Each SNMP GET/WALK now runs in a forked child process. If libnetsnmp
triggers a SIGSEGV or other fatal signal, only the child dies - the
parent agent logs the crash and continues operating for all other devices.
Key changes:
- C helper: snmp_get_isolated() and snmp_walk_isolated() using
fork+pipe pattern with 60s alarm watchdog and mutex-serialized forks
- Rust: IsolationMode enum (Fork/Direct) controlled by
TOWEROPS_SNMP_ISOLATION env var, defaults to Fork
- New CrashRecovered error variant with signal info and logging
- Device poller logs crash recovery events at error level
- Startup logs active isolation mode
Set TOWEROPS_SNMP_ISOLATION=direct to disable isolation for debugging.
Both ring and aws-lc-rs were enabled transitively (webpki-roots enables
rustls default features), causing rustls to panic at runtime because it
couldn't auto-detect which crypto provider to use.
- Add rustls as direct dep with ring only, disable default features
- Switch russh from aws-lc-rs (default) to ring crypto backend
- Call ring::default_provider().install_default() at startup
- Add macOS build fix: detect Homebrew OpenSSL path for netsnmp's libcrypto
The agent version was always showing 0.1.0 because build.rs tried to
run 'git describe' inside the Docker build, but .git directory wasn't
copied into the image.
Changes:
- Add VERSION build arg to Dockerfile
- Pass VERSION as env var to cargo build commands
- Update GitLab CI to pass --build-arg VERSION
- Modify build.rs to prefer BUILD_VERSION env var over git commands
This ensures the version displayed by the agent matches the Docker
image tag it was built with.
