nimd/src/main.nim

183 lines
8.7 KiB
Nim

# Copyright 2021 Mattia Giambirtone & All Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import parseopt
import strformat
import posix
import os
# NimD's own stuff
import util/[logging, constants, misc, config]
import core/[mainloop, fs, shutdown, services]
proc addStuff =
## Adds stuff to test NimD. This is
## a temporary procedure
# Adds symlinks
addSymlink(newSymlink(dest="/dev/fd", source="/proc/self/fd"))
addSymlink(newSymlink(dest="/dev/fd/0", source="/proc/self/fd/0"))
addSymlink(newSymlink(dest="/dev/fd/1", source="/proc/self/fd/1"))
addSymlink(newSymlink(dest="/dev/fd/2", source="/proc/self/fd/2"))
addSymlink(newSymlink(dest="/dev/std/in", source="/proc/self/fd/0"))
addSymlink(newSymlink(dest="/dev/std/out", source="/proc/self/fd/1"))
addSymlink(newSymlink(dest="/dev/std/err", source="/proc/self/fd/2"))
# Tests here. Check logging output (debug) to see if
# they work as intended
addSymlink(newSymlink(dest="/dev/std/err", source="/")) # Should say link already exists and points to /proc/self/fd/2
addSymlink(newSymlink(dest="/dev/std/in", source="/does/not/exist")) # Should say destination does not exist
addSymlink(newSymlink(dest="/dev/std/in", source="/proc/self/fd/0")) # Should say link already exists
addDirectory(newDirectory("test", 764)) # Should create a directory
addDirectory(newDirectory("/dev/disk", 123)) # Should say directory already exists
# Adds test services
var echoer = newService(name="echoer", description="prints owo", exec="/bin/echo owoooooooooo",
runlevel=Boot, kind=Simple, workDir=getCurrentDir(),
supervised=false, restart=Always, restartDelay=5,
depends=(@[]), provides=(@[]))
var errorer = newService(name="errorer", description="la mamma di gavd",
exec="/bin/false", supervised=true, restart=OnFailure,
restartDelay=5, runlevel=Boot, workDir="/", kind=Simple,
depends=(@[]), provides=(@[]))
var exiter = newService(name="exiter", description="la mamma di licenziat",
exec="/bin/true", supervised=true, restart=Always,
restartDelay=5, runlevel=Boot, workDir="/", kind=Simple,
depends=(@[newDependency(Other, errorer)]), provides=(@[]))
var shell = newService(name="login", description="A simple login shell", kind=Simple,
getCurrentDir(), runlevel=Default, exec="/bin/login -f root",
supervised=true, restart=Always, restartDelay=5, depends=(@[]), provides=(@[]),
useParentStreams=true
)
addService(errorer)
addService(echoer)
addService(exiter)
addService(shell)
proc main(logger: Logger, config: NimDConfig) =
## NimD's entry point and setup
## function
logger.debug(&"Setting log file to '{config.logFile}'")
setLogFile(file=config.logFile)
logger.debug("Starting NimD: A minimal, self-contained, dependency-based Linux init system written in Nim")
logger.info(&"NimD version {NimdVersion.major}.{NimdVersion.minor}.{NimdVersion.patch} is starting up!")
logger.trace("Calling getCurrentProcessId()")
let pid = getCurrentProcessId()
logger.trace(&"getCurrentProcessId() returned {pid}")
if pid != 1:
logger.warning(&"Expecting to run as PID 1, but current process ID is {pid}")
logger.trace("Calling getuid()")
let uid = posix.getuid()
logger.trace(&"getuid() returned {uid}")
if uid != 0:
logger.fatal(&"NimD must run as root, but current user id is {uid}")
nimDExit(logger, EPERM, emerg=false) # EPERM - Operation not permitted
logger.trace("Setting up signal handlers")
onSignal(SIGABRT, SIGALRM, SIGHUP, SIGILL, SIGKILL, SIGQUIT, SIGSTOP, SIGSEGV, SIGTSTP,
SIGTRAP, SIGPIPE, SIGUSR1, SIGUSR2, 6, SIGFPE, SIGBUS, SIGURG, SIGTERM, SIGINT): # 6 is SIGIOT
# Can't capture local variables because this implicitly generates
# a noconv procedure, so we use getDefaultLogger() instead
getDefaultLogger().warning(&"Ignoring signal {sig} ({strsignal(sig)})") # Nim injects the variable "sig" into the scope. Gotta love those macros
onSignal(SIGCHLD):
# One of the key features of an init system is reaping child
# processes!
reapProcess(getDefaultLogger())
if config.autoUnmount:
logger.debug("Setting up shutdown handler for automatic disk unmounting")
# Shutdown handler to unmount disks
addShutdownHandler(newShutdownHandler(unmountAllDisks))
addStuff()
try:
if config.autoMount:
logger.info("Mounting filesystem")
mountDisks(logger, config.fstab)
else:
logger.info("Skipping disk mounting, assuming this has already been done")
logger.info("Creating symlinks")
createSymlinks(logger)
logger.info("Creating directories")
createDirectories(logger)
logger.info("Filesystem preparation complete")
logger.debug("Calling sync() just in case")
doSync(logger)
except:
logger.fatal(&"A fatal error has occurred while preparing filesystem, booting cannot continue. Error -> {getCurrentExceptionMsg()}")
nimDExit(logger, 131, emerg=false)
if config.setHostname:
logger.info("Setting hostname")
logger.debug(&"Hostname was set to '{misc.setHostname(logger)}'")
else:
logger.info("Skipping setting hostname")
logger.debug("Entering critical fork() section: blocking signals")
blockSignals(logger) # They are later unblocked in mainLoop
logger.info("Processing boot runlevel")
startServices(logger, workers=config.workers, level=Boot)
logger.debug("Starting main loop")
mainLoop(logger, config)
when isMainModule:
var logger = getDefaultLogger()
var optParser = initOptParser(commandLineParams())
for kind, key, value in optParser.getopt():
case kind:
of cmdArgument:
echo "Error: unexpected argument"
quit(EINVAL)
of cmdLongOption:
case key:
of "help":
echo helpMessage
quit(0)
of "version":
echo NimDVersionString
quit(0)
of "verbose":
logger.setLevel(LogLevel.Debug)
of "extra":
logger.setLevel(LogLevel.Trace)
else:
echo &"Unkown command-line long option '{key}'"
quit(EINVAL) # EINVAL - Invalid argument
of cmdShortOption:
case key:
of "h":
echo helpMessage
quit(0)
of "v":
echo NimDVersionString
quit(0)
of "V":
logger.setLevel(LogLevel.Debug)
of "X":
logger.setLevel(LogLevel.Trace)
else:
echo &"Unkown command-line short option '{key}'"
echo "Usage: nimd [options]"
echo "Try nimd --help for more info"
quit(EINVAL) # EINVAL - Invalid argument
else:
echo "Usage: nimd [options]"
quit(EINVAL) # EINVAL - Invalid argument
setStdIoUnbuffered() # Colors don't work otherwise!
try:
main(logger, parseConfig(logger, "/etc/nimd/nimd.conf"))
except:
logger.fatal(&"A fatal unrecoverable error has occurred during startup and NimD cannot continue: {getCurrentExceptionMsg()}")
nimDExit(logger, 131) # ENOTRECOVERABLE - State not recoverable
# This will almost certainly cause the kernel to crash with an error the likes of "Kernel not syncing, attempted to kill init!",
# but, after all, there isn't much we can do if we can't even initialize *ourselves* is there?