我的项目有一个调用函数
void process_message(char *dev_ip, json_t *dev_config, char* message, json_t *extra_info, long col_ts, long log_counter, char *client_id, int unique_id)
{
......
char *encoded_msg;
//g_mutex_lock(&mutex_encode);
//encoded_msg = get_encoded_msg(message, charset);
//g_mutex_unlock(&mutex_encode);
encoded_msg = message;
if(encoded_msg == NULL)
{
return;
}
//note the function here////
GSList *parsed_msg = LineParser(dev_ip, encoded_msg, "\n", file_path, unique_id); //get list of parsed message
zlog_debug(c, "Number of parsed msg: %d", g_slist_length(parsed_msg));
GSList *iterator = NULL;
for (iterator = parsed_msg; iterator; iterator = iterator->next)
{
//memory read error if freed in another function///
zlog_debug(c, "Current item is '%s'\n", iterator->data);
char *encoded_single_msg = (char *)iterator->data;
}
}
我的功能LineParser为
GSList *LineParser(char* dev_ip, char *msg_full, char *separator, char *file_path, int unique_id)
{
GSList *parsed_msg = NULL;
char connection_id[50];
sprintf(connection_id,"%s|%d", dev_ip, unique_id);
char *msg_concat;
// inserting {file_path : last_not_complete_line} logic to TCP_CACHE
//and removing the correspoing last_line
g_mutex_lock (&mutex_hash_main);
// char *last_line = (char *) (g_hash_table_lookup((GHashTable *) g_hash_table_lookup(TCP_CACHE, connection_id), file_path));
GHashTable *t_filepath_msg_dict = NULL; //for {file_path : last_not_complete_line}
if (TCP_CACHE != NULL)
{
t_filepath_msg_dict = (GHashTable *)(g_hash_table_lookup(TCP_CACHE, connection_id));
if (t_filepath_msg_dict != NULL)
{
char *last_line = (char *) (g_hash_table_lookup(t_filepath_msg_dict, file_path));
if(last_line != NULL) //if the hash has device ip, append the value to msg
{
zlog_debug(c,"concatenating: str1: %s and str2: %s\n", last_line, msg_full);
////note the asprintf which is to be freed
asprintf(&msg_concat,"%s%s", last_line, msg_full);
g_hash_table_remove(t_filepath_msg_dict, file_path);
msg_full = msg_concat;
free(msg_concat);
}
}
}
int msg_len = strlen(msg_full);
char last_char = msg_full[msg_len - 1];
zlog_debug(c, "len of message: %d", msg_len);
zlog_debug(c, "last char is : %c", last_char);
char *token=NULL;
char *remaining_str=NULL;
token = strtok_r(msg_full, "\n", &remaining_str);
while(token != NULL)
{
if(token[0]==' ')
{
token = trimwhitespace_parser (token);
if(strcmp(token,"")==0)
{
//insert this token to GSList
parsed_msg = g_slist_prepend (parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
continue;
}
}
if(strcmp(remaining_str,"")==0)
{
if(strlen(token) > 10000)
{
zlog_warn(c, "Message too big(more than 10000 len). Stop looking for new line and process msg");
g_hash_table_remove(t_filepath_msg_dict, file_path);
}
else
{
if(last_char=='\n')
{
//new line is the last character. do nothing
zlog_debug(c, "last character is new line");
}
else
{
zlog_debug(c, "last character is not new line");
//new line not received
if (t_filepath_msg_dict == NULL) //insert new record
{
GHashTable *each_filepath_msg_dict = g_hash_table_new_full(g_str_hash, g_str_equal, key_str_destroy_cb_parser, value_str_destroy_cb_parser);
zlog_debug(c,"Inserting file_path: %s to connection_id: %s", file_path, connection_id);
g_hash_table_insert(each_filepath_msg_dict, strdup(file_path), strdup(token));
g_hash_table_insert(TCP_CACHE, strdup(connection_id), each_filepath_msg_dict);
}
else //update existing record
{
zlog_debug(c,"Connection_id :%s is already found; appending/replacing file_path :%s", connection_id, file_path);
g_hash_table_insert(t_filepath_msg_dict, strdup(file_path), strdup(token));
}
g_mutex_unlock(&mutex_hash_main);
return parsed_msg;
}
}
}
//insert token to GSList
parsed_msg = g_slist_prepend (parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
}
g_mutex_unlock(&mutex_hash_main);
return parsed_msg;
}
这里的代码我有asprint作为 asprintf（＆amp; msg_concat，＆＃34;％s％s＆＃34;，last_line，msg_full）;
需要释放这个msg_concat以减少内存泄漏。但是当我最后使用free（msg_concat）时。我无法正常释放内存，并在 process_message
给我错误内存读取错误**for (iterator = parsed_msg; iterator; iterator = iterator->next)
{
zlog_debug(c, "Current item is '%s'\n", iterator->data);
char *encoded_single_msg = (char *)iterator->data;
}**
如何在LineParser函数中正确释放msg_concat而不会在process_message函数中获取内存读取错误？
返回指针的列表是否指向与调用函数相同的msg_concat地址，因此无法在同一个LineParser函数中释放？
编辑： 我试图将列表作为参考传递，并将msg_concat作为：
返回GSList *parsed_msg=NULL;
char *msg_concat = LineParser(dev_ip, encoded_msg, "\n", file_path, unique_id,&parsed_msg); //get list of parsed message
zlog_debug(c, "Number of parsed msg: %d", g_slist_length(parsed_msg));
GSList *iterator = NULL;
for (iterator = parsed_msg; iterator; iterator = iterator->next)
{
zlog_debug(c, "Current item is '%s'\n", iterator->data);
char *encoded_single_msg = (char *)iterator->data;
json_object_set_new(extra_info, "client_id", json_string(client_id));
// json_object_set_new(extra_info, "parser", json_string(parser));
#ifdef DEBUG
char *extra_info_st;
extra_info_st = json_dumps(extra_info, JSON_INDENT(4));
zlog_debug(c,"extra_info_st msg is: %s\n", extra_info_st);
int num_of_fields_after = json_object_size(extra_info);
zlog_debug(c,"extra size is : %d\n", num_of_fields_after);
free(extra_info_st);
#endif
event = create_json_object(lp_name, extra_info, encoded_single_msg, dev_ip, dev_config, mid, col_ts, col_type, log_counter);
/* send message to upper layer */
send_event_with_mid(sender, event, normalizer, repo);
// AFREE(mid);
json_decref(event);
// AFREE(encoded_single_msg);
}
//json_decref(extra_info);
free(msg_concat);
g_slist_free(parsed_msg);
}
我写了LineParser以将msg_concat返回为：
char *LineParser(char* dev_ip, char *msg_full, char *separator, char *file_path, int unique_id, GSList **parsed_msg)
{
//GSList *parsed_msg = NULL;
char connection_id[50];
sprintf(connection_id,"%s|%d", dev_ip, unique_id);
char *msg_concat;
// inserting {file_path : last_not_complete_line} logic to TCP_CACHE
//and removing the correspoing last_line
g_mutex_lock (&mutex_hash_main);
// char *last_line = (char *) (g_hash_table_lookup((GHashTable *) g_hash_table_lookup(TCP_CACHE, connection_id), file_path));
GHashTable *t_filepath_msg_dict = NULL; //for {file_path : last_not_complete_line}
if (TCP_CACHE != NULL)
{
t_filepath_msg_dict = (GHashTable *)(g_hash_table_lookup(TCP_CACHE, connection_id));
if (t_filepath_msg_dict != NULL)
{
char *last_line = (char *) (g_hash_table_lookup(t_filepath_msg_dict, file_path));
if(last_line != NULL) //if the hash has device ip, append the value to msg
{
zlog_debug(c,"concatenating: str1: %s and str2: %s\n", last_line, msg_full);
asprintf(&msg_concat,"%s%s", last_line, msg_full);
g_hash_table_remove(t_filepath_msg_dict, file_path);
msg_full = msg_concat;
}
}
}
int msg_len = strlen(msg_full);
char last_char = msg_full[msg_len - 1];
zlog_debug(c, "len of message: %d", msg_len);
zlog_debug(c, "last char is : %c", last_char);
char *token=NULL;
char *remaining_str=NULL;
token = strtok_r(msg_full, "\n", &remaining_str);
while(token != NULL)
{
if(token[0]==' ')
{
token = trimwhitespace_parser (token);
if(strcmp(token,"")==0)
{
//insert this token to GSList
*parsed_msg = g_slist_prepend (*parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
continue;
}
}
if(strcmp(remaining_str,"")==0)
{
if(strlen(token) > 10000)
{
zlog_warn(c, "Message too big(more than 10000 len). Stop looking for new line and process msg");
g_hash_table_remove(t_filepath_msg_dict, file_path);
}
else
{
if(last_char=='\n')
{
//new line is the last character. do nothing
zlog_debug(c, "last character is new line");
}
else
{
zlog_debug(c, "last character is not new line");
//new line not received
if (t_filepath_msg_dict == NULL) //insert new record
{
GHashTable *each_filepath_msg_dict = g_hash_table_new_full(g_str_hash, g_str_equal, key_str_destroy_cb_parser, value_str_destroy_cb_parser);
zlog_debug(c,"Inserting file_path: %s to connection_id: %s", file_path, connection_id);
g_hash_table_insert(each_filepath_msg_dict, strdup(file_path), strdup(token));
g_hash_table_insert(TCP_CACHE, strdup(connection_id), each_filepath_msg_dict);
}
else //update existing record
{
zlog_debug(c,"Connection_id :%s is already found; appending/replacing file_path :%s", connection_id, file_path);
g_hash_table_insert(t_filepath_msg_dict, strdup(file_path), strdup(token));
}
g_mutex_unlock(&mutex_hash_main);
return msg_concat;
}
}
}
//insert token to GSList
*parsed_msg = g_slist_prepend (*parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
}
g_mutex_unlock(&mutex_hash_main);
return msg_concat;
}
然后在返回和释放列表后释放msg_concat会使valgrind无效;
答案 0 :(得分：1)
获取代码并进行最少的更改以处理特定的内存管理问题。您的代码中可能还有其他问题。我没有检查过。
GSList *LineParser(char* dev_ip, char *msg_full, char *separator, char *file_path, int unique_id)
{
GSList *parsed_msg = NULL;
char connection_id[50];
sprintf(connection_id,"%s|%d", dev_ip, unique_id);
char *msg_concat = NULL; //Initialize!!!
// inserting {file_path : last_not_complete_line} logic to TCP_CACHE
//and removing the correspoing last_line
g_mutex_lock (&mutex_hash_main);
// char *last_line = (char *) (g_hash_table_lookup((GHashTable *) g_hash_table_lookup(TCP_CACHE, connection_id), file_path));
GHashTable *t_filepath_msg_dict = NULL; //for {file_path : last_not_complete_line}
if (TCP_CACHE != NULL)
{
t_filepath_msg_dict = (GHashTable *)(g_hash_table_lookup(TCP_CACHE, connection_id));
if (t_filepath_msg_dict != NULL)
{
char *last_line = (char *) (g_hash_table_lookup(t_filepath_msg_dict, file_path));
if(last_line != NULL) //if the hash has device ip, append the value to msg
{
zlog_debug(c,"concatenating: str1: %s and str2: %s\n", last_line, msg_full);
////note the asprintf which is to be freed
asprintf(&msg_concat,"%s%s", last_line, msg_full);
g_hash_table_remove(t_filepath_msg_dict, file_path);
msg_full = msg_concat;
//free(msg_concat); //Not safe to free here!
}
}
}
int msg_len = strlen(msg_full);
char last_char = msg_full[msg_len - 1];
zlog_debug(c, "len of message: %d", msg_len);
zlog_debug(c, "last char is : %c", last_char);
char *token=NULL;
char *remaining_str=NULL;
token = strtok_r(msg_full, "\n", &remaining_str);
while(token != NULL)
{
if(token[0]==' ')
{
token = trimwhitespace_parser (token);
if(strcmp(token,"")==0)
{
//insert this token to GSList
parsed_msg = g_slist_prepend (parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
continue;
}
}
if(strcmp(remaining_str,"")==0)
{
if(strlen(token) > 10000)
{
zlog_warn(c, "Message too big(more than 10000 len). Stop looking for new line and process msg");
g_hash_table_remove(t_filepath_msg_dict, file_path);
}
else
{
if(last_char=='\n')
{
//new line is the last character. do nothing
zlog_debug(c, "last character is new line");
}
else
{
zlog_debug(c, "last character is not new line");
//new line not received
if (t_filepath_msg_dict == NULL) //insert new record
{
GHashTable *each_filepath_msg_dict = g_hash_table_new_full(g_str_hash, g_str_equal, key_str_destroy_cb_parser, value_str_destroy_cb_parser);
zlog_debug(c,"Inserting file_path: %s to connection_id: %s", file_path, connection_id);
g_hash_table_insert(each_filepath_msg_dict, strdup(file_path), strdup(token));
g_hash_table_insert(TCP_CACHE, strdup(connection_id), each_filepath_msg_dict);
}
else //update existing record
{
zlog_debug(c,"Connection_id :%s is already found; appending/replacing file_path :%s", connection_id, file_path);
g_hash_table_insert(t_filepath_msg_dict, strdup(file_path), strdup(token));
}
g_mutex_unlock(&mutex_hash_main);
//If memory has been allocated then free it before returning.
if(msg_concat)
free(msg_concat);
return parsed_msg;
}
}
}
//insert token to GSList
parsed_msg = g_slist_prepend (parsed_msg, token);
token = strtok_r(NULL, "\n", &remaining_str);
}
g_mutex_unlock(&mutex_hash_main);
//Same here. If memory has been allocated then free it before returning.
if(msg_concat)
free(msg_concat);
return parsed_msg;
}
您可能遇到的另一个问题是“token”指向的内存是msg_concat指向的字符串的子集。如果要将这些添加到将超出LineParser函数生命周期的列表或哈希表中，那么您应该分配新数组并将“token”复制到新的char数组中。当列表或哈希表超出范围时，您还应该处理释放已分配的数组。
编辑......
您有两种选择。其中一项涉及对LineParser功能进行重大重组，以解决已经讨论过的问题。您还必须处理复杂的因素。例如，我没有可见性的“trimwhitespace_parser”函数必须通过移动数组的内容来删除任何前导空格，以便第一个非空白字符位于数组的第一个位置。这是因为你以后想要释放这个内存，如果从原始分配的内存中返回一个偏移量，那么你就麻烦了。每次调用strtok_r并获得非NULL响应时，您都必须分配一个足够大的char数组，然后将其复制到strtok_r返回的字符串中。您可以像在代码中一样使用asprintf函数来执行此操作。然后，您将使用已分配的数组而不是令牌。正如我已经提到的那样，你的处理过程中没有任何一个会导致你丢失/覆盖原始指针值，而原始指针值与原始指针偏移。如果发生这种情况，您将无法在以后释放它。此外，您的调用函数需要承担释放返回列表中所有项目的责任。
第二种选择相当简单，但无论如何都不优雅。如果涉及修改LineParser函数的原型以获取额外的char **参数。我们的想法是你将msg_concat分配给它，以便它“返回”到调用函数。然后，调用函数承担释放它的责任。因此，您的调用函数将声明char * ptr = NULL，然后在调用LineParser时将其作为＆amp; ptr传递。从LineParser返回时，只有在完成链接列表的所有使用等之后，您才可以免费（ptr）进行清理。