Question

我在Python中为OpenSLL libeay32.dll编写小包装器。对于大多数功能，可以按如下方式导入它们：

self.Function_Name = self._dll.Function_Name
self.Function_Name.restype = ctypes.c_int #for example
self.Function_Name.argtypes = [list of ctypes arguments]

不幸的是，我无法以任何方式导入任何宏：

X509_get_notAfter，X509_get_notBefore等。

任何想法，如何使用ctypes？

Answer 1

您无法导入宏。您导入的是DLL中的函数。宏不会从DLL导出，因此无需导入任何内容。

幸运的是，大多数宏都很简单，所以你可以在Python中重新实现它们。

或者，或者，在C中创建一个包装器DLL，为每个宏定义一个函数，编译并链接它，然后用ctypes导入包装器函数。

或者您可能希望使用Cython或其他技术代替ctypes。它们通常的工作方式是生成和编译包装C库并导出Python类型和函数的C代码，并且通常像导出C函数一样将C宏导出为Python函数。

或者，最简单的是...... PyOpenSSL已经包装了你需要的一切吗？

Answer 2

经过一番研究后，我决定回答我自己的问题。 X509_get_notAfter的宏看起来像这样：

#define X509_get_notAfter(x) ((x)->cert_info->validity->notAfter)

x - 是X509结构，它包含X509_CINF结构，其中包含X509_VAL结构，其中包含指向notAfter的指针：）

所以我的计划是在python代码中实现整个X509，X509_CINF和X509_VAL结构。

在C中它看起来像这样

struct x509_st
{
X509_CINF *cert_info;
X509_ALGOR *sig_alg;
ASN1_BIT_STRING *signature;
int valid;
int references;
char *name;
CRYPTO_EX_DATA ex_data;
/* These contain copies of various extension values */
long ex_pathlen;
long ex_pcpathlen;
unsigned long ex_flags;
unsigned long ex_kusage;
unsigned long ex_xkusage;
unsigned long ex_nscert;
ASN1_OCTET_STRING *skid;
AUTHORITY_KEYID *akid;
X509_POLICY_CACHE *policy_cache;
STACK_OF(DIST_POINT) *crldp;
STACK_OF(GENERAL_NAME) *altname;
NAME_CONSTRAINTS *nc;
#ifndef OPENSSL_NO_RFC3779
STACK_OF(IPAddressFamily) *rfc3779_addr;
struct ASIdentifiers_st *rfc3779_asid;
#endif
#ifndef OPENSSL_NO_SHA
unsigned char sha1_hash[SHA_DIGEST_LENGTH];
#endif
X509_CERT_AUX *aux;
} /* X509 */;

X509_CINF看起来像这样：

typedef struct x509_cinf_st
{
ASN1_INTEGER *version;      /* [ 0 ] default of v1 */
ASN1_INTEGER *serialNumber;
X509_ALGOR *signature;
X509_NAME *issuer;
X509_VAL *validity;
X509_NAME *subject;
X509_PUBKEY *key;
ASN1_BIT_STRING *issuerUID;     /* [ 1 ] optional in v2 */
ASN1_BIT_STRING *subjectUID;        /* [ 2 ] optional in v2 */
STACK_OF(X509_EXTENSION) *extensions;   /* [ 3 ] optional in v3 */
ASN1_ENCODING enc;
} X509_CINF;

这是X509_VAL：

typedef struct X509_val_st
{
ASN1_TIME *notBefore;
ASN1_TIME *notAfter;
} X509_VAL;

为了使整个任务更容易，我决定用ctypes.c_void_p替换所有我不想访问的结构的指针

所以我的python代码现在看起来像这样：

class X509_val_st(ctypes.Structure):

_fields_ = [('notBefore',       ctypes.c_void_p),
            ('notAfter',        ctypes.c_void_p)]


class X509_cinf_st(ctypes.Structure):

_fields_ = [('version',         ctypes.c_void_p),
            ('serialNumber',    ctypes.c_void_p),
            ('signature',       ctypes.c_void_p),
            ('issuer',          ctypes.c_void_p),
            ('validity',        X509_val_st),
            ('subject',         ctypes.c_void_p),
            ('key',             ctypes.c_void_p),
            ('issuerUID',       ctypes.c_void_p),
            ('subjectUID',      ctypes.c_void_p),
            ('extensions',      ctypes.c_void_p),
            ('enc',             ctypes.c_uint)]


class X509_st(ctypes.Structure):

_fields_ = [('cert_info',     X509_cinf_st),
            ('sig_alg',       ctypes.c_void_p),
            ('signature',     ctypes.c_void_p),
            ('valid',         ctypes.c_int),
            ('references',    ctypes.c_int),
            ('name',          ctypes.c_void_p),
            ('ex_data',       ctypes.c_int),
            ('ex_pathlen',    ctypes.c_long),
            ('ex_pcpathlen',  ctypes.c_long),
            ('ex_flags',      ctypes.c_ulong),
            ('ex_kusage',     ctypes.c_ulong),
            ('ex_xkusage',    ctypes.c_ulong),
            ('ex_nscert',     ctypes.c_ulong),
            ('skid',          ctypes.c_void_p),
            ('akid',          ctypes.c_void_p),
            ('policy_cache',  ctypes.c_void_p),
            ('crldp',         ctypes.c_void_p),
            ('altname',       ctypes.c_void_p),
            ('nc',            ctypes.c_void_p),
            ('rfc3779_addr',  ctypes.c_void_p),
            ('rfc3779_asid',  ctypes.c_void_p),
            ('sha1_hash',     ctypes.c_char),
            ('aux',           ctypes.c_void_p)]

最后一步：将结构分配给从函数X509_new（）接收的指针：

self.X509_new = self._lib.X509_new
self.X509_new.restype = ctypes.POINTER(X509_st)
self.X509_new.argtypes = []

因此，OpenSSL宏X509_get_notBefore的python函数将如下所示：

def X509_get_notBefore(self):
    return self.X509[0].cert_info.validity.notBefore

libeay32.dll的包装：如何导入宏？

2 个答案: