Add capabilities at build

slopcap

@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+helper_dir=${SLOPTRAP_HELPER_DIR:-/run/sloptrap-helper}
+queue_dir="$helper_dir/queue"
+default_output=${SLOPTRAP_CAPTURE_DIR:-/codex/state/captures}
+mkdir -p "$queue_dir" "$default_output"
+
+if [[ ${1-} != "capture" ]]; then
+  printf 'usage: slopcap capture --interface <iface> [--filter <expr>] [--output <path>] [--stdout]\n' >&2
+  exit 2
+fi
+shift
+
+iface=""
+filter=""
+output=""
+stdout_mode=0
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --interface)
+      shift
+      [[ $# -gt 0 ]] || { printf 'slopcap: --interface requires a value\n' >&2; exit 2; }
+      iface=$1
+      ;;
+    --filter)
+      shift
+      [[ $# -gt 0 ]] || { printf 'slopcap: --filter requires a value\n' >&2; exit 2; }
+      filter=$1
+      ;;
+    --output)
+      shift
+      [[ $# -gt 0 ]] || { printf 'slopcap: --output requires a value\n' >&2; exit 2; }
+      output=$1
+      ;;
+    --stdout)
+      stdout_mode=1
+      ;;
+    *)
+      printf 'slopcap: unsupported argument %s\n' "$1" >&2
+      exit 2
+      ;;
+  esac
+  shift
+done
+
+[[ -n $iface ]] || { printf 'slopcap: --interface is required\n' >&2; exit 2; }
+if [[ -z $output && $stdout_mode -eq 0 ]]; then
+  output="$default_output/capture-$(date +%s).pcap"
+fi
+
+request_dir=$(mktemp -d "$queue_dir/request.XXXXXX.req")
+trap 'rm -rf "$request_dir"' EXIT INT TERM HUP
+printf 'packet-capture\n' >"$request_dir/op"
+printf '%s\n' "$iface" >"$request_dir/interface"
+printf '%s\n' "$filter" >"$request_dir/filter"
+printf '%s\n' "$output" >"$request_dir/output"
+printf '%s\n' "$stdout_mode" >"$request_dir/stdout_mode"
+
+stream_pid=""
+if [[ $stdout_mode -eq 1 ]]; then
+  touch "$request_dir/stdout"
+  tail -f "$request_dir/stdout" &
+  stream_pid=$!
+fi
+
+while [[ ! -f "$request_dir/status" ]]; do
+  sleep 1
+done
+
+if [[ -n $stream_pid ]]; then
+  kill "$stream_pid" >/dev/null 2>&1 || true
+  wait "$stream_pid" >/dev/null 2>&1 || true
+fi
+
+if [[ $stdout_mode -eq 0 && -s "$request_dir/stdout" ]]; then
+  cat "$request_dir/stdout"
+fi
+if [[ -s "$request_dir/stderr" ]]; then
+  cat "$request_dir/stderr" >&2
+fi
+
+status=$(<"$request_dir/status")
+exit "$status"