crashpad/util/mach/mig.py
Mark Mentovai 5a0b7827ff Run mig to generate the exc and mach_exc interfaces.
mach_exc is necessary because libSystem doesn’t contain this at all. exc
is necessary too, however: the copy in libSystem relies on the server
callbacks being externally defined symbols, which is cheesey.
Additionally, some Crashpad code wants to call internal validation
(“check”) routines that are not normally accessible to outside callers
via the copy of exc in libSystem, but they are made accessible here by
processing mig’s output in this Python script.

R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/541213002
2014-09-05 13:27:06 -04:00

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#!/usr/bin/env python
# coding: utf-8
# Copyright 2014 The Crashpad Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import re
import subprocess
import sys
def FixUserImplementation(implementation):
"""Rewrites a MIG-generated user implementation (.c) file.
Rewrites the file at |implementation| by adding “__attribute__((unused))” to
the definition of any structure typedefed as “__Reply” by searching for the
pattern unique to those structure definitions. These structures are in fact
unused in the user implementation file, and this will trigger a
-Wunused-local-typedefs warning in gcc unless removed or marked with the
“unused” attribute.
"""
file = open(implementation, 'r+')
contents = file.read()
pattern = re.compile('^(\t} __Reply);$', re.MULTILINE)
contents = pattern.sub(r'\1 __attribute__((unused));', contents)
file.seek(0)
file.truncate()
file.write(contents)
file.close()
def FixServerImplementation(implementation):
"""Rewrites a MIG-generated server implementation (.c) file.
Rewrites the file at |implementation| by replacing “mig_internal” with
“mig_external” on functions that begin with “__MIG_check__”. This makes these
functions available to other callers outside this file from a linkage
perspective. It then returns, as a list of lines, declarations that can be
added to a header file, so that other files that include that header file will
have access to these declarations from a compilation perspective.
"""
file = open(implementation, 'r+')
contents = file.read()
# Find interesting declarations.
declaration_pattern = \
re.compile('^mig_internal (kern_return_t __MIG_check__.*)$',
re.MULTILINE)
declarations = declaration_pattern.findall(contents)
# Remove “__attribute__((__unused__))” from the declarations, and call them
# “mig_external” or “extern” depending on whether “mig_external” is defined.
attribute_pattern = re.compile(r'__attribute__\(\(__unused__\)\) ')
declarations = ['#ifdef mig_external\nmig_external\n#else\nextern\n#endif\n' +
attribute_pattern.sub('', x) +
';\n' for x in declarations]
# Rewrite the declarations in this file as “mig_external”.
contents = declaration_pattern.sub(r'mig_external \1', contents);
file.seek(0)
file.truncate()
file.write(contents)
file.close()
return declarations
def FixHeader(header, declarations=[]):
"""Rewrites a MIG-generated header (.h) file.
Rewrites the file at |header| by placing it inside an “extern "C"” block, so
that it declares things properly when included by a C++ compilation unit.
|declarations| can be a list of additional declarations to place inside the
“extern "C"” block after the original contents of |header|.
"""
file = open(header, 'r+')
contents = file.read()
declarations_text = ''.join(declarations)
contents = '''\
#ifdef __cplusplus
extern "C" {
#endif
%s
%s
#ifdef __cplusplus
}
#endif
''' % (contents, declarations_text)
file.seek(0)
file.truncate()
file.write(contents)
file.close()
def main(args):
assert len(args) == 5
(defs_file, user_c, server_c, user_h, server_h) = args
subprocess.check_call(['mig',
'-user', user_c,
'-server', server_c,
'-header', user_h,
'-sheader', server_h,
defs_file])
FixUserImplementation(user_c)
server_declarations = FixServerImplementation(server_c)
FixHeader(user_h)
FixHeader(server_h, server_declarations)
if __name__ == '__main__':
sys.exit(main(sys.argv[1:]))