tools: add headerparser as a tool to assist in writing system call descriptions

The tool can be found inside tools/syz-headerparser. Details on how to use
headerparser can be found inside docs/headerparser_usage.md.

1 files changed, 142 insertions, 0 deletions

diff --git a/tools/syz-headerparser/headerlib/header_preprocessor.py b/tools/syz-headerparser/headerlib/header_preprocessor.py
new file mode 100644
index 000000000..429d9688e
--- /dev/null
+++ b/tools/syz-headerparser/headerlib/header_preprocessor.py
@@ -0,0 +1,142 @@
+# Copyright 2017 syzkaller project authors. All rights reserved.
+# Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+'''
+This module provides classes which implement header file preprocessing.
+'''
+
+import logging
+import ntpath
+import os
+import subprocess
+import tempfile
+import traceback
+
+import pycparser
+
+template = '''
+#include <stdbool.h>
+#define _GNU_SOURCE             /* See feature_test_macros(7) */
+
+// ------ MAKE PYCPARSER HAPPY ------
+#define __attribute__(...)
+#define __inline inline
+#define __restrict
+#define __extension__
+// #define __sighandler_t int
+#define __user
+
+#define __asm__(...)
+#define __volatile__(...)
+#define __signed__ signed
+#define __int128_t unsigned long long // Hacky
+#define __alignof__(...) 0
+
+#define INIT // regex
+typedef unsigned int size_t;
+// ------ MAKE PYCPARSER HAPPY ------
+
+#include <stdint.h>
+%(include_lines)s
+%(header_file_includes)s
+'''
+
+
+class HeaderFilePreprocessorException(Exception):
+    '''Exceptions raised from HeaderFileParser. '''
+    pass
+
+
+class HeaderFilePreprocessor(object):
+    '''
+    Given a C header filename, perform pre-processing and return an
+    ast that can be used for further processing.
+
+    Usage :
+
+    >>> import tempfile
+    >>> t = tempfile.NamedTemporaryFile()
+    >>> contents = """
+    ... struct ARRAY_OF_POINTERS_CONTAINER {
+    ... unsigned int *ptr[10];
+    ... int **n;
+    ... };
+    ...
+    ... struct ARRAY_CONTAINER {
+    ... int g[10];
+    ... int h[20][30];
+    ... };
+    ...
+    ... struct REGULAR_STRUCT {
+    ... int x;
+    ... char *y;
+    ... void *ptr;
+    ... };
+    ...
+    ... struct STRUCT_WITH_STRUCT_PTR {
+    ... struct REGULAR_STRUCT *struct_ptr;
+    ... int z;
+    ... };
+    ... """
+    >>> t.write(contents) ; t.flush()
+    >>> h = HeaderFilePreprocessor([t.name])
+    >>> ast = h.get_ast()
+    >>> print type(ast)
+    <class 'pycparser.c_ast.FileAST'>
+    '''
+
+    def __init__(self, filenames, include_lines='', loglvl=logging.INFO):
+        self.filenames = filenames
+        self.include_lines = include_lines
+        self._setuplogging(loglvl)
+        self._mktempfiles()
+        self._copyfiles()
+        self._gcc_preprocess()
+
+    def execute(self, cmd):
+        self.logger.debug('HeaderFilePreprocessor.execute: %s', cmd)
+        p = subprocess.Popen(cmd, shell=True)
+        try:
+            os.waitpid(p.pid, 0)
+        except OSError as exception:
+            raise HeaderFilePreprocessorException(exception)
+
+    def _setuplogging(self, loglvl):
+        self.logger = logging.getLogger(self.__class__.__name__)
+        formatter = logging.Formatter('DEBUG:%(name)s:%(message)s')
+        sh = logging.StreamHandler()
+        sh.setFormatter(formatter)
+        sh.setLevel(loglvl)
+        self.logger.addHandler(sh)
+        self.logger.setLevel(loglvl)
+
+    def _copyfiles(self):
+        self.execute('cp %s %s' % (' '.join(self.filenames), self.tempdir))
+
+    def _mktempfiles(self):
+        self.tempdir = tempfile.mkdtemp()
+        self.temp_sourcefile = os.path.join(self.tempdir, 'source.c')
+        self.temp_objectfile = os.path.join(self.tempdir, 'source.o')
+        self.logger.debug(('HeaderFilePreprocessor._mktempfiles: sourcefile=%s'
+                           'objectfile=%s'), self.temp_sourcefile, self.temp_objectfile)
+
+        header_file_includes = ''
+        include_lines = self.include_lines
+        for name in self.filenames:
+            header_file_includes = '%s#include "%s"\n' % (header_file_includes,
+                                                          ntpath.basename(name))
+
+        open(self.temp_sourcefile, 'w').write(template % (locals()))
+
+    def _gcc_preprocess(self):
+        self.execute('gcc -I. -E -P -c %s > %s'
+                                        % (self.temp_sourcefile, self.temp_objectfile))
+
+    def _get_ast(self):
+        return pycparser.parse_file(self.temp_objectfile)
+
+    def get_ast(self):
+        try:
+            return self._get_ast()
+        except pycparser.plyparser.ParseError as e:
+            raise HeaderFilePreprocessorException(e)