borg/src/borg/constants.py

159 lines
6.5 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# this set must be kept complete, otherwise the RobustUnpacker might malfunction:
ITEM_KEYS = frozenset(['path', 'source', 'rdev', 'chunks', 'chunks_healthy', 'hardlink_master',
'mode', 'user', 'group', 'uid', 'gid', 'mtime', 'atime', 'ctime', 'birthtime', 'size',
'xattrs', 'bsdflags', 'acl_nfs4', 'acl_access', 'acl_default', 'acl_extended',
'part'])
# this is the set of keys that are always present in items:
REQUIRED_ITEM_KEYS = frozenset(['path', 'mtime', ])
# this set must be kept complete, otherwise rebuild_manifest might malfunction:
ARCHIVE_KEYS = frozenset(['version', 'name', 'items', 'cmdline', 'hostname', 'username', 'time', 'time_end',
'comment', 'chunker_params',
'recreate_cmdline',
'recreate_source_id', 'recreate_args', 'recreate_partial_chunks', # used in 1.1.0b1 .. b2
'size', 'csize', 'nfiles', 'size_parts', 'csize_parts', 'nfiles_parts', ])
# this is the set of keys that are always present in archives:
REQUIRED_ARCHIVE_KEYS = frozenset(['version', 'name', 'items', 'cmdline', 'time', ])
# default umask, overridden by --umask, defaults to read/write only for owner
UMASK_DEFAULT = 0o077
# default file mode to store stdin data, defaults to read/write for owner and group
# forcing to 0o100XXX later
STDIN_MODE_DEFAULT = 0o660
CACHE_TAG_NAME = 'CACHEDIR.TAG'
CACHE_TAG_CONTENTS = b'Signature: 8a477f597d28d172789f06886806bc55'
# A large, but not unreasonably large segment size. Always less than 2 GiB (for legacy file systems). We choose
# 500 MiB which means that no indirection from the inode is needed for typical Linux file systems.
# Note that this is a soft-limit and can be exceeded (worst case) by a full maximum chunk size and some metadata
# bytes. That's why it's 500 MiB instead of 512 MiB.
DEFAULT_MAX_SEGMENT_SIZE = 500 * 1024 * 1024
# 20 MiB minus 41 bytes for a Repository header (because the "size" field in the Repository includes
# the header, and the total size was set to 20 MiB).
MAX_DATA_SIZE = 20971479
# MAX_OBJECT_SIZE = <20 MiB (MAX_DATA_SIZE) + 41 bytes for a Repository PUT header, which consists of
# a 1 byte tag ID, 4 byte CRC, 4 byte size and 32 bytes for the ID.
MAX_OBJECT_SIZE = MAX_DATA_SIZE + 41 # see LoggedIO.put_header_fmt.size assertion in repository module
assert MAX_OBJECT_SIZE == 20 * 1024 * 1024
# repo config max_segment_size value must be below this limit to stay within uint32 offsets:
MAX_SEGMENT_SIZE_LIMIT = 2 ** 32 - MAX_OBJECT_SIZE
# have one all-zero bytes object
# we use it at all places where we need to detect or create all-zero buffers
zeros = bytes(MAX_DATA_SIZE)
# borg.remote read() buffer size
BUFSIZE = 10 * 1024 * 1024
# to use a safe, limited unpacker, we need to set a upper limit to the archive count in the manifest.
# this does not mean that you can always really reach that number, because it also needs to be less than
# MAX_DATA_SIZE or it will trigger the check for that.
MAX_ARCHIVES = 400000
# repo.list() / .scan() result count limit the borg client uses
LIST_SCAN_LIMIT = 100000
DEFAULT_SEGMENTS_PER_DIR = 1000
FD_MAX_AGE = 4 * 60 # 4 minutes
CHUNK_MIN_EXP = 19 # 2**19 == 512kiB
CHUNK_MAX_EXP = 23 # 2**23 == 8MiB
HASH_WINDOW_SIZE = 0xfff # 4095B
HASH_MASK_BITS = 21 # results in ~2MiB chunks statistically
# chunker algorithms
CH_BUZHASH = 'buzhash'
CH_FIXED = 'fixed'
# defaults, use --chunker-params to override
CHUNKER_PARAMS = (CH_BUZHASH, CHUNK_MIN_EXP, CHUNK_MAX_EXP, HASH_MASK_BITS, HASH_WINDOW_SIZE)
# chunker params for the items metadata stream, finer granularity
ITEMS_CHUNKER_PARAMS = (CH_BUZHASH, 15, 19, 17, HASH_WINDOW_SIZE)
# normal on-disk data, allocated (but not written, all zeros), not allocated hole (all zeros)
CH_DATA, CH_ALLOC, CH_HOLE = 0, 1, 2
# operating mode of the files cache (for fast skipping of unchanged files)
DEFAULT_FILES_CACHE_MODE_UI = 'ctime,size,inode' # default for "borg create" command (CLI UI)
DEFAULT_FILES_CACHE_MODE = 'd' # most borg commands do not use the files cache at all (disable)
# return codes returned by borg command
# when borg is killed by signal N, rc = 128 + N
EXIT_SUCCESS = 0 # everything done, no problems
EXIT_WARNING = 1 # reached normal end of operation, but there were issues
EXIT_ERROR = 2 # terminated abruptly, did not reach end of operation
EXIT_SIGNAL_BASE = 128 # terminated due to signal, rc = 128 + sig_no
# never use datetime.isoformat(), it is evil. always use one of these:
# datetime.strftime(ISO_FORMAT) # output always includes .microseconds
# datetime.strftime(ISO_FORMAT_NO_USECS) # output never includes microseconds
ISO_FORMAT_NO_USECS = '%Y-%m-%dT%H:%M:%S'
ISO_FORMAT = ISO_FORMAT_NO_USECS + '.%f'
DASHES = '-' * 78
PBKDF2_ITERATIONS = 100000
# https://www.rfc-editor.org/rfc/rfc9106.html#section-4-6.2
ARGON2_ARGS = {'time_cost': 3, 'memory_cost': 2**16, 'parallelism': 4, 'type': 'id'}
ARGON2_SALT_BYTES = 16
# Maps the CLI argument to our internal identifier for the format
KEY_ALGORITHMS = {
# encrypt-and-MAC, kdf: PBKDF2(HMACSHA256), encryption: AES256-CTR, authentication: HMAC-SHA256
'pbkdf2': 'sha256',
# encrypt-then-MAC, kdf: argon2, encryption: AES256-CTR, authentication: HMAC-SHA256
'argon2': 'argon2 aes256-ctr hmac-sha256',
}
class KeyBlobStorage:
NO_STORAGE = 'no_storage'
KEYFILE = 'keyfile'
REPO = 'repository'
class KeyType:
# legacy crypto
# upper 4 bits are ciphersuite, 0 == legacy AES-CTR
KEYFILE = 0x00
# repos with PASSPHRASE mode could not be created any more since borg 1.0, see #97.
# in borg 1.3 all of its code and also the "borg key migrate-to-repokey" command was removed.
# if you still need to, you can use "borg key migrate-to-repokey" with borg 1.0, 1.1 and 1.2.
# Nowadays, we just dispatch this to RepoKey and assume the passphrase was migrated to a repokey.
PASSPHRASE = 0x01 # legacy, attic and borg < 1.0
PLAINTEXT = 0x02
REPO = 0x03
BLAKE2KEYFILE = 0x04
BLAKE2REPO = 0x05
BLAKE2AUTHENTICATED = 0x06
AUTHENTICATED = 0x07
# new crypto
# upper 4 bits are ciphersuite, lower 4 bits are keytype
AESOCBKEYFILE = 0x10
AESOCBREPO = 0x11
CHPOKEYFILE = 0x20
CHPOREPO = 0x21
BLAKE2AESOCBKEYFILE = 0x30
BLAKE2AESOCBREPO = 0x31
BLAKE2CHPOKEYFILE = 0x40
BLAKE2CHPOREPO = 0x41
REPOSITORY_README = """This is a Borg Backup repository.
See https://borgbackup.readthedocs.io/
"""
CACHE_README = """This is a Borg Backup cache.
See https://borgbackup.readthedocs.io/
"""