[0] = CTL_NET;
! 		mib[1] = PF_ROUTE;
! 		mib[2] = 0;
! 		mib[3] = 0;
! 		mib[4] = NET_RT_IFLIST;
! 		mib[5] = 0;
! 
! 		idx = 0;
! 		needed = 1;
! 
! 		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
! 			free(siflag);
! 			errx(1, "iflist-sysctl-estimate:%i",errno);
! 		}
! 		if ((buf = malloc(needed)) == NULL) {
! 			free(siflag);
! 			errx(1, "malloc");
! 		}
! 		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
! 			free(siflag);
! 			errx(1, "actual retrieval of interface table");
! 		}
! 	
! 		lim = buf + needed;
! 
! 		for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
! 			rtm = (struct rt_msghdr *)(void *)next;
! 			if (rtm->rtm_version != RTM_VERSION)
! 				continue;
! 			switch (rtm->rtm_type) {
! 			case RTM_IFINFO:
! 				ifm = (struct if_msghdr *)(void *)rtm;
! 
! 				if (ifm->ifm_addrs & RTA_IFP) {
! 					sdl = (struct sockaddr_dl *)(ifm+1);
! 
! 					if(strcmp(siflag,sdl->sdl_data) == 0) {
! 						idx = ifm->ifm_index;
! 					}
! 				}
! 
! 			break;
! 			case RTM_NEWADDR:
! 				ifam = (struct ifa_msghdr *)(void *)rtm;
! 
! 				if(ifam->ifam_index == idx) {
! 
! 					info.rti_addrs = ifam->ifam_addrs;
! 					rt_xaddrs((char *)(ifam + 1),
! 						ifam->ifam_msglen + (char *)ifam, &info);
! 					sai = (struct sockaddr_in *)info.rti_info[RTAX_IFA];
! 
! 					if(iflag & HST_IF_V6) {
! 						if (sai->sin_family == AF_INET6) {
! 							sai6 = (struct sockaddr_in6 *)info.rti_info[RTAX_IFA];
! 							hst = gethostbyaddr((const char*)&sai6->sin6_addr,
! 									sizeof(sai6->sin6_addr),AF_INET6);
! 
! 							if(h_errno == NETDB_SUCCESS) {
! 								next = buf + needed;
! 								continue;
! 							}
! 						}
! 					} else {
! 						if((sai->sin_family == AF_INET)) {
! 
! 							hst = gethostbyaddr((const char*)&sai->sin_addr,
! 									sizeof(sai->sin_addr),AF_INET);
! 
! 							if(h_errno == NETDB_SUCCESS) {
! 								next = buf + needed;
! 								continue;
! 							}
! 						}
! 					}
! 				}
! 			break;
! 			}
! 		}
! 
! 
! 		free(buf);
! 		free(siflag);
! 
! 		if(idx == 0) {
! 			errx(1,"interface not found");
! 		}
! 
! 		if(h_errno == NETDB_SUCCESS) {
! 			if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
! 				errx(1, "sethostname");
! 		} else if(h_errno == HOST_NOT_FOUND) {
! 			errx(1,"hostname not found");
! 		} else {
! 			errx(1,"gethostbyaddr");
! 		}
! 
! 		if(idx == 0) {
! 			errx(1,"interface not found");
! 		}
! 	} else if(rflag) {
! 		ret = inet_pton(AF_INET, srflag, &ia);
! 		if(ret != 1) {
! 			// check IPV6
! 			ret = inet_pton(AF_INET6, srflag, &ia6);
! 
! 			if(ret != 1) {
! 				free(srflag);
! 				errx(1, "invalid ip address");
! 			}
! 
! 			flag6 = 1;
! 		}
! 		
! 		if(flag6 == 1) 
! 			hst = gethostbyaddr((const char*)&ia6, sizeof(ia6), AF_INET6);
! 		else
! 			hst = gethostbyaddr((const char*)&ia, sizeof(ia), AF_INET);
! 		if(!hst) {
! 			free(srflag);
! 			if(h_errno == HOST_NOT_FOUND) 
! 				errx(1,"host not found\n");
! 		}
! 
! 		if (sethostname(hst->h_name, (int)strlen(hst->h_name)))
! 			err(1, "sethostname");
! 	} else if (*argv) {
  		if (sethostname(*argv, (int)strlen(*argv)))
  			err(1, "sethostname");
  	} else {
***************
*** 86,91 ****
  usage(void)
  {
  
! 	(void)fprintf(stderr, "usage: hostname [-s] [name-of-host]\n");
  	exit(1);
  }
--- 340,345 ----
  usage(void)
  {
  
! 	(void)fprintf(stderr, "usage: hostname [-s] [name-of-host | -r ip-address | -i interface [-4 | -6]]\n");
  	exit(1);
  }