Launch Linux and Windows through a launcher, with SDK dependency by sunmachine · Pull Request #2019 · NeotokyoRebuild/neo

sunmachine · 2026-07-14T02:49:20Z

Description

NT;RE ships its own engine binaries on its own appid; only the HL2/platform assets come from Source SDK Base 2013 MP, mounted through the |appid_243750| search paths in gameinfo.txt. Valve's stock launcher assumes the opposite layout and runs the game from the SDK install, which is why the SDK asset mounts silently fail on Linux. This PR makes launcher_main a real standalone mod launcher: the game runs from its own install with its own bin/, and the SDK is nothing more than an asset dependency.

Much of its functionality can be found in Valve's hl2.sh script (the old ntre.sh script), except now ported over directly into the launcher.

Details:

Linux launches in-process like Windows: own bin/linux64 LD_LIBRARY_PATH, dlopen our launcher.so, no hl2.sh or Valve bootstraps.
Works around the engine opening |appid_243750| mounts with the SDK name partly lowercased (silent ENOENT on case-sensitive filesystems) via self-repairing symlink.
Missing or broken SDK install shows an error dialog instead of crashing in MXR_LoadAllSoundMixers.
No -game in launch options; derived from the binary name (neo_linux64 -> neo).
-wait_for_debugger now works on Linux.
CMake: NEO_MOD_APPID defaults to 3172910; opt-in NEO_INSTALL_LAUNCHER packages the launcher per the NEO_INSTALL_* conventions. No CI changes.
The earlier SDK_EXEC_DIR fix is removed, superseded by this layout.
Dev setups are unaffected; sourcemods/ and explicit -game launches don't use this launcher.

Verified on Linux via the Steam Play button (-steam only): full bot match with all SDK content mounted, error dialog when the SDK files are missing, stale symlink repaired automatically. In-game path dump in the comments.

Warning

The Windows flow is code-complete but untested; needs a run on a real Windows install, including with the SDK absent.

Depot follow-ups (not this PR): launcher binaries at the install root, launch options pointing at them with -steam only, drop the renamed Valve bootstraps, preserve bin/ filename casing (engine dlopens GameUI.so etc. by exact name).

Testing on Linux

Build (branch: linux-build-fix)

From src/, in a Steam Runtime 3.0 (sniper) environment:
- cmake --preset linux-release
- cmake --build build/linux-release --target launcher_main
Output: src/build/linux-release/launcher_main/neo_linux64

Overlay onto Steam (local testing only)

Set NT;RE to the sdk-dependency-testing branch, "-steam only (dev testing)" launch option.
- You don't need to do a compatibility override for Sniper, it's already configured depot-side.
Copy neo_linux64 into ~/.local/share/Steam/steamapps/common/NEOTOKYOREBUILD/ (next to neo/).
NOTE: This step can be skipped if you're using the new Launch game without script (dev testing) option at Play-time.
- Replace ntre.sh there with this shim, then chmod +x neo_linux64 ntre.sh:
```
#!/bin/bash
exec "$(cd "${0%/*}" && pwd)/neo_linux64" "$@"
```
Press Play. Optional: -condebug in launch options writes neo/console.log.

Depot Changes

ntre.sh isn't required anymore.
The depot will need to execute from neo_linux64 as the shim's functionality was ported into the executable.

Toolchain

Windows MSVC VS2022
Linux GCC 10 Sniper 3.0

Linked Issues

fixes #
related #

TODO

Test Windows.
~~Update CI so that we can switch NEO_BUILD_LAUNCHER to ON by default.~~
- To be done in a follow-up PR.

sunmachine · 2026-07-15T12:36:08Z

Marking as a draft for now; this proved the problem and POC for the fix (with the patch POC in discord), but it needs to be tidied up before proper review.

sunmachine · 2026-07-15T12:36:37Z

Fix-proof-of-concept is here: https://discord.com/channels/1235346473827434517/1526783378718855268/1526787211507535954

DESTROYGIRL · 2026-07-15T16:10:36Z

Windows build @ sunmachine#1

Rename the launcher binary to neo_linux64: Linux cannot have both the executable and the game/neo mod directory under the same name at the install root, and GetExecutableModName strips the _linux64 suffix so the default -game dir is still neo. Add src/common to the include path and include tier1/strtools.h before steam_api.h, since our patched matchmakingtypes.h uses V_strcpy_safe. When NEO_COPY_LIBRARIES is on, also stage libsteam_api.so into game/bin/linux64/ where the launcher dlopens it.

added neo ifdefs also

steam_appid.txt written by the launcher now identifies the mod without requiring -DNEO_MOD_APPID at configure time.

Follows the existing NEO_INSTALL_* install/CPack convention; produces a -launcher artifact holding the launcher binary for the install root. steam_api already ships with the engine binaries in bin/.

The launcher now loads binaries from its own directory on both platforms. The Source SDK Base 2013 MP install remains a required asset dependency checked at startup, because gameinfo.txt mounts hl2/platform content from it, but it is no longer used as an execution root and SDK_EXEC_DIR is no longer set. Windows also gains the default -game injection the POSIX path already had (neo_win64.exe -> -game <root>\neo). The Windows flow is untested and needs scrutiny before use.

The launcher now mirrors the Windows flow: it prepends its own bin/linux64 to LD_LIBRARY_PATH (re-exec'ing itself once, since the dynamic linker reads the variable only at startup), loads launcher.so from the mod's own install, and calls LauncherMain directly. Environment obligations of the stock launch script are replicated: working directory at the install root, fd soft limit raised to 2048, __GL_THREADED_OPTIMIZATIONS, ENABLE_PATHMATCH when pathmatch.inf exists, and re-launch on exit status 42. No SDK Base binaries or scripts are involved in the launch chain anymore.

The engine opens |appid_243750| search paths with the final word of the SDK Base 2013 Multiplayer folder name lowercased, which silently mounts nothing on case-sensitive filesystems (observed via strace: every SDK-content open used ".../Source SDK Base 2013 multiplayer/..."). The launcher now creates a symlink under that mangled name pointing at the real install when the path does not already resolve. Failure to create it degrades to a warning.

readlink does not NUL-terminate its buffer. The result feeds GetBaseDir, execv, and argv[0], so an unterminated path could carry stack garbage into every downstream path computation.

The debugger-wait helpers existed but nothing called them, so the flag did nothing. Wait right after the bootstrap re-exec, before any Steam or engine work, so a debugger can attach to the process that loads the engine.

DESTROYGIRL

Works and compiles without warning on windows. Tested playing on a v30 dedicated server, no issues noticed.

Tested:

Running on Windows works
Running on Windows without SDK 2013 already installed works
Running on Linux works, though I noticed some console errors regarding shaders, unsure if its expected. A more seasoned linux player can verify
Running on Linux without SDK 2013 already installed works (check comments)

DESTROYGIRL · 2026-07-18T22:00:06Z

A TODO on this is to create a workflow for github actions that produces a new archive containing the launcher as part of the builds
(maybe this can be handled in a different PR...?)

DESTROYGIRL

Working on linux / windows with SDK install prompt as well

sunmachine · 2026-07-19T14:49:52Z

Marking TODOs as satisfied.

Masterkatze

LGTM

sunzenshen requested a review from a team July 14, 2026 03:38

Masterkatze reviewed Jul 14, 2026

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Comment thread src/CMakeLists.txt Outdated

sunmachine marked this pull request as draft July 15, 2026 03:34

DESTROYGIRL self-assigned this Jul 15, 2026

sunmachine and others added 5 commits July 18, 2026 12:14

Create a new launcher target for Linux.

78a1f24

Ignore the Linux launcher binary and its runtime steam_appid.txt

df74497

windows build for launcher main

756ef86

added neo ifdefs also

Update .gitignore

3977f72

sunmachine force-pushed the linux-build-fix branch from ef21e47 to 3977f72 Compare July 18, 2026 16:14

sunmachine added 6 commits July 18, 2026 12:45

Default the launcher appid to NT;RE's

e514b06

steam_appid.txt written by the launcher now identifies the mod without requiring -DNEO_MOD_APPID at configure time.

Add NEO_INSTALL_LAUNCHER to package the launcher

73c8cef

Follows the existing NEO_INSTALL_* install/CPack convention; produces a -launcher artifact holding the launcher binary for the install root. steam_api already ships with the engine binaries in bin/.

Terminate the executable path read from /proc/self/exe

31230ac

readlink does not NUL-terminate its buffer. The result feeds GetBaseDir, execv, and argv[0], so an unterminated path could carry stack garbage into every downstream path computation.

sunmachine mentioned this pull request Jul 18, 2026

Add NEO_INSTALL_ENGINE_BUNDLE, support for Linux and Windows #2026

Closed

3 tasks

Honor -wait_for_debugger in the Linux launcher

a508dad

The debugger-wait helpers existed but nothing called them, so the flag did nothing. Wait right after the bootstrap re-exec, before any Steam or engine work, so a debugger can attach to the process that loads the engine.

sunmachine marked this pull request as ready for review July 18, 2026 17:54

sunmachine changed the title ~~Fix silent SDK asset mounting failure in standalone Linux installs~~ Launch Linux and Windows through a launcher, with SDK dependency Jul 18, 2026

DESTROYGIRL requested review from a team and DESTROYGIRL and removed request for a team July 18, 2026 19:51

DESTROYGIRL requested changes Jul 18, 2026

View reviewed changes

Comment thread src/launcher_main/main.cpp

Comment thread src/launcher_main/CMakeLists.txt

Comment thread src/launcher_main/main.cpp

DESTROYGIRL added this to the Bug Cleanup milestone Jul 18, 2026

DESTROYGIRL added the Build System CMake and other build-related stuff label Jul 18, 2026

DESTROYGIRL added the Tournament Priority Issues to be prioritized for the upcoming NT;RE tournament label Jul 18, 2026

sunmachine added 3 commits July 18, 2026 20:08

Wrap launcher divergence from the SDK in NEO guards

62a126c

Let the engine surface the missing-SDK install flow

b91a9b9

Guard the launcher staging copies per-OS

c79f7a3

sunmachine requested a review from DESTROYGIRL July 19, 2026 01:15

Drop the stale Windows-flow warning

fa05a5a

DESTROYGIRL previously approved these changes Jul 19, 2026

View reviewed changes

DESTROYGIRL requested a review from a team July 19, 2026 12:56

sunmachine dismissed DESTROYGIRL’s stale review via d454beb July 19, 2026 14:42

sunmachine force-pushed the linux-build-fix branch from d454beb to fa05a5a Compare July 19, 2026 14:53

Masterkatze reviewed Jul 19, 2026

View reviewed changes

Comment thread src/launcher_main/CMakeLists.txt Outdated

Comment thread src/launcher_main/CMakeLists.txt Outdated

Comment thread src/CMakeLists.txt

sunmachine force-pushed the linux-build-fix branch from d454beb to fa05a5a Compare July 19, 2026 15:15

sunmachine added 2 commits July 19, 2026 11:25

Tidy launcher CMake indentation and paths

ccdf5d5

Scope the fopen guard to tier1 on Windows

a92d919

DESTROYGIRL previously approved these changes Jul 19, 2026

View reviewed changes

DESTROYGIRL requested a review from a team July 19, 2026 15:34

sunmachine dismissed DESTROYGIRL’s stale review via 4fa0e47 July 19, 2026 15:47

Build and upload the launcher package in CI

e2eb409

sunmachine force-pushed the linux-build-fix branch from 4fa0e47 to e2eb409 Compare July 19, 2026 15:50

Masterkatze previously approved these changes Jul 19, 2026

View reviewed changes

Split and ship the launcher debug information

c3ef868

sunmachine dismissed Masterkatze’s stale review via c3ef868 July 19, 2026 16:09

Derive split-debug names from target prefix and suffix

4e267dd

Masterkatze approved these changes Jul 19, 2026

View reviewed changes

DESTROYGIRL approved these changes Jul 19, 2026

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DESTROYGIRL merged commit 033fb35 into NeotokyoRebuild:master Jul 19, 2026
7 checks passed

sunmachine deleted the linux-build-fix branch July 19, 2026 22:12

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Launch Linux and Windows through a launcher, with SDK dependency#2019

Launch Linux and Windows through a launcher, with SDK dependency#2019
DESTROYGIRL merged 21 commits into
NeotokyoRebuild:masterfrom
sunmachine:linux-build-fix

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sunmachine commented Jul 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

Testing on Linux

Build (branch: linux-build-fix)

Overlay onto Steam (local testing only)

Depot Changes

Toolchain

Linked Issues

TODO

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sunmachine commented Jul 15, 2026

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