标签：pid nbsp nis src 缓冲 connect int sock ++
1、recv、read
recv和read的区别？？ recv只能用于套接口io，不能用于文件io或者其他io read可以用于各种io
recv相较而言多了flag参数，MSG_OOB（接收紧急数据指针）MSG_PEEK（接收缓冲区数据，但是并不急着清除）
2、封装按行读取readline
3、getsockname可以看到本机client针对已连接conn生成的ip和port
4、gethostname可以获取本机主机名/gethostbyname可以获取本机所有ip列表
#include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> #define ERR_EXIT(m) do { perror(m); exit(EXIT_FAILURE); } while(0) ssize_t readn(int fd, void *buf, size_t count){ size_t nleft = count; ssize_t nread; char *bufp = (char*)buf; while(nleft > 0){ if((nread = read(fd, bufp, nleft)) < 0){ if(errno == EINTR) continue; return -1; } else if (nread == 0){ return count - nleft; } bufp += nread; nleft -= nread; } return count; } ssize_t writen(int fd, void *buf, size_t count){ size_t nleft = count; ssize_t nwritten; char *bufp = (char*)buf; while(nleft > 0){ if((nwritten = write(fd, bufp, nleft)) < 0){ if(errno == EINTR) continue; return -1; } else if (nwritten == 0){ continue; } bufp += nwritten; nleft -= nwritten; } return count; } ssize_t recv_peek(int sockfd, void* buf, size_t len){ while(1){ int ret = recv(sockfd, buf, len, MSG_PEEK); if(ret == -1 && errno == EINTR) continue; return ret; } } //按行读取 ssize_t readline(int sockfd, void* buf, size_t maxline){ int ret; int nread; char *bufp = buf; int nleft = maxline; while(1){ ret = recv_peek(sockfd, bufp, nleft); if(ret < 0) return ret; else if(ret == 0){ return ret; } nread = ret; int i; for(i = 0; i<nread; i++){ if(bufp[i] == ‘\n‘){ ret = readn(sockfd, bufp, i+1); if(ret != i+1){ exit(EXIT_FAILURE); } return ret; } } if(nread > nleft) exit(EXIT_FAILURE); nleft -= nread; ret = readn(sockfd, bufp, nread); if(ret != nread) exit(EXIT_FAILURE); bufp += nread; } return -1; } void do_service(int conn){ char recvbuf[1024]; while(1){ memset(recvbuf, 0, sizeof(recvbuf)); int ret = readline(conn, recvbuf, 1024); if (ret == -1){ ERR_EXIT("readn...4"); }else if(ret == 0){ printf("client close\n"); break; } fputs(recvbuf, stdout); writen(conn, recvbuf, strlen(recvbuf)); } } int main(void){ int listenfd; if ((listenfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) ERR_EXIT("socket"); struct sockaddr_in servaddr; memset(&servaddr, 0, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = htons(5188); servaddr.sin_addr.s_addr = htonl(INADDR_ANY); int on = 1; if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0){ ERR_EXIT("setsockopt"); } if (bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){ ERR_EXIT("bind"); } if (listen(listenfd, SOMAXCONN) < 0) ERR_EXIT("listen"); int conn; struct sockaddr_in peeraddr; socklen_t peerlen = sizeof(peeraddr); pid_t pid; while(1){ if ((conn = accept(listenfd, (struct sockaddr*)&peeraddr, &peerlen)) < 0) ERR_EXIT("accept"); printf("ip=%s prot=%d\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port)); pid = fork(); if(pid == -1) ERR_EXIT("fork"); if(pid == 0){ close(listenfd); do_service(conn); exit(EXIT_SUCCESS); } else { close(conn); } } return 0; }
#include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> #define ERR_EXIT(m) do { perror(m); exit(EXIT_FAILURE); } while(0) ssize_t readn(int fd, void *buf, size_t count){ size_t nleft = count; ssize_t nread; char *bufp = (char*)buf; while(nleft > 0){ if((nread = read(fd, bufp, nleft)) < 0){ if(errno == EINTR) continue; return -1; } else if (nread == 0){ return count - nleft; } bufp += nread; nleft -= nread; } return count; } ssize_t writen(int fd, void *buf, size_t count){ size_t nleft = count; ssize_t nwritten; char *bufp = (char*)buf; while(nleft > 0){ if((nwritten = write(fd, bufp, nleft)) < 0){ if(errno == EINTR) continue; return -1; } else if (nwritten == 0){ continue; } bufp += nwritten; nleft -= nwritten; } return count; } ssize_t recv_peek(int sockfd, void* buf, size_t len){ while(1){ int ret = recv(sockfd, buf, len, MSG_PEEK); if(ret == -1 && errno == EINTR) continue; return ret; } } //按行读取 ssize_t readline(int sockfd, void* buf, size_t maxline){ int ret; int nread; char *bufp = buf; int nleft = maxline; while(1){ ret = recv_peek(sockfd, bufp, nleft); if(ret < 0) return ret; else if(ret == 0){ return ret; } nread = ret; int i; for(i = 0; i<nread; i++){ if(bufp[i] == ‘\n‘){ ret = readn(sockfd, bufp, i+1); if(ret != i+1){ exit(EXIT_FAILURE); } return ret; } } if(nread > nleft) exit(EXIT_FAILURE); nleft -= nread; ret = readn(sockfd, bufp, nread); if(ret != nread) exit(EXIT_FAILURE); bufp += nread; } return -1; } int main(void){ int sock; if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) ERR_EXIT("socket"); struct sockaddr_in servaddr; memset(&servaddr, 0, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = htons(5188); servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); if (connect(sock, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0) ERR_EXIT("connect"); struct sockaddr_in localaddr; socklen_t addrlen = sizeof(localaddr); if (getsockname(sock, (struct sockaddr*)&localaddr, &addrlen) < 0){ ERR_EXIT("getsockname"); } printf("ip=%s prot=%d\n", inet_ntoa(localaddr.sin_addr), ntohs(localaddr.sin_port)); char sendbuf[1024] = {0}; char recvbuf[1024] = {0}; while(fgets(sendbuf, sizeof(sendbuf), stdin) != NULL){ writen(sock, sendbuf, strlen(sendbuf)); int ret = readline(sock, recvbuf, sizeof(recvbuf)); if (ret == -1){ ERR_EXIT("readline"); }else if(ret == 0){ printf("client close\n"); break; } fputs(recvbuf, stdout); memset(sendbuf, 0, sizeof(sendbuf)); memset(recvbuf, 0, sizeof(recvbuf)); } close(sock); return 0; }
#include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> #define ERR_EXIT(m) do { perror(m); exit(EXIT_FAILURE); } while(0) int getlocalip(char *ip){ char host[100] = {0}; if(gethostname(host, sizeof(host)) < 0){ ERR_EXIT("gethostname"); } struct hostent *hp; if((hp = gethostbyname(host)) == NULL) ERR_EXIT("gethostbyname"); strcpy(ip, inet_ntoa(*(struct in_addr*)hp->h_addr_list[0])); return 0; } int main(void){ char host[100] = {0}; if(gethostname(host, sizeof(host)) < 0){ ERR_EXIT("gethostname"); } printf("host:%s\n", host); struct hostent *hp; if((hp = gethostbyname(host)) == NULL) ERR_EXIT("gethostbyname"); int i=0; while(hp->h_addr_list[i] != NULL){ printf("%s\n", inet_ntoa(*(struct in_addr*)hp->h_addr_list[i])); i++; } char ip[16] = {0}; getlocalip(ip); printf("localip=%s\n", ip); return 0; }
.PHONY:clean all CC=gcc CFLAGS=-Wall -g BIN=echosrv echocli getiplist all:$(BIN) %.o:%.c $(CC) $(CFLAGS) -c $C -o $@ clean: rm -f *.o $(BIN)
标签：pid nbsp nis src 缓冲 connect int sock ++
原文地址：https://www.cnblogs.com/bailuoxi/p/12730805.html
