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oob_recv.c
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oob_recv.c
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#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <fcntl.h>
#define BUF_SIZE 30
void error_handling(char *message);
void urg_handler(int signo);
int acpt_sock;
int recv_sock;
int main(int argc, char *argv[])
{
struct sockaddr_in recv_adr, serv_adr;
int str_len, state;
socklen_t serv_adr_sz;
struct sigaction act;
char buf[BUF_SIZE];
if (argc != 2)
{
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
act.sa_handler = urg_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
acpt_sock = socket(PF_INET, SOCK_STREAM, 0);
memset(&recv_adr, 0, sizeof(recv_adr));
recv_adr.sin_family = AF_INET;
recv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
recv_adr.sin_port = htons(atoi(argv[1]));
if (bind(acpt_sock, (struct sockaddr *)&recv_adr, sizeof(recv_adr)) == -1)
error_handling("bind() error");
listen(acpt_sock, 5);
serv_adr_sz = sizeof(serv_adr);
recv_sock = accept(acpt_sock, (struct sockaddr *)&serv_adr, &serv_adr_sz);
//将文件描述符 recv_sock 指向的套接字拥有者(F_SETOWN)改为把getpid函数返回值用做id的进程
fcntl(recv_sock, F_SETOWN, getpid());
state = sigaction(SIGURG, &act, 0); //SIGURG 是一个信号,当接收到 MSG_OOB 紧急消息时,系统产生SIGURG信号
while ((str_len = recv(recv_sock, buf, sizeof(buf), 0)) != 0)
{
if (str_len == -1)
continue;
buf[str_len] = 0;
puts(buf);
}
close(recv_sock);
close(acpt_sock);
return 0;
}
void urg_handler(int signo)
{
int str_len;
char buf[BUF_SIZE];
str_len = recv(recv_sock, buf, sizeof(buf) - 1, MSG_OOB);
buf[str_len] = 0;
printf("Urgent message: %s \n", buf);
}
void error_handling(char *message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}