Adjust uid/gid on all files and directories under a given root.

id-adjust.py

#!/usr/bin/env python3
#
# Adjust uid/gid on all files and directories under a given root.
# Adjustment can be made conditional on a minimum uid/gid. Adjustments
# can be either absolute or relative.
#
# Copyright (c) 2018-2023, Alexandre Hamelin <alexandre.hamelin gmail.com>
# Published under the MIT license.

import sys, os
from pathlib import Path


def adjown(file, stat, uid_adj, gid_adj):
    if uid_adj is not None:
        to_uid = stat.st_uid + uid_adj.value() if uid_adj.is_offset() else uid_adj.value()
    if gid_adj is not None:
        to_gid = stat.st_gid + gid_adj.value() if gid_adj.is_offset() else gid_adj.value()

    if uid_adj is not None or gid_adj is not None:
        if uid_adj is None: to_uid = stat.st_uid
        if gid_adj is None: to_gid = stat.st_gid
        os.chown(file, to_uid, to_gid, follow_symlinks=False)
        #print(f'chown({file}, {stat.st_uid}->{to_uid}, {stat.st_gid}->{to_gid})')
    #else:
    #    print(f'chown({file}) NOT CALLED')


class IdAdjustment:
    def __init__(self, arg):
        self._value = self._is_offset = None
        self._parse(arg)
    def is_offset(self):
        return self._is_offset
    def value(self):
        return self._value
    def _parse(self, arg):
        self._value = int(arg)
        self._is_offset = arg[0] in '+-'


if __name__ == '__main__':
    if len(sys.argv) < 4 or len(sys.argv) == 5 or sys.argv[0] in ('-h', '--help', 'help'):
        print(f'usage: {sys.argv[0]} rootpath [+|-]uid [+|-]gid [min-uid min-gid]')
        raise SystemExit

    rootpath = sys.argv[1]
    uid_adj = IdAdjustment(sys.argv[2])
    gid_adj = IdAdjustment(sys.argv[3])

    uid_min = gid_min = None
    if len(sys.argv) > 5:
        uid_min = int(sys.argv[4])
        gid_min = int(sys.argv[5])

    for basedir, dirs, files in os.walk(rootpath):

        stat = os.lstat(basedir)
        eff_uid_adj = uid_adj if uid_min is None or stat.st_uid >= uid_min else None
        eff_gid_adj = gid_adj if gid_min is None or stat.st_gid >= gid_min else None
        adjown(basedir, stat, eff_uid_adj, eff_gid_adj)

        # symlinks to directories are not reported as files, but rather as directories,
        # and we don't handle directories here, so add them manually to files[]
        files += [d for d in dirs if Path(basedir, d).is_symlink()]

        for f in files:
            fpath = Path(basedir, f)
            stat = os.lstat(fpath)
            eff_uid_adj = uid_adj if uid_min is None or stat.st_uid >= uid_min else None
            eff_gid_adj = gid_adj if gid_min is None or stat.st_gid >= gid_min else None
            adjown(fpath, stat, eff_uid_adj, eff_gid_adj)