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@cmsj cmsj/lol.py
Last active Apr 14, 2018

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#!/usr/bin/env python
"""
Enforce the usage of Hammerspoon's Lua stack guarding macros
"""
from __future__ import print_function
import sys
from clang.cindex import Config
from clang.cindex import Index
from clang.cindex import CursorKind
from clang.cindex import TypeKind
FILENAME = "Unknown"
def is_function(node):
"""Is the given node a C function or an ObjC method?"""
return node.kind in [CursorKind.FUNCTION_DECL,
CursorKind.OBJC_INSTANCE_METHOD_DECL,
CursorKind.OBJC_CLASS_METHOD_DECL]
def is_implementation(node):
"""Is the given node an ObjC @implementation?"""
return node.kind == CursorKind.OBJC_IMPLEMENTATION_DECL
def is_luastate_param(node):
"""Is the given node a lua_State parameter?"""
# We need the underlying text tokens to detect the typedef 'lua_State'
tokens = [x.spelling for x in node.get_tokens()]
try:
return node.type.kind == TypeKind.POINTER and \
tokens[0] == 'lua_State'
except IndexError:
return False
def is_lua_call(node):
"""Is the given node a Lua->C call?"""
params = [x for x in node.get_children() if x.kind == CursorKind.PARM_DECL]
return node.result_type.kind == TypeKind.INT and len(params) == 1 and \
is_luastate_param(params[0])
def build_tree(node, recurse=True):
"""Build a tree below a node"""
if recurse:
children = [build_tree(c) for c in node.get_children()]
else:
children = ['skipped']
return {'node': node,
'kind': node.kind,
'spelling': node.spelling,
'tokens': ' '.join([x.spelling for x in node.get_tokens()]),
'children': children}
def contains_lua_calls(item):
"""Check if a node contains any Lua API calls"""
if 'lua_' in item['tokens']:
return True
if 'luaL_' in item['tokens']:
return True
if 'LuaSkin' in item['tokens']:
return True
return False
def main(filename):
"""Main function"""
functions = []
tree = []
Config.set_library_file(
"/Library/Developer/CommandLineTools/usr/lib/libclang.dylib")
index = Index.create()
ast = index.parse(None, [filename])
if not ast:
print("Unable to parse file")
sys.exit(1)
# Step 1: Find all the C/ObjC functions
functions = [x for x in ast.cursor.get_children() if is_function(x)]
# Step 1a: Add in ObjC class methods
for item in ast.cursor.get_children():
if is_implementation(item):
functions += [x for x in item.get_children() if is_function(x)]
# Step 2: Filter out all of the functions that are Lua->C calls
functions = [x for x in functions if not is_lua_call(x)]
# Step 3: Recursively walk the remaining functions
tree = [build_tree(x, False) for x in functions]
# Step 4: Filter the functions down to those which contain Lua calls
tree = [x for x in tree if contains_lua_calls(x)]
for thing in tree:
stacktxt = "NO STACKGUARD"
hasstackentry = "_lua_stackguard_entry" in thing['tokens']
hasstackexit = "_lua_stackguard_exit" in thing['tokens']
if hasstackentry and hasstackexit:
continue
if hasstackentry and not hasstackexit:
stacktxt = "STACK ENTRY, BUT NO EXIT"
if hasstackexit and not hasstackentry:
stacktxt = "STACK EXIT, BUT NO ENTRY (THIS IS A CRASH)"
print(u"%s :: %s :: %s" % (filename, thing['spelling'], stacktxt))
if __name__ == '__main__':
main(sys.argv[1])
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