mirror of https://github.com/nocturn9x/nimd.git
112 lines
4.1 KiB
Nim
112 lines
4.1 KiB
Nim
# Copyright 2021 Mattia Giambirtone & All Contributors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import os
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import posix
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import glob
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import strutils
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import strformat
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import times
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import ../util/logging
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type ShutdownHandler* = ref object
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## A shutdown handler (internal to NimD)
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body*: proc (logger: Logger, code: int)
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proc newShutdownHandler*(body: proc (logger: Logger, code: int)): ShutdownHandler =
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result = ShutdownHandler(body: body)
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var shutdownHandlers: seq[ShutdownHandler] = @[]
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var sigTermDelay: float = 10.0
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proc addShutdownHandler*(handler: ShutdownHandler) =
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## Registers a shutdown handler to be executed
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## upon a call of NimDExit
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shutdownHandlers.add(handler)
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proc removeShutdownHandler*(handler: ShutdownHandler) =
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## Unregisters a shutdown handler
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for i, hndlr in shutdownHandlers:
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if hndlr == handler:
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shutdownHandlers.del(i)
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break
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proc anyUserlandProcessLeft: bool =
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## Returns true if there's any
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## userland processes running.
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## A userland process is one
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## whose pid is higher than 2
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## or whose /proc/<pid>/cmdline
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## file is empty. This function
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## assumes /proc is mounted and
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## readable and returns false in
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## the event of any I/O exceptions
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try:
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for dir in walkGlob("/proc/[0-9]"):
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if dir.lastPathPart.parseInt() > 2 or readFile(dir.joinPath("/cmdline")).len() == 0:
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# PID > 2 or empty cmdline file means it's a kernel process so we ignore
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# it (not that we'd have the right to send those processes a signal anyway)
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continue
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else:
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return true # There is at least one userland process running
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except OSError:
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return false
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except IOError:
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return false
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return false
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proc nimDExit*(logger: Logger, code: int, emerg: bool = true) =
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## NimD's exit point. This function tries to shut down
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## as cleanly as possible. When emerg equals true, it will
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## try to spawn a root shell and exit
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if emerg:
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var status: cint
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# We're in emergency mode: do not crash the kernel, spawn a shell and exit
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logger.fatal("NimD has entered emergency mode and cannot continue. You will be now (hopefully) dropped in a root shell: you're on your own. May the force be with you")
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logger.info("Terminating child processes with SIGKILL")
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discard posix.kill(SIGKILL, -1)
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discard posix.waitPid(-1, status, 0)
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discard execShellCmd("/bin/sh") # TODO: Is this fine? maybe use execProcess
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quit(-1)
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logger.warning("The system is shutting down")
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logger.info("Processing shutdown runlevel")
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# TODO
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logger.info("Running shutdown handlers")
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try:
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for handler in shutdownHandlers:
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handler.body(logger, code)
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except:
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logger.error(&"An error has occurred while calling shutdown handlers. Error -> {getCurrentExceptionMsg()}")
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# Note: continues calling handlers!
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logger.info("Terminating child processes with SIGTERM")
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logger.debug(&"Waiting up to {sigTermDelay} seconds for the kernel to deliver signals")
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discard posix.kill(SIGTERM, -1) # The kernel handles this for us asynchronously
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var t = cpuTime()
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# We wait some time for the signals to propagate
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while anyUserlandProcessLeft() or cpuTime() - t >= sigTermDelay:
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sleep(int(0.25 * 1000))
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if anyUserlandProcessLeft():
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logger.info("Terminating child processes with SIGKILL")
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discard posix.kill(SIGKILL, -1)
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logger.warning("Shutdown procedure complete, sending final termination signal")
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quit(code)
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