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Filename : udev
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#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          udev
# Required-Start:    mountkernfs
# Required-Stop:     umountroot
# Default-Start:     S
# Default-Stop:      0 6
# Short-Description: Start systemd-udevd, populate /dev and load drivers.
### END INIT INFO

PATH="/sbin:/bin"
NAME="systemd-udevd"
DAEMON="/lib/systemd/systemd-udevd"
DESC="hotplug events dispatcher"
PIDFILE="/run/udev.pid"
CTRLFILE="/run/udev/control"
OMITDIR="/run/sendsigs.omit.d"

# we need to unmount /dev/pts/ and remount it later over the devtmpfs
unmount_devpts() {
  if mountpoint -q /dev/pts/; then
    umount -n -l /dev/pts/
  fi

  if mountpoint -q /dev/shm/; then
    umount -n -l /dev/shm/
  fi
}

# mount a devtmpfs over /dev, if somebody did not already do it
mount_devtmpfs() {
  if grep -E -q "^[^[:space:]]+ /dev devtmpfs" /proc/mounts; then
    mount -n -o remount,nosuid,size=$tmpfs_size,mode=0755 -t devtmpfs devtmpfs /dev
    return
  fi

  if ! mount -n -o nosuid,size=$tmpfs_size,mode=0755 -t devtmpfs devtmpfs /dev; then
    log_failure_msg "udev requires devtmpfs support, not started"
    log_end_msg 1
  fi

  return 0
}

create_dev_makedev() {
  if [ -e /sbin/MAKEDEV ]; then
    ln -sf /sbin/MAKEDEV /dev/MAKEDEV
  else
    ln -sf /bin/true /dev/MAKEDEV
  fi
}

# shell version of /usr/bin/tty
my_tty() {
  [ -x /bin/readlink ] || return 0
  [ -e /proc/self/fd/0 ] || return 0
  readlink --silent /proc/self/fd/0 || true
}

warn_if_interactive() {
  if [ "$RUNLEVEL" = "S" -a "$PREVLEVEL" = "N" ]; then
    return
  fi

  TTY=$(my_tty)
  if [ -z "$TTY" -o "$TTY" = "/dev/console" -o "$TTY" = "/dev/null" ]; then
    return
  fi

  printf "\n\n\nIt has been detected that the command\n\n\t$0 $*\n\n"
  printf "has been run from an interactive shell.\n"
  printf "It will probably not do what you expect, so this script will wait\n"
  printf "60 seconds before continuing. Press ^C to stop it.\n"
  printf "RUNNING THIS COMMAND IS HIGHLY DISCOURAGED!\n\n\n\n"
  sleep 60
}

make_static_nodes() {
  [ -e /lib/modules/$(uname -r)/modules.devname ] || return 0
  [ -x /bin/kmod ] || return 0

  /bin/kmod static-nodes --format=tmpfiles --output=/proc/self/fd/1 | \
  while read type name mode uid gid age arg; do
    [ -e $name ] && continue
    case "$type" in
      c|b|c!|b!) mknod -m $mode $name $type $(echo $arg | sed 's/:/ /') ;;
      d|d!) mkdir $name ;;
      *) echo "unparseable line ($type $name $mode $uid $gid $age $arg)" >&2 ;;
    esac

    if [ -x /sbin/restorecon ]; then
      /sbin/restorecon $name
    fi
  done
}


##############################################################################


[ -x $DAEMON ] || exit 0

# defaults
tmpfs_size="10M"

if [ -e /etc/udev/udev.conf ]; then
  . /etc/udev/udev.conf
fi

. /lib/lsb/init-functions

if [ ! -e /proc/filesystems ]; then
  log_failure_msg "udev requires a mounted procfs, not started"
  log_end_msg 1
fi

if ! grep -q '[[:space:]]devtmpfs$' /proc/filesystems; then
  log_failure_msg "udev requires devtmpfs support, not started"
  log_end_msg 1
fi

if [ ! -d /sys/class/ ]; then
  log_failure_msg "udev requires a mounted sysfs, not started"
  log_end_msg 1
fi

if [ ! -w /sys ]; then
  log_warning_msg "udev does not support containers, not started"
  exit 0
fi

if [ -d /sys/class/mem/null -a ! -L /sys/class/mem/null ] || \
   [ -e /sys/block -a ! -e /sys/class/block ]; then
  log_warning_msg "CONFIG_SYSFS_DEPRECATED must not be selected"
  log_warning_msg "Booting will continue in 30 seconds but many things will be broken"
  sleep 30
fi

# When modifying this script, do not forget that between the time that the
# new /dev has been mounted and udevadm trigger has been run there will be
# no /dev/null. This also means that you cannot use the "&" shell command.

case "$1" in
    start)
    if [ ! -e "/run/udev/" ]; then
        warn_if_interactive
    fi

    if [ -w /sys/kernel/uevent_helper ]; then
        echo > /sys/kernel/uevent_helper
    fi

    if ! mountpoint -q /dev/; then
        unmount_devpts
        mount_devtmpfs
        [ -d /proc/1 ] || mount -n /proc
    fi

    make_static_nodes

    # clean up parts of the database created by the initramfs udev
    udevadm info --cleanup-db

    # set the SELinux context for devices created in the initramfs
    [ -x /sbin/restorecon ] && /sbin/restorecon -R /dev

    log_daemon_msg "Starting $DESC" "$NAME"
    if start-stop-daemon --start --name $NAME --user root --quiet \
        --pidfile $PIDFILE --exec $DAEMON --background --make-pidfile \
        --notify-await; then
        # prevents udevd to be killed by sendsigs (see #791944)
        mkdir -p $OMITDIR
        ln -sf $PIDFILE $OMITDIR/$NAME
        log_end_msg $?
    else
        log_warning_msg $?
        log_warning_msg "Waiting 15 seconds and trying to continue anyway"
        sleep 15
    fi

    log_action_begin_msg "Synthesizing the initial hotplug events (subsystems)"
    if udevadm trigger --type=subsystems --action=add; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    log_action_begin_msg "Synthesizing the initial hotplug events (devices)"
    if udevadm trigger --type=devices --action=add; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi

    create_dev_makedev

    # wait for the systemd-udevd childs to finish
    log_action_begin_msg "Waiting for /dev to be fully populated"
    if udevadm settle; then
        log_action_end_msg 0
    else
        log_action_end_msg 0 'timeout'
    fi
    ;;

    stop)
    log_daemon_msg "Stopping $DESC" "$NAME"
    if start-stop-daemon --stop --name $NAME --user root --quiet \
        --pidfile $PIDFILE --remove-pidfile --oknodo --retry 5; then
        # prevents cryptsetup/dmsetup hangs (see #791944)
        rm -f $CTRLFILE
        log_end_msg $?
    else
        log_end_msg $?
    fi
    ;;

    restart)
    log_daemon_msg "Stopping $DESC" "$NAME"
    if start-stop-daemon --stop --name $NAME --user root --quiet \
        --pidfile $PIDFILE --remove-pidfile --oknodo --retry 5; then
        # prevents cryptsetup/dmsetup hangs (see #791944)
        rm -f $CTRLFILE
        log_end_msg $?
    else
        log_end_msg $? || true
    fi

    log_daemon_msg "Starting $DESC" "$NAME"
    if start-stop-daemon --start --name $NAME --user root --quiet \
        --pidfile $PIDFILE --exec $DAEMON --background --make-pidfile \
        --notify-await; then
        # prevents udevd to be killed by sendsigs (see #791944)
        mkdir -p $OMITDIR
        ln -sf $PIDFILE $OMITDIR/$NAME
        log_end_msg $?
    else
        log_end_msg $?
    fi
    ;;

    reload|force-reload)
    udevadm control --reload-rules
    ;;

    status)
    status_of_proc $DAEMON $NAME && exit 0 || exit $?
    ;;

    *)
    echo "Usage: /etc/init.d/udev {start|stop|restart|reload|force-reload|status}" >&2
    exit 1
    ;;
esac

exit 0