id: add -z, --zero option

* src/group-list.h (print_group_list): Add a parameter for the
delimiter of type char.
* src/group-list.c (print_group_list): Likewise, and use it instead
of a white space character to delimit the group entries.
* src/groups.c (main): Pass white space character to print_group_list().
* src/id.c (longopts):  Add array element for the new long option.
(usage): Document the new option.  While at it, fix the alignment
of the descriptions to match that of HELP_OPTION_DESCRIPTION.
(main): Define the bool flag opt_zero indicating the use of the
new option.  In the getopt_long loop, handle it.
Output an error diagnostic in the case the --zero option has been
specified together with the default format.
In the case of -gG, pass either a NUL or a white space character to
print_group_list() - depending on the above new flag.
Likewise change the printing of the final newline character: output
a NUL instead if the --zero option has been specified.
* doc/coreutils.texi (id invocation): Document the new option.
While at it, move the @exitstatus macro down after the macro
@primaryAndSupplementaryGroups in order to be consistent with
other texinfo documents.
(groups invocation): Move @exitstatus down after the macro
@primaryAndSupplementaryGroups here, too.
* tests/misc/id-zero.sh: Add new test exercising the new option.
* tests/local.mk (all_tests): Reference it.
* NEWS (New features): Mention the new option.
Fixes http://bugs.gnu.org/9987

2 files changed, 63 insertions, 0 deletions

diff --git a/tests/local.mk b/tests/local.mk
index b00ff5958..8f76b2371 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -277,6 +277,7 @@ all_tests =					\
   tests/misc/id-context.sh			\
   tests/misc/id-groups.sh			\
   tests/misc/id-setgid.sh			\
+  tests/misc/id-zero.sh			\
   tests/misc/md5sum.pl				\
   tests/misc/md5sum-bsd.sh			\
   tests/misc/md5sum-newline.pl			\
diff --git a/tests/misc/id-zero.sh b/tests/misc/id-zero.sh
new file mode 100755
index 000000000..cef5672fc
--- /dev/null
+++ b/tests/misc/id-zero.sh
@@ -0,0 +1,62 @@
+#!/bin/sh
+# Exercise "id --zero".
+
+# Copyright (C) 2013 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/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ id
+
+u="$( id -nu )"
+id || fail=1
+id "$u" || fail=1
+
+# id(1) should refuse --zero in default format.
+echo 'id: option --zero not permitted in default format' > err-exp \
+  || framework_failure_
+id --zero > out 2>err && fail=1
+compare /dev/null out || fail=1
+compare err-exp   err || fail=1
+
+# Create a nice list of users.
+# Add $USER to ensure we have at least one explicit entry.
+users="$u"
+# Add a few typical users to test single group and multiple groups.
+for u in root man postfix sshd nobody ; do
+  id $u >/dev/null 2>&1 && users="$users $u"
+done
+# Add $users and '' (implicit $USER) to list to process.
+printf '%s\n' $users '' >> users || framework_failure_
+
+# Exercise "id -z" with various options.
+printf '\n' > exp || framework_failure_
+:> out || framework_failure_
+
+while read u ; do
+  for o in g gr G Gr u ur ; do
+    for n in '' n ; do
+      printf   '%s: ' "id -${o}${n}[z] $u" >> exp || framework_failure_
+      printf '\n%s: ' "id -${o}${n}[z] $u" >> out || framework_failure_
+      id -${o}${n}  $u >> exp || fail=1
+      id -${o}${n}z $u  > tmp || fail=1
+      head -c-1 < tmp >> out || framework_failure_
+    done
+  done
+done < users
+printf '\n' >> out || framework_failure_
+tr '\0' ' ' < out > out2 || framework_failure_
+compare exp out2 || fail=1
+
+Exit $fail