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Mini Shell
Mini Shell
(*
Module: Hosts_Access
Parses /etc/hosts.{allow,deny}
Author: Raphael Pinson <raphink@gmail.com>
About: Reference
This lens tries to keep as close as possible to `man 5 hosts_access` and `man 5 hosts_options` where possible.
About: License
This file is licenced under the LGPL v2+, like the rest of Augeas.
About: Lens Usage
To be documented
About: Configuration files
This lens applies to /etc/hosts.{allow,deny}. See <filter>.
*)
module Hosts_Access =
autoload xfm
(************************************************************************
* Group: USEFUL PRIMITIVES
*************************************************************************)
(* View: colon *)
let colon = del /[ \t]*(\\\\[ \t]*\n[ \t]+)?:[ \t]*(\\\\[ \t]*\n[ \t]+)?/ ": "
(* Variable: comma_sep *)
let comma_sep = /([ \t]|(\\\\\n))*,([ \t]|(\\\\\n))*/
(* Variable: ws_sep *)
let ws_sep = / +/
(* View: list_sep *)
let list_sep = del ( comma_sep | ws_sep ) ", "
(* View: list_item *)
let list_item = store ( Rx.word - /EXCEPT/i )
(* View: client_host_item
Allows @ for netgroups, supports [ipv6] syntax *)
let client_host_item =
let client_hostname_rx = /[A-Za-z0-9_.@?*-][A-Za-z0-9_.?*-]*/ in
let client_ipv6_rx = "[" . /[A-Za-z0-9:?*%]+/ . "]" in
let client_host_rx = client_hostname_rx | client_ipv6_rx in
let netmask = [ Util.del_str "/" . label "netmask" . store Rx.word ] in
store ( client_host_rx - /EXCEPT/i ) . netmask?
(* View: client_file_item *)
let client_file_item =
let client_file_rx = /\/[^ \t\n,:]+/ in
store ( client_file_rx - /EXCEPT/i )
(* Variable: option_kw
Since either an option or a shell command can be given, use an explicit list
of known options to avoid misinterpreting a command as an option *)
let option_kw = "severity"
| "spawn"
| "twist"
| "keepalive"
| "linger"
| "rfc931"
| "banners"
| "nice"
| "setenv"
| "umask"
| "user"
| /allow/i
| /deny/i
(* Variable: shell_command_rx *)
let shell_command_rx = /[^ \t\n:][^\n]*[^ \t\n]|[^ \t\n:\\\\]/
- ( option_kw . /.*/ )
(* View: sto_to_colon
Allows escaped colon sequences *)
let sto_to_colon = store /[^ \t\n:=][^\n:]*((\\\\:|\\\\[ \t]*\n[ \t]+)[^\n:]*)*[^ \\\t\n:]|[^ \t\n:\\\\]/
(* View: except
* The except operator makes it possible to write very compact rules.
*)
let except (lns:lens) = [ label "except" . Sep.space
. del /except/i "EXCEPT"
. Sep.space . lns ]
(************************************************************************
* Group: ENTRY TYPES
*************************************************************************)
(* View: daemon *)
let daemon =
let host = [ label "host"
. Util.del_str "@"
. list_item ] in
[ label "process"
. list_item
. host? ]
(* View: daemon_list
A list of <daemon>s *)
let daemon_list = Build.opt_list daemon list_sep
(* View: client *)
let client =
let user = [ label "user"
. list_item
. Util.del_str "@" ] in
[ label "client"
. user?
. client_host_item ]
(* View: client_file *)
let client_file = [ label "file" . client_file_item ]
(* View: client_list
A list of <client>s *)
let client_list = Build.opt_list ( client | client_file ) list_sep
(* View: option
Optional extensions defined in hosts_options(5) *)
let option = [ key option_kw
. ( del /([ \t]*=[ \t]*|[ \t]+)/ " " . sto_to_colon )? ]
(* View: shell_command *)
let shell_command = [ label "shell_command"
. store shell_command_rx ]
(* View: entry *)
let entry = [ seq "line"
. daemon_list
. (except daemon_list)?
. colon
. client_list
. (except client_list)?
. ( (colon . option)+ | (colon . shell_command)? )
. Util.eol ]
(************************************************************************
* Group: LENS AND FILTER
*************************************************************************)
(* View: lns *)
let lns = (Util.empty | Util.comment | entry)*
(* View: filter *)
let filter = incl "/etc/hosts.allow"
. incl "/etc/hosts.deny"
let xfm = transform lns filter
Zerion Mini Shell 1.0