resolv: Move dn_comp to its own file and into libc

And reformat it to GNU style.

dn_comp is used in various programs, so keep it as a non-deprecated
symbol.  Switch to dn_comp (not __dn_comp) for the ABI name.  There
are no internal users, so interposition is not a problem.

The __dn_comp symbol was moved with scripts/move-symbol-to-libc.py
--no-new-version.  dn_comp@@GLIBC_2.34 was added with
make update-all-abi.

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

5 files changed, 106 insertions, 17 deletions

diff --git a/resolv/Makefile b/resolv/Makefile
index 07cac54..9365185 100644
--- a/resolv/Makefile
+++ b/resolv/Makefile
@@ -28,6 +28,7 @@ headers	:= resolv.h bits/types/res_state.h \
 	   sys/bitypes.h
 
 routines := \
+  dn_comp \
   dn_expand \
   herror \
   inet_addr \
diff --git a/resolv/Versions b/resolv/Versions
index 4a92030..e36cf45 100644
--- a/resolv/Versions
+++ b/resolv/Versions
@@ -1,5 +1,6 @@
 libc {
   GLIBC_2.0 {
+    __dn_comp;
     __h_errno_location;
     __res_randomid;
     _res;
@@ -42,6 +43,7 @@ libc {
     gai_suspend;
     getaddrinfo_a;
 %endif
+    dn_comp;
     dn_expand;
     ns_name_compress;
     ns_name_ntop;
@@ -79,7 +81,6 @@ libresolv {
   GLIBC_2.0 {
     __b64_ntop;
     __b64_pton;
-    __dn_comp;
     __dn_count_labels;
     __dn_skipname;
     __fp_nquery;
diff --git a/resolv/dn_comp.c b/resolv/dn_comp.c
new file mode 100644
index 0000000..4506a62
--- /dev/null
+++ b/resolv/dn_comp.c
@@ -0,0 +1,103 @@
+/* Compressing a DNS domain name from presentation form to wire format.
+   Copyright (C) 1995-2021 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/>.  */
+
+/*
+ * Copyright (c) 1985, 1993
+ *    The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Portions Copyright (c) 1993 by Digital Equipment Corporation.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies, and that
+ * the name of Digital Equipment Corporation not be used in advertising or
+ * publicity pertaining to distribution of the document or software without
+ * specific, written prior permission.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
+ * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+/*
+ * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+/* Packs domain name SRC in presentation form into DST.  Returns the
+   size of the compressed name or -1.  DSTSIZ is the size of the array
+   pointed to by COMPDN.  */
+int
+___dn_comp (const char *src, unsigned char *dst, int dstsiz,
+            unsigned char **dnptrs, unsigned char **lastdnptr)
+{
+  return __ns_name_compress (src, dst, (size_t) dstsiz,
+                             (const unsigned char **) dnptrs,
+                             (const unsigned char **) lastdnptr);
+}
+versioned_symbol (libc, ___dn_comp, dn_comp, GLIBC_2_34);
+
+#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libresolv, ___dn_comp, __dn_comp, GLIBC_2_0);
+#endif
diff --git a/resolv/res_comp.c b/resolv/res_comp.c
index 80faea7..1930f17 100644
--- a/resolv/res_comp.c
+++ b/resolv/res_comp.c
@@ -93,21 +93,6 @@
 #include <unistd.h>
 
 /*
- * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
- * Return the size of the compressed name or -1.
- * 'length' is the size of the array pointed to by 'comp_dn'.
- */
-int
-dn_comp(const char *src, u_char *dst, int dstsiz,
-	u_char **dnptrs, u_char **lastdnptr)
-{
-	return (ns_name_compress(src, dst, (size_t)dstsiz,
-				 (const u_char **)dnptrs,
-				 (const u_char **)lastdnptr));
-}
-libresolv_hidden_def (dn_comp)
-
-/*
  * Skip over a compressed domain name. Return the size or -1.
  */
 int
diff --git a/resolv/resolv.h b/resolv/resolv.h
index 7232d81..0e91801 100644
--- a/resolv/resolv.h
+++ b/resolv/resolv.h
@@ -210,7 +210,6 @@ __END_DECLS
 
 #define b64_ntop		__b64_ntop
 #define b64_pton		__b64_pton
-#define dn_comp			__dn_comp
 #define dn_count_labels		__dn_count_labels
 #define dn_skipname		__dn_skipname
 #define fp_resstat		__fp_resstat