NAME
initgroups —
initialize group access list
LIBRARY
Standard system libraries.
SYNOPSIS
#include
<unistd.h>
int
initgroups(const
char *name, int
basegid);
DESCRIPTION
The
initgroups()
function calculates a group access list for the user specified in
name. This group list is then saved in the kernel
credentials for the current process. The basegid is
included in the groups list. Typically this value is given as the default
group associated with the user's account record.
This function sets at most 16 group IDs in the process
credentials. This list can be retrieved using the
getgroups(2) function. Note that OS X supports group membership in an
unlimited number of groups. The OS X kernel uses the group list stored in
the process credentials only as an initial cache. Additional group
memberships are determined by communication between the operating system and
the opendirectoryd daemon.
Processes should not use the group ID numbers from
getgroups(2) to determine a user's group membership. The list
obtained from
getgroups()
may only be a partial list of a user's group membership. Membership checks
should use the
mbr_gid_to_uuid(3),
mbr_uid_to_uuid(3), and
mbr_check_membership(3) functions.
RETURN VALUES
The initgroups() function returns 0 on
success. On failure, this function will return -1 and set
errno to one of the following values:
- [
EPERM] - The caller's effictive UID is not zero.
- [
EINVAL] - Internal error, an invalid array size was supplied to the kernel.
- [
EFAULT] - Internal error, invalid data was supplied to the kernel.
SEE ALSO
getgroups(2), getgrouplist(3), mbr_gid_to_uuid(3), mbr_uid_to_uuid(3), mbr_check_membership(3).
HISTORY
The initgroups() function appeared in
4.2BSD.