On 23/08/2022 18:27, Christian Franke wrote:
> Jon Turney wrote:
>> On 12/07/2022 13:50, Jon Turney wrote:
>>> [Replying to the right list this time...]
>>> On 09/07/2022 13:21, Christian Franke wrote:
>> [...]
>>>>
>>>> The UserSettings ctor has a somewhat hidden side effect which sets 
>>>> root_scope correctly:
>>>>
>>>>   UserSettings::UserSettings(...);
>>>>    open_settings("setup.rc", ...);
>>>>     io_stream::open("cygfile:///etc/setup/setup.rc", ...);
>>>> io_stream_cygfile::io_stream_cygfile("/etc/setup/setup.rc", ...);
>>>>       get_root_dir_now();
>>>>        read_mounts("");
>>>>         read_mounts_nt("");
>>>>          root_scope = isuser ? IDC_ROOT_USER : IDC_ROOT_SYSTEM;
>>>>
>>>> Conclusion: Regression introduced Feb 24, 2012 (befc9dd).
>>>>
>>>
>>> Thanks for tracking this down.
>>>
>>> That just seems... fractally wrong.
>>
>> I kind of lost track of this.  Is there anything else needed to fix 
>> the original problem here?  Or is it solved by the change to defer 
>> setting the group until after root_scope is known?
> 
> The group seems to be correctly set now.
> 
> An old problem still remains: root_scope always ends up as 
> IDC_ROOT_SYSTEM if setup is run elevated, regardless off GUI setting. 
> Apply the temporary patch from here to see what happens:
> https://sourceware.org/pipermail/cygwin-apps/2022-July/042151.html

Ah, right, I remember now.

I think having read_mounts() have a side effect of setting root_scope is 
just nonsense now (it might have made some sense back in the day when 
the mount table was also stored in the registry).

So, how about the attached?

(We should perhaps also set the installation root directory to something 
other than C:\cygwin64 if a non-admin user, since they are unlikely to 
be able to write there in current windows versions, but that's difficult 
from a sequencing point of view in that dialog, and for backwards 
compatibility)

> Possibly difficult to fix, in particular in conjunction with later 
> changes via [< Back] button. An easier approach: Remove the GUI setting 
> and connect root_scope to -B option.

Looking for that option is not correct, because we might be running 
without -B, but from an already elevated shell.  I think checking 
nt_sec.isRunAsAdmin() would be the correct test.