mirror of
https://github.com/borgbackup/borg.git
synced 2026-04-27 09:07:31 -04:00
389e806b68
if there is EPERM just for a single attr, it now still collects the other attrs (previous behaviour: just return empty xattrs dict).
117 lines
5 KiB
Python
117 lines
5 KiB
Python
"""A basic extended attributes (xattr) implementation for Linux, FreeBSD and MacOS X."""
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import errno
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import os
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import tempfile
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from .logger import create_logger
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logger = create_logger()
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from .platform import listxattr, getxattr, setxattr, ENOATTR
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XATTR_FAKEROOT = True # fakeroot with xattr support required (>= 1.20.2?)
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def is_enabled(path=None):
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"""Determine if xattr is enabled on the filesystem
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"""
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with tempfile.NamedTemporaryFile(dir=path, prefix='borg-tmp') as fd:
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try:
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setxattr(fd.fileno(), b'user.name', b'value')
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except OSError:
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return False
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return getxattr(fd.fileno(), b'user.name') == b'value'
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def get_all(path, follow_symlinks=False):
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"""
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Return all extended attributes on *path* as a mapping.
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*path* can either be a path (str or bytes) or an open file descriptor (int).
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*follow_symlinks* indicates whether symlinks should be followed
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and only applies when *path* is not an open file descriptor.
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The returned mapping maps xattr names (bytes) to values (bytes or None).
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None indicates, as a xattr value, an empty value, i.e. a value of length zero.
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"""
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if isinstance(path, str):
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path = os.fsencode(path)
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result = {}
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try:
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names = listxattr(path, follow_symlinks=follow_symlinks)
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for name in names:
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try:
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# xattr name is a bytes object, we directly use it.
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# if we get an empty xattr value (b''), we store None into the result dict -
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# borg always did it like that...
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result[name] = getxattr(path, name, follow_symlinks=follow_symlinks) or None
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except OSError as e:
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name_str = name.decode()
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if isinstance(path, int):
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path_str = '<FD %d>' % path
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else:
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path_str = os.fsdecode(path)
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if e.errno == ENOATTR:
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# if we get ENOATTR, a race has happened: xattr names were deleted after list.
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# we just ignore the now missing ones. if you want consistency, do snapshots.
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pass
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elif e.errno == errno.EPERM:
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# we were not permitted to read this attribute, still can continue trying to read others
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logger.warning('%s: Operation not permitted when reading extended attribute %s' % (
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path_str, name_str))
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else:
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raise
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except OSError as e:
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if e.errno in (errno.ENOTSUP, errno.EPERM):
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# if xattrs are not supported on the filesystem, we give up.
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# EPERM might be raised by listxattr.
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pass
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else:
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raise
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return result
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def set_all(path, xattrs, follow_symlinks=False):
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"""
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Set all extended attributes on *path* from a mapping.
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*path* can either be a path (str or bytes) or an open file descriptor (int).
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*follow_symlinks* indicates whether symlinks should be followed
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and only applies when *path* is not an open file descriptor.
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*xattrs* is mapping maps xattr names (bytes) to values (bytes or None).
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None indicates, as a xattr value, an empty value, i.e. a value of length zero.
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Return warning status (True means a non-fatal exception has happened and was dealt with).
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"""
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if isinstance(path, str):
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path = os.fsencode(path)
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warning = False
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for k, v in xattrs.items():
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try:
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# the key k is a bytes object due to msgpack unpacking it as such.
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# if we have a None value, it means "empty", so give b'' to setxattr in that case:
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setxattr(path, k, v or b'', follow_symlinks=follow_symlinks)
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except OSError as e:
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warning = True
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k_str = k.decode()
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if isinstance(path, int):
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path_str = '<FD %d>' % path
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else:
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path_str = os.fsdecode(path)
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if e.errno == errno.E2BIG:
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logger.warning('%s: Value or key of extended attribute %s is too big for this filesystem' % (
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path_str, k_str))
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elif e.errno == errno.ENOTSUP:
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logger.warning('%s: Extended attributes are not supported on this filesystem' % path_str)
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elif e.errno == errno.EACCES:
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# permission denied to set this specific xattr (this may happen related to security.* keys)
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logger.warning('%s: Permission denied when setting extended attribute %s' % (path_str, k_str))
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elif e.errno == errno.ENOSPC:
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# ext4 reports ENOSPC when trying to set an xattr with >4kiB while ext4 can only support 4kiB xattrs
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# (in this case, this is NOT a "disk full" error, just a ext4 limitation).
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logger.warning('%s: No space left on device while setting extended attribute %s (len = %d)' % (
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path_str, k_str, len(v)))
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else:
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raise
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return warning
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