(*

Module: Cron

 Parses /etc/cron.d/*, /etc/crontab

Author: Raphael Pinson <raphink@gmail.com>

About: Reference

 This lens tries to keep as close as possible to `man 5 crontab` where

 possible.

About: License

  This file is licensed under the LGPL v2+, like the rest of Augeas.

About: Lens Usage

  Sample usage of this lens in augtool

    * Get the entry that launches '/usr/bin/ls'

      >  match '/files/etc/crontab/entry[. = "/usr/bin/ls"]'

About: Configuration files

  This lens applies to /etc/cron.d/* and /etc/crontab. See <filter>.

*)

module Cron =

  autoload xfm

(************************************************************************

 * Group:                 USEFUL PRIMITIVES

 *************************************************************************)

(* Group: Generic primitives *)

(* Variable: eol *)

let eol     = Util.eol

(* Variable: indent *)

let indent  = Util.indent

(* Variable: comment *)

let comment = Util.comment

(* Variable: empty *)

let empty   = Util.empty

(* Variable: num *)

let num        = /[0-9*][0-9\/,*-]*/

(* Variable: alpha *)

let alpha      = /[A-Za-z]{3}/

(* Variable: alphanum *)

let alphanum   = (num|alpha) . ("-" . (num|alpha))?

(* Variable: entry_prefix *)

let entry_prefix = /-/

(* Group: Separators *)

(* Variable: sep_spc *)

let sep_spc = Util.del_ws_spc

(* Variable: sep_eq *)

let sep_eq  = Util.del_str "="

(************************************************************************

 * Group:                       ENTRIES

 *************************************************************************)

(************************************************************************

 * View: shellvar

 *   A shell variable in crontab

 *************************************************************************)

let shellvar =

  let key_re = /[A-Za-z1-9_-]+(\[[0-9]+\])?/ - "entry" in

  let sto_to_eol = store /[^\n]*[^ \t\n]/ in

  [ key key_re . sep_eq . sto_to_eol . eol ]

(* View: - prefix of an entry *)

let prefix     = [ label "prefix"       . store entry_prefix ]

(* View: minute *)

let minute     = [ label "minute"       . store num ]

(* View: hour *)

let hour       = [ label "hour"         . store num ]

(* View: dayofmonth *)

let dayofmonth = [ label "dayofmonth" . store num ]

(* View: month *)

let month      = [ label "month"        . store alphanum ]

(* View: dayofweek *)

let dayofweek  = [ label "dayofweek"  . store alphanum ]

(* View: user *)

let user       = [ label "user"         . store Rx.word ]

(************************************************************************

 * View: time

 *   Time in the format "minute hour dayofmonth month dayofweek"

 *************************************************************************)

let time        = [ label "time" .

                  minute . sep_spc . hour  . sep_spc . dayofmonth

                         . sep_spc . month . sep_spc . dayofweek ]

(* Variable: the valid values for schedules *)

let schedule_re = "reboot" | "yearly" | "annually" | "monthly"

                | "weekly" | "daily"  | "midnight" | "hourly"

(************************************************************************

 * View: schedule

 *   Time in the format "@keyword"

 *************************************************************************)

let schedule    = [ label "schedule" . Util.del_str "@"

                   . store schedule_re ]

(************************************************************************

 * View: entry

 *   A crontab entry

 *************************************************************************)

let entry       = [ label "entry" . indent

                   . prefix?

                   . ( time | schedule )

                   . sep_spc . user

                   . sep_spc . store Rx.space_in . eol ]

(*

 * View: lns

 *   The cron lens

 *)

let lns = ( empty | comment | shellvar | entry )*

(* Variable: filter *)

let filter =

  incl "/etc/cron.d/*" .

  incl "/etc/crontab" .

  incl "/etc/crontabs/*" .

  excl "/etc/cron.d/at.allow" .

  excl "/etc/cron.d/at.deny" .

  excl "/etc/cron.d/cron.allow" .

  excl "/etc/cron.d/cron.deny" .

  Util.stdexcl

let xfm = transform lns filter