SMIME_read_PKCS7_ex
p7_in = SMIME_read_PKCS7_ex(in, &indata, &p7);
return SMIME_read_PKCS7_ex(bio, bcont, NULL);
PKCS7 *SMIME_read_PKCS7_ex(BIO *bio, BIO **bcont, PKCS7 **p7);