mirror of https://github.com/nocturn9x/nimd.git
226 lines
13 KiB
Nim
226 lines
13 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 strutils
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import sequtils
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import strformat
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import posix
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import os
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import logging
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import misc
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const virtualFileSystems: array[6, tuple[source: string, target: string, filesystemtype: string, mountflags: uint64, data: string, dump, pass: uint8]] = [
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# ALl the standard POSIX filesystems needed by the OS to work properly are listed here
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(source: "proc", target: "/proc", filesystemtype: "proc", mountflags: 0u64, data: "nosuid,noexec,nodev", dump: 0u8, pass: 0u8),
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(source: "sys", target: "/sys", filesystemtype: "sysfs", mountflags: 0u64, data: "nosuid,noexec,nodev", dump: 0u8, pass: 0u8),
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(source: "run", target: "/run", filesystemtype: "tmpfs", mountflags: 0u64, data: "mode=0755,nosuid,nodev", dump: 0u8, pass: 0u8),
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(source: "dev", target: "/dev", filesystemtype: "devtmpfs", mountflags: 0u64, data: "mode=0755,nosuid", dump: 0u8, pass: 0u8),
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(source: "devpts", target: "/dev/pts", filesystemtype: "devpts", mountflags: 0u64, data: "mode=0620,gid=5,nosuid,noexec", dump: 0u8, pass: 0u8),
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(source: "shm", target: "/dev/shm", filesystemtype: "tmpfs", mountflags: 0u64, data: "mode=1777,nosuid,nodev", dump: 0u8, pass: 0u8),
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]
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proc parseFileSystemTable*(fstab: string): seq[tuple[source, target, filesystemtype: string, mountflags: uint64, data: string, dump, pass: uint8]] =
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## Parses the contents of the given file (the contents of /etc/fstab or /etc/mtab
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## most of the time, but this is not enforced in any way) and returns a sequence
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## of tuples with elements source, target, filesystemtype, mountflags, data, dump
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## and pass as required by mount/umount/umount2 in sys/mount.h which are wrapped below.
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## The types of these arguments are Nim types to make the garbage collector happy
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## and avoid freeing the underlying string object.
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## An improperly formatted fstab will cause this function to error out with a
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## ValueError exception (when an entry is incomplete) that should be caught by
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## the caller. No other checks other than very basic syntax are performed, as
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## that job is delegated to the operating system. Missing dump/pass entries are
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## interpreted as if they were set to 0, following the way Linux does it.
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## Note that this function automatically converts UUID/LABEL/PARTUUID/ID directives
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## to their corresponding /dev/disk symlink just like the mount command would do
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## on a Linux system.
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var temp: seq[string] = @[]
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var dump: int
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var pass: int
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var line: string = ""
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for l in fstab.splitlines():
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line = l.strip().replace("\t", " ")
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if line.startswith("#") or line.isEmptyOrWhitespace():
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continue
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# This madness will make sure we only get (hopefully) 6 entries
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# in our temporary list
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temp = line.split().filterIt(it != "").join(" ").split(maxsplit=6)
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if len(temp) < 6:
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if len(temp) < 4:
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# Not enough columns!
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raise newException(ValueError, "improperly formatted filesystem table")
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elif len(temp) == 4:
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dump = 0
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pass = 0
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elif len(temp) == 5:
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dump = 0
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else:
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try:
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dump = parseInt(temp[4])
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except ValueError:
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raise newException(ValueError, &"improperly formatted filesystem table -> invalid value ({dump}) for dump")
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try:
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pass = parseInt(temp[5])
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except ValueError:
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raise newException(ValueError, &"improperly formatted filesystem table -> invalid value ({pass}) for pass")
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if dump notin 0..1:
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raise newException(ValueError, &"invalid value in filesystem table -> invalid value ({dump}) for dump")
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if pass notin 0..2:
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raise newException(ValueError, &"invalid value in filesystem table -> invalid value ({pass}) for pass")
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if temp[0].toLowerAscii().startswith("id="):
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if (let s = temp[0].split("=", maxsplit=2); len(s) < 2):
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raise newException(ValueError, "improperly formatted filesystem table")
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temp[0] = &"""/dev/disk/by-id/{temp[0].split("=", maxsplit=2)[1]}"""
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if temp[0].toLowerAscii().startswith("label="):
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if (let s = temp[0].split("=", maxsplit=2); len(s) < 2):
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raise newException(ValueError, "improperly formatted filesystem table")
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temp[0] = &"""/dev/disk/by-label/{temp[0].split("=", maxsplit=2)[1]}"""
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if temp[0].toLowerAscii().startswith("uuid="):
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if (let s = temp[0].split("=", maxsplit=2); len(s) < 2):
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raise newException(ValueError, "improperly formatted filesystem table")
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temp[0] = &"""/dev/disk/by-uuid/{temp[0].split("=", maxsplit=2)[1]}"""
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if temp[0].toLowerAscii().startswith("partuuid="):
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if (let s = temp[0].split("=", maxsplit=2); len(s) < 2):
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raise newException(ValueError, "improperly formatted filesystem table")
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temp[0] = &"""/dev/disk/by-partuuid/{temp[0].split("=", maxsplit=2)[1]}"""
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result.add((source: temp[0], target: temp[1], filesystemtype: temp[2], mountflags: 0u64, data: temp[3], dump: uint8(dump), pass: uint8(pass)))
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# Nim wrappers around C functionality in sys/mount.h on Linux
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proc mount*(source: cstring, target: cstring, filesystemtype: cstring,
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mountflags: culong, data: pointer): cint {.header: "sys/mount.h", importc.}
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# Since cstrings are weak references, we need to convert nim strings to cstrings only
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# when we're ready to use them and only when we're sure the underlying nim string is
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# in scope, otherwise garbage collection madness happens
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proc mount*(source, target, filesystemtype: string, mountflags: uint64, data: string): int = int(mount(cstring(source), cstring(target), cstring(filesystemtype), culong(mountflags), cstring(data)))
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proc umount*(target: cstring): cint {.header: "sys/mount.h", importc.}
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proc umount2*(target: cstring, flags: cint): cint {.header: "sys/mount.h", importc.}
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# These 2 wrappers silent the CStringConv warning
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# (implicit conversion to 'cstring' from a non-const location)
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proc umount*(target: string): int = int(umount(cstring(target)))
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proc umount2*(target: string, flags: int): int = int(umount2(cstring(target), cint(flags)))
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proc exists(p: string): bool =
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# Checks if a path exists. Thanks
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# araq :)
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try:
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discard getFileInfo(p)
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result = true
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except OSError:
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result = false
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proc checkDisksIsMounted(search: tuple[source, target, filesystemtype: string, mountflags: uint64, data: string, dump, pass: uint8], expand: bool = false): bool =
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## Returns true if a disk is already mounted. If expand is true,
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## symlinks are expanded and checked instead of doing a simple
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## string comparison of the source entry point. This should be
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## true when mounting real filesystems. This returns false if
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## /proc/mounts does not exist (usually happens when /proc has
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## not been mounted yet)
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if not fileExists("/proc/mounts"):
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return false
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for entry in parseFileSystemTable(readFile("/proc/mounts")):
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if expand:
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if exists(entry.source) and exists(search.source) and sameFile(entry.source, search.source):
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return true
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elif entry.source == search.source:
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return true
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return false
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proc mountRealDisks*(logger: Logger, fstab: string = "/etc/fstab") =
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## Mounts real disks from /etc/fstab
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var retcode = 0
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try:
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logger.debug(&"Reading disk entries from {fstab}")
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for entry in parseFileSystemTable(readFile(fstab)):
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if checkDisksIsMounted(entry, expand=true):
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logger.debug(&"Skipping mounting filesystem {entry.source} ({entry.filesystemtype}) at {entry.target}: already mounted")
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continue
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logger.debug(&"Mounting filesystem {entry.source} ({entry.filesystemtype}) at {entry.target} with mount option(s) {entry.data}")
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logger.trace(&"Calling mount('{entry.source}', '{entry.target}', '{entry.filesystemtype}', {entry.mountflags}, '{entry.data}')")
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retcode = mount(entry.source, entry.target, entry.filesystemtype, entry.mountflags, entry.data)
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logger.trace(&"mount('{entry.source}', '{entry.target}', '{entry.filesystemtype}', {entry.mountflags}, '{entry.data}') returned {retcode}")
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if retcode == -1:
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logger.error(&"Mounting {entry.source} at {entry.target} has failed with error {posix.errno}: {posix.strerror(posix.errno)}")
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# Resets the error code
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posix.errno = cint(0)
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else:
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logger.debug(&"Mounted {entry.source} at {entry.target}")
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except ValueError: # Check parseFileSystemTable for more info on this catch block
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logger.fatal("Improperly formatted fstab, exiting")
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nimDExit(logger, 131)
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proc mountVirtualDisks*(logger: Logger) =
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## Mounts POSIX virtual filesystems/partitions,
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## such as /proc and /sys
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var retcode = 0
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for entry in virtualFileSystems:
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if checkDisksIsMounted(entry):
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logger.debug(&"Skipping mounting filesystem {entry.source} ({entry.filesystemtype}) at {entry.target}: already mounted")
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continue
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logger.debug(&"Mounting filesystem {entry.source} ({entry.filesystemtype}) at {entry.target} with mount option(s) {entry.data}")
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logger.trace(&"Calling mount('{entry.source}', '{entry.target}', '{entry.filesystemtype}', {entry.mountflags}, '{entry.data}')")
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retcode = mount(entry.source, entry.target, entry.filesystemtype, entry.mountflags, entry.data)
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logger.trace(&"mount('{entry.source}', '{entry.target}', '{entry.filesystemtype}', {entry.mountflags}, '{entry.data}') returned {retcode}")
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if retcode == -1:
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logger.error(&"Mounting disk {entry.source} at {entry.target} has failed with error {posix.errno}: {posix.strerror(posix.errno)}")
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# Resets the error code
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posix.errno = cint(0)
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logger.fatal("Failed mounting vital system disk partition, system is likely corrupted, booting cannot continue")
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nimDExit(logger, 131) # ENOTRECOVERABLE - State not recoverable
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else:
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logger.debug(&"Mounted {entry.source} at {entry.target}")
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proc unmountAllDisks*(logger: Logger, code: int) =
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## Unmounts all currently mounted disks, including the ones that
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## were not mounted trough fstab but excluding virtual filesystems
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var flag: bool = false
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var retcode = 0
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try:
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logger.info("Detaching real filesystems")
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logger.debug(&"Reading disk entries from /proc/mounts")
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for entry in parseFileSystemTable(readFile("/proc/mounts")):
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if entry.source in ["proc", "sys", "run", "dev", "devpts", "shm"]:
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flag = true # We don't detach the vfs
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for path in ["/proc", "/sys", "/run", "/dev", "/dev/pts", "/dev/shm"]:
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if entry.target.startswith(path):
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flag = true
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if flag:
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flag = false
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logger.debug(&"Skipping unmounting filesystem {entry.source} ({entry.filesystemtype}) from {entry.target} as it is a virtual filesystem")
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continue
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if not checkDisksIsMounted(entry):
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logger.debug(&"Skipping unmounting filesystem {entry.source} ({entry.filesystemtype}) from {entry.target}: not mounted")
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continue
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logger.debug(&"Unmounting filesystem {entry.source} ({entry.filesystemtype}) from {entry.target}")
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logger.trace(&"Calling umount2('{entry.target}', MNT_DETACH)")
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retcode = umount2(entry.target, 2) # 2 = MNT_DETACH - Since we're shutting down, we need the disks to be *gone*!
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logger.trace(&"umount2('{entry.target}', MNT_DETACH) returned {retcode}")
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if retcode == -1:
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logger.error(&"Unmounting disk {entry.source} from {entry.target} has failed with error {posix.errno}: {posix.strerror(posix.errno)}")
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# Resets the error code
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posix.errno = cint(0)
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else:
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logger.debug(&"Unmounted {entry.source} from {entry.target}")
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except ValueError: # Check parseFileSystemTable for more info on this catch block
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logger.fatal(&"A fatal error occurred while unmounting disks: {getCurrentExceptionMsg()}")
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nimDExit(logger, 131)
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