ldconfig: Do not remove stale symbolic links with -X [BZ #19610]

ChangeLog

@@ -1,3 +1,14 @@
+2016-03-07  Florian Weimer  <fweimer@redhat.com>
+
+	[BZ #19610]
+	* elf/ldconfig.c (opt_link): Update comment.
+	(options): Update help string for option -X.
+	(search_dir): Unlink stale symbolic link only if updating symbolic
+	links.
+	* elf/tst-ldconfig-X.sh: New file.
+	* elf/Makefile (tests-special): Add tst-ldconfig-X.out.
+	(tst-ldconfig-X.out): New rule to run tst-ldconfig-X.sh.
+
 2016-03-07  Andreas Schwab  <schwab@suse.de>
 
 	* iconv/gconv_builtin.h ("=ascii->INTERNAL"): Correct min/max

elf/Makefile

@@ -163,7 +163,8 @@ endif
 endif
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)tst-leaks1-mem.out \
-		 $(objpfx)tst-leaks1-static-mem.out $(objpfx)noload-mem.out
+		 $(objpfx)tst-leaks1-static-mem.out $(objpfx)noload-mem.out \
+		 $(objpfx)tst-ldconfig-X.out
 endif
 tlsmod17a-suffixes = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
 tlsmod18a-suffixes = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
@@ -1252,3 +1253,7 @@ $(objpfx)tst-prelink-cmp.out: tst-prelink.exp \
 			      $(objpfx)tst-prelink-conflict.out
 	cmp $^ > $@; \
 	$(evaluate-test)
+
+$(objpfx)tst-ldconfig-X.out : tst-ldconfig-X.sh $(objpfx)ldconfig
+	$(SHELL) $< '$(common-objpfx)' '$(test-wrapper)' '$(test-wrapper-env)' > $@; \
+	$(evaluate-test)

elf/ldconfig.c

@@ -100,7 +100,8 @@ int opt_format = 1;
 /* Build cache.  */
 static int opt_build_cache = 1;
 
-/* Generate links.  */
+/* Enable symbolic link processing.  If set, create or update symbolic
+   links, and remove stale symbolic links.  */
 static int opt_link = 1;
 
 /* Only process directories specified on the command line.  */
@@ -141,7 +142,7 @@ static const struct argp_option options[] =
   { "print-cache", 'p', NULL, 0, N_("Print cache"), 0},
   { "verbose", 'v', NULL, 0, N_("Generate verbose messages"), 0},
   { NULL, 'N', NULL, 0, N_("Don't build cache"), 0},
-  { NULL, 'X', NULL, 0, N_("Don't generate links"), 0},
+  { NULL, 'X', NULL, 0, N_("Don't update symbolic links"), 0},
   { NULL, 'r', N_("ROOT"), 0, N_("Change to and use ROOT as root directory"), 0},
   { NULL, 'C', N_("CACHE"), 0, N_("Use CACHE as cache file"), 0},
   { NULL, 'f', N_("CONF"), 0, N_("Use CONF as configuration file"), 0},
@@ -800,7 +801,7 @@ search_dir (const struct dir_entry *entry)
 		error (0, errno, _("Cannot stat %s"), file_name);
 
 	      /* Remove stale symlinks.  */
-	      if (strstr (direntry->d_name, ".so."))
+	      if (opt_link && strstr (direntry->d_name, ".so."))
 		unlink (real_file_name);
 	      continue;
 	    }

elf/tst-ldconfig-X.sh

@@ -0,0 +1,62 @@
+#!/bin/sh
+# Test that ldconfig -X does not remove stale symbolic links.
+# Copyright (C) 2000-2016 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
+# <http://www.gnu.org/licenses/>.
+
+set -ex
+
+common_objpfx=$1
+test_wrapper_env=$2
+run_program_env=$3
+
+testroot="${common_objpfx}elf/bug19610-test-directory"
+cleanup () {
+    rm -rf "$testroot"
+}
+trap cleanup 0
+
+rm -rf "$testroot"
+mkdir -p $testroot/lib $testroot/etc
+
+# Relative symbolic link target.
+ln -s libdoesnotexist.so.1.1 $testroot/lib/libdoesnotexist.so.1
+
+# Absolute symbolic link target.
+ln -s $testroot/opt/sw/lib/libdoesnotexist2.so.1.1 $testroot/lib/
+
+errors=0
+check_files () {
+    for name in libdoesnotexist.so.1 libdoesnotexist2.so.1.1 ; do
+	path="$testroot/lib/$name"
+	if test ! -h $path ; then
+	    echo "error: missing file: $path"
+	    errors=1
+	fi
+    done
+}
+
+check_files
+
+${test_wrapper_env} \
+${run_program_env} \
+${common_objpfx}elf/ldconfig -X -f /dev/null \
+  -C $testroot/etc/ld.so.cache \
+  $testroot/lib
+
+check_files
+
+exit $errors