NAME    [Toc]    [Back]

     chroot - change root directory

SYNOPSIS    [Toc]    [Back]

     #include <unistd.h>

     int
     chroot(const char *dirname);

DESCRIPTION    [Toc]    [Back]

     dirname is the address of the pathname of a directory,  terminated by an
     ASCII  NUL.   chroot() causes dirname to become the root directory, that
     is, the starting point for path searches of pathnames beginning with `/'.

     In order for a directory to become the root directory a process must have
     execute (search) access for that directory.

     If the program is not currently running with an altered root
directory,
     it  should  be noted that chroot() has no effect on the process's current
     directory.

     If the program is already running with an altered  root  directory, the
     process's  current directory is changed to the same new root
directory.
     This prevents the current directory from  being  further  up
the directory
     tree than the altered root directory.

     This call is restricted to the superuser.

RETURN VALUES    [Toc]    [Back]

     Upon  successful completion, a value of 0 is returned.  Otherwise, a value
     of -1 is returned and errno is set to indicate an error.

ERRORS    [Toc]    [Back]

     chroot() will fail and the root directory will be  unchanged
if:

     [ENOTDIR]     A component of the path name is not a directory.

     [ENAMETOOLONG]
                   A component of a pathname exceeded  {NAME_MAX}
characters,
                   or  an  entire  path  name exceeded {PATH_MAX}
characters.

     [ENOENT]      The named directory does not exist.

     [EACCES]      Search permission is denied for any  component
of the path
                   name.

     [ELOOP]        Too  many  symbolic links were encountered in
translating the
                   pathname.

     [EFAULT]      dirname points outside the process's allocated
address
                   space.

     [EIO]          An  I/O  error occurred while reading from or
writing to the
                   file system.

     [EPERM]       The caller is not the superuser.

SEE ALSO    [Toc]    [Back]

     chdir(2)

WARNINGS    [Toc]    [Back]

     There are ways for a root process to escape from the  chroot
jail.

HISTORY    [Toc]    [Back]

     The chroot() function call appeared in 4.2BSD.

OpenBSD      3.6                           June      4,      1993