runtime: Add uevent queue state diagnostics

The uevent queue model now has several independent state directories:
pending queues, active event batches, delayed timers and paused queues.
Debugging boot delays from logs alone is difficult because these states
are intentionally separate.

Add ueventctl as a small read-only diagnostic tool that dumps the
current filesystem-backed queue state in a stable text format. Let it
use the same path variables as the runtime helpers and support --root so
tests and offline analysis can inspect an alternate initramfs state
tree.

Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>

Author: legionus

features/runtime/data/bin/ueventctl

@@ -0,0 +1,122 @@
+#!/bin/bash -efu
+
+srcdir="${0%/*}"
+
+. "$srcdir/uevent-sh-functions"
+
+root=
+command=dump
+
+usage()
+{
+	cat <<-EOF
+	Usage: ueventctl [--root DIR] [dump|queues|events|timers|pauses]
+	EOF
+}
+
+while [ "$#" -gt 0 ]; do
+	case "$1" in
+		--root)
+			shift
+			[ "$#" -gt 0 ] || {
+				usage >&2
+				exit 2
+			}
+			root="$1"
+			;;
+		--root=*)
+			root="${1#--root=}"
+			;;
+		-h|--help)
+			usage
+			exit 0
+			;;
+		dump|queues|events|timers|pauses)
+			command="$1"
+			;;
+		*)
+			usage >&2
+			exit 2
+			;;
+	esac
+	shift
+done
+
+root="${root%/}"
+[ "$root" != / ] ||
+	root=
+
+print_file()
+{
+	local file="$1" prefix="$2"
+
+	while IFS= read -r line || [ -n "$line" ]; do
+		printf '%s%s\n' "$prefix" "$line"
+	done < "$file"
+}
+
+print_state_tree()
+{
+	local title="$1" dir="$2" group groupdir item rel found=
+
+	printf '%s:\n' "$title"
+
+	if [ ! -d "$dir" ]; then
+		printf '  -\n'
+		return 0
+	fi
+
+	while IFS= read -r group; do
+		found=1
+		groupdir="$dir/$group"
+		printf '  %s\n' "$group"
+
+		while IFS= read -r item; do
+			rel="${item#$groupdir/}"
+			printf '    - /%s\n' "$rel"
+			print_file "$item" '      '
+		done < <(find "$groupdir" -mindepth 1 -type f ! -path '*/.tmp/*' -printf '%P\t%p\n' 2>/dev/null |
+			sort -k1,1 |
+			cut -f2-)
+	done < <(find "$dir" -mindepth 1 -maxdepth 1 -type d ! -name .tmp -printf '%f\n' 2>/dev/null |
+		sort)
+
+	[ -n "$found" ] ||
+		printf '  -\n'
+}
+
+show_queues()
+{
+	print_state_tree 'Queues' "$root$filterdir"
+}
+
+show_events()
+{
+	print_state_tree 'Events' "$root$ueventdir"
+}
+
+show_timers()
+{
+	print_state_tree 'Timers' "$root$timerdir"
+}
+
+show_pauses()
+{
+	print_state_tree 'Paused queues' "$root$uevent_confdb/queue/pause"
+}
+
+show_dump()
+{
+	show_queues
+	show_events
+	show_timers
+	show_pauses
+}
+
+case "$command" in
+	dump) show_dump ;;
+	queues) show_queues ;;
+	events) show_events ;;
+	timers) show_timers ;;
+	pauses) show_pauses ;;
+esac

testing/tests/ts0046-ueventctl-dump/expect

@@ -0,0 +1,17 @@
+Queues:
+  nvmf
+    - /fc.1
+      QUEUE=nvmf
+      TYPE=fc
+Events:
+  nvmf
+    - /done.fc.0
+      DONE=1
+Timers:
+  nvmf
+    - /42.retry.connect.1
+      TYPE=retry
+      NAME=connect
+Paused queues:
+  md-raid-member
+rc=0

testing/tests/ts0046-ueventctl-dump/run

@@ -0,0 +1,31 @@
+#!/bin/bash -efu
+
+cwd="${0%/*}"
+root="$cwd/root"
+
+rm -rf -- "$root"
+mkdir -p -- \
+	"$root/.initrd/uevent/queues/nvmf/.tmp" \
+	"$root/.initrd/uevent/events/nvmf" \
+	"$root/.initrd/uevent/timers/nvmf" \
+	"$root/.initrd/uevent/confdb/queue/pause/md-raid-member"
+
+export PATH="$PWD/.build/dest/usr/bin:$PATH"
+
+cat > "$root/.initrd/uevent/queues/nvmf/fc.1" <<'EOF'
+QUEUE=nvmf
+TYPE=fc
+EOF
+
+cat > "$root/.initrd/uevent/events/nvmf/done.fc.0" <<'EOF'
+DONE=1
+EOF
+
+cat > "$root/.initrd/uevent/timers/nvmf/42.retry.connect.1" <<'EOF'
+TYPE=retry
+NAME=connect
+EOF
+
+features/runtime/data/bin/ueventctl --root "$root" dump
+
+rm -rf -- "$root"