Version of id(1).

[Mr N W Holloway]

I saw a request somewhere for a program like the SysV id(1). I got used
to it under SunOS, and so I wrote this one to use on our BSD machines.
As far as I can tell, they act identically - though I can't check this,
since I do not have access to source. The only area they may differ is
if the user or group name can not be determined.

There is no man page - the program is very simple, it justs prints out
info on your real & effective user & group id, and your current group
access list.  Example (mythical) outputs are:

   uid=0(root) gid=0(wheel) groups=0(wheel),1(daemon) 
   uid=1074(alfie) gid=1(general) euid=1(daemon) groups=1(general)

To compile, no magic flags needed, just "cc -o id id.c".

--
Nick Holloway |  `O O'  | alfie at cs.warwick.ac.uk, alfie at warwick.UUCP,
[aka `Alfie'] | // ^ \\ | ..!uunet!mcsun!ukc!warwick!alfie

#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
#	id.c
# This archive created: Thu Mar  1 13:15:51 1990
export PATH; PATH=/bin:$PATH
if test -f 'id.c'
then
	echo shar: will not over-write existing file "'id.c'"
else
cat << \SHAR_EOF > 'id.c'
/* My own version of `id' for those systems that do not support it
 * Displays uid, gid, euid, egid (if different to real), and groups
 *
 * Author:	Nick Holloway <alfie at cs.warwick.ac.uk>
 * Date:	August 17th 1989
 * Place:	University of Warwick, Coventry, UK
 */
# include <stdio.h>
# include <sys/param.h>
# include <pwd.h>
# include <grp.h>

main ()
{
    int  uid, euid;		/* real and effective user-id  */
    int  gid, egid;		/* real and effective group-id */
    int  gidset [ NGROUPS ];	/* current group access list   */
    int  ng, i;			/* number of groups, index var */
    struct passwd *pwd;		/* used to retrieve user name  */
    struct group  *grp;		/* used to retrieve group name */

    /* --- collect information --- */
    uid = getuid ();
    gid = getgid ();
    euid = geteuid ();
    egid = getegid ();
    ng = getgroups ( sizeof ( gidset ), gidset );

    /* --- print real user-id --- */
    (void) printf ( "uid=%d", uid );
    if ( ( pwd = getpwuid ( uid ) ) != NULL )
	(void) printf ( "(%s)", pwd->pw_name );

    /* --- print real group-id --- */
    (void) printf ( " gid=%d", gid );
    if ( ( grp = getgrgid ( gid ) ) != NULL )
	(void) printf ( "(%s)", grp->gr_name );

    /* --- print effective user-id (if different to real) --- */
    if ( euid != uid ) {
	(void) printf ( " euid=%d", euid );
	if ( ( pwd = getpwuid ( euid ) ) != NULL )
	    (void) printf ( "(%s)", pwd->pw_name );
    }

    /* --- print effective group-id (if different to real) --- */
    if ( egid != gid ) {
	(void) printf ( " egid=%d", egid );
	if ( ( grp = getgrgid ( egid ) ) != NULL )
	    (void) printf ( "(%s)", grp->gr_name );
    }

    /* --- print current group access list --- */
    if ( ng > 0 ) {
	(void) fputs ( " groups=", stdout );
	for ( i = 0; i < ng; i++ ) {
	    if ( i != 0 )
		(void) putc ( ',', stdout );
	    (void) printf ( "%d", gidset [ i ] );
	    if ( ( grp = getgrgid ( gidset [ i ] ) ) != NULL )
		(void) printf ( "(%s)", grp->gr_name );
	}
    }

    (void) putc ( '\n', stdout );
}
SHAR_EOF
fi # end of overwriting check
#	End of shell archive
exit 0