Refactor the inline Python commands into a Python binary.

fuzzing/engines/BUILD

@@ -23,6 +23,9 @@ cc_fuzzing_engine(
     name = "libfuzzer",
     display_name = "libFuzzer",
     launcher = "libfuzzer_launcher.sh",
+    launcher_data = {
+        "//fuzzing/tools:realpath": "REALPATH_PATH",
+    },
     library = ":libfuzzer_stub",
     visibility = ["//visibility:public"],
 )
@@ -46,6 +49,7 @@ cc_fuzzing_engine(
     launcher = "honggfuzz_launcher.sh",
     launcher_data = {
         "@honggfuzz//:honggfuzz": "HONGGFUZZ_PATH",
+        "//fuzzing/tools:realpath": "REALPATH_PATH",
     },
     library = "@honggfuzz//:honggfuzz_engine",
     visibility = ["//visibility:public"],
@@ -58,6 +62,9 @@ cc_fuzzing_engine(
     name = "replay",
     display_name = "Replay",
     launcher = "replay_launcher.sh",
+    launcher_data = {
+        "//fuzzing/tools:realpath": "REALPATH_PATH",
+    },
     library = "//fuzzing/replay:replay_main",
     visibility = ["//visibility:public"],
 )
@@ -69,6 +76,9 @@ java_fuzzing_engine(
     name = "jazzer",
     display_name = "Jazzer",
     launcher = "jazzer_launcher.sh",
+    launcher_data = {
+        "//fuzzing/tools:realpath": "REALPATH_PATH",
+    },
     library = "@jazzer//agent:jazzer_api_compile_only",
     visibility = ["//visibility:public"],
 )

fuzzing/engines/honggfuzz_launcher.sh

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-command_line="$(python3 -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' ${HONGGFUZZ_PATH})"
+command_line="$("${REALPATH_PATH}" ${HONGGFUZZ_PATH})"
 command_line+=("--workspace=${FUZZER_OUTPUT_ROOT}")
 
 if [[ -n "${FUZZER_SEED_CORPUS_DIR}" ]]; then

fuzzing/engines/jazzer_launcher.sh

@@ -16,7 +16,7 @@
 # engine. The launch configuration is supplied by the launcher script through
 # environment variables.
 
-command_line=("$(python3 -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' ${FUZZER_BINARY})")
+command_line=("$("${REALPATH_PATH}" ${FUZZER_BINARY})")
 
 # libFuzzer flags (compatible with Jazzer).
 

fuzzing/engines/libfuzzer_launcher.sh

@@ -16,7 +16,7 @@
 # libFuzzer engine. The launch configuration is supplied by the launcher
 # script through environment variables.
 
-command_line=("$(python3 -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' ${FUZZER_BINARY})")
+command_line=("$("${REALPATH_PATH}" ${FUZZER_BINARY})")
 
 # libFuzzer flags.
 

fuzzing/engines/replay_launcher.sh

@@ -16,7 +16,7 @@ if (( ! FUZZER_IS_REGRESSION )); then
     echo "NOTE: Non-regression mode is not supported by the replay engine."
 fi
 
-command_line=("$(python3 -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' ${FUZZER_BINARY})")
+command_line=("$("${REALPATH_PATH}" ${FUZZER_BINARY})")
 if [[ -n "${FUZZER_SEED_CORPUS_DIR}" ]]; then
     command_line+=("${FUZZER_SEED_CORPUS_DIR}")
 fi

fuzzing/private/engine.bzl

@@ -37,9 +37,12 @@ def _make_fuzzing_engine_info(ctx):
         if data_env_var:
             if data_env_var in env_vars:
                 fail("Multiple data dependencies map to variable '%s'." % data_env_var)
-            if len(data_files) != 1:
-                fail("Data dependency for variable '%s' doesn't map to exactly one file." % data_env_var)
-            env_vars[data_env_var] = data_files[0]
+            if len(data_files) == 1:
+                env_vars[data_env_var] = data_files[0]
+            elif data_label.files_to_run.executable:
+                env_vars[data_env_var] = data_label.files_to_run.executable
+            else:
+                fail("Data dependency for variable '%s' is not a single file or executable." % data_env_var)
         launcher_runfiles = launcher_runfiles.merge(ctx.runfiles(files = data_files))
         launcher_runfiles = launcher_runfiles.merge(data_label[DefaultInfo].default_runfiles)
 

fuzzing/tools/BUILD

@@ -36,6 +36,13 @@ py_binary(
     deps = [requirement("absl-py")],
 )
 
+py_binary(
+    name = "realpath",
+    srcs = ["realpath.py"],
+    python_version = "PY3",
+    visibility = ["//visibility:public"],
+)
+
 py_binary(
     name = "validate_dict",
     srcs = ["validate_dict.py"],

fuzzing/tools/realpath.py

@@ -0,0 +1,27 @@
+# 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.
+
+# Lint as: python3
+"""
+Gets the realpath of a input path.
+
+This is a portable replacement of `readlink -f`/`realpath`.
+"""
+
+import os, sys
+
+if len(sys.argv) < 2:
+    print("Need an argument for the input path.", file=sys.stderr)
+    sys.exit(1)
+print(os.path.realpath(sys.argv[1]))