From 08983ab5cb0b8de9df3759fffe621c1cdcff6c0d Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Tue, 8 Oct 2019 15:34:15 -0500
Subject: Add dnsdomainname, fix "hostname -d" segfault on machine with no
 domain name, and cleanup hostname to only call gethostname() once.

It passes the one test in test_hostname, if that helps.
---
 toys/lsb/hostname.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/toys/lsb/hostname.c b/toys/lsb/hostname.c
index ac7f9163..b3cc1967 100644
--- a/toys/lsb/hostname.c
+++ b/toys/lsb/hostname.c
@@ -5,6 +5,7 @@
  * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/hostname.html
 
 USE_HOSTNAME(NEWTOY(hostname, ">1bdsfF:[!bdsf]", TOYFLAG_BIN))
+USE_DNSDOMAINNAME(NEWTOY(dnsdomainname, ">0", TOYFLAG_BIN))
 
 config HOSTNAME
   bool "hostname"
@@ -19,9 +20,18 @@ config HOSTNAME
     -f	Show fully-qualified name (host+domain, FQDN)
     -F	Set hostname to contents of FILENAME
     -s	Show short host name (no domain)
+
+config DNSDOMAINNAME
+  bool "dnsdomainname"
+  default y
+  help
+    usage: dnsdomainname
+
+    Show domain this system belongs to (same as hostname -d).
 */
 
 #define FOR_hostname
+#define FORCE_FLAGS
 #include "toys.h"
 
 GLOBALS(
@@ -30,21 +40,17 @@ GLOBALS(
 
 void hostname_main(void)
 {
-  char *hostname = *toys.optargs, *dot;
+  char *hostname = toybuf, *dot;
   struct hostent *h;
 
+  gethostname(toybuf, sizeof(toybuf)-1);
   if (TT.F && (hostname = xreadfile(TT.F, 0, 0))) {
     if (!*chomp(hostname)) {
       if (CFG_TOYBOX_FREE) free(hostname);
       if (!FLAG(b)) error_exit("empty '%s'", TT.F);
       hostname = 0;
     }
-  }
-
-  // Implement -b.
-  if (!hostname && FLAG(b))
-    if (gethostname(toybuf, sizeof(toybuf)-1) || !*toybuf)
-      hostname = "localhost";
+  } else hostname  = (FLAG(b) && !*toybuf) ? "localhost" : *toys.optargs;
 
   // Setting?
   if (hostname) {
@@ -53,14 +59,18 @@ void hostname_main(void)
     return;
   }
 
-  // Get the hostname.
-  if (gethostname(toybuf, sizeof(toybuf)-1)) perror_exit("gethostname");
   // We only do the DNS lookup for -d and -f.
   if (FLAG(d) || FLAG(f)) {
     if (!(h = gethostbyname(toybuf))) perror_exit("gethostbyname");
     snprintf(toybuf, sizeof(toybuf), "%s", h->h_name);
   }
-  dot = strchr(toybuf, '.');
-  if (FLAG(s) && dot) *dot = '\0';
+  dot = toybuf+strcspn(toybuf, ".");
+  if (FLAG(s)) *dot = '\0';
   xputs(FLAG(d) ? dot+1 : toybuf);
 }
+
+void dnsdomainname_main(void)
+{
+  toys.optflags = FLAG_d;
+  hostname_main();
+}
-- 
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