0

在运行此代码时，当我输入“Hello”时，我没有看到打印的再见，它以“非套接字上的套接字操作”作为错误终止。此外，当我从客户端发送消息时（使用 localhost ubuntu/多个控制台）。我只能看到来自第二个控制台（客户端）及更高版本的消息，但不能看到来自第一个控制台的消息。并且在显示消息后终止连接，否则对于它只是等待的第一个客户端的情况。

c中的服务器代码

#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#define PORT "3490"
#define STDIN  0
#define STDOUT 1
char *opt;

void *get_in_addr(struct sockaddr *sa)
{
    if (sa->sa_family == AF_INET) {
        return &(((struct sockaddr_in*)sa)->sin_addr);
    }
    return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
int main(void)
{
    fd_set master;
    fd_set read_fds;
    int fdmax;
    // master file descriptor list
    // temp file descriptor list for select()
    // maximum file descriptor number
    int listener;
    // listening socket descriptor
    int newfd;
    // newly accept()ed socket descriptor
    struct sockaddr_storage remoteaddr; // client address
    socklen_t addrlen;
    char buf[256];
    int nbytes;
    // buffer for client data
    char remoteIP[INET6_ADDRSTRLEN];
    int yes=1;
    int i, j, rv;
    // for setsockopt() SO_REUSEADDR, below
    struct addrinfo hints, *ai, *p;
    FD_ZERO(&master);
    FD_ZERO(&read_fds);
    // clear the master and temp sets
    // get us a socket and bind it
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;
    if ((rv = getaddrinfo(NULL, PORT, &hints, &ai)) != 0) {
        fprintf(stderr, "selectserver: %s\n", gai_strerror(rv));
        exit(1);
    }
    for(p = ai; p != NULL; p = p->ai_next) {
        listener = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
        if (listener < 0) {
            continue;
        }
        // lose the pesky "address already in use" error message
        setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
        if (bind(listener, p->ai_addr, p->ai_addrlen) < 0) {
            close(listener);
            continue;
        }

        break;
    }
    // if we got here, it means we didn't get bound
    if (p == NULL) {
        fprintf(stderr, "selectserver: failed to bind\n");
        exit(2);
    }
    freeaddrinfo(ai); // all done with this
    // listen
    if (listen(listener, 10) == -1) {
        perror("listen");
        exit(3);
    }
    // add the listener to the master set
    FD_SET(listener, &master);
    FD_SET(STDIN,&master);
    // keep track of the biggest file descriptor
    fdmax = listener; // so far, it's this one
    // main loop
    for(;;) {
        read_fds = master; // copy it
        if (select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1) {
            perror("select");
            exit(4);
        }
        // run through the existing connections looking for data to read
        for(i = 0; i <= fdmax; i++) {
            if (FD_ISSET(i, &read_fds)) { // we got one!!
            if (i == listener) {
                // handle new connections
                addrlen = sizeof remoteaddr;
                newfd = accept(listener,
                               (struct sockaddr *)&remoteaddr,
                               &addrlen);
                if (newfd == -1) {
                    perror("accept");
                } else {
                FD_SET(newfd, &master); // add to master set
                if (newfd > fdmax) {
                    // keep track of the max
                    fdmax = newfd;
                }
                printf("selectserver: new connection from %s on "
                       "socket %d\n",inet_ntop(remoteaddr.ss_family,
                        get_in_addr((struct sockaddr*)&remoteaddr),
                        remoteIP, INET6_ADDRSTRLEN),
                        newfd);
                }
            } else {

                // handle data from a client
                if ((nbytes = recv(i, buf, sizeof buf, 0)) <= 0) {
                    // got error or connection closed by client
                    if (nbytes == 0) {
                        // connection closed

                        printf("selectserver: socket %d hung up\n", i);
                    } else {
                        perror("recv");
                    }
                    close(i); // bye!
                    FD_CLR(i, &master); // remove from master set
                } else {
                    if(i==STDIN){
                        printf("Goodbye");
                    }
                    // we got some data from a client
                    for(j = 0; j <= fdmax; j++) {
                        // send to everyone!
                        if (FD_ISSET(j, &master)) {
                            // except the listener and ourselves
                            if (j != listener && j != i) {
                                if (send(j, buf, nbytes, 0) == -1) {
                                    perror("send");
                                }

                            }
                        }
                    }
                }
            } // END handle data from client
            } // END got new incoming connection
        } // END looping through file descriptors
    } // END for(;;)--and you thought it would never end!
    return 0;
}

//新代码修改，一旦读取标准输入数据，它就不会响应任何其他连接，可能是由于阻塞请帮助

    #include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/time.h>


#define TRUE 1
#define FALSE 0

//Var
int mode,info;
int PORT;

char *ip_host;
int i,len,rc,on=1;
int listen_sd,max_sd,new_sd;
int desc_ready,end_server=FALSE;
int close_conn;
char buffer[256];
//struct sockaddr_in  addr;
struct timeval timeout;
fd_set master_set,working_set;
struct sockaddr_storage remoteaddr; // client addres//s
socklen_t addrlen;
char remoteIP[INET6_ADDRSTRLEN];
char s[INET6_ADDRSTRLEN];
struct addrinfo hints, *loadinfo, *ptr;


void *get_in_addr(struct sockaddr *sa)
{
if (sa->sa_family == AF_INET) {
return &(((struct sockaddr_in*)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}


void servcl_memset(){
memset(&hints, 0, sizeof(hints));
hints.ai_family= AF_UNSPEC;
hints.ai_socktype= SOCK_STREAM;
}

void cl_connect()
{
for(ptr = loadinfo; ptr != NULL; ptr = ptr->ai_next) {
  if ((listen_sd = socket(ptr->ai_family, ptr->ai_socktype,ptr->ai_protocol)) == -1) {
  perror("client: socket");
  continue;
  }

 if (connect(listen_sd, ptr->ai_addr, ptr->ai_addrlen) == -1) {
 close(listen_sd);
 perror("client: connect");
 continue;
 }

break;
}

if (ptr == NULL) {
fprintf(stderr, "client: failed to connect(bind)\n");
exit(0);
}
inet_ntop(ptr->ai_family, get_in_addr((struct sockaddr *)ptr->ai_addr),s, sizeof s);
printf("client: connecting to %s\n", s);
freeaddrinfo(loadinfo); // all done with this structure
}



void init_socket(){
for(ptr = loadinfo; ptr != NULL; ptr = ptr->ai_next) {

if ((listen_sd = socket(ptr->ai_family, ptr->ai_socktype,ptr->ai_protocol)) == -1) {
perror("server: socket");
continue;
}

rc = setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR,(char *)&on, sizeof(on));
if (rc < 0)
{
perror("setsockopt() failed");
close(listen_sd);
continue;
}

rc = bind(listen_sd,ptr->ai_addr,ptr->ai_addrlen);
if (rc < 0)
{
perror("bind() failed");
close(listen_sd);
continue;
}
break;

}//End For

if (ptr == NULL) {
fprintf(stderr, "client/server: failed to connect(bind)\n");
exit(0);
}
freeaddrinfo(loadinfo); // all done with this structure
}

void unblock(){
rc = ioctl(listen_sd, FIONBIO, (char *)&on);
if (rc < 0)
{
perror("ioctl() failed");
close(listen_sd);
exit(-1);
}
}

void sock_listen(){
rc = listen(listen_sd, 32);
if (rc < 0)
{
perror("listen() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Initialize the master fd_set
*/
/*************************************************************/
FD_ZERO(&master_set);
max_sd = listen_sd;
FD_SET(0,&master_set);
FD_SET(listen_sd, &master_set);
}

void conn_timeout(){
timeout.tv_sec = 3 * 60;
timeout.tv_usec = 0;
}


/*void client_listen(){
do
{
memcpy(&working_set, &master_set, sizeof(master_set));
printf("Waiting on select()...\n");
rc = select(max_sd + 1, &working_set, NULL, NULL, &timeout);

if (rc < 0)
{
perror(" select() failed");
break;
}

if (rc == 0)
{
printf(" select() timed out. End program.\n");
break;
}

desc_ready = rc;
*/

void start_listen(){
do
{
memcpy(&working_set, &master_set, sizeof(master_set));
printf("Waiting on select()...\n");
rc = select(max_sd + 1, &working_set, NULL, NULL, &timeout);

if (rc < 0)
{
perror(" select() failed");
break;
}

if (rc == 0)
{
printf(" select() timed out. End program.\n");
break;
}

desc_ready = rc;
for (i=0; i <= max_sd && desc_ready > 0; ++i)
{
if (FD_ISSET(i, &working_set))
{
desc_ready -= 1;
if (i == listen_sd)
{
printf(" Listening socket is readable\n");

do
{
addrlen = sizeof remoteaddr;
new_sd = accept(listen_sd, (struct sockaddr *)&remoteaddr,&addrlen);
if (new_sd < 0)
{
if (errno != EWOULDBLOCK)
{
perror(" accept() failed");
end_server = TRUE;
}
break;
}

printf(" New incoming connection - %d\n", new_sd);
printf("selectserver: new connection from %s on "
"socket %d\n",
inet_ntop(remoteaddr.ss_family,
get_in_addr((struct sockaddr*)&remoteaddr),
remoteIP, INET6_ADDRSTRLEN),
new_sd);

FD_SET(new_sd, &master_set);
if (new_sd > max_sd)
max_sd = new_sd;
} while (new_sd != -1);
}

else
{
printf(" Descriptor %d is readable\n", i);
close_conn = FALSE;

//do
//{
rc = read(i, buffer, sizeof(buffer)-1);
if (rc < 0)
{
 if (errno != EWOULDBLOCK)
{
perror(" recv() failed");
close_conn = TRUE;
}
break;
}

if (rc == 0)
{
printf(" Connection closed\n");
close_conn = TRUE;
break;
}

len = rc;
printf(" %d bytes received\n", len);
if (i==0)i=1;
rc = write(i, buffer, len);
if (i==1)i=0;
if (rc < 0)
{
perror(" send() failed");
close_conn = TRUE;
break;
}
//} while (TRUE);

if (close_conn)
{
close(i);
FD_CLR(i, &master_set);
if (i == max_sd)
{
while (FD_ISSET(max_sd, &master_set) == FALSE)
max_sd -= 1;
}
}
} /* End of existing connection is readable */
} /* End of if (FD_ISSET(i, &working_set)) */
} /* End of loop through selectable descriptors */
end_server==TRUE;} while (end_server == FALSE);
}

void conn_close(){
for (i=0; i <= max_sd; ++i)
{
if (FD_ISSET(i, &master_set))
close(i);
}
}


void cl_socket() {
printf("Please enter the message: ");
do
{
memcpy(&working_set, &master_set, sizeof(master_set));
printf("Waiting on select()...\n");
rc = select(max_sd + 1, &working_set, NULL, NULL,NULL);

if (rc < 0)
{
perror(" select() failed");
break;
}


desc_ready = rc;
for (i=0; i <= max_sd && desc_ready > 0; ++i)
{
 if (FD_ISSET(i, &working_set))
  {
    desc_ready -= 1;
    printf(" Descriptor %d is readable\n", i);
    close_conn = FALSE;
  do  
    {
    fgets(buffer,255,stdin);
    rc = write(listen_sd, buffer,strlen(buffer));
    if (rc < 0)
     {
      perror(" send() failed");
      close_conn = TRUE;
     }

    rc = read(listen_sd, buffer, sizeof(buffer)-1);
    if (rc < 0)
    {
     if (errno != EWOULDBLOCK)
       {
        perror(" recv() failed");
        close_conn = TRUE;
       }

     }

      if (rc == 0)
      {
      printf(" Connection closed\n");
      close_conn = TRUE;
      }

len = rc;
printf(" %d bytes received\n", len);
 } while (TRUE);

if (close_conn)
{
 close(i);
 FD_CLR(i, &master_set);
 if (i == max_sd)
 {
 while (FD_ISSET(max_sd, &master_set) == FALSE)
 max_sd -= 1;
 }
}

}//Working set
}//For loop

end_server==TRUE;} while (end_server == FALSE);

}

main(int argc,char * argv[])
{
mode=atoi(argv[1]);
PORT=atoi(argv[2]);
ip_host=(argv[3]);
servcl_memset();
 if (mode ==1){
               printf("In client mode\n");
           if ((info = getaddrinfo(argv[3], argv[2], &hints, &loadinfo)) != 0) {
           fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(info));
               return 1;
                    }
              cl_connect();  
              unblock();
              conn_timeout();
              cl_socket();
              conn_close();
              }
  else {
         printf("In server mode\n");
         hints.ai_flags=AI_PASSIVE;
         if ((info = getaddrinfo(NULL, argv[2], &hints, &loadinfo)) != 0) {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(info));
         return 1;
         }
         init_socket();
         unblock();
         sock_listen();
         conn_timeout();
         start_listen();
         conn_close();
       }

}



/*

*/

我还有另一个用于测试的客户端。

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

void error(const char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
    printf("Please enter the message: ");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0) 
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0) 
         error("ERROR reading from socket");
    printf("%s\n",buffer);
    close(sockfd);
    return 0;
}
4

1 回答 1

3

这实际上是一个 linux 问题，因为您正在尝试使用recv和send读取和写入 STDIN（这可能是终端而不是套接字）。与大多数 UNIX 变体不同，在 Linux 中，send只能recv在套接字上使用，而不能在任何文件描述符上使用。对于终端，您需要使用readand write。

还有一个问题是写入 STDIN 很奇怪——通常你只能从 STDIN 读取并写入 STDOUT。但只要 STDIN 是您可以写入的终端之类的东西，就可以了。

于 2013-09-12T05:31:56.970 回答