chroot(2) System Calls chroot(2)NAME
chroot, fchroot - change root directory
SYNOPSIS
#include <unistd.h>
int chroot(const char *path);
int fchroot(int fildes);
DESCRIPTION
The chroot() and fchroot() functions cause a directory to become the
root directory, the starting point for path searches for path names
beginning with / (slash). The user's working directory is unaffected by
the chroot() and fchroot() functions.
The path argument points to a path name naming a directory. The fildes
argument to fchroot() is the open file descriptor of the directory
which is to become the root.
The privilege {PRIV_PROC_CHROOT} must be asserted in the effective set
of the process to change the root directory. While it is always possi‐
ble to change to the system root using the fchroot() function, it is
not guaranteed to succeed in any other case, even if fildes is valid in
all respects.
The ".." entry in the root directory is interpreted to mean the root
directory itself. Therefore, ".." cannot be used to access files out‐
side the subtree rooted at the root directory. Instead, fchroot() can
be used to reset the root to a directory that was opened before the
root directory was changed.
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, −1 is returned,
the root directory remains unchanged, and errno is set to indicate the
error.
ERRORS
The chroot() function will fail if:
EACCES Search permission is denied for a component of
the path prefix of dirname, or search permis‐
sion is denied for the directory referred to by
dirname.
EBADF The descriptor is not valid.
EFAULT The path argument points to an illegal address.
EINVAL The fchroot() function attempted to change to a
directory the is not the system root and exter‐
nal circumstances do not allow this.
EINTR A signal was caught during the execution of the
chroot() function.
EIO An I/O error occurred while reading from or
writing to the file system.
ELOOP Too many symbolic links were encountered in
translating path.
ENAMETOOLONG The length of the path argument exceeds
PATH_MAX, or the length of a path component
exceeds NAME_MAX while _POSIX_NO_TRUNC is in
effect.
ENOENT The named directory does not exist or is a null
pathname.
ENOLINK The path argument points to a remote machine
and the link to that machine is no longer
active.
ENOTDIR Any component of the path name is not a direc‐
tory.
EPERM The {PRIV_PROC_CHROOT} privilege is not
asserted in the effective set of the calling
process.
SEE ALSOchroot(1M), chdir(2), privileges(5)WARNINGS
The only use of fchroot() that is appropriate is to change back to the
system root.
SunOS 5.10 20 Jan 2003 chroot(2)
