fuzzing/private/regression.bzl

# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Regression testing rule for fuzz tests."""

load("//fuzzing/private:binary.bzl", "FuzzingBinaryInfo")

def _fuzzing_regression_test_impl(ctx):
    binary_info = ctx.attr.binary[FuzzingBinaryInfo]
    script = ctx.actions.declare_file(ctx.label.name)
    script_template = """
export FUZZER_OUTPUT_CORPUS_DIR="$TEST_TMPDIR/corpus"
export FUZZER_ARTIFACTS_DIR="$TEST_TMPDIR/artifacts"
export FUZZER_BINARY='{fuzzer_binary}'
export FUZZER_SEED_CORPUS_DIR='{seed_corpus_dir}'
export FUZZER_IS_REGRESSION=1
export PYTHON3_INTERPRETER='{python3_interpreter_path}'
{engine_launcher_environment}

mkdir -p "$FUZZER_OUTPUT_CORPUS_DIR"
mkdir -p "$FUZZER_ARTIFACTS_DIR"

exec '{engine_launcher}'
"""
    runfiles = ctx.runfiles()
    runfiles = runfiles.merge(ctx.attr.binary[DefaultInfo].default_runfiles)
    runfiles = runfiles.merge(binary_info.engine_info.launcher_runfiles)

    py3_runtime = ctx.toolchains["@rules_python//python:toolchain_type"].py3_runtime
    if py3_runtime.interpreter:
        runfiles = runfiles.merge(ctx.runfiles(files = [py3_runtime.interpreter]))
        runfiles = runfiles.merge(ctx.runfiles(files = py3_runtime.files.to_list()))
        python3_interpreter_path = py3_runtime.interpreter.short_path
    else:
        python3_interpreter_path = py3_runtime.interpreter_path

    script_content = script_template.format(
        fuzzer_binary = ctx.executable.binary.short_path,
        seed_corpus_dir = binary_info.corpus_dir.short_path,
        python3_interpreter_path = python3_interpreter_path,
        engine_launcher_environment = "\n".join([
            "export %s='%s'" % (var, file.short_path)
            for var, file in binary_info.engine_info.launcher_environment.items()
        ]),
        engine_launcher = binary_info.engine_info.launcher.short_path,
    )
    ctx.actions.write(script, script_content, is_executable = True)
    return [DefaultInfo(executable = script, runfiles = runfiles)]

fuzzing_regression_test = rule(
    implementation = _fuzzing_regression_test_impl,
    doc = """
Executes a fuzz test on its seed corpus.
""",
    attrs = {
        "binary": attr.label(
            executable = True,
            doc = "The instrumented executable of the fuzz test to run.",
            providers = [FuzzingBinaryInfo],
            cfg = "target",
            mandatory = True,
        ),
    },
    toolchains = ["@rules_python//python:toolchain_type"],
    test = True,
)