Remote debug ACAP application: Part 1 - build a gdbserver

[pataxis]

Important

This tutorial is replaced by remote-debug-example for AXIS OS versions 11.11 and later.

Introduction

This is a tutorial in three parts showing how-to remote debug an ACAP application on an Axis device from a user machine.

• Part 1 - build a gdbserver
• Part 2 - application with debug symbols
• Part 3
  • Part 3a - debug the application
  • Part 3b - debug using Visual Studio Code

The setup

• Axis device (target, remote)
  • Will run gdbserver and either attach to or start an installed ACAP application to debug
• User machine (desktop)
  • Will run gdb-multiarch and connect to the gdbserver on the device.
  • Needs access to the application binary with debug symbols (not stripped)

Limitations

• This tutorial requires root access on an Axis device and this solution will only work up until next AXIS OS LTS 2024. More information in this announcement.

Part 1 - build a gdbserver

This guide shows how to build a container image that contains a program called gdbserver which is part of GDB.

The gdbserver will run on the Axis device and is cross-compiled on a user machine (e.g. x86) to the target architecture of the Axis device to debug (aarch64, armv7hf) using the ACAP Native SDK.

Note
This guide use:

• GDB 9.2 and does not work for GDB >= 10
• ACAP Native SDK 1.9 and is compatible with AXIS OS 11.5 or later.
  • It has not been tested but building with an earlier SDK should be possible and be compatible with earlier AXIS OS versions.

The Dockerfile

Save the following Dockerfile to your desktop as Dockerfile.gdb9-2

ARG ARCH=armv7hf
ARG VERSION=1.9
ARG UBUNTU_VERSION=22.04
ARG REPO=axisecp
ARG SDK=acap-native-sdk
 
FROM ${REPO}/${SDK}:${VERSION}-${ARCH}-ubuntu${UBUNTU_VERSION}
 
# Build GDB server
ARG GDB_VERSION=9.2
ARG GDB_REPOSITORY=https://ftp.gnu.org/gnu/gdb
ARG GDB_ARCHIVE=gdb-${GDB_VERSION}.tar.gz
ARG GDB_BASE_DIR=/opt/build/gdb
ARG GDB_SOURCE_DIR=$GDB_BASE_DIR/src
ARG GDB_SERVER_CONF_DIR=$GDB_SOURCE_DIR/gdb/gdbserver
ARG GDB_BUILD_DIR=${GDB_BASE_DIR}/build
# The gdbserver will be installed to $GDB_INSTALL_DIR/bin/gdbserver
ARG GDB_INSTALL_DIR=${GDB_BASE_DIR}
ARG GDB_SERVER_BIN_DIR=${GDB_BASE_DIR}/bin
 
WORKDIR $GDB_BASE_DIR
RUN curl -sSL -O $GDB_REPOSITORY/$GDB_ARCHIVE
 
WORKDIR $GDB_SOURCE_DIR
RUN tar -xf $GDB_BASE_DIR/$GDB_ARCHIVE -C $GDB_SOURCE_DIR --strip-components=1
 
WORKDIR $GDB_BUILD_DIR
RUN . /opt/axis/acapsdk/environment-setup* && \
    $GDB_SERVER_CONF_DIR/configure \
      --host=$($CC -dumpmachine) \
      --prefix=${GDB_INSTALL_DIR} \
      --with-sysroot=${SDKTARGETSYSROOT}
 
RUN make && \
    make install
 
# Install ssh to scp gdbserver to device
RUN DEBIAN_FRONTEND=noninteractive \
    apt-get update && apt-get install -y -f --no-install-recommends \
    ssh \
    && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*
 
WORKDIR $GDB_SERVER_BIN_DIR

Build container image with gdbserver

In the same directory as you stored the Dockerfile, build the gdbserver for the architecture of your Axis device

docker buildx build . -f Dockerfile.gdb9-2 -t gdbserver9.2:1.9-armv7hf
docker buildx build . -f Dockerfile.gdb9-2 --build-arg ARCH=aarch64 -t gdbserver9.2:1.9-aarch64

Install gdbserver to Axis device

Note

• To copy the gdbserver program from user machine to Axis device, this example use scp and requires that SSH is enabled on the Axis device.
• To copy the gdbserver to /tmp on the Axis device with scp doesn't require root user.

docker run --rm -it gdbserver9.2:1.9-armv7hf
root@abcdef012345:/opt/build/gdb/bin# scp gdbserver root@192.168.0.90:/tmp

Next step

Continue to Part 2 - application with debug symbols