lib/bup/drecurse.py

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