C：分段故障与strcpy的

Question

我想知道，如果有人可以帮助我这个段错误，Valgrind的和gdb点到的strcpy（），但我仍然无法找到它..

void listusers(userstat* ptustat) 
{ 
    FILE* fileu = openfile("user_db"); 
    char* str = (char*) malloc(sizeof(char)*100); 
    char* temp = (char*) malloc(sizeof(char)*100); 
    int i = 0; 
    int offset = 0; 
    while (fgets(str,100,fileu) != NULL) 
     { 
      strcpy(temp,str); 
      strcpy((*(ptustat+i)).name,strtok(temp,"#")); 
      offset+=(strlen(temp)+1); 
      strcpy(temp,str+offset); 
      strcpy((*(ptustat+i)).contact,strtok(temp,"#")); 
      offset+=(strlen(temp)+1); 
      strcpy(temp,str+offset); 
      strcpy((*(ptustat+i)).uname,strtok(temp,"#")); 
      offset+=(strlen(temp)+1); 
      strcpy(temp,str+offset); 
      strtok(temp,"#"); 
      offset+=(strlen(temp)+1); 
      strcpy(temp,str+offset); 
      (*(ptustat+i)).saldo = atof(strtok(temp,"\n")); 
      i++; 
     } 
closefile(fileu); 
free(str);free(temp); 
} 

userstat definiton：

typedef struct userstat { 
char name[50]; 
char contact[50]; 
char uname[50]; 
float saldo; 
} userstat; 

而且它读取文件具有行是这样的： 名＃＃联系人＃用户名密码＃钱

GDB回溯：

Program received signal SIGSEGV, Segmentation fault. 
__strcpy_sse2_unaligned() at ../sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S:296 
296 ../sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S: Ficheiro ou directoria inexistente. 
(gdb) bt 
#0 __strcpy_sse2_unaligned() at ../sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S:296 
#1 0x00000000004030b2 in listusers() 
#2 0x0000000000401fee in statsmenu() 
#3 0x0000000000401c1d in menuinit() 
#4 0x0000000000400ecc in main() 
(gdb) 

呼叫该结构的功能和分配：

void statsmenu() 
    { 

     char x = '0'; 

     getchar(); 
     while (1) 
      { 
       prodstat db[100] = {{"",0.00,0.00,0.00}}; 
       prodstat *ptstat = db; 
       userstat dbu[100] = {{"","","",0.00}}; 
       userstat *ptustat = dbu; 
       listproducts(ptstat); 
       listusers(ptustat); 

Answer 1

我由当量（但可读）ptustat[i].xxx取代别扭(*ptustat + i)).xxx。

现在您对strtok的使用是错误和尴尬的。试试这个：

while (fgets(str, 100, fileu) != NULL) 
{ 
    strcpy(temp, str); 
    strcpy(ptustat[i].name, strtok(temp, "#")); 
    offset += (strlen(temp) + 1); 
    strcpy(temp, str + offset); 
    char *p = strtok(temp, "#"); 

    if (p == NULL) // p can be NULL here 
    { 
     printf("BUMMER\n"); 
     exit(1); 
    } 

    strcpy(ptustat[i].contact, p); 
    offset += (strlen(temp) + 1); 
    strcpy(temp, str + offset); 
    strcpy(ptustat[i].uname, strtok(temp, "#")); 
    offset += (strlen(temp) + 1); 
    strcpy(temp, str + offset); 
    strtok(temp, "#"); 
    offset += (strlen(temp) + 1); 
    strcpy(temp, str + offset); 
    ptustat[i].saldo = atof(strtok(temp, "\n")); 
    i++; 
} 

我离开的bug修正练习。

而且（不涉及您的问题）：

您可以通过

char str[100]; 

这通常是无意义的动态分配固定的空间缓冲区替换

char* str = (char*) malloc(sizeof(char)*100); 
... 
free(str); 

。