Fix benchmark integration script (google#1504)

The previous model used a submodule that was never updated and thus the
stuff copied from oss-fuzz repo was very old and generally not working.
Change this to use the latest oss-fuzz clone.

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "third_party/oss-fuzz"]
-	path = third_party/oss-fuzz
-	url = https://github.com/google/oss-fuzz.git

benchmarks/oss_fuzz_benchmark_integration.py

@@ -15,23 +15,24 @@
 will create benchmark.yaml as well as copy the files from OSS-Fuzz to build the
 benchmark."""
 import argparse
+import bisect
 import datetime
 from distutils import spawn
 from distutils import dir_util
+import json
 import os
 import sys
 import subprocess
-import json
-import bisect
+import tempfile
+
 
 from common import utils
 from common import benchmark_utils
 from common import logs
 from common import new_process
 from common import yaml_utils
 
-OSS_FUZZ_DIR = os.path.join(utils.ROOT_DIR, 'third_party', 'oss-fuzz')
-OSS_FUZZ_REPO_PATH = os.path.join(OSS_FUZZ_DIR, 'infra')
+OSS_FUZZ_REPO_URL = 'https://github.com/google/oss-fuzz'
 OSS_FUZZ_IMAGE_UPGRADE_DATE = datetime.datetime(
     year=2021, month=8, day=25, tzinfo=datetime.timezone.utc)
 
@@ -77,14 +78,10 @@ def find_digest(self, timestamp):
 def copy_oss_fuzz_files(project, commit_date, benchmark_dir):
     """Checks out the right files from OSS-Fuzz to build the benchmark based on
     |project| and |commit_date|. Then copies them to |benchmark_dir|."""
-    if not os.path.exists(os.path.join(OSS_FUZZ_DIR, '.git')):
-        logs.error(
-            '%s is not a git repo. Try running: git submodule update --init',
-            OSS_FUZZ_DIR)
-        raise RuntimeError('%s is not a git repo.' % OSS_FUZZ_DIR)
-    oss_fuzz_repo_manager = GitRepoManager(OSS_FUZZ_DIR)
-    project_dir = os.path.join(OSS_FUZZ_DIR, 'projects', project)
-    try:
+    with tempfile.TemporaryDirectory() as oss_fuzz_dir:
+        oss_fuzz_repo_manager = GitRepoManager(oss_fuzz_dir)
+        oss_fuzz_repo_manager.git(['clone', OSS_FUZZ_REPO_URL, oss_fuzz_dir])
+        project_dir = os.path.join(oss_fuzz_dir, 'projects', project)
         # Find an OSS-Fuzz commit that can be used to build the benchmark.
         _, oss_fuzz_commit, _ = oss_fuzz_repo_manager.git([
             'log', '--before=' + commit_date.isoformat(), '-n1', '--format=%H',
@@ -98,8 +95,6 @@ def copy_oss_fuzz_files(project, commit_date, benchmark_dir):
         dir_util.copy_tree(project_dir, benchmark_dir)
         os.remove(os.path.join(benchmark_dir, 'project.yaml'))
         return True
-    finally:
-        oss_fuzz_repo_manager.git(['reset', '--hard'])
 
 
 def get_benchmark_name(project, fuzz_target, benchmark_name=None):

docs/getting-started/prerequisites.md

@@ -23,7 +23,6 @@ Clone the FuzzBench repository to your machine by running the following command:
 ```bash
 git clone https://github.com/google/fuzzbench
 cd fuzzbench
-git submodule update --init
 ```
 
 ## Installing prerequisites

experiment/run_experiment.py

@@ -41,8 +41,6 @@
 
 BENCHMARKS_DIR = os.path.join(utils.ROOT_DIR, 'benchmarks')
 FUZZERS_DIR = os.path.join(utils.ROOT_DIR, 'fuzzers')
-OSS_FUZZ_PROJECTS_DIR = os.path.join(utils.ROOT_DIR, 'third_party', 'oss-fuzz',
-                                     'projects')
 RESOURCES_DIR = os.path.join(utils.ROOT_DIR, 'experiment', 'resources')
 FUZZER_NAME_REGEX = re.compile(r'^[a-z][a-z0-9_]+$')
 EXPERIMENT_CONFIG_REGEX = re.compile(r'^[a-z0-9-]{0,30}$')
@@ -56,7 +54,6 @@
                                  r'\#*\#$|'
                                  r'\.pytest_cache/|'
                                  r'.*/test_data/|'
-                                 r'^third_party/oss-fuzz/build/|'
                                  r'^docker/generated.mk$|'
                                  r'^docs/)')
 _OSS_FUZZ_CORPUS_BACKUP_URL_FORMAT = (