FYI: new test for a hard-to-detect race fix, using gdb(!)

[Jim Meyering]

I couldn't think of any other way to test for this bug/fix.
Using gdb and counting open_safer breakpoints is ugly and a little
fragile -- and the test is skipped when there are no debugging symbols.
But it's a lot better than nothing.

Ideas for improvement welcome.

2006-12-14  Jim Meyering  <address@hidden>

        Test for a hard-to-detect race fix, using gdb.
        * tests/cp/open-perm-race: New file, to test for the
        cp --preserve=ownership fix of 2006-12-06.
        * tests/cp/Makefile.am (TESTS_ENVIRONMENT): Define abs_top_builddir.
        (TESTS): Add open-perm-race.

diff --git a/tests/cp/Makefile.am b/tests/cp/Makefile.am
index 998b59f..1fb58de 100644
--- a/tests/cp/Makefile.am
+++ b/tests/cp/Makefile.am
@@ -21,6 +21,7 @@
 AUTOMAKE_OPTIONS = 1.1 gnits

 TESTS = \
+  open-perm-race \
   backup-dir \
   src-base-dot \
   sparse \
@@ -33,7 +34,8 @@ TESTS = \
   perm cp-HL cp-i special-bits link dir-rm-dest cp-parents deref-slink \
   dir-vs-file into-self
 EXTRA_DIST = $(TESTS) trailing-slash
-TESTS_ENVIRONMENT = \
-  MAKE=$(MAKE) \
-  CONFIG_HEADER=$(CONFIG_HEADER) \
+TESTS_ENVIRONMENT =                    \
+  MAKE=$(MAKE)                         \
+  abs_top_builddir=$(abs_top_builddir) \
+  CONFIG_HEADER=$(CONFIG_HEADER)       \
   PATH="$(VG_PATH_PREFIX)`pwd`/../../src$(PATH_SEPARATOR)$$PATH"
diff --git a/tests/cp/open-perm-race b/tests/cp/open-perm-race
new file mode 100755
index 0000000..6c73438
--- /dev/null
+++ b/tests/cp/open-perm-race
@@ -0,0 +1,106 @@
+#!/bin/sh
+# Ensure that when open creates a destination file,
+# that file has properly restrictive permissions.
+# Before coreutils-6.7, there was an interval in which
+# a just-created file would have too-generous permissions.
+
+# Copyright (C) 2006 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  cp --version
+fi
+
+. $srcdir/../envvar-check
+. $srcdir/../group-names
+PRIV_CHECK_ARG=require-non-root . $srcdir/../priv-check
+
+pwd=`pwd`
+t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
+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
+
+set _ $groups; shift
+group_2=$2
+
+umask 2
+mkdir d && chgrp $group_2 d && chmod g+s,g-w d || framework_failure=1
+touch file && chmod go+w file                  || framework_failure=1
+
+( gdb --version ) > gdb.out 2>&1
+if test ! -s gdb.out; then
+  echo "$0: can't run gdb.  Skipping this test." 1>&2
+  (exit 77); exit 77
+fi
+
+( gdb -nx --batch-silent               \
+    --eval-command='break copy_reg'    \
+    --eval-command='break open_safer'  \
+    --eval-command='quit'              \
+    $abs_top_builddir/src/cp < /dev/null ) > gdb.out 2>&1
+if test -s gdb.out; then
+  cat <<EOF 1>&2
+$0: can't set breakpoints in cp.  Skipping this test.
+EOF
+  (exit 77); exit 77
+fi
+
+cat <<\EOF > gdb-cmd || framework_failure=1
+break copy_reg
+run
+break open_safer
+continue
+continue
+finish
+quit
+EOF
+
+if test $framework_failure = 1; then
+  echo "$0: failure in testing framework" 1>&2
+  (exit 1); exit 1
+fi
+
+( gdb -nx --batch-silent --command=gdb-cmd --args \
+    $abs_top_builddir/src/cp -p file d ) > gdb.out 2>&1
+# Expect no output.
+
+if test -s gdb.out; then
+  cat <<EOF 1>&2
+$0: unexpected output from gdb: (skipping this test)
+EOF
+  cat gdb.out 1>&2
+  (exit 77); exit 77
+fi
+
+fail=0
+
+# Before coreutils-6.7, the perm string would be -rw-rw----
+stat --printf='%A\n%g\n' d/file > out || fail=1
+cat <<EOF > exp || fail=1
+-rw-------
+$group_2
+EOF
+
+cmp out exp || fail=1
+test $fail = 1 && diff out exp 2> /dev/null
+
+(exit $fail); exit $fail