[linux系统编程]网络编程 服务器多路复用

作为一个命令台使用的服务器：

#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <memory.h>#include <math.h>#include <errno.h>#include <fcntl.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/ipc.h> #include <sys/msg.h>#include <pthread.h>#include <signal.h>#include <time.h>#include <sys/time.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define PORT 10000#define LISTEN_NUM      10#define MAX_PACKET_SIZE(1024)static int connect_fd[LISTEN_NUM];int main(){int sPort = PORT;    int sListen = 0;    int sAccept = 0;    unsigned int sLen = 0;    int sReuseaddr = 1;    int sSocketopt = 0;    struct sockaddr_in ser;    struct sockaddr_in cli;    int ret = -1;    int iloop = 0;    int kloop = 0;    int jloop = 0;    int count_id = 0;        char buf[MAX_PACKET_SIZE] = {0};    fd_set fdsr;    int max_sock;    struct timeval timeout;    sLen = sizeof(cli);    max_sock = sListen;        sListen = socket(AF_INET, SOCK_STREAM, 0);    if(sListen < 0)    {        printf("cmd_server socket() failure!\n");        return (-1);    }        sSocketopt = setsockopt(sListen, SOL_SOCKET, SO_REUSEADDR, &sReuseaddr, sizeof(int));    if(sSocketopt < 0)    {        printf("cmd_server setsockopt() failure!\n");        return (-1);    }        ser.sin_family = AF_INET;    ser.sin_port = htons(sPort);    ser.sin_addr.s_addr = htonl(INADDR_ANY);    memset(ser.sin_zero, '\0', sizeof(ser.sin_zero));        if(bind(sListen, (struct sockaddr*)&ser, sizeof(ser)) < 0)    {        printf("cmd_server bind() failure!\n");        return (-1);    }        if(listen(sListen, LISTEN_NUM) < 0)    {        printf("cmd_server listen() failure!\n");        return (-1);    }sLen = sizeof(cli);    max_sock = sListen;    for (iloop = 0; iloop < LISTEN_NUM; iloop++)    {          connect_fd[iloop] = 0;              }        for(;;)    {    timeout.tv_sec  = 3;    timeout.tv_usec = 0;        FD_ZERO(&fdsr);        FD_SET(sListen, &fdsr);                for (iloop = 0; iloop < LISTEN_NUM; iloop++)        {            if (connect_fd[iloop] != 0)            {                FD_SET(connect_fd[iloop], &fdsr);            }        }                ret = select(max_sock + 1, &fdsr, NULL, NULL, &timeout);        if (ret == 0)        {        printf("SERVER select time out\n");            continue;        }        else if (ret < 0)        {printf("SERVER select failured\n");            continue;        }                for (kloop = 0; kloop < LISTEN_NUM; kloop++)        {            if (FD_ISSET(connect_fd[kloop], &fdsr))            {            memset(buf, 0x00, sizeof(buf));            ret = recv(connect_fd[kloop], &buf, sizeof(buf), 0);if(ret <= 0){printf("Close socket\n");close(connect_fd[kloop]);FD_CLR(connect_fd[kloop], &fdsr);connect_fd[kloop] = 0;}else{//处理程序}}        }                if (FD_ISSET(sListen, &fdsr)){sAccept = accept(sListen, (struct sockaddr *)&cli, (unsigned int*)&sLen);if (sAccept <= 0){printf("cmd_server accept() failure!  errno=%d, slisten=%d\n",errno,sListen);usleep(5000);continue;}for(count_id = 0; count_id < LISTEN_NUM; count_id++)  {if(connect_fd[count_id] == 0){break;}}if (count_id == LISTEN_NUM)  {printf("max connections arrive, exit!!!\n");for (jloop = 0; jloop < LISTEN_NUM; jloop++){if (connect_fd[jloop] != 0){connect_fd[jloop] = 0;FD_CLR(connect_fd[jloop], &fdsr);close(connect_fd[jloop]);}}usleep(5000);continue;}if (sAccept > max_sock){max_sock = sAccept;}connect_fd[count_id] = sAccept;printf("Accept OK!  count_id=%d\n", count_id);}}return 0;}