Attempt to copy a regular file, even if stat says it is empty.

* NEWS: Document this bug fix.
* src/copy.c (copy_reg): Read from a regular file, even if it
appears (stat.st_size == 0) to be empty.  This reverts an
optimization introduced on 2005-11-23 for coreutils-6.0.
Otherwise, "cp /proc/cpuinfo /tmp" creates an empty file,
on e.g., linux-2.6.20.
* tests/cp/proc-zero-len: New file.  Test for the above.
* tests/cp/Makefile.am (TESTS): Add proc-zero-len.
Reported by Dan Berrangé.

2 files changed, 60 insertions, 0 deletions

diff --git a/tests/cp/Makefile.am b/tests/cp/Makefile.am
index e3978c517..ecb718174 100644
--- a/tests/cp/Makefile.am
+++ b/tests/cp/Makefile.am
@@ -16,6 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 TESTS = \
+  proc-zero-len \
   thru-dangling \
   cp-a-selinux \
   file-perm-race parent-perm-race \
diff --git a/tests/cp/proc-zero-len b/tests/cp/proc-zero-len
new file mode 100755
index 000000000..cd6f94c83
--- /dev/null
+++ b/tests/cp/proc-zero-len
@@ -0,0 +1,59 @@
+#!/bin/sh
+# Ensure that cp copies contents of non-empty "regular" file with st_size==0
+
+# Copyright (C) 2007 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/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  cp --version
+fi
+
+. $srcdir/../envvar-check
+
+pwd=`pwd`
+t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
+trap 'status=$?; cd "$pwd" && chmod -R u+rwx $t0 && rm -rf $t0 && exit $status' 0
+trap '(exit $?); exit $?' 1 2 13 15
+
+framework_failure=0
+mkdir -p $tmp || framework_failure=1
+cd $tmp || framework_failure=1
+touch empty || framework_failure=1
+
+if test $framework_failure = 1; then
+  echo "$0: failure in testing framework" 1>&2
+  (exit 1); exit 1
+fi
+
+f=/proc/cpuinfo
+test -r $f || f=empty
+
+fail=0
+cat $f > out || fail=1
+
+# With coreutils-6.9, this would create a zero-length "exp" file.
+cp $f exp || fail=1
+
+# Don't simply compare contents; they might differ,
+# e.g., if CPU freq changes between cat and cp invocations.
+# Instead, simply compare whether they're both nonempty.
+test -s out && { rm -f out; echo nonempty > out; }
+test -s exp && { rm -f exp; echo nonempty > exp; }
+
+cmp out exp || fail=1
+test $fail = 1 && diff out exp 2> /dev/null
+
+(exit $fail); exit $fail