Linux信号处理统一事件源

来源：互联网发布：nginx重启编辑：程序博客网时间：2024/06/07 20:50
#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <assert.h>#include <stdio.h>#include <signal.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <fcntl.h>#include <stdlib.h>#include <sys/epoll.h>#include <pthread.h>#define MAX_EVENT_NUMBER 1024static int pipefd[2];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;}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 );}//信号处理函数void sig_handler( int sig ){    int save_errno = errno;    int msg = sig;    send( pipefd[1], ( char* )&msg, 1, 0 );    errno = save_errno;}//设置信号的处理函数void addsig( int sig ){    struct sigaction sa;    memset( &sa, '\0', sizeof( sa ) );    sa.sa_handler = sig_handler;    sa.sa_flags |= SA_RESTART;    sigfillset( &sa.sa_mask );    assert( sigaction( sig, &sa, NULL ) != -1 );}int main( int argc, char* argv[] ){    if( argc <= 2 )    {        printf( "usage: %s ip_address port_number\n", basename( argv[0] ) );        return 1;    }    const char* ip = argv[1];    int port = atoi( argv[2] );    int ret = 0;    struct sockaddr_in address;    bzero( &address, sizeof( address ) );    address.sin_family = AF_INET;    inet_pton( AF_INET, ip, &address.sin_addr );    address.sin_port = htons( port );    int listenfd = socket( PF_INET, SOCK_STREAM, 0 );    assert( listenfd >= 0 );    //int nReuseAddr = 1;    //setsockopt( listenfd, SOL_SOCKET, SO_REUSEADDR, &nReuseAddr, sizeof( nReuseAddr ) );    ret = bind( listenfd, ( struct sockaddr* )&address, sizeof( address ) );    if( ret == -1 )    {        printf( "errno is %d\n", errno );        return 1;    }    //assert( ret != -1 );    ret = listen( listenfd, 5 );    assert( ret != -1 );    epoll_event events[ MAX_EVENT_NUMBER ];    int epollfd = epoll_create( 5 );    assert( epollfd != -1 );    addfd( epollfd, listenfd );    //使用socketpair创建管道，注册pipefd[0]上的可读事件    ret = socketpair( PF_UNIX, SOCK_STREAM, 0, pipefd );    assert( ret != -1 );    setnonblocking( pipefd[1] );    addfd( epollfd, pipefd[0] );    //设置一些信号的处理函数    addsig( SIGHUP );    addsig( SIGCHLD );    addsig( SIGTERM );    addsig( SIGINT );    bool stop_server = false;    while( !stop_server )    {        int number = epoll_wait( 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;            //如果就绪的文件描述符时listenfd,则处理新的连接            if( sockfd == listenfd )            {                struct sockaddr_in client_address;                socklen_t client_addrlength = sizeof( client_address );                int connfd = accept( listenfd, ( struct sockaddr* )&client_address, &client_addrlength );                addfd( epollfd, connfd );            }            //如果就绪的文件描述符是pipefd[0]，则处理信号            else if( ( sockfd == pipefd[0] ) && ( events[i].events & EPOLLIN ) )            {                int sig;                char signals[1024];                ret = recv( pipefd[0], signals, sizeof( signals ), 0 );                if( ret == -1 )                {                    continue;                }                else if( ret == 0 )                {                    continue;                }                else                {                //因为每个信号值占1字节，所以按字节来逐个接收信号。我们以                //SIGTERM为例，来说明如何安全地终止服务器主循环                    for( int i = 0; i < ret; ++i )                    {                        //printf( "I caugh the signal %d\n", signals[i] );                        switch( signals[i] )                        {                            case SIGCHLD:                            case SIGHUP:                            {                                continue;                            }                            case SIGTERM:                            case SIGINT:                            {                                stop_server = true;                            }                        }                    }                }            }            else            {            }        }    }    printf( "close fds\n" );    close( listenfd );    close( pipefd[1] );    close( pipefd[0] );    return 0;}
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