cpython: f42cabe6ccb5 (original) (raw)

Mercurial > cpython

changeset 82121:f42cabe6ccb5

Issue #6975: os.path.realpath() now correctly resolves multiple nested symlinks on POSIX platforms. [#6975]

Serhiy Storchaka storchaka@gmail.com
date	Sun, 10 Feb 2013 12:24:06 +0200
parents	bd6a2fcc7711(current diff)bfe9526606e2(diff)
children	12d75ca12ae7
files	Lib/posixpath.py Lib/test/test_posixpath.py Misc/NEWS
diffstat	3 files changed, 105 insertions(+), 39 deletions(-)[+] [-] Lib/posixpath.py 86 Lib/test/test_posixpath.py 55 Misc/NEWS 3

line wrap: on

line diff

--- a/Lib/posixpath.py +++ b/Lib/posixpath.py @@ -363,51 +363,59 @@ def abspath(path): def realpath(filename): """Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path."""

if isinstance(filename, bytes):

path, ok = _joinrealpath(filename[:0], filename, {})
return abspath(path)

+ +# Join two paths, normalizing ang eliminating any symbolic links +# encountered in the second path. +def _joinrealpath(path, rest, seen):

if isinstance(path, bytes): sep = b'/'

```
   empty = b''[](#l1.16)
```

```
   curdir = b'.'[](#l1.17)
```
```
   pardir = b'..'[](#l1.18)
```
else: sep = '/'

```
   empty = ''[](#l1.21)
```
if isabs(filename):

   bits = [sep] + filename.split(sep)[1:][](#l1.23)

else:

   bits = [empty] + filename.split(sep)[](#l1.25)

```
   curdir = '.'[](#l1.26)
```
```
   pardir = '..'[](#l1.27)
```

for i in range(2, len(bits)+1):

   component = join(*bits[0:i])[](#l1.30)

```
   # Resolve symbolic links.[](#l1.31)
```
```
   if islink(component):[](#l1.32)
```

       resolved = _resolve_link(component)[](#l1.33)

```
       if resolved is None:[](#l1.34)
```

           # Infinite loop -- return original component + rest of the path[](#l1.35)

           return abspath(join(*([component] + bits[i:])))[](#l1.36)

```
       else:[](#l1.37)
```

           newpath = join(*([resolved] + bits[i:]))[](#l1.38)

           return realpath(newpath)[](#l1.39)

return abspath(filename)

if isabs(rest):
```
   rest = rest[1:][](#l1.43)
```
```
   path = sep[](#l1.44)
```

while rest:

   name, _, rest = rest.partition(sep)[](#l1.47)

   if not name or name == curdir:[](#l1.48)

```
       # current dir[](#l1.49)
```
```
       continue[](#l1.50)
```
```
   if name == pardir:[](#l1.51)
```
```
       # parent dir[](#l1.52)
```
```
       if path:[](#l1.53)
```

           path = dirname(path)[](#l1.54)

```
       else:[](#l1.55)
```
```
           path = name[](#l1.56)
```
```
       continue[](#l1.57)
```
```
   newpath = join(path, name)[](#l1.58)
```
```
   if not islink(newpath):[](#l1.59)
```
```
       path = newpath[](#l1.60)
```
```
       continue[](#l1.61)
```

   # Resolve the symbolic link[](#l1.62)

```
   if newpath in seen:[](#l1.63)
```

       # Already seen this path[](#l1.64)

```
       path = seen[newpath][](#l1.65)
```
```
       if path is not None:[](#l1.66)
```
```
           # use cached value[](#l1.67)
```
```
           continue[](#l1.68)
```

       # The symlink is not resolved, so we must have a symlink loop.[](#l1.69)

       # Return already resolved part + rest of the path unchanged.[](#l1.70)

       return join(newpath, rest), False[](#l1.71)

   seen[newpath] = None # not resolved symlink[](#l1.72)

   path, ok = _joinrealpath(path, os.readlink(newpath), seen)[](#l1.73)

```
   if not ok:[](#l1.74)
```

       return join(path, rest), False[](#l1.75)

   seen[newpath] = path # resolved symlink[](#l1.76)

-def _resolve_link(path):

"""Internal helper function. Takes a path and follows symlinks
until we either arrive at something that isn't a symlink, or
encounter a path we've seen before (meaning that there's a loop).
"""
paths_seen = set()
while islink(path):
```
   if path in paths_seen:[](#l1.85)
```

       # Already seen this path, so we must have a symlink loop[](#l1.86)

```
       return None[](#l1.87)
```
```
   paths_seen.add(path)[](#l1.88)
```

   # Resolve where the link points to[](#l1.89)

   resolved = os.readlink(path)[](#l1.90)

```
   if not isabs(resolved):[](#l1.91)
```
```
       dir = dirname(path)[](#l1.92)
```

       path = normpath(join(dir, resolved))[](#l1.93)

```
   else:[](#l1.94)
```

       path = normpath(resolved)[](#l1.95)

return path

return path, True

+ supports_unicode_filenames = (sys.platform == 'darwin')

--- a/Lib/test/test_posixpath.py +++ b/Lib/test/test_posixpath.py @@ -320,6 +320,22 @@ class PosixPathTest(unittest.TestCase): self.assertEqual(realpath(ABSTFN+"1"), ABSTFN+"1") self.assertEqual(realpath(ABSTFN+"2"), ABSTFN+"2")

       self.assertEqual(realpath(ABSTFN+"1/x"), ABSTFN+"1/x")[](#l2.7)

       self.assertEqual(realpath(ABSTFN+"1/.."), dirname(ABSTFN))[](#l2.8)

       self.assertEqual(realpath(ABSTFN+"1/../x"), dirname(ABSTFN) + "/x")[](#l2.9)

       os.symlink(ABSTFN+"x", ABSTFN+"y")[](#l2.10)

       self.assertEqual(realpath(ABSTFN+"1/../" + basename(ABSTFN) + "y"),[](#l2.11)

                        ABSTFN + "y")[](#l2.12)

       self.assertEqual(realpath(ABSTFN+"1/../" + basename(ABSTFN) + "1"),[](#l2.13)

                        ABSTFN + "1")[](#l2.14)

       os.symlink(basename(ABSTFN) + "a/b", ABSTFN+"a")[](#l2.16)

       self.assertEqual(realpath(ABSTFN+"a"), ABSTFN+"a/b")[](#l2.17)

       os.symlink("../" + basename(dirname(ABSTFN)) + "/" +[](#l2.19)

                  basename(ABSTFN) + "c", ABSTFN+"c")[](#l2.20)

       self.assertEqual(realpath(ABSTFN+"c"), ABSTFN+"c")[](#l2.21)

+ # Test using relative path as well. os.chdir(dirname(ABSTFN)) self.assertEqual(realpath(basename(ABSTFN)), ABSTFN) @@ -328,6 +344,45 @@ class PosixPathTest(unittest.TestCase): support.unlink(ABSTFN) support.unlink(ABSTFN+"1") support.unlink(ABSTFN+"2")

       support.unlink(ABSTFN+"y")[](#l2.30)

       support.unlink(ABSTFN+"c")[](#l2.31)

@unittest.skipUnless(hasattr(os, "symlink"),

                    "Missing symlink implementation")[](#l2.34)

@skip_if_ABSTFN_contains_backslash
def test_realpath_repeated_indirect_symlinks(self):
```
   # Issue #6975.[](#l2.37)
```
```
   try:[](#l2.38)
```
```
       os.mkdir(ABSTFN)[](#l2.39)
```

       os.symlink('../' + basename(ABSTFN), ABSTFN + '/self')[](#l2.40)

       os.symlink('self/self/self', ABSTFN + '/link')[](#l2.41)

       self.assertEqual(realpath(ABSTFN + '/link'), ABSTFN)[](#l2.42)

```
   finally:[](#l2.43)
```

       support.unlink(ABSTFN + '/self')[](#l2.44)

       support.unlink(ABSTFN + '/link')[](#l2.45)

```
       safe_rmdir(ABSTFN)[](#l2.46)
```

@unittest.skipUnless(hasattr(os, "symlink"),

                    "Missing symlink implementation")[](#l2.49)

@skip_if_ABSTFN_contains_backslash
def test_realpath_deep_recursion(self):
```
   depth = 10[](#l2.52)
```
```
   old_path = abspath('.')[](#l2.53)
```
```
   try:[](#l2.54)
```
```
       os.mkdir(ABSTFN)[](#l2.55)
```
```
       for i in range(depth):[](#l2.56)
```

           os.symlink('/'.join(['%d' % i] * 10), ABSTFN + '/%d' % (i + 1))[](#l2.57)

       os.symlink('.', ABSTFN + '/0')[](#l2.58)

       self.assertEqual(realpath(ABSTFN + '/%d' % depth), ABSTFN)[](#l2.59)

       # Test using relative path as well.[](#l2.61)

```
       os.chdir(ABSTFN)[](#l2.62)
```

       self.assertEqual(realpath('%d' % depth), ABSTFN)[](#l2.63)

```
   finally:[](#l2.64)
```
```
       os.chdir(old_path)[](#l2.65)
```

       for i in range(depth + 1):[](#l2.66)

           support.unlink(ABSTFN + '/%d' % i)[](#l2.67)

```
       safe_rmdir(ABSTFN)[](#l2.68)
```

@unittest.skipUnless(hasattr(os, "symlink"), "Missing symlink implementation")

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -244,6 +244,9 @@ Core and Builtins Library ------- +- Issue #6975: os.path.realpath() now correctly resolves multiple nested

symlinks on POSIX platforms. +

Issue #13773: sqlite3.connect() gets a new uri parameter to pass the filename as a URI, allowing to pass custom options.