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Я играю с модулем luaposix (используя luajit), пытаясь узнать, как разветвлять процесс и демонизировать его. Вот код, который создает новый процесс и пытается настроить очередь сообщений для связи с дочерним процессом. Я использую функцию msgget (ключ) для создания очереди, но функция выдает ошибку «Нет такого файла или каталога», пожалуйста, может кто-нибудь помочь мне понять, в чем ошибка?

 local psx = require("posix");
local os = require("os");

--daemon sleep before die
local DAEMON_SLEEP_BD = 20;
--sleep seconds in write
local SLEEP_SEC = 1;
--message que key
local MSGQ_KEY = 1000;


function main()
  local ppid = nil;
  local pid = nil;
  local sid = nil;

  --clear screen
  os.execute("clear");

  --get process pid - this is the parent
  ppid = psx.getpid ("pid"); 

  psx.sleep(SLEEP_SEC);
  io.write("proces started with pid : "..ppid.."n");
  psx.sleep(SLEEP_SEC);

  --create a msq queque
  psx.sleep(SLEEP_SEC);
  io.write("process "..ppid.." is going to create a msg queue...n");
  psx.sleep(SLEEP_SEC);

  local msgqid = psx.msgget(MSGQ_KEY,psx.IPC_CREATE);

  if msgqid==nil then
    psx.sleep(SLEEP_SEC);
    io.write(psx.errno().."n");
    io.write("process "..ppid.." failed to create msg queue...stopping executionn") ;
    psx.sleep(SLEEP_SEC); 

    psx._exit(-1);
  end

  psx.sleep(SLEEP_SEC); 
  io.write("process "..ppid.." created msg que with identifier "..msgqid.."n");
  psx.sleep(SLEEP_SEC); 

  psx.sleep(SLEEP_SEC);
  io.write("process "..ppid.." is going to forkn");
  psx.sleep(SLEEP_SEC);

  pid = psx.fork(); 

  if pid < 0 then
    psx.sleep(SLEEP_SEC);
    io.write("process " ..ppid.." failed to fork...stopping executionn")
    psx.sleep(SLEEP_SEC);

    psx._exit(-1);
  end

  if pid > 0 then
    --##################################################
    --here put the code of parent process after the fork
    --##################################################

    psx.sleep(SLEEP_SEC);
    io.write("process "..ppid.." is going to wait msg from forked childn");
    psx.sleep(SLEEP_SEC);

    while true do
      psx.sleep(SLEEP_SEC);
      io.write("process "..ppid.." waiting for msg from forked process.n");
      psx.sleep(SLEEP_SEC);

      local msg_type, msg_text = psx.msgrcv(msgqid,1,100)

      if msg_type == nil then 
        psx.sleep(SLEEP_SEC);
        io.write("process " ..ppid.." raised error receiving msg...stopping executionn");
        psx.sleep(SLEEP_SEC);

        psx._exit(-1);
      end

      if msg_text == "ok" then
        psx.sleep(SLEEP_SEC);
        io.write("process "..ppid.." received mesg from forked "..msg_text.." stopping execution to demonazen");
        psx.sleep(SLEEP_SEC);

        psx.sleep(SLEEP_SEC);
        io.write("process "..ppid.." die letting fork to demonizen");
        psx.sleep(SLEEP_SEC);

        psx._exit(0);
      end

    end --while  

  end --if

  --#################################################################
  --here write the code of child process that will setup it as daemon
  --#################################################################

  pid = psx.getpid("pid");

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." born from fork is the candidate daemon...n");
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write(str.format("process "..pid.." eredited db env %s n",envv));
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write(str.format("process "..pid.." eredited db connection %s n",con));
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." changing umaskn");
  psx.sleep(SLEEP_SEC);

  psx.umask(0);

  --open log for writing --to_do

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." changing setsid...n");
  psx.sleep(SLEEP_SEC);

  sid = psx.setpid("s");

  if sid ==nill then
    psx.sleep(SLEEP_SEC);
    io.write("process "..pid.." setsid failedn");
    psx.sleep(SLEEP_SEC);

    psx._exit(-1);
  end

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." candidate daemon sid :"..sid.."n");  
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." changing working directory.n");
  psx.sleep(SLEEP_SEC);

  if psx.chdir("/")==nill then
    psx.sleep(SLEEP_SEC);
    io.write(".....can't change the dirn");
    psx.sleep(SLEEP_SEC);

    psx._exit(-1);
  end

  psx.sleep(SLEEP_SEC);
  io.write("process " ..pid.." changed directory to "..psx.getcwd().."n");
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." attaching parent message queue with msgq_key "..MSGQ_KEY.."n");
  psx.sleep(SLEEP_SEC);

  --attach the msg que using the same key
  msgqid = psx.msgget(MSGQ_KEY); 
  if msgqid == nill then
    psx.sleep(SLEEP_SEC);
    io.write("process "..pid.." attaching msgq failed...stopping executionn");
    psx.sleep(SLEEP_SEC);

    psx._exit(-1);
  end

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." has attached msq queue with msgid "..msgqid.."n");
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." going to close all file descriptor now is a daemonn");
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." entering in while loop.n");
  psx.sleep(SLEEP_SEC);

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." sending msg to parent telling him to dien");
  psx.sleep(SLEEP_SEC);

  if psx.msgsnd(msgqid,1,"ok")==nil then
    psx.sleep(SLEEP_SEC);
    io.write("process "..pid.." raised error sending msg...stopping execution.n");
    psx.sleep(SLEEP_SEC);
  end

  psx.sleep(SLEEP_SEC);
  io.write("process "..pid.." msg sentn");
  psx.sleep(SLEEP_SEC);



  psx.close(0);
  psx.close(1);
  psx.close(2);

  while true do
    --here write the code of daemon
    --you can't use io.write/print because fd are closed

    psx.sleep(DAEMON_SLEEP_BD)
    psx._exit(0); 

  end --while



end --main

main()