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socket绑定问题
我面试写的程序，希望能帮上点忙
/* For this example, server.c,
we call fork() to deal with more clients in a time,
if we deal with client one by one,then every 2 senconds deal with one client;
client will send ABC ; we echo with BCD */
#include <sys/types.h>;
#include <sys/socket.h>;
#include <stdio.h>;
#include <netinet/in.h>;
#include <sys/time.h>;
#include <sys/ioctl.h>;
#include <unistd.h>;
int main()
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
int result,pid;
fd_set readfds, testfds;
/* Create and name a socket for the server. */
server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr = htonl(INADDR_ANY);
server_address.sin_port = htons(9734);
server_len = sizeof(server_address);
bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
/* Create a connection queue and initialize readfds to handle input from server_sockfd. */
listen(server_sockfd, 5);
FD_ZERO(&readfds);
FD_SET(server_sockfd, &readfds);
/* Now wait for clients and requests.
Since we have passed a null pointer as the timeout parameter, no timeout will occur.
The program will exit and report an error if select returns a value of less than 1. */
while(1) {
char ch;
int fd;
int nread;
testfds = readfds;
printf("server waiting\n" ;
result = select(FD_SETSIZE, &testfds, (fd_set *)0,
(fd_set *)0, (struct timeval *) 0);
if(result < 1) {
perror("server";
exit(1);
}
/* Once we know we've got activity,
we find which descriptor it's on by checking each in turn using FD_ISSET. */
for(fd = 0; fd < FD_SETSIZE; fd++) {
if(FD_ISSET(fd,&testfds)) {
/* If the activity is on server_sockfd, it must be a request for a new connection
and we add the associated client_sockfd to the descriptor set. */
if(fd == server_sockfd) {
client_len = sizeof(client_address);
client_sockfd = accept(server_sockfd,
(struct sockaddr *)&client_address, &client_len);
/*if create process faild;drop*/
if((pid=fork())==-1)
{
close(client_sockfd);
continue;
}
else if(pid>;0)
/*father process*/
{
close(client_sockfd);
continue;
}
else
/*child */
{
FD_SET(client_sockfd, &readfds);
printf("adding client on fd %d\n", client_sockfd);
}
}
/* If it isn't the server, it must be client activity.
If close is received, the client has gone away and we remove it from the descriptor set.
Otherwise, we 'serve' the client as in the previous examples. */
else {
ioctl(fd, FIONREAD, &nread);
if(nread == 0) {
close(fd);
FD_CLR(fd, &readfds);
printf("removing client on fd %d\n", fd);
}
else {
read(fd, &ch, 1);
sleep(2);
printf("serving client on fd %d\n", fd);
ch++;
write(fd, &ch, 1);
}
}
}
}
}
}
* Make the necessary includes and set up the variables. */
#include <sys/types.h>;
#include <sys/socket.h>;
#include <stdio.h>;
#include <netinet/in.h>;
#include <arpa/inet.h>;
#include <unistd.h>;
int main()
{
int sockfd;
int len;
struct sockaddr_in address;
int result;
char ch = 'A';
/* Create a socket for the client. */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
/* Name the socket, as agreed with the server. */
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr("127.0.0.1";
address.sin_port = htons(9734);
len = sizeof(address);
/* Now connect our socket to the server's socket. */
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1) {
perror("oops: client";
exit(1);
}
/* We can now read/write via sockfd. */
write(sockfd, &ch, 1);
read(sockfd, &ch, 1);
printf("char from server = %c\n", ch);
close(sockfd);
exit(0);
} |
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发表于 2005-03-29 12:02
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