在运行此代码时，我没有看到再见，只要我输入'Hello'就会以'非套接字上的套接字操作'作为错误终止。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）及以上的消息，而不能看到第一个消息。并且在显示消息后终止连接，否则就是等待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;
}
//新代码被修改，一旦通过读取stdin数据然后它不响应任何其他连接可能由于阻塞请帮助
#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;
}
答案 0 :(得分：3)
这实际上是一个linux问题，因为你试图使用recv和send来读取和写入STDIN（可能是终端而不是套接字）。与大多数UNIX变体不同，在Linux中，send和recv只能用于套接字，而不能用于任何文件描述符。对于终端，您需要使用read和write。
还有一个问题是写入STDIN很奇怪 - 通常只读取STDIN并写入STDOUT。但只要STDIN像你可以写的终端那样，就可以了。