Improve binbase_find.py

Signed-off-by: Markus Birth <markus@birth-online.de>

binbase_find.py

@@ -10,6 +10,7 @@ import sys
 from operator import itemgetter
 
 chars = "A-Za-z0-9/\\-:.,_$%'\"()[\]<> "
+known_strings = [b"POSIX", b"ASCII", b"Foretrex", b" V3.50", b"0:/Garmin", b"Garmin International", b"<?xml version"]
 min_length = 10
 scores = []
 top_score = 0
@@ -31,20 +32,33 @@ def get_strings(filename, size):
                 data = f.read(10)
             except:
                 break
+            for ks in known_strings:
+                i = data.find(ks)
+                if i >= 0:
+                    print("matched known string: {}".format(ks))
+                    table.add(offset + i)
+                    offset += i + len(ks)
+                    continue
+
             match = pattern.match(data)
             if match:
+                print(repr(match))
                 f.seek(offset - 1)
                 try:
                     char = f.read(1)
                 except:
                     continue
                 if not patternc.match(char):
-                    table.add(offset)
+                    #table.add(offset)
                     offset += len(match.group(0))
             offset += 1
+    table.add(0xbb0e4)
     return table
 
 def get_pointers(filename):
+    """
+    Read file in DWORD chunks and assume everything is a pointer.
+    """
     table = {}
     with open(filename, "rb") as f:
         while True:
@@ -90,19 +104,23 @@ if __name__ == "__main__":
 
     for base in range(args.min_addr, args.max_addr, args.page_size):
         if base % ( args.page_size * 1000 ) == 0:
-            print("Trying base address 0x{:x}".format(base))
+            print("Trying base address 0x{:x}/0x{:x}".format(base, args.max_addr))
             print("\u001b[F\u001b[K", end="")
         score = 0
         ptrs = list(ptr_table.keys())
         for ptr in ptrs:
             if ptr < base:
+                # Pointer points to before base address --> invalid and remove from future queries
                 #print("Removing pointer 0x{:x} from table".format(ptr))
                 del ptr_table[ptr]
                 continue
             if ptr >= (base + size):
+                # Pointer points to after firmware area --> invalid, but might become valid when checking higher base addrs
                 continue
+            # Pointer points somewhere inside firmware, calculate offset
             offset = ptr - base
             if offset in str_table:
+                # Wow, pointer points directly to one of the found strings --> we have a winner
                 score += ptr_table[ptr]
         if score:
             scores.append((base, score))