diff options
| -rw-r--r-- | Doc/library/shutil.rst | 4 | ||||
| -rw-r--r-- | Lib/shutil.py | 45 | ||||
| -rw-r--r-- | Lib/test/test_shutil.py | 57 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2019-06-14-22-37-32.bpo-37260.oecdIf.rst | 2 |
4 files changed, 97 insertions, 11 deletions
diff --git a/Doc/library/shutil.rst b/Doc/library/shutil.rst index d1949d6..d30d289 100644 --- a/Doc/library/shutil.rst +++ b/Doc/library/shutil.rst @@ -343,6 +343,10 @@ Directory and files operations .. versionchanged:: 3.12 Added the *onexc* parameter, deprecated *onerror*. + .. versionchanged:: 3.13 + :func:`!rmtree` now ignores :exc:`FileNotFoundError` exceptions for all + but the top-level path. + .. attribute:: rmtree.avoids_symlink_attacks Indicates whether the current platform and implementation provides a diff --git a/Lib/shutil.py b/Lib/shutil.py index dd93872..93b00d7 100644 --- a/Lib/shutil.py +++ b/Lib/shutil.py @@ -590,23 +590,21 @@ def copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2, dirs_exist_ok=dirs_exist_ok) if hasattr(os.stat_result, 'st_file_attributes'): - def _rmtree_islink(path): - try: - st = os.lstat(path) - return (stat.S_ISLNK(st.st_mode) or - (st.st_file_attributes & stat.FILE_ATTRIBUTE_REPARSE_POINT - and st.st_reparse_tag == stat.IO_REPARSE_TAG_MOUNT_POINT)) - except OSError: - return False + def _rmtree_islink(st): + return (stat.S_ISLNK(st.st_mode) or + (st.st_file_attributes & stat.FILE_ATTRIBUTE_REPARSE_POINT + and st.st_reparse_tag == stat.IO_REPARSE_TAG_MOUNT_POINT)) else: - def _rmtree_islink(path): - return os.path.islink(path) + def _rmtree_islink(st): + return stat.S_ISLNK(st.st_mode) # version vulnerable to race conditions def _rmtree_unsafe(path, onexc): try: with os.scandir(path) as scandir_it: entries = list(scandir_it) + except FileNotFoundError: + return except OSError as err: onexc(os.scandir, path, err) entries = [] @@ -614,6 +612,8 @@ def _rmtree_unsafe(path, onexc): fullname = entry.path try: is_dir = entry.is_dir(follow_symlinks=False) + except FileNotFoundError: + continue except OSError: is_dir = False @@ -624,6 +624,8 @@ def _rmtree_unsafe(path, onexc): # a directory with a symlink after the call to # os.scandir or entry.is_dir above. raise OSError("Cannot call rmtree on a symbolic link") + except FileNotFoundError: + continue except OSError as err: onexc(os.path.islink, fullname, err) continue @@ -631,10 +633,14 @@ def _rmtree_unsafe(path, onexc): else: try: os.unlink(fullname) + except FileNotFoundError: + continue except OSError as err: onexc(os.unlink, fullname, err) try: os.rmdir(path) + except FileNotFoundError: + pass except OSError as err: onexc(os.rmdir, path, err) @@ -643,6 +649,8 @@ def _rmtree_safe_fd(topfd, path, onexc): try: with os.scandir(topfd) as scandir_it: entries = list(scandir_it) + except FileNotFoundError: + return except OSError as err: err.filename = path onexc(os.scandir, path, err) @@ -651,6 +659,8 @@ def _rmtree_safe_fd(topfd, path, onexc): fullname = os.path.join(path, entry.name) try: is_dir = entry.is_dir(follow_symlinks=False) + except FileNotFoundError: + continue except OSError: is_dir = False else: @@ -658,6 +668,8 @@ def _rmtree_safe_fd(topfd, path, onexc): try: orig_st = entry.stat(follow_symlinks=False) is_dir = stat.S_ISDIR(orig_st.st_mode) + except FileNotFoundError: + continue except OSError as err: onexc(os.lstat, fullname, err) continue @@ -665,6 +677,8 @@ def _rmtree_safe_fd(topfd, path, onexc): try: dirfd = os.open(entry.name, os.O_RDONLY, dir_fd=topfd) dirfd_closed = False + except FileNotFoundError: + continue except OSError as err: onexc(os.open, fullname, err) else: @@ -675,6 +689,8 @@ def _rmtree_safe_fd(topfd, path, onexc): os.close(dirfd) dirfd_closed = True os.rmdir(entry.name, dir_fd=topfd) + except FileNotFoundError: + continue except OSError as err: onexc(os.rmdir, fullname, err) else: @@ -692,6 +708,8 @@ def _rmtree_safe_fd(topfd, path, onexc): else: try: os.unlink(entry.name, dir_fd=topfd) + except FileNotFoundError: + continue except OSError as err: onexc(os.unlink, fullname, err) @@ -781,7 +799,12 @@ def rmtree(path, ignore_errors=False, onerror=None, *, onexc=None, dir_fd=None): if dir_fd is not None: raise NotImplementedError("dir_fd unavailable on this platform") try: - if _rmtree_islink(path): + st = os.lstat(path) + except OSError as err: + onexc(os.lstat, path, err) + return + try: + if _rmtree_islink(st): # symlinks to directories are forbidden, see bug #1669 raise OSError("Cannot call rmtree on a symbolic link") except OSError as err: diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py index ae6c681..7ea2496 100644 --- a/Lib/test/test_shutil.py +++ b/Lib/test/test_shutil.py @@ -633,6 +633,63 @@ class TestRmTree(BaseTest, unittest.TestCase): finally: shutil.rmtree(TESTFN, ignore_errors=True) + @unittest.skipIf(sys.platform[:6] == 'cygwin', + "This test can't be run on Cygwin (issue #1071513).") + @os_helper.skip_if_dac_override + @os_helper.skip_unless_working_chmod + def test_rmtree_deleted_race_condition(self): + # bpo-37260 + # + # Test that a file or a directory deleted after it is enumerated + # by scandir() but before unlink() or rmdr() is called doesn't + # generate any errors. + def _onexc(fn, path, exc): + assert fn in (os.rmdir, os.unlink) + if not isinstance(exc, PermissionError): + raise + # Make the parent and the children writeable. + for p, mode in zip(paths, old_modes): + os.chmod(p, mode) + # Remove other dirs except one. + keep = next(p for p in dirs if p != path) + for p in dirs: + if p != keep: + os.rmdir(p) + # Remove other files except one. + keep = next(p for p in files if p != path) + for p in files: + if p != keep: + os.unlink(p) + + os.mkdir(TESTFN) + paths = [TESTFN] + [os.path.join(TESTFN, f'child{i}') + for i in range(6)] + dirs = paths[1::2] + files = paths[2::2] + for path in dirs: + os.mkdir(path) + for path in files: + write_file(path, '') + + old_modes = [os.stat(path).st_mode for path in paths] + + # Make the parent and the children non-writeable. + new_mode = stat.S_IREAD|stat.S_IEXEC + for path in reversed(paths): + os.chmod(path, new_mode) + + try: + shutil.rmtree(TESTFN, onexc=_onexc) + except: + # Test failed, so cleanup artifacts. + for path, mode in zip(paths, old_modes): + try: + os.chmod(path, mode) + except OSError: + pass + shutil.rmtree(TESTFN) + raise + class TestCopyTree(BaseTest, unittest.TestCase): diff --git a/Misc/NEWS.d/next/Library/2019-06-14-22-37-32.bpo-37260.oecdIf.rst b/Misc/NEWS.d/next/Library/2019-06-14-22-37-32.bpo-37260.oecdIf.rst new file mode 100644 index 0000000..a5f2c5e --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-06-14-22-37-32.bpo-37260.oecdIf.rst @@ -0,0 +1,2 @@ +Fixed a race condition in :func:`shutil.rmtree` in which directory entries removed by another process or thread while ``shutil.rmtree()`` is running can cause it to raise FileNotFoundError. Patch by Jeffrey Kintscher. + |