GETGROUPS(2) System Calls GETGROUPS(2)
NAME
getgroups, setgroups - get or set supplementary group access list IDs
SYNOPSIS
#include <unistd.h>
int getgroups(
int gidsetsize,
gid_t *grouplist);
int setgroups(
int ngroups,
const gid_t *grouplist);
DESCRIPTION
The
getgroups() function gets the current supplemental group access list
of the calling process and stores the result in the array of group IDs
specified by
grouplist. This array has
gidsetsize entries and must be
large enough to contain the entire list. This list cannot be larger than
NGROUPS_UMAX. If
gidsetsize equals 0,
getgroups() will return the number
of groups to which the calling process belongs without modifying the
array pointed to by
grouplist.
The
setgroups() function sets the supplementary group access list of the
calling process from the array of group IDs specified by
grouplist. The
number of entries is specified by
ngroups and can not be greater than
NGROUPS_MAX.
RETURN VALUES
Upon successful completion,
getgroups() returns the number of
supplementary group IDs set for the calling process and
setgroups() returns
0. Otherwise,
-1 is returned and
errno is set to indicate the
error.
ERRORS
The
getgroups() and
setgroups() functions will fail if:
EFAULT A referenced part of the array pointed to by
grouplist is an
illegal address.
The
getgroups() function will fail if:
EINVAL The value of
gidsetsize is non-zero and less than the number of
supplementary group IDs set for the calling process.
The
setgroups() function will fail if:
EINVAL The value of
ngroups is greater than {
NGROUPS_MAX}.
EPERM The {
PRIV_PROC_SETID} privilege is not asserted in the
effective set of the calling process.
USAGE
Use of the
setgroups() function requires the {
PRIV_PROC_SETID} privilege.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+--------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+--------------------------+
|Interface Stability |
getgroups() is Standard. |
+--------------------+--------------------------+
|MT-Level | Async-Signal-Safe |
+--------------------+--------------------------+
SEE ALSO
groups(1),
chown(2),
getuid(2),
setuid(2),
getgrnam(3C),
initgroups(3C),
attributes(7),
privileges(7),
standards(7) September 8, 2006
GETGROUPS(2)