flm01/mote/v2/openwrt/package/luci/libs/lucid/luasrc/lucid.lua

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--[[
LuCI - Lua Development Framework
Copyright 2009 Steven Barth <steven@midlink.org>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
$Id$
]]
local nixio = require "nixio"
local table = require "table"
local uci = require "luci.model.uci"
local os = require "os"
local io = require "io"
local pairs, require, pcall, assert, type = pairs, require, pcall, assert, type
local ipairs, tonumber, collectgarbage = ipairs, tonumber, collectgarbage
module "luci.lucid"
local slaves = {}
local pollt = {}
local tickt = {}
local tpids = {}
local tcount = 0
local ifaddrs = nixio.getifaddrs()
cursor = uci.cursor()
state = uci.cursor_state()
UCINAME = "lucid"
local cursor = cursor
local state = state
local UCINAME = UCINAME
local SSTATE = "/tmp/.lucid_store"
--- Starts a new LuCId superprocess.
function start()
prepare()
local detach = cursor:get(UCINAME, "main", "daemonize")
if detach == "1" then
local stat, code, msg = daemonize()
if not stat then
nixio.syslog("crit", "Unable to detach process: " .. msg .. "\n")
ox.exit(2)
end
end
state:set(UCINAME, "main", "pid", nixio.getpid())
state:save(UCINAME)
run()
end
--- Returns the PID of the currently active LuCId process.
function running()
local pid = tonumber(state:get(UCINAME, "main", "pid"))
return pid and nixio.kill(pid, 0) and pid
end
--- Stops any running LuCId superprocess.
function stop()
local pid = tonumber(state:get(UCINAME, "main", "pid"))
if pid then
return nixio.kill(pid, nixio.const.SIGTERM)
end
return false
end
--- Prepares the slaves, daemons and publishers, allocate resources.
function prepare()
local debug = tonumber((cursor:get(UCINAME, "main", "debug")))
nixio.openlog("lucid", "pid", "perror")
if debug ~= 1 then
nixio.setlogmask("warning")
end
cursor:foreach(UCINAME, "daemon", function(config)
if config.enabled ~= "1" then
return
end
local key = config[".name"]
if not config.slave then
nixio.syslog("crit", "Daemon "..key.." is missing a slave\n")
os.exit(1)
else
nixio.syslog("info", "Initializing daemon " .. key)
end
state:revert(UCINAME, key)
local daemon, code, err = prepare_daemon(config)
if daemon then
state:set(UCINAME, key, "status", "started")
nixio.syslog("info", "Prepared daemon " .. key)
else
state:set(UCINAME, key, "status", "error")
state:set(UCINAME, key, "error", err)
nixio.syslog("err", "Failed to initialize daemon "..key..": "..
err .. "\n")
end
end)
end
--- Run the superprocess if prepared before.
-- This main function of LuCId will wait for events on given file descriptors.
function run()
local pollint = tonumber((cursor:get(UCINAME, "main", "pollinterval")))
local threadlimit = tonumber((cursor:get(UCINAME, "main", "threadlimit")))
while true do
local stat, code = nixio.poll(pollt, pollint)
if stat and stat > 0 then
local ok = false
for _, polle in ipairs(pollt) do
if polle.revents ~= 0 and polle.handler then
ok = ok or polle.handler(polle)
end
end
if not ok then
-- Avoid high CPU usage if thread limit is reached
nixio.nanosleep(0, 100000000)
end
elseif stat == 0 then
ifaddrs = nixio.getifaddrs()
collectgarbage("collect")
end
for _, cb in ipairs(tickt) do
cb()
end
local pid, stat, code = nixio.wait(-1, "nohang")
while pid and pid > 0 do
tcount = tcount - 1
if tpids[pid] and tpids[pid] ~= true then
tpids[pid](pid, stat, code)
end
pid, stat, code = nixio.wait(-1, "nohang")
end
end
end
--- Add a file descriptor for the main loop and associate handler functions.
-- @param polle Table containing: {fd = FILE DESCRIPTOR, events = POLL EVENTS,
-- handler = EVENT HANDLER CALLBACK}
-- @see unregister_pollfd
-- @return boolean status
function register_pollfd(polle)
pollt[#pollt+1] = polle
return true
end
--- Unregister a file desciptor and associate handler from the main loop.
-- @param polle Poll descriptor
-- @see register_pollfd
-- @return boolean status
function unregister_pollfd(polle)
for k, v in ipairs(pollt) do
if v == polle then
table.remove(pollt, k)
return true
end
end
return false
end
--- Close all registered file descriptors from main loop.
-- This is useful for forked child processes.
function close_pollfds()
for k, v in ipairs(pollt) do
if v.fd and v.fd.close then
v.fd:close()
end
end
end
--- Register a tick function that will be called at each cycle of the main loop.
-- @param cb Callback
-- @see unregister_tick
-- @return boolean status
function register_tick(cb)
tickt[#tickt+1] = cb
return true
end
--- Unregister a tick function from the main loop.
-- @param cb Callback
-- @see register_tick
-- @return boolean status
function unregister_tick(cb)
for k, v in ipairs(tickt) do
if v == cb then
table.remove(tickt, k)
return true
end
end
return false
end
--- Tests whether a given number of processes can be created.
-- @oaram num Processes to be created
-- @return boolean status
function try_process(num)
local threadlimit = tonumber((cursor:get(UCINAME, "main", "threadlimit")))
return not threadlimit or (threadlimit - tcount) >= (num or 1)
end
--- Create a new child process from a Lua function and assign a destructor.
-- @param threadcb main function of the new process
-- @param waitcb destructor callback
-- @return process identifier or nil, error code, error message
function create_process(threadcb, waitcb)
local threadlimit = tonumber(cursor:get(UCINAME, "main", "threadlimit"))
if threadlimit and tcount >= threadlimit then
nixio.syslog("warning", "Cannot create thread: process limit reached")
return nil
end
local pid, code, err = nixio.fork()
if pid and pid ~= 0 then
tpids[pid] = waitcb
tcount = tcount + 1
elseif pid == 0 then
local code = threadcb()
os.exit(code)
else
nixio.syslog("err", "Unable to fork(): " .. err)
end
return pid, code, err
end
--- Prepare a daemon from a given configuration table.
-- @param config Configuration data.
-- @return boolean status or nil, error code, error message
function prepare_daemon(config)
nixio.syslog("info", "Preparing daemon " .. config[".name"])
local modname = cursor:get(UCINAME, config.slave)
if not modname then
return nil, -1, "invalid slave"
end
local stat, module = pcall(require, _NAME .. "." .. modname)
if not stat or not module.prepare_daemon then
return nil, -2, "slave type not supported"
end
config.slave = prepare_slave(config.slave)
return module.prepare_daemon(config, _M)
end
--- Prepare a slave.
-- @param name slave name
-- @return table containing slave module and configuration or nil, error message
function prepare_slave(name)
local slave = slaves[name]
if not slave then
local config = cursor:get_all(UCINAME, name)
local stat, module = pcall(require, config and config.entrypoint)
if stat then
slave = {module = module, config = config}
end
end
if slave then
return slave
else
return nil, module
end
end
--- Return a list of available network interfaces on the host.
-- @return table returned by nixio.getifaddrs()
function get_interfaces()
return ifaddrs
end
--- Revoke process privileges.
-- @param user new user name or uid
-- @param group new group name or gid
-- @return boolean status or nil, error code, error message
function revoke_privileges(user, group)
if nixio.getuid() == 0 then
return nixio.setgid(group) and nixio.setuid(user)
end
end
--- Return a secure UCI cursor.
-- @return UCI cursor
function securestate()
local stat = nixio.fs.stat(SSTATE) or {}
local uid = nixio.getuid()
if stat.type ~= "dir" or (stat.modedec % 100) ~= 0 or stat.uid ~= uid then
nixio.fs.remover(SSTATE)
if not nixio.fs.mkdir(SSTATE, 700) then
local errno = nixio.errno()
nixio.syslog("err", "Integrity check on secure state failed!")
return nil, errno, nixio.perror(errno)
end
end
return uci.cursor(nil, SSTATE)
end
--- Daemonize the process.
-- @return boolean status or nil, error code, error message
function daemonize()
if nixio.getppid() == 1 then
return
end
local pid, code, msg = nixio.fork()
if not pid then
return nil, code, msg
elseif pid > 0 then
os.exit(0)
end
nixio.setsid()
nixio.chdir("/")
local devnull = nixio.open("/dev/null", nixio.open_flags("rdwr"))
nixio.dup(devnull, nixio.stdin)
nixio.dup(devnull, nixio.stdout)
nixio.dup(devnull, nixio.stderr)
return true
end