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-- lib/lace/builtin.lua
--
-- Lua Access Control Engine -- Builtin commands for Lace
--
-- Copyright 2012 Daniel Silverstone <dsilvers@digital-scurf.org>
--
-- For Licence terms, see COPYING
--
local builtin = {}
local engine = require "lace.engine"
local function compiler()
return require "lace.compiler"
end
--[ Allow and Deny ]------------------------------------------------
local unconditional_result, last_result
local function get_set_last_unconditional_result(newv)
local ret = unconditional_result
unconditional_result = newv
return ret
end
local function get_set_last_result(newv)
local ret = last_result
last_result = newv
return ret
end
local function _do_return(exec_context, result, reason, cond)
for i = 1, #cond do
local name = cond[i]
local invert = false
if name:sub(1,1) == "!" then
invert = true
name = name:sub(2)
end
local res, msg = engine.test(exec_context, name)
if res == nil then
return nil, msg
end
if invert then
res = not res
end
if not res then
-- condition failed, return true to continue execution
return true
end
end
return result, reason
end
local function _return(compcontext, result, reason, ...)
if result ~= "allow" and result ~= "deny" then
return compiler().error("Unknown result: " .. result, {1})
end
if type(reason) ~= "string" then
return compiler().error("Expected reason, got nothing")
end
local cond = {...}
if #cond == 0 then
unconditional_result = result
end
last_result = result
return {
fn = _do_return,
args = { result, reason, cond }
}
end
builtin.allow = _return
builtin.deny = _return
--[ Default for Allow and Deny ]------------------------------------
function builtin.default(compcontext, def, result, reason, unwanted)
assert(def == "default", "Somehow, builtin.default got something odd")
if type(result) ~= "string" then
return compiler().error("Expected result, got nothing")
end
if result ~= "allow" and result ~= "deny" then
return compiler().error("Result wasn't allow or deny", {2})
end
if type(reason) ~= "string" then
reason = "Default behaviour"
end
if unwanted ~= nil then
return compiler().error("Unexpected additional content", {4})
end
if compcontext[".lace"].default then
return compiler().error("Cannot change the default")
end
local uncond, last = unconditional_result, last_result
compcontext[".lace"].default = _return(compcontext, result, reason)
unconditional_result, last_result = uncond, last
return {
fn = function() return true end,
args = {}
}
end
--[ Definitions ]----------------------------------------------------
local function _controlfn(ctx, name)
local ctt = ctx[".lace"].controltype or {}
return ctt[name]
end
function builtin.define(compcontext, define, name, controltype, ...)
if type(name) ~= "string" then
return compiler().error("Expected name, got nothing")
end
if name == "" or name:sub(1,1) == "!" then
return compiler().error("Bad name for definition", {2})
end
if type(controltype) ~= "string" then
return compiler().error("Expected control type, got nothing")
end
local controlfn = _controlfn(compcontext, controltype)
if not controlfn then
return compiler().error("Unknown control type", {3})
end
local ctrltab, msg = controlfn(compcontext, controltype, ...)
if type(ctrltab) ~= "table" then
-- offset all the words in the error by 2 (for define and name)
if msg.words then
for i = 1, #msg.words do
msg.words[i] = msg.words[i] + 2
end
end
return false, msg
end
-- Successfully created a control table, return a rule for it
return {
fn = engine.define,
args = { name, ctrltab }
}
end
builtin.def = builtin.define
return {
commands = builtin,
get_set_last_unconditional_result = get_set_last_unconditional_result,
get_set_last_result = get_set_last_result,
}
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