add: bootstrap height at 4421701

sugarchain-project/sugarchain#143

* scripts: In linearize, search for next position of magic bytes rather than fail
bitcoin/bitcoin#16802

* add: bootstrap height at 4421701

README.md

@@ -3,11 +3,12 @@ Construct a linear, no-fork, best version of the Bitcoin blockchain. The scripts
 run using Python 3 but are compatible with Python 2.
 
 ## Warning
-    Do not use `-txindex=1` in this script.
+Do not use `-txindex=1` in this script.
 
-## Stop 0: Fix `max_height` in `linearize.cfg`
+## Step 1:
+Fix `max_height` in `linearize.cfg`
 
-## Step 1: Download hash list
+## Step 1.1: Download hash list
 
     $ ./linearize-hashes.py linearize.cfg > hashlist.txt
 
@@ -28,19 +29,20 @@ the same data no matter which byte format is chosen.
 The `linearize-hashes` script requires a connection, local or remote, to a
 JSON-RPC server. Running `bitcoind` or `bitcoin-qt -server` will be sufficient.
 
-## Step 1.1: Change absolute location in `linearize.cfg`
+## Step 1.2:
+Change absolute location in `linearize.cfg`
 
     input=/home/{USERNAME}/.sugarchain/blocks
     output_file=/home/{USERNAME}/Desktop/bootstrap.dat
 
-## Step 1.2: Check outputs
+## Step 1.3: Check outputs
 
     $ head -1 hashlist.txt # genesis
       7d5eaec2dbb75f99feadfa524c78b7cabc1d8c8204f79d4f3a83381b811b0adc
-    $ wc -l hashlist.txt # 2601001+1 (add genesis)
-      2601002 hashlist.txt
-    $ tail -n 1 hashlist.txt # height 2601001 # getblockhash 2601001
-      56e8f536feb26f749ed9198f56f397da08f018de9518674b2ac12a41061612cb
+    $ wc -l hashlist.txt # 4421701+1 (add genesis)
+      4421702 hashlist.txt
+    $ tail -n 1 hashlist.txt # height 4421701 # getblockhash 4421701
+      9a9c7db86b1a67a399d50f7f45b1d4bbb9179bcf0be08331239a1b9881ebcea9
 
 ## Step 2: Copy local block data
 

linearize-data.py

@@ -215,8 +215,11 @@ def run(self):
 
 			inMagic = inhdr[:4]
 			if (inMagic != self.settings['netmagic']):
-				print("Invalid magic: " + hexlify(inMagic).decode('utf-8'))
-				return
+				# Seek backwards 7 bytes (skipping the first byte in the previous search)
+				# and continue searching from the new position if the magic bytes are not
+				# found.
+				self.inF.seek(-7, os.SEEK_CUR)
+				continue
 			inLenLE = inhdr[4:]
 			su = struct.unpack("<I", inLenLE)
 			inLen = su[0] - 80 # length without header

linearize.cfg

@@ -14,9 +14,9 @@ port=34229
 #port=45339
 
 # bootstrap.dat hashlist settings (linearize-hashes)
-# at this moment, the height is approx. 2825602 (2020-02-03)
-# 510*(510*10)+1
-max_height=2601001
+# at this moment, the height is approx. 4638846 (2020-05-18)
+# (510*510*17)+1=4421701
+max_height=4421701
 
 # bootstrap.dat input/output settings (linearize-data)