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--
-- gcsd
--
-- gcsd the generic command sequencer daemon can be used to serialize
-- commands sent over various paralell communication channels to a
-- single command output. It can be seen as a multiplexer for any
-- kind of communication between a single resource and various clients
-- which want to submit commands to it or query information from it.
-- gcsd is written in C and Lua. The goal is to provide an easy to
-- understand high level API based on Lua which can be used to
-- implement the business logic of the so formed multiplexer daemon.
--
--
-- Copyright (C) 2009-2010 Markus Grueneis <gimpf@spreadspace.org>
-- Christian Pointner <equinox@spreadspace.org>
--
-- This file is part of gcsd.
--
-- gcsd is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- any later version.
--
-- gcsd is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with gcsd. If not, see <http://www.gnu.org/licenses/>.
--
local defines = require("defines")
-- exec module class
local exec = {}
exec.properties = { type=defines.INOUT_MODULE, name="exec", max_instances=-1 }
exec.defaults = { script = "exec.sh" }
exec.next_id = 0
-- create new instance of exec module class
function exec:new(config)
local inst = {}
inst.class = self.properties.name
inst.config = config
if(config.name == nil or config.name == "") then
inst.name = self.properties.name .. self.next_id
self.next_id = self.next_id + 1
else
inst.name = config.name
end
if(not config.script) then config.script = self.defaults.script end
local reader, writer_child = util.pipe()
if(reader == nil) then
log.printf(log.ERROR, inst.name .. ": pipe failed: %s", writer_child)
return nil
end
local reader_child, writer = util.pipe()
if(writer == nil) then
log.printf(log.ERROR, inst.name .. ": pipe failed: %s", reader_child)
return nil
end
local child, err = util.exec(config.script, nil, nil, reader_child, writer_child)
if(child == nil) then
log.printf(log.ERROR, inst.name .. ": exec failed: %s", error)
return nil
end
log.printf(log.NOTICE, inst.name .. ": child spawned with pid %d", child.pid)
local in_handle = {}
in_handle.fd = reader
rawio.setnonblock(in_handle.fd)
in_handle.client_instance = nil
in_handle.in_buffer = ""
function in_handle:getfd() return self.fd end
function in_handle:read()
-- TODO: which size should we request??
local buffer, err = rawio.read(self.fd, 100)
if(buffer == nil) then
log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
return defines.KILL_MODULE_CLASS
end
-- TODO: support read until matched command
self.in_buffer = self.in_buffer .. buffer
-- TODO: dispatch table et al
command_queue:command_completed()
return defines.OK
end
function in_handle:write() end
local out_handle = {}
out_handle.fd = writer
rawio.setnonblock(out_handle.fd)
out_handle.client_instance = nil
out_handle.out_buffer = ""
function out_handle:getfd() return self.fd end
function out_handle:read() end
function out_handle:write()
local len, err = rawio.write(self.fd, self.out_buffer)
if(len == nil) then
log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
ret = defines.KILL_MODULE_CLASS
else
self.out_buffer = string.sub(self.out_buffer, len+1)
end
if(self.out_buffer == "") then
command_queue:command_sent()
end
return defines.OK
end
local client = {}
client.module_instance = inst
client.name = inst.name .. "#0"
client.pid = child.pid
function client:process_response() end
function client:process_timeout() end
function client:get_read_handles()
return { in_handle }
end
function client:get_write_handles()
if(out_handle.out_buffer ~= "") then
return { out_handle }
else
return {}
end
end
function client:cleanup()
util.kill(self.pid)
end
in_handle.client_instance = client
out_handle.client_instance = client
function inst:cleanup()
client_list:unregister_by_module(self)
end
function inst:get_read_handles()
return {}
end
function inst:get_write_handles()
return {}
end
function inst:start_command(command)
out_handle.out_buffer = command
end
setmetatable(inst, {})
getmetatable(inst).__gc = function() inst:cleanup() end
client_list:register(client)
return inst
end
return exec
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