mbr_check_membership.3   [plain text]

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.Dd February 3, 2005
.Dt MBR_CHECK_MEMBERSHIP 3
.Os "Mac OS X"
.Sh NAME
.Nm mbr_check_membership
.Nd check whether a user is a member of a group
.Sh SYNOPSIS
.In membership.h
.Ft int
.Fn mbr_check_membership "uuid_t user" "uuid_t group" "int *ismember"
.Sh DESCRIPTION
.Fn mbr_check_membership
tests if a given user is a member of a group, individually or as a member of a nested group.
.Fa ismember
is set to 1 if the user is a member of the group, and 0 otherwise.  
.Pp
Users may belong to any number of groups.
.Fn mbr_check_membership
should be always be used to check group membership, rather than
calling
.Xr getgroups 2 ,
and checking the returned list of gids.
The
.Xr setgroups 2
and
.Xr getgroups 2
routines are limited to a fixed number of gids,
and so may not include all of a user's groups.
.Pp
There are two special cases.
If the two uuids are equal, then 
.Fa ismember
is set to 1.
If the
.Fa group
uuid is equal to the reserved "everyone" uuid (ABCDEFAB-CDEF-ABCD-EFAB-CDEF0000000C), then
.Fa ismember
will be set to 1 for any valid user.
.Pp
Group membership information is managed by the
.Xr DirectoryService 8
daemon.
.Sh RETURN VALUES
.Fn mbr_check_membership
returns 0 on success.
It returns EIO if it is unable to communicate with the
.Xr DirectoryService 8
daemon.
ENOENT is returned if
.Fa user
cannot be found.
.Pp
Note that 
.Fn mbr_check_membership
does not test whether
.Fa group
exists or not.
Querying membership for a nonexistent group will result in
.Fa ismember
being to 0 and a return value of 0.
.Sh SEE ALSO
.Xr setgroups 2 ,
.Xr getgroups 2 ,
.Xr mbr_uid_to_uuid 3 ,
.Xr DirectoryService 8