fix(ble_ota): Added script for Delta OTA patch generation

Author: Astha-cpu

examples/bluetooth/ble_ota/README.md

@@ -145,10 +145,17 @@ pip install -r tools/requirements.txt
 
 To create a patch file, use the [python tool](./tools/esp_delta_ota_patch_gen.py)
 ```
-python esp_delta_ota_patch_gen.py --chip <target> --base_binary <base_binary> --new_binary <new_binary> --patch_file_name <patch_file_name>
+python esp_delta_ota_patch_gen.py create_patch --chip <target> --base_binary <base_binary> --new_binary <new_binary> --patch_file_name <patch_file_name>
 ```
 
 This will generate the patch file for the new binary which needs to be hosted on the OTA update server.
 
 > **_NOTE:_** Make sure that the firmware present in the device is used as `base_binary` while creating the patch file. For this purpose, user should keep backup
 of the firmware running in the device as it is required for creating the patch file.
+
+### Verifying Patch
+
+To verify that the patch file is correctly created from the provided base binary and new binary, use the following command:
+```
+python esp_delta_ota_patch_gen.py verify_patch --chip <target> --base_binary <base_binary> --new_binary <new_binary> --patch_file_name <patch_file_name>
+```

examples/bluetooth/ble_ota/tools/esp_delta_ota_patch_gen.py

@@ -0,0 +1,139 @@
+#!/usr/bin/env python
+#
+# ESP Delta OTA Patch Generator Tool. This tool helps in generating the compressed patch file
+# using BSDiff and Heatshrink algorithms
+#
+# SPDX-FileCopyrightText: 2023-2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Apache-2.0
+
+import argparse
+import os
+import re
+import tempfile
+import hashlib
+import sys
+import esptool
+
+try:
+    import detools
+except ImportError:
+    print("Please install 'detools'. Use command `pip install -r tools/requirements.txt`")
+    sys.exit(1)
+
+# Magic Byte is created using command: echo -n "esp_delta_ota" | sha256sum
+esp_delta_ota_magic = 0xfccdde10
+
+MAGIC_SIZE = 4 # This is the size of the magic byte
+DIGEST_SIZE = 32 # This is the SHA256 of the base binary
+HEADER_SIZE = 64
+RESERVED_HEADER = HEADER_SIZE - (MAGIC_SIZE + DIGEST_SIZE) # This is the reserved header size
+
+def calculate_sha256(file_path: str) -> str:
+    """Calculate the SHA-256 hash of a file."""
+    sha256_hash = hashlib.sha256()
+
+    with open(file_path, 'rb') as f:
+        # Read the file in chunks to avoid memory issues for large files
+        for byte_block in iter(lambda: f.read(4096), b''):
+            sha256_hash.update(byte_block)
+
+    # Return the hex representation of the hash
+    return sha256_hash.hexdigest()
+
+def create_patch(chip: str, base_binary: str, new_binary: str, patch_file_name: str) -> None:
+    command = ['--chip', chip, 'image_info', base_binary]
+    output = sys.stdout
+    sys.stdout = tempfile.TemporaryFile(mode='w+')
+    try:
+        esptool.main(command)
+        sys.stdout.seek(0)
+        content = sys.stdout.read()
+    except Exception as e:
+        print(f'Error during esptool command execution: {e}')
+    finally:
+        sys.stdout.close()
+        sys.stdout = output
+
+    x = re.search(r'Validation Hash: ([A-Za-z0-9]+) \(valid\)', content)
+
+    if x is None:
+        print('Failed to find validation hash in base binary.')
+        return
+    patch_file_without_header = 'patch_file_temp.bin'
+    try:
+        with open(base_binary, 'rb') as b_binary, open(new_binary, 'rb') as n_binary, open(patch_file_without_header, 'wb') as p_binary:
+            detools.create_patch(b_binary, n_binary, p_binary, compression='heatshrink') # b_binary is the base binary, n_binary is the new binary, p_binary is the patch file without header
+
+        with open(patch_file_without_header, 'rb') as p_binary, open(patch_file_name, 'wb') as patch_file:
+            patch_file.write(esp_delta_ota_magic.to_bytes(MAGIC_SIZE, 'little'))
+            patch_file.write(bytes.fromhex(x[1]))
+            patch_file.write(bytearray(RESERVED_HEADER))
+            patch_file.write(p_binary.read())
+    except Exception as e:
+        print(f'Error during patch creation: {e}')
+    finally:
+        if os.path.exists(patch_file_without_header):
+            os.remove(patch_file_without_header)
+
+    print('Patch created successfully.')
+    # Verifying the created patch file
+    verify_patch(base_binary, patch_file_name, new_binary)
+
+# This API applies the patch file over the base_binary file and generates the binary.new file. Then it compares
+# the hash of new_binary and binary.new, if they are the same then the verification is successful, otherwise it fails.
+def verify_patch(base_binary: str, patch_to_verify: str, new_binary: str) -> None:
+
+    with open(patch_to_verify, 'rb') as original_file:
+        original_file.seek(HEADER_SIZE)
+        patch_content = original_file.read()
+
+    temp_file_name = None
+    try:
+        with tempfile.NamedTemporaryFile(delete=False) as temp_file:
+            temp_file.write(patch_content)
+            temp_file.flush()
+            temp_file_name = temp_file.name
+
+        detools.apply_patch_filenames(base_binary, temp_file_name, 'binary.new')
+    except Exception as e:
+        print(f'Failed to apply patch: {e}')
+    finally:
+        if temp_file_name and os.path.exists(temp_file_name):
+            os.remove(temp_file_name)
+
+    sha_of_new_created_binary = calculate_sha256('binary.new')
+    sha_of_new_binary = calculate_sha256(new_binary)
+
+    if sha_of_new_created_binary == sha_of_new_binary:
+        print('Patch file verified successfully')
+    else:
+        print('Failed to verify the patch')
+    os.remove('binary.new')
+
+def main() -> None:
+    if len(sys.argv) < 2:
+        print('Usage: python esp_delta_ota_patch_gen.py create_patch/verify_patch [arguments]')
+        sys.exit(1)
+
+    command = sys.argv[1]
+    parser = argparse.ArgumentParser('Delta OTA Patch Generator Tool')
+
+    if command == 'create_patch':
+        parser.add_argument('--chip', help='Target', default='esp32')
+        parser.add_argument('--base_binary', help='Path of Base Binary for creating the patch', required=True)
+        parser.add_argument('--new_binary', help='Path of New Binary for which patch has to be created', required=True)
+        parser.add_argument('--patch_file_name', help='Patch file path', default='patch.bin')
+        args = parser.parse_args(sys.argv[2:])
+        create_patch(args.chip, args.base_binary, args.new_binary, args.patch_file_name)
+    elif command == 'verify_patch':
+        parser.add_argument('--base_binary', help='Path of Base Binary for verifying the patch', required=True)
+        parser.add_argument('--patch_file_name', help='Patch file path', required=True)
+        parser.add_argument('--new_binary', help='Path of New Binary for verifying the patch', required=True)
+        args = parser.parse_args(sys.argv[2:])
+        verify_patch(args.base_binary, args.patch_file_name, args.new_binary)
+    else:
+        print("Invalid command. Use 'create_patch' or 'verify_patch'.")
+        sys.exit(1)
+
+if __name__ == '__main__':
+    main()

examples/bluetooth/ble_ota/tools/requirements.txt

@@ -0,0 +1 @@
+detools>=0.49.0

tools/ci/executable-list.txt

@@ -5,6 +5,7 @@ components/utilities/xz/xz-embedded/linux/scripts/xz_wrap.sh
 docs/check_lang_folder_sync.sh
 docs/zh_CN/conf.py
 docs/zh_CN/conf.py
+examples/bluetooth/ble_ota/tools/esp_delta_ota_patch_gen.py
 examples/elf_loader/elf_loader_example/main/test_riscv.elf
 examples/elf_loader/elf_loader_example/main/test_xtensa.elf
 examples/usb/device/bootloader_uf2/utils/redirect.sh