install

#!/bin/bash

# This script has two modes; one when run on the primary machine, 
# and another to install on the secondary (remote) machine.

# Primary machine:  ./install [user@]remotehost [/remote/path]

# Secondary machine: ./install . [/local/path]

# That is, if the first argument is a '.' character, then the
# script runs in secondary mode, installing to the local machine.
# Otherwise, the script creates SSH keys to the secondary machine,
# copies itself and its dependencies to that machine and then
# launches it with arguments "." "$2"

test_ssh() {
  ssh -n $1 <<< true &>/dev/null
}

mksshkeys() {
  # Requires interactivity

  if [ $# -ne 1 ]
  then
    echo 'Usage: mksshkeys [user@]host'
    exit 1
  fi
  if [ ! -d $HOME/.ssh ]
  then
    mkdir $HOME/.ssh
    chmod 0755 $HOME/.ssh
  fi
  if [ ! -f $HOME/.ssh/id_rsa.pub ]
  then
    echo 'Generating RSA certificate'
    ssh-keygen -f $HOME/.ssh/id_rsa -t rsa -a 100 -P ''
  fi

  echo "Installing ED25519 certificate on $1"

  (
    echo 'mkdir -p $HOME/.ssh ; chmod 0755 $HOME/.ssh ; '
    echo 'cat << EOF >> $HOME/.ssh/authorized_keys'
    cat $HOME/.ssh/id_rsa.pub
    echo 'EOF'
    echo 'chmod 0600 $HOME/.ssh/authorized_keys'
  ) | ssh $1
}


primary_mode() {
  TARGET_HOST="$1"
  TARGET_DIR="$2"
  test_ssh $TARGET_HOST || mksshkeys $TARGET_HOST
  scp "$0" ${TARGET_HOST}:/tmp
  if ssh -tX ${TARGET_HOST} /tmp/$(basename $0) . "${TARGET_DIR}"
  then
    TMP=$(mktemp)
    grep -v "^${TARGET_HOST} " ~/.upd-remote > $TMP
    echo "${TARGET_HOST} ${TARGET_DIR:-~/src}" >> $TMP
    mv $TMP ~/.upd-remote
  else
    echo "Install failed!"
  fi
}

secondary_mode() {
  if [ -z "$2" ]
  then
    TARGET_DIR="$(realpath ~/src)"
  else
    TARGET_DIR="$(realpath "$2")"
  fi
  echo "Creating $TARGET_DIR"
  mkdir -p "$TARGET_DIR" || ( echo "Could not create target dir $TARGET_DIR"; exit 1 )

  SUDOER=/etc/sudoers.d/upd-$(whoami)
  until sudo -n true
  do
    echo Enter password on remote machine $(hostname) to allow passwordless sudo
    sudo tee $SUDOER >/dev/null  <<< "$(whoami)  ALL=(ALL) NOPASSWD: ALL"
  done
  echo "Created $SUDOER"

  if ! which git &>/dev/null
  then
    echo "Installing git"
    sudo apt-get update
    sudo apt-get -y install git
  fi

  cd "$TARGET_DIR"
  echo "Checking out upd.git repo"
  git clone https://github.com/jbreadner/upd.git
  sudo tee /etc/profile.d/upd.sh <<< 'export PATH=$PATH:'$(pwd)'/upd'

  for scriptlet in "${TARGET_DIR}"/upd/available/*
  do
    "$scriptlet" --install
  done

  echo "Cleaning up"
  rm -f "$0"
  echo "Installed"
  exit 0
}

if [ $# -lt 1 -o $# -gt 2 -o "$1" = "-h" -o "$1" = "--help" ]
then
  echo "Usage: ./install [user@]host [/remote/path]"
  echo "Installs the 'upd' scripts on the remote host."
  echo Called as: $0 "${@}"
  exit 1
fi

if [ "$1" = "." ]
then
  secondary_mode "$@"
else
  primary_mode "$@"
fi