Re: [PATCH 2/3] getpwuid(mingw): provide a better default for the user name

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Oct 16, 2018, 12:38 UTC
Message-ID: <nycvar.QRO.7.76.6.1810161436480.4546@tvgsbejvaqbjf.bet>
In-Reply-To: <CAPig+cRbOOrC5_jCnR2ohMZWoYXfNqvWtj3m_JTpudJhV1mQng@mail.gmail.com>

Hi Eric,

On Mon, 15 Oct 2018, Eric Sunshine wrote:

Show 17 quoted lines

> On Mon, Oct 15, 2018 at 5:47 AM Johannes Schindelin via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
> > We do have the excellent GetUserInfoEx() function to obtain more
> > detailed information of the current user (if the user is part of a
> > Windows domain); Let's use it.
> > [...]
> > Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> > ---
> > diff --git a/compat/mingw.c b/compat/mingw.c
> > @@ -1798,6 +1799,33 @@ int mingw_getpagesize(void)
> > +static char *get_extended_user_info(enum EXTENDED_NAME_FORMAT type)
> > +{
> > +       DECLARE_PROC_ADDR(secur32.dll, BOOL, GetUserNameExW,
> > +               enum EXTENDED_NAME_FORMAT, LPCWSTR, PULONG);
> > +       static wchar_t wbuffer[1024];
> 
> Does this need to be static? It's not being returned to the caller.

It does not. Fixed.

> > +       len = ARRAY_SIZE(wbuffer);
> > +       if (GetUserNameExW(type, wbuffer, &len)) {
> > +               char *converted = xmalloc((len *= 3));

Oh wow. I *just* realized this. It is an off-by-one: the `xmalloc()` call needs to receive `len + 1` to accommodate for the trailing NUL. Will fix, too.

Ciao, Dscho

Show 12 quoted lines

> > +               if (xwcstoutf(converted, wbuffer, len) >= 0)
> > +                       return converted;
> > +               free(converted);
> > +       }
> 
> If xwcstoutf() fails, 'converted' is freed; otherwise, the allocated
> 'converted' is stored in the caller's statically held 'passwd' struct.
> Okay.
> 
> > +       return NULL;
> > +}
>