Edit network (eg. WiFi) information used by network-manager and merge from a cached copy.

neted

#!/bin/bash
# License::   GPLv3+
# Copyright:: 2017 Daniel Barrows
# Status::    beta
#
# This currently doesn't do any sanity checks on arguments.
#
# The most powerful function here is neted merge, which basically lets you
# compare and merge your local networks with some cached networks using meld,
# and then saves the changes, while handling all the necessary file and network
# permissions for you. Any existing network permissions may be lost.
#
# Currently these functions only accept directories of network descriptors. In
# the future they may accept network descriptor files directly.
#
# This code may be useful in other situations where permissions are an issue
# apart from just networks. Actually, generalizing it would probably improve the
# usability of this script as well.
#
# For outside code, I recommend calling neted rather than invoking functions
# directly. I do not intend to keep the functions as a stable API.


### CONSTANTS
[ -z $COLUMNS ] && COLUMNS="$(tput cols 2>/dev/null || echo 80)"
EXIT_HELP_MESSAGE=0
EXIT_USAGE_ERROR=7


### FUNCTIONS

show_usage(){
  cat <<EOS
  neted change-user-permissions USER [ DIR | FILE ]*
  neted copy SOURCE [ DEST ]
  neted copy-missing SOURCE DEST
  neted merge SOURCE DEST
  neted replace SOURCE [ DEST ]
  neted shell
EOS
}

neted_argerr(){
  [[ $# < 2 ]] || neted_argerr "neted_argerr requires 0 or 1 arguments."
  local message="$1"; [ -z "$message" ] && "Wrong number of arguments given."
  echo "ERROR: $message" >&2
  exit $EXIT_USAGE_ERROR
}

# usr here can be blank, a username, a full permissions argument, or empty.
# Anything that doesn't contain a semicolon is presumed to be a username.
neted_change_user_permissions(){
  local usr="$1"
  shift
  [ ! -z "$usr" ] && [ ! -z "${usr##*;*}" ] && usr="user:$usr:;"
  for filepath in "$@"; do
    if [ -d "$filepath" ]; then
      neted_change_user_permissions "$usr" "$filepath"/*
    else
      sed -Ei "s/^permissions=.*$/permissions=$usr/" "$filepath"
    fi
  done
}

neted_copy(){
  [[ $# < 3 ]] || neted_argerr "neted_copy requires 1 or 2 arguments."
  local source="$1"
  [ -z "$source" ] && neted_argerr 'No source given to neted_copy'
  local dest="$2"; [ -z "$dest" ] && dest=./

  [[ "${dest: -1}" == "/" ]] && dest="$dest/$( basename -- "$source" )"
  sudo cp -aiT "$source" "$dest"
  sudo chown -R "$USER:$USER" "$dest"
  chmod 666 "$dest"/*
}

# This really only makes sense if dest is system
neted_copy_missing(){
  [[ $# < 3 ]] || neted_argerr "neted_copy_missing requires 1 or 2 arguments."
  local source="$1"
  [ -z "$source" ] && neted_argerr 'No source given to neted_copy_missing'
  local dest="$2"; [ -z "$dest" ] && dest=/etc/NetworkManager/system-connections

  sudo cp -an "$source"/* "$dest/" \
  && sudo chown root:root "$dest"/* \
  && sudo chmod 600 "$dest"/* \
  && sudo nmcli connection reload

}

# This really only makes sense if dest is system
neted_replace(){
  [[ $# < 3 ]] || neted_argerr "neted_copy_missing requires 1 or 2 arguments."
  local source="$1"
  [ -z "$source" ] && neted_argerr 'No source given to neted_copy_missing'
  local dest="$2"; [ -z "$dest" ] && dest=/etc/NetworkManager/system-connections

  sudo rm "$dest"/* \
  && sudo cp -a "$source"/* "$dest/" \
  && sudo chown root:root "$dest"/* \
  && sudo chmod 600 "$dest"/* \
  && sudo nmcli connection reload

}

# Right now only the first argument is handled for permissions issues at both
# the file and the network levels.
# Usage eg.: neted_merge system $DIRECTORY_PATH
neted_merge(){
  [[ $# == 2 ]] || neted_argerr "neted_merge requires 2 arguments."
  local source="$1"
  local dest="$2"
  neted copy "$source" /tmp/system-connections \
  && neted change-user-permissions '' /tmp/system-connections \
  && meld /tmp/system-connections "$dest" \
  && neted change-user-permissions "$USER" /tmp/system-connections \
  && neted replace /tmp/system-connections "$source" \
  && rm -R /tmp/system-connections
}

# Autocomplete would be great here.
neted_shell(){
  [[ $# == 0 ]] || echo "WARNING: neted_shell arguments ignored: $*" >&2
  echo "Welcome to neted shell." \
       "Type 'help' for available commands, or 'quit' to exit."
  while read -p '> ' line; do
    case $line in
    q | quit | 'exit' ) break;;
    s | shell         ) echo "ERROR: Subshells not permitted." >&2;;
    h | -h | -? | help | --help | \
    cat                         | \
    u | change-user-permissions | \
    c | copy                    | \
    cm | copy-missing           | \
    m | merge                   | \
    r | replace                 ) neted $line;;
    *                           ) $line;;
    esac
  done
}

neted_cat(){
  [[ $# == 1 ]] || neted_argerr "neted_cat requires exactly 1 argument."
  sudo cat /etc/NetworkManager/system-connections/"$1"
}

### COMMAND LINE OPTIONS
neted(){
  command="$1"
  shift
  args=()

  for i in "$@"; do
    case "$i" in
    #-q  | --quiet         ) unset VERBOSE;;
    #-v  | --verbose       ) VERBOSE=true;;
    -h  | --help | '-?'   ) show_usage; return $EXIT_HELP_MESSAGE;;
    -*                    ) echo ERROR: unknown option: "'$i'" >&2
                            show_usage
                            return $EXIT_USAGE_ERROR;;
    system                ) args+=( "/etc/NetworkManager/system-connections" );;
    *                     ) args+=( "$i" );;
    esac
  done

  case $command in
  h | -h | -? | help | --help ) show_usage; return $EXIT_HELP_MESSAGE;;
  cat                         ) neted_cat                     "${args[@]}";;
  u | change-user-permissions ) neted_change_user_permissions "${args[@]}";;
  c | copy                    ) neted_copy                    "${args[@]}";;
  cm | copy-missing           ) neted_copy_missing            "${args[@]}";;
  m | merge                   ) neted_merge                   "${args[@]}";;
  r | replace                 ) neted_replace                 "${args[@]}";;
  s | shell                   ) neted_shell                   "${args[@]}";;
  *                           ) echo ERROR: unknown command: "'$command'" >&2
                                show_usage
                                return $EXIT_USAGE_ERROR;;
  esac
}

if [ "$(basename -- "$0")" = "neted" ]; then
  neted "$@"
fi