C套接字写入次数太多
在用户输入数据之后，它会写出在数据刚刚输入之前输入的一部分数据，如果这有意义的话？我只包含了一个片段，但有人知道为什么它会多次回复吗C套接字写入次数太多,c,sockets,read-write,C,Sockets,Read Write,在用户输入数据之后，它会写出在数据刚刚输入之前输入的一部分数据，如果这有意义的话？我只包含了一个片段，但有人知道为什么它会多次回复吗 #include<stdio.h> #include<string.h> #include<stdlib.h> #include<sys/socket.h> #include<arpa/inet.h> //inet_addr #include<unistd.h> // write #incl
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> // write
#include<pthread.h> // For Threading
#include<wiringPi.h>
void *connection_handler(void *);
void lightLED(int pin,int status);
int maxConnections = 1;
int totalConnections = 0;
int main(int argc , char *argv[])
{
int socket_desc , new_socket , c, *new_sock;
struct sockaddr_in server , client;
char *message;
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("bind failed");
}
puts("bind done");
//Listen
listen(socket_desc , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while( (new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
{
if(new_socket > 0)
{
if(totalConnections < maxConnections){
totalConnections++;
}
else
{
message = "Sorry Maximum Users Reached\n";
write(new_socket,message,strlen(message));
puts("Too many Users");
close(new_socket);
continue;
}
}
puts("Connection Accepted");
char *client_ip = inet_ntoa(client.sin_addr);
int client_port = ntohs(client.sin_port);
printf("ClientIP:%s\n",client_ip);
message = "Hello you have been accepted!\n";
write(new_socket, message , strlen(message));
pthread_t sniffer_thread;
new_sock = malloc(1);
*new_sock = new_socket;
if(pthread_create( &sniffer_thread, NULL , connection_handler , (void*) new_sock) <0)
{
perror("Could not create thread");
return 1;
}
puts("Handler Assigned");
}
if (new_socket<0)
{
perror("accept failed");
return 1;
}
return 0;
}
void *connection_handler(void *socket_desc)
{
int sock = *(int*)socket_desc;
int read_size;
char *message , client_message[2000];
message = "Greeting! I am your Connection Handler\n";
write(sock , message,strlen(message));
message = "What do you want to do\n";
write(sock,message,strlen(message));
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0)
{
write(sock , client_message , strlen(client_message));
printf("User Entered:%s\n",client_message);
int pin = client_message[0]-'0';
int status = client_message[1]-'0';
lightLED(pin,status);
}
if(read_size == 0)
{
puts("Client Disconnected\n");
fflush(stdout);
totalConnections--;
}else if(read_size == -1)
{
perror("recv Failed");
}
free(socket_desc);
return 0;
}
void lightLED(int pin,int status)
{
char message;
if(wiringPiSetup() == -1){
puts("wiringPi Error");
exit(1);
}
//pinMode(pin,OUTPUT);
printf("Changing LED Pin- %d Status- %d\n",pin,status);
//digitalWrite(pin,status);
}
#包括
#包括
#包括
#包括
#包括//inet\u addr
#包括//写入
#包括//用于线程
#包括
void*连接处理程序（void*）；
无效发光二极管（内部引脚，内部状态）；
int-maxConnections=1；
int totalConnections=0；
int main（int argc，char*argv[]）
{
int插座描述，新插座，c，*新插座；
服务器、客户端中的结构sockaddr_；
字符*消息；
//创建套接字
socket\u desc=socket（AF\u INET，SOCK\u STREAM，0）；
如果（套接字描述==-1）
{
printf（“无法创建套接字”）；
}
//在结构中准备sockaddr_
server.sinu family=AF\u INET；
server.sin\u addr.s\u addr=INADDR\u ANY；
server.sin_port=htons（8888）；
//束缚
if（绑定（socket_desc，（struct sockaddr*）&server，sizeof（server））<0
{
看跌期权（“绑定失败”）；
}
看跌期权（“绑定完成”）；
//听
听（插座描述，3）；
//接受和传入连接
puts（“等待传入连接…”）；
c=sizeof（结构sockaddr_in）；
而（（新套接字=接受（套接字描述，（结构sockaddr*）和客户端，（socklen\u t*）和c）））
{
如果（新插槽>0）
{
if（总连接数<最大连接数）{
totalConnections++；
}
其他的
{
message=“对不起，已达到最大用户数\n”；
写入（新的_套接字、消息、strlen（消息））；
puts（“太多用户”）；
关闭（新的_插座）；
继续；
}
}
看跌期权（“已接受连接”）；
char*client\u ip=inet\u ntoa（client.sin\u addr）；
int client_port=ntohs（client.sin_port）；
printf（“客户端：%s\n”，客户端\u ip）；
message=“您好，您已被接受！\n”；
写入（新的_套接字、消息、strlen（消息））；
pthread\u t sniffer\u线程；
新_sock=malloc（1）；
*新_插座=新_插座；
if（pthread_create（&sniffer_thread，NULL，connection_handler，（void*）new_sock）第一次通过
我不确定您看到的是什么问题。我已经将您的代码（状态非常好-做得很好；我已经查看了很多代码，其中有许多更糟糕的问题）编译并运行，它似乎对我有效：
$ nc localhost 8888
Connection Accepted
ClientIP:127.0.0.1
Handler Assigned
Hello you have been accepted!
Greeting! I am your Connection Handler
What do you want to do
01
User Entered:01
Changing LED Pin- 0 Status- 1
01
21
User Entered:21
Changing LED Pin- 2 Status- 1
21
31
User Entered:31
Changing LED Pin- 3 Status- 1
31
we wish you a merry Christmas
User Entered:we wish you a merry Christmas
Changing LED Pin- 71 Status- 53
we wish you a merry Christmas
Client Disconnected
$
运行时的代码是：
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
//#include <wiringPi.h>
void *connection_handler(void *);
void lightLED(int pin, int status);
int maxConnections = 1;
int totalConnections = 0;
int main(void)
{
int socket_desc, new_socket, c, *new_sock;
struct sockaddr_in server, client;
char *message;
socket_desc = socket(AF_INET, SOCK_STREAM, 0);
if (socket_desc == -1)
{
printf("Could not create socket");
return 1;
}
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if ( bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
{
puts("bind failed");
return 1;
}
puts("bind done");
if (listen(socket_desc, 3) != 0)
{
perror("listen() failed");
return 1;
}
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while ((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)))
{
if (new_socket > 0)
{
if (totalConnections < maxConnections)
totalConnections++;
else
{
message = "Sorry Maximum Users Reached\n";
write(new_socket, message, strlen(message));
puts("Too many Users");
close(new_socket);
continue;
}
}
puts("Connection Accepted");
char *client_ip = inet_ntoa(client.sin_addr);
//int client_port = ntohs(client.sin_port);
printf("ClientIP:%s\n", client_ip);
message = "Hello you have been accepted!\n";
write(new_socket, message, strlen(message));
pthread_t sniffer_thread;
new_sock = malloc(1 * sizeof(int)); // Oops!
if (new_sock == 0) { perror("out of memory"); return 1; }
*new_sock = new_socket;
if (pthread_create( &sniffer_thread, NULL, connection_handler, (void*) new_sock) <0)
{
perror("Could not create thread");
return 1;
}
puts("Handler Assigned");
}
if (new_socket<0)
{
perror("accept failed");
return 1;
}
return 0;
}
void *connection_handler(void *socket_desc)
{
int sock = *(int*)socket_desc;
int read_size;
char *message, client_message[2000];
message = "Greeting! I am your Connection Handler\n";
write(sock, message, strlen(message));
message = "What do you want to do\n";
write(sock, message, strlen(message));
while ((read_size = recv(sock, client_message, 2000, 0)) > 0)
{
write(sock, client_message, strlen(client_message));
printf("User Entered:%s\n", client_message);
int pin = client_message[0]-'0';
int status = client_message[1]-'0';
lightLED(pin, status);
}
if (read_size == 0)
{
puts("Client Disconnected\n");
fflush(stdout);
totalConnections--;
}
else if (read_size == -1)
{
perror("recv Failed");
}
free(socket_desc);
return 0;
}
void lightLED(int pin, int status)
{
// if (wiringPiSetup() == -1)
// {
// puts("wiringPi Error");
// exit(1);
// }
printf("Changing LED Pin- %d Status- %d\n", pin, status);
}
第二关
另一个测试运行-显示非空终止输入的问题：
$ nc localhost 8888
Connection Accepted
ClientIP:127.0.0.1
Hello you have been accepted!
Handler Assigned
Greeting! I am your Connection Handler
What do you want to do
this is a long string - what will you do with it?
User Entered:this is a long string - what will you do with it?
Changing LED Pin- 68 Status- 56
this is a long string - what will you do with it?
01
User Entered:01
s is a long string - what will you do with it?
Changing LED Pin- 0 Status- 1
01
s is a long string - what will you do with it?
Client Disconnected
$
当我用telnet
而不是nc
运行它时，我得到了您看到的错误行为，我想：
$ telnet localhost 8888
Trying 127.0.0.1...
Connection Accepted
ClientIP:127.0.0.1
Handler Assigned
Connected to localhost.
Escape character is '^]'.
Hello you have been accepted!
Greeting! I am your Connection Handler
What do you want to do
Would you like a biscuit?
User Entered:Would you like a biscuit?
Changing LED Pin- 39 Status- 63
Would you like a biscuit?
93
User Entered:93
d you like a biscuit?
Changing LED Pin- 9 Status- 3
93
d you like a biscuit?
Intriguing
User Entered:Intriguing
ke a biscuit?
Changing LED Pin- 25 Status- 62
Intriguing
ke a biscuit?
Bye
User Entered:Bye
guing
ke a biscuit?
Changing LED Pin- 18 Status- 73
Bye
guing
ke a biscuit?
User Entered:ye
guing
ke a biscuit?
Changing LED Pin- -44 Status- 73
ye
guing
ke a biscuit?
^CUser Entered:????guing
ke a biscuit?
Changing LED Pin- -49 Status- -60
User Entered:???guing
ke a biscuit?
Changing LED Pin- -49 Status- -53
?guing
ke a biscuit?
User Entered:??guing
ke a biscuit?
...continued attempts with control-C (interrupt)...
...and control-D (EOF) not producing anything useful...
^]
telnet> qConnection closed.
Client Disconnected
$
因此，telnet
可能误导了您……您的服务器没有任何问题，只是客户端（telnet
）没有按照您的预期运行
更新代码
与更新的服务器代码的对话：
$ nc localhost 8888
Connection Accepted
ClientIP: 127.0.0.1
Handler Assigned
Hello you have been accepted!
Greetings! I am your Connection Handler
What do you want to do
13
User Entered:13
Changing LED Pin 1 status 3
13
21
User Entered:21
Changing LED Pin 2 status 1
21
elephants?
User Entered:elephants?
Changing LED Pin 53 status 60
elephants?
21
User Entered:21
Changing LED Pin 2 status 1
21
quit
User Entered:quit
Changing LED Pin 65 status 69
quit
Client Disconnected
$
更新的服务器代码
这个版本关注长度并确保字符串以null结尾
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
//#include <wiringPi.h>
void *connection_handler(void *);
void lightLED(int pin, int status);
static void write_sock(int sock, const char *msg);
int maxConnections = 1;
int totalConnections = 0;
int main(void)
{
int socket_desc, new_socket, c, *new_sock;
struct sockaddr_in server, client;
socket_desc = socket(AF_INET, SOCK_STREAM, 0);
if (socket_desc == -1)
{
printf("Could not create socket");
return 1;
}
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
{
puts("bind failed");
return 1;
}
puts("bind done");
if (listen(socket_desc, 3) != 0)
{
perror("listen() failed");
return 1;
}
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while ((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)))
{
if (new_socket > 0)
{
if (totalConnections < maxConnections)
totalConnections++;
else
{
write_sock(new_socket, "Sorry Maximum Users Reached\n");
puts("Too many Users");
close(new_socket);
continue;
}
}
puts("Connection Accepted");
char *client_ip = inet_ntoa(client.sin_addr);
//int client_port = ntohs(client.sin_port);
printf("ClientIP: %s\n", client_ip);
write_sock(new_socket, "Hello you have been accepted!\n");
pthread_t sniffer_thread;
new_sock = malloc(1 * sizeof(int)); // Oops!
if (new_sock == 0) { perror("out of memory"); return 1; }
*new_sock = new_socket;
if (pthread_create(&sniffer_thread, NULL, connection_handler, (void *)new_sock) < 0)
{
perror("Could not create thread");
return 1;
}
puts("Handler Assigned");
}
if (new_socket < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
// Avoid repetition - use functions!
static void write_sock(int sock, const char *msg)
{
int len = strlen(msg);
if (write(sock, msg, len) != len)
{
perror("short write on socket");
exit(1);
}
}
void *connection_handler(void *socket_desc)
{
int sock = *(int*)socket_desc;
int read_size;
char client_message[2000];
write_sock(sock, "Greetings! I am your Connection Handler\n");
write_sock(sock, "What do you want to do\n");
while ((read_size = recv(sock, client_message, 2000, 0)) > 0)
{
client_message[read_size] = '\0';
write_sock(sock, client_message);
printf("User Entered:%s\n", client_message);
int pin = client_message[0]-'0';
int status = client_message[1]-'0';
lightLED(pin, status);
}
if (read_size == 0)
{
puts("Client Disconnected\n");
fflush(stdout);
totalConnections--;
}
else if (read_size == -1)
{
perror("recv Failed");
}
free(socket_desc);
return 0;
}
void lightLED(int pin, int status)
{
// if (wiringPiSetup() == -1)
// {
// puts("wiringPi Error");
// exit(1);
// }
printf("Changing LED Pin %d status %d\n", pin, status);
}
您没有检查任何write（）
调用是否成功；这可能是一个问题。您会被告知刚刚从套接字读取的消息大小；然后使用strlen（）写回消息
来确定大小。但是，您的写入操作不包含空终止符，因此没有理由期望读取的数据包含空终止符，因此您可能会写入各种垃圾。printf（）
也可能在打印垃圾。回显客户端发送的、未更改的、未验证的内容有点奇怪。您不应该等到选中lightLED（）后再响应吗
？啊，好的。是的，原因是这样的，因为我把它作为一个测试，回复发送给它的内容只是为了测试它的效果。你建议如何使用收到的信息？'lightLED（）'需要2个整数，正如你所见。lightLED（）
返回一个状态，指示它是否能够执行请求？LED数字是否有效？请求是否有效？回显接收到的数据是否良好；正确回显更好。日志文件（或标准输出，如printf（）
）是一个记录细节的好地方。如果协议允许，回传给客户是可以的-你确实意识到你在设计协议，不是吗？设计自己的协议的一个优点是你可以让它按你想要的方式工作。你最多可以接受2000个字符；你只使用2个字符。这是一个很大的差异。是的，我意识到ed我正在着手制定一种协议……我从一个基本版本开始，没有改变字符数量等。当我尝试将Pin和状态发送到lightLED时，效果很好……但是当我断开连接时，它会向它发送两次信息，这就是为什么我关注这个问题。这是我的“主要功能”吗POSIX pthread？接口看起来可能是。你确定只有一个线程使用给定的套接字吗？如果多个线程使用同一个套接字，可能会有问题。谢谢你，先生。我会试试。我一直在Telnet中使用它，当我在nc中尝试它时，效果很好。你喜欢在Telnet中尝试吗？你可能会看到这一点当您关闭连接客户端时，服务器会收到另外两条消息，编号为-44-44 is^D-'0'
；telnet
正在发送未经解释的控件-D。啊，好的，现在是生命之源..telnet。感谢您的帮助
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
//#include <wiringPi.h>
void *connection_handler(void *);
void lightLED(int pin, int status);
static void write_sock(int sock, const char *msg);
int maxConnections = 1;
int totalConnections = 0;
int main(void)
{
int socket_desc, new_socket, c, *new_sock;
struct sockaddr_in server, client;
socket_desc = socket(AF_INET, SOCK_STREAM, 0);
if (socket_desc == -1)
{
printf("Could not create socket");
return 1;
}
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
{
puts("bind failed");
return 1;
}
puts("bind done");
if (listen(socket_desc, 3) != 0)
{
perror("listen() failed");
return 1;
}
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while ((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)))
{
if (new_socket > 0)
{
if (totalConnections < maxConnections)
totalConnections++;
else
{
write_sock(new_socket, "Sorry Maximum Users Reached\n");
puts("Too many Users");
close(new_socket);
continue;
}
}
puts("Connection Accepted");
char *client_ip = inet_ntoa(client.sin_addr);
//int client_port = ntohs(client.sin_port);
printf("ClientIP: %s\n", client_ip);
write_sock(new_socket, "Hello you have been accepted!\n");
pthread_t sniffer_thread;
new_sock = malloc(1 * sizeof(int)); // Oops!
if (new_sock == 0) { perror("out of memory"); return 1; }
*new_sock = new_socket;
if (pthread_create(&sniffer_thread, NULL, connection_handler, (void *)new_sock) < 0)
{
perror("Could not create thread");
return 1;
}
puts("Handler Assigned");
}
if (new_socket < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
// Avoid repetition - use functions!
static void write_sock(int sock, const char *msg)
{
int len = strlen(msg);
if (write(sock, msg, len) != len)
{
perror("short write on socket");
exit(1);
}
}
void *connection_handler(void *socket_desc)
{
int sock = *(int*)socket_desc;
int read_size;
char client_message[2000];
write_sock(sock, "Greetings! I am your Connection Handler\n");
write_sock(sock, "What do you want to do\n");
while ((read_size = recv(sock, client_message, 2000, 0)) > 0)
{
client_message[read_size] = '\0';
write_sock(sock, client_message);
printf("User Entered:%s\n", client_message);
int pin = client_message[0]-'0';
int status = client_message[1]-'0';
lightLED(pin, status);
}
if (read_size == 0)
{
puts("Client Disconnected\n");
fflush(stdout);
totalConnections--;
}
else if (read_size == -1)
{
perror("recv Failed");
}
free(socket_desc);
return 0;
}
void lightLED(int pin, int status)
{
// if (wiringPiSetup() == -1)
// {
// puts("wiringPi Error");
// exit(1);
// }
printf("Changing LED Pin %d status %d\n", pin, status);
}
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
//#include <wiringPi.h>
void *connection_handler(void *);
void lightLED(int pin, int status);
static void write_sock(int sock, const char *msg);
int maxConnections = 1;
int totalConnections = 0;
int main(void)
{
int socket_desc, new_socket, c, *new_sock;
struct sockaddr_in server, client;
socket_desc = socket(AF_INET, SOCK_STREAM, 0);
if (socket_desc == -1)
{
printf("Could not create socket");
return 1;
}
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
{
puts("bind failed");
return 1;
}
puts("bind done");
if (listen(socket_desc, 3) != 0)
{
perror("listen() failed");
return 1;
}
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while ((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)))
{
if (new_socket > 0)
{
if (totalConnections < maxConnections)
totalConnections++;
else
{
write_sock(new_socket, "Sorry Maximum Users Reached\n");
puts("Too many Users");
close(new_socket);
continue;
}
}
puts("Connection Accepted");
char *client_ip = inet_ntoa(client.sin_addr);
//int client_port = ntohs(client.sin_port);
printf("ClientIP: %s\n", client_ip);
write_sock(new_socket, "Hello you have been accepted!\n");
pthread_t sniffer_thread;
new_sock = malloc(1 * sizeof(int)); // Oops!
if (new_sock == 0) { perror("out of memory"); return 1; }
*new_sock = new_socket;
if (pthread_create(&sniffer_thread, NULL, connection_handler, (void *)new_sock) < 0)
{
perror("Could not create thread");
return 1;
}
puts("Handler Assigned");
}
if (new_socket < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
// Avoid repetition - use functions!
static void write_sock(int sock, const char *msg)
{
int len = strlen(msg);
if (write(sock, msg, len) != len)
{
perror("short write on socket");
exit(1);
}
}
void *connection_handler(void *socket_desc)
{
int sock = *(int*)socket_desc;
int read_size;
char client_message[2000];
write_sock(sock, "Greetings! I am your Connection Handler\n");
write_sock(sock, "What do you want to do\n");
while ((read_size = recv(sock, client_message, 2000, 0)) > 0)
{
client_message[read_size] = '\0';
write_sock(sock, client_message);
printf("User Entered:%s\n", client_message);
int pin = client_message[0]-'0';
int status = client_message[1]-'0';
lightLED(pin, status);
}
if (read_size == 0)
{
puts("Client Disconnected\n");
fflush(stdout);
totalConnections--;
}
else if (read_size == -1)
{
perror("recv Failed");
}
free(socket_desc);
return 0;
}
void lightLED(int pin, int status)
{
// if (wiringPiSetup() == -1)
// {
// puts("wiringPi Error");
// exit(1);
// }
printf("Changing LED Pin %d status %d\n", pin, status);
}