Initial remote commit

misc_tools/stump.py

@@ -0,0 +1,54 @@
+import struct
+
+CHUNK    = 128*512
+LV_START = 5120000*512
+BSIZE    = 4096
+BPG      = 32768
+
+def read_virt(virt_byte, length):
+    result = bytearray(length)
+    pos = virt_byte
+    remaining = length
+    with open('/dev/md0','rb') as f:
+        while remaining > 0:
+            group     = pos // (5*CHUNK)
+            in_group  = pos % (5*CHUNK)
+            chunk_idx = in_group // CHUNK
+            intra     = in_group % CHUNK
+            seg_len   = min(CHUNK-intra, remaining)
+            dst_off   = pos - virt_byte
+            if chunk_idx != 4:
+                phys = LV_START + group*4*CHUNK + chunk_idx*CHUNK + intra
+                f.seek(phys)
+                data = f.read(seg_len)
+                result[dst_off:dst_off+len(data)] = data
+            pos       += seg_len
+            remaining -= seg_len
+    return bytes(result)
+
+# Load GDT
+NUM_GROUPS = 35728
+gdt_data = read_virt(BSIZE, NUM_GROUPS*64)
+
+def get_block_bitmap_block(group):
+    entry = gdt_data[group*64:(group+1)*64]
+    bb_lo = struct.unpack_from('<I', entry,  0)[0]
+    bb_hi = struct.unpack_from('<I', entry, 32)[0]
+    return (bb_hi<<32)|bb_lo
+
+def is_block_allocated(block_num):
+    group  = block_num // BPG
+    offset = block_num % BPG
+    bb_block = get_block_bitmap_block(group)
+    bitmap = read_virt(bb_block*BSIZE, BSIZE)
+    byte_idx = offset // 8
+    bit_idx  = offset % 8
+    return bool(bitmap[byte_idx] & (1 << bit_idx))
+
+for block, name in [(6300141,'volumes'), (6299897,'pterodactyl'), (5251104,'var')]:
+    allocated = is_block_allocated(block)
+    virt = block * BSIZE
+    in_group  = virt % (5*CHUNK)
+    chunk_idx = in_group // CHUNK
+    print(f'{name:15s} block={block:8d} chunk_idx={chunk_idx} '
+          f'allocated={allocated}')