west: bindesc: Added get_offset command

Add `west bindesc get_offset` command to print the offset of
the descriptors inside the given image.

Signed-off-by: Yonatan Schachter <[email protected]>

Author: yonsch

doc/develop/west/zephyr-cmds.rst

@@ -215,3 +215,7 @@ You can dump all of the descriptors in an image using::
 You can list all known standard descriptor names using::
 
    west bindesc list
+
+You can print the offset of the descriptors inside the image using::
+
+   west bindesc get_offset

scripts/west_commands/bindesc.py

@@ -145,6 +145,13 @@ def do_add_parser(self, parser_adder):
         list_parser = subparsers.add_parser('list', help='List all known descriptors')
         list_parser.set_defaults(subcmd='list', big_endian=False)
 
+        get_offset_parser = subparsers.add_parser('get_offset', help='Get the offset of the descriptors')
+        get_offset_parser.add_argument('file', type=str, help='Executable file')
+        get_offset_parser.add_argument('--file-type', type=str, choices=self.EXTENSIONS,
+                                          help='File type')
+        get_offset_parser.add_argument('-b', '--big-endian', action='store_true',
+                                       help='Target CPU is big endian')
+        get_offset_parser.set_defaults(subcmd='get_offset', big_endian=False)
         return parser
 
     def dump(self, args):
@@ -188,6 +195,15 @@ def custom_search(self, args):
         custom_tag = self.bindesc_gen_tag(custom_type, int(args.id, 16))
         self.common_search(args, custom_tag)
 
+    def get_offset(self, args):
+        image = self.get_image_data(args.file)
+
+        magic = struct.pack('>Q' if self.is_big_endian else 'Q', self.MAGIC)
+        index = image.find(magic)
+        if index == -1:
+            log.die('Could not find binary descriptor magic')
+        log.inf(f'{index} {hex(index)}')
+
     def do_run(self, args, _):
         if MISSING_REQUIREMENTS:
             raise RuntimeError('one or more Python dependencies were missing; '