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