我认为是因为NULL指针异常。我的嵌入式系统由STM32F4,FreeRTOS和LwIP组成。核心取自ST示例。这是简单的UDP服务器的线程代码。

#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include "lwip/sockets.h"
#include "./udpCLI.h"
//#include "Sledge.h" //for assert_amsg(), which print what and where fails before stop execution

static void udpCLI_thread(void *arg)
{
    int sockfd; // socket file descriptor
    const uint16_t serverport = UDP_PORT_NUMBER_CLI;
    struct sockaddr_in serveraddr = {0}, clientaddr = {0};
    socklen_t addrlen;// = sizeof(struct sockaddr_in);
    const uint16_t bufin_SIZE = 200, bufout_SIZE = 1024;
    char *bufin  = malloc(bufin_SIZE);  assert_amsg(bufin != NULL);  // stops execution with printing message "ASSERT FAILED "bufin != NULL" in file udp_cli.c:42" in stdout/stderr
    char *bufout = malloc(bufout_SIZE); assert_amsg(bufout != NULL);

    LWIP_UNUSED_ARG(arg);  //(void)arg;

    debugf2( "udpCLI_thread"NEWLINE );

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    assert_msg("udpCLI_thread: ERROR opening socket", sockfd>=0);

    /*
     * build the server's Internet address
     */
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
    serveraddr.sin_port = htons(serverport);

    /*
     * bind: associate the socket with a port
     */
    if( bind(sockfd, (struct sockaddr *) &serveraddr, sizeof(serveraddr)) < 0 )
        error("udpCLI_thread: ERROR on binding");

    // main loop: wait for a datagram, then echo it
    while(1)
    {
        addrlen = sizeof(struct sockaddr_in);  // THIS DID NOT HELP
        // recvfrom: receive a UDP datagram from a client
        int n = recvfrom(sockfd, bufin, bufin_SIZE, /*flags*/0, (struct sockaddr*)&clientaddr, &addrlen);
        // handle rusult
        //if (n < 0)
        // future process and response
        //....
}


如果输入消息的长度超过19个字节,则程序控制永远不会从recvfrom()函数返回。并且永远不会从文件sys_arch_mbox_fetch(&conn->recvmbox, &buf, 0);的行netconn_recv_data()中的函数api_lib.c中的函数371返回。
请帮助解决此问题。

最佳答案

那是我的错问题出在错误的内存分配和释放任务中。
我感谢所有同情者。

关于c - 如果输入字符串长于19个字节,则LwIP套接字上的UDP服务器会陷入硬故障,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/37598903/

10-11 18:42