resolv: Move res_hostalias into its own file, along with hostalias

These deprecated symbols continue to be exported from libresolv.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

3 files changed, 52 insertions, 30 deletions

diff --git a/resolv/Makefile b/resolv/Makefile
index bfcca70..8c28afe 100644
--- a/resolv/Makefile
+++ b/resolv/Makefile
@@ -152,6 +152,7 @@ libresolv-routines := \
   res_data \
   res_debug \
   res_enable_icmp \
+  res_hostalias \
   res_isourserver \
   res_mkquery \
   res_query \
diff --git a/resolv/res_hostalias.c b/resolv/res_hostalias.c
new file mode 100644
index 0000000..d364725
--- /dev/null
+++ b/resolv/res_hostalias.c
@@ -0,0 +1,51 @@
+/* HOSTALIASES-based name resolution.  Public legacy functions.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <netdb.h>
+#include <resolv-internal.h>
+#include <resolv_context.h>
+
+/* Common part of res_hostalias and hostalias.  */
+static const char *
+context_hostalias_common (struct resolv_context *ctx,
+                          const char *name, char *dst, size_t siz)
+{
+  if (ctx == NULL)
+    {
+      RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);
+      return NULL;
+    }
+  const char *result = __res_context_hostalias (ctx, name, dst, siz);
+  __resolv_context_put (ctx);
+  return result;
+}
+
+const char *
+res_hostalias (res_state statp, const char *name, char *dst, size_t siz)
+{
+  return context_hostalias_common
+    (__resolv_context_get_override (statp), name, dst, siz);
+}
+
+const char *
+hostalias (const char *name)
+{
+  static char abuf[MAXDNAME];
+  return context_hostalias_common
+    (__resolv_context_get (), name, abuf, sizeof (abuf));
+}
diff --git a/resolv/res_query.c b/resolv/res_query.c
index 45c591a..2457193 100644
--- a/resolv/res_query.c
+++ b/resolv/res_query.c
@@ -635,36 +635,6 @@ res_querydomain (const char *name, const char *domain, int class, int type,
     (__resolv_context_get (), name, domain, class, type, answer, anslen);
 }
 
-/* Common part of res_hostalias and hostalias.  */
-static const char *
-context_hostalias_common (struct resolv_context *ctx,
-			  const char *name, char *dst, size_t siz)
-{
-  if (ctx == NULL)
-    {
-      RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);
-      return NULL;
-    }
-  const char *result = __res_context_hostalias (ctx, name, dst, siz);
-  __resolv_context_put (ctx);
-  return result;
-}
-
-const char *
-res_hostalias (res_state statp, const char *name, char *dst, size_t siz)
-{
-  return context_hostalias_common
-    (__resolv_context_get_override (statp), name, dst, siz);
-}
-
-const char *
-hostalias (const char *name)
-{
-  static char abuf[MAXDNAME];
-  return context_hostalias_common
-    (__resolv_context_get (), name, abuf, sizeof (abuf));
-}
-
 #if SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
 # undef res_query
 # undef res_querydomain