Index: head/lib/libc/sys/chroot.2
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--- head/lib/libc/sys/chroot.2	(revision 362663)
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@@ -1,158 +1,158 @@
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 .\"     @(#)chroot.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd March 30, 2020
+.Dd June 26, 2020
 .Dt CHROOT 2
 .Os
 .Sh NAME
 .Nm chroot
 .Nd change root directory
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
 .In unistd.h
 .Ft int
 .Fn chroot "const char *dirname"
 .Sh DESCRIPTION
 The
 .Fa dirname
 argument
 is the address of the pathname of a directory, terminated by an ASCII NUL.
 The
 .Fn chroot
 system call causes
 .Fa dirname
 to become the root directory,
 that is, the starting point for path searches of pathnames
 beginning with
 .Ql / .
 .Pp
 In order for a directory to become the root directory
 a process must have execute (search) access for that directory.
 .Pp
 It should be noted that
 .Fn chroot
 has no effect on the process's current directory.
 .Pp
 This call is restricted to the super-user.
 .Pp
 Depending on the setting of the
 .Ql kern.chroot_allow_open_directories
 sysctl variable, open filedescriptors which reference directories
 will make the
 .Fn chroot
 fail as follows:
 .Pp
 If
 .Ql kern.chroot_allow_open_directories
 is set to zero,
 .Fn chroot
 will always fail with
 .Er EPERM
 if there are any directories open.
 .Pp
 If
 .Ql kern.chroot_allow_open_directories
 is set to one (the default),
 .Fn chroot
 will fail with
 .Er EPERM
 if there are any directories open and the
 process is already subject to the
 .Fn chroot
 system call.
 .Pp
 Any other value for
 .Ql kern.chroot_allow_open_directories
 will bypass the check for open directories
 .Sh RETURN VALUES
 .Rv -std
 .Sh ERRORS
 The
 .Fn chroot
 system call
 will fail and the root directory will be unchanged if:
 .Bl -tag -width Er
 .It Bq Er ENOTDIR
 A component of the path name is not a directory.
 .It Bq Er EPERM
 The effective user ID is not the super-user, or one or more
 filedescriptors are open directories.
 .It Bq Er ENAMETOOLONG
 A component of a pathname exceeded 255 characters,
 or an entire path name exceeded 1023 characters.
 .It Bq Er ENOENT
 The named directory does not exist.
 .It Bq Er EACCES
 Search permission is denied for any component of the path name.
 .It Bq Er ELOOP
 Too many symbolic links were encountered in translating the pathname.
 .It Bq Er EFAULT
 The
 .Fa dirname
 argument
 points outside the process's allocated address space.
 .It Bq Er EIO
 An I/O error occurred while reading from or writing to the file system.
 .It Bq Er EINTEGRITY
 Corrupted data was detected while reading from the file system.
 .El
 .Sh SEE ALSO
 .Xr chdir 2 ,
 .Xr jail 2
 .Sh HISTORY
 The
 .Fn chroot
 system call appeared in
-.Bx 4.2 .
+.At v7 .
 It was marked as
 .Dq legacy
 in
 .St -susv2 ,
 and was removed in subsequent standards.
 .Sh BUGS
 If the process is able to change its working directory to the target
 directory, but another access control check fails (such as a check for
 open directories, or a MAC check), it is possible that this system
 call may return an error, with the working directory of the process
 left changed.
 .Sh SECURITY CONSIDERATIONS
 The system have many hardcoded paths to files where it may load after
 the process starts.
 It is generally recommended to drop privileges immediately after a
 successful
 .Nm
 call,
 and restrict write access to a limited subtree of the
 .Nm
 root,
 for instance,
 setup the sandbox so that the sandboxed user will have no write
 access to any well-known system directories.