Re: Commands with passwords as options

[Julien Nicoulaud <julien.nicoulaud@xxxxxxxxx>]

2011/2/2 Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>

> On Feb 1, 10:15pm, Julien Nicoulaud wrote:
> }
> } Some commands take passwords as option values, which is not very
> } secure... I was wondering if there is some way to handle that, for
> } example through a custom completer.
>
> I don't know about a custom completer -- it's pretty difficult to
> have the completion system go off and do something interactive in
> the middle, at least not without the display ending up hopelessly
> muddled afterward -- but it should be possible to implement it as
> a widget.
>
> send-invisible() {
>  emulate -L zsh
>  # Shamelessly cribbed from read-from-minibuffer.
>
>  # send-invisible reads a line from the terminal, displaying an
>  # asterisk for each character typed.  It stores the line in the
>  # global variable INVISIBLE, and when finished reading, inserts
>  # the string ${INVISIBLE} into the original command buffer.
>
>  # If one argument is given, it is the prompt.  The default is
>  # "Non-echoed text: "
>
>  # If two or three arguments are given, they form the prefix and
>  # suffix of the inserted INVISIBLE.  Defaults are '${' and '}'
>  # but these can be replaced, for example with '"${' and '}"' to
>  # enclose the whole word in double quotes, or '${(z)' and '}' to
>  # split the value of $INVISIBLE like the shell parser.
>
>  # Hide the value of INVISIBLE in any output of set and typeset
>  typeset -g -H INVISIBLE=
>
>  local pretext="$PREDISPLAY$LBUFFER$RBUFFER$POSTDISPLAY"$'\n'
>
>  # Can't directly make these locals because send-invisible is
>  # called as a widget, so these special variables are already
>  # local at the current level and wouldn't get restored
>  local save_lbuffer=$LBUFFER
>  local save_rbuffer=$RBUFFER
>  local save_predisplay=$PREDISPLAY
>  local save_postdisplay=$POSTDISPLAY
>  local -a save_region_highlight
>  save_region_highlight=("${region_highlight[@]}")
>
>  {
>    local lb rb opn=${2:-'${'} cls=${3:-'}'}
>    LBUFFER=
>    RBUFFER=
>    PREDISPLAY="$pretext${1:-Non-echoed text: }"
>    POSTDISPLAY=
>    region_highlight=("P${(m)#pretext} ${(m)#PREDISPLAY} bold")
>
>    while zle -R && zle .read-command
>    do
>      # There are probably more commands that should go into
>      # the first clause here to harmlessly beep, because ...
>      case $REPLY in
>      (send-invisible|run-help|undefined-key|where-is|which-command)
>        zle .beep;;
>      (push-*|send-break) INVISIBLE=;&
>      (accept-*) break;;
>      (*)
>        LBUFFER=$lb
>        RBUFFER=$rb
>        zle $REPLY      # ... this could expose something
>        lb=$LBUFFER
>        rb=$RBUFFER
>        INVISIBLE=$BUFFER
>        LBUFFER=${(l:$#LBUFFER::*:):-}
>        RBUFFER=${(l:$#RBUFFER::*:):-}
>        ;;
>      esac
>    done
>  } always {
>    LBUFFER=$save_lbuffer
>    RBUFFER=$save_rbuffer
>    PREDISPLAY=$save_predisplay
>    POSTDISPLAY=$save_postdisplay
>    region_highlight=("${save_region_highlight[@]}")
>    zle -R
>
>    # Now that the highlight has been restored with all the old
>    # text and cursor positioning, insert the new text.
>    LBUFFER+=${INVISIBLE:+${opn}INVISIBLE${cls}}
>  }
> }
> zle -N send-invisible
>
> Perfect, thank you !

You can unset INVISIBLE in precmd too:
  unset_invisible () {unset INVISIBLE}
  add-zsh-hook precmd unset_invisible


> } Ideally, I here is how it should behave:
> }  - When reaching an option which expected value is a password, prompt for
> it
> } and read it from stdin
>
> If you can figure out how to auto-invoke the above in these circumstances,
> go for it.  Possibly something in zle-line-init that examines the word
> at the end of $LBUFFER.
>
> I think the widget approach is the only one that will work in every case...


>  }  - Do not display it in the buffer (just replace it with "XXXX" for
> example)
> }  - When accepting the buffer, replace the displayed buffer with the real
> one
> }  - Save the displayed buffer in the history rather than the real one
>
> I think the above covers all of this.
>