How to call a C function from within gdb-python method

Question

I want to create a python pretty printer within gdb. I have a hidden data-type xyzHandle in the program I'm trying to debug. I can pull out some information from that handle with a C function; which I can call within the gdb debugger. For example:

xyzHandle object1 = api_get_first_object();

(gdb) print (char *)xyz_get_string(1, object1)

I know I can create a gdb command like 'pn' and use that; but I want to use the build-in python of (gdb) to create a pretty-printer that if it sees 'xyzHandle' it will call 'xyz_get_string(1, object1)' and just print the returned string. That way in (gdb) I can simply type 'print object1' .

我已经阅读了如何创建一个简单的 gdb-python Pretty_printer ，但我不知道如何调用我正在从 python 调试的程序中的函数。

这是我的 xyzHandle 对象的漂亮打印机示例。

# To load this into your gdb session
#
# (gdb) python execfile ("script-name")
#

import gdb.printing

class xyzHandlePrinter:
    """Print an xyzHandle object"""

    def __init__(self, val):
        self.val = val

    def to_string(self):
        return ( str( ???how-do-I-call xyz_get_str???) )


def build_pretty_printer():
    pp = gdb.printing.RegexpCollectionPrettyPrinter("XYZ Library")
    pp.add_printer('xyzHandle Printer', '^xyzHandle', xyzHandlePrinter)
    return pp

gdb.printing.register_pretty_printer(
    gdb.current_objfile(),
    build_pretty_printer())

Answer 1

创建一个漂亮的打印机，如果它看到“xyzHandle”，它将调用“xyz_get_string(1, object1)”并只打印返回的字符串

这通常是一个坏主意：你漂亮的打印机将在“实时”进程中工作，但在事后（core文件）调试中会出错。如果您xyz_get_string在纯 Python 中复制 的功能，通常情况会更好。

我不知道如何调用我正在从 python 调试的程序中的函数。

你可以用gdb.parse_and_eval它。