From 3d53e7fe1c31aa440cc9708c7c51db6b78c07653 Mon Sep 17 00:00:00 2001
From: Pádraig Brady <P@draigBrady.com>
Date: Thu, 12 Apr 2012 12:47:30 +0100
Subject: cp: change --attributes-only to not truncate existing files

* src/copy.c (copy_reg): Don't truncate an existing file,
to support copying attributes between existing files.
The original use case only considered creating new files,
and it would be a very unusual use case to be relying
on the truncating behavior.
* doc/coreutils.texi (cp invocation): Mention the non
truncating behavior.
* tests/cp/attr-existing: A new test to ensure O_TRUNC skipped.
* tests/Makefile.am: Reference the new test.
* NEWS: Mention the change in behavior.
---
 tests/Makefile.am      |  1 +
 tests/cp/attr-existing | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100755 tests/cp/attr-existing

(limited to 'tests')

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 011051aa5..4d73a92b5 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -320,6 +320,7 @@ TESTS =						\
   chown/separator				\
   cp/abuse					\
   cp/acl					\
+  cp/attr-existing				\
   cp/backup-1					\
   cp/backup-dir					\
   cp/backup-is-src				\
diff --git a/tests/cp/attr-existing b/tests/cp/attr-existing
new file mode 100755
index 000000000..9cf0ffcb3
--- /dev/null
+++ b/tests/cp/attr-existing
@@ -0,0 +1,29 @@
+#!/bin/sh
+# Make sure cp --attributes-only doesn't truncate existing data
+
+# Copyright 2012 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program 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 General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ cp
+
+printf '1' > file1
+printf '2' > file2
+printf '2' > file2.exp
+
+cp --attributes-only file1 file2 || fail=1
+cmp file2 file2.exp || fail=1
+
+Exit $fail
-- 
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