From: Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>
To: cygwin@cygwin.com
Subject: Re: How to query the value of %SystemDrive% in an empty environment?
Date: Wed, 07 Aug 2019 11:09:00 -0000 [thread overview]
Message-ID: <ebba0d18-d4d1-dd3c-bd52-b91489106cbf@ssi-schaefer.com> (raw)
In-Reply-To: <0f9d219c-a9ae-237a-afcf-9dcc5a13bc01@SystematicSw.ab.ca>
On 8/7/19 4:33 AM, Brian Inglis wrote:
> On 2019-08-06 09:20, Michael Haubenwallner wrote:
>> using 'env -i' to create an empty environment, the SYSTEMROOT and WINDIR
>> environment variables are preserved (or recreated):
>> $ /usr/bin/env -i /usr/bin/env
>> SYSTEMROOT=C:\Windows
>> WINDIR=C:\Windows
>> And with cygpath, there is the -A, -D, -H, -O, -P, -S, -W and even -F flags
>> to query the values for various directories.
>> Now what I've failed to find is how to query the value for the "SystemDrive"
>> environment variable.
>> The problem behind is that I'm using "vswhere.exe" to locate some Visual Studio
>> environment from within some scripts run via 'env -i', causing vswhere.exe to
>> create a directory named "%SystemDrive%" in the current working directory:
>> So I better ensure the SystemDrive environment variable is set for vswhere.exe.
>> Any ideas?
>
> There is a reg entry:
>
> $ head
> /proc/registry/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/SystemBootDevice;
> echo
> multi(0)disk(0)rdisk(1)partition(3)
>
> but how do you convert that to a device letter?
>
> SYSTEMDRIVE is a dynamic env var created at startup pointing to the boot drive
> letter. It is not instantiated anywhere else as far I could find. A number of
> low level reg entries use that env var. Only option is to pass it through:
Heck, even CreateEnvironmentBlock() relies on SYSTEMROOT env var being set,
otherwise returning things like ProgramData="%SystemDrive%\ProgramData".
>
> $ /usr/bin/env -i SYSTEMDRIVE="$SYSTEMDRIVE" /usr/bin/env
> SYSTEMDRIVE=C:
> SYSTEMROOT=C:\WINDOWS
> WINDIR=C:\WINDOWS
Feels like the Cygwin DLL better should try to keep SYSTEMDRIVE being set, no?
/haubi/ (about to prepare some patch)
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next prev parent reply other threads:[~2019-08-07 11:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 15:20 Michael Haubenwallner
2019-08-06 15:41 ` Corinna Vinschen
2019-08-06 15:47 ` Bill Stewart
2019-08-06 15:53 ` Corinna Vinschen
2019-08-06 16:10 ` Bill Stewart
2019-08-06 16:25 ` Corinna Vinschen
2019-08-06 17:08 ` Bill Stewart
2019-08-07 2:33 ` Brian Inglis
2019-08-07 11:09 ` Michael Haubenwallner [this message]
2019-08-07 11:19 ` Corinna Vinschen
2019-08-07 12:41 ` Michael Haubenwallner
2019-08-07 14:31 ` Corinna Vinschen
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