Add API Checker

ABI checker tools generate HTML and TXT API compatibility reports of
BIND libraries. Comparison is being done between two bind source trees
which hold built BIND.

In the CI one version is the reference version defined by
BIND_BASELINE_VERSION variable, the latter one is the HEAD of branch
under test.

.gitlab-ci.yml

@@ -1332,3 +1332,34 @@ respdiff:sid:amd64:
     untracked: true
     expire_in: "1 day"
     when: on_failure
+
+# ABI check
+
+abi-check:sid:amd64:
+  <<: *debian_sid_amd64_image
+  stage: build
+  dependencies:
+    - autoreconf:sid:amd64
+  needs:
+    - autoreconf:sid:amd64
+  variables:
+    CC: gcc
+    CFLAGS: "${CFLAGS_COMMON} -Og"
+    BIND_BASELINE_VERSION: v9_16_0
+  script:
+    - *configure
+    - ${MAKE} -j${BUILD_PARALLEL_JOBS:-1} V=1
+    - git clone --branch "${BIND_BASELINE_VERSION}" --depth 1 https://gitlab.isc.org/isc-projects/bind9.git refbind
+    - cd refbind/
+    - *configure
+    - ${MAKE} -j${BUILD_PARALLEL_JOBS:-1} V=1
+    - cd ..
+    - util/api-checker.sh . refbind
+  artifacts:
+    paths:
+      - "*.html"
+      - "abi-*.dump"
+    expire_in: "1 week"
+  only:
+    - master@isc-projects/bind9
+    - /^v9_[1-9][0-9]$/@isc-projects/bind9

util/api-checker.sh

@@ -0,0 +1,83 @@
+#!/bin/bash
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+set -e
+
+# Exit if program $1 is not found in PATH.
+check_program() {
+	if ! command -v "${1}" > /dev/null 2>&1; then
+		echo "'${1}' not found in PATH" >&2
+		exit 1
+	fi
+}
+
+# Check that we were spawned with two arguments and that these arguments are two
+# different directories.
+check_args() {
+	if [ ${#} -ne 2 ] || [ ! -d "${1}" ] || [ ! -d "${2}" ] || [ "${1}" = "${2}" ]; then
+		echo "Usage:"
+		echo ""
+		echo "  ${0} <TESTDIR> <REFDIR>"
+		echo ""
+		echo "Generate API compatibility reports for BIND libraries."
+		echo ""
+		echo "  <TESTDIR> is a directory with current (new) BIND version"
+		echo "  <REFDIR> is a directory with reference (old) BIND version"
+		exit 1
+	fi
+}
+
+check_args "${@}"
+TESTBIND="${1}"
+REFBIND="${2}"
+
+# Ensure the required tools are available in PATH.
+check_program abi-dumper
+check_program abi-compliance-checker
+check_program git
+check_program w3m
+
+# Find all libraries which have designated 'api' file and
+# generate ABI dump file for them.
+while read -r SO; do
+	APIFILE="$(dirname "${SO}")/../api"
+	pushd "$(dirname "${APIFILE}")"
+	GIT_REVISION=$(git rev-parse HEAD | cut -c 1-10)
+	popd
+	# Get LIBINTERFACE, LIBREVISION, LIBAGE from the 'api' file.
+	eval "$(grep -v "^#" "${APIFILE}" | tr -d " ")"
+	VERSION="${LIBINTERFACE}.${LIBREVISION}.${LIBAGE}-${GIT_REVISION}"
+	abi-dumper "${SO}" -o abi-"$(basename "${SO}" .so)-${VERSION}".dump -lver "${VERSION}"
+done < <(find "${TESTBIND}"/lib/*/.libs/ "${REFBIND}"/lib/*/.libs/ -name '*.so')
+
+# Generate HTML API compatibility reports for all libraries.
+find . -maxdepth 1 -name 'abi-*.dump' | sort | while read -r OLD; read -r NEW; do
+	SONAME=${OLD/.\/abi-/}
+	SONAME=${SONAME/-*/}
+	if abi-compliance-checker -l "${SONAME}" -old "${OLD}" -new "${NEW}"; then
+		REPORT_PREFIX="PASS"
+	else
+		echo "***** Compatibility problems detected"
+		REPORT_PREFIX="WARN"
+	fi
+	OLD_REPORT_PATH="$(find "compat_reports/${SONAME}" -name '*.html')"
+	NEW_REPORT_PATH="${REPORT_PREFIX}-${SONAME}.html"
+	mv "${OLD_REPORT_PATH}" "${NEW_REPORT_PATH}"
+	echo
+done
+
+# Generate TXT API compatibility reports from HTML reports for all BIND libraries.
+echo "Generate TXT API compatibility reports from HTML reports for all BIND libraries:"
+while read -r HTMLREPORT; do
+	TXTREPORT="${HTMLREPORT/.html/.txt}"
+	echo "  w3m: ${HTMLREPORT} -> ${TXTREPORT}"
+	w3m -dump -cols 75 -O ascii -T text/html "${HTMLREPORT}" > "${TXTREPORT}"
+done < <(find . -maxdepth 1 -name '*.html')

util/copyrights

@@ -2566,6 +2566,7 @@
 ./util/COPYRIGHT.NOM				X	2001,2004,2007,2016,2018,2019,2020
 ./util/COPYRIGHT.PORTION			X	1996,1997,1998,1999,2000,2001,2004,2007,2016,2018,2019,2020
 ./util/COPYRIGHT.TOP				X	2018,2019,2020
+./util/api-checker.sh				SH	2020
 ./util/bindkeys.pl				PERL	2009,2010,2011,2012,2014,2016,2017,2018,2019,2020
 ./util/branchsync.sh				SH	2013,2016,2018,2019,2020
 ./util/check-ans-prereq.sh			SH	2019,2020