https://github.com/spcomb/netdaemon

[Archive] Prototype container init / service manager daemon (2009)
https://github.com/spcomb/netdaemon

Last synced: 10 months ago
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[Archive] Prototype container init / service manager daemon (2009)

• Host: GitHub
• URL: https://github.com/spcomb/netdaemon
• Owner: SpComb
• Created: 2017-10-25T09:29:28.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-10-25T09:40:33.000Z (over 8 years ago)
• Last Synced: 2025-08-05T05:56:21.459Z (10 months ago)
• Language: C
• Size: 388 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README

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README

          
*** netdaemon ***

Remote control of persistent processes.

** About *

netdaemon is a daemon program that offers an remote/asynchronous API for running and controlling a set of other

processes. Also included is a client library and command-line utility.

The daemon runs a set of background processes, and clients may connect to the daemon (over an UNIX socket) and attach

to a process to control it. Clients can also query the list of available processes and start new ones. The daemon

offers control over:

    * exec path

    * exec arguments

    * exec environment

    * sending signals

    * watching status (exit, kill)

    * sending data/EOF to stdin

    * recieving data/EOF from stdout/stderr

** Operation **

Each connection to the daemon undergoes protocol handshake before proceeding to actual operation.

In operational mode, the client can:

    * query the listing of active processes (CMD_LIST)

    * attach to a running process (CMD_ATTACH)

    * perform operations on the attached process and recieve operational status

        * recieve notification of exit/signal-terminate (CMD_STATUS)

        * send data/eof to stdin (CMD_DATA)

        * recieve data/eof from stdout/stderr (CMD_DATA)

        * send signals (CMD_KILL)

    * start a new process and attach to it (CMD_START)

Each client connection can, at most, be attached to one process at a time.

Each process initiated has an unique ID handle associated with it, which can be used by the clients to identify and

attach to a process after starting one and reconnecting.

** Compiling **

The code has been developed on Ubuntu Linux 2.6.24/28 using GCC 4.2.4/4.3.3.

It uses GNU-specific extensions to the C language, and hence compiles with -std=gnu99 and uses _GNU_SOURCE in places.

The code compiles without warnings apart from passing non-void* to printf-%p.

    

    make

** Examples **

    0$ ./bin/daemon -v -u run/netdaemon

    1$ ./bin/client -q -u run/netdaemon start -- /usr/bin/wc -l

        foo

        bar

        ^C 

        

    1$ ./bin/client -u run/netdaemon list

      > ... process_id=/usr/bin/wc:31299, status=1:31299

    1$ ./bin/client -u run/netdaemon attach /usr/bin/wc:31299

        ^D

      > 2

    1$ ./bin/client -u run/netdaemon start -- /bin/cat

      > ... Attached to process: /bin/cat:31464

        foo

      > foo

    2$ ./bin/client -u run/netdaemon kill /bin/cat:31464 15

    

    1$

      > Terminated

** Bugs **

Sometimes, the client will disconnect as soon as the process exits, but before it recieves all stdout/err output.

** TODO **

    * proto:    also transmit stdin/out/err EOF-state in CMD_ATTACHED/CMD_STATUS, so the client doesn't try and feed

                input to a closed stdin

           

    * daemon:   resolve behaviour of select_loop_del as regards calling from within select_loop_run

    * client:   ordering of on_exit/on_stdout/stderr-eof to only exit once process has exited AND we have EOF on both

    

    * client:   better display of process status