path: root/mbbsd/mbbsd.c

/* $Id$ */
#define TELOPTS
#define TELCMDS
#include "bbs.h"

#ifdef __linux__
#    ifdef CRITICAL_MEMORY
#        include <malloc.h>
#    endif
#    ifdef DEBUG
#        include <mcheck.h>
#    endif
#endif


#define SOCKET_QLEN 4

static void do_aloha(const char *hello);
static void getremotename(const struct sockaddr_in * from, char *rhost, char *rname);

#ifdef CONVERT
void big2gb_init(void*);
void gb2big_init(void*);
void big2uni_init(void*);
void uni2big_init(void*);
#endif

#if 0
static jmp_buf  byebye;
#endif

static char     remoteusername[40] = "?";

static unsigned char enter_uflag;
static int      use_shell_login_mode = 0;

#ifdef USE_RFORK
#define fork() rfork(RFFDG | RFPROC | RFNOWAIT)
#endif

/* set signal handler, which won't be reset once signal comes */
static void
signal_restart(int signum, void (*handler) (int))
{
    struct sigaction act;
    act.sa_handler = handler;
    memset(&(act.sa_mask), 0, sizeof(sigset_t));
    act.sa_flags = 0;
    sigaction(signum, &act, NULL);
}

static void
start_daemon(void)
{
    int             n, fd;

    /*
     * More idiot speed-hacking --- the first time conversion makes the C
     * library open the files containing the locale definition and time zone.
     * If this hasn't happened in the parent process, it happens in the
     * children, once per connection --- and it does add up.
     */
    time_t          dummy = time(NULL);
    struct tm      *dummy_time = localtime(&dummy);
    char            buf[32];

    strftime(buf, sizeof(buf), "%d/%b/%Y:%H:%M:%S", dummy_time);

#ifndef NO_FORK
    if ((n = fork())) {
    exit(0);
    }
#endif

    /* rocker.011018: it's a good idea to close all unexcept fd!! */
#ifndef VALGRIND
    n = getdtablesize();
    while (n)
    close(--n);

    /* in2: open /dev/null to fd:2 */
    if( ((fd = open("/dev/null", O_WRONLY)) >= 0) && fd != 2 ){
    dup2(fd, 2);
    close(fd);
    }
#endif

    if(getenv("SSH_CLIENT"))
    unsetenv("SSH_CLIENT");

    /*
     * rocker.011018: we don't need to remember original tty, so request a
     * new session id
     */
    setsid();

    /*
     * rocker.011018: after new session, we should insure the process is
     * clean daemon
     */
#ifndef NO_FORK
    if ((n = fork())) {
    exit(0);
    }
#endif
}

static void
reapchild(int sig)
{
    int             state, pid;

    while ((pid = waitpid(-1, &state, WNOHANG | WUNTRACED)) > 0);
}

void
log_usies(const char *mode, const char *mesg)
{

    if (!mesg)
        log_file(FN_USIES, LOG_CREAT | LOG_VF, 
                 "%s %s %-12s Stay:%d (%s)\n",
                 Cdate(&now), mode, cuser.userid ,
                 (int)(now - login_start_time) / 60, cuser.nickname);
    else
        log_file(FN_USIES, LOG_CREAT | LOG_VF,
                 "%s %s %-12s %s\n",
                 Cdate(&now), mode, cuser.userid, mesg);

    /* 追蹤使用者 */
    if (HasUserPerm(PERM_LOGUSER))
        log_user("logout");
}


static void
setflags(int mask, int value)
{
    if (value)
    cuser.uflag |= mask;
    else
    cuser.uflag &= ~mask;
}

void
u_exit(const char *mode)
{
    int diff = (time(0) - login_start_time) / 60;
    int dirty = currmode & MODE_DIRTY;

    currmode = 0;

    /* close fd 0 & 1 to terminate network */
    close(0);
    close(1);

    assert(strncmp(currutmp->userid,cuser.userid, IDLEN)==0);
    if(strncmp(currutmp->userid,cuser.userid, IDLEN)!=0)
    return;

    reload_money();
    cuser.goodpost = currutmp->goodpost;
    cuser.badpost = currutmp->badpost;
    cuser.goodsale = currutmp->goodsale;
    cuser.badsale = currutmp->badsale;

    auto_backup();
    setflags(PAGER_FLAG, currutmp->pager != PAGER_ON);
    setflags(CLOAK_FLAG, currutmp->invisible);
    save_brdbuf();
    brc_finalize();

    cuser.invisible = currutmp->invisible;
    cuser.withme = currutmp->withme;
    cuser.pager = currutmp->pager;
    memcpy(cuser.mind, currutmp->mind, 4);
    setutmpbid(0);
    if (!(HasUserPerm(PERM_SYSOP) && HasUserPerm(PERM_SYSOPHIDE)) &&
    !currutmp->invisible)
    do_aloha("<<下站通知>> -- 我走囉！");

    purge_utmp(currutmp);
    if ((cuser.uflag != enter_uflag) || dirty || diff) {
    if (!diff && cuser.numlogins)
        cuser.numlogins = --cuser.numlogins;
    /* Leeym 上站停留時間限制式 */
    }
    passwd_update(usernum, &cuser);
    log_usies(mode, NULL);
}

void
abort_bbs(int sig)
{
    if (currmode)
    u_exit("ABORTED");
    exit(0);
}

#ifdef GCC_NORETURN
static void abort_bbs_debug(int sig) GCC_NORETURN;
#endif

/* NOTE: It's better to use signal-safe functions. Avoid to call
 * functions with global/static variable -- data may be corrupted */
static void
abort_bbs_debug(int sig)
{
    int    i;
    sigset_t sigset;

    switch(sig) {
      case SIGINT: STATINC(STAT_SIGINT); break;
      case SIGQUIT: STATINC(STAT_SIGQUIT); break;
      case SIGILL: STATINC(STAT_SIGILL); break;
      case SIGABRT: STATINC(STAT_SIGABRT); break;
      case SIGFPE: STATINC(STAT_SIGFPE); break;
      case SIGBUS: STATINC(STAT_SIGBUS); break;
      case SIGSEGV: STATINC(STAT_SIGSEGV); break;
      case SIGXCPU: STATINC(STAT_SIGXCPU); break;
    }
    /* ignore normal signals */
    Signal(SIGALRM, SIG_IGN);
    Signal(SIGUSR1, SIG_IGN);
    Signal(SIGUSR2, SIG_IGN);
    Signal(SIGHUP, SIG_IGN);
    Signal(SIGTERM, SIG_IGN);
    Signal(SIGPIPE, SIG_IGN);

    /* unblock */
    sigemptyset(&sigset);
    sigaddset(&sigset, SIGINT);
    sigaddset(&sigset, SIGQUIT);
    sigaddset(&sigset, SIGILL);
    sigaddset(&sigset, SIGABRT);
    sigaddset(&sigset, SIGFPE);
    sigaddset(&sigset, SIGBUS);
    sigaddset(&sigset, SIGSEGV);
    sigaddset(&sigset, SIGXCPU);
    sigprocmask(SIG_UNBLOCK, &sigset, NULL);

#define CRASH_MSG ANSI_COLOR(0) "\r\n程式異常, 立刻斷線. 請洽 PttBug 板詳述你發生的問題.\n"
    write(1, CRASH_MSG, sizeof(CRASH_MSG));

    /* close all file descriptors (including the network connection) */
    for (i = 0; i < 256; ++i)
    close(i);

    /* log */
    /* assume vsnprintf() in log_file() is signal-safe, is it? */
    log_file("log/crash.log", LOG_VF|LOG_CREAT, 
        "%ld %d\n", time4(NULL), getpid());

    /* try logout... not a good idea, maybe crash again. now disabled */
    /*
    if (currmode) {
    currmode = 0;
    u_exit("AXXED");
    }
    */

#ifdef DEBUGSLEEP

#ifndef VALGRIND
    setproctitle("debug me!(%d)(%s,%d)", sig, cuser.userid, currstat);
#endif
    /* do this manually to prevent broken stuff */
    /* will broken currutmp cause problems here? hope not... */
    if(currutmp && strncmp(cuser.userid, currutmp->userid, IDLEN) == EQUSTR)
    currutmp->mode = DEBUGSLEEPING;

    sleep(3600);        /* wait 60 mins for debug */
#endif

    exit(0);
}

/* 登錄 BBS 程式 */
static void
mysrand(void)
{
    srandom(time(NULL) + getpid()); /* 時間跟 pid 當 rand 的 seed */
}

void
talk_request(int sig)
{
    STATINC(STAT_TALKREQUEST);
    bell();
    bell();
    if (currutmp->msgcount) {
    char            timebuf[100];
    time4_t          now = time(0);

    move(0, 0);
    clrtoeol();
    prints(ANSI_COLOR(33;41) "★%s" ANSI_COLOR(34;47) " [%s] %s " ANSI_COLOR(0) "",
         SHM->uinfo[currutmp->destuip].userid, my_ctime(&now,timebuf,sizeof(timebuf)),
         (currutmp->sig == 2) ? "重要消息廣播！(請Ctrl-U,l查看熱訊記錄)"
         : "呼叫、呼叫，聽到請回答");
    refresh();
    } else {
    unsigned char   mode0 = currutmp->mode;
    char            c0 = currutmp->chatid[0];
    screen_backup_t old_screen;

    currutmp->mode = 0;
    currutmp->chatid[0] = 1;
    screen_backup(&old_screen);
    talkreply();
    currutmp->mode = mode0;
    currutmp->chatid[0] = c0;
    screen_restore(&old_screen);
    }
}

void
show_call_in(int save, int which)
{
    char            buf[200];
#ifdef PLAY_ANGEL
    if (currutmp->msgs[which].msgmode == MSGMODE_TOANGEL)
    snprintf(buf, sizeof(buf), ANSI_COLOR(1;37;46) "★%s" ANSI_COLOR(37;45) " %s " ANSI_RESET,
        currutmp->msgs[which].userid, currutmp->msgs[which].last_call_in);
    else
#endif
    snprintf(buf, sizeof(buf), ANSI_COLOR(1;33;46) "★%s" ANSI_COLOR(37;45) " %s " ANSI_RESET,
         currutmp->msgs[which].userid, currutmp->msgs[which].last_call_in);
    outmsg(buf);

    if (save) {
    char            genbuf[200];
    if (!fp_writelog) {
        sethomefile(genbuf, cuser.userid, fn_writelog);
        fp_writelog = fopen(genbuf, "a");
    }
    if (fp_writelog) {
        fprintf(fp_writelog, "%s [%s]\n", buf, Cdatelite(&now));
    }
    }
}

static int
add_history_water(water_t * w, const msgque_t * msg)
{
    memcpy(&w->msg[w->top], msg, sizeof(msgque_t));
    w->top++;
    w->top %= WATERMODE(WATER_OFO) ? 5 : MAX_REVIEW;

    if (w->count < MAX_REVIEW)
    w->count++;

    return w->count;
}

static int
add_history(const msgque_t * msg)
{
    int             i = 0, j, waterinit = 0;
    water_t        *tmp;
    if (WATERMODE(WATER_ORIG) || WATERMODE(WATER_NEW))
    add_history_water(&water[0], msg);
    if (WATERMODE(WATER_NEW) || WATERMODE(WATER_OFO)) {
    for (i = 0; i < 5 && swater[i]; i++)
        if (swater[i]->pid == msg->pid
#ifdef PLAY_ANGEL
            && swater[i]->msg[0].msgmode == msg->msgmode
            /* When throwing waterball to angel directly */
#endif
            )
        break;
    if (i == 5) {
        waterinit = 1;
        i = 4;
        memset(swater[4], 0, sizeof(water_t));
    } else if (!swater[i]) {
        water_usies = i + 1;
        swater[i] = &water[i + 1];
        waterinit = 1;
    }
    tmp = swater[i];

    if (waterinit) {
        memcpy(swater[i]->userid, msg->userid, sizeof(swater[i]->userid));
        swater[i]->pid = msg->pid;
    }
    if (!swater[i]->uin)
        swater[i]->uin = currutmp;

    for (j = i; j > 0; j--)
        swater[j] = swater[j - 1];
    swater[0] = tmp;
    add_history_water(swater[0], msg);
    }
    if (WATERMODE(WATER_ORIG) || WATERMODE(WATER_NEW)) {
    if (watermode > 0 &&
        (water_which == swater[0] || water_which == &water[0])) {
        if (watermode < water_which->count)
        watermode++;
        t_display_new();
    }
    }
    return i;
}

void
write_request(int sig)
{
    int             i, msgcount;

    STATINC(STAT_WRITEREQUEST);
#ifdef NOKILLWATERBALL
    if( reentrant_write_request ) /* kill again by shmctl */
    return;
    reentrant_write_request = 1;
#endif
    if (WATERMODE(WATER_OFO)) {
    /* 如果目前正在回水球模式的話, 就不能進行 add_history() ,
       因為會改寫 water[], 而使回水球目的爛掉, 所以分成幾種情況考慮.
       sig != 0表真的有水球進來, 故顯示.
       sig == 0表示沒有水球進來, 不過之前尚有水球還沒寫到 water[].
    */
    static  int     alreadyshow = 0;

    if( sig ){ /* 真的有水球進來 */

        /* 若原來正在 REPLYING , 則改成 RECVINREPLYING,
           這樣在回水球結束後, 會再呼叫一次 write_request(0) */
        if( wmofo == REPLYING )
        wmofo = RECVINREPLYING;

        /* 顯示 */
        for( ; alreadyshow < currutmp->msgcount && alreadyshow < MAX_MSGS
             ; ++alreadyshow ){
        bell();
        show_call_in(1, alreadyshow);
        refresh();
        }
    }

    /* 看看是不是要把 currutmp->msg 拿回 water[] (by add_history())
       須要是不在回水球中 (NOTREPLYING) */
    if( wmofo == NOTREPLYING &&
        (msgcount = currutmp->msgcount) > 0 ){
        for( i = 0 ; i < msgcount ; ++i )
        add_history(&currutmp->msgs[i]);
        if( (currutmp->msgcount -= msgcount) < 0 )
        currutmp->msgcount = 0;
        alreadyshow = 0;
    }
    } else {
    if (currutmp->mode != 0 &&
        currutmp->pager != PAGER_OFF &&
        cuser.userlevel != 0 &&
        currutmp->msgcount != 0 &&
        currutmp->mode != TALK &&
        currutmp->mode != EDITING &&
        currutmp->mode != CHATING &&
        currutmp->mode != PAGE &&
        currutmp->mode != IDLE &&
        currutmp->mode != MAILALL && currutmp->mode != MONITOR) {
        char            c0 = currutmp->chatid[0];
        int             currstat0 = currstat;
        unsigned char   mode0 = currutmp->mode;

        currutmp->mode = 0;
        currutmp->chatid[0] = 2;
        currstat = HIT;

#ifdef NOKILLWATERBALL
        currutmp->wbtime = 0;
#endif
        if( (msgcount = currutmp->msgcount) > 0 ){
        for( i = 0 ; i < msgcount ; ++i ){
            bell();
            show_call_in(1, 0);
            add_history(&currutmp->msgs[0]);

            if( (--currutmp->msgcount) < 0 )
            i = msgcount; /* force to exit for() */
            else if( currutmp->msgcount > 0 )
            memmove(&currutmp->msgs[0],
                &currutmp->msgs[1],
                sizeof(msgque_t) * currutmp->msgcount);
            igetch();
        }
        }

        currutmp->chatid[0] = c0;
        currutmp->mode = mode0;
        currstat = currstat0;
    } else {
        bell();
        show_call_in(1, 0);
        add_history(&currutmp->msgs[0]);

        refresh();
        currutmp->msgcount = 0;
    }
    }
#ifdef NOKILLWATERBALL
    reentrant_write_request = 0;
    currutmp->wbtime = 0; /* race */
#endif
}

static void
multi_user_check(void)
{
    register userinfo_t *ui;
    register pid_t  pid;
    char            genbuf[3];

    if (HasUserPerm(PERM_SYSOP))
    return;         /* don't check sysops */

    if (cuser.userlevel) {
    if (!(ui = (userinfo_t *) search_ulist(usernum)))
        return;     /* user isn't logged in */

#ifdef DEBUGSLEEP
    /* skip sleeping process */
    while (ui->pid &&
        (ui->uid == usernum && ui->mode == DEBUGSLEEPING))
        ui++;

    if(ui->uid != usernum)
        return;
#endif

    pid = ui->pid;
    if (!pid /* || (kill(pid, 0) == -1) */ )
        return;     /* stale entry in utmp file */

    getdata(b_lines - 1, 0, "您想刪除其他重複的 login (Y/N)嗎？[Y] ",
        genbuf, 3, LCECHO);

    if (genbuf[0] != 'n') {
        if (pid > 0)
        kill(pid, SIGHUP);
        log_usies("KICK ", cuser.nickname);
    } else {
        /* what are we doing here? magic number 3? */
        if (search_ulistn(usernum, 3) != NULL)
        abort_bbs(0);   /* Goodbye(); */
    }
    } else {
    /* allow multiple guest user */
    if (search_ulistn(usernum, 100) != NULL) {
        vmsg("抱歉，目前已有太多 guest 在站上, 請用new註冊。");
        exit(1);
    }
    }
}

/* bad login */
static char * const str_badlogin = "logins.bad";

static void
logattempt(const char *uid, char type)
{
    char            fname[40];
    int             fd, len;
    char            genbuf[200];

    snprintf(genbuf, sizeof(genbuf), "%c%-12s[%s] %s@%s\n", type, uid,
        Cdate(&login_start_time), remoteusername, fromhost);
    len = strlen(genbuf);
    if ((fd = open(str_badlogin, O_WRONLY | O_CREAT | O_APPEND, 0644)) > 0) {
    write(fd, genbuf, len);
    close(fd);
    }
    if (type == '-') {
    snprintf(genbuf, sizeof(genbuf),
         "[%s] %s\n", Cdate(&login_start_time), fromhost);
    len = strlen(genbuf);
    sethomefile(fname, uid, str_badlogin);
    if ((fd = open(fname, O_WRONLY | O_CREAT | O_APPEND, 0644)) > 0) {
        write(fd, genbuf, len);
        close(fd);
    }
    }
}

void mkuserdir(const char *userid)
{
    char genbuf[200];
    sethomepath(genbuf, userid);
    // assume it is a dir, so just check if it is exist
    if (access(genbuf, F_OK) != 0)
    mkdir(genbuf, 0755);
}

static void
login_query(void)
{
#ifdef CONVERT
    /* uid 加一位, for gb login */
    char            uid[IDLEN + 2], passbuf[PASSLEN];
    int             attempts, len;
#else
    char            uid[IDLEN + 1], passbuf[PASSLEN];
    int             attempts;
#endif
    resolve_garbage();
    now = time(0);

#ifdef DEBUG
    move(1, 0);
    prints("debugging mode\ncurrent pid: %d\n", getpid());
#else
    show_file("etc/Welcome", 1, -1, NO_RELOAD);
#endif
    output("1", 1);


    attempts = 0;
    while (1) {
    if (attempts++ >= LOGINATTEMPTS) {
        more("etc/goodbye", NA);
        pressanykey();
        exit(1);
    }
    bzero(&cuser, sizeof(cuser));
#ifdef DEBUG
    move(19, 0);
    prints("current pid: %d ", getpid());
#endif
    getdata(20, 0, "請輸入代號，或以[guest]參觀，以[new]註冊：",
        uid, sizeof(uid), DOECHO);
#ifdef CONVERT
    /* switch to gb mode if uid end with '.' */
    len = strlen(uid);
    if (uid[0] && uid[len - 1] == '.') {
        set_converting_type(CONV_GB);
        uid[len - 1] = 0;
    }
    else if (uid[0] && uid[len - 1] == ',') {
        set_converting_type(CONV_UTF8);
        uid[len - 1] = 0;
    }
    else if (len >= IDLEN + 1)
        uid[IDLEN] = 0;
#endif

    if (strcasecmp(uid, str_new) == 0) {
#ifdef LOGINASNEW
        new_register();
        mkuserdir(cuser.userid);
        break;
#else
        outs("本系統目前無法以 new 註冊, 請用 guest 進入\n");
        continue;
#endif
    } else if (uid[0] == '\0') {

        outs(err_uid);

    } else if (strcasecmp(uid, STR_GUEST) == 0) {   /* guest */

            if (initcuser(uid)< 1) exit (0) ;
        cuser.userlevel = 0;
        cuser.uflag = PAGER_FLAG | BRDSORT_FLAG | MOVIE_FLAG;
        mkuserdir(cuser.userid);
        break;

    } else {

        /* normal user */
        getdata(21, 0, MSG_PASSWD,
            passbuf, sizeof(passbuf), NOECHO);
        passbuf[8] = '\0';

        move (22, 0); clrtoeol();
        outs("正在檢查密碼...");
        move(22, 0); refresh(); 
        /* prepare for later */
        clrtoeol();

        if( initcuser(uid) < 1 || !cuser.userid[0] ||
        !checkpasswd(cuser.passwd, passbuf) ){

        logattempt(cuser.userid , '-');
        outs(ERR_PASSWD);

        } else {

        logattempt(cuser.userid, ' ');
        outs("密碼正確！ 開始登入系統..."); 
        move(22, 0); refresh();
        clrtoeol();

        if (strcasecmp(str_sysop, cuser.userid) == 0){
#ifdef NO_SYSOP_ACCOUNT
            exit(0);
#else /* 自動加上各個主要權限 */
            cuser.userlevel = PERM_BASIC | PERM_CHAT | PERM_PAGE |
            PERM_POST | PERM_LOGINOK | PERM_MAILLIMIT |
            PERM_CLOAK | PERM_SEECLOAK | PERM_XEMPT |
            PERM_SYSOPHIDE | PERM_BM | PERM_ACCOUNTS |
            PERM_CHATROOM | PERM_BOARD | PERM_SYSOP | PERM_BBSADM;
            mkuserdir(cuser.userid);
#endif
        }
        break;
        }
    }
    }
    multi_user_check();
}

void
add_distinct(const char *fname, const char *line)
{
    FILE           *fp;
    int             n = 0;

    if ((fp = fopen(fname, "a+"))) {
    char            buffer[80];
    char            tmpname[100];
    FILE           *fptmp;

    strlcpy(tmpname, fname, sizeof(tmpname));
    strcat(tmpname, "_tmp");
    if (!(fptmp = fopen(tmpname, "w"))) {
        fclose(fp);
        return;
    }
    rewind(fp);
    while (fgets(buffer, 80, fp)) {
        char           *p = buffer + strlen(buffer) - 1;

        if (p[-1] == '\n' || p[-1] == '\r')
        p[-1] = 0;
        if (!strcmp(buffer, line))
        break;
        sscanf(buffer + strlen(buffer) + 2, "%d", &n);
        fprintf(fptmp, "%s%c#%d\n", buffer, 0, n);
    }

    if (feof(fp))
        fprintf(fptmp, "%s%c#1\n", line, 0);
    else {
        sscanf(buffer + strlen(buffer) + 2, "%d", &n);
        fprintf(fptmp, "%s%c#%d\n", buffer, 0, n + 1);
        while (fgets(buffer, 80, fp)) {
        sscanf(buffer + strlen(buffer) + 2, "%d", &n);
        fprintf(fptmp, "%s%c#%d\n", buffer, 0, n);
        }
    }
    fclose(fp);
    fclose(fptmp);
    unlink(fname);
    rename(tmpname, fname);
    }
}

void
del_distinct(const char *fname, const char *line, int casesensitive)
{
    FILE           *fp;
    int             n = 0;

    if ((fp = fopen(fname, "r"))) {
    char            buffer[80];
    char            tmpname[100];
    FILE           *fptmp;

    strlcpy(tmpname, fname, sizeof(tmpname));
    strcat(tmpname, "_tmp");
    if (!(fptmp = fopen(tmpname, "w"))) {
        fclose(fp);
        return;
    }
    rewind(fp);
    while (fgets(buffer, 80, fp)) {
        char           *p = buffer + strlen(buffer) - 1;

        if (p[-1] == '\n' || p[-1] == '\r')
        p[-1] = 0;
        if(casesensitive)
        {
        if (!strcmp(buffer, line))
            break;
        } else {
        if (!strcasecmp(buffer, line))
            break;
        }
        sscanf(buffer + strlen(buffer) + 2, "%d", &n);
        fprintf(fptmp, "%s%c#%d\n", buffer, 0, n);
    }

    if (!feof(fp))
        while (fgets(buffer, 80, fp)) {
        sscanf(buffer + strlen(buffer) + 2, "%d", &n);
        fprintf(fptmp, "%s%c#%d\n", buffer, 0, n);
        }
    fclose(fp);
    fclose(fptmp);
    unlink(fname);
    rename(tmpname, fname);
    }
}

#ifdef WHERE
static int
where(const char *from)
{
    int i;

    for (i = 0; i < SHM->home_num; i++) {
    if ((SHM->home_ip[i] & SHM->home_mask[i]) == (ipstr2int(from) & SHM->home_mask[i])) {
        return i;
    }
    }
    return 0;
}
#endif

static void
check_BM(void)
{
    /* XXX: -_- */
    int             i;

    cuser.userlevel &= ~PERM_BM;
    for( i = 0 ; i < numboards ; ++i )
    if( is_BM_cache(i + 1) ) /* XXXbid */
        return;
    //for (i = 0, bhdr = bcache; i < numboards && !is_BM(bhdr->BM); i++, bhdr++);
}

static void
setup_utmp(int mode)
{
    userinfo_t      uinfo;
    memset(&uinfo, 0, sizeof(uinfo));
    uinfo.pid = currpid = getpid();
    uinfo.uid = usernum;
    uinfo.mode = currstat = mode;
    uinfo.mailalert = load_mailalert(cuser.userid);

    uinfo.userlevel = cuser.userlevel;
    uinfo.sex = cuser.sex % 8;
    uinfo.lastact = time(NULL);
    strlcpy(uinfo.userid, cuser.userid, sizeof(uinfo.userid));
    //strlcpy(uinfo.realname, cuser.realname, sizeof(uinfo.realname));
    strlcpy(uinfo.nickname, cuser.nickname, sizeof(uinfo.nickname));
    strip_nonebig5((unsigned char *)uinfo.nickname, sizeof(uinfo.nickname));
    strlcpy(uinfo.from, fromhost, sizeof(uinfo.from));
    uinfo.five_win = cuser.five_win;
    uinfo.five_lose = cuser.five_lose;
    uinfo.five_tie = cuser.five_tie;
    uinfo.chc_win = cuser.chc_win;
    uinfo.chc_lose = cuser.chc_lose;
    uinfo.chc_tie = cuser.chc_tie;
    uinfo.chess_elo_rating = cuser.chess_elo_rating;
    uinfo.invisible = cuser.invisible % 2;
    uinfo.pager = cuser.pager % PAGER_MODES;
    uinfo.goodpost = cuser.goodpost;
    uinfo.badpost = cuser.badpost;
    uinfo.goodsale = cuser.goodsale;
    uinfo.badsale = cuser.badsale;
    if(cuser.withme & (cuser.withme<<1) & (WITHME_ALLFLAG<<1))
    cuser.withme = 0;
    uinfo.withme = cuser.withme;
    memcpy(uinfo.mind, cuser.mind, 4);
    strip_nonebig5((unsigned char *)uinfo.mind, 4);
#ifdef WHERE
    uinfo.from_alias = where(fromhost);
#endif
#ifndef FAST_LOGIN
    setuserfile(buf, "remoteuser");

    strlcpy(remotebuf, fromhost, sizeof(fromhost));
    strcat(remotebuf, ctime4(&now));
    chomp(remotebuf);
    add_distinct(buf, remotebuf);
#endif
    if (enter_uflag & CLOAK_FLAG)
    uinfo.invisible = YEA;

#ifdef PLAY_ANGEL
    if (REJECT_QUESTION)
    uinfo.angel = 1;
    uinfo.angel |= ANGEL_STATUS() << 1;
#endif

    getnewutmpent(&uinfo);
    SHM->UTMPneedsort = 1;
    // XXX 不用每 20 才檢查吧
    if (!(cuser.numlogins % 20) && cuser.userlevel & PERM_BM)
    check_BM();     /* Ptt 自動取下離職板主權力 */

#ifndef _BBS_UTIL_C_
    /* Very, very slow friend_load. */
    if( strcmp(cuser.userid, STR_GUEST) != 0 ) // guest 不處理好友
    friend_load(0);
    nice(3);
#endif
}

inline static void welcome_msg(void)
{
    prints(ANSI_RESET "      歡迎您第 " 
        ANSI_COLOR(1;33) "%d" ANSI_COLOR(0;37) " 度拜訪本站，上次您是從 " 
        ANSI_COLOR(1;33) "%s" ANSI_COLOR(0;37) " 連往本站，" 
        ANSI_CLRTOEND "\n"
        "     我記得那天是 " ANSI_COLOR(1;33) "%s" ANSI_COLOR(0;37) "。"
        ANSI_CLRTOEND "\n"
        ANSI_CLRTOEND "\n"
        ,
        ++cuser.numlogins, cuser.lasthost, Cdate(&(cuser.lastlogin)));
    pressanykey();
}

inline static void check_bad_login(void)
{
    char            genbuf[200];
    setuserfile(genbuf, str_badlogin);
    if (more(genbuf, NA) != -1) {
    move(b_lines - 3, 0);
    outs("通常並沒有辦法知道該ip是誰所有, "
        "以及其意圖(是不小心按錯或有意測您密碼)\n"
        "若您有帳號被盜用疑慮, 請經常更改您的密碼或使用加密連線");
    if (getans("您要刪除以上錯誤嘗試的記錄嗎(Y/N)?[N]") == 'y')
        unlink(genbuf);
    }
}

inline static void birthday_make_a_wish(const struct tm *ptime, const struct tm *tmp)
{
    if (tmp->tm_mday != ptime->tm_mday) {
    more("etc/birth.post", YEA);
    brc_initial_board("WhoAmI");
    set_board();
    do_post();
    }
}

inline static void record_lasthost(const char *fromhost)
{
    strlcpy(cuser.lasthost, fromhost, sizeof(cuser.lasthost));
}

inline static void check_mailbox_quota(void)
{
    if (chkmailbox())
    m_read();
}

static void init_guest_info(void)
{
    int i;
    char           *nick[13] = {
    "椰子", "貝殼", "內衣", "寶特瓶", "翻車魚",
    "樹葉", "浮萍", "鞋子", "潛水艇", "魔王",
    "鐵罐", "考卷", "大美女"
    };
    char           *name[13] = {
    "大王椰子", "鸚鵡螺", "比基尼", "可口可樂", "仰泳的魚",
    "憶", "高岡屋", "AIR Jordon", "紅色十月號", "批踢踢",
    "SASAYA椰奶", "鴨蛋", "布魯克鱈魚香絲"
    };
    char           *addr[13] = {
    "天堂樂園", "大海", "綠島小夜曲", "美國", "綠色珊瑚礁",
    "遠方", "原本海", "NIKE", "蘇聯", "男八618室",
    "愛之味", "天上", "藍色珊瑚礁"
    };
    i = login_start_time % 13;
    snprintf(cuser.nickname, sizeof(cuser.nickname),
        "海邊漂來的%s", nick[(int)i]);
    strlcpy(currutmp->nickname, cuser.nickname,
        sizeof(currutmp->nickname));
    strlcpy(cuser.realname, name[(int)i], sizeof(cuser.realname));
    strlcpy(cuser.address, addr[(int)i], sizeof(cuser.address));
    cuser.sex = i % 8;
    currutmp->pager = PAGER_DISABLE;
}

#if FOREIGN_REG_DAY > 0
inline static void foreign_warning(void){
    if ((cuser.uflag2 & FOREIGN) && !(cuser.uflag2 & LIVERIGHT)){
    if (login_start_time - cuser.firstlogin > (FOREIGN_REG_DAY - 5) * 24 * 3600){
        mail_muser(cuser, "[出入境管理局]", "etc/foreign_expired_warn");
    }
    else if (login_start_time - cuser.firstlogin > FOREIGN_REG_DAY * 24 * 3600){
        cuser.userlevel &= ~(PERM_LOGINOK | PERM_POST);
        vmsg("警告：請至出入境管理局申請永久居留");
    }
    }
}
#endif


static void
user_login(void)
{
    struct tm       ptime, lasttime;
    int             nowusers, ifbirth = 0, i;

    /* get local time */
    ptime = *localtime4(&now);
    
    /* 初始化: random number 增加user跟時間的差異 */
    mysrand();

    /* show welcome_login */
    if( (ifbirth = (ptime.tm_mday == cuser.day &&
            ptime.tm_mon + 1 == cuser.month)) ){
    more("etc/Welcome_birth", NA);
    }
    else {
#ifndef MULTI_WELCOME_LOGIN
    more("etc/Welcome_login", NA);
#else
    if( SHM->GV2.e.nWelcomes ){
        char            buf[80];
        snprintf(buf, sizeof(buf), "etc/Welcome_login.%d",
             (int)login_start_time % SHM->GV2.e.nWelcomes);
        more(buf, NA);
    }
#endif
    }
    refresh();

    log_usies("ENTER", fromhost);
#ifndef VALGRIND
    setproctitle("%s: %s", margs, cuser.userid);
#endif
    resolve_fcache();
    /* resolve_boards(); */
    numboards = SHM->Bnumber;
    memset(&water[0], 0, sizeof(water_t) * 6);
    strlcpy(water[0].userid, " 全部 ", sizeof(water[0].userid));

    if(getenv("SSH_CLIENT") != NULL){
    struct sockaddr_in xsin;
    char frombuf[50];
    sscanf(getenv("SSH_CLIENT"), "%s", frombuf);
    xsin.sin_family = AF_INET;
    xsin.sin_port = htons(23);
    if (strrchr(frombuf, ':'))
        inet_pton(AF_INET, strrchr(frombuf, ':') + 1, &xsin.sin_addr);
    else
        inet_pton(AF_INET, frombuf, &xsin.sin_addr);
    getremotename(&xsin, fromhost, remoteusername);   /* RFC931 */
    }

    /* 初始化 uinfo、flag、mode */
    setup_utmp(LOGIN);
    currmode = MODE_STARTED;
    enter_uflag = cuser.uflag;
    lasttime = *localtime4(&cuser.lastlogin);

    if ((nowusers = SHM->UTMPnumber) > SHM->max_user) {
    SHM->max_user = nowusers;
    SHM->max_time = now;
    }

    if (!(HasUserPerm(PERM_SYSOP) && HasUserPerm(PERM_SYSOPHIDE)) &&
    !currutmp->invisible)
    {
    /* do_aloha is costly. do it later? */
    do_aloha("<<上站通知>> -- 我來啦！");
    }

    if (SHM->loginmsg.pid){
        if(search_ulist_pid(SHM->loginmsg.pid))
        getmessage(SHM->loginmsg);
        else
        SHM->loginmsg.pid=0;
    }

    if (cuser.userlevel) {  /* not guest */
    move(t_lines - 4, 0);
    clrtobot();
    welcome_msg();

    if( ifbirth ){
        birthday_make_a_wish(&ptime, &lasttime);
        if( getans("是否要顯示「壽星」於使用者名單上？(y/N)") == 'y' )
        currutmp->birth = 1;
    }
    check_bad_login();
    check_mailbox_quota();
    check_register();
    record_lasthost(fromhost);
    restore_backup();

    } else if (strcmp(cuser.userid, STR_GUEST) == 0) { /* guest */

    init_guest_info();
#if 0 // def DBCSAWARE
    u_detectDBCSAwareEvilClient();
#else
    pressanykey();
#endif
    } else {
    pressanykey();
    check_mailbox_quota();
    }

    if(ptime.tm_yday!=lasttime.tm_yday)
    STATINC(STAT_TODAYLOGIN_MAX);

    if (!PERM_HIDE(currutmp)) {
    /* If you wanna do incremental upgrade
     * (like, added a function/flag that wants user to confirm againe)
     * put it here.
     */

#if defined(DBCSAWARE) && defined(DBCSAWARE_UPGRADE_STARTTIME)
    // define the real time you upgraded in your pttbbs.conf
    if(cuser.lastlogin < DBCSAWARE_UPGRADE_STARTTIME)
    {
        if (u_detectDBCSAwareEvilClient())
        cuser.uflag &= ~DBCSAWARE_FLAG;
        else
        cuser.uflag |= DBCSAWARE_FLAG;
    }
#endif
    /* login time update */

    if(ptime.tm_yday!=lasttime.tm_yday)
        STATINC(STAT_TODAYLOGIN_MIN);


    cuser.lastlogin = login_start_time;

    }

#if FOREIGN_REG_DAY > 0
    foreign_warning();
#endif

    passwd_update(usernum, &cuser);

    if(cuser.uflag2 & FAVNEW_FLAG) {
    fav_load();
    if (get_fav_root() != NULL) {
        int num;
        num = updatenewfav(1);
        if (num > NEW_FAV_THRESHOLD &&
        getans("找到 %d 個新看板，確定要加入我的最愛嗎？[Y/n]", num) == 'n') {
        fav_free();
        fav_load();
        }
    }
    }

    for (i = 0; i < NUMVIEWFILE; i++)
    if ((cuser.loginview >> i) & 1)
        more(loginview_file[(int)i][0], YEA);
}

static void
do_aloha(const char *hello)
{
    FILE           *fp;
    char            userid[80];
    char            genbuf[200];

    setuserfile(genbuf, "aloha");
    if ((fp = fopen(genbuf, "r"))) {
    snprintf(genbuf, sizeof(genbuf), hello);
    while (fgets(userid, 80, fp)) {
        userinfo_t     *uentp;
        if ((uentp = (userinfo_t *) search_ulist_userid(userid)) && 
            isvisible(uentp, currutmp)) {
        my_write(uentp->pid, genbuf, uentp->userid, WATERBALL_ALOHA, uentp);
        }
    }
    fclose(fp);
    }
}

static void
do_term_init(void)
{
    term_init();
    initscr();
    if(use_shell_login_mode)
    raise(SIGWINCH);
}

inline static void
start_client(void)
{
#ifdef CPULIMIT
    struct rlimit   rml;
    rml.rlim_cur = CPULIMIT * 60 - 5;
    rml.rlim_max = CPULIMIT * 60;
    setrlimit(RLIMIT_CPU, &rml);
#endif

    STATINC(STAT_LOGIN);
    /* system init */
    nice(2);            /* Ptt: lower priority */
    login_start_time = time(0);
    currmode = 0;

    Signal(SIGHUP, abort_bbs);
    Signal(SIGTERM, abort_bbs);
    Signal(SIGPIPE, abort_bbs);

    Signal(SIGINT, abort_bbs_debug);
    Signal(SIGQUIT, abort_bbs_debug);
    Signal(SIGILL, abort_bbs_debug);
    Signal(SIGABRT, abort_bbs_debug);
    Signal(SIGFPE, abort_bbs_debug);
    Signal(SIGBUS, abort_bbs_debug);
    Signal(SIGSEGV, abort_bbs_debug);
    Signal(SIGXCPU, abort_bbs_debug);

    signal_restart(SIGUSR1, talk_request);
    signal_restart(SIGUSR2, write_request);

    dup2(0, 1);

    /* initialize passwd semaphores */
    if (passwd_init())
    exit(1);

    do_term_init();
    Signal(SIGALRM, abort_bbs);
    alarm(600);

    login_query();      /* Ptt 加上login time out */
    m_init();           /* init the user mail path */
    user_login();
    auto_close_polls();     /* 自動開票 */

    Signal(SIGALRM, SIG_IGN);

    main_menu();
}

/* 取得 remote user name 以判定身份                */
/*
 * rfc931() speaks a common subset of the RFC 931, AUTH, TAP, IDENT and RFC
 * 1413 protocols. It queries an RFC 931 etc. compatible daemon on a remote
 * host to look up the owner of a connection. The information should not be
 * used for authentication purposes. This routine intercepts alarm signals.
 * 
 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
 */

#define RFC931_TIMEOUT   10
#define RFC931_PORT     113 /* Semi-well-known port */
#define ANY_PORT        0   /* Any old port will do */

#if 0
/* timeout - handle timeouts */
static void
timeout(int sig)
{
    longjmp(byebye, sig);
}
#endif

static void
getremotename(const struct sockaddr_in * from, char *rhost, char *rname)
{

    /* get remote host name */

#ifdef FAST_LOGIN
    strcpy(rhost, (char *)inet_ntoa(from->sin_addr));
#else
    struct sockaddr_in our_sin;
    struct sockaddr_in rmt_sin;
    unsigned        rmt_port, rmt_pt;
    unsigned        our_port, our_pt;
    FILE           *fp;
    char            buffer[512], user[80], *cp;
    int             s;
    static struct hostent *hp;


    hp = NULL;
    if (setjmp(byebye) == 0) {
    Signal(SIGALRM, timeout);
    alarm(3);
    hp = gethostbyaddr((char *)&from->sin_addr, sizeof(struct in_addr),
               from->sin_family);
    alarm(0);
    }
    strcpy(rhost, hp ? hp->h_name : (char *)inet_ntoa(from->sin_addr));

    /*
     * Use one unbuffered stdio stream for writing to and for reading from
     * the RFC931 etc. server. This is done because of a bug in the SunOS
     * 4.1.x stdio library. The bug may live in other stdio implementations,
     * too. When we use a single, buffered, bidirectional stdio stream ("r+"
     * or "w+" mode) we read our own output. Such behaviour would make sense
     * with resources that support random-access operations, but not with
     * sockets.
     */

    s = sizeof(our_sin);
    if (getsockname(0, (struct sockaddr *) & our_sin, &s) < 0)
    return;

    if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    return;

    if (!(fp = fdopen(s, "r+"))) {
    close(s);
    return;
    }
    /* Set up a timer so we won't get stuck while waiting for the server. */
    if (setjmp(byebye) == 0) {
    Signal(SIGALRM, timeout);
    alarm(RFC931_TIMEOUT);

    /*
     * Bind the local and remote ends of the query socket to the same IP
     * addresses as the connection under investigation. We go through all
     * this trouble because the local or remote system might have more
     * than one network address. The RFC931 etc. client sends only port
     * numbers; the server takes the IP addresses from the query socket.
     */
    our_pt = ntohs(our_sin.sin_port);
    our_sin.sin_port = htons(ANY_PORT);

    rmt_sin = *from;
    rmt_pt = ntohs(rmt_sin.sin_port);
    rmt_sin.sin_port = htons(RFC931_PORT);

    setbuf(fp, (char *)0);
    s = fileno(fp);

    if (bind(s, (struct sockaddr *) & our_sin, sizeof(our_sin)) >= 0 &&
      connect(s, (struct sockaddr *) & rmt_sin, sizeof(rmt_sin)) >= 0) {
        /*
         * Send query to server. Neglect the risk that a 13-byte write
         * would have to be fragmented by the local system and cause
         * trouble with buggy System V stdio libraries.
         */
        fprintf(fp, "%u,%u\r\n", rmt_pt, our_pt);
        fflush(fp);
        /*
         * Read response from server. Use fgets()/sscanf() so we can work
         * around System V stdio libraries that incorrectly assume EOF
         * when a read from a socket returns less than requested.
         */
        if (fgets(buffer, sizeof(buffer), fp) && !ferror(fp)
        && !feof(fp)
        && sscanf(buffer, "%u , %u : USERID :%*[^:]:%79s", &rmt_port,
              &our_port, user) == 3 && rmt_pt == rmt_port
        && our_pt == our_port) {

        /*
         * Strip trailing carriage return. It is part of the
         * protocol, not part of the data.
         */
        if ((cp = (char *)strchr(user, '\r')))
            *cp = 0;
        strlcpy(rname, user, sizeof(user));
        }
    }
    alarm(0);
    }
    fclose(fp);
#endif
}

static int
bind_port(int port)
{
    int             sock, on, sz;
    struct linger   lin;
    struct sockaddr_in xsin;

    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    on = 1;
    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on));
    setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof(on));

    lin.l_onoff = 0;
    setsockopt(sock, SOL_SOCKET, SO_LINGER, &lin, sizeof(lin));

    sz = 1024;
    setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void*)&sz, sizeof(sz));
    sz = 4096;
    setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (void*)&sz, sizeof(sz));

    xsin.sin_family = AF_INET;
    xsin.sin_addr.s_addr = htonl(INADDR_ANY);
    xsin.sin_port = htons(port);
    if (bind(sock, (struct sockaddr *) & xsin, sizeof xsin) < 0) {
    syslog(LOG_INFO, "bbsd bind_port can't bind to %d", port);
    exit(1);
    }
    if (listen(sock, SOCKET_QLEN) < 0) {
    syslog(LOG_INFO, "bbsd bind_port can't listen to %d", port);
    exit(1);
    }
    return sock;
}


/*******************************************************/


static int      shell_login(int argc, char *argv[], char *envp[]);
static int      daemon_login(int argc, char *argv[], char *envp[]);
static int      check_ban_and_load(int fd);

int
main(int argc, char *argv[], char *envp[])
{
    start_time = time(NULL);

    /* avoid SIGPIPE */
    Signal(SIGPIPE, SIG_IGN);

    /* avoid erroneous signal from other mbbsd */
    Signal(SIGUSR1, SIG_IGN);
    Signal(SIGUSR2, SIG_IGN);

#if defined(__GLIBC__) && defined(CRITICAL_MEMORY)
    #define MY__MMAP_THRESHOLD (1024 * 8)
    #define MY__MMAP_MAX (0)
    #define MY__TRIM_THRESHOLD (1024 * 8)
    #define MY__TOP_PAD (0)

    mallopt (M_MMAP_THRESHOLD, MY__MMAP_THRESHOLD);
    mallopt (M_MMAP_MAX, MY__MMAP_MAX);
    mallopt (M_TRIM_THRESHOLD, MY__TRIM_THRESHOLD);
    mallopt (M_TOP_PAD, MY__TOP_PAD);
#endif
    
    attach_SHM();
    if( (argc == 3 && shell_login(argc, argv, envp)) ||
    (argc != 3 && daemon_login(argc, argv, envp)) )
    start_client();

    return 0;
}

static int
shell_login(int argc, char *argv[], char *envp[])
{

    STATINC(STAT_SHELLLOGIN);
    /* Give up root privileges: no way back from here */
    setgid(BBSGID);
    setuid(BBSUID);
    chdir(BBSHOME);

#if defined(linux) && defined(DEBUG)
//    mtrace();
#endif

    use_shell_login_mode = 1;
    initsetproctitle(argc, argv, envp);

    snprintf(margs, sizeof(margs), "%s ssh ", argv[0]);
    /*
     * copy fromindent: Standard input:1138: Error:Unexpected end of file the
     * original "bbs"
     */
    if (argc > 1) {
    strcpy(fromhost, argv[1]);
    if (argc > 3)
        strlcpy(remoteusername, argv[3], sizeof(remoteusername));
    }
    close(2);
    /* don't close fd 1, at least init_tty need it */

    init_tty();
    if (check_ban_and_load(0)) {
#ifdef OVERLOADBLOCKFDS
    sleep(10);
#endif
    return 0;
    }
    return 1;
}

void telnet_init(void);
unsigned int telnet_handler(unsigned char c) ;

static int
daemon_login(int argc, char *argv[], char *envp[])
{
    int             msock, csock;   /* socket for Master and Child */
    FILE           *fp;
    int             listen_port = 23;
    int             len_of_sock_addr, overloading = 0;
    char            buf[256];
#if OVERLOADBLOCKFDS
    int             blockfd[OVERLOADBLOCKFDS];
    int             i, nblocked = 0;
#endif
    struct sockaddr_in xsin;
    xsin.sin_family = AF_INET;

    /* setup standalone */

    start_daemon();

    signal_restart(SIGCHLD, reapchild);

    /* choose port */
    if (argc == 1)
    listen_port = 3006;
    else if (argc >= 2)
    listen_port = atoi(argv[1]);

    snprintf(margs, sizeof(margs), "%s %d ", argv[0], listen_port);

    /* port binding */
    msock = bind_port(listen_port);
    if (msock < 0) {
    syslog(LOG_INFO, "mbbsd bind_port failed.\n");
    exit(1);
    }
    initsetproctitle(argc, argv, envp);
#ifndef VALGRIND
    setproctitle("%s: listening ", margs);
#endif

    /* Give up root privileges: no way back from here */
    setgid(BBSGID);
    setuid(BBSUID);
    chdir(BBSHOME);

    /* It's better to do something before fork */
#ifdef CONVERT
    big2gb_init(NULL);
    gb2big_init(NULL);
    big2uni_init(NULL);
    uni2big_init(NULL);
#endif
    
#ifndef NO_FORK
#ifdef PRE_FORK
    if( listen_port == 23 ){ // only pre-fork in port 23
    int     i;
    for( i = 0 ; i < PRE_FORK ; ++i )
        if( fork() <= 0 )
        break;
    }
#endif
#endif

    snprintf(buf, sizeof(buf), "run/mbbsd.%d.%d.pid", listen_port, (int)getpid());
    if ((fp = fopen(buf, "w"))) {
    fprintf(fp, "%d\n", (int)getpid());
    fclose(fp);
    }

    /* main loop */
    while( 1 ){
    len_of_sock_addr = sizeof(xsin);
#if defined(Solaris) && __OS_MAJOR_VERSION__ == 5 && __OS_MINOR_VERSION__ < 7
    if( (csock = accept(msock, (struct sockaddr *)&xsin,
                &len_of_sock_addr)) < 0 ){
#else
    if( (csock = accept(msock, (struct sockaddr *)&xsin,
                (socklen_t *)&len_of_sock_addr)) < 0 ){
#endif
        if (errno != EINTR)
        sleep(1);
        continue;
    }

    overloading = check_ban_and_load(csock);
#if OVERLOADBLOCKFDS
    if( (!overloading && nblocked) ||
        (overloading && nblocked == OVERLOADBLOCKFDS) ){
        for( i = 0 ; i < OVERLOADBLOCKFDS ; ++i )
        if( blockfd[i] != csock && blockfd[i] != msock )
            /* blockfd[i] should not be msock, but it happened */
            close(blockfd[i]);
        nblocked = 0;
    }
#endif

    if( overloading ){
#if OVERLOADBLOCKFDS
        blockfd[nblocked++] = csock;
#else
        close(csock);
#endif
        continue;
    }

#ifdef NO_FORK
    break;
#else
    if (fork() == 0)
        break;
    else
        close(csock);
#endif
    }
    /* here is only child running */

#ifndef VALGRIND
    setproctitle("%s: ...login wait... ", margs);
#endif
    close(msock);
    dup2(csock, 0);
    close(csock);

    getremotename(&xsin, fromhost, remoteusername);
    telnet_init();
    return 1;
}

/*
 * check if we're banning login and if the load is too high. if login is
 * permitted, return 0; else return -1; approriate message is output to fd.
 */
static int
check_ban_and_load(int fd)
{
    FILE           *fp;
    static time4_t   chkload_time = 0;
    static int      overload = 0;   /* overload or banned, update every 1
                     * sec  */
    static int      banned = 0;

#ifdef INSCREEN
    write(fd, INSCREEN, sizeof(INSCREEN));
#else
#define BANNER \
"【" BBSNAME "】◎ 台大流行網 ◎(" MYHOSTNAME ") 調幅(" MYIP ") \r\n"
    write(fd, BANNER, sizeof(BANNER));
#endif

    if ((time(0) - chkload_time) > 1) {
    overload = 0;
    banned = 0;

    if(cpuload(NULL) > MAX_CPULOAD)
        overload = 1;
    else if (SHM->UTMPnumber >= MAX_ACTIVE
#ifdef DYMAX_ACTIVE
        || (SHM->GV2.e.dymaxactive > 2000 &&
            SHM->UTMPnumber >= SHM->GV2.e.dymaxactive)
#endif
        ) {
        ++SHM->GV2.e.toomanyusers;
        overload = 2;
    } else if(!access(BBSHOME "/" BAN_FILE, R_OK))
        banned = 1;

    chkload_time = time(0);
    }

    if(overload == 1)
    write(fd, "系統過載, 請稍後再來\r\n", 22);
    else if(overload == 2)
    write(fd, "由於人數過多，請您稍後再來。", 28);
    else if (banned && (fp = fopen(BBSHOME "/" BAN_FILE, "r"))) {
    char     buf[256];
    while (fgets(buf, sizeof(buf), fp))
        write(fd, buf, strlen(buf));
    fclose(fp);
    }

    if (banned || overload)
    return -1;

    return 0;
}

/* ------- piaip's implementation of TELNET protocol ------- */

enum {
    IAC_NONE,
    IAC_COMMAND,
    IAC_WAIT_OPT,
    IAC_WAIT_SE,
    IAC_PROCESS_OPT,
    IAC_ERROR
} TELNET_IAC_STATES;

static unsigned char iac_state = 0; /* as byte to reduce memory */

#define TELNET_IAC_MAXLEN (16)
/* We don't reply to most commands, so this maxlen can be minimal.
 * Warning: if you want to support ENV passing or other long commands,
 * remember to increase this value. Howver, some poorly implemented
 * terminals like xxMan may not follow the protocols and user will hang
 * on those terminals when IACs were sent.
 */

void
telnet_init(void)
{
    /* We are the boss. We don't respect to client.
     * It's client's responsibility to follow us.
     * Please write these codes in i-dont-care opt handlers.
     */
    const char telnet_init_cmds[] = {
    /* retrieve terminal type and throw away.
     * why? because without this, clients enter line mode.
     */
    IAC, DO, TELOPT_TTYPE,
    IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE,

    /* i'm a smart term with resize ability. */
    IAC, DO, TELOPT_NAWS,

    /* i will echo. */
    IAC, WILL, TELOPT_ECHO,
    /* supress ga. */
    IAC, WILL, TELOPT_SGA,
    /* 8 bit binary. */
    IAC, WILL, TELOPT_BINARY,
    IAC, DO,   TELOPT_BINARY,
    };

    raw_connection = 1;
    write(0, telnet_init_cmds, sizeof(telnet_init_cmds));
}

/* tty_read
 * read from tty, process telnet commands if raw connection.
 * return: >0 = length, <=0 means read more, abort/eof is automatically processed.
 */
ssize_t
tty_read(unsigned char *buf, size_t max)
{
    ssize_t l = read(0, buf, max);

    if(l == 0 || (l < 0 && !(errno == EINTR || errno == EAGAIN)))
    abort_bbs(0);

    if(!raw_connection)
    return l;

    /* process buffer */
    if (l > 0) {
    unsigned char *buf2 = buf;
    size_t i = 0, i2 = 0;

    /* prescan. because IAC is rare, 
     * this cost is worthy. */
    if (iac_state == IAC_NONE && memchr(buf, IAC, l) == NULL)
        return l;

    /* we have to look into the buffer. */
    for (i = 0; i < l; i++, buf++)
        if(telnet_handler(*buf) == 0)
        *(buf2++) = *buf;
        else
        i2 ++;
    l = (i2 == l) ? -1L : l - i2;
    }
    return l;
}

/* input:  raw character
 * output: telnet command if c was handled, otherwise zero.
 */
unsigned int 
telnet_handler(unsigned char c) 
{
    static unsigned char iac_quote = 0; /* as byte to reduce memory */
    static unsigned char iac_opt_req = 0;

    static unsigned char iac_buf[TELNET_IAC_MAXLEN];
    static unsigned int  iac_buflen = 0;

    /* we have to quote all IACs. */
    if(c == IAC && !iac_quote) {
    iac_quote = 1;
    return NOP;
    }

    /* a special case is the top level iac. otherwise, iac is just a quote. */
    if (iac_quote) {
    if(iac_state == IAC_NONE)
        iac_state = IAC_COMMAND;
    if(iac_state == IAC_WAIT_SE && c == SE)
        iac_state = IAC_PROCESS_OPT;
    iac_quote = 0;
    }

    /* now, let's process commands by state */
    switch(iac_state) {

    case IAC_NONE:
        return 0;

    case IAC_COMMAND:
#ifdef DEBUG
        {
        int cx = c; /* to make compiler happy */
        write(0, "-", 1);
        if(TELCMD_OK(cx))
            write(0, TELCMD(c), strlen(TELCMD(c)));
        write(0, " ", 1);
        }
#endif
        iac_state = IAC_NONE; /* by default we restore state. */
        switch(c) {
        case IAC:
            return 0;

        /* we don't want to process these. or maybe in future. */
        case BREAK:           /* break */
        case ABORT:           /* Abort process */
        case SUSP:            /* Suspend process */
        case AO:              /* abort output--but let prog finish */
        case IP:              /* interrupt process--permanently */
        case EOR:             /* end of record (transparent mode) */
        case DM:              /* data mark--for connect. cleaning */
        case xEOF:            /* End of file: EOF is already used... */
            return NOP;

        case NOP:             /* nop */
            return NOP;

        /* we should process these, but maybe in future. */
        case GA:              /* you may reverse the line */
        case EL:              /* erase the current line */
        case EC:              /* erase the current character */
            return NOP;

        /* good */
        case AYT:             /* are you there */
            {
                const char *alive = "I'm still alive, loading: ";
                char buf[STRLEN];

                /* respond as fast as we can */
                write(0, alive, strlen(alive));
                cpuload(buf);
                write(0, buf, strlen(buf));
                write(0, "\r\n", 2);
            }
            return NOP;

        case DONT:            /* you are not to use option */
        case DO:              /* please, you use option */
        case WONT:            /* I won't use option */
        case WILL:            /* I will use option */
            iac_opt_req = c;
            iac_state = IAC_WAIT_OPT;
            return NOP;

        case SB:              /* interpret as subnegotiation */
            iac_state = IAC_WAIT_SE;
            iac_buflen = 0;
            return NOP;

        case SE:              /* end sub negotiation */
        default:
            return NOP;
        }
        return 1;

    case IAC_WAIT_OPT:
#ifdef DEBUG
        write(0, "-", 1);
        if(TELOPT_OK(c))
        write(0, TELOPT(c), strlen(TELOPT(c)));
        write(0, " ", 1);
#endif
        iac_state = IAC_NONE;
        /*
         * According to RFC, there're some tricky steps to prevent loop.
         * However because we have a poor term which does not allow 
         * most abilities, let's be a strong boss here.
         *
         * Although my old imeplementation worked, it's even better to follow this:
         * http://www.tcpipguide.com/free/t_TelnetOptionsandOptionNegotiation-3.htm
         */
        switch(c) {
        /* i-dont-care: i don't care about what client is. 
         * these should be clamed in init and
         * client must follow me. */
        case TELOPT_TTYPE:  /* termtype or line. */
        case TELOPT_NAWS:       /* resize terminal */
        case TELOPT_SGA:    /* supress GA */
        case TELOPT_ECHO:       /* echo */
        case TELOPT_BINARY: /* we are CJK. */
            break;

        /* i-dont-agree: i don't understand/agree these.
         * according to RFC, saying NO stopped further
         * requests so there'll not be endless loop. */
        case TELOPT_RCP:         /* prepare to reconnect */
        default:
            if (iac_opt_req == WILL || iac_opt_req == DO)
            {
            /* unknown option, reply with won't */
            unsigned char cmd[3] = { IAC, DONT, 0 };
            if(iac_opt_req == DO) cmd[1] = WONT;
            cmd[2] = c;
            write(0, cmd, sizeof(cmd));
            }
            break;
        }
        return 1;

    case IAC_WAIT_SE:
        iac_buf[iac_buflen++] = c;
        /* no need to convert state because previous quoting will do. */
            
        if(iac_buflen == TELNET_IAC_MAXLEN) {
        /* may be broken protocol?
         * whether finished or not, break for safety 
         * or user may be frozen.
         */
        iac_state = IAC_NONE;
        return 0;
        }
        return 1;

    case IAC_PROCESS_OPT:
        iac_state = IAC_NONE;
#ifdef DEBUG
        write(0, "-", 1);
        if(TELOPT_OK(iac_buf[0]))
        write(0, TELOPT(iac_buf[0]), strlen(TELOPT(iac_buf[0])));
        write(0, " ", 1);
#endif
        switch(iac_buf[0]) {

        /* resize terminal */
        case TELOPT_NAWS:
            {
            int w = (iac_buf[1] << 8) + (iac_buf[2]);
            int h = (iac_buf[3] << 8) + (iac_buf[4]);
                term_resize(w, h);
            }
            break;

        default:
            break;
        }
        return 1;
    }
    return 1; /* never reached */
}
/* vim: sw=4 
 */