首先，因为写的比较长，所以先说声抱歉。
我在学习Python中的符号表，想通过直接访问符号表（不用id()）来提取符号的内存地址。
所以我参考了 Eli Bendersky的 博客。我知道PySTEntry_Type管理着符号表(或者说是它自己)，所以我想通过PySTEntry_Type的内容，不用id()也能找到符号的内存地址。所以，我想利用PySTEntry_Type的内容，不需要id()就可以找到符号的内存地址。
于是我开始分析内存。但是，内存中的值与我所知道的并不一致。
首先，我调查了symtable和_symtable_entry结构。
struct symtable {
PyObject *st_filename; /* name of file being compiled,
decoded from the filesystem encoding */
struct _symtable_entry *st_cur; /* current symbol table entry */
struct _symtable_entry *st_top; /* symbol table entry for module */
PyObject *st_blocks; /* dict: map AST node addresses
* to symbol table entries */
PyObject *st_stack; /* list: stack of namespace info */
PyObject *st_global; /* borrowed ref to st_top->ste_symbols */
int st_nblocks; /* number of blocks used. kept for
consistency with the corresponding
compiler structure */
PyObject *st_private; /* name of current class or NULL */
PyFutureFeatures *st_future; /* modules future features that affect
the symbol table */
int recursion_depth; /* current recursion depth */
int recursion_limit; /* recursion limit */
};
typedef struct _symtable_entry {
PyObject_HEAD
PyObject *ste_id; /* int: key in ste_table->st_blocks */
PyObject *ste_symbols; /* dict: variable names to flags */
PyObject *ste_name; /* string: name of current block */
PyObject *ste_varnames; /* list of function parameters */
PyObject *ste_children; /* list of child blocks */
PyObject *ste_directives;/* locations of global and nonlocal statements */
_Py_block_ty ste_type; /* module, class, or function */
int ste_nested; /* true if block is nested */
unsigned ste_free : 1; /* true if block has free variables */
unsigned ste_child_free : 1; /* true if a child block has free vars,
including free refs to globals */
unsigned ste_generator : 1; /* true if namespace is a generator */
unsigned ste_coroutine : 1; /* true if namespace is a coroutine */
unsigned ste_comprehension : 1; /* true if namespace is a list comprehension */
unsigned ste_varargs : 1; /* true if block has varargs */
unsigned ste_varkeywords : 1; /* true if block has varkeywords */
unsigned ste_returns_value : 1; /* true if namespace uses return with
an argument */
unsigned ste_needs_class_closure : 1; /* for class scopes, true if a
closure over __class__
should be created */
unsigned ste_comp_iter_target : 1; /* true if visiting comprehension target */
int ste_comp_iter_expr; /* non-zero if visiting a comprehension range expression */
int ste_lineno; /* first line of block */
int ste_col_offset; /* offset of first line of block */
int ste_opt_lineno; /* lineno of last exec or import * */
int ste_opt_col_offset; /* offset of last exec or import * */
struct symtable *ste_table;
} PySTEntryObject;
PyAPI_DATA(PyTypeObject) PySTEntry_Type;
而且我用我的代码和gdb提取并组织了PySTEntry_Type中的数据。
extracted data list from PySTEntry_Type
0xa376e0 : PySTEntry_Type (PySTEntry_Object)
0xa3cde0 : PyType_Type
0x74690c : String data (0x74690c : "symtable entry")
0x5782f0 : .text section
0x49b56a : .text section
0x5cb440 : PyObject_GenericGetAttr
0xa301c0 : ????
gdb-peda$ x/100x 0xa376e0
0xa376e0 <PySTEntry_Type>: 0x00000001 0x00000000 0x00a3cde0 0x00000000
0xa376f0 <PySTEntry_Type+16>: 0x00000000 0x00000000 0x0074690c 0x00000000
0xa37700 <PySTEntry_Type+32>: 0x00000068 0x00000000 0x00000000 0x00000000
0xa37710 <PySTEntry_Type+48>: 0x005782f0 0x00000000 0x00000000 0x00000000
0xa37720 <PySTEntry_Type+64>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37730 <PySTEntry_Type+80>: 0x00000000 0x00000000 0x0049b56a 0x00000000
0xa37740 <PySTEntry_Type+96>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37750 <PySTEntry_Type+112>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37760 <PySTEntry_Type+128>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37770 <PySTEntry_Type+144>: 0x005cb440 0x00000000 0x00000000 0x00000000
0xa37780 <PySTEntry_Type+160>: 0x00000000 0x00000000 0x00040000 0x00000000
0xa37790 <PySTEntry_Type+176>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa377a0 <PySTEntry_Type+192>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa377b0 <PySTEntry_Type+208>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa377c0 <PySTEntry_Type+224>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa377d0 <PySTEntry_Type+240>: 0x00a301c0 0x00000000 0x00000000 0x00000000
0xa377e0 <PySTEntry_Type+256>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa377f0 <PySTEntry_Type+272>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37800 <PySTEntry_Type+288>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37810 <PySTEntry_Type+304>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37820 <PySTEntry_Type+320>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37830 <PySTEntry_Type+336>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37840 <PySTEntry_Type+352>: 0x00000000 0x00000000 0x00000000 0x00000000
---Type <return> to continue, or q <return> to quit---
0xa37850 <PySTEntry_Type+368>: 0x00000000 0x00000000 0x00000000 0x00000000
0xa37860 <PySTEntry_Type+384>: 0x00000000 0x00000000 0x00000000 0x00000000
#This is my code
import numpy as np
from ctypes import string_at
from sys import getsizeof
from binascii import hexlify
import os, sys
def print_8byte(addr, size): #Output in 8 bytes for easy viewing
binary = hexlify(string_at(addr, size))
for i in range(int(size/8)):
print(binary[i*16:i*16+16])
if __name__ == "__main__":
print_8byte(0xa376e0, 400) #0xa376e0 is PySTEntry_type
while(1):
addr = int(input("addr : "), 0)
size = int(input("size : "), 0)
print_8byte(addr, size)
hash@hash-desktop:~$ python3 test.py
b'0100000000000000'
b'e0cda30000000000' #0xa3cde0 : PyType_Type
b'0000000000000000'
b'0c69740000000000' #0x74690c : String data (0x74690c : "symtable entry")
b'6800000000000000'
b'0000000000000000'
b'f082570000000000' #0x5782f0 : .text section
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'6ab5490000000000' #0x49b56a : .text section
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'40b45c0000000000' #0x5cb440 : PyObject_GenericGetAttr
b'0000000000000000'
b'0000000000000000'
b'0000040000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'c001a30000000000' #0xa301c0 : ?????
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
b'0000000000000000'
addr :
但是，似乎没有与上述 symtable 和 _symtable_entry 结构匹配的字段。
我是不是误解了PySTEntry_Type？即使我误解了，为什么内存中的值类型和结构的字段不匹配？
对不起，文字和数据太长，谢谢你的阅读。
ps.用gdb和我的代码提取数据没有区别。0xa301c的值如下，可以通过我的代码检查。
addr : 0xa301c0
size : 400
b'884e640000000000'
b'0600000000000000'
b'1000000000000000'
b'0100000000000000'
b'0000000000000000'
b'c4e2730000000000'
b'0600000000000000'
b'2000000000000000'
b'0100000000000000'
b'0000000000000000'
b'fd68740000000000'
b'0600000000000000'
b'1800000000000000'
b'0100000000000000'
b'0000000000000000'
b'ad68740000000000'
.
.
.
.
如果你想检查CPython的符号表，可以用 symtable 模块。你所做的一切都没有意义。
假设你真的在看 PySTEntry_Type 而不是一些完全不相关的虚拟内存部分，你所看到的是虚拟内存中的 物种 为低级符号表条目对象。这个东西是以符号表条目为 int 是为了 12. 它不代表符号表或符号表条目。它包含了关于符号表条目支持的操作的信息。
CPython在字节码编译阶段之后不会保存符号表。你不能检查正在运行的程序的符号表，因为它们不存在。你可以使用 symtable 到 创造 代表Python代码的字符串的符号表。