op-packages/gitbackup/files/etc/init.d/gitbackup

#!/bin/sh /etc/rc.common
# shellcheck shell=sh
# shellcheck disable=SC2034  # START/USE_PROCD/EXTRA_COMMANDS are read by rc.common, not this file
#
# gitbackup runs from cron, not as a daemon, so there is no process for
# start_service to supervise. This file's job is: (1) apply
# gitbackup.main.schedule to /etc/crontabs/root and make crond pick it up
# (reload_service, ticket 06), and (2) watch the packages actually in the
# backup set for config.change and turn a burst of edits into one debounced
# `gitbackup run` (service_triggers/config_change, spec R106/R107).
#
# GB_SHARE/GB_STATE_DIR/GB_BIN are overridable only so tests/run.sh can
# source this file directly (rc.common's own dispatch is not exercised by
# the unit tests -- see this file's own functions being called straight
# from a test body) against a tree, state directory and gitbackup binary
# that are not the router's real ones; the router never sets any of them.

GB_SHARE="${GB_SHARE:-/usr/share/gitbackup}"
GB_STATE_DIR="${GB_STATE_DIR:-/var/run/gitbackup}"
GB_BIN="${GB_BIN:-/usr/sbin/gitbackup}"

# shellcheck disable=SC1091  # GB_SHARE is a runtime path, not resolvable statically
. "$GB_SHARE/lib.sh"
# shellcheck disable=SC1091
. "$GB_SHARE/device.sh"
# shellcheck disable=SC1091
. "$GB_SHARE/schedule.sh"

START=60
USE_PROCD=1

# config_change is not one of rc.common's built-in actions (start/stop/
# reload/...); EXTRA_COMMANDS is rc.common's own mechanism for adding one
# (it appends this to ALL_COMMANDS right after sourcing this file -- see
# /etc/rc.common on the stand), which is what lets procd's run_script
# target `/etc/init.d/gitbackup config_change` actually dispatch anywhere.
EXTRA_COMMANDS="config_change"
EXTRA_HELP="	config_change	Internal: debounced trigger used by service_triggers, not for interactive use"

start_service() {
	reload_service
}

stop_service() {
	:
}

# reload_service -- (re)applies gitbackup.main.schedule/cron_expr to the
# crontab and makes crond pick it up. Runs on `/etc/init.d/gitbackup
# reload|restart|start` and, through procd_add_reload_trigger below,
# whenever gitbackup's own UCI config changes (e.g. a Settings save in
# LuCI) -- so flipping schedule from daily to weekly takes effect without a
# manual reload.
reload_service() {
	gb_cron_apply
}

# _gb_backed_up_packages -- private. The set of UCI packages the config-
# change trigger below watches: every /etc/config/<pkg> that is actually
# part of the backup set, per `sysupgrade -l` (spec: "список берётся из
# sysupgrade -l, фильтруется до /etc/config/*"), minus gitbackup's own
# config -- that one already gets procd_add_reload_trigger's ordinary
# `reload` below, which re-applies the schedule, not a debounced backup
# run; watching it a second time here would just fire both for the same
# edit.
_gb_backed_up_packages() {
	sysupgrade -l 2>/dev/null | sed -n 's#^/etc/config/##p' | sort -u | grep -v '^gitbackup$'
}

# config_change -- procd's run_script target for a backed-up package's
# config.change event, registered once per package in service_triggers
# below. Does not run a backup on the spot: a save in LuCI can touch
# several packages (e.g. network + firewall together) or the same one
# repeatedly, and each touch fires this again -- so this only (re)arms a
# single delayed `gitbackup run` after $debounce seconds, cancelling
# whatever the previous call armed first. A burst of edits therefore
# collapses into exactly one run (spec R106/R107), not one per edit.
#
# busybox ash's arithmetic (and `sleep`) only does whole seconds --
# `sleep 0.3` is "invalid number", measured on the stand -- hence the
# integer-only guard on $debounce below rather than trusting it unchecked.
#
# Killing the previous timer's PID only stops that subshell; if it had
# already progressed past `sleep` (a race that needs the previous debounce
# window to have fully elapsed a moment before this call, and is why a
# closer-together burst is exactly what this exists to collapse), the
# short-lived orphaned `sleep` left behind exits on its own and does
# nothing further -- rm and run only happen after it, in the same
# subshell, and that subshell is what got killed.
config_change() {
	_gb_debounce=$(gb_uci_get gitbackup.main.debounce 60)
	case "$_gb_debounce" in ''|*[!0-9]*) _gb_debounce=60 ;; esac

	mkdir -p "$GB_STATE_DIR"
	_gb_pidfile="$GB_STATE_DIR/debounce.pid"

	# Review finding, ticket 06: killing the PID from the pidfile blind is
	# fine right after this same router wrote it, but a long-uptime router
	# can wrap PIDs, and by the time the NEXT config.change fires that same
	# number may belong to an unrelated process this has no business
	# signaling. `kill -0` (send no signal, just ask whether the PID
	# exists) is the cheap half of that check -- it does not prove the PID
	# is still OUR sleep, only that it is not free for the kernel to have
	# reused by something else; reused PIDs are strictly the OS's own
	# concern here. Deliberately `kill -0`, not a `/proc/<pid>` test: this
	# file's own tests/run.sh unit test runs it on macOS, which has no
	# /proc at all, while `kill -0` is the one portable primitive both that
	# host and busybox ash on the router actually implement.
	if [ -f "$_gb_pidfile" ]; then
		_gb_prev_pid=$(cat "$_gb_pidfile")
		kill -0 "$_gb_prev_pid" 2>/dev/null && kill "$_gb_prev_pid" 2>/dev/null
	fi

	( sleep "$_gb_debounce"; rm -f "$_gb_pidfile"; "$GB_BIN" run --trigger procd >/dev/null 2>&1 ) &
	echo $! >"$_gb_pidfile"
}

service_triggers() {
	procd_add_reload_trigger "gitbackup"

	# R106/R107 both live under one on/off switch: a router that wants
	# gitbackup to run strictly on its own schedule can turn the
	# config-change trigger off without touching the watched packages.
	[ "$(gb_uci_get gitbackup.main.on_config_change 1)" = 1 ] || return 0

	# Same path resolution procd.sh's own _procd_add_reload_trigger uses
	# (readlink, falling back to $initscript itself when it is not a
	# symlink) -- $initscript is rc.common's own variable (set to "$1"
	# before this file is sourced, see /etc/rc.common on the stand), not
	# invented here; shellcheck cannot see that external assignment.
	# shellcheck disable=SC2154
	_gb_script=$(readlink "$initscript")
	_gb_name=$(basename "${_gb_script:-$initscript}")

	for _gb_pkg in $(_gb_backed_up_packages); do
		procd_add_config_trigger "config.change" "$_gb_pkg" /etc/init.d/"$_gb_name" config_change
	done
}