ci: run USDT interface test in a VM

Our CI tasks are run by CirrusCI in Docker containers in a Google
Compute Engine based Kubernetes environment. These containers have
limited capabilities - especially CAP_SYS_ADMIN is missing. See
bitcoin#23296 (comment)

We need elevated privileges to hook into the USDT tracepoints. We use a
CirrusCI "compute_engine_instance" (a VM, not a container) where we have
the required privileges. The ubunut-mininmal-2204-lts was choosen with
debian-11 being an alternative. Both pack an outdated 'bpfcc-tools'
package (v0.18.0) from 2020. This version prints warnings to stderr
during BPF bytecode compilation, which causes our functional test runner
to fail. This is fixed in newer verison.

Until debian-12 or a newer Ubuntu release is avaliable as image in GCE
(https://cloud.google.com/compute/docs/images/os-details), we use a
third-party and untrusted PPA that releases up-to-date versions of the
package.

The official iovisor (authors of BCC) PPA is outdated too. An
alternative would be to compile BCC from source in the CI.

.cirrus.yml

@@ -340,3 +340,18 @@ task:
   env:
     << : *CIRRUS_EPHEMERAL_WORKER_TEMPLATE_ENV
     FILE_ENV: "./ci/test/00_setup_env_android.sh"
+
+task:
+  name: '[usdt interface tests] [GCE jammy VM]'
+  << : *GLOBAL_TASK_TEMPLATE
+  # We can't use a 'container' for the USDT interface tests as the CirrusCI
+  # containers don't have privileges to hook into bitcoind. CirrusCI uses
+  # Google Compute Engine instances: https://cirrus-ci.org/guide/custom-vms/
+  # Images can be found here: https://cloud.google.com/compute/docs/images/os-details
+  compute_engine_instance:
+    image_project: ubuntu-os-cloud
+    image: family/ubuntu-2204-lts # when upgrading, check if we can drop "ADD_UNTRUSTED_BPFCC_PPA"
+  env:
+    << : *CIRRUS_EPHEMERAL_WORKER_TEMPLATE_ENV
+    HOME: /root/
+    FILE_ENV: "./ci/test/00_setup_env_native_usdt.sh"

ci/test/00_setup_env_native_usdt.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2019-2021 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C.UTF-8
+
+# We install an up-to-date 'bpfcc-tools' package from an untrusted PPA.
+# This can be dropped with the next Ubuntu or Debian release that includes up-to-date packages.
+# See the if-then in ci/test/04_install.sh too.
+export ADD_UNTRUSTED_BPFCC_PPA=true
+export TRACING_PACKAGES="systemtap-sdt-dev bpfcc-tools"
+export PACKAGES="clang llvm python3-zmq qtbase5-dev qttools5-dev-tools libevent-dev bsdmainutils libboost-dev libdb5.3++-dev libminiupnpc-dev libnatpmp-dev libzmq3-dev libqrencode-dev libsqlite3-dev $TRACING_PACKAGES"
+export NO_DEPENDS=1
+export GOAL="install"
+export BITCOIN_CONFIG="--enable-c++20 --enable-zmq --enable-usdt --disable-bench --disable-fuzz --with-incompatible-bdb --without-gui CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' CC=clang CXX=clang++"

ci/test/04_install.sh

@@ -68,6 +68,14 @@ if [[ $DOCKER_NAME_TAG == *centos* ]]; then
   ${CI_RETRY_EXE} CI_EXEC dnf -y install epel-release
   ${CI_RETRY_EXE} CI_EXEC dnf -y --allowerasing install "$DOCKER_PACKAGES" "$PACKAGES"
 elif [ "$CI_USE_APT_INSTALL" != "no" ]; then
+  if [[ "${ADD_UNTRUSTED_BPFCC_PPA}" == "true" ]]; then
+    # Ubuntu 22.04 LTS and Debian 11 both have an outdated bpfcc-tools packages.
+    # The iovisor PPA is outdated as well. The next Ubuntu and Debian releases will contain updated
+    # packages. Meanwhile, use an untrusted PPA to install an up-to-date version of the bpfcc-tools
+    # package.
+    # TODO: drop this once we can use newer images in GCE
+    CI_EXEC add-apt-repository ppa:hadret/bpfcc
+  fi
   ${CI_RETRY_EXE} CI_EXEC apt-get update
   ${CI_RETRY_EXE} CI_EXEC apt-get install --no-install-recommends --no-upgrade -y "$PACKAGES" "$DOCKER_PACKAGES"
   if [ -n "$PIP_PACKAGES" ]; then
@@ -137,3 +145,4 @@ if [ "$USE_BUSY_BOX" = "true" ]; then
   # Print BusyBox version
   CI_EXEC patch --help
 fi
+