nimd/src/util/misc.nim

143 lines
5.1 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.
## Default signal handlers, exit procedures and helpers
## to allow a clean shutdown of NimD
import os
import strformat
import strutils
import syscall
import logging
# Note: This will work reliably only with absolute paths. Use with care
const symlinks: array[7, tuple[dest, source: string]] = [
(dest: "/dev/fd", source: "/proc/self/fd"),
(dest: "/dev/fd/0", source: "/proc/self/fd/0"),
(dest: "/dev/fd/1", source: "/proc/self/fd/1"),
(dest: "/dev/fd/2", source: "/proc/self/fd/2"),
(dest: "/dev/std/in", source: "/proc/self/fd/0"),
(dest: "/dev/std/out", source: "/proc/self/fd/1"),
(dest: "/dev/std/err", source: "/proc/self/fd/2"),
]
var shutdownHandlers: seq[proc (logger: Logger, code: int)] = @[]
proc doSync*(logger: Logger) =
logger.debug(&"Calling sync() syscall has returned {syscall(SYNC)}")
proc reapProcess*(logger: Logger) =
logger.debug("Handling SIGCHLD")
# TODO
proc exists*(p: string): bool =
# Checks if a path exists. Thanks
# araq :)
try:
discard getFileInfo(p)
result = true
except OSError:
result = false
proc addShutdownHandler*(handler: proc (logger: Logger, code: int), logger: Logger) =
shutdownHandlers.add(handler)
proc removeShutdownHandler*(handler: proc (logger: Logger, code: int)) =
for i, h in shutdownHandlers:
if h == handler:
shutdownHandlers.delete(i)
proc nimDExit*(logger: Logger, code: int, emerg: bool = true) =
logger.warning("The system is shutting down")
# TODO
logger.info("Processing shutdown runlevel")
# TODO
logger.info("Running shutdown handlers")
try:
for handler in shutdownHandlers:
handler(logger, code)
except:
logger.error(&"An error has occurred while calling shutdown handlers. Error -> {getCurrentExceptionMsg()}")
# Note: continues calling handlers!
if emerg:
# We're in emergency mode: do not crash the kernel, spawn a shell and exit
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")
discard execShellCmd("/bin/sh") # TODO: Is this fine? maybe use execProcess
else:
logger.info("Terminating child processes with SIGINT")
# TODO
logger.info("Terminating child processes with SIGKILL")
# TODO
logger.warning("Shutdown procedure complete, sending final termination signal")
# TODO
quit(code)
proc setHostname*(logger: Logger): string =
## Sets the machine's hostname. Returns
## the hostname that has been set or an
## empty string if an error occurs. If
## /etc/hostname doesn't exist, the hostname
## defaults to localhost
var hostname: string
try:
if not fileExists("/etc/hostname"):
logger.warning("/etc/hostname doesn't exist, defaulting to 'localhost'")
hostname = "localhost"
else:
hostname = readFile("/etc/hostname").strip(chars={'\n'})
writeFile("/proc/sys/kernel/hostname", hostname)
except:
logger.error(&"An error occurred while setting hostname -> {getCurrentExceptionMsg()}")
return ""
return hostname
proc createSymlinks*(logger: Logger) =
## Creates a set of symlinks needed
## by stuff like Linux ports of BSD
## software
for sym in symlinks:
try:
if not exists(sym.source):
logger.warning(&"Skipping creation of symbolic link from {sym.dest} to {sym.source}: destination does not exist")
continue
elif exists(sym.dest):
if symlinkExists(sym.dest) and sameFile(expandSymlink(sym.dest), sym.source):
logger.debug(&"Skipping creation of symbolic link from {sym.dest} to {sym.source}: link already exists")
elif symlinkExists(sym.dest) and not sameFile(expandSymlink(sym.dest), sym.source):
logger.warning(&"Attempted to create symbolic link from {sym.dest} to {sym.source}, but link already exists and points to {expandSymlink(sym.dest)}")
continue
logger.debug(&"Creating symbolic link from {sym.source} to {sym.dest}")
createSymlink(sym.dest, sym.source)
except:
logger.error(&"Failed to create symbolic link from {sym.dest} to {sym.source}: {getCurrentExceptionMsg()}")
proc createDirectories*(logger: Logger) =
## Creates
proc sleepSeconds*(amount: SomeInteger) = sleep(amount * 1000)
proc strsignal*(sig: cint): cstring {.header: "string.h", importc.}