base-runner: check fuzz target validity for jvm targets

[DavidKorczynski]

When running fuzz targets we check for validity by checking if LLVMFuzzerTestOneInput exists in the target file:

oss-fuzz/infra/base-images/base-runner/coverage

Lines 307 to 314 in 8d1f130

	elif [[ $FUZZING_LANGUAGE == "jvm" ]]; then
	# Continue if not a fuzz target.
	if [[ $FUZZING_ENGINE != "none" ]]; then
	grep "LLVMFuzzerTestOneInput" $fuzz_target > /dev/null 2>&1 || continue
	fi
	echo "Running $fuzz_target"
	run_java_fuzz_target $fuzz_target &

However, this is not done in the post processing step of the coverage utility:

oss-fuzz/infra/base-images/base-runner/coverage

Lines 415 to 418 in 8d1f130

	mkdir $classes_dir
	for fuzz_target in $FUZZ_TARGETS; do
	cp -r $DUMPS_DIR/${fuzz_target}_classes/* $classes_dir/
	done

This causes coverage build issues e.g.
https://oss-fuzz-build-logs.storage.googleapis.com/log-b8d4899d-ecc3-498c-8485-2e88d162dc57.txt

Step #5: [INFO] Loading execution data file /workspace/out/libfuzzer-coverage-x86_64/dumps/OpenSSHConfigFuzzer.exec.
Step #5: [INFO] Analyzing 3 classes.
Step #5: [INFO] Loading execution data file /workspace/out/libfuzzer-coverage-x86_64/dumps/OpenSSHConfigFuzzer.exec.
Step #5: [INFO] Writing execution data to /workspace/out/libfuzzer-coverage-x86_64/dumps/jacoco.merged.exec.
Step #5: cp: cannot stat '/workspace/out/libfuzzer-coverage-x86_64/dumps/jsch-fuzzer-0.2.10-SNAPSHOT.jar_classes/*': No such file or directory
Step #5: ********************************************************************************

[oliverchang]

thanks!

[oliverchang]

/gcbrun trial_build.py all --sanitizer coverage --fuzzing-engine libfuzzer

[jonathanmetzman]

/gcbrun trial_build.py asteval --sanitizer coverage --fuzzing-engine libfuzzer

[jonathanmetzman]

Other test fails looked spurious. Please merge if this trial build succeeds.

[jonathanmetzman]

Well last build of asteval failed, so looks like we don't care about breaking it again.