Remove hard-coded default for RHS

Don't fall back to using a default RHS when the configuration file can't
be read and there isn't a suitable value set in the environment.
Original report from https://bugzilla.redhat.com/show_bug.cgi?id=1332493

Author: nalind

src/lib/Makefile.am

@@ -15,7 +15,7 @@ noinst_PROGRAMS = hestest
 hestest_SOURCES = hestest.c
 hestest_LDADD = libhesiod.la
 
-TESTS_ENVIRONMENT = ./hestest
+TESTS_ENVIRONMENT = HES_DOMAIN=athena.mit.edu ./hestest
 TESTS = hestest.conf
 
 EXTRA_DIST = hesiod.conf.sample hestest.conf

src/lib/hesiod.c

@@ -82,7 +82,6 @@ static const char rcsid[] = "$Id: hesiod.c,v 1.30 2002-04-03 21:40:55 ghudson Ex
 #endif
 
 /* Defaults if the configuration file is not present. */
-#define DEF_RHS ".athena.mit.edu"
 #define DEF_LHS ".ns"
 
 /* Maximum size of a Hesiod response from the DNS. */
@@ -141,6 +140,12 @@ int hesiod_init(void **context)
 	      else
 		errno = ENOMEM;
 	    }
+	  /* Make sure that the rhs is set. */
+	  if (!ctx->rhs)
+	    {
+	      errno = EINVAL;
+	      return -1;
+	    }
 	  else
 	    return 0;
 	}
@@ -302,13 +307,12 @@ static int read_config_file(struct hesiod_p *ctx, const char *filename)
   fp = fopen(filename, "r");
   if (!fp)
     {
-      /* Use compiled in default domain names. */
+      /* Use compiled in default LHS. */
       ctx->lhs = malloc(strlen(DEF_LHS) + 1);
-      ctx->rhs = malloc(strlen(DEF_RHS) + 1);
-      if (ctx->lhs && ctx->rhs)
+      ctx->rhs = NULL;
+      if (ctx->lhs)
 	{
 	  strcpy(ctx->lhs, DEF_LHS);
-	  strcpy(ctx->rhs, DEF_RHS);
 	  return 0;
 	}
       else