added initial exec module

git-svn-id: https://svn.spreadspace.org/gcsd/trunk@52 ac14a137-c7f1-4531-abe0-07747231d213

1 files changed, 155 insertions, 0 deletions

diff --git a/src/modules/exec.lua b/src/modules/exec.lua
new file mode 100644
index 0000000..b819b6f
--- /dev/null
+++ b/src/modules/exec.lua
@@ -0,0 +1,155 @@
+--
+--  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" }
+
+-- 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
+   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 pid, err = util.exec(config.script, nil, nil, reader_child, writer_child)
+   if(pid == 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", 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 = 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() 
+      -- TODO: kill child
+   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