xref: /titanic_50/usr/src/man/man2/msgctl.2 (revision 0a70879558a701a07771af87e7852a12f3bfd438)
te
Copyright 1989 AT&T. Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved. Portions Copyright (c) 1992, X/Open Company Limited. All Rights Reserved.
Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.
The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.
This notice shall appear on any product containing this material.
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
MSGCTL 2 "Mar 22, 2004"
NAME
msgctl - message control operations
SYNOPSIS

#include <sys/msg.h>

int msgctl(int msqid, int cmd, struct msqid_ds *buf);
DESCRIPTION

The msgctl() function provides a variety of message control operations as specified by cmd. The following cmds are available: IPC_STAT

Place the current value of each member of the data structure associated with msqid into the structure pointed to by buf. The contents of this structure are defined in Intro(2).

IPC_SET

Set the value of the following members of the data structure associated with msqid to the corresponding value found in the structure pointed to by buf:

msg_perm.uid
msg_perm.gid
msg_perm.mode /* access permission bits only */
msg_qbytes
This command can be executed only by a process that has either the {PRIV_IPC_OWNER} privilege or an effective user ID equal to the value of msg_perm.cuid or msg_perm.uid in the data structure associated with msqid. Only a process with the {PRIV_SYS_IPC_CONFIG} privilege can raise the value of msg_qbytes.
IPC_RMID

Remove the message queue identifier specified by msqid from the system and destroy the message queue and data structure associated with it. This cmd can only be executed by a process that has an effective user ID either with appropriate privileges asserted in the effective set or equal to the value of msg_perm.cuid or msg_perm.uid in the data structure associated with msqid. The buf argument is ignored.

RETURN VALUES

Upon successful completion, msgctl() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

ERRORS

The msgctl() function will fail if: EACCES

The cmd argument is IPC_STAT and operation permission is denied to the calling process (see Intro(2)).

EFAULT

The buf argument points to an illegal address.

EINVAL

The msqid argument is not a valid message queue identifier; or the cmd argument is not a valid command or is IPC_SET and msg_perm.uid or msg_perm.gid is not valid.

EOVERFLOW

The cmd argument is IPC_STAT and uid or gid is too large to be stored in the structure pointed to by buf.

EPERM

The cmd argument is IPC_RMID or IPC_SET, the {PRIV_SYS_IPC_OWNER} privilege is not asserted in the effective set of the calling process, and is not equal to the value of msg_perm.cuid or msg_perm.uid in the data structure associated with msqid. The cmd argument is IPC_SET, an attempt is being made to increase to the value of msg_qbytes, and the {PRIV_SYS_IPC_CONFIG} privilege is not asserted in the effective set of the calling process.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Standard
SEE ALSO

Intro(2), msgget(2), msgrcv(2), msgsnd(2), attributes(5), privileges(5), standards(5)