debian man page for setns

SETNS(2)						     Linux Programmer's Manual							  SETNS(2)

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 fol-
       lowing 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.

CONFORMING TO
       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/.

Linux								    2012-05-04								  SETNS(2)