libs/lucid/luasrc/lucid.lua

   1 --[[
   2 LuCI - Lua Development Framework
   3
   4 Copyright 2009 Steven Barth <steven@midlink.org>
   5
   6 Licensed under the Apache License, Version 2.0 (the "License");
   7 you may not use this file except in compliance with the License.
   8 You may obtain a copy of the License at
   9
  10 http://www.apache.org/licenses/LICENSE-2.0
  11
  12 $Id$
  13 ]]
  14
  15 local nixio = require "nixio"
  16 local table = require "table"
  17 local uci = require "luci.model.uci"
  18 local os = require "os"
  19 local io = require "io"
  20
  21 local pairs, require, pcall, assert, type = pairs, require, pcall, assert, type
  22 local ipairs, tonumber, collectgarbage = ipairs, tonumber, collectgarbage
  23
  24
  25 module "luci.lucid"
  26
  27 local slaves = {}
  28 local pollt  = {}
  29 local tickt  = {}
  30 local tpids  = {}
  31 local tcount = 0
  32 local ifaddrs = nixio.getifaddrs()
  33
  34 cursor = uci.cursor()
  35 state  = uci.cursor_state()
  36 UCINAME = "lucid"
  37
  38 local cursor = cursor
  39 local state = state
  40 local UCINAME = UCINAME
  41 local SSTATE = "/tmp/.lucid_store"
  42
  43
  44 --- Starts a new LuCId superprocess.
  45 function start()
  46         prepare()
  47
  48         local detach = cursor:get(UCINAME, "main", "daemonize")
  49         if detach == "1" then
  50                 local stat, code, msg = daemonize()
  51                 if not stat then
  52                         nixio.syslog("crit", "Unable to detach process: " .. msg .. "\n")
  53                         ox.exit(2)
  54                 end
  55         end
  56
  57         state:set(UCINAME, "main", "pid", nixio.getpid())
  58         state:save(UCINAME)
  59
  60         run()
  61 end
  62
  63 --- Stops any running LuCId superprocess.
  64 function stop()
  65         local pid = tonumber(state:get(UCINAME, "main", "pid"))
  66         if pid then
  67                 return nixio.kill(pid, nixio.const.SIGTERM)
  68         end
  69         return false
  70 end
  71
  72 --- Prepares the slaves, daemons and publishers, allocate resources.
  73 function prepare()
  74         local debug = tonumber((cursor:get(UCINAME, "main", "debug")))
  75
  76         nixio.openlog("lucid", "pid", "perror")
  77         if debug ~= 1 then
  78                 nixio.setlogmask("warning")
  79         end
  80
  81         cursor:foreach(UCINAME, "daemon", function(config)
  82                 if config.enabled ~= "1" then
  83                         return
  84                 end
  85
  86                 local key = config[".name"]
  87                 if not config.slave then
  88                         nixio.syslog("crit", "Daemon "..key.." is missing a slave\n")
  89                         os.exit(1)
  90                 else
  91                         nixio.syslog("info", "Initializing daemon " .. key)
  92                 end
  93
  94                 state:revert(UCINAME, key)
  95
  96                 local daemon, code, err = prepare_daemon(config)
  97                 if daemon then
  98                         state:set(UCINAME, key, "status", "started")
  99                         nixio.syslog("info", "Prepared daemon " .. key)
 100                 else
 101                         state:set(UCINAME, key, "status", "error")
 102                         state:set(UCINAME, key, "error", err)
 103                         nixio.syslog("err", "Failed to initialize daemon "..key..": "..
 104                         err .. "\n")
 105                 end
 106         end)
 107 end
 108
 109 --- Run the superprocess if prepared before.
 110 -- This main function of LuCId will wait for events on given file descriptors.
 111 function run()
 112         local pollint = tonumber((cursor:get(UCINAME, "main", "pollinterval")))
 113
 114         while true do
 115                 local stat, code = nixio.poll(pollt, pollint)
 116
 117                 if stat and stat > 0 then
 118                         for _, polle in ipairs(pollt) do
 119                                 if polle.revents ~= 0 and polle.handler then
 120                                         polle.handler(polle)
 121                                 end
 122                         end
 123                 elseif stat == 0 then
 124                         ifaddrs = nixio.getifaddrs()
 125                         collectgarbage("collect")
 126                 end
 127
 128                 for _, cb in ipairs(tickt) do
 129                         cb()
 130                 end
 131
 132                 local pid, stat, code = nixio.wait(-1, "nohang")
 133                 while pid and pid > 0 do
 134                         tcount = tcount - 1
 135                         if tpids[pid] and tpids[pid] ~= true then
 136                                 tpids[pid](pid, stat, code)
 137                         end
 138                         pid, stat, code = nixio.wait(-1, "nohang")
 139                 end
 140         end
 141 end
 142
 143 --- Add a file descriptor for the main loop and associate handler functions.
 144 -- @param polle Table containing: {fd = FILE DESCRIPTOR, events = POLL EVENTS,
 145 -- handler = EVENT HANDLER CALLBACK}
 146 -- @see unregister_pollfd
 147 -- @return boolean status
 148 function register_pollfd(polle)
 149         pollt[#pollt+1] = polle
 150         return true
 151 end
 152
 153 --- Unregister a file desciptor and associate handler from the main loop.
 154 -- @param polle Poll descriptor
 155 -- @see register_pollfd
 156 -- @return boolean status
 157 function unregister_pollfd(polle)
 158         for k, v in ipairs(pollt) do
 159                 if v == polle then
 160                         table.remove(pollt, k)
 161                         return true
 162                 end
 163         end
 164         return false
 165 end
 166
 167 --- Close all registered file descriptors from main loop.
 168 -- This is useful for forked child processes.
 169 function close_pollfds()
 170         for k, v in ipairs(pollt) do
 171                 if v.fd and v.fd.close then
 172                         v.fd:close()
 173                 end
 174         end
 175 end
 176
 177 --- Register a tick function that will be called at each cycle of the main loop.
 178 -- @param cb Callback
 179 -- @see unregister_tick
 180 -- @return boolean status
 181 function register_tick(cb)
 182         tickt[#tickt+1] = cb
 183         return true
 184 end
 185
 186 --- Unregister a tick function from the main loop.
 187 -- @param cb Callback
 188 -- @see register_tick
 189 -- @return boolean status
 190 function unregister_tick(cb)
 191         for k, v in ipairs(tickt) do
 192                 if v == cb then
 193                         table.remove(tickt, k)
 194                         return true
 195                 end
 196         end
 197         return false
 198 end
 199
 200 --- Create a new child process from a Lua function and assign a destructor.
 201 -- @param threadcb main function of the new process
 202 -- @param waitcb destructor callback
 203 -- @return process identifier or nil, error code, error message
 204 function create_process(threadcb, waitcb)
 205         local threadlimit = tonumber(cursor:get(UCINAME, "main", "threadlimit"))
 206         if threadlimit and tcount >= threadlimit then
 207                 nixio.syslog("warning", "Cannot create thread: process limit reached")
 208                 return nil
 209         end
 210         local pid, code, err = nixio.fork()
 211         if pid and pid ~= 0 then
 212                 tpids[pid] = waitcb
 213                 tcount = tcount + 1
 214         elseif pid == 0 then
 215                 local code = threadcb()
 216                 os.exit(code)
 217         else
 218                 nixio.syslog("err", "Unable to fork(): " .. err)
 219         end
 220         return pid, code, err
 221 end
 222
 223 --- Prepare a daemon from a given configuration table.
 224 -- @param config Configuration data.
 225 -- @return boolean status or nil, error code, error message
 226 function prepare_daemon(config)
 227         nixio.syslog("info", "Preparing daemon " .. config[".name"])
 228         local modname = cursor:get(UCINAME, config.slave)
 229         if not modname then
 230                 return nil, -1, "invalid slave"
 231         end
 232
 233         local stat, module = pcall(require, _NAME .. "." .. modname)
 234         if not stat or not module.prepare_daemon then
 235                 return nil, -2, "slave type not supported"
 236         end
 237
 238         config.slave = prepare_slave(config.slave)
 239
 240         return module.prepare_daemon(config, _M)
 241 end
 242
 243 --- Prepare a slave.
 244 -- @param name slave name
 245 -- @return table containing slave module and configuration or nil, error message
 246 function prepare_slave(name)
 247         local slave = slaves[name]
 248         if not slave then
 249                 local config = cursor:get_all(UCINAME, name)
 250
 251                 local stat, module = pcall(require, config and config.entrypoint)
 252                 if stat then
 253                         slave = {module = module, config = config}
 254                 end
 255         end
 256
 257         if slave then
 258                 return slave
 259         else
 260                 return nil, module
 261         end
 262 end
 263
 264 --- Return a list of available network interfaces on the host.
 265 -- @return table returned by nixio.getifaddrs()
 266 function get_interfaces()
 267         return ifaddrs
 268 end
 269
 270 --- Revoke process privileges.
 271 -- @param user new user name or uid
 272 -- @param group new group name or gid
 273 -- @return boolean status or nil, error code, error message
 274 function revoke_privileges(user, group)
 275         if nixio.getuid() == 0 then
 276                 return nixio.setgid(group) and nixio.setuid(user)
 277         end
 278 end
 279
 280 --- Return a secure UCI cursor.
 281 -- @return UCI cursor
 282 function securestate()
 283         local stat = nixio.fs.stat(SSTATE) or {}
 284         local uid = nixio.getuid()
 285         if stat.type ~= "dir" or (stat.modedec % 100) ~= 0 or stat.uid ~= uid then
 286                 nixio.fs.remover(SSTATE)
 287                 if not nixio.fs.mkdir(SSTATE, 700) then
 288                         local errno = nixio.errno()
 289                         nixio.syslog("err", "Integrity check on secure state failed!")
 290                         return nil, errno, nixio.perror(errno)
 291                 end
 292         end
 293
 294         return uci.cursor(nil, SSTATE)
 295 end
 296
 297 --- Daemonize the process.
 298 -- @return boolean status or nil, error code, error message
 299 function daemonize()
 300         if nixio.getppid() == 1 then
 301                 return
 302         end
 303
 304         local pid, code, msg = nixio.fork()
 305         if not pid then
 306                 return nil, code, msg
 307         elseif pid > 0 then
 308                 os.exit(0)
 309         end
 310
 311         nixio.setsid()
 312         nixio.chdir("/")
 313
 314         local devnull = nixio.open("/dev/null", nixio.open_flags("rdwr"))
 315         nixio.dup(devnull, nixio.stdin)
 316         nixio.dup(devnull, nixio.stdout)
 317         nixio.dup(devnull, nixio.stderr)
 318
 319         return true
 320 end