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>

1 files changed, 51 insertions, 0 deletions

diff --git a/resolv/res_hostalias.c b/resolv/res_hostalias.c
new file mode 100644
index 0000000000..d364725677
--- /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));
+}