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1高并发服务器:多进程服务器

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1多进程并发服务器

使用多进程并发服务器时要考虑以下几点:

A.父最大文件描述个数(父进程中需要close关闭accept返回的新文件描述符)

B.系统内创建进程个数(和内存大小相关)

C.进程创建过多是否降低整体服务性能(进程调度)

2.案例说明

server.c,代码如下:

#include <stdio.h>

#include <string.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <signal.h>

#include <sys/wait.h>

#include <sys/types.h>

#include <arpa/inet.h>

#include <ctype.h>

#include <unistd.h>

#include "wrap.h"

 

#define MAXLINE 80

#define SERV_PORT 8000

 

void do_sigchild(int num) {

    waitpid(0,NULL,WNOHANG);

}

 

int main(void) {

    struct sockaddr_in servaddr,cliaddr;

    socklen_t cliaddr_len;

    int listenfd,connfd;

    char buf[MAXLINE];

    //INET_ADDRSTRLENip地址的最大长度,是系统定义的一个宏

    char str[INET_ADDRSTRLEN];

    int i,n;

    pid_t pid;

 

    struct sigaction newact;

    newact.sa_handler = do_sigchild;

    sigemptyset(&newact.sa_mask);

    newact.sa_flags = 0;

    //发信号

    sigaction(SIGCHLD,&newact,NULL);

 

    //1.这里建立一个TCP的连接,因为是SOCK_STREAM的,表示的是TCP

    listenfd = Socket(AF_INET,SOCK_STREAM,0);

    //seraddr内容清零

    bzero(&servaddr,sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    servaddr.sin_port = htons(SERV_PORT);

    //2.绑定ip地址和端口号

    Bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));

    //监听,最多的可以是20

    Listen(listenfd,20);

   

    printf("Accepting connections...\n");

    while(1) {

        cliaddr_len = sizeof(cliaddr_len);

        //connfd:这里才是后续进程需要用的文件描述符

        //listenfd:已经不用里,可以被销毁,这个程序是在子进程里面销毁

        connfd = Accept(listenfd,(struct sockaddr *)&cliaddr,&cliaddr_len);

 

        pid = fork();

        if(pid ==0) {

            if(pid == 0) {

                Close(listenfd);

                while(1) {

                    n = Read(connfd,buf,MAXLINE);

                    if(n == 0) {

                        printf("the other side has been closed.\n");

                        break;

                    }

                    printf("received from %s at PORT %d\n",

                        inet_ntop(AF_INET,&cliaddr.sin_addr.s_addr,str,sizeof(str)),

                        ntohs(cliaddr.sin_port));

                   

                    for(i = 0; i< n; i++) {

                        buf[i] = toupper(buf[i]);

                    }

                    Write(connfd,buf,n);

                }

                Close(connfd);

                return 0;

            } else if(pid > 0) {

                Close(connfd);

            } else {

                perr_exit("fork");

            }

        }

    }

}

client.c

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <netinet/in.h>

#include <arpa/inet.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.s_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 ben closed.\n");

        } else {

            Write(STDOUT_FILENO,buf,n);

        }

    }

 

    Close(sockfd);

    return 0;

}

wrap.h

#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

#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 == EINTR))

                            goto again;

                   else

                            perr_exit("accept error");

         }

         return n;

}

 

void Bind(int fd, const struct sockaddr *sa, socklen_t salen)

{

         if (bind(fd, sa, salen) < 0)

                   perr_exit("bind error");

}

 

void Connect(int fd, const struct sockaddr *sa, socklen_t salen)

{

         if (connect(fd, sa, salen) < 0)

                   perr_exit("connect error");

}

 

void Listen(int fd, int backlog)

{

         if (listen(fd, backlog) < 0)

                   perr_exit("listen error");

}

 

int Socket(int family, int type, int protocol)

{

         int n;

 

         if ( (n = socket(family, type, protocol)) < 0)

                   perr_exit("socket error");

         return n;

}

 

ssize_t Read(int fd, void *ptr, size_t nbytes)

{

         ssize_t n;

 

again:

         if ( (n = read(fd, ptr, nbytes)) == -1) {

                   if (errno == EINTR)

                            goto again;

                   else

                            return -1;

         }

         return n;

}

 

ssize_t Write(int fd, const void *ptr, size_t nbytes)

{

         ssize_t n;

 

again:

         if ( (n = write(fd, ptr, nbytes)) == -1) {

                   if (errno == EINTR)

                            goto again;

                   else

                            return -1;

         }

         return n;

}

 

void Close(int fd)

{

         if (close(fd) == -1)

                   perr_exit("close error");

}

ssize_t Readn(int fd, void *vptr, size_t n)

{

         size_t  nleft;

         ssize_t nread;

         char   *ptr;

 

         ptr = vptr;

         nleft = n;

         while (nleft > 0) {

                   if ( (nread = read(fd, ptr, nleft)) < 0) {

                            if (errno == EINTR)

                                     nread = 0;

                            else

                                     return -1;

                   } else if (nread == 0)

                            break;

 

                   nleft -= nread;

                   ptr += nread;

         }

         return n - nleft;

}

 

ssize_t Writen(int fd, const void *vptr, size_t n)

{

         size_t nleft;

         ssize_t nwritten;

         const char *ptr;

 

         ptr = vptr;

         nleft = n;

         while (nleft > 0) {

                   if ( (nwritten = write(fd, ptr, nleft)) <= 0) {

                            if (nwritten < 0 && errno == EINTR)

                                     nwritten = 0;

                            else

                                     return -1;

                   }

 

                   nleft -= nwritten;

                   ptr += nwritten;

         }

         return n;

}

static ssize_t my_read(int fd, char *ptr)

{

         static int read_cnt;

         static char *read_ptr;

         static char read_buf[100];

 

         if (read_cnt <= 0) {

again:

                   if ( (read_cnt = read(fd, read_buf, sizeof(read_buf))) < 0) {

                            if (errno == EINTR)

                                     goto again;

                            return -1;

                   } else if (read_cnt == 0)

                            return 0;

                   read_ptr = read_buf;

         }

         read_cnt--;

         *ptr = *read_ptr++;

         return 1;

}

 

ssize_t Readline(int fd, void *vptr, size_t maxlen)

{

         ssize_t n, rc;

         char    c, *ptr;

 

         ptr = vptr;

         for (n = 1; n < maxlen; n++) {

                   if ( (rc = my_read(fd, &c)) == 1) {

                            *ptr++ = c;

                            if (c  == ‘\n‘)

                                     break;

                   } else if (rc == 0) {

                            *ptr = 0;

                            return n - 1;

                   } else {

                            return -1;

        }

         }

         *ptr  = 0;

         return n;

}

运行结果(编译server):

bubuko.com,布布扣

运行client

bubuko.com,布布扣

 

 

 

 

 

1高并发服务器:多进程服务器

标签:style   blog   http   color   io   os   使用   ar   for   

原文地址:http://blog.csdn.net/tototuzuoquan/article/details/39621823

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