1多線程并發服務器
在使用線程模型開發服務器時需要考慮以下問題：
A調整進程最大文件描述符上限
B線程如有共享數據，考慮線程同步
C服務于客戶端線程退出時，退出處理。（退出值，分離態）
D系統負載，隨著連接客戶端增加，導致其它線程不能及時得到CPU
2.案例說明
server.c,代碼如下：
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/* server.c */ #include <stdio.h> #include <string.h> #include <netinet/in.h> #include <arpa/inet.h> #include <pthread.h> #include "wrap.h" #define MAXLINE 80 #define SERV_PORT 8000
struct s_info { struct sockaddr_in cliaddr; int connfd; };
void *do_work(void *arg) { int n,i; struct s_info *ts = (struct s_info*)arg; char buf[MAXLINE]; char str[INET_ADDRSTRLEN]; /*可以在創建線程前設置線程創建屬性,設為分離態,哪種效率高內？ 答：線程前設置線程屬性*/ pthread_detach(pthread_self()); while (1) { n = Read(ts->connfd, buf, MAXLINE); if (n == 0) { printf("the other side has been closed. "); break; } printf("received from %s at PORT %d ", inet_ntop(AF_INET, &(*ts).cliaddr.sin_addr, str, sizeof(str)), ntohs((*ts).cliaddr.sin_port)); for (i = 0; i < n; i++) { buf[i] = toupper(buf[i]); } Write(ts->connfd, buf, n); } Close(ts->connfd); }
int main(void) { struct sockaddr_in servaddr, cliaddr; socklen_t cliaddr_len; int listenfd, connfd; int i = 0; pthread_t tid; struct s_info ts[383]; listenfd = Socket(AF_INET, SOCK_STREAM, 0); bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = htonl(INADDR_ANY); servaddr.sin_port = htons(SERV_PORT); Bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)); Listen(listenfd, 20); printf("Accepting connections ... "); while (1) { cliaddr_len = sizeof(cliaddr); connfd = Accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len); ts[i].cliaddr = cliaddr; ts[i].connfd = connfd; /*達到線程最大數時，pthread_create出錯處理,增加服務器穩定性*/ pthread_create(&tid, NULL, do_work, (void*)&ts[i]); i++; } return 0; } |
client.c
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/* client.c */ #include <stdio.h> #include <string.h> #include <unistd.h> #include <netinet/in.h> #include "wrap.h" #define MAXLINE 80 #define SERV_PORT 8000 int main(int argc, char *argv[]) { struct sockaddr_in servaddr; char buf[MAXLINE]; int sockfd, n; sockfd = Socket(AF_INET, SOCK_STREAM, 0); bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr); servaddr.sin_port = htons(SERV_PORT); Connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)); while (fgets(buf, MAXLINE, stdin) != NULL) { Write(sockfd, buf, strlen(buf)); n = Read(sockfd, buf, MAXLINE); if (n == 0) printf("the other side has been closed. "); else Write(STDOUT_FILENO, buf, n); } Close(sockfd); return 0; } |
wrap.h
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#ifndef __WRAP_H_ #define __WRAP_H_
void perr_exit(const char *s); int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr); void Bind(int fd, const struct sockaddr *sa, socklen_t salen); void Connect(int fd, const struct sockaddr *sa, socklen_t salen); void Listen(int fd, int backlog); int Socket(int family, int type, int protocol); ssize_t Read(int fd, void *ptr, size_t nbytes); ssize_t Write(int fd, const void *ptr, size_t nbytes); void Close(int fd); ssize_t Readn(int fd, void *vptr, size_t n); ssize_t Writen(int fd, const void *vptr, size_t n); static ssize_t my_read(int fd, char *ptr); ssize_t Readline(int fd, void *vptr, size_t maxlen);
#endif |
wrap.c
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#include <stdlib.h> #include <errno.h> #include <sys/socket.h>
void perr_exit(const char *s) { perror(s); exit(1); }
int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr) { int n;
again: if ( (n = accept(fd, sa, salenptr)) < 0) { if ((errno == ECONNABORTED) || (errno 程序員人生，我編程，我富裕，記住wfuyu網，php教程，php學習，php手冊，CMS模版制作 聲明：本站大部分內容是作者原創，少部分收集于互聯網供大家一起學習，原版權很多不明，如有侵權請聯系本站，謝謝！
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