here is the code<\/p>\n\n\n\n
#include <unistd.h>\n#include <pthread.h>\n#include <arpa\/inet.h>\n#include <netinet\/in.h>\n#include <sys\/socket.h>\n#include <sys\/epoll.h>\n#include <fcntl.h>\n#include <string>\n#include <sys\/wait.h>\n#include <iostream>\n#include <syslog.h>\n#include <signal.h>\nusing std::cout;\nusing std::endl;\nbool stopflag = false;\nvoid handlesignal(int signum)\n{\n if(signum==SIGTERM)\n {\n stopflag = true;\n }\n}\nint setnonblocking(int fd)\n{\n int old_option = fcntl(fd,F_GETFL);\n int new_option = old_option|O_NONBLOCK;\n fcntl(fd,F_SETFL,new_option);\n return old_option;\n}\nvoid addtoepoll(int epfd,int fd)\n{\n setnonblocking(fd);\n epoll_event event;\n event.events = EPOLLIN;\n event.data.fd = fd;\n epoll_ctl(epfd,EPOLL_CTL_ADD,fd,&event);\n}\nstd::string getdatestring()\n{\n int p[2];\n pipe(p);\n int ret;\n if((ret=fork())==0)\n {\n close(STDOUT_FILENO);\n dup(p[1]);\n execl(\"\/usr\/bin\/date\",\"date\",nullptr);\n exit(-1);\n }\n else\n {\n waitpid(ret,nullptr,0);\n char buf[500];\n int l = read(p[0],buf,500);\n return std::string(buf,l);\n }\n}\nvoid set_reuse_addr(int fd)\n{\n int option = 1;\n setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&option,sizeof(option));\n}\nint main()\n{\n daemon(0,0);\n signal(SIGTERM,handlesignal);\n openlog(\"my_daytime_server\",LOG_PID,LOG_USER);\n setlogmask(LOG_UPTO(LOG_DEBUG));\n int listen_tcp_fd = socket(AF_INET,SOCK_STREAM,0);\n int listen_udp_fd = socket(AF_INET,SOCK_DGRAM,0);\n set_reuse_addr(listen_tcp_fd);\n set_reuse_addr(listen_udp_fd);\n if(listen_tcp_fd<0||listen_udp_fd<0)\n {\n perror(\"create socket failed\");\n return -1;\n }\n sockaddr_in local_addr;\n local_addr.sin_port = htons(13);\n local_addr.sin_family=AF_INET;\n inet_aton(\"0.0.0.0\",&local_addr.sin_addr);\n int ret = bind(listen_tcp_fd,(sockaddr*)&local_addr,sizeof(local_addr));\n if(ret<0)\n {\n perror(\"bind tcp socket failed\");\n return -1;\n }\n ret = bind(listen_udp_fd,(sockaddr*)&local_addr,sizeof(local_addr));\n if(ret<0)\n {\n perror(\"bind udp socket failed\");\n return -1;\n }\n listen(listen_tcp_fd,5);\n int epollfd = epoll_create(1);\n addtoepoll(epollfd,listen_tcp_fd);\n addtoepoll(epollfd,listen_udp_fd);\n epoll_event events[20];\n\n while(!stopflag)\n {\n ret = epoll_wait(epollfd,events,20,-1);\n for(int i=0;i<ret;i++)\n {\n int fd = events[i].data.fd;\n sockaddr_in client_addr;\n socklen_t length = sizeof(client_addr);\n std::string s = getdatestring();\n if(fd==listen_tcp_fd)\n {\n int client_fd = accept(fd,(sockaddr*)&client_addr,&length);\n syslog(LOG_USER|LOG_INFO,\"recv tcp connection from %s:%d\",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));\n send(client_fd,s.c_str(),s.length(),0);\n close(client_fd);\n }\n else if(fd==listen_udp_fd)\n {\n char buffer[1024];\n recvfrom(listen_udp_fd,buffer,1024,0,(sockaddr*)&client_addr,&length);\n syslog(LOG_USER|LOG_INFO,\"recv udp package from %s:%d\",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));\n sendto(listen_udp_fd,s.c_str(),s.length(),0,(sockaddr*)&client_addr,length);\n }\n }\n }\n closelog();\n syslog(LOG_USER|LOG_INFO,\"server exit normally by sigterm signal\");\n return 0;\n}<\/code><\/pre>\n\n\n\nsince i’m not familar with the behavior of accept function under et mode, so i choose lt mode. <\/p>\n","protected":false},"excerpt":{"rendered":"