69 lines
2.4 KiB
Python
69 lines
2.4 KiB
Python
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import os
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import tempfile
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from os.path import abspath, dirname, join, normcase, sep
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from django.core.exceptions import SuspiciousFileOperation
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from django.utils.encoding import force_text
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# For backwards-compatibility in Django 2.0
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abspathu = abspath
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def upath(path):
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"""Always return a unicode path (did something for Python 2)."""
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return path
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def npath(path):
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"""
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Always return a native path, that is unicode on Python 3 and bytestring on
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Python 2. Noop for Python 3.
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"""
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return path
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def safe_join(base, *paths):
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"""
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Join one or more path components to the base path component intelligently.
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Return a normalized, absolute version of the final path.
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Raise ValueError if the final path isn't located inside of the base path
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component.
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"""
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base = force_text(base)
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paths = [force_text(p) for p in paths]
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final_path = abspath(join(base, *paths))
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base_path = abspath(base)
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# Ensure final_path starts with base_path (using normcase to ensure we
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# don't false-negative on case insensitive operating systems like Windows),
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# further, one of the following conditions must be true:
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# a) The next character is the path separator (to prevent conditions like
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# safe_join("/dir", "/../d"))
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# b) The final path must be the same as the base path.
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# c) The base path must be the most root path (meaning either "/" or "C:\\")
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if (not normcase(final_path).startswith(normcase(base_path + sep)) and
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normcase(final_path) != normcase(base_path) and
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dirname(normcase(base_path)) != normcase(base_path)):
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raise SuspiciousFileOperation(
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'The joined path ({}) is located outside of the base path '
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'component ({})'.format(final_path, base_path))
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return final_path
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def symlinks_supported():
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"""
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Return whether or not creating symlinks are supported in the host platform
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and/or if they are allowed to be created (e.g. on Windows it requires admin
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permissions).
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"""
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with tempfile.TemporaryDirectory() as temp_dir:
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original_path = os.path.join(temp_dir, 'original')
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symlink_path = os.path.join(temp_dir, 'symlink')
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os.makedirs(original_path)
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try:
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os.symlink(original_path, symlink_path)
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supported = True
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except (OSError, NotImplementedError):
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supported = False
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return supported
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