lib/bup/drecurse.py

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