mirror of
https://github.com/troglobit/finit.git
synced 2026-10-02 14:02:52 +07:00
Joachim Wiberg
f0d7257374
A service that drops privileges cannot create its own PID file in /run, root owns it. Finit can create the file with pidfile-create, but the daemon still cannot touch it to confirm a SIGHUP. Five new settings, block format only: runtime-dir, state-dir, cache-dir, logs-dir, and config-dir. The value is a directory name, resolved under /run, /var/lib, /var/cache, /var/log, and /etc, respectively. The directory is created before the service starts, mode 0755 owned by user/group, and the full path is exported to the process as RUNTIME_DIRECTORY, STATE_DIRECTORY, CACHE_DIRECTORY, LOGS_DIRECTORY, and CONFIGURATION_DIRECTORY. Mode and ownership are asserted at creation only, a daemon may tighten them afterwards. The runtime directory is removed when the unit stops, after any exec-stop-post script, like systemd with RuntimeDirectoryPreserve=no. A completed run/task counts as stopped unless remain-after-exit keeps it up. The other four persist across restarts. These are the first settings with no legacy token: they are validated by service_set_dir() and stored on the svc that service_register() now returns. systemd accepts a list of directories per setting; this is a single name for now, widening later is compatible since libconfuse accepts a bare value for a list option. The test sysroot gains libnss_files.so.2, which ldd cannot see, glibc dlopen()s it. Without it getpwnam() fails inside the chroot, so user/group settings never resolved and directory ownership could not be tested. Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Introduction
{ align=right width=40% }
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
- 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.