How to call Linux code from a Wine process - ArcaneNibble's site

But why?

There has been a longstanding shitpost that "Win32 is the stable Linux ABI". A huge amount of software (including/especially older games) designed for Windows works just as well (or sometimes better) on Linux when running via Wine/Proton. Meanwhile, the solutions for robustly packaging user-facing software for Linux continue to remain in flux with various technical issues that "someone" really ought to fix.

As a complementary solution to fixing Linux software distribution problems, suppose you want to enhance support for Linux for a program that is otherwise built for Windows. It turns out that Wine has some really useful mechanisms for this, but they're all poorly documented. I have gathered what is hopefully all of the useful and necessary information related to this all in one place.

Wine Is Not an Emulator

When running a Windows program under Wine on x86_64, both Windows code and Linux code exist in the same address space in a single process. You can see this by viewing /proc/xxx/maps for a Wine process:

$ cat /proc/138689/maps<br>7ff60000-7ffd8000 ---p 00000000 00:00 0<br>7ffd8000-7ffe0000 rw-p 00000000 00:00 0<br>7ffe0000-7ffe1000 r--s 00000000 00:01 176 /memfd:wine-mapping (deleted)<br>7ffe1000-7ffe2000 rw-p 00000000 00:00 0<br>7ffe2000-7fff0000 ---p 00000000 00:00 0<br>140000000-140001000 r--p 00000000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>140001000-140008000 r-xp 00001000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>140008000-140009000 rw-p 00008000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>140009000-14000d000 r--p 00009000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>14000d000-14000f000 rw-p 00000000 00:00 0<br>14000f000-140045000 r--p 0000d000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>140045000-140071000 rw-p 00000000 00:00 0<br>140071000-140072000 r--p 00043000 08:03 2259098 /usr/lib/wine/x86_64-windows/notepad.exe<br>55555755c000-5555578b9000 rw-p 00000000 00:00 0 [heap]<br>6ffffadb0000-6ffffadb1000 r--p 00000000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffadb1000-6ffffadc6000 r-xp 00001000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffadc6000-6ffffadc7000 rw-p 00016000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffadc7000-6ffffade3000 r--p 00017000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffade3000-6ffffade4000 rw-p 00000000 00:00 0<br>6ffffade4000-6ffffade9000 r--p 00033000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffade9000-6ffffae82000 rw-p 00000000 00:00 0<br>6ffffae82000-6ffffae83000 r--p 00038000 08:03 2259267 /usr/lib/wine/x86_64-windows/uxtheme.dll<br>6ffffaea0000-6ffffaea1000 r--p 00000000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffaea1000-6ffffaed0000 r-xp 00001000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffaed0000-6ffffaed1000 rw-p 00030000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffaed1000-6ffffaeee000 r--p 00031000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffaeee000-6ffffaeef000 rw-p 00000000 00:00 0<br>6ffffaeef000-6ffffafa3000 r--p 0004e000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffafa3000-6ffffb101000 rw-p 00000000 00:00 0<br>6ffffb101000-6ffffb102000 r--p 00102000 08:03 2257757 /usr/lib/wine/x86_64-windows/comdlg32.dll<br>6ffffb120000-6ffffb121000 r--p 00000000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb121000-6ffffb179000 r-xp 00001000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb179000-6ffffb17b000 rw-p 00059000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb17b000-6ffffb1af000 r--p 0005b000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb1af000-6ffffb1b0000 rw-p 00000000 00:00 0<br>6ffffb1b0000-6ffffb1df000 r--p 0008f000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb1df000-6ffffb538000 rw-p 00000000 00:00 0<br>6ffffb538000-6ffffb539000 r--p 000be000 08:03 2259113 /usr/lib/wine/x86_64-windows/ole32.dll<br>6ffffb890000-6ffffb891000 r--p 00000000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb891000-6ffffb892000 r-xp 00001000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb892000-6ffffb893000 rw-p 00002000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb893000-6ffffb897000 r--p 00003000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb897000-6ffffb898000 rw-p 00000000 00:00 0<br>6ffffb898000-6ffffb89b000 r--p 00007000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb89b000-6ffffb8a9000 rw-p 00000000 00:00 0<br>6ffffb8a9000-6ffffb8aa000 r--p 0000a000 08:03 2259023 /usr/lib/wine/x86_64-windows/msimg32.dll<br>6ffffb8c0000-6ffffb8c1000 r--p 00000000 08:03 2259355 /usr/lib/wine/x86_64-windows/winex11.drv<br>6ffffb8c1000-6ffffb8c2000 r-xp 00001000 08:03 2259355 /usr/lib/wine/x86_64-windows/winex11.drv<br>6ffffb8c2000-6ffffb8c3000 rw-p 00002000 08:03 2259355...