Game bring-up: Forever Launcher (PPSA99030): past sendmsg with #7090; first-start Wine prefix setup stops

[milescoviello]

Status: on main, it aborts in sendmsg: control data is not supported. Its in-process Wine passes descriptors to and from its wineserver with SCM_RIGHTS. With #7090, the private wineserver starts, and Wine runs and shuts down in order. The launcher then stops on its own first-start prefix setup: "Setting up the Windows files did not finish."

Setup (runs reported in #7090)

• Title: Forever Launcher (PPSA99030; 01.000.012 in my gdb run, 01.000.021 in p3n1cillin's)
• babyhuey: Linux CI image with lavapipe, Ubuntu 24.04, GCC 13, Release, 60 s
• p3n1cillin: Ubuntu on WSL2, GCC 15.2.0, Release, llvmpipe on Xvfb, 120 s without input

The stop on main

• sendmsg: control data is not supported. Wine's first such call is sendmsg on a socket-pair end with MSG_NOSIGNAL | MSG_DONTWAIT. It carries one byte of data and a 24-byte control buffer holding one SOL_SOCKET/SCM_RIGHTS record (cmsg_len 20), which passes the end of another socket pair.

Next stop, with #7090

• The first-start prefix setup reports title wineboot skipped; prefix must be initialized by payload Wine and failed to open "C:\\windows\\system32\\wineboot.exe".
• Wine then exits with 0xC0000135 (a DLL not found).
• Not investigated yet.

Not possible on Windows: Wine needs 0x7ffe0000, which the host process already owns there (p3n1cillin).

Pull requests from this title

• feat(libkernel): pass descriptors in SCM_RIGHTS messages on Unix sockets #7090: SCM_RIGHTS control messages pass descriptors on guest Unix-domain sockets.

AI-assisted: yes (Claude Code)