ci: Add a test app for not placing embedded file paths into binaries

Doubles as a test app that building with assertions off doesn't produce warnings.

Closes https://github.com/espressif/esp-idf/issues/6306

tools/ci/executable-list.txt

@@ -99,6 +99,7 @@ tools/mass_mfg/mfg_gen.py
 tools/mkdfu.py
 tools/mkuf2.py
 tools/set-submodules-to-github.sh
+tools/test_apps/system/no_embedded_paths/check_for_file_paths.py
 tools/test_idf_monitor/run_test_idf_monitor.py
 tools/test_idf_py/test_idf_py.py
 tools/test_idf_size/test.sh

tools/test_apps/system/no_embedded_paths/CMakeLists.txt

@@ -0,0 +1,20 @@
+# The following lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(no_embedded_paths)
+
+idf_build_get_property(idf_path IDF_PATH)
+idf_build_get_property(python PYTHON)
+idf_build_get_property(elf EXECUTABLE)
+
+# If the configuration is one that doesn't expect any paths to be found then run this build step
+# after building the ELF, will fail if it finds any file paths in binary files
+if(CONFIG_OPTIMIZATION_ASSERTIONS_SILENT OR CONFIG_OPTIMIZATION_ASSERTIONS_DISABLED)
+    add_custom_command(
+        TARGET ${elf}
+        POST_BUILD
+        COMMAND ${python} "${CMAKE_CURRENT_LIST_DIR}/check_for_file_paths.py" "${idf_path}" "${CMAKE_BINARY_DIR}"
+        )
+endif()

tools/test_apps/system/no_embedded_paths/README.md

@@ -0,0 +1,14 @@
+# No Embedded Paths
+
+This test app exists to verify that paths (like __FILE__) are not compiled into
+any object files in configurations where this should be avoided.
+
+It doubles up as a build-time check that disabling assertions doesn't lead to
+any warnings.
+
+(These configurations include: assertions disabled, 'silent' asserts, any reproducible
+builds configuration.)
+
+Not embedding paths reduces the binary size, avoids leaking information about
+the compilation environment, and is a necessary step to supporet reproducible
+builds across projects built in different directories.

tools/test_apps/system/no_embedded_paths/check_for_file_paths.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+#
+# 'check_for_file_paths.py' is a CI tool that checks all the unlinked object files
+# in a CMake build directory for embedded copies of IDF_PATH.
+#
+# Designed to be run in CI as a check that __FILE__ macros haven't snuck into any source code.
+#
+# Checking the unlinked object files means we don't rely on anything being actually linked into the binary,
+# just anything which could potentially be linked.
+#
+# Usage:
+# ./check_for_file_paths.py <IDF_PATH> <BUILD_DIR>
+#
+#
+#
+# Copyright 2019 Espressif Systems (Shanghai) PTE LTD
+#
+# 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
+#
+#     http://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.
+#
+import os
+import re
+import sys
+
+from elftools.elf.elffile import ELFFile
+
+# If an ESP-IDF source file has no option but to include __FILE__ macros, name it here (as re expression).
+#
+# IMPORTANT: This should only be used for upstream code where there is no other
+# option. ESP-IDF code should avoid embedding file names as much as possible to
+# limit the binary size and support reproducible builds
+#
+# Note: once ESP-IDF moves to Python >=3.6 then this can be simplified to use 'glob' and '**'
+EXCEPTIONS = [
+    r'openssl/.+/ssl_pm.c.obj$',  # openssl API requires __FILE__ in error reporting functions, as per upstream API
+    r'openssl/.+/ssl_bio.c.obj$',
+    r'unity/.+/unity_runner.c.obj$',  # unity is not for production use, has __FILE__ for test information
+]
+
+
+def main():  # type: () -> None
+    idf_path = sys.argv[1]
+    build_dir = sys.argv[2]
+
+    assert os.path.exists(idf_path)
+    assert os.path.exists(build_dir)
+
+    print('Checking object files in {} for mentions of {}...'.format(build_dir, idf_path))
+
+    # note: once ESP-IDF moves to Python >=3.6 then this can be simplified to use 'glob' and f'{build_dir}**/*.obj'
+    files = []
+    for (dirpath, _, filepaths) in os.walk(build_dir):
+        files += [os.path.join(dirpath, filepath) for filepath in filepaths if filepath.endswith('.obj')]
+
+    print('Found {} object files...'.format(len(files)))
+
+    idf_path_binary = idf_path.encode()  # we're going to be checking binary streams (note: probably non-ascii IDF_PATH will not match OK)
+
+    failures = 0
+    for obj_file in files:
+        if not any(re.search(exception, obj_file) for exception in EXCEPTIONS):
+            failures += check_file(obj_file, idf_path_binary)
+    if failures > 0:
+        raise SystemExit('{} source files are embedding file paths, see list above.'.format(failures))
+    print('No embedded file paths found')
+
+
+def check_file(obj_file, idf_path):   # type: (str, bytes) -> int
+    failures = 0
+    with open(obj_file, 'rb') as f:
+        elf = ELFFile(f)
+        for sec in elf.iter_sections():
+            # can't find a better way to filter out only sections likely to contain strings,
+            # and exclude debug sections. .dram matches DRAM_STR, which links to .dram1
+            if '.rodata' in sec.name or '.dram' in sec.name:
+                contents = sec.data()
+                if idf_path in contents:
+                    print('error: {} contains an unwanted __FILE__ macro'.format(obj_file))
+                    failures += 1
+                    break
+    return failures
+
+
+if __name__ == '__main__':
+    main()

tools/test_apps/system/no_embedded_paths/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "test_no_embedded_paths_main.c"
+                       INCLUDE_DIRS ".")

tools/test_apps/system/no_embedded_paths/main/test_no_embedded_paths_main.c

@@ -0,0 +1,4 @@
+/* This test app only exists for the build stage, so doesn't need to do anything at runtime */
+void app_main(void)
+{
+}

tools/test_apps/system/no_embedded_paths/sdkconfig.ci.noasserts

@@ -0,0 +1,8 @@
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_DISABLE=y
+CONFIG_FREERTOS_ASSERT_DISABLE=y
+
+# compiling as many files as possible here (we don't have 100% coverage of course, due to config options, but
+# try to maximize what we can check
+CONFIG_BT_ENABLED=y
+CONFIG_BT_BLUEDROID_ENABLED=y
+CONFIG_BLE_MESH=y

tools/test_apps/system/no_embedded_paths/sdkconfig.ci.noasserts.nimble

@@ -0,0 +1,13 @@
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_DISABLE=y
+CONFIG_FREERTOS_ASSERT_DISABLE=y
+
+# the other sdkconfig builds Bluedroid, build NimBLE here
+#
+# (Note: ESP32-S2 will build both these configs as well, but they're identical. This is simpler than
+# needing to specify per-target configs for both Bluedroid and Nimble on ESP32, ESP32-C3.)
+CONFIG_BT_ENABLED=y
+CONFIG_BT_NIMBLE_ENABLED=y
+CONFIG_BT_NIMBLE_CRYPTO_STACK_MBEDTLS=n
+CONFIG_BT_NIMBLE_MESH=y
+CONFIG_BLE_MESH=y
+CONFIG_BT_NIMBLE_MAX_CONNECTIONS=1

tools/test_apps/system/no_embedded_paths/sdkconfig.ci.silentasserts

@@ -0,0 +1,7 @@
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_SILENT=y
+
+# compiling as many files as possible here (we don't have 100% coverage of course, due to config options, but
+# try to maximize what we can check
+CONFIG_BT_ENABLED=y
+CONFIG_BT_BLUEDROID_ENABLED=y
+CONFIG_BLE_MESH=y

tools/test_apps/system/no_embedded_paths/sdkconfig.ci.silentasserts.nimble

@@ -0,0 +1,13 @@
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_SILENT=y
+CONFIG_FREERTOS_ASSERT_DISABLE=y
+
+# the other sdkconfig builds Bluedroid, build NimBLE here
+#
+# (Note: ESP32-S2 will build both these configs as well, but they're identical. This is simpler than
+# needing to specify per-target configs for both Bluedroid and Nimble on ESP32, ESP32-C3.)
+CONFIG_BT_ENABLED=y
+CONFIG_BT_NIMBLE_ENABLED=y
+CONFIG_BT_NIMBLE_CRYPTO_STACK_MBEDTLS=n
+CONFIG_BT_NIMBLE_MESH=y
+CONFIG_BLE_MESH=y
+CONFIG_BT_NIMBLE_MAX_CONNECTIONS=1