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cpython/Lib/zipimport.py
Ronald Oussoren d08fb25769
GH-87235: Make sure "python /dev/fd/9 9</path/to/script.py" works on macOS (#99768) 
On macOS all file descriptors for a particular file in /dev/fd
share the same file offset, that is ``open("/dev/fd/9", "r")`` behaves
more like ``dup(9)`` than a regular open.

This causes problems when a user tries to run "/dev/fd/9" as a script
because zipimport changes the file offset to try to read a zipfile
directory. Therefore change zipimport to reset the file offset after
trying to read the zipfile directory.
2022-11-27 11:56:14 +01:00

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"""zipimport provides support for importing Python modules from Zip archives.
This module exports three objects:
- zipimporter: a class; its constructor takes a path to a Zip archive.
- ZipImportError: exception raised by zipimporter objects. It's a
subclass of ImportError, so it can be caught as ImportError, too.
- _zip_directory_cache: a dict, mapping archive paths to zip directory
info dicts, as used in zipimporter._files.
It is usually not needed to use the zipimport module explicitly; it is
used by the builtin import mechanism for sys.path items that are paths
to Zip archives.
"""
#from importlib import _bootstrap_external
#from importlib import _bootstrap # for _verbose_message
import _frozen_importlib_external as _bootstrap_external
from _frozen_importlib_external import _unpack_uint16, _unpack_uint32
import _frozen_importlib as _bootstrap # for _verbose_message
import _imp # for check_hash_based_pycs
import _io # for open
import marshal # for loads
import sys # for modules
import time # for mktime
import _warnings # For warn()
__all__ = ['ZipImportError', 'zipimporter']
path_sep = _bootstrap_external.path_sep
alt_path_sep = _bootstrap_external.path_separators[1:]
class ZipImportError(ImportError):
pass
# _read_directory() cache
_zip_directory_cache = {}
_module_type = type(sys)
END_CENTRAL_DIR_SIZE = 22
STRING_END_ARCHIVE = b'PK\x05\x06'
MAX_COMMENT_LEN = (1 << 16) - 1
class zipimporter(_bootstrap_external._LoaderBasics):
"""zipimporter(archivepath) -> zipimporter object
Create a new zipimporter instance. 'archivepath' must be a path to
a zipfile, or to a specific path inside a zipfile. For example, it can be
'/tmp/myimport.zip', or '/tmp/myimport.zip/mydirectory', if mydirectory is a
valid directory inside the archive.
'ZipImportError is raised if 'archivepath' doesn't point to a valid Zip
archive.
The 'archive' attribute of zipimporter objects contains the name of the
zipfile targeted.
"""
# Split the "subdirectory" from the Zip archive path, lookup a matching
# entry in sys.path_importer_cache, fetch the file directory from there
# if found, or else read it from the archive.
def __init__(self, path):
if not isinstance(path, str):
raise TypeError(f"expected str, not {type(path)!r}")
if not path:
raise ZipImportError('archive path is empty', path=path)
if alt_path_sep:
path = path.replace(alt_path_sep, path_sep)
prefix = []
while True:
try:
st = _bootstrap_external._path_stat(path)
except (OSError, ValueError):
# On Windows a ValueError is raised for too long paths.
# Back up one path element.
dirname, basename = _bootstrap_external._path_split(path)
if dirname == path:
raise ZipImportError('not a Zip file', path=path)
path = dirname
prefix.append(basename)
else:
# it exists
if (st.st_mode & 0o170000) != 0o100000: # stat.S_ISREG
# it's a not file
raise ZipImportError('not a Zip file', path=path)
break
try:
files = _zip_directory_cache[path]
except KeyError:
files = _read_directory(path)
_zip_directory_cache[path] = files
self._files = files
self.archive = path
# a prefix directory following the ZIP file path.
self.prefix = _bootstrap_external._path_join(*prefix[::-1])
if self.prefix:
self.prefix += path_sep
def find_spec(self, fullname, target=None):
"""Create a ModuleSpec for the specified module.
Returns None if the module cannot be found.
"""
module_info = _get_module_info(self, fullname)
if module_info is not None:
return _bootstrap.spec_from_loader(fullname, self, is_package=module_info)
else:
# Not a module or regular package. See if this is a directory, and
# therefore possibly a portion of a namespace package.
# We're only interested in the last path component of fullname
# earlier components are recorded in self.prefix.
modpath = _get_module_path(self, fullname)
if _is_dir(self, modpath):
# This is possibly a portion of a namespace
# package. Return the string representing its path,
# without a trailing separator.
path = f'{self.archive}{path_sep}{modpath}'
spec = _bootstrap.ModuleSpec(name=fullname, loader=None,
is_package=True)
spec.submodule_search_locations.append(path)
return spec
else:
return None
def get_code(self, fullname):
"""get_code(fullname) -> code object.
Return the code object for the specified module. Raise ZipImportError
if the module couldn't be imported.
"""
code, ispackage, modpath = _get_module_code(self, fullname)
return code
def get_data(self, pathname):
"""get_data(pathname) -> string with file data.
Return the data associated with 'pathname'. Raise OSError if
the file wasn't found.
"""
if alt_path_sep:
pathname = pathname.replace(alt_path_sep, path_sep)
key = pathname
if pathname.startswith(self.archive + path_sep):
key = pathname[len(self.archive + path_sep):]
try:
toc_entry = self._files[key]
except KeyError:
raise OSError(0, '', key)
return _get_data(self.archive, toc_entry)
# Return a string matching __file__ for the named module
def get_filename(self, fullname):
"""get_filename(fullname) -> filename string.
Return the filename for the specified module or raise ZipImportError
if it couldn't be imported.
"""
# Deciding the filename requires working out where the code
# would come from if the module was actually loaded
code, ispackage, modpath = _get_module_code(self, fullname)
return modpath
def get_source(self, fullname):
"""get_source(fullname) -> source string.
Return the source code for the specified module. Raise ZipImportError
if the module couldn't be found, return None if the archive does
contain the module, but has no source for it.
"""
mi = _get_module_info(self, fullname)
if mi is None:
raise ZipImportError(f"can't find module {fullname!r}", name=fullname)
path = _get_module_path(self, fullname)
if mi:
fullpath = _bootstrap_external._path_join(path, '__init__.py')
else:
fullpath = f'{path}.py'
try:
toc_entry = self._files[fullpath]
except KeyError:
# we have the module, but no source
return None
return _get_data(self.archive, toc_entry).decode()
# Return a bool signifying whether the module is a package or not.
def is_package(self, fullname):
"""is_package(fullname) -> bool.
Return True if the module specified by fullname is a package.
Raise ZipImportError if the module couldn't be found.
"""
mi = _get_module_info(self, fullname)
if mi is None:
raise ZipImportError(f"can't find module {fullname!r}", name=fullname)
return mi
# Load and return the module named by 'fullname'.
def load_module(self, fullname):
"""load_module(fullname) -> module.
Load the module specified by 'fullname'. 'fullname' must be the
fully qualified (dotted) module name. It returns the imported
module, or raises ZipImportError if it could not be imported.
Deprecated since Python 3.10. Use exec_module() instead.
"""
msg = ("zipimport.zipimporter.load_module() is deprecated and slated for "
"removal in Python 3.12; use exec_module() instead")
_warnings.warn(msg, DeprecationWarning)
code, ispackage, modpath = _get_module_code(self, fullname)
mod = sys.modules.get(fullname)
if mod is None or not isinstance(mod, _module_type):
mod = _module_type(fullname)
sys.modules[fullname] = mod
mod.__loader__ = self
try:
if ispackage:
# add __path__ to the module *before* the code gets
# executed
path = _get_module_path(self, fullname)
fullpath = _bootstrap_external._path_join(self.archive, path)
mod.__path__ = [fullpath]
if not hasattr(mod, '__builtins__'):
mod.__builtins__ = __builtins__
_bootstrap_external._fix_up_module(mod.__dict__, fullname, modpath)
exec(code, mod.__dict__)
except:
del sys.modules[fullname]
raise
try:
mod = sys.modules[fullname]
except KeyError:
raise ImportError(f'Loaded module {fullname!r} not found in sys.modules')
_bootstrap._verbose_message('import {} # loaded from Zip {}', fullname, modpath)
return mod
def get_resource_reader(self, fullname):
"""Return the ResourceReader for a package in a zip file.
If 'fullname' is a package within the zip file, return the
'ResourceReader' object for the package. Otherwise return None.
"""
try:
if not self.is_package(fullname):
return None
except ZipImportError:
return None
from importlib.readers import ZipReader
return ZipReader(self, fullname)
def invalidate_caches(self):
"""Reload the file data of the archive path."""
try:
self._files = _read_directory(self.archive)
_zip_directory_cache[self.archive] = self._files
except ZipImportError:
_zip_directory_cache.pop(self.archive, None)
self._files = {}
def __repr__(self):
return f'<zipimporter object "{self.archive}{path_sep}{self.prefix}">'
# _zip_searchorder defines how we search for a module in the Zip
# archive: we first search for a package __init__, then for
# non-package .pyc, and .py entries. The .pyc entries
# are swapped by initzipimport() if we run in optimized mode. Also,
# '/' is replaced by path_sep there.
_zip_searchorder = (
(path_sep + '__init__.pyc', True, True),
(path_sep + '__init__.py', False, True),
('.pyc', True, False),
('.py', False, False),
)
# Given a module name, return the potential file path in the
# archive (without extension).
def _get_module_path(self, fullname):
return self.prefix + fullname.rpartition('.')[2]
# Does this path represent a directory?
def _is_dir(self, path):
# See if this is a "directory". If so, it's eligible to be part
# of a namespace package. We test by seeing if the name, with an
# appended path separator, exists.
dirpath = path + path_sep
# If dirpath is present in self._files, we have a directory.
return dirpath in self._files
# Return some information about a module.
def _get_module_info(self, fullname):
path = _get_module_path(self, fullname)
for suffix, isbytecode, ispackage in _zip_searchorder:
fullpath = path + suffix
if fullpath in self._files:
return ispackage
return None
# implementation
# _read_directory(archive) -> files dict (new reference)
#
# Given a path to a Zip archive, build a dict, mapping file names
# (local to the archive, using SEP as a separator) to toc entries.
#
# A toc_entry is a tuple:
#
# (__file__, # value to use for __file__, available for all files,
# # encoded to the filesystem encoding
# compress, # compression kind; 0 for uncompressed
# data_size, # size of compressed data on disk
# file_size, # size of decompressed data
# file_offset, # offset of file header from start of archive
# time, # mod time of file (in dos format)
# date, # mod data of file (in dos format)
# crc, # crc checksum of the data
# )
#
# Directories can be recognized by the trailing path_sep in the name,
# data_size and file_offset are 0.
def _read_directory(archive):
try:
fp = _io.open_code(archive)
except OSError:
raise ZipImportError(f"can't open Zip file: {archive!r}", path=archive)
with fp:
# GH-87235: On macOS all file descriptors for /dev/fd/N share the same
# file offset, reset the file offset after scanning the zipfile diretory
# to not cause problems when some runs 'python3 /dev/fd/9 9<some_script'
start_offset = fp.tell()
try:
try:
fp.seek(-END_CENTRAL_DIR_SIZE, 2)
header_position = fp.tell()
buffer = fp.read(END_CENTRAL_DIR_SIZE)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
if len(buffer) != END_CENTRAL_DIR_SIZE:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
if buffer[:4] != STRING_END_ARCHIVE:
# Bad: End of Central Dir signature
# Check if there's a comment.
try:
fp.seek(0, 2)
file_size = fp.tell()
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}",
path=archive)
max_comment_start = max(file_size - MAX_COMMENT_LEN -
END_CENTRAL_DIR_SIZE, 0)
try:
fp.seek(max_comment_start)
data = fp.read()
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}",
path=archive)
pos = data.rfind(STRING_END_ARCHIVE)
if pos < 0:
raise ZipImportError(f'not a Zip file: {archive!r}',
path=archive)
buffer = data[pos:pos+END_CENTRAL_DIR_SIZE]
if len(buffer) != END_CENTRAL_DIR_SIZE:
raise ZipImportError(f"corrupt Zip file: {archive!r}",
path=archive)
header_position = file_size - len(data) + pos
header_size = _unpack_uint32(buffer[12:16])
header_offset = _unpack_uint32(buffer[16:20])
if header_position < header_size:
raise ZipImportError(f'bad central directory size: {archive!r}', path=archive)
if header_position < header_offset:
raise ZipImportError(f'bad central directory offset: {archive!r}', path=archive)
header_position -= header_size
arc_offset = header_position - header_offset
if arc_offset < 0:
raise ZipImportError(f'bad central directory size or offset: {archive!r}', path=archive)
files = {}
# Start of Central Directory
count = 0
try:
fp.seek(header_position)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
while True:
buffer = fp.read(46)
if len(buffer) < 4:
raise EOFError('EOF read where not expected')
# Start of file header
if buffer[:4] != b'PK\x01\x02':
break # Bad: Central Dir File Header
if len(buffer) != 46:
raise EOFError('EOF read where not expected')
flags = _unpack_uint16(buffer[8:10])
compress = _unpack_uint16(buffer[10:12])
time = _unpack_uint16(buffer[12:14])
date = _unpack_uint16(buffer[14:16])
crc = _unpack_uint32(buffer[16:20])
data_size = _unpack_uint32(buffer[20:24])
file_size = _unpack_uint32(buffer[24:28])
name_size = _unpack_uint16(buffer[28:30])
extra_size = _unpack_uint16(buffer[30:32])
comment_size = _unpack_uint16(buffer[32:34])
file_offset = _unpack_uint32(buffer[42:46])
header_size = name_size + extra_size + comment_size
if file_offset > header_offset:
raise ZipImportError(f'bad local header offset: {archive!r}', path=archive)
file_offset += arc_offset
try:
name = fp.read(name_size)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
if len(name) != name_size:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
# On Windows, calling fseek to skip over the fields we don't use is
# slower than reading the data because fseek flushes stdio's
# internal buffers. See issue #8745.
try:
if len(fp.read(header_size - name_size)) != header_size - name_size:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
if flags & 0x800:
# UTF-8 file names extension
name = name.decode()
else:
# Historical ZIP filename encoding
try:
name = name.decode('ascii')
except UnicodeDecodeError:
name = name.decode('latin1').translate(cp437_table)
name = name.replace('/', path_sep)
path = _bootstrap_external._path_join(archive, name)
t = (path, compress, data_size, file_size, file_offset, time, date, crc)
files[name] = t
count += 1
finally:
fp.seek(start_offset)
_bootstrap._verbose_message('zipimport: found {} names in {!r}', count, archive)
return files
# During bootstrap, we may need to load the encodings
# package from a ZIP file. But the cp437 encoding is implemented
# in Python in the encodings package.
#
# Break out of this dependency by using the translation table for
# the cp437 encoding.
cp437_table = (
# ASCII part, 8 rows x 16 chars
'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'
'\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f'
' !"#$%&\'()*+,-./'
'0123456789:;<=>?'
'@ABCDEFGHIJKLMNO'
'PQRSTUVWXYZ[\\]^_'
'`abcdefghijklmno'
'pqrstuvwxyz{|}~\x7f'
# non-ASCII part, 16 rows x 8 chars
'\xc7\xfc\xe9\xe2\xe4\xe0\xe5\xe7'
'\xea\xeb\xe8\xef\xee\xec\xc4\xc5'
'\xc9\xe6\xc6\xf4\xf6\xf2\xfb\xf9'
'\xff\xd6\xdc\xa2\xa3\xa5\u20a7\u0192'
'\xe1\xed\xf3\xfa\xf1\xd1\xaa\xba'
'\xbf\u2310\xac\xbd\xbc\xa1\xab\xbb'
'\u2591\u2592\u2593\u2502\u2524\u2561\u2562\u2556'
'\u2555\u2563\u2551\u2557\u255d\u255c\u255b\u2510'
'\u2514\u2534\u252c\u251c\u2500\u253c\u255e\u255f'
'\u255a\u2554\u2569\u2566\u2560\u2550\u256c\u2567'
'\u2568\u2564\u2565\u2559\u2558\u2552\u2553\u256b'
'\u256a\u2518\u250c\u2588\u2584\u258c\u2590\u2580'
'\u03b1\xdf\u0393\u03c0\u03a3\u03c3\xb5\u03c4'
'\u03a6\u0398\u03a9\u03b4\u221e\u03c6\u03b5\u2229'
'\u2261\xb1\u2265\u2264\u2320\u2321\xf7\u2248'
'\xb0\u2219\xb7\u221a\u207f\xb2\u25a0\xa0'
)
_importing_zlib = False
# Return the zlib.decompress function object, or NULL if zlib couldn't
# be imported. The function is cached when found, so subsequent calls
# don't import zlib again.
def _get_decompress_func():
global _importing_zlib
if _importing_zlib:
# Someone has a zlib.py[co] in their Zip file
# let's avoid a stack overflow.
_bootstrap._verbose_message('zipimport: zlib UNAVAILABLE')
raise ZipImportError("can't decompress data; zlib not available")
_importing_zlib = True
try:
from zlib import decompress
except Exception:
_bootstrap._verbose_message('zipimport: zlib UNAVAILABLE')
raise ZipImportError("can't decompress data; zlib not available")
finally:
_importing_zlib = False
_bootstrap._verbose_message('zipimport: zlib available')
return decompress
# Given a path to a Zip file and a toc_entry, return the (uncompressed) data.
def _get_data(archive, toc_entry):
datapath, compress, data_size, file_size, file_offset, time, date, crc = toc_entry
if data_size < 0:
raise ZipImportError('negative data size')
with _io.open_code(archive) as fp:
# Check to make sure the local file header is correct
try:
fp.seek(file_offset)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
buffer = fp.read(30)
if len(buffer) != 30:
raise EOFError('EOF read where not expected')
if buffer[:4] != b'PK\x03\x04':
# Bad: Local File Header
raise ZipImportError(f'bad local file header: {archive!r}', path=archive)
name_size = _unpack_uint16(buffer[26:28])
extra_size = _unpack_uint16(buffer[28:30])
header_size = 30 + name_size + extra_size
file_offset += header_size # Start of file data
try:
fp.seek(file_offset)
except OSError:
raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
raw_data = fp.read(data_size)
if len(raw_data) != data_size:
raise OSError("zipimport: can't read data")
if compress == 0:
# data is not compressed
return raw_data
# Decompress with zlib
try:
decompress = _get_decompress_func()
except Exception:
raise ZipImportError("can't decompress data; zlib not available")
return decompress(raw_data, -15)
# Lenient date/time comparison function. The precision of the mtime
# in the archive is lower than the mtime stored in a .pyc: we
# must allow a difference of at most one second.
def _eq_mtime(t1, t2):
# dostime only stores even seconds, so be lenient
return abs(t1 - t2) <= 1
# Given the contents of a .py[co] file, unmarshal the data
# and return the code object. Raises ImportError it the magic word doesn't
# match, or if the recorded .py[co] metadata does not match the source.
def _unmarshal_code(self, pathname, fullpath, fullname, data):
exc_details = {
'name': fullname,
'path': fullpath,
}
flags = _bootstrap_external._classify_pyc(data, fullname, exc_details)
hash_based = flags & 0b1 != 0
if hash_based:
check_source = flags & 0b10 != 0
if (_imp.check_hash_based_pycs != 'never' and
(check_source or _imp.check_hash_based_pycs == 'always')):
source_bytes = _get_pyc_source(self, fullpath)
if source_bytes is not None:
source_hash = _imp.source_hash(
_bootstrap_external._RAW_MAGIC_NUMBER,
source_bytes,
)
_bootstrap_external._validate_hash_pyc(
data, source_hash, fullname, exc_details)
else:
source_mtime, source_size = \
_get_mtime_and_size_of_source(self, fullpath)
if source_mtime:
# We don't use _bootstrap_external._validate_timestamp_pyc
# to allow for a more lenient timestamp check.
if (not _eq_mtime(_unpack_uint32(data[8:12]), source_mtime) or
_unpack_uint32(data[12:16]) != source_size):
_bootstrap._verbose_message(
f'bytecode is stale for {fullname!r}')
return None
code = marshal.loads(data[16:])
if not isinstance(code, _code_type):
raise TypeError(f'compiled module {pathname!r} is not a code object')
return code
_code_type = type(_unmarshal_code.__code__)
# Replace any occurrences of '\r\n?' in the input string with '\n'.
# This converts DOS and Mac line endings to Unix line endings.
def _normalize_line_endings(source):
source = source.replace(b'\r\n', b'\n')
source = source.replace(b'\r', b'\n')
return source
# Given a string buffer containing Python source code, compile it
# and return a code object.
def _compile_source(pathname, source):
source = _normalize_line_endings(source)
return compile(source, pathname, 'exec', dont_inherit=True)
# Convert the date/time values found in the Zip archive to a value
# that's compatible with the time stamp stored in .pyc files.
def _parse_dostime(d, t):
return time.mktime((
(d >> 9) + 1980, # bits 9..15: year
(d >> 5) & 0xF, # bits 5..8: month
d & 0x1F, # bits 0..4: day
t >> 11, # bits 11..15: hours
(t >> 5) & 0x3F, # bits 8..10: minutes
(t & 0x1F) * 2, # bits 0..7: seconds / 2
-1, -1, -1))
# Given a path to a .pyc file in the archive, return the
# modification time of the matching .py file and its size,
# or (0, 0) if no source is available.
def _get_mtime_and_size_of_source(self, path):
try:
# strip 'c' or 'o' from *.py[co]
assert path[-1:] in ('c', 'o')
path = path[:-1]
toc_entry = self._files[path]
# fetch the time stamp of the .py file for comparison
# with an embedded pyc time stamp
time = toc_entry[5]
date = toc_entry[6]
uncompressed_size = toc_entry[3]
return _parse_dostime(date, time), uncompressed_size
except (KeyError, IndexError, TypeError):
return 0, 0
# Given a path to a .pyc file in the archive, return the
# contents of the matching .py file, or None if no source
# is available.
def _get_pyc_source(self, path):
# strip 'c' or 'o' from *.py[co]
assert path[-1:] in ('c', 'o')
path = path[:-1]
try:
toc_entry = self._files[path]
except KeyError:
return None
else:
return _get_data(self.archive, toc_entry)
# Get the code object associated with the module specified by
# 'fullname'.
def _get_module_code(self, fullname):
path = _get_module_path(self, fullname)
import_error = None
for suffix, isbytecode, ispackage in _zip_searchorder:
fullpath = path + suffix
_bootstrap._verbose_message('trying {}{}{}', self.archive, path_sep, fullpath, verbosity=2)
try:
toc_entry = self._files[fullpath]
except KeyError:
pass
else:
modpath = toc_entry[0]
data = _get_data(self.archive, toc_entry)
code = None
if isbytecode:
try:
code = _unmarshal_code(self, modpath, fullpath, fullname, data)
except ImportError as exc:
import_error = exc
else:
code = _compile_source(modpath, data)
if code is None:
# bad magic number or non-matching mtime
# in byte code, try next
continue
modpath = toc_entry[0]
return code, ispackage, modpath
else:
if import_error:
msg = f"module load failed: {import_error}"
raise ZipImportError(msg, name=fullname) from import_error
else:
raise ZipImportError(f"can't find module {fullname!r}", name=fullname)
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