doc: update feature list

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

Author: troglobit

doc/features.md

@@ -1,6 +1,10 @@
 Finit Features
 ==============
 
+This page highlights some of Finit's key features with examples and usage
+scenarios. For complete documentation, configuration syntax, and advanced
+options, see the [Configuration](config/index.md) section.
+
 **Process Supervision**
 
 Start, monitor and restart services should they fail.
@@ -162,6 +166,28 @@ See the [Linux Capabilities](config/capabilities.md) section for detailed
 information, examples, and security best practices.
 
 
+**Supplementary Groups**
+
+Finit supports supplementary groups for services, allowing them to access
+resources owned by multiple groups without running as root. This complements
+capabilities for fine-grained privilege control.
+
+```conf
+service @caddy:caddy,ssl-cert /usr/bin/caddy run
+```
+
+In this example, the Caddy web server runs as user `caddy` with primary group
+`caddy`, but also has access to resources owned by the `ssl-cert` group (such
+as TLS certificates).
+
+Finit automatically reads the user's supplementary group membership from
+`/etc/group`. Additional groups can be specified explicitly using the syntax
+`@user:group,sup1,sup2,...`.
+
+See the [Non-privileged Services](config/services.md#non-privileged-services)
+section for more information.
+
+
 **Cgroups**
 
 Finit supports cgroups v2 and comes with the following default groups in
@@ -207,4 +233,59 @@ commands for details.
 > disabled early at boot.
 
 
+**Service Management**
+
+Finit includes the `initctl` tool for managing services and system state at
+runtime. Key capabilities include:
+
+- **Enable/Disable services**: Manage which services start at boot by moving
+  configuration files between `/etc/finit.d/available` and
+  `/etc/finit.d/enabled`
+- **Start/Stop/Restart**: Control individual services without requiring a
+  full system reboot
+- **Status monitoring**: View service state, PID, uptime, and resource usage
+- **Condition management**: Set and clear user-defined conditions to control
+  service dependencies
+- **Cgroup monitoring**: Real-time process and resource monitoring with
+  `initctl top`, similar to the traditional `top` command but cgroup-aware
+
+Example commands:
+
+```bash
+initctl enable myservice          # Enable service for next boot
+initctl start myservice           # Start service now
+initctl status                    # Show all services
+initctl top                       # Interactive resource monitor
+initctl cond set usr/custom       # Set custom condition
+```
+
+See the [Commands & Status](initctl.md) section for complete documentation.
+
+
+**Rescue Mode**
+
+Finit provides a built-in rescue mode for system recovery and maintenance.
+When booting with the `rescue` kernel parameter, the system enters a
+protected maintenance shell.
+
+If the bundled `sulogin` program is available (from Finit, util-linux, or
+BusyBox), you'll be prompted for the root password before accessing the
+maintenance shell. This provides secure access for system recovery.
+
+If `sulogin` is not available, Finit falls back to reading
+`/lib/finit/rescue.conf` and boots the system in a limited maintenance mode.
+
+```
+# Kernel command line
+linux /vmlinuz root=/dev/sda1 rescue
+```
+
+In rescue mode, `initctl` will not work. After fixing the problem, use
+`reboot -f` to force reboot.
+
+Rescue mode can be disabled at build time with `configure --without-rescue`.
+
+See the [Rescue Mode](config/rescue.md) section for more information.
+
+
 [5]: https://en.wikipedia.org/wiki/Runlevel

doc/index.md

@@ -1,7 +1,7 @@
 Introduction
 ============
 
-![Alpine screenshot](img/alpine-screenshot2.png){ align=right }
+![Alpine screenshot](img/alpine-screenshot2.png){ align=right width=40% }
 
 > Reverse engineered from the [EeePC fastinit][]  
 > "gaps filled with frog DNA …"  
@@ -17,26 +17,30 @@ PID file monitoring, or [conditions](conditions.md).
 Features
 --------
 
-  * [Runlevels][5], defined per service
-  * One-shot tasks, services (daemons), or [SysV init][4] start/stop scripts
-  * Runparts and `/etc/rc.local` support
+  * [Runlevels](config/runlevels.md), defined per service
+  * [One-shot tasks](config/task-and-run.md), [services](config/services.md) (daemons), or [SysV init][4] start/stop scripts
+  * [Runparts](config/runparts.md) and `/etc/rc.local` support
   * Process supervision similar to [systemd][]
-  * Sourcing environment files
-  * Conditions for network/process/custom dependencies
-  * Readiness notification; PID files (native) for synchronizing system
+  * Fine-grained privilege control:
+    - [Linux capabilities](config/capabilities.md) for minimal required privileges
+    - [Supplementary groups](config/services.md#non-privileged-services) for multi-group resource access
+  * [Sourcing environment files](config/service-env.md)
+  * [Conditions](conditions.md) for network/process/custom dependencies
+  * [Readiness notification](config/service-sync.md); 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
+  * [Pre/Post script actions](config/service-wrappers.md)
   * Rudimentary [templating support](config/templating.md)
-  * Tooling to enable/disable services
-  * Built-in getty
+  * [Tooling](initctl.md) to enable/disable services
+  * [Automatic reload](features.md#automatic-reload) of modified configuration files (optional)
+  * [Built-in getty](config/tty.md)
   * Built-in watchdog, with support for hand-over to [watchdogd][]
   * Built-in support for Debian/BusyBox [`/etc/network/interfaces`][3]
-  * Cgroups v2, both configuration and monitoring in `initctl top`
-  * Plugin support for customization
-  * Proper rescue mode with bundled `sulogin` for protected maintenance shell
+  * [Cgroups v2](config/cgroups.md), both configuration and monitoring in [`initctl top`](initctl.md)
+  * [Plugin support](plugins.md) for customization
+  * Proper [rescue mode](config/rescue.md) with bundled `sulogin` for protected maintenance shell
   * Integration with [watchdogd][] for full system supervision
-  * Logging to kernel ring buffer before `syslogd` has started, see the
+  * [Logging](config/logging.md) to kernel ring buffer before `syslogd` has started, see the
     recommended [sysklogd][] project for complete logging integration
 	and how to log to the kernel ring buffer from scripts using `logger`
 
@@ -64,6 +68,7 @@ and proposed extensions.
 [4]:                https://en.wikipedia.org/wiki/Init
 [5]:                https://en.wikipedia.org/wiki/Runlevel
 [6]:                https://github.com/finit-project/finit
+[dinit]:            https://davmac.org/projects/dinit/
 [systemd]:          https://www.freedesktop.org/wiki/Software/systemd/
 [sd_notify()]:      https://www.freedesktop.org/software/systemd/man/sd_notify.html
 [s6 style]:         https://skarnet.org/software/s6/notifywhenup.html