From aaea75bb087895247ee0b28bf5a9aa058271430a Mon Sep 17 00:00:00 2001
From: Markus Birth <mbirth@gmail.com>
Date: Wed, 16 Oct 2019 01:48:03 +0200
Subject: [PATCH] Started parsing for hwid / version.

---
 grmn/devices.py |  1 +
 grmn/rgn.py     | 13 +++++++
 grmn/rgnbin.py  | 91 ++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 101 insertions(+), 4 deletions(-)

diff --git a/grmn/devices.py b/grmn/devices.py
index 39316fa..1c0faea 100644
--- a/grmn/devices.py
+++ b/grmn/devices.py
@@ -180,6 +180,7 @@ DEVICES = {
      954: "Chartplotters Minimum Software for g2 charts (954)",
      955: "Chartplotters Minimum Software for g2 charts (955)",
      956: "Honda Navi Gen3",
+     957: "eTrex Legend H/Vista H",
      960: "Dakota",
      969: "Firmware Update for FMI Cables with Traffic",
      970: "Mount Software",
diff --git a/grmn/rgn.py b/grmn/rgn.py
index 8a601ba..42b91b8 100644
--- a/grmn/rgn.py
+++ b/grmn/rgn.py
@@ -19,9 +19,14 @@ REGION_TYPES = {
     0x000c: "boot.bin",
     0x000e: "fw_all.bin",
     0x0010: "logo.bin",
+    0x0029: "NonVol (old)",
     0x004e: "ZIP file",
     0x0055: "fw_all2.bin",
+    0x009a: "NonVol (new)",
     0x00f5: "GCD firmware update file",
+    0x00f9: "Display firmware",
+    0x00fa: "ANT firmware",
+    0x00fb: "WiFi firmware",
     0x00ff: "pk_text.zip",
 }
 
@@ -52,6 +57,7 @@ class Rgn:
                 (length, type_id) = unpack("<Lc", header)
                 #print("Found record type: {} with {} Bytes length.".format(type_id, length))
                 rec = RgnRecord.factory(type_id, length, offset=cur_offset)
+                rec.parent = self
                 payload = f.read(length)
                 rec.set_payload(payload)
                 self.add_rec(rec)
@@ -75,6 +81,7 @@ class Rgn:
             (length, type_id) = unpack("<Lc", header)
             #print("Found record type: {} with {} Bytes length.".format(type_id, length))
             rec = RgnRecord.factory(type_id, length, offset=cur_offset)
+            rec.parent = self
             inner_payload = payload[pos:pos+length]
             pos += length
             rec.set_payload(inner_payload)
@@ -121,6 +128,7 @@ class Rgn:
 
 class RgnRecord():
     def __init__(self, type_id, expected_length, payload=None, offset=None):
+        self.parent = None
         self.type_id = type_id
         self.length = expected_length
         self.is_binary = False
@@ -267,10 +275,15 @@ class RgnRecordR(RgnRecord):
         payload_type = self.id_payload()
         if payload_type == "RGN":
             txt += "\n  " + YELLOW + "PAYLOAD IS ANOTHER RGN STRUCTURE:" + RESET
+            #with open("innerrgn.rgn", "wb") as f:
+            #    f.write(self.payload[10:])
+            #    f.close()
             rgn = Rgn()
             rgn.load_from_bytes(self.payload[10:])
             txt += "\n      " + "\n      ".join(str(rgn).split("\n"))
         elif payload_type == "BIN":
+            #with open("{}_{}.bin".format(self.parent.filename, self.offset), "wb") as f:
+            #    f.write(self.payload[10:])
             binfw = RgnBin()
             binfw.load_from_bytes(self.payload[10:])
             txt += "\n      " + "\n      ".join(str(binfw).split("\n"))
diff --git a/grmn/rgnbin.py b/grmn/rgnbin.py
index 0367706..c0fbefb 100644
--- a/grmn/rgnbin.py
+++ b/grmn/rgnbin.py
@@ -18,7 +18,9 @@ class ParseException(Exception):
 class RgnBin:
     def __init__(self, filename: str=None):
         self.filename = filename
-        self.struct = []
+        self.hwid = None
+        self.version = None
+        self.payload = None
         if filename is not None:
             self.load()
 
@@ -30,14 +32,95 @@ class RgnBin:
             f.close()
         self.load_from_bytes(rawdata)
 
+    def find_metadata(self):
+        try:
+            end_loc = self.payload.rindex(END_PATTERN)
+            #print("end_loc: {}".format(end_loc))
+        except ValueError:
+            # No END_PATTERN found
+            end_loc = None
+        jmp = unpack("<L", self.payload[0:4])[0]
+        print("JMP: 0x{:08x}".format(jmp))
+        hwid_addr = None
+        swver_addr = None
+        if jmp == 0xe59ff008:
+            # Variant 1a or 1b (end > hwid > swver > entry OR hwid > swver > end > entry)
+            (x1, x2, x3, entry_addr) = unpack("<LLLL", self.payload[4:20])
+            print("{:04x} / {:04x} / {:04x} / {:04x}".format(x1, x2, x3, entry_addr))
+            # HWID and SWVER are near each other
+            if abs(x2 - x1) == 2:
+                # Assume 1b: x1 = hw_id, x2 = swver
+                delta = 20 - entry_addr
+                hwid_addr = x1 + delta
+                swver_addr = x2 + delta
+            else:
+                # Assume 1a: x2 = hw_id, x3 = swver
+                delta = 20 - entry_addr
+                hwid_addr = x2 + delta
+                swver_addr = x3 + delta
+        if jmp == 0xe59ff00c:
+            print(RED + "Checking for 2" + RESET)
+            # Variant 2 (end > hwid > swver > lend > entry)
+            (end_addr, hwid_addr, swver_addr, lend_addr, entry_addr) = unpack("<LLLlL", self.payload[4:24])
+            print("hwid_addr: {} / swver_addr: {}".format(hwid_addr, swver_addr))
+            print("end_addr: {} / lend_addr: {} / entry_addr: {}".format(end_addr, lend_addr, entry_addr))
+            if lend_addr < 0:
+                load_addr = -lend_addr
+                print("load_addr: {}".format(load_addr))
+                delta = 24 - load_addr
+            else:
+                delta = 24 - entry_addr
+            print("delta: {}".format(delta))
+            hwid_addr += delta
+            swver_addr += delta
+            print("hwaddr: {} / swveraddr: {}".format(hwid_addr, swver_addr))
+            # expected hw_addr: 0x4b5e = 19294 / swver: 0x4b60 = 19296
+        if end_loc and jmp == 0xea000002:
+            # Variant 3 (end > hwid > swver)
+            (end_addr, hwid_addr, swver_addr) = unpack("<LLL", self.payload[4:16])
+            delta = end_loc + 2 - end_addr
+            hwid_addr += delta
+            swver_addr += delta
+        if jmp == 0xea000003:
+            print(RED + "Checking for 4" + RESET)
+            # Variant 4 (end > hwid > swver > ???)
+
+        if jmp == 0xea000004:
+            print(RED + "checking for 5" + RESET)
+            # Variant 5
+
+        if hwid_addr:
+            if hwid_addr < 0 or hwid_addr > len(self.payload)-2:
+                print(RED + "HWID OFFSET {:04x} OUT OF BOUNDS {:04x}".format(hwid_addr, len(self.payload)) + RESET)
+            else:
+                self.hwid = unpack("<H", self.payload[hwid_addr:hwid_addr+2])[0]
+        if swver_addr:
+            if swver_addr < 0 or swver_addr > len(self.payload)-2:
+                print(RED + "SWVER OFFSET {:04x} OUT OF BOUNDS {:04x}".format(swver_addr, len(self.payload)) + RESET)
+            else:
+                self.version = unpack("<H", self.payload[swver_addr:swver_addr+2])[0]
+
+        # Try EOF-4
+        if not self.hwid and not self.version:
+            print("Checking for EOF-4")
+            (hwid, version) = unpack("<HH", self.payload[-6:-2])
+            if hwid < 0xffff and version < 0xffff:
+                print("EOF-4 matches")
+                self.hwid = hwid
+                self.version = version
+
+        return None
+
     def load_from_bytes(self, payload: bytes):
         self.payload = payload
-        print(repr(payload[0:10]))
-        jmp = unpack("<L", payload[0:4])[0]
-        print("{:08x}".format(jmp))
+        self.find_metadata()
 
     def __str__(self):
         txt = "Binary payload, {} Bytes".format(len(self.payload))
+        if self.hwid:
+            txt += "\n  -    hw_id: 0x{:04x} / {:d} ({})".format(self.hwid, self.hwid, devices.DEVICES.get(self.hwid, RED + "Unknown device" + RESET))
+        if self.version:
+            txt += "\n  -  Version: 0x{:04x} / {:d}".format(self.version, self.version)
         cksum = ChkSum()
         cksum.add(self.payload)
         exp_byte = cksum.get_expected()