[Python-checkins] cpython (2.7): Issue #6975: os.path.realpath() now correctly resolves multiple nested symlinks
serhiy.storchaka
python-checkins at python.org
Sun Feb 10 11:27:47 CET 2013
http://hg.python.org/cpython/rev/6ec6dbf787f4
changeset: 82118:6ec6dbf787f4
branch: 2.7
user: Serhiy Storchaka <storchaka at gmail.com>
date: Sun Feb 10 12:21:49 2013 +0200
summary:
Issue #6975: os.path.realpath() now correctly resolves multiple nested symlinks on POSIX platforms.
files:
Lib/posixpath.py | 75 +++++++++++++------------
Lib/test/test_posixpath.py | 49 ++++++++++++++++
Misc/NEWS | 3 +
3 files changed, 92 insertions(+), 35 deletions(-)
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -364,46 +364,51 @@
def realpath(filename):
"""Return the canonical path of the specified filename, eliminating any
symbolic links encountered in the path."""
- if isabs(filename):
- bits = ['/'] + filename.split('/')[1:]
- else:
- bits = [''] + filename.split('/')
+ path, ok = _joinrealpath('', filename, {})
+ return abspath(path)
- for i in range(2, len(bits)+1):
- component = join(*bits[0:i])
- # Resolve symbolic links.
- if islink(component):
- resolved = _resolve_link(component)
- if resolved is None:
- # Infinite loop -- return original component + rest of the path
- return abspath(join(*([component] + bits[i:])))
+# Join two paths, normalizing ang eliminating any symbolic links
+# encountered in the second path.
+def _joinrealpath(path, rest, seen):
+ if isabs(rest):
+ rest = rest[1:]
+ path = sep
+
+ while rest:
+ name, _, rest = rest.partition(sep)
+ if not name or name == curdir:
+ # current dir
+ continue
+ if name == pardir:
+ # parent dir
+ if path:
+ path = dirname(path)
else:
- newpath = join(*([resolved] + bits[i:]))
- return realpath(newpath)
+ path = name
+ continue
+ newpath = join(path, name)
+ if not islink(newpath):
+ path = newpath
+ continue
+ # Resolve the symbolic link
+ if newpath in seen:
+ # Already seen this path
+ path = seen[newpath]
+ if path is not None:
+ # use cached value
+ continue
+ # The symlink is not resolved, so we must have a symlink loop.
+ # Return already resolved part + rest of the path unchanged.
+ return join(newpath, rest), False
+ seen[newpath] = None # not resolved symlink
+ path, ok = _joinrealpath(path, os.readlink(newpath), seen)
+ if not ok:
+ return join(path, rest), False
+ seen[newpath] = path # resolved symlink
- return abspath(filename)
+ return path, True
-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:
- # Already seen this path, so we must have a symlink loop
- return None
- paths_seen.add(path)
- # Resolve where the link points to
- resolved = os.readlink(path)
- if not isabs(resolved):
- dir = dirname(path)
- path = normpath(join(dir, resolved))
- else:
- path = normpath(resolved)
- return path
-
supports_unicode_filenames = (sys.platform == 'darwin')
def relpath(path, start=curdir):
diff --git a/Lib/test/test_posixpath.py b/Lib/test/test_posixpath.py
--- a/Lib/test/test_posixpath.py
+++ b/Lib/test/test_posixpath.py
@@ -236,6 +236,22 @@
self.assertEqual(realpath(ABSTFN+"1"), ABSTFN+"1")
self.assertEqual(realpath(ABSTFN+"2"), ABSTFN+"2")
+ self.assertEqual(realpath(ABSTFN+"1/x"), ABSTFN+"1/x")
+ self.assertEqual(realpath(ABSTFN+"1/.."), dirname(ABSTFN))
+ self.assertEqual(realpath(ABSTFN+"1/../x"), dirname(ABSTFN) + "/x")
+ os.symlink(ABSTFN+"x", ABSTFN+"y")
+ self.assertEqual(realpath(ABSTFN+"1/../" + basename(ABSTFN) + "y"),
+ ABSTFN + "y")
+ self.assertEqual(realpath(ABSTFN+"1/../" + basename(ABSTFN) + "1"),
+ ABSTFN + "1")
+
+ os.symlink(basename(ABSTFN) + "a/b", ABSTFN+"a")
+ self.assertEqual(realpath(ABSTFN+"a"), ABSTFN+"a/b")
+
+ os.symlink("../" + basename(dirname(ABSTFN)) + "/" +
+ basename(ABSTFN) + "c", ABSTFN+"c")
+ self.assertEqual(realpath(ABSTFN+"c"), ABSTFN+"c")
+
# Test using relative path as well.
os.chdir(dirname(ABSTFN))
self.assertEqual(realpath(basename(ABSTFN)), ABSTFN)
@@ -244,6 +260,39 @@
test_support.unlink(ABSTFN)
test_support.unlink(ABSTFN+"1")
test_support.unlink(ABSTFN+"2")
+ test_support.unlink(ABSTFN+"y")
+ test_support.unlink(ABSTFN+"c")
+
+ def test_realpath_repeated_indirect_symlinks(self):
+ # Issue #6975.
+ try:
+ os.mkdir(ABSTFN)
+ os.symlink('../' + basename(ABSTFN), ABSTFN + '/self')
+ os.symlink('self/self/self', ABSTFN + '/link')
+ self.assertEqual(realpath(ABSTFN + '/link'), ABSTFN)
+ finally:
+ test_support.unlink(ABSTFN + '/self')
+ test_support.unlink(ABSTFN + '/link')
+ safe_rmdir(ABSTFN)
+
+ def test_realpath_deep_recursion(self):
+ depth = 10
+ old_path = abspath('.')
+ try:
+ os.mkdir(ABSTFN)
+ for i in range(depth):
+ os.symlink('/'.join(['%d' % i] * 10), ABSTFN + '/%d' % (i + 1))
+ os.symlink('.', ABSTFN + '/0')
+ self.assertEqual(realpath(ABSTFN + '/%d' % depth), ABSTFN)
+
+ # Test using relative path as well.
+ os.chdir(ABSTFN)
+ self.assertEqual(realpath('%d' % depth), ABSTFN)
+ finally:
+ os.chdir(old_path)
+ for i in range(depth + 1):
+ test_support.unlink(ABSTFN + '/%d' % i)
+ safe_rmdir(ABSTFN)
def test_realpath_resolve_parents(self):
# We also need to resolve any symlinks in the parents of a relative
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -202,6 +202,9 @@
Library
-------
+- Issue #6975: os.path.realpath() now correctly resolves multiple nested
+ symlinks on POSIX platforms.
+
- Issue #17156: pygettext.py now correctly escapes non-ascii characters.
- Issue #7358: cStringIO.StringIO now supports writing to and reading from
--
Repository URL: http://hg.python.org/cpython
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