NAME¶
setns - reassociate thread with a namespace
SYNOPSIS¶
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <sched.h>
int setns(int fd, int nstype);
DESCRIPTION¶
Given a file descriptor referring to a namespace, reassociate the calling thread
with that namespace.
The
fd argument is a file descriptor referring to one of the namespace
entries in a
/proc/[pid]/ns/ directory; see
proc(5) for further
information on
/proc/[pid]/ns/. The calling thread will be reassociated
with the corresponding namespace, subject to any constraints imposed by the
nstype argument.
The
nstype argument specifies which type of namespace the calling thread
may be reassociated with. This argument can have one of the following values:
- 0
- Allow any type of namespace to be joined.
- CLONE_NEWIPC
- fd must refer to an IPC namespace.
- CLONE_NEWNET
- fd must refer to a network namespace.
- CLONE_NEWUTS
- fd must refer to a UTS namespace.
Specifying
nstype as 0 suffices if the caller knows (or does not care)
what type of namespace is referred to by
fd. Specifying a nonzero value
for
nstype is useful if the caller does not know what type of namespace
is referred to by
fd and wants to ensure that the namespace is of a
particular type. (The caller might not know the type of the namespace referred
to by
fd if the file descriptor was opened by another process and, for
example, passed to the caller via a UNIX domain socket.)
RETURN VALUE¶
On success,
setns() returns 0. On failure, -1 is returned and
errno is set to indicate the error.
ERRORS¶
- EBADF
- fd is not a valid file descriptor.
- EINVAL
- fd refers to a namespace whose type does not match
that specified in nstype, or there is problem with reassociating
the the thread with the specified namespace.
- ENOMEM
- Cannot allocate sufficient memory to change the specified
namespace.
- EPERM
- The calling thread did not have the required privilege
(CAP_SYS_ADMIN) for this operation.
VERSIONS¶
The
setns() system call first appeared in Linux in kernel 3.0; library
support was added to glibc in version 2.14.
The
setns() system call is Linux-specific.
NOTES¶
Not all of the attributes that can be shared when a new thread is created using
clone(2) can be changed using
setns().
BUGS¶
The PID namespace and the mount namespace are not currently supported. (See the
descriptions of
CLONE_NEWPID and
CLONE_NEWNS in
clone(2).)
SEE ALSO¶
clone(2),
fork(2),
vfork(2),
proc(5),
unix(7)
COLOPHON¶
This page is part of release 3.44 of the Linux
man-pages project. A
description of the project, and information about reporting bugs, can be found
at
http://www.kernel.org/doc/man-pages/.