qubes-doc/developer/building/development-workflow.rst

====================
Development workflow
====================


A workflow for developing Qubes OS+

First things first, setup :doc:`QubesBuilder </developer/building/qubes-builder>`. This
guide assumes you’re using qubes-builder to build Qubes.

Repositories and committing Code
--------------------------------


Qubes is split into a bunch of git repos. These are all contained in the
``qubes-src`` directory under qubes-builder. Subdirectories there are
separate components, stored in separate git repositories.

The best way to write and contribute code is to create a git repo
somewhere (e.g., github) for the repo you are interested in editing
(e.g., ``qubes-manager``, ``core-agent-linux``, etc). To integrate your
repo with the rest of Qubes, cd to the repo directory and add your
repository as a remote in git

**Example:**

.. code:: bash

      $ cd qubes-builder/qubes-src/qubes-manager
      $ git remote add abel git@github.com:abeluck/qubes-manager.git



You can then proceed to easily develop in your own branches, pull in new
commits from the dev branches, merge them, and eventually push to your
own repo on github.

When you are ready to submit your changes to Qubes to be merged, push
your changes, then create a signed git tag (using ``git tag -s``).
Finally, send a letter to the Qubes listserv describing the changes and
including the link to your repository. You can also create pull request
on github. Don’t forget to include your public PGP key you use to sign
your tags.

Kernel-specific notes
^^^^^^^^^^^^^^^^^^^^^


Prepare fresh version of kernel sources, with Qubes-specific patches applied
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


In qubes-builder/qubes-src/linux-kernel:

.. code:: bash

      make prep



The resulting tree will be in kernel-<VERSION>/linux-<VERSION>:

.. code:: bash

      ls -ltrd kernel*/linux*



.. code:: bash

      drwxr-xr-x 23 user user 4096 Nov  5 09:50 kernel-3.4.18/linux-3.4.18
      drwxr-xr-x  6 user user 4096 Nov 21 20:48 kernel-3.4.18/linux-obj



Go to the kernel tree and update the version
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


In qubes-builder/qubes-src/linux-kernel:

.. code:: bash

      cd kernel-3.4.18/linux-3.4.18



Changing the config
^^^^^^^^^^^^^^^^^^^


In kernel-3.4.18/linux-3.4.18:

.. code:: bash

      cp ../../config .config
      make oldconfig



Now change the configuration. For example, in
kernel-3.4.18/linux-3.4.18:

.. code:: bash

      make menuconfig



Copy the modified config back into the kernel tree:

.. code:: bash

      cp .config ../../../config



Patching the code
^^^^^^^^^^^^^^^^^


TODO: describe the workflow for patching the code, below are some random
notes, not working well

.. code:: bash

      ln -s ../../patches.xen
      export QUILT_PATCHES=patches.xen
      export QUILT_REFRESH_ARGS="-p ab --no-timestamps --no-index"
      export QUILT_SERIES=../../series-pvops.conf
      
      quilt new patches.xen/pvops-3.4-0101-usb-xen-pvusb-driver-bugfix.patch
      quilt add drivers/usb/host/Kconfig drivers/usb/host/Makefile \
              drivers/usb/host/xen-usbback/* drivers/usb/host/xen-usbfront.c \
              include/xen/interface/io/usbif.h
      
      *edit something*
      
      quilt refresh
      cd ../..
      vi series.conf



Building RPMs
^^^^^^^^^^^^^


TODO: Is this step generic for all subsystems?

Now it is a good moment to make sure you have changed kernel release
name in rel file. For example, if you change it to ‘1debug201211116c’
the resulting RPMs will be named
‘kernel-3.4.18-1debug20121116c.pvops.qubes.x86_64.rpm’. This will help
distinguish between different versions of the same package.

You might want to take a moment here to review (git diff, git status),
commit your changes locally.

To actually build RPMs, in qubes-builder:

.. code:: bash

      make linux-kernel



RPMs will appear in qubes-src/linux-kernel/pkgs/fc20/x86_64:

.. code:: bash

      -rw-rw-r-- 1 user user 42996126 Nov 17 04:08 kernel-3.4.18-1debug20121116c.pvops.qubes.x86_64.rpm
      -rw-rw-r-- 1 user user 43001450 Nov 17 05:36 kernel-3.4.18-1debug20121117a.pvops.qubes.x86_64.rpm
      -rw-rw-r-- 1 user user  8940138 Nov 17 04:08 kernel-devel-3.4.18-1debug20121116c.pvops.qubes.x86_64.rpm
      -rw-rw-r-- 1 user user  8937818 Nov 17 05:36 kernel-devel-3.4.18-1debug20121117a.pvops.qubes.x86_64.rpm
      -rw-rw-r-- 1 user user 54490741 Nov 17 04:08 kernel-qubes-vm-3.4.18-1debug20121116c.pvops.qubes.x86_64.rpm
      -rw-rw-r-- 1 user user 54502117 Nov 17 05:37 kernel-qubes-vm-3.4.18-1debug20121117a.pvops.qubes.x86_64.rpm



Useful :doc:`QubesBuilder </developer/building/qubes-builder>` commands
^^^^^^^^^^^^^^^^^^^^^^^^^^^^


1. ``make check`` - will check if all the code was committed into
   repository and if all repository are tagged with signed tag.

2. ``make show-vtags`` - show version of each component (based on git
   tags) - mostly useful just before building ISO. **Note:** this will
   not show version for components containing changes since last version
   tag.

3. ``make push`` - push change from **all** repositories to git server.
   You must set proper remotes (see above) for all repositories first.

4. ``make prepare-merge`` - fetch changes from remote repositories (can
   be specified on commandline via GIT_SUBDIR or GIT_REMOTE vars),
   (optionally) verify tags and show the changes. This do not merge the
   changes - there are left for review as FETCH_HEAD ref. You can merge
   them using ``git merge FETCH_HEAD`` (in each repo directory). Or
   ``make do-merge`` to merge all of them.



Copying Code to dom0
--------------------


When developing it is convenient to be able to rapidly test changes.
Assuming you’re developing Qubes on Qubes, you should be working in a
special VM for Qubes and occasionally you will want to transfer code or
RPMs back to dom0 for testing.

Here are some handy scripts Marek has shared to facilitate this.

You may also like to run your :doc:`test environment on separate machine </developer/debugging/test-bench>`.

Syncing dom0 files
^^^^^^^^^^^^^^^^^^


TODO: edit this script to be more generic

.. code:: bash

      #!/bin/sh
      
      set -x
      set -e
      
      QUBES_PY_DIR=/usr/lib64/python2.6/site-packages/qubes
      QUBES_PY=$QUBES_PY_DIR/qubes.py
      QUBESUTILS_PY=$QUBES_PY_DIR/qubesutils.py
      
      qvm-run -p qubes-devel 'cd qubes-builder/qubes-src/core/dom0; tar c qmemman/qmemman*.py qvm-core/*.py qvm-tools/* misc/vm-template-hvm.conf misc/qubes-start.desktop ../misc/block-snapshot aux-tools ../qrexec' |tar xv
      cp $QUBES_PY qubes.py.bak$$
      cp $QUBESUTILS_PY qubesutils.py.bak$$
      cp /etc/xen/scripts/block-snapshot block-snapshot.bak$$
      sudo cp qvm-core/qubes.py $QUBES_PY
      sudo cp qvm-core/qubesutils.py $QUBESUTILS_PY
      sudo cp qvm-core/guihelpers.py $QUBES_PY_DIR/
      sudo cp qmemman/qmemman*.py $QUBES_PY_DIR/
      sudo cp misc/vm-template-hvm.conf /usr/share/qubes/
      sudo cp misc/qubes-start.desktop /usr/share/qubes/
      sudo cp misc/block-snapshot /etc/xen/scripts/
      sudo cp aux-tools/qubes-dom0-updates.cron /etc/cron.daily/
      # FIXME(Abel Luck): I hope to



Apply qvm-tools
^^^^^^^^^^^^^^^


TODO: make it more generic

.. code:: bash

      #!/bin/sh
      
      BAK=qvm-tools.bak$$
      mkdir -p $BAK
      cp -a /usr/bin/qvm-* /usr/bin/qubes-* $BAK/
      sudo cp qvm-tools/qvm-* qvm-tools/qubes-* /usr/bin/



Copy from dom0 to an appvm
^^^^^^^^^^^^^^^^^^^^^^^^^^


.. code:: bash

      #/bin/sh
      #
      # usage ./cp-domain <vm_name> <file_to_copy>
      #
      domain=$1
      file=$2
      fname=`basename $file`
      
      qvm-run $domain 'mkdir /home/user/incoming/dom0 -p'
      cat $file| qvm-run --pass-io $domain "cat > /home/user/incoming/dom0/$fname"



Git connection between VMs
--------------------------


Sometimes it’s useful to transfer git commits between VMs. You can use
``git format-patch`` for that and simply copy the files. But you can
also setup custom qrexec service for it.

Below example assumes that you use ``builder-RX`` directory in target VM
to store sources in qubes-builder layout (where ``X`` is some number).
Make sure that all the scripts are executable.

Service file (save in ``/usr/local/etc/qubes-rpc/local.Git`` in target
VM):

.. code:: bash

      #!/bin/sh
      
      exec 2>/tmp/log2
      
      read service rel repo
      echo "Params: $service $rel $repo" >&2
      # Adjust regexps if needed
      echo "$repo" | grep -q '^[A-Za-z0-9-]\+$' || exit 1
      echo "$rel" | grep -q '^[0-9.]\+$' || exit 1
      path="/home/user/builder-R$rel/qubes-src/$repo"
      if [ "$repo" = "builder" ]; then
          path="/home/user/builder-R$rel"
      fi
      case $service in
          git-receive-pack|git-upload-pack)
              echo "starting $service $path" >&2
              exec $service $path
              ;;
          *)
              echo "Unsupported service: $service" >&2
              ;;
      esac



Client script (save in ``~/bin/git-qrexec`` in source VM):

.. code:: bash

      #!/bin/sh
      
      VMNAME=$1
      
      (echo $GIT_EXT_SERVICE $2 $3; exec cat) | qrexec-client-vm $VMNAME local.Git



You will also need to setup qrexec policy in dom0
(``/etc/qubes-rpc/policy/local.Git``).

Usage:

.. code:: bash

      [user@source core-agent-linux]$ git remote add testbuilder "ext::git-qrexec testbuilder 3 core-agent-linux"
      [user@source core-agent-linux]$ git push testbuilder master



You can create ``~/bin/add-remote`` script to ease adding remotes:

.. code:: bash

      #!/bin/sh
      
      [ -n "$1" ] || exit 1
      
      if [ "$1" = "tb" ]; then
          git remote add $1 "ext::git-qrexec testbuilder 3 `basename $PWD`"
          exit $?
      fi
      
      git remote add $1 git@github.com:$1/qubes-`basename $PWD`



It should be executed from component top level directory. This script
takes one argument - remote name. If it is ``tb``, then it creates
qrexec-based git remote to ``testbuilder`` VM. Otherwise it creates
remote pointing at github account of the same name. In any case it
points at repository matching current directory name.

Sending packages to different VM
--------------------------------


Other useful script(s) can be used to setup local package repository
hosted in some VM. This way you can keep your development VM behind
firewall, while having an option to expose some yum/apt repository to
the local network (to have them installed on test machine).

To achieve this goal, a dummy repository can be created, which instead
of populating metadata locally, will upload the packages to some other
VM and trigger repository update there (using qrexec). You can use
``unstable`` repository flavor, because there is no release managing
rules bundled (unlike current and current-testing).

RPM packages - yum repo
^^^^^^^^^^^^^^^^^^^^^^^


In source VM, grab
`linux-yum <https://github.com/QubesOS/qubes-linux-yum>`__ repository
(below is assumed you’ve made it in ``~/repo-yum-upload`` directory) and
replace ``update_repo.sh`` script with:

.. code:: bash

      #!/bin/sh
      
      VMNAME=repo-vm
      
      set -e
      qvm-copy-to-vm $VMNAME $1
      # remove only files, leave directory structure
      find -type f -name '*.rpm' -delete
      # trigger repo update
      qrexec-client-vm $VMNAME local.UpdateYum



In target VM, setup actual yum repository (also based on
`linux-yum <https://github.com/QubesOS/qubes-linux-yum>`__, this time
without modifications). You will also need to setup some gpg key for
signing packages (it is possible to force yum to install unsigned
packages, but it isn’t possible for ``qubes-dom0-update`` tool). Fill
``~/.rpmmacros`` with key description:

.. code:: bash

      %_gpg_name Test packages signing key



Then setup ``local.UpdateYum`` qrexec service
(``/usr/local/etc/qubes-rpc/local.UpdateYum``):

.. code:: bash

      #!/bin/sh
      
      if [ -z "$QREXEC_REMOTE_DOMAIN" ]; then
          exit 1
      fi
      
      real_repository=/home/user/linux-yum
      incoming=/home/user/QubesIncoming/$QREXEC_REMOTE_DOMAIN
      
      find $incoming -name '*.rpm' |xargs rpm -K |grep -iv pgp |cut -f1 -d: |xargs -r setsid -w rpm --addsign 2>&1
      
      rsync -lr --remove-source-files $incoming/ $real_repository
      cd $real_repository
      export SKIP_REPO_CHECK=1
      if [ -d $incoming/r3.1 ]; then
          ./update_repo-unstable.sh r3.1
      fi
      
      if [ -d $incoming/r3.0 ]; then
          ./update_repo-unstable.sh r3.0
      fi
      
      if [ -d $incoming/r2 ]; then
          ./update_repo-unstable.sh r2
      fi
      find $incoming -type d -empty -delete
      exit 0



Of course you will also need to setup qrexec policy in dom0
``/etc/qubes-rpc/policy/local.UpdateYum``.

If you want to access the repository from network, you need to setup
HTTP server serving it, and configure the system to let other machines
actually reach this HTTP server. You can use for example using :ref:`port forwarding <user/security-in-qubes/firewall:port forwarding to a qube from the outside world>`
or setting up Tor hidden service. Configuration details of those
services are outside of the scope of this page.

Usage: setup ``builder.conf`` in source VM to use your dummy-uploader
repository:

.. code:: bash

      LINUX_REPO_BASEDIR = ../../repo-yum-upload/r3.1



Then use ``make update-repo-unstable`` to upload the packages. You can
also specify selected components on command line, then build them and
upload to the repository:

.. code:: bash

      make COMPONENTS="core-agent-linux gui-agent-linux linux-utils" qubes update-repo-unstable



On the test machine, add yum repository (``/etc/yum.repos.d``) pointing
at just configured HTTP server. For example:

.. code:: bash

      [local-test]
      name=Test
      baseurl=http://local-test.lan/linux-yum/r$releasever/unstable/dom0/fc20



Remember to also import gpg public key using ``rpm --import``.

Deb packages - Apt repo
^^^^^^^^^^^^^^^^^^^^^^^


Steps are mostly the same as in the case of yum repo. The only details
that differ:

- use `linux-deb <https://github.com/QubesOS/qubes-linux-deb>`__
  instead of `linux-yum <https://github.com/QubesOS/qubes-linux-yum>`__
  as a base - both in source and target VM

- use different ``update_repo.sh`` script in source VM (below)

- use ``local.UpdateApt`` qrexec service in target VM (code below)

- in target VM additionally place ``update-local-repo.sh`` script in
  repository dir (code below)



``update_repo.sh`` script:

.. code:: bash

      #!/bin/sh
      
      set -e
      
      current_release=$1
      VMNAME=repo-vm
      
      qvm-copy-to-vm $VMNAME $1
      find $current_release -type f -name '*.deb' -delete
      rm -f $current_release/vm/db/*
      qrexec-client-vm $VMNAME local.UpdateApt



``local.UpdateApt`` service code
(``/usr/local/etc/qubes-rpc/local.UpdateApt`` in repo-serving VM):

.. code:: bash

      #!/bin/sh
      
      if [ -z "$QREXEC_REMOTE_DOMAIN" ]; then
          exit 1
      fi
      
      incoming=/home/user/QubesIncoming/$QREXEC_REMOTE_DOMAIN
      
      rsync -lr --remove-source-files $incoming/ /home/user/linux-deb/
      cd /home/user/linux-deb
      export SKIP_REPO_CHECK=1
      if [ -d $incoming/r3.1 ]; then
          for dist in `ls r3.1/vm/dists`; do
              ./update-local-repo.sh r3.1/vm $dist
          done
      fi
      
      if [ -d $incoming/r3.0 ]; then
          for dist in `ls r3.0/vm/dists`; do
              ./update-local-repo.sh r3.0/vm $dist
          done
      fi
      
      if [ -d $incoming/r2 ]; then
          for dist in `ls r2/vm/dists`; do
              ./update-local-repo.sh r2/vm $dist
          done
      fi
      find $incoming -type d -empty -delete
      exit 0



``update-local-repo.sh``:

.. code:: bash

      #!/bin/sh
      
      set -e
      
      # Set this to your local repository signing key
      SIGN_KEY=01ABCDEF
      
      [ -z "$1" ] && { echo "Usage: $0 <repo> <dist>"; exit 1; }
      
      REPO_DIR=$1
      DIST=$2
      
      if [ "$DIST" = "wheezy-unstable" ]; then
          DIST_TAG=deb7
      elif [ "$DIST" = "jessie-unstable" ]; then
          DIST_TAG=deb8
      elif [ "$DIST" = "stretch-unstable" ]; then
          DIST_TAG=deb9
      fi
      
      pushd $REPO_DIR
      mkdir -p dists/$DIST/main/binary-amd64
      dpkg-scanpackages --multiversion --arch "*$DIST_TAG*" . > dists/$DIST/main/binary-amd64/Packages
      gzip -9c dists/$DIST/main/binary-amd64/Packages > dists/$DIST/main/binary-amd64/Packages.gz
      cat > dists/$DIST/Release <<EOF
      Label: Test repo
      Suite: $DIST
      Codename: $DIST
      Date: `date -R`
      Architectures: amd64
      Components: main
      SHA1:
      EOF
      function calc_sha1() {
          f=dists/$DIST/$1
          echo -n " "
          echo -n `sha1sum $f|cut -d' ' -f 1` ""
          echo -n `stat -c %s $f` ""
          echo $1
      }
      calc_sha1 main/binary-amd64/Packages >> dists/$DIST/Release
      
      rm -f $DIST/Release.gpg
      rm -f $DIST/InRelease
      gpg -abs -u "$SIGN_KEY" \
          < dists/$DIST/Release > dists/$DIST/Release.gpg
      gpg -a -s --clearsign -u "$SIGN_KEY" \
          < dists/$DIST/Release > dists/$DIST/InRelease
      popd
      
      if [ `id -u` -eq 0 ]; then
          chown -R --reference=$REPO_DIR $REPO_DIR
      fi



Usage: add this line to ``/etc/apt/sources.list`` on test machine
(adjust host and path):

.. code:: bash

      deb http://local-test.lan/linux-deb/r3.1 jessie-unstable main