Parses /etc/hosts.{allow,deny}
Author: Raphael Pinson rap@gmai l.com hink
Hosts_Access | Parses /etc/hosts.{allow,deny} |
Reference | This lens tries to keep as close as possible to `man 5 hosts_access` and `man 5 hosts_options` where possible. |
License | This file is licenced under the LGPL v2+, like the rest of Augeas. |
Lens Usage | To be documented |
Configuration files | This lens applies to /etc/hosts.{allow,deny}. |
USEFUL PRIMITIVES | |
colon | |
comma_sep | |
ws_sep | |
list_sep | |
list_item | |
client_host_item | Allows @ for netgroups, supports [ipv6] syntax |
client_file_item | |
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 |
shell_command_rx | |
sto_to_colon | Allows escaped colon sequences |
except | The except operator makes it possible to write very compact rules. |
ENTRY TYPES | |
daemon | |
daemon_list | A list of daemons |
client | |
client_file | |
client_list | A list of clients |
option | Optional extensions defined in hosts_options(5) |
shell_command | |
entry | |
LENS AND FILTER | |
lns | |
filter |
This lens applies to /etc/hosts.{allow,deny}. See filter.
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?
Allows @ for netgroups, supports [ipv6] syntax
let option_kw = "severity" | "spawn" | "twist" | "keepalive" | "linger" | "rfc931" | "banners" | "nice" | "setenv" | "umask" | "user" | /allow/i | /deny/i
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 daemon_list = Build.opt_list daemon list_sep
A list of daemons
let client_list = Build.opt_list ( client | client_file ) list_sep
A list of clients
let colon = del /[ \t]*(\\\\[ \t]*\n[ \t]+)?:[ \t]*(\\\\[ \t]*\n[ \t]+)?/ ": "
let comma_sep = /([ \t]|(\\\\\n))*,([ \t]|(\\\\\n))*/
let ws_sep = / +/
let list_sep = del ( comma_sep | ws_sep ) ", "
let list_item = store ( Rx.word - /EXCEPT/i )
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?
let client_file_item = let client_file_rx = /\/[^ \t\n,:]+/ in store ( client_file_rx - /EXCEPT/i )
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
let shell_command_rx = /[^ \t\n:][^\n]*[^ \t\n]|[^ \t\n:\\\\]/ - ( option_kw . /.*/ )
Allows escaped colon sequences
let sto_to_colon = store /[^ \t\n:=][^\n:]*((\\\\:|\\\\[ \t]*\n[ \t]+)[^\n:]*)*[^ \\\t\n:]|[^ \t\n:\\\\]/
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 ]
let daemon = let host = [ label "host" . Util.del_str "@" . list_item ] in [ label "process" . list_item . host? ]
A list of daemons
let daemon_list = Build.opt_list daemon list_sep
let client = let user = [ label "user" . list_item . Util.del_str "@" ] in [ label "client" . user? . client_host_item ]
let client_file = [ label "file" . client_file_item ]
A list of clients
let client_list = Build.opt_list ( client | client_file ) list_sep
Optional extensions defined in hosts_options(5)
let option = [ key option_kw . ( del /([ \t]*=[ \t]*|[ \t]+)/ " " . sto_to_colon )? ]
let shell_command = [ label "shell_command" . store shell_command_rx ]
let entry = [ seq "line" . daemon_list . (except daemon_list)? . colon . client_list . (except client_list)? . ( (colon . option)+ | (colon . shell_command)? ) . Util.eol ]
let lns = (Util.empty | Util.comment | entry)*