CAST-Generator

decompiler/structures/pseudo/__init__.py

@@ -32,6 +32,16 @@
     Relation,
     Return,
 )
-from .operations import BinaryOperation, Call, Condition, ListOperation, Operation, OperationType, TernaryExpression, UnaryOperation
+from .operations import (
+    SHORTHANDS,
+    BinaryOperation,
+    Call,
+    Condition,
+    ListOperation,
+    Operation,
+    OperationType,
+    TernaryExpression,
+    UnaryOperation,
+)
 from .typing import CustomType, Float, FunctionTypeDef, Integer, Pointer, Type, TypeParser, UnknownType
 from .z3_logic import Z3Converter

decompiler/util/c2ast/c2ast_generator.py

@@ -0,0 +1,131 @@
+import os
+import sys
+
+sys.path.append(".") # for decompiler package imports (if started from repo root)
+
+import tarfile
+from tempfile import TemporaryDirectory
+
+from c2ast_visitor import PyCNodeVisitor
+from decompiler.task import DecompilerTask
+from pycparser import c_parser, parse_file
+from pycparser.c_ast import Decl, FileAST, FuncDef
+
+FAKE_LIBC_ZIP= os.path.dirname(__file__) + "/fake_libc_include.tar.gz"
+
+
+class C2DeWolfASTGenerator:
+    """ Wrapper for PyCASTVisitor. Usage stuff:
+        - you need to have every variable (including globals) defines, otherwise the code does not work
+            - don't use global strings, they will NOT be resolved 
+        - typedefs are not accounted for, therefore they will yield a CustomType
+        - if you get a parser error from pycparser then throw your input in cpp
+        """
+
+    def __init__(self) -> None:
+        self._visitor = PyCNodeVisitor()
+
+
+    def _getSubAstForFunction(self, head: FileAST, functionName: str) -> FuncDef:
+        """Iterate over every node in the file. Return declarations, typedefs and the requested method to the visitor"""
+        for node in head.ext:
+            # Can be enabled if structs and enums are supported, otherwise it does not work
+            #if isinstance(node, Typedef):
+            #    self._visitor.visit(node) 
+            if isinstance(node, Decl):
+                self._visitor.visit(node)
+            if isinstance(node, FuncDef) and node.decl.name == functionName:
+                return node
+        raise ValueError(f"Function '{functionName}' is not in ast")
+
+
+    def _convertToDeWolfAst(self, pycAst: FuncDef) -> DecompilerTask:
+        """Visit every node in the function and create DecompilerTask"""
+        self._visitor.visit(pycAst)
+        return DecompilerTask(
+            cfg=None,
+            options=None,
+            ast=self._visitor._ast,
+            name=self._visitor._function_name,
+            function_parameters=self._visitor._function_params,
+            function_return_type=self._visitor._return_type,
+        )
+
+
+    def generateFromFile(self, file: str, method: str) -> DecompilerTask:
+        """Generate DeWolf-AST from a given file with methodname"""
+        with tarfile.open(FAKE_LIBC_ZIP, "r:gz") as tgz, TemporaryDirectory() as dir:
+            tgz.extractall(dir)
+            pycAst = parse_file(file, use_cpp=True, cpp_args="-I" + dir + "/fake_libc_include")
+        return self._convertToDeWolfAst(self._getSubAstForFunction(pycAst, method))
+
+
+    def generateFromString(self, code: str, method: str) -> DecompilerTask:
+        """Generate DeWolf-AST from a given string of code with methodname"""
+        parser = c_parser.CParser()
+        pycAst = parser.parse(code, filename="<none>")
+        return self._convertToDeWolfAst(self._getSubAstForFunction(pycAst, method))
+
+
+from decompiler.util.decoration import DecoratedAST
+
+CODE = r"""
+int sub_10b2c() {
+    unsigned int uiVar15;
+    int iVar14;
+    sub_10caf("eax: ");
+    iVar14 = data_12000;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("ebx: ");
+    iVar14 = data_12004;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("ecx: ");
+    iVar14 = data_12008;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("edx: ");
+    iVar14 = data_1200c;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcd);
+    sub_10caf("esi: ");
+    iVar14 = data_12010;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("edi: ");
+    iVar14 = data_12014;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("esp: ");
+    iVar14 = data_12018;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcb);
+    sub_10caf("ebp: ");
+    iVar14 = data_1201c;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcd);
+    sub_10caf("idt: ");
+    uiVar15 = (unsigned short)data_12020;
+    sub_10cc7(uiVar15);
+    sub_10caf(data_10dcb);
+    iVar14 = data_12022;
+    sub_10cc7(iVar14);
+    sub_10caf(data_10dcd);
+    sub_10caf("gdt: ");
+    uiVar15 = (unsigned short)data_12026;
+    sub_10cc7(uiVar15);
+    sub_10caf(data_10dcb);
+    iVar14 = data_12028;
+    sub_10cc7(iVar14);
+    iVar14 = sub_10caf(data_10dcd);
+    return iVar14;
+}
+
+"""
+
+if __name__ == '__main__':
+    #task = C2DeWolfASTGenerator().generateFromString(CODE, "sub_10b2c")
+    task = C2DeWolfASTGenerator().generateFromFile("/home/neoquix/Git-Repos/_DeWolfTesting/main.c", "main")
+    DecoratedAST.from_ast(task._ast).export_plot("/tmp/AST.png")
+    DecoratedAST.print_ascii(task._ast)