c - 反序列化错误

Question

这个问题已经有答案了:

Crash or "segmentation fault" when data is copied/scanned/read to an uninitialized pointer (5 个回答)

已关闭 5 年前。

我正在实现一个简单的序列化和反序列化程序，但在反序列化期间出现错误，如段错误(核心转储)。

我正在使用“|”作为分隔符，检索数据。我认为我在将数据放回成员变量时犯了一个错误。

下一步我将尝试通过套接字发送数据

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAX 100

typedef struct Frame
{
    char p[MAX];
    char q[MAX];
    char r[MAX];

}frame;

void serial(char [] , frame*);
void deserial(char [], frame*); 


int main ()
{
    char buffer [MAX];

    int  i = 0;

    frame* packet1;
    frame* packet2;

    char temp[sizeof(frame)]; 

    strcpy(packet1->p, "1234");
    strcpy(packet1->q, "qwerty");
    strcpy(packet1->r, "abcdef");
    serial( temp, packet1);


    deserial( temp, packet2);
    return 0 ;
}

void serial ( char temp[], frame * packet1)
{
    char* p = temp;
    int len ;
    int i=0;

    len = strlen (packet1->p);
    while ( i<len)
    {
        *p = packet1->p[i];
         p++;
         i++;
    }   
    strcat(p,"|");
    p++;
    i  = 0;
    len = strlen (packet1->q);
    while ( i<len)
    {
        *p = packet1->q[i];
         p++;
         i++;
    }
    strcat(p,"|");
    p++;    
    i  = 0;
    len = strlen (packet1->r);
    while ( i<len)
    {
        *p = packet1->r[i];
         p++;
         i++;
    }
    strcat(p,"|");
    return;  
}

void deserial ( char temp[], frame *packet2)
{
    char *str = temp;
    int i= 0 ;
    char delimit[]="|";
    printf("\n");
    while (*str!='|')
    {
        printf ("%c\n", *str);
        packet2->p[i] = *str;  //error here
        str++;
        i++;
    }           
}

Answer 1

您对此代码有疑问

frame* packet1;   // This is a pointer and it is uninitialized
frame* packet2;

char temp[sizeof(frame)]; 

strcpy(packet1->p, "1234");  // Use of uninitialized pointer

你想做吗

frame packet1;
frame packet2;

char temp[sizeof(frame)]; 

strcpy(packet1.p, "1234");
...
serial( temp, &packet1);

进一步 - 当你这样做时

strcat(p,"|");

p 指向一些未初始化的内存，因此它不是字符串，并且 strcat 将(可能)失败。相反，请执行以下操作:

*p = '|';