Getting the Chocolatey shimgen generated shim target
Posted by jpluimers on 2023/10/10
For tomorrow’s post Ookla speedtest CLI for Windows has some undocumented arguments to accept license and GDPR I neede the full path to the speedtest.exe which I had installed using Chocolatey.
I know chocolatey uses a shim that redirects to the actual executable, so a simple where speedtest.exe would not cut it.
My guess would be that the generated shim allowed to either get the target pathname out, or have the target pathname encoded in it.
Luckily the first applies: a few of the shim command-line parameters are in [Wayback/Archive] Chocolatey Software Docs | Executable shimming (like symlinks but better):
You pass these arguments to an executable that is a shim (e.g. executables in the bin directory of your Chocolatey install, not choco.exe):
--shimgen-help– shows this help menu and exits without running the target--shimgen-log– logging is shown on command line--shimgen-waitforexit– explicitly tell the shim to wait for target to exit – useful when something is calling a gui and wanting to block – command line programs explicitly have waitforexit already set.--shimgen-exit– explicitly tell the shim to exit immediately.--shimgen-gui– explicitly behave as if the target is a GUI application. This is helpful in situations where the package did not have a proper .gui file.--shimgen-usetargetworkingdirectory– set the working directory to the target path. Useful when programs need to be running from where they are located (usually indicates programs that have issues being run globally).--shimgen-noop– Do not actually call the target. Useful to see what would happen if you ran the command.
But the below dumps show more more (using [Wayback/Archive] Strings – Windows Sysinternals | Microsoft Docs, [Wayback/Archive] clip | Microsoft Docs and post-processing in [Wayback/Archive] Notepad++).
Back to the second solution,
strings C:\ProgramData\chocolatey\bin\speedtest.exe | findstr speedtest.exe
showed
speedtest.exe ..\\lib\speedtest\tools\speedtest.exe Cannot find file at '..\\lib\speedtest\tools\speedtest.exe' ( speedtest.exe speedtest.exe
And towards the first,
strings C:\ProgramData\chocolatey\bin\speedtest.exe | clip
resulted in this fragment:
============== Shim Arguments ============== You can pass the following arguments to a shim: * shimgen-help - shows this help menu and exits without running the target * shimgen-log - logging is shown on command line * shimgen-waitforexit - explicitly tell the shim to wait for target to exit - useful when something is calling a gui and wanting to block - command line programs explicitly have waitforexit already set * shimgen-exit - explicitly tell the shim to exit immediately. * shimgen-gui - explicitly behave as if the target is a GUI application. This is helpful in situations where the package did not have a proper .gui file. * shimgen-usetargetworkingdirectory - set the working directory to the target path. Useful when programs need to be running from where they are located (usually indicates programs that have issues being run globally) * shimgen-noop - Do not actually call the target. Useful to see what would happen if you ran the command.
Based on it, I found the source code at [Wayback/Archive] shimgen/ShimProgram.cs at master · chocolatey/shimgen in repository [Wayback/Archive] chocolatey/shimgen: This repository exists to file issues against shimgen (despite there being no possibilities to report issues).
That confirmed I could just use shimgen-noop without slashes or dashes, which got me this output:
C:\temp> speedtest shimgen-noop [shim]: Set up Shim to run with the following parameters: path to executable: C:\ProgramData\chocolatey\lib\speedtest\tools\speedtest.exe working directory: C:\bin is gui? False wait for exit? True command (optional): [shim]: Command line 'speedtest shimgen-noop' [shim]: Current process '"C:\ProgramData\chocolatey\bin\speedtest.exe"' [shim]: Command line after removing process 'speedtest shimgen-noop' [shim]: Shifting off the first argument since process didn't catch it [shim]: Arguments after removing shimgen args - 'shimgen-noop' [shim]: Arguments are 'shimgen-noop'
So I wrote this short batch-file choco-get-shim-target-path.bat:
:: https://wiert.wordpress.com/?p=103228 :: https://wiert.wordpress.com/?p=75096 :: https://stackoverflow.com/questions/2541767/what-is-the-proper-way-to-test-if-a-parameter-is-empty-in-a-batch-file/2544545#2544545 :: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/for :: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/findstr :: https://superuser.com/questions/1373772/batch-file-dir-findstr-within-a-for-loop/1373793#1373793 @echo off if "%~1" == "" goto :help :: get the line starting with "path", then take everything starting from the 4th space separated word for /f "tokens=4*" %%o IN ('"%~1" shimgen-noop ^| findstr ^^path') do echo %%o goto :eof :help echo Executes a Chocolatey shimgen generated shim with parameter "shimgen-noop" echo to get the referring path. echo Requires one parameter: shim echo This parameter is the shim to execute and get the target path from. echo See also: https://github.com/chocolatey/shimgen
Since I keep forgetting how to:
handle empty parameters, windows – What is the proper way to test if a parameter is empty in a batch file? – Stack Overflow:
You can use:
IF "%~1" == "" GOTO MyLabelto strip the outer set of quotes. In general, this is a more reliable method than using square brackets because it will work even if the variable has spaces in it.
escape pipe (|) characters with a caret (^) as ^|, Get the full exe path name of running processes.:
PowerShell Get-Process %* ^| Format-List Path
Some more tricks used are documented in:
- [Wayback/Archive] for | Microsoft Docs
- [Wayback/Archive] findstr | Microsoft Docs
- [Wayback/Archive] command line – Batch File, dir | findstr within a for loop – Super User (thanks [Wayback/Archive] Gumbi and [Wayback/Archive] LotPings):
escape the pipe symbol
^|to pass it to the secondarycmd.exewhich is executed behind the scenes. - [Wayback/Archive] windows – What is the proper way to test if a parameter is empty in a batch file? – Stack Overflow (thanks [Wayback/Archive] jamesdlin and [Wayback/Archive] blak3r)
–jeroen
The Wiert Corner - irregular stream of stuff 
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