有几天我一直试图将我的服务器作为持续运行的守护进程运行。现在，我的服务器关闭与客户端的连接，然后自行关闭。所以我能够将我的数据包一次发送到服务器，但是当我尝试再次发送它时，我得到了一个分段错误错误。
此外，即使我编写了守护程序进程，我也不确定它的行为以及它是否正常工作。
服务器代码：
#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 myDataBinary[500] = {0};
int myDataBinary2[500] = {0};
int recData[500] = {0};*/
int index1=0;
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;
extern int daemon_proc; /* defined in error.c */
void daemon_init (const char *pname, int facility)
{
/* Our process ID and Session ID */
pid_t pid, sid;
/* Fork off the parent process */
pid = fork();
if (pid < 0) {
exit(EXIT_FAILURE);
}
/* If we got a good PID, then
we can exit the parent process. */
if (pid > 0) {
exit(EXIT_SUCCESS);
}
/* Change the file mode mask */
umask(0);
/* Open any logs here */
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
/* Log the failure */
exit(EXIT_FAILURE);
}
/* Change the current working directory */
if ((chdir("/")) < 0) {
/* Log the failure */
exit(EXIT_FAILURE);
}
/* Close out the standard file descriptors */
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
/* Daemon-specific initialization goes here */
}
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);
while (1){
printf("Server listening on port number %d...\n", serv_addr.sin_port);
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);
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]);
}
}
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;
//printf("rec data %d = %d\n",index1,recData[index1]);
}
}
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;
}
//exit(EXIT_SUCCESS);
}
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：1)
服务器在所谓的无限循环的底部执行return(0);，从而退出main()并终止。
如评论中所述，您的代码包含一个永远不会被调用的嵌套函数daemon_init()。嵌套函数是仅限GCC的功能;你应该避免使用它们。如果您确实调用它，服务器将会出现问题，因为它会关闭stdout和stderr，但您的代码会尝试写入已关闭的文件。
如果没有客户端代码，通过网络发送什么信息还远远不够清楚。有一个read()电话：
int rc = read(newsockfd,buf,100);
应该使用sizeof(buf)代替100;当你只使用100个字节时，使用char buf[1024];是浪费的。你检查你有一些数据;你没有检查你是否得到了你期望的所有数据。因此，您可能正在阅读未初始化的数据。
代码中还有许多其他类似的问题，特别是使用的常量有些不合适。正如评论中所指出的，代码没有正确模块化。
代码似乎没有响应客户端;其输出仅转到其标准输出（或错误）。
此代码编译得相当干净，但由于前面提到的原因，仍然不会调用daemon_init()。
#include <errno.h>
#include <math.h>
#include <netinet/in.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h> /* exit() */
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h> /* umask() */
#include <syslog.h>
#include <unistd.h>
#define MAXPROFILES 2
static void error(const char *fmt, ...)
{
va_list args;
int errnum = errno;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
fprintf(stderr, ": %d %s\n", errnum, strerror(errnum));
exit(1);
}
static float Pearson(int mySum, int recSum, int multSum);
static void daemon_init(void)
{
/* Our process ID and Session ID */
pid_t pid, sid;
/* Fork off the parent process */
pid = fork();
if (pid < 0)
error("failed to fork");
/* If we got a good PID, then
we can exit the parent process. */
if (pid > 0)
exit(EXIT_SUCCESS);
/* Change the file mode mask */
umask(0);
/* Open any logs here */
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0)
error("failed to set session ID");
/* Change the current working directory */
if ((chdir("/")) < 0)
error("failed to chdir to root");
/* Close out the standard file descriptors */
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
/* Daemon-specific initialization goes here */
}
int main(int argc, char *argv[])
{
int sockfd, newsockfd, portno;
socklen_t clilen;
struct sockaddr_in serv_addr, cli_addr;
unsigned char buf[1024];
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;
if (argc != 2)
error("usage: %s port", argv[0]);
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);
while (1)
{
clilen = sizeof(cli_addr);
printf("Server listening on port number %d...\n", serv_addr.sin_port);
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)
error("read error");
else
printf("read: success %d", rc);
outObj.src = malloc(4);
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 (int 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<outObj.n;i++)
{
printf("\n\n---------- Values for Data Profile %d ------------",i+1);
int index1=0;
int sumReceivedData = 0;
int sumMyData = 0;
int sumMultpliedData = 0;
int my_data[10] = {0};
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;
//printf("rec data %d = %d\n",index1,recData[index1]);
}
}
for (int i=0;i<500;i++)
{
sumReceivedData += recData[i];
sumMyData += myDataBinary[i];
sumMultpliedData += recData[i] * myDataBinary[i];
}
printf("\nrecSum = %d, \nmySum = %d, \nmultSum = %d\n",sumReceivedData,sumMyData,sumMultpliedData);
float rho = Pearson(sumMyData,sumReceivedData,sumMultpliedData);
printf("\nPearson Coefficient for Data Profile %d= %f\n",i+1,rho);
}
return 0;
}
//exit(EXIT_SUCCESS);
}
static float Pearson(int mySum, int recSum, int multSum)
{
float Cov =0;
float sdMyData = 0;
float sdReceivedData =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));
sdReceivedData = sqrt((1.0/(n-1))*(recSum - (1.0/n)*recSum*recSum));
printf("Covariance = %f\n",Cov);
printf("VarianceMyData = %f\n",sdMyData);
printf("VarianceRecData = %f\n",sdReceivedData);
if (sdMyData == 0.0 || sdReceivedData == 0.0)
rho = 0.0;
else
rho = Cov/(sdMyData*sdReceivedData);
return(rho);
}
它仍然需要做很多工作。