attachment:uidgidfix.py von rsync

   1 #!/usr/bin/env python
   2 """
   3 Repair damage caused by improper use of rsync (e.g. if you wanted to create a
   4 backup copy of a system using a another system with a different uid/gid mapping
   5 and you forgot to give --numeric-ids).
   6 
   7 If you still have the correct uid/gids on the original system, you can create
   8 a backup of them using (you need to be root, otherwise you might get some
   9 permission denied errors and a incomplete list):
  10 
  11     uidgidfix.py backup / > uidgidfix.lst
  12 
  13 You'll get a really long list in uidgidfix.lst then (if you need to start from
  14 a different directory than /, then just give that).
  15 
  16 Note: You likely want to review / edit that list before applying it to the
  17       damaged copy of the system. This script is NOT foolproof and comes
  18       without any warranty - USE IT ON YOUR OWN RISK!
  19 
  20 Testing the contents of uidgidfix.lst on the damaged system works like this:
  21 
  22     uidgidfix.py dryrun < uidgidfix.lst
  23 
  24 It will tell you what it WOULD change, but won't change anything.
  25 If you are really sure you want that, run it like this (you need to be root):
  26 
  27     uidgidfix.py restore < uidgidfix.lst
  28 
  29 @copyright: Thomas Waldmann <tw AT waldmann-edv DOT de>
  30 @license: GNU GPL v2 or any later version
  31 """
  32 
  33 # root:root is likely 0:0 on all systems, so we can skip that:
  34 SKIP_ROOT = True
  35 
  36 import os
  37 import sys
  38 import errno
  39 
  40 
  41 def backup(outfile, top):
  42     """
  43     create a uid gid pathname list
  44     
  45     @param outfile: open file to write output to
  46     @param top: path to start the recursion
  47     """
  48     for root, dirs, files in os.walk(top, topdown=False):
  49         absroot = os.path.abspath(root)
  50         for name in dirs + files:
  51             pathname = os.path.join(absroot, name)
  52             try:
  53                 st = os.lstat(pathname)
  54                 uid = st.st_uid
  55                 gid = st.st_gid
  56                 if not (SKIP_ROOT and uid == 0 and gid == 0):
  57                     outfile.write("%d %d %s\n" % (uid, gid, pathname))
  58             except OSError, err:
  59                 if err.errno != errno.ENOENT:
  60                     # we raise any exception except if a file just vanished
  61                     # (happens in /proc usually)
  62                     raise
  63 
  64 
  65 def restore(infile, dryrun):
  66     """
  67     read a uid gid pathname list and fix uid/gid on the local filesystem,
  68     if the file exists with a different uid/gid
  69 
  70     @param infile: open file to read list from
  71     @param dryrun: if True, do not change filesystem, but just tell about changes
  72     """
  73     for line in infile:
  74         line = line.rstrip('\n')
  75         uid, gid, pathname = line.split(' ', 2)
  76         uid = int(uid)
  77         gid = int(gid)
  78         if os.path.lexists(pathname):
  79             try:
  80                 st = os.lstat(pathname)
  81                 if uid != st.st_uid or gid != st.st_gid:
  82                     if dryrun:
  83                         print "%d:%d -> %d:%d %s" % (st.st_uid, st.st_gid, uid, gid, pathname)
  84                     else:
  85                         os.lchown(pathname, uid, gid)
  86             except OSError, err:
  87                 print str(err)
  88 
  89 
  90 if __name__ == '__main__':
  91     try:
  92         cmd = sys.argv[1]
  93     except IndexError:
  94         print __doc__
  95     else:
  96         if cmd == 'backup':
  97             try:
  98                 path = sys.argv[2]
  99             except IndexError:
 100                 path = '.'
 101             backup(sys.stdout, path)
 102         elif cmd == 'dryrun':
 103             restore(sys.stdin, True)
 104         elif cmd == 'restore':
 105             restore(sys.stdin, False)