Question

我的连接处理程序线程有问题，线程似乎工作正常，但我收到此异常，直到它终止：

*** stack smashing detected ***: ./listener2 terminated
Aborted (core dumped)

这是我的主题：

void* SocketHandler(void* par) {
    struct thread_par* parameters=(struct thread_par*) par;
    int *csock = parameters->client_desc;
    MYSQL_RES *mysql_res;

    int buffer_len = 128;
    char client_message[buffer_len];
    int bytecount;
    memset(client_message, 0, buffer_len);
    if ((bytecount = read(*csock, client_message, buffer_len) == -1)) {
        fprintf(stderr, "Error receiving data\n");
        close(*csock);
        return 0;
    }
    printf("Received bytes %d\nReceived string \"%s\"\n", bytecount, client_message);
    char *sensor_alive = strtok(client_message, "&&");
    /*
     * the next operations will be done only for alive sensors
     */
    if (sensor_alive != NULL && strcmp(sensor_alive, "ALIVE") == 0) {
            puts("sensor Alive OK");
            //mysql_quwry returns
            //Zero for success. Nonzero if an error occurred.
            if (mysql_query(parameters->mysql_conn,
                    "--query--")) {
                fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn));
                mysql_free_result(mysql_res);
                return 0;
            }
            mysql_res = mysql_use_result(parameters->mysql_conn);
        }

    puts("Query executed");
    if (mysql_res->lengths > 0) {
        //we will do a second query , don't need anymore this
        mysql_free_result(mysql_res);

        /*
         * creation of a string containing the current time with the following format
         * YYYY-MM-dd hh-mm-ss
         */
        time_t t;
        struct tm* tm;
        char Date[11], Time[9];

        time(&t);
        tm = localtime(&t);

        char time_string[20];
        strftime(time_string, sizeof time_string, "%Y-%m-%d %H:%M:%S", tm);
        puts(time_string);

        /*
         * creation of the query
         * UPDATE sensors SET alive = 1, updated_at='YYYY-MM-dd hh-mm-ss' WHERE id_device='id';
         */
        char* query_part_1 = "--query--";
        char* query_part_2 = "--query--";
        char query[sizeof(query_part_1) + sizeof(query_part_2)+ sizeof(time_string)];
        strcpy(query, query_part_1);
        strcpy(query + strlen(query_part_1), time_string);
        strcpy(query + strlen(query_part_1) + strlen(time_string),
                query_part_2);

        //ALIVE UPDATE QUERY
        if (mysql_query(parameters->mysql_conn, query)) {
            fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn));
            mysql_free_result(mysql_res);
            return 0;
        }
        //mysql_free_result(mysql_res);
        puts("Alive value updated");

        //jump the part 1 of the message
        strtok(NULL, "&&");
        //jump the part 2 of the message
        strtok(NULL, "&&");
        //jump the part 3 of the message
        strtok(NULL, "&&");
        //jump the part 4 of the message
        strtok(NULL, "&&");

        char* query_begin = "--query--";
        char* status_vector = strtok(NULL, "&&"); //part 5
        strtok(NULL, "&&"); //part 6 don't needed
        char* local_time = strtok(NULL, "&&"); //part 7
        char* timer = strtok(NULL, "&&"); //part 8
        char* created_at = strtok(NULL, "&&"); //part 9

        int total_len = 150;

        char query2[total_len];
        snprintf(query2, sizeof(query2), "%s('%s','%s','%s','%s','%s');",
                query_begin, status_vector, local_time, timer, created_at,
                time_string);

        puts(query2);

        if (mysql_query(parameters->mysql_conn, query2)) {
            fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn));
            return 0;
        }
        //mysql_free_result(mysql_res);
        puts("Value updated");

    }


    /*
     * ending thread operations
     */
    //close(*csock);
    //free(csock);
    puts("exiting thread");
    //pthread_exit(0);
    return 0;
}

这是我的输出

Received bytes 0
Received string "ALIVE&&000000000035&&STATION NUM. 1&&40.1234234&&14.1234234&&0000000&&192.___&&00&&18:9:49&&2&&"
sensor Alive OK
Query executed
2014-10-16 18:08:10
Alive value updated
INSERT INTO -------;
Value updated
exiting thread
*** stack smashing detected ***: ./listener2 terminated
Aborted (core dumped)

我在C方面不太好，所以我不知道如何解决我的问题你能救我吗？

Answer 1

你有一个缓冲区溢出，这就是你得到＆＃34;堆栈粉碎检测到的原因＆＃34;信息。检查你的代码。但我查看了你的代码，并且无法找到任何超支，老实说：）

Answer 2

编译时使用-fno-stack-protector作为选项。这将导致出现不同的错误，主要是分段错误。正如其他答案所提到的，这显然是缓冲区溢出。您可以使用strace或gdb运行程序，以检测代码中问题的确切位置。例如strace ./a.out或gdb a.out

Answer 3

您的query变量太小：

char query[sizeof(query_part_1) + sizeof(query_part_2) + sizeof(time_string)];

您已声明它足够大，只能容纳query_part_1，query_part_2和time_string中的字符数。您忘记考虑字符串终止的NUL字节，因此第三个strcpy调用将写入query的末尾并破坏堆栈。

退出线程时检测到堆栈粉碎

3 个答案: