.github/workflows/fuzzing.yml

#                          __  __            _
#                       ___\ \/ /_ __   __ _| |_
#                      / _ \\  /| '_ \ / _` | __|
#                     |  __//  \| |_) | (_| | |_
#                      \___/_/\_\ .__/ \__,_|\__|
#                               |_| XML parser
#
# Copyright (c) 2024      Sebastian Pipping <sebastian@pipping.org>
# Licensed under the MIT license:
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name: Run fuzzing regression tests

on:
  pull_request:
  push:
  schedule:
    - cron: '0 2 * * 5'  # Every Friday at 2am
  workflow_dispatch:

permissions:
  contents: read

jobs:
  run_fuzzers:
    name: Run fuzzing regression tests
    runs-on: ubuntu-22.04
    steps:
    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11  # v4.1.1

    - name: Install Clang 17
      run: |-
        set -x
        source /etc/os-release
        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
        sudo add-apt-repository "deb https://apt.llvm.org/${UBUNTU_CODENAME}/ llvm-toolchain-${UBUNTU_CODENAME}-17 main"
        sudo apt-get update  # due to new repository
        sudo apt-get install --yes --no-install-recommends -V \
            clang-17 \
            libclang-rt-17-dev \
            llvm-17
        echo /usr/lib/llvm-17/bin >>"${GITHUB_PATH}"

    - name: Build Expat fuzzers
      run: |
        set -x -o pipefail

        type -P clang clang++
        clang --version | head -n1
        clang++ --version | head -n1

        cd expat/
        args=(
            # Build nothing but fuzzers
            -DEXPAT_BUILD_DOCS=OFF
            -DEXPAT_BUILD_EXAMPLES=OFF
            -DEXPAT_BUILD_FUZZERS=ON
            -DEXPAT_BUILD_PKGCONFIG=OFF
            -DEXPAT_BUILD_TESTS=OFF
            -DEXPAT_BUILD_TOOLS=OFF

            # Tune compilation of fuzzers to use Clang with ASan and UBSan
            -DCMAKE_C_COMPILER=clang
            -DCMAKE_C_FLAGS='-Wall -Wextra -pedantic -O1 -g -fsanitize=memory -fno-sanitize-recover=all -fno-omit-frame-pointer -fno-common'
            -DCMAKE_{EXE,MODULE,SHARED}_LINKER_FLAGS='-g -fsanitize=memory'
            -DEXPAT_WARNINGS_AS_ERRORS=ON
        )
        cmake "${args[@]}" -S . -B build
        make -C build VERBOSE=1 -j$(nproc)

    - name: Download and extract Expat fuzzing corpora
      run: |-
        set -x
        cd expat/build/

        wget -q -O expat_corpus_UTF-8.zip    https://storage.googleapis.com/expat-backup.clusterfuzz-external.appspot.com/corpus/libFuzzer/expat_xml_parse_fuzzer_UTF-8/public.zip
        wget -q -O expat_corpus_UTF-16LE.zip https://storage.googleapis.com/expat-backup.clusterfuzz-external.appspot.com/corpus/libFuzzer/expat_xml_parse_fuzzer_UTF-16LE/public.zip

        unzip -q -d corpus_UTF-8    expat_corpus_UTF-8.zip
        unzip -q -d corpus_UTF-16LE expat_corpus_UTF-16LE.zip

    - name: Run fuzzing regression tests (10+ minutes)
      run: |
        fuzz_args=(
            -jobs=$(nproc)
            -print_final_stats=1
            -rss_limit_mb=2560  # from oss-fuzz
            -timeout=25         # from oss-fuzz
        )

        set -x -o pipefail
        cd expat/build/

        #           vvvvv
        find corpus_UTF-8/ -type f | sort | xargs \
            fuzz/xml_parse_fuzzer_UTF-8 "${fuzz_args[@]}"
        #                         ^^^^^
        #           vvvvvvvv
        find corpus_UTF-16LE/ -type f | sort | xargs \
            fuzz/xml_parsebuffer_fuzzer_UTF-16LE "${fuzz_args[@]}"
        #                 ^^^^^^        ^^^^^^^^

    - name: Store crashing test units
      if: ${{ failure() }}
      uses: actions/upload-artifact@c7d193f32edcb7bfad88892161225aeda64e9392  # v4.0.0
      with:
        name: expat_fuzzing_trouble_${{ github.sha }}
        path: expat/build/*-????????????????????????????????????????