repl_installer: Upload hashes as file

Now, the upload and install are completely separate. This means you can now upload all files without pybricksdev and just call install from the REPL.

Author: laurensvalk

pybricksdev/repl_installer.py

@@ -119,7 +119,7 @@ async def install(self, firmware_archive_path):
         # Read Pybricks dual boot build
         archive = ZipFile(firmware_archive_path)
         pybricks_blob = archive.open('firmware-dual-boot-base.bin').read()
-        pybricks_hash = sha256(pybricks_blob).digest()
+        pybricks_hash = sha256(pybricks_blob).hexdigest().encode('utf-8')
 
         # Upload firmware file.
         await self.upload_file('_pybricks/firmware.bin', pybricks_blob)
@@ -129,12 +129,16 @@ async def install(self, firmware_archive_path):
 
         # Upload installation script.
         with open('pybricksdev/resources/install_pybricks.py', "rb") as install_script:
-            await self.upload_file('_pybricks/install.py', install_script.read())
+            install_blob = install_script.read()
+            install_hash = sha256(install_blob).hexdigest().encode('utf-8')
+            await self.upload_file('_pybricks/install.py', install_blob)
+
+        # Upload file with hashes to verify uploaded file integrity.
+        await self.upload_file('_pybricks/hash.txt', pybricks_hash + b"\n" + install_hash + b"\n")
 
         # Run the installation script
         self.print_output = True
-        await self.exec_line("from _pybricks.install import install")
-        await self.exec_line("install({0})".format(repr(pybricks_hash)))
+        await self.exec_line("from _pybricks.install import install; install()")
 
         # Remove installation files
         await self.exec_line("import uos")

pybricksdev/resources/install_pybricks.py

@@ -112,27 +112,42 @@ def get_padding(padding_length):
     yield FF * (padding_length % BLOCK_WRITE_SIZE)
 
 
-def install(pybricks_hash):
-    """Main installation routine."""
+def get_file_size_and_hash(path):
+    """Gets file size and sha256 hash."""
 
-    # Start firmware binary verification.
-    print("Starting installation script.")
-    print("Checking uploaded firmware file.")
-    pybricks_hash_calc = uhashlib.sha256()
-    pybricks_size = 0
+    hash_calc = uhashlib.sha256()
+    size = 0
 
-    with open("_pybricks/firmware.bin", "rb") as pybricks_bin_file:
+    with open(path, "rb") as bin_file:
         data = b'START'
         while len(data) > 0:
-            data = pybricks_bin_file.read(128)
-            pybricks_size += len(data)
-            pybricks_hash_calc.update(data)
+            data = bin_file.read(128)
+            size += len(data)
+            hash_calc.update(data)
+
+    return (size, ubinascii.hexlify(hash_calc.digest()).decode())
+
+
+def install():
+    """Main installation routine."""
+
+    print("Starting installation script.")
+
+    # Get hash of uploaded files.
+    print("Checking installation files.")
+    pybricks_size, pybricks_hash_calc = get_file_size_and_hash("_pybricks/firmware.bin")
+    script_size, script_hash_calc = get_file_size_and_hash("_pybricks/install.py")
+
+    # Read what the hashes should be.
+    with open("_pybricks/hash.txt") as hash_file:
+        pybricks_hash_read = hash_file.readline().strip()
+        script_hash_read = hash_file.readline().strip()
 
-    # Compare hash against given value.
-    if pybricks_hash_calc.digest() == pybricks_hash:
-        print("Firmware checksum is correct!")
+    # Check if hashes match.
+    if pybricks_hash_read == pybricks_hash_calc and script_hash_read == script_hash_calc:
+        print("Files looking good!")
     else:
-        print("Bad firmware file. Stopping.")
+        print("The installation files are corrupt.")
         return
 
     # Get firmware information.