(* Lens for Linux syntax of NFS exports(5) *)

(*

Module: Exports

    Parses /etc/exports

Author: David Lutterkort <lutter@redhat.com>

About: Description

    /etc/exports contains lines associating a directory with one or

    more hosts, and NFS options for each host.

About: Usage Example

(start code)

    $ augtool

    augtool> ls /files/etc/exports/

    comment[1] = /etc/exports: the access control list for filesystems which may be exported

    comment[2] = to NFS clients.  See exports(5).

    comment[3] = sample /etc/exports file

    dir[1]/ = /

    dir[2]/ = /projects

    dir[3]/ = /usr

    dir[4]/ = /home/joe

    augtool> ls /files/etc/exports/dir[1]

    client[1]/ = master

    client[2]/ = trusty

(end code)

The corresponding line in the file is:

(start code)

	/               master(rw) trusty(rw,no_root_squash)

(end code)

    Digging further:

(start code)

    augtool> ls /files/etc/exports/dir[1]/client[1]

    option = rw

    To add a new entry, you'd do something like this:

(end code)

(start code)

    augtool> set /files/etc/exports/dir[10000] /foo

    augtool> set /files/etc/exports/dir[last()]/client[1] weeble

    augtool> set /files/etc/exports/dir[last()]/client[1]/option[1] ro

    augtool> set /files/etc/exports/dir[last()]/client[1]/option[2] all_squash

    augtool> save

    Saved 1 file(s)

(end code)

    Which creates the line:

(start code)

    /foo weeble(ro,all_squash)

(end code)

About: Limitations

    This lens cannot handle options without a host, as with the last

    example line in "man 5 exports":

	/pub            (ro,insecure,all_squash)

    In this case, though, you can just do:

	/pub            *(ro,insecure,all_squash)

    It also can't handle whitespace before the directory name.

*)

module Exports =

  autoload xfm

  let client_re = /[][a-zA-Z0-9.@*?\/:-]+/

  let eol = Util.eol

  let lbracket  = Util.del_str "("

  let rbracket  = Util.del_str ")"

  let sep_com   = Sep.comma

  let sep_spc   = Sep.space

  let option = [ label "option" . store /[^,)]*/ ]

  let client    = [ label "client" . store client_re .

                    ( Build.brackets lbracket rbracket

                         ( Build.opt_list option sep_com ) )? ]

  let entry = [ label "dir" . store /[^ \t\n#]*/

                . sep_spc . Build.opt_list client sep_spc . eol ]

  let lns = (Util.empty | Util.comment | entry)*

  let xfm = transform lns (incl "/etc/exports")