sys_resolver

Dynamic FHS-path resolution for ZainiumOS — no real /usr, /bin, /lib; real files live under /overlayer/syshub, /overlayer/syshub/x86_64-zainium-linux-musl, /overlayer/zexlib/union, /overlayer/zaisys.

No mount, no symlink, no kernel patch, no libc rebuild, no editing scripts/binaries.

Files

• src/remap.rs — scope guard (bin sbin lib usr opt var etc boot), path transform, 4-root probe.
• src/preload.rs — LD_PRELOAD interposition: open openat access faccessat stat lstat fstatat execve fopen dlopen.
• src/audit.rs, src/main.rs — sys-resolver doctor / sys-resolver resolve <path>.
• src/ffi.rs — C ABI export.

Not covered

• execl/execlp/execle/fopen64 — no distinct symbol or can't wrap on stable Rust.
• A prebuilt binary's PT_INTERP — read by the kernel before any userspace code runs.

Building

cargo test --release
cargo build --release --target x86_64-unknown-linux-musl --lib
/overlayer/syshub/x86_64-zainium-linux-musl/bin/gcc -shared \
  -o libsys_resolver.so \
  -Wl,--whole-archive target/x86_64-unknown-linux-musl/release/libsys_resolver.a -Wl,--no-whole-archive \
  -lpthread -ldl

Musl only — one .so can't serve musl and glibc at once, but there's no glibc on ZainiumOS today.

Deployed

• /overlayer/syshub/lib/libsys_resolver.so
• LD_PRELOAD=/overlayer/syshub/lib/libsys_resolver.so in oxidized-environment/oxienv.toml, oxienv.toml, environment.