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)