Template Version: @(#)sac_nextcase %I% %G% SMI
1. Introduction
    1.1. Project/Component Working Name:
	 id utility option consolidation
    1.2. Name of Document Author/Supplier:
	 Author:  Garrett D'Amore
    1.3  Date of This Document:
	01 November, 2006

1.4 Name of Major Document Customer(s)/Consumer(s)

1.4.1. The community this proposal comes from
	Garrett D'Amore

1.4.2. The ARC(s) you expect to review your project:
	PSARC

1.5. Email Aliases:

1.5.1. Responsible Manager:
	tim.sparlin@sun.com

1.5.2. Responsible Engineers:
	garrett_damore@tadpole.com
	Carol.Fields@sun.com

1.5.3. Marketing Manager:
	jeff.mcmeekin@sun.com

2.  Project Summary

Problem
-------

POSIX specifies a number of useful features for the "id" utility
which are lacking from the standard Solaris version.  The most obvious
and common case of this, is the "-u" flag, which prints the numeric
uid of the caller on standard output.

In order to work around this, many shell script writers wind up having
to write scripts involving the use of other utilities, such as sed, cut
or grep, to get the numeric user id.

This also creates portability problems for 3rd party packages, that
would like to just rely on reasonable POSIX behavior.

The specific set of arguments that id(1M) lacks in the Sun version, but
which POSIX specifies (and hence are in /usr/xpg4/bin/id) are:

	-u: print just the effective user id
	-g: print just the effective group id
	-G: print all different group ids
	-r: print the real ids instead of effective ids
	-n: print the names instead of the numeric ids

The need for these options is well documented in Sun Bug IDs 4521640
and 4514779.

Additionally, it would not be harmful if /usr/xpg4/bin/id inherited
the -a flag, from the Sun version, reducing the differences between the
Sun and POSIX versions.

The -a flag prints all supplemental groups.  This is very, very similar to
the default POSIX behavior, except that when -a is printed, the current
effective group is printed in the groups= list.

Some sample output probably serves to illustate this better.  In the following
output, user garrett is listed in /etc/passwd with primary group 10 (staff),
and is listed in the /etc/group membership for group 14 (sysadmin):

	% /usr/bin/id
	uid=1001(garrett) gid=10(staff)

	% /usr/bin/id -a
	uid=1001(garrett) gid=10(staff) groups=10(staff),14(sysadmin)

	% /usr/xpg4/bin/id
	uid=1001(garrett) gid=10(staff) groups=14(sysadmin)


As a final note, the current Solaris option parser for id is broken
in that it inconsistently allows certain illegal combinations of options.

For example, id -p -u is permitted, whereas id -u -p is not.  The behavior
of either option is not defined by either the manual page or POSIX.


Proposed Solution
-----------------

We propose to add support for the -u, -g, -G, -n, and -r options to the
standard /usr/bin/id utility, making them behave identically to the the
POSIX version in /usr/xpg4/bin/id.

Additionally, we propose to add the -a option to the version in /usr/xpg4/bin,
which will change the default behavior to match precisely the output provided
by /usr/bin/id when -a is provided.

Finally, we propose to fix the parser, so that -a and -p options are not
permitted when any of -u, -g, or -G are also specified, regardless of which
one was specified first.

The resulting /usr/bin/id and /usr/xpg4/bin/id will be 100% backwards
compatible with the documented behavior of the versions we have been shipping
for some time, and will add feature parity from POSIX to the standard
/usr/bin/id utility.

It will also remove one of the inconsistent and undocumented behaviors of
the utility by fixing an option parser bug.

As a result, the only difference remaining between the POSIX and Sun version
will the fact that when none of -u, -g, -G, or -a are specified (i.e. the
"default mode"), the POSIX version will list the additional supplemental
groups where the legacy Sun version does not.

The online manual page for id(1M) will need to be updated to reflect these
changes.


Binding
-------

We are seeking patch binding for this change.


Interface Taxonomy
------------------

The id(1M) man page did not list a stability level for /usr/bin/id and
listed /usr/xpg4/bin/id as Standard.  Both are now marked Committed.

    Interface	        		  Stability Level
 ----------------	---------------------------------------------------
 /usr/bin/id:
   all options		Committed

 /usr/xpg4/bin/id:
   -G, -g, -n, -r,	Committed: IEEE Std 1003.2-1992 and later standards
   and -u options	(see standards(5))

   -a and -p options	Committed

5.  Reference Documents

    1. updated id(1M) man page:
    	materials/id.1M

    2. related bug reports:
	4514779: *id* /usr/bin/id should at least support '-u'
	4521640: *id* /usr/bin/id missing options from /usr/xpg4/bin/id

6. Resources and Schedule
    6.4. Steering Committee requested information
   	6.4.1. Consolidation C-team Name:
		ON
    6.5. ARC review type: FastTrack