2019-08-26 20:28:45 +00:00
|
|
|
.\" Copyright (c) 2019 by Michael Kerrisk <mtk.manpages@gmail.com>
|
|
|
|
.\"
|
|
|
|
.\" %%%LICENSE_START(VERBATIM)
|
|
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
|
|
.\" preserved on all copies.
|
|
|
|
.\"
|
|
|
|
.\" Permission is granted to copy and distribute modified versions of this
|
|
|
|
.\" manual under the conditions for verbatim copying, provided that the
|
|
|
|
.\" entire resulting derived work is distributed under the terms of a
|
|
|
|
.\" permission notice identical to this one.
|
|
|
|
.\"
|
|
|
|
.\" Since the Linux kernel and libraries are constantly changing, this
|
|
|
|
.\" manual page may be incorrect or out-of-date. The author(s) assume no
|
|
|
|
.\" responsibility for errors or omissions, or for damages resulting from
|
|
|
|
.\" the use of the information contained herein. The author(s) may not
|
|
|
|
.\" have taken the same level of care in the production of this manual,
|
|
|
|
.\" which is licensed free of charge, as they might when working
|
|
|
|
.\" professionally.
|
|
|
|
.\"
|
|
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
|
|
.\" %%%LICENSE_END
|
|
|
|
.\"
|
|
|
|
.\"
|
|
|
|
.TH IPC_NAMESPACES 7 2019-08-02 "Linux" "Linux Programmer's Manual"
|
|
|
|
.SH NAME
|
2020-01-21 19:12:26 +00:00
|
|
|
ipc_namespaces \- overview of Linux IPC namespaces
|
2019-08-26 20:28:45 +00:00
|
|
|
.SH DESCRIPTION
|
|
|
|
IPC namespaces isolate certain IPC resources,
|
|
|
|
namely, System V IPC objects (see
|
|
|
|
.BR sysvipc (7))
|
|
|
|
and (since Linux 2.6.30)
|
|
|
|
.\" commit 7eafd7c74c3f2e67c27621b987b28397110d643f
|
|
|
|
.\" https://lwn.net/Articles/312232/
|
|
|
|
POSIX message queues (see
|
|
|
|
.BR mq_overview (7)).
|
|
|
|
The common characteristic of these IPC mechanisms is that IPC
|
|
|
|
objects are identified by mechanisms other than filesystem
|
|
|
|
pathnames.
|
|
|
|
.PP
|
|
|
|
Each IPC namespace has its own set of System V IPC identifiers and
|
|
|
|
its own POSIX message queue filesystem.
|
|
|
|
Objects created in an IPC namespace are visible to all other processes
|
|
|
|
that are members of that namespace,
|
|
|
|
but are not visible to processes in other IPC namespaces.
|
|
|
|
.PP
|
|
|
|
The following
|
|
|
|
.I /proc
|
|
|
|
interfaces are distinct in each IPC namespace:
|
|
|
|
.IP * 3
|
|
|
|
The POSIX message queue interfaces in
|
|
|
|
.IR /proc/sys/fs/mqueue .
|
|
|
|
.IP *
|
|
|
|
The System V IPC interfaces in
|
|
|
|
.IR /proc/sys/kernel ,
|
|
|
|
namely:
|
|
|
|
.IR msgmax ,
|
|
|
|
.IR msgmnb ,
|
|
|
|
.IR msgmni ,
|
|
|
|
.IR sem ,
|
|
|
|
.IR shmall ,
|
|
|
|
.IR shmmax ,
|
|
|
|
.IR shmmni ,
|
|
|
|
and
|
|
|
|
.IR shm_rmid_forced .
|
|
|
|
.IP *
|
|
|
|
The System V IPC interfaces in
|
|
|
|
.IR /proc/sysvipc .
|
|
|
|
.PP
|
|
|
|
When an IPC namespace is destroyed
|
|
|
|
(i.e., when the last process that is a member of the namespace terminates),
|
|
|
|
all IPC objects in the namespace are automatically destroyed.
|
|
|
|
.PP
|
|
|
|
Use of IPC namespaces requires a kernel that is configured with the
|
|
|
|
.B CONFIG_IPC_NS
|
|
|
|
option.
|
|
|
|
.SH SEE ALSO
|
|
|
|
.BR nsenter (1),
|
|
|
|
.BR unshare (1),
|
|
|
|
.BR clone (2),
|
|
|
|
.BR setns (2),
|
|
|
|
.BR unshare (2),
|
|
|
|
.BR mq_overview (7),
|
|
|
|
.BR namespaces (7),
|
|
|
|
.BR sysvipc (7)
|