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



NAME
       chroot - change root directory

SYNOPSIS
       #include <unistd.h>

       int chroot(const char *path);

   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  inher‐
       ited 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  filesystem, 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_res‐
              olution(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 direc‐
       tory 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 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2010-09-20                                  CHROOT(2)