Initial remote commit

test/inspect.py

@@ -0,0 +1,88 @@
+import struct
+
+CHUNK    = 128 * 512
+LV_START = 5120000 * 512
+BSIZE    = 4096
+IPG      = 8192
+INODE_SIZE = 256
+
+def read_virt(virt_offset, length):
+    result = bytearray(length)
+    pos = virt_offset
+    remaining = length
+    with open('/dev/nbd0', 'rb') as f:
+        while remaining > 0:
+            f.seek(pos)
+            chunk = f.read(min(remaining, 65536))
+            if not chunk: break
+            dst = pos - virt_offset
+            result[dst:dst+len(chunk)] = chunk
+            pos += len(chunk)
+            remaining -= len(chunk)
+    return bytes(result)
+
+def get_inode_table_block(group):
+    # Use backup GDT at group 1
+    gdt_start = (1 * 32768 + 1) * BSIZE
+    entry = read_virt(gdt_start + group * 64, 64)
+    it_lo = struct.unpack_from('<I', entry, 8)[0]
+    it_hi = struct.unpack_from('<I', entry, 40)[0]
+    return (it_hi << 32) | it_lo
+
+def read_inode(inode_num):
+    group = (inode_num - 1) // IPG
+    index = (inode_num - 1) % IPG
+    it_block = get_inode_table_block(group)
+    inode_off = it_block * BSIZE + index * INODE_SIZE
+    return read_virt(inode_off, INODE_SIZE)
+
+def read_extents(inode_data):
+    blocks = []
+    eh_magic   = struct.unpack_from('<H', inode_data, 40)[0]
+    if eh_magic != 0xf30a:
+        return blocks
+    eh_entries = struct.unpack_from('<H', inode_data, 42)[0]
+    eh_depth   = struct.unpack_from('<H', inode_data, 46)[0]
+    if eh_depth == 0:
+        for i in range(min(eh_entries, 4)):
+            off = 52 + i * 12
+            ee_len     = struct.unpack_from('<H', inode_data, off+4)[0]
+            ee_start_hi = struct.unpack_from('<H', inode_data, off+6)[0]
+            ee_start_lo = struct.unpack_from('<I', inode_data, off+8)[0]
+            ee_start = (ee_start_hi << 32) | ee_start_lo
+            for b in range(ee_len):
+                blocks.append(ee_start + b)
+    return blocks
+
+def list_dir(inode_num):
+    inode_data = read_inode(inode_num)
+    mode  = struct.unpack_from('<H', inode_data, 0)[0]
+    size  = struct.unpack_from('<I', inode_data, 4)[0]
+    links = struct.unpack_from('<H', inode_data, 26)[0]
+    print(f'Inode {inode_num}: mode=0x{mode:04x} size={size} links={links}')
+
+    entries = []
+    for block_num in read_extents(inode_data):
+        data = read_virt(block_num * BSIZE, BSIZE)
+        off = 0
+        while off < BSIZE - 8:
+            ino     = struct.unpack_from('<I', data, off)[0]
+            rec_len = struct.unpack_from('<H', data, off+4)[0]
+            name_len = data[off+6]
+            ftype   = data[off+7]
+            if rec_len < 8: break
+            if ino > 0 and name_len > 0:
+                name = data[off+8:off+8+name_len].decode('utf-8',errors='replace')
+                grp  = (ino-1)//IPG
+                entries.append((name, ino, ftype, grp))
+            off += rec_len
+
+    type_names = {1:'file',2:'dir',7:'symlink'}
+    print(f'Directory entries ({len(entries)}):')
+    for name, ino, ftype, grp in sorted(entries):
+        status = 'INTACT' if grp >= 13 else 'LOST'
+        tname  = type_names.get(ftype, str(ftype))
+        print(f'  [{status}] {tname:6s} inode={ino:10d} group={grp:6d} {name!r}')
+
+# Read the volumes directory
+list_dir(1585918)