Ignore the function name in OpenSSL errors

The use of the function name in errors has been abandoned in OpenSSL 3.
Profit to replace the use of sprintf with snprintf.

src/socklib/Server.cpp

@@ -719,7 +719,8 @@ void GSISocketServer::SetErrorOpenSSL(const std::string &err)
 
   while( ERR_peek_error() ){
 
-    char error_msg_buf[512];
+    std::size_t const error_msg_buf_size = 512;
+    char error_msg_buf[error_msg_buf_size];
 
     const char *filename;
     int lineno;
@@ -729,7 +730,6 @@ void GSISocketServer::SetErrorOpenSSL(const std::string &err)
     long error_code = ERR_get_error_line_data(&filename, &lineno, &data, &flags);
 
     const char *lib = ERR_lib_error_string(error_code);
-    const char *func = ERR_func_error_string(error_code);
     const char *error_reason = ERR_reason_error_string(error_code);
 
     if (lib == NULL) {
@@ -741,11 +741,11 @@ void GSISocketServer::SetErrorOpenSSL(const std::string &err)
       }
     }
 
-    sprintf(error_msg_buf,
-        "%s %s [err:%lu,lib:%s,func:%s(file: %s+%d)]",
+    snprintf(error_msg_buf, error_msg_buf_size,
+        "%s %s [err:%lu,lib:%s,file:%s+%d]",
         (error_reason) ? error_reason : "",
-        (data) ? data : "",
-        error_code,lib,func,filename,lineno);
+        (data && (flags & ERR_TXT_STRING)) ? data : "",
+        error_code,lib,filename,lineno);
 
     openssl_errors.push_back(error_msg_buf);
   }