lib/bup/drecurse.py

   1
   2 from __future__ import absolute_import
   3 import stat, os
   4
   5 from bup.compat import str_type
   6 from bup.helpers \
   7     import (add_error,
   8             debug1,
   9             finalized,
  10             resolve_parent,
  11             should_rx_exclude_path)
  12 from bup.io import path_msg
  13 import bup.xstat as xstat
  14
  15 # the use of fchdir() and lstat() is for two reasons:
  16 #  - help out the kernel by not making it repeatedly look up the absolute path
  17 #  - avoid race conditions caused by doing listdir() on a changing symlink
  18
  19 try:
  20     O_LARGEFILE = os.O_LARGEFILE
  21 except AttributeError:
  22     O_LARGEFILE = 0
  23 try:
  24     O_NOFOLLOW = os.O_NOFOLLOW
  25 except AttributeError:
  26     O_NOFOLLOW = 0
  27
  28
  29 def finalized_fd(path):
  30     fd = os.open(path, os.O_RDONLY|O_LARGEFILE|O_NOFOLLOW|os.O_NDELAY)
  31     return finalized(fd, lambda x: os.close(x))
  32
  33
  34 def _dirlist():
  35     l = []
  36     for n in os.listdir(b'.'):
  37         try:
  38             st = xstat.lstat(n)
  39         except OSError as e:
  40             add_error(Exception('%s: %s' % (resolve_parent(n), str(e))))
  41             continue
  42         if stat.S_ISDIR(st.st_mode):
  43             n += b'/'
  44         l.append((n,st))
  45     l.sort(reverse=True)
  46     return l
  47
  48 def _recursive_dirlist(prepend, xdev, bup_dir=None,
  49                        excluded_paths=None,
  50                        exclude_rxs=None,
  51                        xdev_exceptions=frozenset()):
  52     for (name,pst) in _dirlist():
  53         path = prepend + name
  54         if excluded_paths:
  55             if os.path.normpath(path) in excluded_paths:
  56                 debug1('Skipping %r: excluded.\n' % path_msg(path))
  57                 continue
  58         if exclude_rxs and should_rx_exclude_path(path, exclude_rxs):
  59             continue
  60         if name.endswith(b'/'):
  61             if bup_dir != None:
  62                 if os.path.normpath(path) == bup_dir:
  63                     debug1('Skipping BUP_DIR.\n')
  64                     continue
  65             if xdev != None and pst.st_dev != xdev \
  66                and path not in xdev_exceptions:
  67                 debug1('Skipping contents of %r: different filesystem.\n'
  68                        % path_msg(path))
  69             else:
  70                 try:
  71                     with finalized_fd(name) as fd:
  72                         os.fchdir(fd)
  73                 except OSError as e:
  74                     add_error('%s: %s' % (prepend, e))
  75                 else:
  76                     for i in _recursive_dirlist(prepend=prepend+name, xdev=xdev,
  77                                                 bup_dir=bup_dir,
  78                                                 excluded_paths=excluded_paths,
  79                                                 exclude_rxs=exclude_rxs,
  80                                                 xdev_exceptions=xdev_exceptions):
  81                         yield i
  82                     os.chdir(b'..')
  83         yield (path, pst)
  84
  85
  86 def recursive_dirlist(paths, xdev, bup_dir=None,
  87                       excluded_paths=None,
  88                       exclude_rxs=None,
  89                       xdev_exceptions=frozenset()):
  90     with finalized_fd(b'.') as startdir:
  91         try:
  92             assert not isinstance(paths, str_type)
  93             for path in paths:
  94                 try:
  95                     pst = xstat.lstat(path)
  96                     if stat.S_ISLNK(pst.st_mode):
  97                         yield (path, pst)
  98                         continue
  99                 except OSError as e:
 100                     add_error('recursive_dirlist: %s' % e)
 101                     continue
 102                 try:
 103                     opened_pfile = finalized_fd(path)
 104                 except OSError as e:
 105                     add_error(e)
 106                     continue
 107                 with opened_pfile as pfile:
 108                     pst = xstat.fstat(pfile)
 109                     if xdev:
 110                         xdev = pst.st_dev
 111                     else:
 112                         xdev = None
 113                     if stat.S_ISDIR(pst.st_mode):
 114                         os.fchdir(pfile)
 115                         prepend = os.path.join(path, b'')
 116                         for i in _recursive_dirlist(prepend=prepend, xdev=xdev,
 117                                                     bup_dir=bup_dir,
 118                                                     excluded_paths=excluded_paths,
 119                                                     exclude_rxs=exclude_rxs,
 120                                                     xdev_exceptions=xdev_exceptions):
 121                             yield i
 122                         os.fchdir(startdir)
 123                     else:
 124                         prepend = path
 125                 yield (prepend,pst)
 126         except:
 127             try:
 128                 os.fchdir(startdir)
 129             except:
 130                 pass
 131             raise