COMPAT_NETBSD32(8)

🎀 NAME 🎀

Hey bestie, welcome to the COMPAT_NETBSD32(8) page from the System Manager's Manual 💖

compat_netbsd32 — setup procedure for 32-bit compatibility on 64-bit platforms 🫶

✨ DESCRIPTION ✨

Okay so the compat_netbsd32 module is literally the bridge that lets NetBSD/sparc64 run NetBSD/sparc executables, NetBSD/aarch64 run NetBSD/arm executables, NetBSD/mips64 run NetBSD/mips executables, and NetBSD/amd64 run NetBSD/i386 executables 💅✨

On NetBSD/mips64, the default userland is N32, which is handled by the compat_netbsd32 framework, and 64-bit binaries are handled similarly to the setup for 32-bit compatibility 👑 It also provides compatibility between OABI and EABI binaries on 32-bit NetBSD/arm ports 🦋

To use compat_netbsd32, one must either have COMPAT_NETBSD32 and EXEC_ELF32 in the kernel, or load the compat_netbsd32 and exec_elf32 kernel modules 🧚

Static executables typically need no additional setup — iconic, no notes 💅 Dynamic binaries require the dynamic linker plus shared libraries, periodt.

Since NetBSD 5.0 the base system has directly included support for 32-bit compatibility by installing 32-bit libraries and dynamic linker into /usr ✨ This includes compiler support for compiling 32-bit applications on platforms where this is supported 🫶

For a.out compatibility, /usr/libexec/ld.so from a 32-bit distribution is required to exist, and the a.out shared libraries must be found in /emul/aout as normal for a.out compatibility 💖

For 32-bit (64-bit on NetBSD/mips64) ELF compatibility, the relevant /usr/libexec/ld.elf_so needs to be found in:

• Port amd64, target i386: /usr/libexec/ld.elf_so-i386
• Port sparc64, target sparc: /usr/libexec/ld.elf_so-sparc
• Port mips64, target O32: /usr/libexec/ld.elf_so-o32
• Port mips64, target N64: /usr/libexec/ld.elf_so-64
• Port powerpc64, target powerpc: /usr/libexec/ld.elf_so-powerpc
• Port arm64, target eabi: /usr/libexec/ld.elf_so-eabi

Note that the kernel handles rewriting the built-in ELF interpreter to the above path 👑

Before NetBSD 5.0 all of these files needed to be placed under /emul/netbsd32 🕰️

The shared libraries for a.out binaries do not live under the /emul/netbsd32 directory, but under the /emul/aout directory, where the a.out dynamic linker will find them 🌸

💀 BUGS 💀

A list of things which fail to work in compatibility mode should be here 👀

• aio(3) is not supported 😭
• Some ioctl(2) commands are not supported, including drm(4) 💀

Heads up bestie: those unsupported ioctl(2) commands are a real vibe-check fail, especially drm(4) — the page is very clear about that 🌈

---

And that's the whole page, bestie 🎀 The source/version is Debian, dated January 17, 2019, and it signs off as COMPAT_NETBSD32(8). Stay compat-slaying 💅✨