cpp线程池模板

#ifndef PROCESSPOOL_H
#define PROCESSPOOL_H

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/epoll.h>
#include <signal.h>
#include <sys/wait.h>
#include <sys/stat.h>

class process {
public:
    process() : m_pid(-1) {}

public:
    pid_t m_pid;
    int m_pipefd[2]; // 父进程和子进程通信用管道
};

template <typename T> // 模板参数是处理逻辑任务的类
class processpool {
private:
    // 定义为私有，只能通过create静态函数来创建processpool实例
    processpool(int listenfd, int process_number = 8);

public:
    // 单例模式，是程序正确处理信号的必要条件
    static processpool<T> *create(int listenfd, int process_number = 8) {
        if (!m_instance) {
            m_instance = new processpool<T>(listenfd, process_number);
        }
        return m_instance;
    }
    ~processpool() {
        delete[] m_sub_process;
    }
    void run();

private:
    void setup_sig_pipe();
    void run_parent();
    void run_child();

private:
    static const int MAX_PROCESS_NUMBER = 16; // 最大子进程数量
    static const int USER_PER_PROCESS = 65536; // 每个子进程处理最大客户数量
    static const int MAX_EVENT_NUMBER = 10000; // epoll最多能处理的事件数
    int m_process_number; // 进程总数
    int m_idx; // 子进程在池中序号
    int m_epollfd; // 每个进程有个epoll内核事件表
    int m_listenfd; // 监听socket
    int m_stop; // 子进程通过m_stop判断是否停止运行
    process *m_sub_process; // 保存所有子进程描述信息
    static processpool<T> *m_instance; // 进程池静态实例
};
template <typename T>
processpool<T> *processpool<T>::m_instance = NULL;

static int sig_pipefd[2]; // 信号管道 统一事件源

static int setnonblocking(int fd) {
    int old_option = fcntl(fd, F_GETFL);
    int new_option = old_option | O_NONBLOCK;
    fcntl(fd, F_SETFL, new_option);
    return old_option;
}

static void addfd(int epollfd, int fd) {
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN | EPOLLET;
    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);
    setnonblocking(fd);
}

static void removefd(int epollfd, int fd) { // 从epollfd表示的内核事件表中删除fd的 所有事件
    epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, 0);
    close(fd);
}

static void sig_handler(int sig) {
    int save_errno = errno;
    int msg = sig;
    send(sig_pipefd[1], (char *)&msg, 1, 0);
    errno = save_errno;
}

static void addsig(int sig, void(handler)(int), bool restart = true) {
    struct sigaction sa;
    memset(&sa, '\0', sizeof(sa));
    sa.sa_handler = handler;
    if (restart)
    {
        sa.sa_flags |= SA_RESTART;
    }
    sigfillset(&sa.sa_mask);
    assert(sigaction(sig, &sa, NULL) != -1);
}

template <typename T>
processpool<T>::processpool(int listenfd, int process_number) // 进程池构造函数，参数listenfd是监听的socket，必须在创建进程池之前被创建
    : m_listenfd(listenfd), m_process_number(process_number), m_idx(-1), m_stop(false) {
    assert((process_number > 0) && (process_number <= MAX_PROCESS_NUMBER));

    m_sub_process = new process[process_number];
    assert(m_sub_process);

    for (int i = 0; i < process_number; ++i) {
        int ret = socketpair(PF_UNIX, SOCK_STREAM, 0, m_sub_process[i].m_pipefd);
        assert(ret == 0);

        m_sub_process[i].m_pid = fork();
        assert(m_sub_process[i].m_pid >= 0);
        if (m_sub_process[i].m_pid > 0) { // 父进程
            close(m_sub_process[i].m_pipefd[1]); // 只向子进程写
            continue;
        }
        else { // 子进程
            close(m_sub_process[i].m_pipefd[0]); // 只从父进程读
            m_idx = i;
            break;
        }
    }
}

template <typename T>
void processpool<T>::setup_sig_pipe() { // 统一事件源
    m_epollfd = epoll_create(5); // 创建epoll事件监听表和信号管道
    assert(m_epollfd != -1);

    int ret = socketpair(PF_UNIX, SOCK_STREAM, 0, sig_pipefd);
    assert(ret != -1);

    setnonblocking(sig_pipefd[1]);
    addfd(m_epollfd, sig_pipefd[0]);

    addsig(SIGCHLD, sig_handler); // 设置信号处理函数
    addsig(SIGTERM, sig_handler);
    addsig(SIGINT, sig_handler);
    addsig(SIGPIPE, SIG_IGN);
}

template <typename T>
void processpool<T>::run() { // 父进程中m_idx值为 -1， 子进程中m_idx值 >= 0，判断接下来运行的是父还是子进程的代码
    if (m_idx != -1)
    {
        run_child();
        return;
    }
    run_parent();
}

template <typename T>
void processpool<T>::run_child() {
    setup_sig_pipe();

    int pipefd = m_sub_process[m_idx].m_pipefd[1]; // 每个子进程都通过其在进程池中的序号值m_idx找到与父进程通信的管道
    addfd(m_epollfd, pipefd); // 子进程需要监听管道文件描述符pipefd 因为父进程将通过它通知子进程accept新连接

    epoll_event events[MAX_EVENT_NUMBER];
    T *users = new T[USER_PER_PROCESS];
    assert(users);
    int number = 0; // epoll事件数量
    int ret = -1;

    while (!m_stop) {
        number = epoll_wait(m_epollfd, events, MAX_EVENT_NUMBER, -1);
        if ((number < 0) && (errno != EINTR)) {
            printf("epoll failure\n");
            break;
        }

        for (int i = 0; i < number; i++) { // 处理每个事件
            int sockfd = events[i].data.fd;
            if ((sockfd == pipefd) && (events[i].events & EPOLLIN)) { // 父进程有数据给子进程
                int client = 0;
                ret = recv(sockfd, (char *)&client, sizeof(client), 0); // 从父子进程之间管道读取数据，结果保存client中读取成功有新客户
                if (((ret < 0) && (errno != EAGAIN)) || ret == 0) {
                    continue;
                } else {
                    struct sockaddr_in client_address;
                    socklen_t client_addrlength = sizeof(client_address);
                    int connfd = accept(m_listenfd, (struct sockaddr *)&client_address, &client_addrlength);
                    if (connfd < 0) {
                        printf("errno is: %d\n", errno);
                        continue;
                    }
                    addfd(m_epollfd, connfd); // 模板类T必须实现init方法，初始化一个客户连接。我们用connfd来索引处理的逻辑对象 提高效率
                    users[connfd].init(m_epollfd, connfd, client_address); // 实现在cgi_server.cpp中
                }
            } else if ((sockfd == sig_pipefd[0]) && (events[i].events & EPOLLIN)) { // 有信号，处理信号
                int sig;
                char signals[1024];
                ret = recv(sig_pipefd[0], signals, sizeof(signals), 0);
                if (ret <= 0) {
                    continue;
                } else {
                    for (int i = 0; i < ret; ++i) {
                        switch (signals[i]) {
                            case SIGCHLD: { // 回收子进程资源
                                pid_t pid;
                                int stat;
                                while ((pid = waitpid(-1, &stat, WNOHANG)) > 0) {
                                    continue;
                                }
                                break;
                            }
                            case SIGTERM:
                            case SIGINT: {
                                m_stop = true;
                                break;
                            }
                            default: {
                                break;
                            }
                        }
                    }
                }
            } else if (events[i].events & EPOLLIN) { // 其他数据可读 必然是客户请求到来 调用逻辑处理对象的process方法处理
                users[sockfd].process(); // 还没实现
            } else {
                continue;
            }
        }
    }

    delete[] users;
    users = NULL;
    close(pipefd);
    //close( m_listenfd ); // 应该由m_listenfd的创建者来关闭，所谓的对象由哪个函数创建，就该由那个函数销毁
    close(m_epollfd);
}

template <typename T>
void processpool<T>::run_parent() {
    setup_sig_pipe();

    addfd(m_epollfd, m_listenfd);

    epoll_event events[MAX_EVENT_NUMBER];
    int sub_process_counter = 0;
    int new_conn = 1;
    int number = 0;
    int ret = -1;

    while (!m_stop) {
        number = epoll_wait(m_epollfd, events, MAX_EVENT_NUMBER, -1);
        if ((number < 0) && (errno != EINTR)) {
            printf("epoll failure\n");
            break;
        }

        for (int i = 0; i < number; i++) {
            int sockfd = events[i].data.fd;
            if (sockfd == m_listenfd) {
                int i = sub_process_counter; // 有新连接到来，就采用round robin方式将其分给一个子进程
                do {
                    if (m_sub_process[i].m_pid != -1) { // 选出空闲进程的进程数组索引
                        break;
                    }
                    i = (i + 1) % m_process_number;
                } while (i != sub_process_counter);

                if (m_sub_process[i].m_pid == -1) {
                    m_stop = true;
                    break;
                }
                sub_process_counter = (i + 1) % m_process_number;
                //send( m_sub_process[sub_process_counter++].m_pipefd[0], ( char* )&new_conn, sizeof( new_conn ), 0 );
                send(m_sub_process[i].m_pipefd[0], (char *)&new_conn, sizeof(new_conn), 0);
                printf("send request to child %d\n", i);
                //sub_process_counter %= m_process_number;
            } else if ((sockfd == sig_pipefd[0]) && (events[i].events & EPOLLIN)) { // 处理父进程收到的信号
                int sig;
                char signals[1024];
                ret = recv(sig_pipefd[0], signals, sizeof(signals), 0);
                if (ret <= 0) {
                    continue;
                } else {
                    for (int i = 0; i < ret; ++i) {
                        switch (signals[i]) {
                            case SIGCHLD: {
                                pid_t pid;
                                int stat;
                                while ((pid = waitpid(-1, &stat, WNOHANG)) > 0) {
                                    for (int i = 0; i < m_process_number; ++i) {
                                        // 如果进程池中第i个子进程退出了，则主进程关闭对应通信管道，并设置m_pid为-1，标记子进程已经退出
                                        if (m_sub_process[i].m_pid == pid) {
                                            printf("child %d join\n", i);
                                            close(m_sub_process[i].m_pipefd[0]);
                                            m_sub_process[i].m_pid = -1;
                                        }
                                    }
                                }
                                m_stop = true;
                                for (int i = 0; i < m_process_number; ++i) {
                                    if (m_sub_process[i].m_pid != -1) {
                                        m_stop = false;
                                    }
                                }
                                break;
                            }
                            case SIGTERM:
                            case SIGINT: {
                                printf("kill all the clild now\n"); // 杀了所有子进程
                                for (int i = 0; i < m_process_number; ++i) {
                                    int pid = m_sub_process[i].m_pid;
                                    if (pid != -1) {
                                        kill(pid, SIGTERM);
                                    }
                                }
                                break;
                            }
                            default: {
                                break;
                            }
                        }
                    }
                }
            } else {
                continue;
            }
        }
    }

    //close( m_listenfd ); // 由创建者关闭  见后文
    close(m_epollfd);
}

#endif

此头文件需要传入cgi模板类以进行实例化线程池。模板代码见下一节。

---

reference:
linux高性能服务器编程——游双