hostname: do not use gethostbyname() for "hostname -s"

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@tls.msk.ru>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/networking/hostname.c b/networking/hostname.c
index d2516b5fb..b3e352242 100644
--- a/networking/hostname.c
+++ b/networking/hostname.c
@@ -106,7 +106,7 @@ 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;
@@ -134,7 +134,7 @@ 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;
@@ -159,6 +159,9 @@ int hostname_main(int argc UNUSED_PARAM, char **argv)
                                 bb_putchar('\n');
                         }
                 }
+        } else if (opts & OPT_s) {
+                strchrnul(buf, '.')[0] = '\0';
+                puts(buf);
         } else if (opts & OPT_F) {
                 /* Set the hostname */
                 do_sethostname(hostname_str, 1);