swig c++ to python with openssl/bn.h

Question

我正在尝试使用 SWIG 创建一个 *.so 文件以便在 Python 中进一步使用。特别是我正在使用 openssl 中的一些库（例如 opensll/bn.h）。但不知何故 return 错误 ImportError: [...]/auxchash.so: undefined symbol: BN_bn2hex.

我有 file.cpp, auxchash.cpp:

#include auxchash.h

int keygen(int bits, char *p, char *q, char *g, char *hk, char *tk){
  BN_CTX *ctx = BN_CTX_new();
  BIGNUM *bn_p = BN_new();
  BIGNUM *bn_q = BN_new();
  BIGNUM *bn_g = BN_new();
  BIGNUM *bn_hk = BN_new();
  BIGNUM *bn_tk = BN_new();
  BIGNUM *bn_two = BN_new();

  BN_CTX_init(ctx);

  BN_dec2bn(&bn_two, "2"); //initialize a BIGNUM with value 2

  //on non-unix platform needs to initialize the PRNG with randomness
  //or BN_generate_prime_ex may fail

  //computing the safe prime p and q = (p-1)/2
  BN_generate_prime_ex(bn_p, bits, 1, NULL, NULL, NULL);
  BN_sub(bn_q, bn_p, BN_value_one());
  BN_div(bn_q, NULL, bn_q, bn_two, ctx);

  //finding the generator g (for the group QR_p)
  BN_rand_range(bn_g, bn_p);
  BN_mod_exp(bn_g, bn_g, bn_two, bn_p, ctx);

  //choosing the keys hk and tk
  BN_rand_range(bn_tk, bn_q);
  BN_mod_exp(bn_hk, bn_g, bn_tk, bn_p, ctx);

  //converting from BIGNUM to hex
  p = BN_bn2hex(bn_p);
  q = BN_bn2hex(bn_q);
  g = BN_bn2hex(bn_g);
  hk = BN_bn2hex(bn_hk);
  tk = BN_bn2hex(bn_tk);

  //freeing the resources
  BN_CTX_free(ctx);
  BN_free(bn_two);
  BN_free(bn_p);
  BN_free(bn_q);
  BN_free(bn_g);
  BN_free(bn_hk);
  BN_clear_free(bn_tk);

  return 0;
}

file.h,auxchash.h:

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<openssl/bn.h>
#include<openssl/sha.h>
#include<openssl/rand.h>

int keygen(int bits, char *p, char *q, char *g, char *hk, char *tk);

swig模块的file.i，auxchash.i：

%module auxchash
%{
#define SWIG_FILE_WITH_INIT
#include "auxchash.h"
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<openssl/bn.h>
#include<openssl/sha.h>
#include<openssl/rand.h>
%}

%include "typemaps.i"
%include "cstring.i"

%cstring_bounded_output(char *p, 1024);
%cstring_bounded_output(char *q, 1024);
%cstring_bounded_output(char *g, 1024);
%cstring_bounded_output(char *hk, 1024);
%cstring_bounded_output(char *tk, 1024);
extern int keygen(int bits, char *p, char *q, char *g, char *hk, char *tk);

最后一个文件 setup.py 来创建所有需要的 swig 文件，setup.py:

from distutils.core import setup, Extension


auxchash_module = Extension('_auxchash',
                       sources=['auxchash_wrap.cxx', 'auxchash.cpp'],
                       )

setup (name = 'auxchash',
   version = '0.1',
   author      = "SWIG Docs",
   description = """Simple swig example from docs""",
   ext_modules = [auxchash_module],
   py_modules = ["auxchash"],
   )

而且都是用终端命令编译的：

swig -c++ -python auxchash.i
python setup.py build_ext --inplace

到目前为止一切顺利，编译没有错误。但是当我运行 a python main:

import auxchash
res,p,q,g,hk,tk = auxchash.keygen(10)

它给我以下错误：

File: "[...]/auxchash.py" import auxchash
File: "[...]/auxchash.py" auxchash=swig_import_helper()
File: "[...]/auxchash.py" return=importlib.import_module('_auxchash')
File: "[...]/__init.py__" __import__(name)`
ImportError: [...]/auxchash.so: undefined symbol: BN_bn2hex

我不知道怎么算。

Answer 1

您需要 link 您的模块针对 OpenSSL，e.g.something 如：

auxchash_module = Extension('_auxchash',
                       sources=['auxchash_wrap.cxx', 'auxchash.cpp'],
                       libraries=['crypto', 'ssl'],
                       )

（你可能只需要那个列表中的加密货币，我现在不能remember/tell）

swig c++ to python with openssl/bn.h

swig c++ to python with openssl/bn.h

c++

python

swig

openssl

bignum