Name

chroot — change root directory

Synopsis

#include <unistd.h>
int chroot( const char *path);
 
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
chroot():
Since glibc 2.2.2:
_BSD_SOURCE || (_XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) && !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
Before glibc 2.2.2:
none

DESCRIPTION

chroot() changes the root directory of the calling process to that specified in path. This directory will be used for pathnames beginning with /. The root directory is inherited by all children of the calling process.

Only a privileged process (Linux: one with the CAP_SYS_CHROOT capability) may call chroot().

This call changes an ingredient in the pathname resolution process and does nothing else.

This call does not change the current working directory, so that after the call '.' can be outside the tree rooted at '/'. In particular, the superuser can escape from a "chroot jail" by doing:

    mkdir foo; chroot foo; cd ..

This call does not close open file descriptors, and such file descriptors may allow access to files outside the chroot tree.

RETURN VALUE

On success, zero is returned. On error, −1 is returned, and errno is set appropriately.

ERRORS

Depending on the file system, other errors can be returned. The more general errors are listed below:

EACCES

Search permission is denied on a component of the path prefix. (See also path_resolution(7).)

EFAULT

path points outside your accessible address space.

EIO

An I/O error occurred.

ELOOP

Too many symbolic links were encountered in resolving path.

ENAMETOOLONG

path is too long.

ENOENT

The file does not exist.

ENOMEM

Insufficient kernel memory was available.

ENOTDIR

A component of path is not a directory.

EPERM

The caller has insufficient privilege.

CONFORMING TO

SVr4, 4.4BSD, SUSv2 (marked LEGACY). This function is not part of POSIX.1-2001.

NOTES

A child process created via fork(2) inherits its parent's root directory. The root directory is left unchanged by execve(2).

FreeBSD has a stronger jail() system call.

SEE ALSO

chdir(2), path_resolution(7)

COLOPHON

This page is part of release 3.52 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/.


  Copyright (c) 1992 Drew Eckhardt (drewcs.colorado.edu), March 28, 1992

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Modified by Michael Haardt <michaelmoria.de>
Modified 1993-07-21 by Rik Faith <faithcs.unc.edu>
Modified 1994-08-21 by Michael Chastain <mecshell.portal.com>
Modified 1996-06-13 by aeb
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Modified 1997-08-21 by Joseph S. Myers <jsm28cam.ac.uk>
Modified 2004-06-23 by Michael Kerrisk <mtk.manpagesgmail.com>