Re: [PATCH] Add a simple getpass() for MinGW

[Johannes Sixt <j6t@kdbg.org>]

Johannes Schindelin schrieb:
> This should be replaced with a graphical getpass() at some stage.
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
> 
> 	I saw it coming that I had to do this.

There are two callers of getpass: One is in imap-send.c, but we don't 
build it on Windows. The other is in http.c. But notice that this is only 
built if NO_CURL is not defined, yet, upstream git defines it in the MinGW 
section, and so this patch alone is not needed in upstream git.

I see you have removed NO_CURL = YesPlease in 4msysgit.git. You should 
make it a part of a series that removes NO_CURL = YesPlease from the MinGW 
section.

>  compat/mingw.c |   15 +++++++++++++++
>  1 files changed, 15 insertions(+), 0 deletions(-)
> 
> diff --git a/compat/mingw.c b/compat/mingw.c
> index d50186e..2ab5bbe 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1157,3 +1157,18 @@ int link(const char *oldpath, const char *newpath)
>  	}
>  	return 0;
>  }
> +
> +char *getpass(const char *prompt)
> +{
> +	struct strbuf buf = STRBUF_INIT;
> +
> +	fputs(prompt, stderr);
> +	for (;;) {
> +		char c = _getch();
> +		if (c == '\r' || c == '\n')
> +			break;
> +		strbuf_addch(&buf, c);
> +	}
> +	fputs("\n", stderr);
> +	return strbuf_detach(&buf, NULL);
> +}

Where do the callers get the prototype from (on MinGW)? Usually, we have 
to have a corresponding function declaration in compat/mingw.h for 
functions that are missing on Windows.

 From http://opengroup.org/onlinepubs/007908775/xsh/getpass.html:

   The return value points to static data whose content may be overwritten
   by each call.

I'm not saying that you should use a fixed-size static character array, 
but only that you should not leak memory on each call ;) (But not even 
that is very important; I'm just summarizing the research I did because I 
was wondering what would happen to the returned buffer.)

Apart from that, the implementation looks good. (_getch(), according to 
the docs on MSDN, doesn't echo the input.)

-- Hannes