CHROOT(2) - phpMan

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

NAME
chroot - change root directory

SYNOPSIS
#include <unistd.h>

int chroot(const char *path);

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 direc-
tory 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 appropri-
ately.

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.