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The README and the crate CLAUDE.md both described the C/Rust split, the platform matrix, and the intercepted functions, and the CLAUDE.md even restated platform details it told the reader to get from the README. Make the README the single source for the descriptive facts (migrating up the BSD rows and symbol-visibility column it was missing), and trim CLAUDE.md to the agent-only constraints plus the don't-merge directive that points at the README for the why. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
1.7 KiB
1.7 KiB
Dynamic library for Bear interception
This crate provides a dynamic library for Unix systems that can be used with Bear for intercepting system calls via the LD_PRELOAD mechanism (or DYLD_INSERT_LIBRARIES on macOS).
Overview
libexec is designed to work with the Bear compilation database generator. It intercepts system calls like execve to track command execution during builds.
The library is split into a C shim (src/c/shim.c) and Rust implementation (src/implementation.rs). This separation exists because:
- Stable Rust cannot handle C variadic arguments (
execlfamily) - On FreeBSD, libc functions may call each other internally — having all exported symbols in C call into Rust (which uses
dlsym(RTLD_NEXT, ...)) avoids recursive interception issues
Supported Platforms
| Platform | Mechanism | Symbol visibility |
|---|---|---|
| Linux, FreeBSD, OpenBSD, NetBSD, DragonFly BSD | LD_PRELOAD |
ELF version scripts |
| macOS | DYLD_INSERT_LIBRARIES |
-exported_symbols_list |
On unsupported platforms (e.g. Windows), the build displays a warning and skips library generation.
Features
- Intercepts
execfamily calls,posix_spawn,popen, andsystem - Automatically "doctors" child process environments to maintain interception across
execcalls - Reports intercepted executions to a TCP collector
- Platform capability detection at build time (only intercepts functions available on the host)
Building
To build libexec in debug mode:
cargo build -p intercept-preload
For the release version:
cargo build -p intercept-preload --release
The resulting shared library will be in target/debug/libexec.so (or .dylib on macOS) and target/release/libexec.so respectively.