mirror of
https://github.com/morpheus65535/bazarr
synced 2024-12-22 15:54:26 +00:00
675 lines
22 KiB
Python
675 lines
22 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
|
|
|
|
# Copyright (C) 2003-2017 Nominum, Inc.
|
|
#
|
|
# Permission to use, copy, modify, and distribute this software and its
|
|
# documentation for any purpose with or without fee is hereby granted,
|
|
# provided that the above copyright notice and this permission notice
|
|
# appear in all copies.
|
|
#
|
|
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
|
|
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
|
|
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
|
|
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
|
|
"""Tokenize DNS zone file format"""
|
|
|
|
import io
|
|
import sys
|
|
|
|
import dns.exception
|
|
import dns.name
|
|
import dns.ttl
|
|
|
|
_DELIMITERS = {' ', '\t', '\n', ';', '(', ')', '"'}
|
|
_QUOTING_DELIMITERS = {'"'}
|
|
|
|
EOF = 0
|
|
EOL = 1
|
|
WHITESPACE = 2
|
|
IDENTIFIER = 3
|
|
QUOTED_STRING = 4
|
|
COMMENT = 5
|
|
DELIMITER = 6
|
|
|
|
|
|
class UngetBufferFull(dns.exception.DNSException):
|
|
"""An attempt was made to unget a token when the unget buffer was full."""
|
|
|
|
|
|
class Token:
|
|
"""A DNS zone file format token.
|
|
|
|
ttype: The token type
|
|
value: The token value
|
|
has_escape: Does the token value contain escapes?
|
|
"""
|
|
|
|
def __init__(self, ttype, value='', has_escape=False, comment=None):
|
|
"""Initialize a token instance."""
|
|
|
|
self.ttype = ttype
|
|
self.value = value
|
|
self.has_escape = has_escape
|
|
self.comment = comment
|
|
|
|
def is_eof(self):
|
|
return self.ttype == EOF
|
|
|
|
def is_eol(self):
|
|
return self.ttype == EOL
|
|
|
|
def is_whitespace(self):
|
|
return self.ttype == WHITESPACE
|
|
|
|
def is_identifier(self):
|
|
return self.ttype == IDENTIFIER
|
|
|
|
def is_quoted_string(self):
|
|
return self.ttype == QUOTED_STRING
|
|
|
|
def is_comment(self):
|
|
return self.ttype == COMMENT
|
|
|
|
def is_delimiter(self): # pragma: no cover (we don't return delimiters yet)
|
|
return self.ttype == DELIMITER
|
|
|
|
def is_eol_or_eof(self):
|
|
return self.ttype == EOL or self.ttype == EOF
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, Token):
|
|
return False
|
|
return (self.ttype == other.ttype and
|
|
self.value == other.value)
|
|
|
|
def __ne__(self, other):
|
|
if not isinstance(other, Token):
|
|
return True
|
|
return (self.ttype != other.ttype or
|
|
self.value != other.value)
|
|
|
|
def __str__(self):
|
|
return '%d "%s"' % (self.ttype, self.value)
|
|
|
|
def unescape(self):
|
|
if not self.has_escape:
|
|
return self
|
|
unescaped = ''
|
|
l = len(self.value)
|
|
i = 0
|
|
while i < l:
|
|
c = self.value[i]
|
|
i += 1
|
|
if c == '\\':
|
|
if i >= l: # pragma: no cover (can't happen via get())
|
|
raise dns.exception.UnexpectedEnd
|
|
c = self.value[i]
|
|
i += 1
|
|
if c.isdigit():
|
|
if i >= l:
|
|
raise dns.exception.UnexpectedEnd
|
|
c2 = self.value[i]
|
|
i += 1
|
|
if i >= l:
|
|
raise dns.exception.UnexpectedEnd
|
|
c3 = self.value[i]
|
|
i += 1
|
|
if not (c2.isdigit() and c3.isdigit()):
|
|
raise dns.exception.SyntaxError
|
|
codepoint = int(c) * 100 + int(c2) * 10 + int(c3)
|
|
if codepoint > 255:
|
|
raise dns.exception.SyntaxError
|
|
c = chr(codepoint)
|
|
unescaped += c
|
|
return Token(self.ttype, unescaped)
|
|
|
|
def unescape_to_bytes(self):
|
|
# We used to use unescape() for TXT-like records, but this
|
|
# caused problems as we'd process DNS escapes into Unicode code
|
|
# points instead of byte values, and then a to_text() of the
|
|
# processed data would not equal the original input. For
|
|
# example, \226 in the TXT record would have a to_text() of
|
|
# \195\162 because we applied UTF-8 encoding to Unicode code
|
|
# point 226.
|
|
#
|
|
# We now apply escapes while converting directly to bytes,
|
|
# avoiding this double encoding.
|
|
#
|
|
# This code also handles cases where the unicode input has
|
|
# non-ASCII code-points in it by converting it to UTF-8. TXT
|
|
# records aren't defined for Unicode, but this is the best we
|
|
# can do to preserve meaning. For example,
|
|
#
|
|
# foo\u200bbar
|
|
#
|
|
# (where \u200b is Unicode code point 0x200b) will be treated
|
|
# as if the input had been the UTF-8 encoding of that string,
|
|
# namely:
|
|
#
|
|
# foo\226\128\139bar
|
|
#
|
|
unescaped = b''
|
|
l = len(self.value)
|
|
i = 0
|
|
while i < l:
|
|
c = self.value[i]
|
|
i += 1
|
|
if c == '\\':
|
|
if i >= l: # pragma: no cover (can't happen via get())
|
|
raise dns.exception.UnexpectedEnd
|
|
c = self.value[i]
|
|
i += 1
|
|
if c.isdigit():
|
|
if i >= l:
|
|
raise dns.exception.UnexpectedEnd
|
|
c2 = self.value[i]
|
|
i += 1
|
|
if i >= l:
|
|
raise dns.exception.UnexpectedEnd
|
|
c3 = self.value[i]
|
|
i += 1
|
|
if not (c2.isdigit() and c3.isdigit()):
|
|
raise dns.exception.SyntaxError
|
|
codepoint = int(c) * 100 + int(c2) * 10 + int(c3)
|
|
if codepoint > 255:
|
|
raise dns.exception.SyntaxError
|
|
unescaped += b'%c' % (codepoint)
|
|
else:
|
|
# Note that as mentioned above, if c is a Unicode
|
|
# code point outside of the ASCII range, then this
|
|
# += is converting that code point to its UTF-8
|
|
# encoding and appending multiple bytes to
|
|
# unescaped.
|
|
unescaped += c.encode()
|
|
else:
|
|
unescaped += c.encode()
|
|
return Token(self.ttype, bytes(unescaped))
|
|
|
|
|
|
class Tokenizer:
|
|
"""A DNS zone file format tokenizer.
|
|
|
|
A token object is basically a (type, value) tuple. The valid
|
|
types are EOF, EOL, WHITESPACE, IDENTIFIER, QUOTED_STRING,
|
|
COMMENT, and DELIMITER.
|
|
|
|
file: The file to tokenize
|
|
|
|
ungotten_char: The most recently ungotten character, or None.
|
|
|
|
ungotten_token: The most recently ungotten token, or None.
|
|
|
|
multiline: The current multiline level. This value is increased
|
|
by one every time a '(' delimiter is read, and decreased by one every time
|
|
a ')' delimiter is read.
|
|
|
|
quoting: This variable is true if the tokenizer is currently
|
|
reading a quoted string.
|
|
|
|
eof: This variable is true if the tokenizer has encountered EOF.
|
|
|
|
delimiters: The current delimiter dictionary.
|
|
|
|
line_number: The current line number
|
|
|
|
filename: A filename that will be returned by the where() method.
|
|
|
|
idna_codec: A dns.name.IDNACodec, specifies the IDNA
|
|
encoder/decoder. If None, the default IDNA 2003
|
|
encoder/decoder is used.
|
|
"""
|
|
|
|
def __init__(self, f=sys.stdin, filename=None, idna_codec=None):
|
|
"""Initialize a tokenizer instance.
|
|
|
|
f: The file to tokenize. The default is sys.stdin.
|
|
This parameter may also be a string, in which case the tokenizer
|
|
will take its input from the contents of the string.
|
|
|
|
filename: the name of the filename that the where() method
|
|
will return.
|
|
|
|
idna_codec: A dns.name.IDNACodec, specifies the IDNA
|
|
encoder/decoder. If None, the default IDNA 2003
|
|
encoder/decoder is used.
|
|
"""
|
|
|
|
if isinstance(f, str):
|
|
f = io.StringIO(f)
|
|
if filename is None:
|
|
filename = '<string>'
|
|
elif isinstance(f, bytes):
|
|
f = io.StringIO(f.decode())
|
|
if filename is None:
|
|
filename = '<string>'
|
|
else:
|
|
if filename is None:
|
|
if f is sys.stdin:
|
|
filename = '<stdin>'
|
|
else:
|
|
filename = '<file>'
|
|
self.file = f
|
|
self.ungotten_char = None
|
|
self.ungotten_token = None
|
|
self.multiline = 0
|
|
self.quoting = False
|
|
self.eof = False
|
|
self.delimiters = _DELIMITERS
|
|
self.line_number = 1
|
|
self.filename = filename
|
|
if idna_codec is None:
|
|
idna_codec = dns.name.IDNA_2003
|
|
self.idna_codec = idna_codec
|
|
|
|
def _get_char(self):
|
|
"""Read a character from input.
|
|
"""
|
|
|
|
if self.ungotten_char is None:
|
|
if self.eof:
|
|
c = ''
|
|
else:
|
|
c = self.file.read(1)
|
|
if c == '':
|
|
self.eof = True
|
|
elif c == '\n':
|
|
self.line_number += 1
|
|
else:
|
|
c = self.ungotten_char
|
|
self.ungotten_char = None
|
|
return c
|
|
|
|
def where(self):
|
|
"""Return the current location in the input.
|
|
|
|
Returns a (string, int) tuple. The first item is the filename of
|
|
the input, the second is the current line number.
|
|
"""
|
|
|
|
return (self.filename, self.line_number)
|
|
|
|
def _unget_char(self, c):
|
|
"""Unget a character.
|
|
|
|
The unget buffer for characters is only one character large; it is
|
|
an error to try to unget a character when the unget buffer is not
|
|
empty.
|
|
|
|
c: the character to unget
|
|
raises UngetBufferFull: there is already an ungotten char
|
|
"""
|
|
|
|
if self.ungotten_char is not None:
|
|
# this should never happen!
|
|
raise UngetBufferFull # pragma: no cover
|
|
self.ungotten_char = c
|
|
|
|
def skip_whitespace(self):
|
|
"""Consume input until a non-whitespace character is encountered.
|
|
|
|
The non-whitespace character is then ungotten, and the number of
|
|
whitespace characters consumed is returned.
|
|
|
|
If the tokenizer is in multiline mode, then newlines are whitespace.
|
|
|
|
Returns the number of characters skipped.
|
|
"""
|
|
|
|
skipped = 0
|
|
while True:
|
|
c = self._get_char()
|
|
if c != ' ' and c != '\t':
|
|
if (c != '\n') or not self.multiline:
|
|
self._unget_char(c)
|
|
return skipped
|
|
skipped += 1
|
|
|
|
def get(self, want_leading=False, want_comment=False):
|
|
"""Get the next token.
|
|
|
|
want_leading: If True, return a WHITESPACE token if the
|
|
first character read is whitespace. The default is False.
|
|
|
|
want_comment: If True, return a COMMENT token if the
|
|
first token read is a comment. The default is False.
|
|
|
|
Raises dns.exception.UnexpectedEnd: input ended prematurely
|
|
|
|
Raises dns.exception.SyntaxError: input was badly formed
|
|
|
|
Returns a Token.
|
|
"""
|
|
|
|
if self.ungotten_token is not None:
|
|
token = self.ungotten_token
|
|
self.ungotten_token = None
|
|
if token.is_whitespace():
|
|
if want_leading:
|
|
return token
|
|
elif token.is_comment():
|
|
if want_comment:
|
|
return token
|
|
else:
|
|
return token
|
|
skipped = self.skip_whitespace()
|
|
if want_leading and skipped > 0:
|
|
return Token(WHITESPACE, ' ')
|
|
token = ''
|
|
ttype = IDENTIFIER
|
|
has_escape = False
|
|
while True:
|
|
c = self._get_char()
|
|
if c == '' or c in self.delimiters:
|
|
if c == '' and self.quoting:
|
|
raise dns.exception.UnexpectedEnd
|
|
if token == '' and ttype != QUOTED_STRING:
|
|
if c == '(':
|
|
self.multiline += 1
|
|
self.skip_whitespace()
|
|
continue
|
|
elif c == ')':
|
|
if self.multiline <= 0:
|
|
raise dns.exception.SyntaxError
|
|
self.multiline -= 1
|
|
self.skip_whitespace()
|
|
continue
|
|
elif c == '"':
|
|
if not self.quoting:
|
|
self.quoting = True
|
|
self.delimiters = _QUOTING_DELIMITERS
|
|
ttype = QUOTED_STRING
|
|
continue
|
|
else:
|
|
self.quoting = False
|
|
self.delimiters = _DELIMITERS
|
|
self.skip_whitespace()
|
|
continue
|
|
elif c == '\n':
|
|
return Token(EOL, '\n')
|
|
elif c == ';':
|
|
while 1:
|
|
c = self._get_char()
|
|
if c == '\n' or c == '':
|
|
break
|
|
token += c
|
|
if want_comment:
|
|
self._unget_char(c)
|
|
return Token(COMMENT, token)
|
|
elif c == '':
|
|
if self.multiline:
|
|
raise dns.exception.SyntaxError(
|
|
'unbalanced parentheses')
|
|
return Token(EOF, comment=token)
|
|
elif self.multiline:
|
|
self.skip_whitespace()
|
|
token = ''
|
|
continue
|
|
else:
|
|
return Token(EOL, '\n', comment=token)
|
|
else:
|
|
# This code exists in case we ever want a
|
|
# delimiter to be returned. It never produces
|
|
# a token currently.
|
|
token = c
|
|
ttype = DELIMITER
|
|
else:
|
|
self._unget_char(c)
|
|
break
|
|
elif self.quoting and c == '\n':
|
|
raise dns.exception.SyntaxError('newline in quoted string')
|
|
elif c == '\\':
|
|
#
|
|
# It's an escape. Put it and the next character into
|
|
# the token; it will be checked later for goodness.
|
|
#
|
|
token += c
|
|
has_escape = True
|
|
c = self._get_char()
|
|
if c == '' or (c == '\n' and not self.quoting):
|
|
raise dns.exception.UnexpectedEnd
|
|
token += c
|
|
if token == '' and ttype != QUOTED_STRING:
|
|
if self.multiline:
|
|
raise dns.exception.SyntaxError('unbalanced parentheses')
|
|
ttype = EOF
|
|
return Token(ttype, token, has_escape)
|
|
|
|
def unget(self, token):
|
|
"""Unget a token.
|
|
|
|
The unget buffer for tokens is only one token large; it is
|
|
an error to try to unget a token when the unget buffer is not
|
|
empty.
|
|
|
|
token: the token to unget
|
|
|
|
Raises UngetBufferFull: there is already an ungotten token
|
|
"""
|
|
|
|
if self.ungotten_token is not None:
|
|
raise UngetBufferFull
|
|
self.ungotten_token = token
|
|
|
|
def next(self):
|
|
"""Return the next item in an iteration.
|
|
|
|
Returns a Token.
|
|
"""
|
|
|
|
token = self.get()
|
|
if token.is_eof():
|
|
raise StopIteration
|
|
return token
|
|
|
|
__next__ = next
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
# Helpers
|
|
|
|
def get_int(self, base=10):
|
|
"""Read the next token and interpret it as an unsigned integer.
|
|
|
|
Raises dns.exception.SyntaxError if not an unsigned integer.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
token = self.get().unescape()
|
|
if not token.is_identifier():
|
|
raise dns.exception.SyntaxError('expecting an identifier')
|
|
if not token.value.isdigit():
|
|
raise dns.exception.SyntaxError('expecting an integer')
|
|
return int(token.value, base)
|
|
|
|
def get_uint8(self):
|
|
"""Read the next token and interpret it as an 8-bit unsigned
|
|
integer.
|
|
|
|
Raises dns.exception.SyntaxError if not an 8-bit unsigned integer.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
value = self.get_int()
|
|
if value < 0 or value > 255:
|
|
raise dns.exception.SyntaxError(
|
|
'%d is not an unsigned 8-bit integer' % value)
|
|
return value
|
|
|
|
def get_uint16(self, base=10):
|
|
"""Read the next token and interpret it as a 16-bit unsigned
|
|
integer.
|
|
|
|
Raises dns.exception.SyntaxError if not a 16-bit unsigned integer.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
value = self.get_int(base=base)
|
|
if value < 0 or value > 65535:
|
|
if base == 8:
|
|
raise dns.exception.SyntaxError(
|
|
'%o is not an octal unsigned 16-bit integer' % value)
|
|
else:
|
|
raise dns.exception.SyntaxError(
|
|
'%d is not an unsigned 16-bit integer' % value)
|
|
return value
|
|
|
|
def get_uint32(self, base=10):
|
|
"""Read the next token and interpret it as a 32-bit unsigned
|
|
integer.
|
|
|
|
Raises dns.exception.SyntaxError if not a 32-bit unsigned integer.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
value = self.get_int(base=base)
|
|
if value < 0 or value > 4294967295:
|
|
raise dns.exception.SyntaxError(
|
|
'%d is not an unsigned 32-bit integer' % value)
|
|
return value
|
|
|
|
def get_uint48(self, base=10):
|
|
"""Read the next token and interpret it as a 48-bit unsigned
|
|
integer.
|
|
|
|
Raises dns.exception.SyntaxError if not a 48-bit unsigned integer.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
value = self.get_int(base=base)
|
|
if value < 0 or value > 281474976710655:
|
|
raise dns.exception.SyntaxError(
|
|
'%d is not an unsigned 48-bit integer' % value)
|
|
return value
|
|
|
|
def get_string(self, max_length=None):
|
|
"""Read the next token and interpret it as a string.
|
|
|
|
Raises dns.exception.SyntaxError if not a string.
|
|
Raises dns.exception.SyntaxError if token value length
|
|
exceeds max_length (if specified).
|
|
|
|
Returns a string.
|
|
"""
|
|
|
|
token = self.get().unescape()
|
|
if not (token.is_identifier() or token.is_quoted_string()):
|
|
raise dns.exception.SyntaxError('expecting a string')
|
|
if max_length and len(token.value) > max_length:
|
|
raise dns.exception.SyntaxError("string too long")
|
|
return token.value
|
|
|
|
def get_identifier(self):
|
|
"""Read the next token, which should be an identifier.
|
|
|
|
Raises dns.exception.SyntaxError if not an identifier.
|
|
|
|
Returns a string.
|
|
"""
|
|
|
|
token = self.get().unescape()
|
|
if not token.is_identifier():
|
|
raise dns.exception.SyntaxError('expecting an identifier')
|
|
return token.value
|
|
|
|
def get_remaining(self, max_tokens=None):
|
|
"""Return the remaining tokens on the line, until an EOL or EOF is seen.
|
|
|
|
max_tokens: If not None, stop after this number of tokens.
|
|
|
|
Returns a list of tokens.
|
|
"""
|
|
|
|
tokens = []
|
|
while True:
|
|
token = self.get()
|
|
if token.is_eol_or_eof():
|
|
self.unget(token)
|
|
break
|
|
tokens.append(token)
|
|
if len(tokens) == max_tokens:
|
|
break
|
|
return tokens
|
|
|
|
def concatenate_remaining_identifiers(self):
|
|
"""Read the remaining tokens on the line, which should be identifiers.
|
|
|
|
Raises dns.exception.SyntaxError if a token is seen that is not an
|
|
identifier.
|
|
|
|
Returns a string containing a concatenation of the remaining
|
|
identifiers.
|
|
"""
|
|
s = ""
|
|
while True:
|
|
token = self.get().unescape()
|
|
if token.is_eol_or_eof():
|
|
self.unget(token)
|
|
break
|
|
if not token.is_identifier():
|
|
raise dns.exception.SyntaxError
|
|
s += token.value
|
|
return s
|
|
|
|
def as_name(self, token, origin=None, relativize=False, relativize_to=None):
|
|
"""Try to interpret the token as a DNS name.
|
|
|
|
Raises dns.exception.SyntaxError if not a name.
|
|
|
|
Returns a dns.name.Name.
|
|
"""
|
|
if not token.is_identifier():
|
|
raise dns.exception.SyntaxError('expecting an identifier')
|
|
name = dns.name.from_text(token.value, origin, self.idna_codec)
|
|
return name.choose_relativity(relativize_to or origin, relativize)
|
|
|
|
def get_name(self, origin=None, relativize=False, relativize_to=None):
|
|
"""Read the next token and interpret it as a DNS name.
|
|
|
|
Raises dns.exception.SyntaxError if not a name.
|
|
|
|
Returns a dns.name.Name.
|
|
"""
|
|
|
|
token = self.get()
|
|
return self.as_name(token, origin, relativize, relativize_to)
|
|
|
|
def get_eol_as_token(self):
|
|
"""Read the next token and raise an exception if it isn't EOL or
|
|
EOF.
|
|
|
|
Returns a string.
|
|
"""
|
|
|
|
token = self.get()
|
|
if not token.is_eol_or_eof():
|
|
raise dns.exception.SyntaxError(
|
|
'expected EOL or EOF, got %d "%s"' % (token.ttype,
|
|
token.value))
|
|
return token
|
|
|
|
def get_eol(self):
|
|
return self.get_eol_as_token().value
|
|
|
|
def get_ttl(self):
|
|
"""Read the next token and interpret it as a DNS TTL.
|
|
|
|
Raises dns.exception.SyntaxError or dns.ttl.BadTTL if not an
|
|
identifier or badly formed.
|
|
|
|
Returns an int.
|
|
"""
|
|
|
|
token = self.get().unescape()
|
|
if not token.is_identifier():
|
|
raise dns.exception.SyntaxError('expecting an identifier')
|
|
return dns.ttl.from_text(token.value)
|