MBR_CHECK_MEMBERSHIP(3)

NAME
mbr_check_membership, mbr_check_service_membership - check whether a user is a member of a group or service ACL

SYNOPSIS
#include <membership.h>
int
mbr_check_membership(uuid_t user, uuid_t group, int *ismember);
int
mbr_check_service_membership(uuid_t user, const char *service, int *ismember);

DESCRIPTION
mbr_check_membership() tests if a given user is a member of a group (either direct or indirect via a nested group). ismember is set to 1 if the user is a member or 0 if not a member of the group. mbr_check_service_membership() similarly tests if a given user is a member of a service ACL group. Service ACLs are special groups defined with the prefix "com.apple.access_". The service is then prefixed (e.g., "afp" would check "com.apple.access_afp"). There is a special group that grants accessto all services called "com.apple.access_all_services".

Users may belong to any number of groups. mbr_check_membership() should always be used to check group membership, rather than calling getgroups(2) or getgrouplist(2). The setgroups(2) and getgroups(2) routines are limited to a fixed number of gids, and so may not include all of a user's groups.

There are two special cases. If the two uuids are equal, then ismember is set to 1. If the group uuid is equal to the reserved "everyone" uuid (ABCDEFAB-CDEF-ABCD-EFAB-CDEF0000000C), then ismember will be set to 1 for any valid user.

Group membership information is managed by opendirectoryd(8).

RETURN VALUES
mbr_check_membership() does not test whether group exists or not. Querying membership for a nonexistent group will result in ismember being set to 0. The function returns 0 on success or one of the following error codes on failure:

[EIO]
    Communication with openditectoryd(8) failed.

[ENOENT]
    user can not be found.

mbr_check_service_membership() is identical to mbr_check_membership() except that ENOENT means no service ACL has been defined.

SEE ALSO
odutil(1), setgroups(2), getgroups(2), mbr_uid_to_uuid(3), opendirectoryd(8)