loop.c

unix环境高级编程的源代码

#include    "opend.h"
#include    <sys/time.h>

void
loop(void)
{
    int        i, n, maxfd, maxi, listenfd, clifd, nread;
    char    buf[MAXLINE];
    uid_t    uid;
    fd_set    rset, allset;

    FD_ZERO(&allset);

                /* obtain fd to listen for client requests on */
    if ( (listenfd = serv_listen(CS_OPEN)) < 0)
        log_sys("serv_listen error");
    FD_SET(listenfd, &allset);
    maxfd = listenfd;
    maxi = -1;

    for ( ; ; ) {
        rset = allset;        /* rset gets modified each time around */
        if ( (n = select(maxfd + 1, &rset, NULL, NULL, NULL)) < 0)
            log_sys("select error");

        if (FD_ISSET(listenfd, &rset)) {
                    /* accept new client request */
            if ( (clifd = serv_accept(listenfd, &uid)) < 0)
                log_sys("serv_accept error: %d", clifd);
            i = client_add(clifd, uid);
            FD_SET(clifd, &allset);
            if (clifd > maxfd)
                maxfd = clifd;    /* max fd for select() */
            if (i > maxi)
                maxi = i;        /* max index in client[] array */
            log_msg("new connection: uid %d, fd %d", uid, clifd);
            continue;
        }

        for (i = 0; i <= maxi; i++) {    /* go through client[] array */
            if ( (clifd = client[i].fd) < 0)
                continue;
            if (FD_ISSET(clifd, &rset)) {
                        /* read argument buffer from client */
                if ( (nread = read(clifd, buf, MAXLINE)) < 0)
                    log_sys("read error on fd %d", clifd);
                else if (nread == 0) {
                    log_msg("closed: uid %d, fd %d",
                                        client[i].uid, clifd);
                    client_del(clifd);    /* client has closed conn */
                    FD_CLR(clifd, &allset);
                    close(clifd);
                } else            /* process client's rquest */
                    request(buf, nread, clifd, client[i].uid);
            }
        }
    }
}