fuzzer and performance optimisations

README.md

@@ -98,6 +98,21 @@ roadmap.
 Services run as `root` by default; `user`/`group` trigger a full privilege
 drop (supplementary groups, then gid, then uid) before exec.
 
+### imports
+
+Configs can be split across files with `@import PATH` (column 0, before any
+section in that file):
+
+```rc
+@import extra-services.rc
+```
+
+The path resolves relative to the importing file's directory (absolute paths
+pass through). A file reached by several imports is only parsed once;
+self/cyclic imports are reported as errors. Imported files may import other
+files and define services and actions like any other rc. `reload` re-parses
+the whole import tree, so imported changes take effect on `bctl reload`.
+
 ## control
 
 A running init listens on an abstract unix socket (`@bajia`). The bundled
@@ -150,3 +165,40 @@ policy with `checkpolicy`/`audit2allow`, then flip to `enforcing=1`.
 Limitations: uses the dynamic libselinux (no static build on Fedora), so the
 `--selinux` init is dynamically linked and the loader + libs (`libselinux`,
 `libpcre2-8`, glibc) are bundled into the initramfs.
+
+## development & testing
+
+Host-side unit tests (no framework, no dependencies) cover the rc parser, the
+`@import` machinery, and the pure supervisor helpers:
+
+```sh
+make test                       # builds build/unit_tests and runs it
+```
+
+The parser is also fuzz-tested with libFuzzer (needs clang):
+
+```sh
+python3 tools/fuzz.py --seconds 300
+```
+
+This drives random bytes through the same `parse_rc_stream` path the real init
+uses, with `@import` rejected so fuzz input can never open real files (e.g.
+`/dev/zero`). Crashes are saved under `build/fuzz-`; seeds accumulate in
+`build/fuzz-corpus` and grow between runs. A grammar dictionary (auto-seeded
+at `build/fuzz.dict`, overridable via `--dict`, disabled with `--no-dict`)
+guides coverage toward real rc keywords. Leak detection is on by default:
+`tools/lsan.supp` silences the spurious `strdup` that a torsocks `LD_PRELOAD`
+on the dev host allocates at startup, so any real leak in `parse_rc_stream` is
+saved as a `leak-*` artifact; pass `--no-detect-leaks` to disable it on a
+clean host. Peak fuzz RSS is driven mostly by ASan's freed-memory quarantine
+(256MiB default); fuzz.py pins it to 64MiB (`--quarantine-mb N`, 0 to
+disable), which roughly halves peak RSS.
+
+To leak-check the host-side unit tests under ASan/LSan instead:
+
+```sh
+make test-asan
+```
+
+(clang++ and a `leak:tsocks_once` suppression are used automatically; the
+default `make test` runs the same assertions without the sanitizer).