init.c

init.c is the init for The ENux Layer: a minimal C + x86_64 ASM static binary that runs as PID 1 on the ENux base system, brings the installed layers up, and hands off to the base's real init.

It is not a Bedrock init. Earlier revisions were a port of Bedrock Linux's shell init (pivot into a stratum, brl-enable every stratum in parallel, etcfs/crossfs, hijack install); all of that has been removed. The ENux Layer's model is simpler: a layer is a rootfs under /enux/layer/<name>, brought up by bind-mounting it onto itself and mounting /proc, /sys, /dev into it — the job of /enux/libexec/layer-enable.

What it does

main()
├── not PID 1?               → exec a backup init and bail
├── ensure_essential_env()   → mount /proc, /sys, /dev, /run, fuse
├── setup_term()             → reset the console, quit plymouth if present
├── print_logo()
├── load_init_config()       → read enux.conf: base layer + base init cmd
├── scan_layers()            → list /enux/layer/* (directories only)
├── enable_layers()          → fork /enux/libexec/layer-enable per
│                              non-base layer, in parallel, then reap
└── execv(<base init>)       → hand PID 1 to the base's real init

The base system is the running root; init.c never pivots into it or any other layer. Layers are entered on demand at runtime with layer enter.

Configuration

Read from /enux/etc/enux.conf:

[layers]
exec_order = enux,arch,fedora   # first entry is the base (never chrooted)

[init]
default = enux:/sbin/init       # the command after ':' is the base init

Both are optional: the base defaults to enux and the init to /sbin/init.

Design

• Statically linked — no libc.so dependency; safe before ld.so is set up.
• Direct syscalls — mount(2), open/read; no system()/popen().
• Parallel enable — all non-base layers are layer-enable'd at once via fork() + waitpid(-1); the slowest layer sets the wall clock.
• Never-die PID 1 — any failure before the final exec falls back to a backup init, then to an emergency shell.

Build

make            # build/init  (static ELF64, stripped)
make check      # verify ELF type, static linking, forbidden symbols, ASM
make debug      # build/init.debug with -g3 + ASan

The binary is consumed by The ENux Layer's own make (it copies build/init into /enux/sbin/init). See that repo's ISO.md for how it ships in an ISO.

License

GPL-2.0.