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Networking Services Library Functionsnis_groups(3NSL)


 nis_groups, nis_ismember, nis_addmember, nis_removemember, nis_creategroup, nis_destroygroup, nis_verifygroup, nis_print_group_entry - NIS+ group manipulation functions


cc [ flag ... ] file ... -lnsl [ library ... ]
#include <rpcsvc/nis.h>
bool_t nis_ismember(nis_name principal, nis_name group);
 nis_error nis_addmember(nis_name member, nis_name group);
 nis_error nis_removemember(nis_name member, nis_name group);
 nis_error nis_creategroup(nis_name group, uint_t flags);
 nis_error nis_destroygroup(nis_name group);
 void nis_print_group_entry(nis_name group);
 nis_error nis_verifygroup(nis_name group);



These functions manipulate NIS+ groups. They are used by NIS+ clients and servers, and are the interfaces to the group authorization object.

The names of NIS+ groups are syntactically similar to names of NIS+ objects but they occupy a separate namespace. A group named "a.b.c.d." is represented by a NIS+ group object named "a.groups_dir.b.c.d."; the functions described here all expect the name of the group, not the name of the corresponding group object.

There are three types of group members:

  • An explicit member is just a NIS+ principal-name, for example "wickedwitch.west.oz."
  • An implicit ("domain") member, written "*.west.oz.", means that all principals in the given domain belong to this member. No other forms of wildcarding are allowed: "wickedwitch.*.oz." is invalid, as is "wickedwitch.west.*.". Note that principals in subdomains of the given domain are not included.
  • A recursive ("group") member, written "@cowards.oz.", refers to another group. All principals that belong to that group are considered to belong here.

Any member may be made negative by prefixing it with a minus sign ('-'). A group may thus contain explicit, implicit, recursive, negative explicit, negative implicit, and negative recursive members.

A principal is considered to belong to a group if it belongs to at least one non-negative group member of the group and belongs to no negative group members.

The nis_ismember() function returns TRUE if it can establish that principal belongs to group; otherwise it returns FALSE.

The nis_addmember() and nis_removemember() functions add or remove a member. They do not check whether the member is valid. The user must have read and modify rights for the group in question.

The nis_creategroup() and nis_destroygroup() functions create and destroy group objects. The user must have create or destroy rights, respectively, for the groups_dir directory in the appropriate domain. The parameter flags to nis_creategroup() is currently unused and should be set to zero.

The nis_print_group_entry() function lists a group's members on the standard output.

The nis_verifygroup() function returns NIS_SUCCESS if the given group exists, otherwise it returns an error code.

These functions only accept fully-qualified NIS+ names.

A group is represented by a NIS+ object with a variant part that is defined in the group_obj structure. See nis_objects(3NSL). It contains the following fields:

uint_t	gr_flags;	/* Interpretation Flags
			(currently unused) */
struct {
	uint_t	gr_members_len;
	nis_name	*gr_members_val;
} gr_members;		/* Array of members */

NIS+ servers and clients maintain a local cache of expanded groups to enhance their performance when checking for group membership. Should the membership of a group change, servers and clients with that group cached will not see the change until either the group cache has expired or it is explicitly flushed. A server's cache may be flushed programmatically by calling the nis_servstate() function with tag TAG_GCACHE and a value of 1.

There are currently no known methods for nis_ismember(), nis_print_group_entry(), and nis_verifygroup() to get their answers from only the master server.


 Example 1. Simple Memberships

Given a group sadsouls.oz. with members tinman.oz., lion.oz., and scarecrow.oz., the function call

bool_var = nis_ismember("lion.oz.", "sadsouls.oz.");

will return 1 (TRUE) and the function call

bool_var = nis_ismember("toto.oz.", "sadsouls.oz.");

will return 0 (FALSE).

Example 2. Implicit Memberships

Given a group baddies.oz., with members wickedwitch.west.oz. and *.monkeys.west.oz., the function call bool_var = nis_ismember("hogan.monkeys.west.oz.", "baddies.oz."); will return 1 (TRUE) because any principal from the monkeys.west.oz. domain belongs to the implicit group *.monkeys.west.oz., but the function call
bool_var = nis_ismember("hogan.big.monkeys.west.oz.", "baddies.oz.");
will return 0 (FALSE).

Example 3. Recursive Memberships

Given a group goodandbad.oz., with members toto.kansas, @sadsouls.oz., and @baddies.oz., and the groups sadsouls.oz. and baddies.oz. defined above, the function call

bool_var = nis_ismember("wickedwitch.west.oz.", "goodandbad.oz.");

will return 1 (TRUE), because wickedwitch.west.oz. is a member of the baddies.oz. group which is recursively included in the goodandbad.oz. group.



See attributes(5) for descriptions of the following attributes:




nisgrpadm(1), nis_objects(3NSL), attributes(5)



NIS+ might not be supported in future releases of the Solaris Operating Environment. Tools to aid the migration from NIS+ to LDAP are available in the Solaris 9 operating environment. For more information, visit

SunOS 5.9Go To TopLast Changed 18 Dec 2001

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.