Launch games under the correct user account on Windows

[cgutman]

Description

This implements a new platf::run_unprivileged() function that can be used (on Windows, currently) to launch a process as the active console user (including their environment variables).

In order to make this work, I had to fix issues with the way we derive the working directory if one is not provided. That required adding a dependency on libboost-program-options for boost::program_options::split_unix() to perform proper command-line parsing to retrieve the actual binary name.

This could definitely use some testing since there are a ton of use cases to cover.

Screenshot

Issues Fixed or Closed

• Resolves #521
• Fixes Applications not started as normal user #546

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[psyke83]

I believe that something may be wrong with path handling (but it applies to this PR and not #599). I tested with and without the complementary PR in case it helps to troubleshoot.

Test case (3 created test applications)

• Add Notepad1, with command as notepad
• Add Notepad2, with command as C:\Windows\System32\notepad.exe
• Add Notepad3, with command as C:\Windows\System32\notepad.exe and working directory as C:\Windows\System32\

Results:

• Nightly: Notepad1 fails (Warning: Couldn't run [notepad.exe]: System: The filename, directory name, or volume label syntax is incorrect). Notepad2 and Notepad3 work. I presume this is expected.
• Fix PATH variable handling on Windows #599: identical to nightly.
• Launch games under the correct user account on Windows #600: Notepad1 and Notepad3 works. Notepad2 fails with an error in Moonlight-QT: GeForce Experience returned error: Malformed GFE XML (missing root element) (Error -1), but nothing logged in Sunshine.
• Fix PATH variable handling on Windows #599 + Launch games under the correct user account on Windows #600: identical to Fix PATH variable handling on Windows #599 alone.

In summary, this PR makes notepad available (as it is in $Path), but C:\Windows\System32\notepad.exe fails to launch unless you manually add the working directory (which should not be necessary according to the Web UI's description).

[ReenigneArcher]

Looks like flatpak is failing to find boost now... not sure why: https://github.com/cgutman/LB_Sunshine/blob/d9107cdbfc5be261f50c5752badd3d209ccfcedc/packaging/linux/flatpak/dev.lizardbyte.sunshine.yml#L31

[cgutman]

OK, I think I've taken care of all the issues.

• I've changed the behavior for detached commands to use the given working directory as discussed with @ReenigneArcher on Discord (previously working directory was unset for those commands)
• Fixed working directory lookup issues caused by incorrect command parsing (Notepad1, 2, and 3 from @psyke83 's test should be working now)
• Switched from ANSI to Unicode functions for process and environment creation. I verified Unicode support is working with non-ASCII working directories, commands, and environment variables (both in the user environment block and from apps.json in env).
• Fixed Flatpak build by adding missing program_options library)
• Fixed clang-format issue (seems to disagree with my local clang-format but I'll defer to the bot)

[ReenigneArcher]

Fixed clang-format issue (seems to disagree with my local clang-format but I'll defer to the bot)

If you have any suggestions for changes to the .clang-format file, I'm happy to discuss. That file was provided to me early after I took over sunshine. One thing I personally don't like is the alignment of variable values, but I guess that's normal in c++.

[ReenigneArcher]

Several users on the discord had tested this build and I don't recall any issues. We would likely get more testing if merged into nightly.

This PR is not ready to merge.

[cgutman]

platf::run_unprivileged() changes:

• Added the ImpersonateLoggedOnUser() call to ensure that access checks are done against the user token rather than our SYSTEM token. This also allows launching apps on a network share or network drive.
• Addressed handle inheritance issues in a cleaner way (using PROC_THREAD_ATTRIBUTE_HANDLE_LIST rather than manually disabling inheritance on Sunshine's own std handles)
• Added CREATE_BREAKAWAY_FROM_JOB to handle changes in Spawn Sunshine.exe in a job object, so it is terminated if SunshineSvc.exe dies #602 that would otherwise terminate the child process if SunshineSvc died
• Added CREATE_NEW_CONSOLE to handle the case where log output is not redirected and incorrectly ends up in Sunshine's own log file
• Removed bp::child() fallback if CreateProcessAsUser() fails. I left that fallback in place just in case CreateProcessAsUser() failed when running as non-admin, but that case seems to work just fine (CreateProcessAsUser() and ImpersonateLoggedOnUser() using your own user token requires no additional permissions).

Log file fixes:

• Fixed Unicode log file path handling on Windows (previously, attempts to use non-ANSI log file paths would silently fail)
• Added _SH_DENYNO to ensure reopening log files for applications that are still running will not fail with a sharing violation.

These changes also fix the crash that we saw with UWP notepad.exe with the previous version of this PR.

[Michoko92]

Awesome job! 👍

[exalented]

With the 17 release I can no longer launch an app on linux without sunshine core dumping:
Platform: Arch / Sway / Nvidia, running AUR package.

Warning: run_unprivileged() is not yet implemented for this platform. The new process will run with Sunshine's permissions.
terminate called after throwing an instance of 'boost::process::process_error'
  what():  killpg(2) failed in terminate: Invalid argument
Aborted (core dumped)