我有一个非常奇怪的问题。我的代码运行了一段时间，然后我在linux中关闭了我的终端并再次打开它来运行代码，但现在我得到了分段错误。无法解读究竟发生了什么...任何帮助都将不胜感激。
我的代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "unistd.h"
#include <syslog.h>
#include <math.h>
#define MAXPROFILES 2
float Pearson(int mySum, int recSum, int multSum);
int main(int argc, char *argv[])
{
int sockfd, newsockfd, portno, clilen;
struct sockaddr_in serv_addr, cli_addr;
unsigned char buf[1024];
/*int my_data2[10] = {1,3,9,10};
int my_data[10] = {0}; // = {1,2,3,4,5};
int myDataBinary[500] = {0};
int myDataBinary2[500] = {0};
int recData[500] = {0};*/
int index1=0;
// char* pointer = buf;
struct profile_t
{
unsigned char length;
unsigned char type;
unsigned char *data;
};
typedef struct profile_datagram_t
{
unsigned char *src;
unsigned char *dst;
unsigned char ver;
unsigned char n;
struct profile_t profiles[MAXPROFILES];
} header;
header outObj;
int j =0;
int i =0;
if (argc < 2) {
fprintf(stderr,"usage: %s port_number1",argv[0]);
exit(1);
}
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR DETECTED !!! Problem in opening socket");
bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(portno);
if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
error("ERROR DETECTED !!! There was a problem in binding");
listen(sockfd, 10);
clilen = sizeof(cli_addr);
printf("Server listening on port number %d...\n", serv_addr.sin_port);
while(1){
newsockfd = accept(sockfd,(struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0)
error("ERROR DETECTED !!! the connection request was not accepted");
int rc = read(newsockfd,buf,100);
if(rc < 0){
printf("error");
}
else {
printf("success %d",rc);
}
outObj.src = malloc(4);// ***Editor's comment: try gdb/valgrind next time + examine your memory allocating arguments***
outObj.dst = malloc(4);
// printf(pointer);
memcpy(outObj.src,buf+0,4);
memcpy(outObj.dst,buf+4,4);
memcpy(&outObj.ver,buf+8,1);
memcpy(&outObj.n,buf+9,1);
printf("\nSource IP = ");
for(int i=0;i<4;i++){
printf("%d ",outObj.src[i]);
}
printf("\nDestination IP = ");
for(int i=0;i<4;i++){
printf("%d ",outObj.dst[i]);
}
printf("\nVersion = %d",outObj.ver);
printf("\nNumber of messages = %d",outObj.n);
int k = 10;
for(i=0;i<outObj.n;i++){
memcpy(&outObj.profiles[i].length,buf+k,1);
memcpy(&outObj.profiles[i].type,buf+k+1,1);
outObj.profiles[i].data = malloc(outObj.profiles[i].length);
memcpy(outObj.profiles[i].data,buf+k+2,5);
k +=7;
}
for(int i=0;i<outObj.n;i++){
printf("\n------- Message %d --------",i+1);
printf("\nLength : %d",outObj.profiles[i].length);
printf("\nType : %d\n",outObj.profiles[i].type);
for(int j=0;j<5;j++){
printf(" Data[%d] : %d",j,outObj.profiles[i].data[j]);
}
}
/*
for(int i=0; i<sizeof(my_data)/sizeof(int);i++)
{
if(my_data[i] > 0){
index1 = my_data[i];
myDataBinary[index1] = 1;
printf("my data %d = %d\n",index1,myDataBinary[index1]);
}
}
for(int i=0; i<sizeof(my_data2)/sizeof(int);i++){
if(my_data2[i] > 0){
index1 = my_data2[i];
myDataBinary2[index1] = 1;
printf("my data %d = %d\n",index1,myDataBinary2[index1]);
}
}*/
float rho;
for(int i=0;i<outObj.n;i++){
printf("\n\n---------- Values for Data Profile %d ------------",i+1);
index1=0;
int sumRecievedData = 0;
int sumMyData = 0;
int sumMultpliedData = 0;
int my_data[10] = {0};// = {1,2,3,4,5};
int myDataBinary[500] = {0};
int recData[500] = {0};
if(i==0){
my_data[0] = 1;
my_data[1] = 3;
my_data[2] = 9;
my_data[3] = 10;
}
else if(i==1){
my_data[0] = 1;
my_data[1] = 2;
my_data[2] = 3;
my_data[3] = 4;
my_data[4] = 5;
}
for(int i=0; i<sizeof(my_data)/sizeof(int);i++){
if(my_data[i] > 0){
index1 = my_data[i];
myDataBinary[index1] = 1;
//printf("my data %d = %d\n",index1,myDataBinary[index1]);
}
}
for (int j=0; j<outObj.profiles[i].length;j++) {
if(outObj.profiles[i].data[j] > 0){
index1 = outObj.profiles[i].data[j];
recData[index1] = 1;
}
}
for(int i=0;i<500;i++){
sumRecievedData += recData[i];
sumMyData += myDataBinary[i];
sumMultpliedData += recData[i] * myDataBinary[i];
}
printf("\nrecSum = %d, \nmySum = %d, \nmultSum = %d\n",sumRecievedData,sumMyData,sumMultpliedData);
rho = Pearson(sumMyData,sumRecievedData,sumMultpliedData);
printf("\nPearson Coefficient for Data Profile %d= %f\n",i+1,rho);
}
}
return 0;
}
float Pearson(int mySum, int recSum, int multSum){
float Cov =0;
float sdMyData = 0;
float sdRecievedData =0;
float rho;
int n = 500;
Cov = (1.0/(n-1))*(multSum - (1.0/n)*mySum*recSum);
sdMyData = sqrt((1.0/(n-1))*(mySum - (1.0/n)*mySum*mySum));
sdRecievedData = sqrt((1.0/(n-1))*(recSum - (1.0/n)*recSum*recSum));
printf("\nCovariance = %f, \nVarianceMyData = %f, \nVarianceRecData = %f",Cov,sdMyData,sdRecievedData);
if (sdMyData == 0.0 || sdRecievedData == 0.0){
rho = 0.0;
}
else{
rho = Cov/(sdMyData*sdRecievedData);
}
return(rho);
}
答案 0 :(得分：3)
我真的不想发帖回答，但有些事情我想大肆宣传。
首先，请学习使用gdb。在编译gcc -o ex ex.c -g时，查看scene.Add -g选项背后的内容非常方便。调用gdb ./ex如果编译成功。然后在gdb命令界面中键入run [-all sorts of arguments and options you have initially set up in your program]，gdb将显示进程/线程调用以及您需要的所有内容。轻松愉快。
其次，在您的代码中，显然您以不正确的方式分配内存。这就是我们在手册页中所拥有的内容：
#include <stdlib.h>
void *malloc(size_t size);
void free(void *ptr);
void *realloc(void *ptr, size_t size);
void *calloc(size_t nmemb, size_t size);
请注意，在您的情况下，您必须像header_imgonnause = (header*)malloc(sizeof(header)*memoryiwannahave)一样执行此操作。
第三，可能是最后一个，就此代码中的分段错误而言，您是否已查看过accept() read()和write()？如果连接中存在损坏的管道， bash会提示你出错。如果使用gdb，你就会知道是不是这样。
总而言之，请使用gdb / valgrind。