env, printenv: add -0/--null option

Allows for unambiguous processing when environment values (or even
non-portable names!) contain newline.

* src/env.c (longopts): Add new option.
(usage): Document it.
(main): Implement it.
* src/printenv.c (longopts): New variable.
(usage): Document new option.
(main): Implement it.
* doc/coreutils.texi (Common options): New macro optNull.
(du invocation, env invocation, printenv invocation): Use it.
* NEWS: Mention this.
* tests/misc/env-null: New test.
* tests/Makefile.am (TESTS): Run it.

1 files changed, 69 insertions, 0 deletions

diff --git a/tests/misc/env-null b/tests/misc/env-null
new file mode 100755
index 000000000..432c6594e
--- /dev/null
+++ b/tests/misc/env-null
@@ -0,0 +1,69 @@
+#!/bin/sh
+# Verify behavior of env -0 and printenv -0.
+
+# Copyright (C) 2009 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
+  env --version
+  env -- printenv --version
+fi
+
+. $srcdir/test-lib.sh
+
+fail=0
+
+# POSIX is clear that environ may, but need not be, sorted.
+# Environment variable values may contain newlines, which cannot be
+# observed by merely inspecting output from env.
+# Cygwin requires a minimal environment to launch new processes: execve
+# adds missing variables SYSTEMROOT and WINDIR, which show up in a
+# subsequent env.  Cygwin also requires /bin to always be part of PATH,
+# and attempts to unset or reduce PATH may cause execve to fail.
+#
+# For these reasons, it is better to compare two outputs from distinct
+# programs that should be the same, rather than building an exp file.
+env -i PATH="$PATH" env -0 > out1 || fail=1
+env -i PATH="$PATH" printenv -0 > out2 || fail=1
+compare out1 out2 || fail=1
+env -i PATH="$PATH" env --null > out2 || fail=1
+compare out1 out2 || fail=1
+env -i PATH="$PATH" printenv --null > out2 || fail=1
+compare out1 out2 || fail=1
+
+# env -0 does not work if a command is specified.
+env -0 echo hi > out
+test $? = 125 || fail=1
+test -s out && fail=1
+
+# Test env -0 on a one-variable environment.
+printf 'a=b\nc=\0' > exp || framework_failure
+env -i -0 "$(printf 'a=b\nc=')" > out || fail=1
+compare exp out || fail=1
+
+# Test printenv -0 on particular values.
+printf 'b\nc=\0' > exp || framework_failure
+env "$(printf 'a=b\nc=')" printenv -0 a > out || fail=1
+compare exp out || fail=1
+env -u a printenv -0 a > out
+test $? = 1 || fail=1
+test -s out && fail=1
+env -u b "$(printf 'a=b\nc=')" printenv -0 b a > out
+test $? = 1 || fail=1
+compare exp out || fail=1
+
+Exit $fail