(*
Module: Syslog
parses /etc/syslog.conf
Author: Mathieu Arnold <mat@FreeBSD.org>
About: Reference
This lens tries to keep as close as possible to `man 5 resolv.conf` where possible.
An online source being :
http://www.freebsd.org/cgi/man.cgi?query=syslog.conf&sektion=5
About: Licence
This file is licensed under the BSD License.
About: Lens Usage
To be documented
About: Configuration files
This lens applies to /etc/syslog.conf. See <filter>.
*)
module Syslog =
autoload xfm
(************************************************************************
* Group: USEFUL PRIMITIVES
*************************************************************************)
(* Group: Comments and empty lines *)
(* Variable: empty *)
let empty = Util.empty
(* Variable: eol *)
let eol = Util.eol
(* Variable: sep_tab *)
let sep_tab = del /([ \t]+|[ \t]*\\\\\n[ \t]*)/ "\t"
(* Variable: sep_tab_opt *)
let sep_tab_opt = del /([ \t]*|[ \t]*\\\\\n[ \t]*)/ ""
(* View: comment
Map comments into "#comment" nodes
Can't use Util.comment as #+ and #! have a special meaning.
However, '# !' and '# +' have no special meaning so they should be allowed.
*)
let comment_gen (space:regexp) (sto:regexp) =
[ label "#comment" . del (Rx.opt_space . "#" . space) "# "
. store sto . eol ]
let comment =
let comment_withsign = comment_gen Rx.space /([!+-].*[^ \t\n]|[!+-])/
in let comment_nosign = comment_gen Rx.opt_space /([^ \t\n+!-].*[^ \t\n]|[^ \t\n+!-])/
in comment_withsign | comment_nosign
(* Group: single characters macro *)
(* Variable: comma
Deletes a comma and default to it
*)
let comma = sep_tab_opt . Util.del_str "," . sep_tab_opt
(* Variable: colon
Deletes a colon and default to it
*)
let colon = sep_tab_opt . Util.del_str ":" . sep_tab_opt
(* Variable: semicolon
Deletes a semicolon and default to it
*)
let semicolon = sep_tab_opt . Util.del_str ";" . sep_tab_opt
(* Variable: dot
Deletes a dot and default to it
*)
let dot = Util.del_str "."
(* Variable: pipe
Deletes a pipe and default to it
*)
let pipe = Util.del_str "|"
(* Variable: plus
Deletes a plus and default to it
*)
let plus = Util.del_str "+"
(* Variable: bang
Deletes a bang and default to it
*)
let bang = Util.del_str "!"
(* Variable: opt_hash
deletes an optional # sign
*)
let opt_hash = del /#?/ ""
(* Variable: opt_plus
deletes an optional + sign
*)
let opt_plus = del /\+?/ ""
(* Group: various macros *)
(* Variable: word
our version can't start with [_.-] because it would mess up the grammar
*)
let word = /[A-Za-z0-9][A-Za-z0-9_.-]*/
(* Variable: comparison
a comparison is an optional ! with optionally some of [<=>]
*)
let comparison = /(!|[<=>]+|![<=>]+)/
(* Variable: protocol
@ means UDP
@@ means TCP
*)
let protocol = /@{1,2}/
(* Variable: token
alphanum or "*"
*)
let token = /([A-Za-z0-9]+|\*)/
(* Variable: file_r
a file begins with a / and get almost anything else after
*)
let file_r = /\/[^ \t\n;]+/
(* Variable: loghost_r
Matches a hostname, that is labels speparated by dots, labels can't
start or end with a "-". maybe a bit too complicated for what it's worth *)
let loghost_r = /[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?(\.[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?)*/ |
"[" . Rx.ipv6 . "]"
(* Group: Function *)
(* View: label_opt_list
Uses Build.opt_list to generate a list of labels
Parameters:
l:string - the label name
r:lens - the lens going after the label
s:lens - the separator lens passed to Build.opt_list
*)
let label_opt_list (l:string) (r:lens) (s:lens) = Build.opt_list [ label l . r ] s
(* View: label_opt_list_or
Either label_opt_list matches something or it emits a single label
with the "or" string.
Parameters:
l:string - the label name
r:lens - the lens going after the label
s:lens - the separator lens passed to Build.opt_list
or:string - the string used if the label_opt_list does not match anything
*)
let label_opt_list_or (l:string) (r:lens) (s:lens) (or:string) =
( label_opt_list l r s | [ label l . store or ] )
(************************************************************************
* Group: LENSE DEFINITION
*************************************************************************)
(* Group: selector *)
(* View: facilities
a list of facilities, separated by commas
*)
let facilities = label_opt_list "facility" (store token) comma
(* View: selector
a selector is a list of facilities, an optional comparison and a level
*)
let selector = facilities . dot .
[ label "comparison" . store comparison]? .
[ label "level" . store token ]
(* View: selectors
a list of selectors, separated by semicolons
*)
let selectors = label_opt_list "selector" selector semicolon
(* Group: action *)
(* View: file
a file may start with a "-" meaning it does not gets sync'ed everytime
*)
let file = [ Build.xchgs "-" "no_sync" ]? . [ label "file" . store file_r ]
(* View: loghost
a loghost is an @ sign followed by the hostname and a possible port
*)
let loghost = [label "protocol" . store protocol] . [ label "hostname" . store loghost_r ] .
(colon . [ label "port" . store /[0-9]+/ ] )?
(* View: users
a list of users or a "*"
*)
let users = label_opt_list_or "user" (store word) comma "*"
(* View: logprogram
a log program begins with a pipe
*)
let logprogram = pipe . [ label "program" . store /[^ \t\n][^\n]+[^ \t\n]/ ]
(* View: discard
discards matching messages
*)
let discard = [ label "discard" . Util.del_str "~" ]
(* View: action
an action is either a file, a host, users, a program, or discard
*)
let action = (file | loghost | users | logprogram | discard)
(* Group: Entry *)
(* View: entry
an entry contains selectors and an action
*)
let entry = [ label "entry" .
selectors . sep_tab .
[ label "action" . action ] . eol ]
(* View: entries
entries are either comments/empty lines or entries
*)
let entries = (empty | comment | entry )*
(* Group: Program matching *)
(* View: programs
a list of programs
*)
let programs = label_opt_list_or "program" (store word) comma "*"
(* View: program
a program begins with an optional hash, a bang, and an optional + or -
*)
let program = [ label "program" . opt_hash . bang .
( opt_plus | [ Build.xchgs "-" "reverse" ] ) .
programs . eol . entries ]
(* Group: Hostname maching *)
(* View: hostnames
a list of hostnames
*)
let hostnames = label_opt_list_or "hostname" (store Rx.word) comma "*"
(* View: hostname
a program begins with an optional hash, and a + or -
*)
let hostname = [ label "hostname" . opt_hash .
( plus | [ Build.xchgs "-" "reverse" ] ) .
hostnames . eol . entries ]
(* Group: Top of the tree *)
let include =
[ key "include" . sep_tab . store file_r . eol ]
(* View: lns
generic entries then programs or hostnames matching blocs
*)
let lns = entries . ( program | hostname | include )*
(* Variable: filter
all you need is /etc/syslog.conf
*)
let filter = incl "/etc/syslog.conf"
let xfm = transform lns filter