Joachim Wiberg
e8391864d7
Stanzas in /lib/finit/system cannot use if:keventd, or any other built-in service: if: is evaluated at parse time, and the generated .conf files for built-ins were read after the system directory, so the referenced service did not exist yet and the stanza was dropped. The late position was deliberate: it kept bundled services from starting before udev (5d703fd3). The motivating case was dbus, which has since moved to a build-time 20-dbus.conf (2e0b1d6f), and the built-ins that remain want the early slot: watchdogd should start as soon as possible, keventd is the device manager, and runparts is gated on int/bootstrap so its position never mattered. Reading /run/finit/system first also puts the override chain in its natural order: built-in/generated defaults, then bundled (read-only) system files in /lib, then the administrator (override) .conf file in /etc/finit.d, always read last. Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Introduction
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Reverse engineered from the EeePC fastinit
"gaps filled with frog DNA …"
— Claudio Matsuoka
Finit is a process starter and supervisor designed to run as PID 1 on Linux systems. It consists of a set of plugins and can be set up using configuration files. Plugins start at hook points and can run various set up tasks and/or install event handlers that later provide runtime services, e.g., PID file monitoring, or conditions.
Features
- Runlevels, defined per service
- One-shot tasks, services (daemons), or SysV init start/stop scripts
- Runparts and
/etc/rc.localsupport - Process supervision similar to systemd
- Fine-grained privilege control:
- Linux capabilities for minimal required privileges
- Supplementary groups for multi-group resource access
- Sourcing environment files
- Conditions for network/process/custom dependencies
- Readiness notification; PID files (native) for synchronizing system startup, support for systemd sd_notify(), or s6 style too
- Limited support for tmpfiles.d(5) (no aging, attributes, or subvolumes)
- Pre/Post script actions
- Rudimentary templating support
- Tooling to enable/disable services
- D-Bus API,
org.finitcontrol and signals for bus clients - Automatic reload of modified configuration files (optional)
- Built-in getty
- Built-in watchdog, with support for hand-over to watchdogd
- Built-in support for Debian/BusyBox
/etc/network/interfaces - Cgroups v2, both configuration and monitoring in
initctl top - Plugin support for customization
- Proper rescue mode with bundled
suloginfor protected maintenance shell - Switch root support for initramfs-to-real-root transitions
- Integration with watchdogd for full system supervision
- Logging to kernel ring buffer before
syslogdhas started, see the recommended sysklogd project for complete logging integration and how to log to the kernel ring buffer from scripts usinglogger
For a more thorough overview, see the Features section.
Tip
See SysV Init Compatibility for help to quickly get going with an existing SysV or BusyBox init setup.
Origin
This project is based on the original finit by Claudio Matsuoka which was reverse engineered from syscalls of the EeePC fastinit.
Finit is developed and maintained by Joachim Wiberg at GitHub. Please file bug reports, clone it, or send pull requests for bug fixes and proposed extensions.