[PATCH] do not use gethostbyname() for hostname -s

[Michael Tokarev]

There's no reason to call gethostbyname() on the value returned
by uname() when asked just for a short name of a host.  This may
also be wrong, when uname is set to one value, but in /etc/hosts
(or elsewhere) the "canonical" name is different.  This is often
the case for localhost entry in /etc/hosts:

  127.0.0.1	localhost	myname

With this content of /etc/hosts, and uname being set to myname,
busybox hostname -s will return localhost, while regular
hostname utility returns myname.

Fix this by not calling gethostbyname() for the simple `hostname -s'
use.

Signed-off-by: Michael Tokarev <mjt at tls.msk.ru>

diff --git a/networking/hostname.c b/networking/hostname.c
index d2516b5..1e68116 100644
--- a/networking/hostname.c
+++ b/networking/hostname.c
@@ -106,12 +106,13 @@ int hostname_main(int argc UNUSED_PARAM, char **argv)
 		OPT_i = 0x4,
 		OPT_s = 0x8,
 		OPT_F = 0x10,
-		OPT_dfis = 0xf,
+		OPT_dfi = 0x7,
 	};
 
 	unsigned opts;
 	char *buf;
 	char *hostname_str;
+	char *p;
 
 #if ENABLE_LONG_OPTS
 	applet_long_options =
@@ -134,10 +135,9 @@ int hostname_main(int argc UNUSED_PARAM, char **argv)
 	if (applet_name[0] == 'd') /* dnsdomainname? */
 		opts = OPT_d;
 
-	if (opts & OPT_dfis) {
+	if (opts & OPT_dfi) {
 		/* Cases when we need full hostname (or its part) */
 		struct hostent *hp;
-		char *p;
 
 		hp = xgethostbyname(buf);
 		p = strchrnul(hp->h_name, '.');
@@ -159,6 +159,10 @@ int hostname_main(int argc UNUSED_PARAM, char **argv)
 				bb_putchar('\n');
 			}
 		}
+	} else if (opts & OPT_s) {
+		p = strchrnul(buf, '.');
+		*p = '\0';
+		puts(buf);
 	} else if (opts & OPT_F) {
 		/* Set the hostname */
 		do_sethostname(hostname_str, 1);