#!/bin/bash
# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Run, inspect and debug
### run the debug agent on target and connect to it with zxdb

## Starts the debug agent on the proposed target and automatically connect zxdb
## to it. Will close the debug agent on exit.
##
## TROUBLESHOOTING TIPS:
##
## - Remember to use "fx set-device" when working with multiple devices.
## - This scripts by default will mute the SSH connection stdout/stderr, so any
##   errors triggered by it won't appear. Use the --verbose-agent flag to see
##   the output.
## - This scripts uses the tool "nc" for testing TCP connections. Check that it
##   is in $PATH and that it works.
##
## Usage: fx debug [(--core|-c) <CORE>] [--no-agent] [(--port|-p) <PORT>]
##                 [--unwind=(aosp|ng)] [(--verbose-agent|-va)]
##
##    --core            Load a minidump file into zxdb.
##    --no-agent        Don't start a Debug Agent.
##    --port            Port the debug agent will be listening on.
##                      Will use 2345 by default.
##    --target-core     Look on the target for a minidump file taken by
##                      crashpad, download it and load it into zxdb.
##    --unwind          Choose the unwinder to use. Options are "ng" for "ngunwind" (Fuchsia's
##                      fork of libunwind), or "aosp" (Android's unwinder). Defaults to "ng".
##    --verbose-agent   Whether the debug agent's stdout/stderr should be shown.
##                      Useful for debugging the debugger. Yo' dawg.
##
## Flags after -- are parsed by zxdb.  See zxdb's documentation for more
## details.

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/../lib/vars.sh || exit $?
fx-config-read
source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/../contrib/lib/debug-agent.sh || exit $?

# Defaults.
port=
core=
unwind_flag=
agent_out="/dev/null"
no_agent=
target_core=

# Flag parsing.
while [[ $# -gt 0 ]]; do
  case "$1" in
    --help|-h)
      fx-command-help
      exit 0
      ;;
    --no-agent)
      no_agent=true
      ;;
    --port|-p)
      shift
      port="$1"
      ;;
    --port=*)
      port="${1:7}"
      ;;
    --verbose-agent|-va)
      agent_out="/dev/stdout"
      ;;
    --core|-c)
      arg=$1
      shift
      core="$1"
      if [[ -z "${core}" ]]; then
        echo "${arg} takes an argument"
        exit 1
      fi
      no_agent=true
      ;;
    --core=*)
      core="${1:7}"
      no_agent=true
      ;;
    --target-core)
      target_core=true
      no_agent=true
      ;;
    --unwind)
      shift
      unwind_flag="--unwind=$1"
      ;;
    --unwind=*)
      unwind_flag="--unwind=${1:9}"
      ;;
    --)
      shift
      break # Remaining flags are passed to zxdb
      ;;
    *)
      echo "Invalid flag $1"
      exit 1
  esac
  shift
done

if [[ -n "${port}" && -n "${core}" ]]; then
  echo "Specifying both a port and a core doesn't make sense"
  exit 1
fi

if [[ -n "${target_core}" && -n "${core}" ]]; then
  echo "Cannot specify a core file when fetching a core from the target"
  exit 1;
fi

if [[ -n "${port}" && -n "${target_core}" ]]; then
  echo "Cannot specify a port file when fetching a core from the target"
  exit 1
fi

if [[ -z "${port}" ]]; then
  port=2345
fi

if [[ -n "${target_core}" ]]; then
  crashpad_agent_dir=`fx-command-run shell ls /tmp/r/sys | grep crashpad_agent`
  if [[ -z "${crashpad_agent_dir}" ]]; then
    fx-error "Could not find crashpad agent directory"
    exit 1
  fi

  core_name=`fx-command-run shell \
    ls "/tmp/r/sys/${crashpad_agent_dir}/crashes/completed" | grep -v meta`

  if [[ -z "${core_name}" ]]; then
    fx-error "No cores available on device"
    exit 1
  fi

  if [[ "$(echo "${core_name}" | wc -l)" -ge 2 ]]; then
    echo "Which core would you like to analyze?"
    select choice in ${core_name}; do
      core_name=${choice}
      break
    done
  fi

  core="/tmp/zxdb_fetched_core.dmp"
  fx-command-run "cp" "--to-host" \
    "/tmp/r/sys/${crashpad_agent_dir}/crashes/completed/${core_name}" \
    "${core}"
fi

if [[ -n "${core}" && ! -f "${core}" ]]; then
  echo "Cannot find file ${core}"
  exit 1
fi

connect_ops=()

if [[ ! -z "${core}" ]]; then
  connect_ops=("--core" "${core}")
elif [[ ! -z "${no_agent}" ]]; then
  echo "Not starting a debug agent."
else
  if launch_debug_agent "${port}" "${unwind_flag}" "${agent_out}"; then
    connect_ops=("--connect" "$(get-device-addr-resource):${port}")
  else
    fx-error "Could not launch debug agent. Exiting. Make sure you're running 'fx serve'."
    exit 1
  fi
fi

# We start the client with the flag that tells it to quit the agent when zxdb quits.
"${FUCHSIA_BUILD_DIR}/host-tools/zxdb" \
  ${connect_ops[@]} \
  "--quit-agent-on-exit" \
  "-b" "${FUCHSIA_BUILD_DIR}" \
  "-s" "${FUCHSIA_BUILD_DIR}" \
  "-s" "${ZIRCON_BUILDROOT}" \
  "-s" "${PREBUILT_CLANG_DIR}/lib/debug" \
  "--symbol-cache" ~ \
  "--symbol-server" "gs://fuchsia-artifacts-release/debug" \
  "$@"

# launch_debug_agent starts the agent in a subprocess, which zxdb will
# terminate by --quit-agent-on-exit, we want to wait that process however.
wait