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10176 :: How can I create a process completely detached of my process?

• xTrayambak (orginal) [2023-05-06T13:44:26+02:00] view original

  Hello everyone, so recently I've tried to make a program that spawns another process, and I use os.execCmd for this. It works, but the problem is that if the child process is killed, the parent dies too. Is there any way to detach this child from the parent process? Thanks, and I'm sorry if any details are lacking here.

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• archnim (orginal) [2023-05-06T15:39:04+02:00] view original

  Is there any code after the execCmd that is not executed ?? If not, then it's normal for the parent to die after the child is killed. (Are we on a hitman forum ? 😄 😁)

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• jackhftang (orginal) [2023-05-06T16:01:07+02:00] view original

  That is called fork.

  https://nim-lang.org/docs/posix.html#fork

  https://man7.org/linux/man-pages/man2/fork.2.html

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• xTrayambak (orginal) [2023-05-07T06:53:47+02:00] view original

  Yes, @archnim, code is executed after the child process dies out.

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• archnim (orginal) [2023-05-08T02:49:00+02:00] view original

  Can you post a minimal code with the bug in it ?

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• xTrayambak (orginal) [2023-05-08T09:23:07+02:00] view original

  Yes.

  
  import chronicles, ../../rand, osproc, strformat,
         ../../ipc/server,
         ../../sandbox/processtypes
  
  # The higher the number, more the time taken to generate the string,
  # but lesser the chance for a Broker signature conflict causing major confusions
  # TODO: Put an end to Broker conflicts, make sure they never share the same signature.
  const FERUS_BROKER_ALPHABET_SEQUENCE_LENGTH = 128
  
  type Broker* = ref object of RootObj
    ipcServer*: IPCServer
    signature*: string
  
  proc createNewProcess*(broker: Broker, procType: ProcessType) =
    info "[src/sandbox/linux/broker.nim] Broker is creating new process!"
    
    discard execCmd("./libferuscli" & fmt" --role={processTypeToString(procType)} --broker-affinity-signature={broker.signature}")
  
  proc newBroker*(ipcServer: IPCServer): Broker =
    var hasherInput = getRandAlphabetSequence(FERUS_BROKER_ALPHABET_SEQUENCE_LENGTH)
    info "[src/sandbox/linux/broker.nim] New broker initializing!", hasherInput=hasherInput
    Broker(ipcServer: ipcServer, signature: hasherInput)
  Run

  Everything here can be ignored, the only thing that's important is createNewProcess(). I don't want the process running this to be frozen whilst the child runs, as the child will run for as long as the app should run, and it's also going to run using a seperate binary I package alongside my app. I want to do stuff in my main process as the child is doing its work. I don't think fork() can run another binary.

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