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 effective user	ID of the process must be  super-user  to
     change  the  root	directory. While it is always possible to
     change to the system root using the fchroot()  function,  it
     is	 not guaranteed	to succeed in any other	case, even should
     fildes be 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 outside the subtree rooted at	the  root  direc-
     tory.  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 permission 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 external



SunOS 5.7	     Last change: 4 May	1994			1






System Calls						chroot(2)



	       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  writ-
	       ing 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 directory.

     EPERM     The effective user of the calling process  is  not
	       super-user.

SEE ALSO
     chroot(1M), chdir(2)

WARNINGS
     The only use of fchroot() that is appropriate is  to  change
     back to the system	root.






















SunOS 5.7	     Last change: 4 May	1994			2