TCP->多进程服务器->多进程服务器->线程池

TCP流式套接字

makefile

.PHONY:allall : tcp_client tcp_servertcp_client : tcp_client.c    gcc - o $@ $^ -statictcp_server:tcp_server.c    gcc - o $@ $^.PHONY:cleanclean :    rm - f tcp_server tcp_client

tcp_server.c

#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>#include <stdlib.h>#include <string.h>static usage(const char *proc){    printf("Usage: %s [local_ip] [local_port]\n",proc);}int startup(const char *ip, int port){    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        exit(2);    }    printf("sock: %d\n",sock);    struct sockaddr_in local;    local.sin_family = AF_INET;    local.sin_port = htons(port);    local.sin_addr.s_addr = inet_addr(ip);//192.168.X.X    if(bind(sock,(struct sockaddr*)&local,sizeof(local)) < 0)    {        perror("bind");        exit(3);    }    if(listen(sock, 10) < 0)    {        perror("listen");        exit(4);    }    return sock;}//./tcp_server 192.18.X.X 8080int main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int listen_sock = startup(argv[1], atoi(argv[2]));    while(1)    {        struct sockaddr_in client;        socklen_t len = sizeof(client);        int new_sock = accept(listen_sock,(struct sockaddr*)&client, &len);        if(new_sock < 0)        {            perror("accept");            continue;        }        printf("get new client [%s:%d]\n",\                inet_ntoa(client.sin_addr),\                ntohs(client.sin_port));        //read ->write        while(1)        {            char buf[1024];            ssize_t s = read(new_sock, buf, sizeof(buf)-1);            if(s > 0)            {                buf[s] = 0;                printf("client# %s\n",buf);                write(new_sock, buf, strlen(buf));            }else if(s == 0)            {                printf("client close!!\n");                break;            }else            {                perror("read");                break;            }        }        close(new_sock);    }    return 0;}

tcp_client.c

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>static void usage(const char *proc){       printf("Usage: %s [server_ip] [server_port]\n",proc);}//./tcp_client server_ip server_portint main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        return 2;    }    struct sockaddr_in server;    server.sin_family = AF_INET;    server.sin_port = htons(atoi(argv[2]));    server.sin_addr.s_addr = inet_addr(argv[1]);    if(connect(sock,(struct sockaddr*)&server,sizeof(server)) < 0)    {        perror("connect");        return 3;    }    char buf[1024];    while(1)    {        printf("Please Enter#");        fflush(stdout);        ssize_t s = read(0, buf, sizeof(buf) - 1);        if(s > 0)        {            buf[s-1]= 0;            write(sock, buf, strlen(buf));            ssize_t _s = read(sock, buf, sizeof(buf)-1);            if(_s > 0)            {                buf[_s] = 0;                printf("server echo# %s\n",buf);            }        }    }    close(sock);    return 0;}

多进程服务器

makefile

.PHONY:allall:tcp_client tcp_servertcp_client:tcp_client.c    gcc -o $@ $^ -statictcp_server:tcp_server.c    gcc -o $@ $^.PHONY:cleanclean:    rm -f tcp_server tcp_client

tcp_server.c

#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>#include <stdlib.h>#include <string.h>static usage(const char *proc){    printf("Usage: %s [local_ip] [local_port]\n",proc);}int startup(const char *ip, int port){    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        exit(2);    }    printf("sock: %d\n",sock);    struct sockaddr_in local;    local.sin_family = AF_INET;    local.sin_port = htons(port);    local.sin_addr.s_addr = inet_addr(ip);//192.168.X.X    if(bind(sock,(struct sockaddr*)&local,sizeof(local)) < 0)    {        perror("bind");        exit(3);    }    if(listen(sock, 10) < 0)    {        perror("listen");        exit(4);    }    return sock;}//./tcp_server 192.18.X.X 8080int main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int listen_sock = startup(argv[1], atoi(argv[2]));    while(1)    {        struct sockaddr_in client;        socklen_t len = sizeof(client);        int new_sock = accept(listen_sock,(struct sockaddr*)&client, &len);        if(new_sock < 0)        {            perror("accept");            continue;        }        printf("get new client [%s:%d]\n",\                inet_ntoa(client.sin_addr),\                ntohs(client.sin_port));        pid_t id = fork();        if(id < 0)        {            perror("fork");            close(new_sock);        }        else if(id == 0)//child        {            close(listen_sock);            if(fork()> 0 )//child->father            {                exit(0);            }            //read ->write            while(1)            {            char buf[1024];            ssize_t s = read(new_sock, buf, sizeof(buf)-1);            if(s > 0)            {                buf[s] = 0;                printf("client# %s\n",buf);                write(new_sock, buf, strlen(buf));            }            else if(s == 0)            {                printf("client close!!\n");                break;            }            else            {                perror("read");            }        }            close(new_sock);            exit(0);        }        else//father        {            close(new_sock);            waitpid(id,NULL,0);        }    }    return 0;}

tcp_client.c

#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>static void usage(const char *proc){       printf("Usage: %s [server_ip] [server_port]\n",proc);}//./tcp_client server_ip server_portint main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        return 2;    }    struct sockaddr_in server;    server.sin_family = AF_INET;    server.sin_port = htons(atoi(argv[2]));    server.sin_addr.s_addr = inet_addr(argv[1]);    if(connect(sock,(struct sockaddr*)&server,sizeof(server)) < 0)    {        perror("connect");        return 3;    }    char buf[1024];    while(1)    {        printf("Please Enter#");        fflush(stdout);        ssize_t s = read(0, buf, sizeof(buf) - 1);        if(s > 0)        {            buf[s-1]= 0;            write(sock, buf, strlen(buf));            ssize_t _s = read(sock, buf, sizeof(buf)-1);            if(_s > 0)            {                buf[_s] = 0;                printf("server echo# %s\n",buf);            }        }    }    close(sock);    return 0;}

多线程服务器

makefile

.PHONY:allall:tcp_client tcp_servertcp_client:tcp_client.c    gcc -o $@ $^ -statictcp_server:tcp_server.c    gcc -o $@ $^ -lpthread.PHONY:cleanclean:    rm -f tcp_server tcp_client

tcp_server.c

#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>#include <stdlib.h>#include <string.h>#include <pthread.h>static usage(const char *proc){    printf("Usage: %s [local_ip] [local_port]\n",proc);}int startup(const char *ip, int port){    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        exit(2);    }    printf("sock: %d\n",sock);    struct sockaddr_in local;    local.sin_family = AF_INET;    local.sin_port = htons(port);    local.sin_addr.s_addr = inet_addr(ip);//192.168.X.X    if(bind(sock,(struct sockaddr*)&local,sizeof(local)) < 0)    {        perror("bind");        exit(3);    }    if(listen(sock, 10) < 0)    {        perror("listen");        exit(4);    }    return sock;}void *request(void *arg){    int new_sock = (int)arg;    while(1)    {         char buf[1024];         ssize_t s = read(new_sock, buf, sizeof(buf)-1);         if(s > 0)         {             buf[s] = 0;             printf("client# %s\n",buf);             write(new_sock, buf, strlen(buf));                }         else if(s == 0)         {             printf("client close!!\n");             break;         }         else         {             perror("read");             break;         }    }    close(new_sock);    return (void*)0;}//./tcp_server 192.18.X.X 8080int main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int listen_sock = startup(argv[1], atoi(argv[2]));    while(1)    {        struct sockaddr_in client;        socklen_t len = sizeof(client);        int new_sock = accept(listen_sock,(struct sockaddr*)&client, &len);        if(new_sock < 0)        {            perror("accept");            continue;        }        printf("get new client [%s:%d]\n",\                inet_ntoa(client.sin_addr),\                ntohs(client.sin_port));        pthread_t id;        pthread_create(&id,NULL,request,(void*)new_sock);        pthread_detach(id);    }    return 0;}

tcp_client.c

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <fcntl.h>static void usage(const char *proc){       printf("Usage: %s [server_ip] [server_port]\n",proc);}//./tcp_client server_ip server_portint main(int argc, char *argv[]){    if(argc != 3)    {        usage(argv[0]);        return 1;    }    int sock = socket(AF_INET, SOCK_STREAM, 0);    if(sock < 0)    {        perror("socket");        return 2;    }    struct sockaddr_in server;    server.sin_family = AF_INET;    server.sin_port = htons(atoi(argv[2]));    server.sin_addr.s_addr = inet_addr(argv[1]);    if(connect(sock,(struct sockaddr*)&server,sizeof(server)) < 0)    {        perror("connect");        return 3;    }    char buf[1024];    while(1)    {        printf("Please Enter#");        fflush(stdout);        ssize_t s = read(0, buf, sizeof(buf) - 1);        if(s > 0)        {            buf[s-1]= 0;            write(sock, buf, strlen(buf));            ssize_t _s = read(sock, buf, sizeof(buf)-1);            if(_s > 0)            {                buf[_s] = 0;                printf("server echo# %s\n",buf);            }        }    }    close(sock);    return 0;}

进程池和线程池

进程池和线程池相似，所以这里我们以进程池为例进行介绍。如没有特殊声明，下面对进程池的描述也适用于线程池。

进程池是由服务器预先创建的一组子进程，这些子进程的数目在 3~10 个之间（当然这只是典型情况）。线程池中的线程数量应该和 CPU 数量差不多。

进程池中的所有子进程都运行着相同的代码，并具有相同的属性，比如优先级、 PGID 等。

当有新的任务来到时，主进程将通过某种方式选择进程池中的某一个子进程来为之服务。相比于动态创建子进程，选择一个已经存在的子进程的代价显得小得多。至于主进程选择哪个子进程来为新任务服务，则有两种方法：

1）主进程使用某种算法来主动选择子进程。最简单、最常用的算法是随机算法和 Round Robin （轮流算法）。

2）主进程和所有子进程通过一个共享的工作队列来同步，子进程都睡眠在该工作队列上。当有新的任务到来时，主进程将任务添加到工作队列中。这将唤醒正在等待任务的子进程，不过只有一个子进程将获得新任务的“接管权”，它可以从工作队列中取出任务并执行之，而其他子进程将继续睡眠在工作队列上。

当选择好子进程后，主进程还需要使用某种通知机制来告诉目标子进程有新任务需要处理，并传递必要的数据。最简单的方式是，在父进程和子进程之间预先建立好一条管道，然后通过管道来实现所有的进程间通信。在父线程和子线程之间传递数据就要简单得多，因为我们可以把这些数据定义为全局，那么它们本身就是被所有线程共享的。

线程池主要用于：

1）需要大量的线程来完成任务，且完成任务的时间比较短。 比如WEB服务器完成网页请求这样的任务，使用线程池技术是非常合适的。因为单个任务小，而任务数量巨大。但对于长时间的任务，比如一个Telnet连接请求，线程池的优点就不明显了。因为Telnet会话时间比线程的创建时间大多了。

2）对性能要求苛刻的应用，比如要求服务器迅速响应客户请求。

3）接受突发性的大量请求，但不至于使服务器因此产生大量线程的应用。