Drop doc/bootstrap.md, inaccurate and confusing to users

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
This commit is contained in:
Joachim Wiberg
2023-10-24 23:43:28 +02:00
parent d5738da307
commit eaef302420
3 changed files with 26 additions and 95 deletions
+1 -3
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@@ -3,7 +3,6 @@
* [Introduction](#introduction)
* [Features](#features)
* [Bootstrap](doc/bootstrap.md#bootstrap)
* [Runlevels](#runlevels)
* [Syntax](doc/config.md#syntax)
* [Runparts & /etc/rc.local](#runparts--etcrclocal)
@@ -391,8 +390,7 @@ Right after the runlevel change when all services have started properly,
No configuration stanza in `/etc/finit.conf` is required for `rc.local`.
If it exists and is an executable shell script Finit calls it at the very
end of the boot, before calling the `HOOK_SYSTEM_UP`. See more on hooks
in [doc/plugins.md](doc/plugins.md#hooks), and about the system bootstrap
in [doc/bootstrap.md](doc/bootstrap.md).
in [doc/plugins.md](doc/plugins.md#hooks).
### Limitations
-63
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@@ -1,63 +0,0 @@
Bootstrap
=========
0. Get bearings, disable kernel logs, initialize TTY and print banner,
unless `HOOK_BANNER` is defined, then call that instead
1. Prepare emergency shell, if enabled
2. Set up initial signal handlers
3. Set up default $PATH early
4. Mount `/proc` and `/sys`
5. Check kernel command line for `debug` to figure out log level
6. Load all `.so` plugins
7. Call `fsck` on file systems listed in `/etc/fstab`
8. Populate `/dev` using either udev or mdev, depending on system type
9. Parse `/etc/finit.conf`
10. Start built-in watchdog, if enabled and `WDT_DEVNODE` exists. This
means any WDT that requires a kernel module need to be either
compiled into the kernel, or insmod'ed in `/etc/finit.conf`
11. Load all `/etc/finit.d/*.conf` files and set hostname
12. Remount `/` read-write if `/` is listed in `/etc/fstab` without `ro`
13. Call 1st level hooks, `HOOK_ROOTFS_UP`
14. Mount all file systems listed in `/etc/fstab` and swap, if available.
Finit verifies that `/dev/shm`, `/dev/pts`, `/run`, and `/tmp` are
mounted. If not, Finit mounts them as `tmpfs` because otherwise the rest
of the boot may fail. On any mount error `HOOK_MOUNT_ERROR` is called.
After mount, regardless of error, `HOOK_MOUNT_POST` is called
15. Enable SysV init signals
16. Call 2nd level hooks, `HOOK_BASEFS_UP`
17. Cleanup stale files from `/tmp/*` et al and (re)create temporary files and
directories according to [tmpfiles.d(5)][], handled by `bootmisc` plugin
18. Load kernel params from `/etc/sysctl.d/*.conf`, `/etc/sysctl.conf`
et al. (Supports all locations that SysV init does.), handled by
`procps` plugin
19. Start all 'S' runlevel tasks and services
20. Bring up loopback interface and all `/etc/network/interfaces`, if
the `.conf` setting `network <SCRIPT>` is set, it is called instead
21. Call 3rd level hooks, `HOOK_NETWORK_UP`
22. If `runparts <DIR>` is set, [run-parts(8)][] is called on `<DIR>`
23. Switch to the configured runlevel from `/etc/finit.conf`, default 2.
At every runlevel change all `*.conf` files in `/etc/finit.d/` are
(re)loaded and new services, tasks, and blocking run commands are
started. Provided they are allowed in the new runlevel and all of
their conditions, if any, are set.
24. Call 4th level hooks, `HOOK_SVC_UP`
25. Call `/etc/rc.local`, if it exists and is an executable shell script
26. Call 5th level (last) hooks, `HOOK_SYSTEM_UP`
27. Start all configured TTYs
In (19) and (23) tasks and services defined in `/etc/finit.conf` and
`/etc/finit.d/*.conf` are started.
Notice the seven hook points that are called at various point in the
bootstrap process. This is where plugins can extend the boot in any
way they please. There are other hook points available, for more on
this, see [plugins.md](plugins.md).
For instance, at `HOOK_BASEFS_UP` a plugin could read an XML file from a
USB stick, convert/copy its contents to the system's `/etc/` directory,
well before all 'S' runlevel tasks are started. This could be used with
system images that are created read-only and all configuration is stored
on external media.
[run-parts(8)]: http://manpages.debian.org/cgi-bin/man.cgi?query=run-parts
[tmpfiles.d(5)]: https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html
+25 -29
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@@ -202,12 +202,13 @@ order, and `swapoff` is called.
- ` 0`: shutdown
Runlevels are declared per service/run/task/sysv command. Starting in
runlevel S ([bootStrap](bootstrap.md)), usually only for tasks supposed
to run once at boot, and services like `syslogd`, which you need to
start and run throughout the whole time your system is up. Before `S`
is started, however, Finit performs a lot of housekeeping tasks like
mounting all filesystems, calling `fsck` if needed, and making sure the
everything is OK.
runlevel S (bootStrap), usually only for tasks supposed to run once at
boot, and services like `syslogd`, which you need to start and run
throughout the whole time your system is up.
Before `S` is started, however, Finit performs a lot of housekeeping
tasks like mounting all filesystems, calling `fsck` if needed, and
making sure the everything is OK.
task [S] /lib/console-setup/console-setup.sh
service [S12345] env:-/etc/default/rsyslog rsyslogd -n $RSYSLOGD_ARGS
@@ -520,7 +521,7 @@ following directives:
> **Note:** not all directives are available in `/etc/finit.d/*.conf`
> and some directives are only available at [bootstrap][], runlevel `S`,
> and some directives are only available at bootstrap, runlevel `S`,
> see [Limitations](#limitations) below for details.
@@ -533,7 +534,7 @@ the contents of that file is used.
Deprecated. We recommend using `/etc/hostname` instead.
> **Note:** only read and executed in runlevel S ([bootstrap][]).
> **Note:** only read and executed in runlevel S (bootstrap).
### Kernel Modules
@@ -551,7 +552,7 @@ BusyBox mdev tool, add to `/etc/mdev.conf`:
$MODALIAS=.* root:root 0660 @modprobe -b "$MODALIAS"
> **Note:** only read and executed in runlevel S ([bootstrap][]).
> **Note:** only read and executed in runlevel S (bootstrap).
### Networking
@@ -564,7 +565,7 @@ Deprecated. We recommend using dedicated task/run stanzas per runlevel,
or `/etc/network/interfaces` if you have a system with `ifupdown`, like
Debian, Ubuntu, Linux Mint, or an embedded BusyBox system.
> **Note:** only read and executed in runlevel S ([bootstrap][]).
> **Note:** only read and executed in runlevel S (bootstrap).
### Alternate finit.d/
@@ -619,7 +620,7 @@ stanzas can share the same rlimits if they are in the same .conf.
**Syntax:** `runlevel <N>`
The system runlevel to go to after [bootstrap][] (S) has completed. `N`
The system runlevel to go to after bootstrap (S) has completed. `N`
is the runlevel number 0-9, where 6 is reserved for reboot and 0 for
halt.
@@ -628,7 +629,7 @@ Finit disables networking in this mode.
*Default:* 2
> **Note:** only read and executed in runlevel S ([bootstrap][]).
> **Note:** only read and executed in runlevel S (bootstrap).
### One-shot Commands (sequence)
@@ -966,9 +967,8 @@ previous stanza can also be written as:
**Syntax:** `runparts [progress] [sysv] <DIR>`
Call [run-parts(8)][] on `DIR` to run start scripts. All executable
files, or scripts, in the directory are called, in alphabetic order.
The scripts in this directory are executed at the very end of runlevel
`S`, [bootstrap][].
files in the directory are called, in alphabetic order. The scripts in
this directory are executed at the very end of runlevel `S`.
A common use-case for runparts scripts is to create and enable/disable
services, which Finit will then apply when changing runlevel from S to
@@ -993,10 +993,9 @@ before continuing. None of them can issue commands to start, stop, or
restart other services. Also, ensure all your services and programs
either terminate or start in the background or you will block Finit.
> **Note:** `runparts` scrips are only read and executed in runlevel S
> ([bootstrap][]). See [hook scripts](plugins.md#hooks) for other ways
> to run scripts at certain points during the complete lifetime of the
> system.
> **Note:** `runparts` scrips are only read and executed in runlevel S.
> See [hook scripts](plugins.md#hooks) for other ways to run scripts at
> certain points during the complete lifetime of the system.
**Recommendations:**
@@ -1109,8 +1108,8 @@ can be omitted to keep the kernel default.
tty [12345] @console noclear vt220
On really bare bones systems, or for board bringup, Finit can give you a
shell prompt as soon as [bootstrap][] is done, without opening any
device node:
shell prompt as soon as bootstrap is done, without opening any device
node:
tty [12345789] notty
@@ -1345,12 +1344,11 @@ Watchdog
When built `--with-watchdog` a separate service is built and installed
in `/libexec/finit/watchdogd`. If this exists at runtime, and the WDT
device node exists, Finit will start it and treat it as the elected
watchdog service to delegate its reboot to. See [bootstrap][] for
details. This delegation is to ensure that the system is rebooted by a
hardware watchdog timer -- on many embedded systems this is crucial to
ensure all circuits on the board are properly reset for the next boot,
in effect ensuring the system works the same after both a power-on and
reboot event.
watchdog service to delegate its reboot to. This delegation is to
ensure that the system is rebooted by a hardware watchdog timer -- on
many embedded systems this is crucial to ensure all circuits on the
board are properly reset for the next boot, in effect ensuring the
system works the same after both a power-on and reboot event.
The delegation is performed at the very last steps of system shutdown,
if reboot has been selected and an elected watchdog is known, first a
@@ -1372,8 +1370,6 @@ device descriptor. If the kernel driver has been built without this,
the only option is to remove `/libexec/finit/watchdogd` or build without
it at configure time.
[bootstrap]: bootstrap.md
keventd
-------