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)
