lib/bup/drecurse.py

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