118 lines
4.3 KiB
Python
Executable File
118 lines
4.3 KiB
Python
Executable File
#!/usr/bin/env python3
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"""
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Stage 4 – Restore filesystem metadata (permissions, ownership, timestamps) to
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an already-extracted directory tree.
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Run this after extract_tree.py if you did not use --restore-meta there, or to
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re-apply metadata without re-extracting files.
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Usage:
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python3 restore_meta.py [options] <inode> <dest_dir>
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Options:
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--device DEV Block device [/dev/dm-0]
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--backup-sb BLOCK Backup superblock block number [32768]
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--db PATH Optional: read metadata from SQLite DB instead of
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re-reading the device (faster) [inodes.db if present]
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"""
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import argparse, ctypes, ctypes.util, os, stat, sys
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import ext4lib
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DEFAULT_DEV = '/dev/dm-0'
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DEFAULT_BACKUP_SB = 32768
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# ── libc lutimes ──────────────────────────────────────────────────────────────
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_libc = ctypes.CDLL(ctypes.util.find_library('c'), use_errno=True)
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class _Timeval(ctypes.Structure):
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_fields_ = [('tv_sec', ctypes.c_long), ('tv_usec', ctypes.c_long)]
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def _lutimes(path, atime, mtime):
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times = (_Timeval * 2)((_Timeval(atime, 0)), (_Timeval(mtime, 0)))
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_libc.lutimes(path.encode(), ctypes.byref(times))
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# ── per-path restore ──────────────────────────────────────────────────────────
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def _apply_meta(dest_path, perms, uid, gid, atime, mtime):
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is_link = os.path.islink(dest_path)
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try:
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os.lchown(dest_path, uid, gid)
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except OSError:
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pass
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if not is_link:
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try:
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os.chmod(dest_path, perms)
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except OSError:
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pass
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try:
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_lutimes(dest_path, atime, mtime)
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except Exception:
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pass
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def restore_one(f, sb, gdt_data, inum, dest_path):
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try:
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idata, slot = ext4lib.read_inode(f, sb, gdt_data, inum)
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perms, uid, gid, atime, mtime = ext4lib.get_inode_meta(idata, slot, sb)
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_apply_meta(dest_path, perms, uid, gid, atime, mtime)
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except Exception as e:
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print(f" WARN {dest_path}: {e}", file=sys.stderr)
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# ── recursive walker ──────────────────────────────────────────────────────────
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def walk_and_restore(f, sb, gdt_data, inum, dest_dir, visited=None):
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if visited is None:
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visited = set()
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if inum in visited:
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return
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visited.add(inum)
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# Restore the directory itself first (to set ownership before descending)
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restore_one(f, sb, gdt_data, inum, dest_dir)
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try:
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entries = ext4lib.read_dir_entries(f, sb, gdt_data, inum)
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except Exception:
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return
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for name, (child_inum, ftype) in entries.items():
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if name in ('.', '..'):
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continue
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safe_name = name.replace('/', '_').replace('\x00', '')
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dest = os.path.join(dest_dir, safe_name)
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if not os.path.lexists(dest):
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continue
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if os.path.isdir(dest) and not os.path.islink(dest):
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walk_and_restore(f, sb, gdt_data, child_inum, dest, visited)
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else:
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restore_one(f, sb, gdt_data, child_inum, dest)
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# Re-apply directory timestamps after children are written
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restore_one(f, sb, gdt_data, inum, dest_dir)
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# ── main ──────────────────────────────────────────────────────────────────────
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def main():
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parser = argparse.ArgumentParser(description='Restore ext4 metadata to extracted tree (Stage 4)')
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parser.add_argument('inode', type=int)
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parser.add_argument('dest_dir')
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parser.add_argument('--device', default=DEFAULT_DEV)
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parser.add_argument('--backup-sb', type=int, default=DEFAULT_BACKUP_SB)
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args = parser.parse_args()
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with open(args.device, 'rb') as f:
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sb, gdt_data, _ = ext4lib.load_fs(f, args.backup_sb)
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print(f"Restoring metadata: inode {args.inode} → {args.dest_dir}")
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walk_and_restore(f, sb, gdt_data, args.inode, args.dest_dir)
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print("Done")
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if __name__ == '__main__':
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main()
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