cygwin-3.1.0 and mintty from desktop shortcut

[Takashi Yano]

On Sun, 7 Jun 2020 00:15:59 -0600
Brian Inglis wrote:
> On 2020-06-06 19:35, Takashi Yano via Cygwin wrote:
> > On Sat, 06 Jun 2020 13:20:16 +0200
> > ASSI wrote:
> >> Takashi Yano via Cygwin writes:
> >>>> 1. Rename /usr/share/locale to something else, like local.bak.
> >>>> 2. Start mintty in the usual way.
> >>>> 3. Rename the directory from step 1 back to /usr/share/local.
> >>>> 4. Work just like the problem never existed either in the shell running
> >>>> inside the mintty or even start a new mintty.
> >>>
> >>> I guess renaming /usr/share/locale/locale.alias is enough.
> >>
> >> I've had some time to look into this problem again after having updated
> >> Cygwin to the latest and greatest.  Indeed, when
> >>
> >> /usr/share/locale/locale.alias
> >>
> >> gets renamed, the problem also goes away.  This is great because I don't
> >> really need the locale aliases for anything.  Btw, my laptop got
> >> upgraded to Win10 1909 (Enterprise) in the meantime, so the issue isn't
> >> specific to 1803 as was supected earlier.
> >>
> >> I then tried to figure out what exactly causes the problem and it turns
> >> out that it's the _presence_ of this file with the additional condition
> >> that it must not be owned by the user starting the mintty/shell.  Since
> >> I install Cygwin on my work laptop with a different (admin) account and
> >> not my (non-admin) user account, that explains why I am seeing the
> >> problem there and not on other machines.  Before you are going to
> >> suggest that it's the admin vs. non-admin rights: no, if I create a
> >> locale.alias with my user account (either as an empty file or a copy of
> >> the backup file), then the admin account is unable to start a shell in
> >> mintty successfully.  I have no idea why the ownership of a file that
> >> onnly should get read (and is readable by everyone) would have the
> >> effect I'm seeing, but maybe that gives the clue on where to look for a
> >> fix.
> > 
> > Thanks for the additional information. I tested the following steps
> > to confirm if the problem can be reproduced.
> > 
> > 1. Enable Administrator account.
> > 2. Remove all groups from account yano other than Users.
> > 3. Install cygwin for all with gettext package as Administrator.
> > 4. Run mintty from desktop shortcut as Administrator.
> > 5. Run mintty from desktop shortcut as yano.
> > 
> > Both 4 and 5 successfully open mintty window with shell.
> > 
> > I wonder what is the difference between my environment and yours.
> 
> Locale setting?
> 
> fhandler_tty.cc(fhandler_pty_slave::setup_locale)@2854 calls
> get_langinfo@2768 calls@2781
> nlsfuncs.cc(__set_locale_from_locale_alias)@1462
> which opens /usr/share/locale/locale.alias@1472.
> 
> One problem I see with that is that __set_locale_from_locale_alias is meant to
> be called when loadlocale fails with an unrecognized locale, but in
> get_langinfo@2778 if the locale is not found, it is defaulted to C before
> __set_locale_from_locale_alias is called, defeating the purpose:
> 
>   const char *locale = __loadlocale (&loc, LC_CTYPE, new_locale);
>   if (!locale)
>     locale = "C";
> 
>   char tmp_locale[ENCODING_LEN + 1];
>   char *ret = __set_locale_from_locale_alias (locale, tmp_locale);
>   if (ret)
>     locale = tmp_locale;

Hmm..., you are right. Furthermore, __set_locale_from_locale_alias()
here is completely unnecessary since it is already processed in
__loadlocale().

I will remove that code.

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>