HT的cgi处理过程

主要是cgi-bin/www文件处理客户请求的过程 用 http://domain/SMAGIC/boa 这样子。。这样的 cgi 对应的程序就是 nju09/ 下的 bbsboa.c

apache的httpd.conf里设置了cgi-bin的目录路径和调用的可执行处理文件 www，然后客户端浏览器发送的请求(形如 http://your_domain/SMGICXXXX )就直接通过 apache 调用 www 进行处理。

一、分析cgi环境变量 SCRIPT_URL 在BBSLIB.c里，url_parse()函数定义：

int
url_parse()
{
    char *url, *end, name[STRLEN], *p, *extraparam;
    url = getenv("SCRIPT_URL");
    if (NULL == url) {
        char buf[1024];
        url = getenv("REQUEST_URI");
        if (NULL == url)
            return -1;
        strsncpy(buf, url, sizeof (buf));
        if ((end = strchr(buf, '?')))
            *end = 0;
        setenv("SCRIPT_URL", buf, 0);
    }
    strcpy(name, "/");
#ifdef USESESSIONCOOKIE
    if (strcmp(url, "/")) {
        strsncpy(name, getparm("SESSION"), sizeof (name));
    }
    if (!strncmp(url, "/" SMAGIC, sizeof (SMAGIC))) {
        //兼容 telnet
        if (!name[1]) {
            snprintf(name, STRLEN, "%s", url + sizeof (SMAGIC));
            p = strchr(name, '/');
            if (p)
                *p = 0;
        }

        p = strchr(url + sizeof (SMAGIC), '/');
        if (NULL != p) {
            url = strchr(url + 1, '/');
        } else
            return -1;

    }
#else
    if (!strncmp(url, "/" SMAGIC, sizeof (SMAGIC))) {
        snprintf(name, STRLEN, "%s", url + sizeof (SMAGIC));
        p = strchr(name, '/');
        if (NULL != p) {
            *p = 0;
            url = strchr(url + 1, '/');
        } else
            return -1;
    }
#endif
    extraparam = strchr(name, '_');
    if (extraparam) {
        *extraparam = 0;
        extraparam++;
    } else
        extraparam = "";
    extraparam_init(extraparam);
    loginok = user_init(&currentuser, &u_info, name);
    if (loginok)
        w_info = &(u_info->wwwinfo);
    else
        w_info = &guest;

    snprintf(needcgi, STRLEN, "%s", url + 1);
    if ((end = strchr(needcgi, '?')) != NULL)
        *end = 0;

    if (!*needcgi || nologin) {
        strcpy(needcgi, "bbsindex");
        strcpy(rframe, "");
        strsncpy(name, getsenv("HTTP_HOST"), 70);
        p = strchr(name, '.');
        if (p != NULL && isaword(domainname, p + 1)) {
            *p = 0;
            strsncpy(rframe, name, 60);
        }
        if (rframe[0] && isaword(specname, rframe))
            rframe[0] = 0;
        return 0;
    }
    if (NULL != (end = strchr(needcgi, '/')))
        *end = 0;
    return 0;
}

二、bbsmain.c 里这样调用 url_parse()

int
main(int argc, char *argv[])
{
    struct cgi_applet *a = NULL;
    struct rlimit rl;
    int i;
    struct in_addr in;
    seteuid(BBSUID);
    setuid(BBSUID);
    setgid(BBSGID);
    cgi_time(NULL);
    rl.rlim_cur = 100 * 1024 * 1024;
    rl.rlim_max = 100 * 1024 * 1024;
    setrlimit(RLIMIT_CORE, &rl);
    thispid = getpid();
    now_t = time(NULL);
    srand(now_t * 2 + thispid);
    if (initbbsinfo(&bbsinfo) < 0)
        exit(0);
    if (uhash_uptime() == 0) {
        exit(-1);
    }
    wwwcache = bbsinfo.wwwcache;
    thisversion = file_time(argv[0]);
#ifndef USEBIG5
    if (thisversion > wwwcache->www_version)
        wwwcache->www_version = thisversion;
#endif
    html_header(0);
    if (geteuid() != BBSUID)
        http_fatal("uid error.");
    chdir(BBSHOME);
    shm_init(&bbsinfo);
    signal(SIGTERM, wantquit);
    if (access("NOLOGIN", F_OK))
        nologin = 0;
    get_att_server();
    get_tjpg_server();
#ifdef ENABLE_FASTCGI
    atexit(FCGI_Finish);
#endif
    while (1) {
        accepting = 1;
        if (shouldExit || wwwcache->www_version > thisversion
            || rt++ > 400000) {
            accepting = 0;
            break;
        }
        if (FCGI_Accept() < 0) {
            accepting = 0;
            break;
        }
        accepting = 0;
#ifdef USEBIG5
        start_outcache();
#endif
        cginame = NULL;
        if (setjmp(cgi_start)) {
#ifdef USEBIG5
            end_outcache();
#endif
            cgi_time(a);
            continue;
        }
        html_header(0);
        hsprintf(NULL, NULL);
        now_t = time(NULL);
        via_proxy = 0;
        strsncpy(realfromhost, getsenv("REMOTE_ADDR"),
             sizeof (realfromhost));
        inet_aton(realfromhost, &from_addr);
        in = from_addr;
        in.s_addr &= 0x0000ffff;
        strsncpy(fromhost, inet_ntoa(in), sizeof (fromhost));
        for (i = 0; wwwcache->validproxy[i] && i < MAX_PROXY_NUM; i++) {
            if (from_addr.s_addr == wwwcache->validproxy[i]) {
                via_proxy = 1;
                break;
            }
        }
        if (via_proxy
            || from_addr.s_addr == wwwcache->accel_addr.s_addr) {
            char *ptr, *p;
            ptr = getenv("HTTP_X_FORWARDED_FOR");
            if (!ptr)
                ptr = getsenv("REMOTE_ADDR");
            p = strrchr(ptr, ',');
            if (p != NULL) {
                while (!isdigit(*p) && *p)
                    p++;
                if (*p)
                    strsncpy(realfromhost, p,
                         sizeof (realfromhost));
                else
                    strsncpy(realfromhost, ptr,
                         sizeof (realfromhost));
            } else
                strsncpy(realfromhost, ptr,
                     sizeof (realfromhost));
            inet_aton(realfromhost, &from_addr);
            in = from_addr;
            in.s_addr &= 0x0000ffff;
            strsncpy(fromhost, inet_ntoa(in), sizeof (fromhost));
        }
        http_parm_init();
        if (url_parse())
            http_fatal("%s 没有实现的功能1!",
                   getsenv("SCRIPT_URL"));
        brc_expired();
        a = get_cgi_applet(needcgi);
        if (a != NULL) {
            cginame = a->name[0];
            //access(getsenv("QUERY_STRING"), F_OK);
            wwwcache->www_visit++;
            (*(a->main)) ();
#ifdef USEBIG5
            end_outcache();
#endif
            cgi_time(a);
            continue;
        }
        http_fatal("%s 没有实现的功能2!", getsenv("SCRIPT_URL"));
//              end_outcache();
    }
    logtimeused();
    exit(5);
}

三、main()调用url_parse()以后，看url_parse()里面大略做的是： 先得到环境变量SCRIPT_URL的值，如上面的就是SCRIPT_URL="/SMAGIC/boa" 然后，截掉前面的部分，把剩下的boa赋给needcgi，然后返回main()， 然后main()以needcgi为参数调用get_cgi_applet(),根据needcgi从applets表中查到函数名

struct cgi_applet *
get_cgi_applet(char *needcgi)
{
    static ght_hash_table_t *p_table = NULL;
    struct cgi_applet *a;

    if (p_table == NULL) {
        int i;
        a = applets;
        p_table = ght_create(250);
        while (a->main != NULL) {
            a->count = 0;
            a->utime = 0;
            a->stime = 0;
            for (i = 0; a->name[i] != NULL; i++)
                ght_insert(p_table, (void *) a,
                       strlen(a->name[i]),
                       (void *) a->name[i]);
            a++;
        }
    }
    if (p_table == NULL)
        return NULL;
    return ght_get(p_table, strlen(needcgi), needcgi);
}
#else
struct cgi_applet *
get_cgi_applet(char *needcgi)
{
    struct cgi_applet *a;
    int i;
    a = applets;
    while (a->main != NULL) {
        for (i = 0; a->name[i] != NULL; i++)
            if (!strcmp(needcgi, a->name[i]))
                return a;
        a++;
    }
    return NULL;
}
#endif

既然url_parse()这样写的，http://domain/cgi-bin/www 自然不行啦..

四、据needcgi从applets表中查到函数名，以下是可供/var/www/cgi-bin/下的可执行文件www调用的内部函数：

struct cgi_applet applets[] = {
//      {bbsusr_main, {"bbsusr", NULL}},
    {bbsucss_main, {"bbsucss", NULL}},
    {bbsdefcss_main, {"bbsdefcss", NULL}},
    {bbstop10_main, {"bbstop10", NULL}},
    {bbsdoc_main, {"bbsdoc", "doc", NULL}},
    {bbscon_main, {"bbscon", "con", NULL}},
    {bbsbrdadd_main, {"bbsbrdadd", "brdadd", NULL}},
    {bbsboa_main, {"bbsboa", "boa", NULL}},
    {bbsall_main, {"bbsall", NULL}},
    {bbsanc_main, {"bbsanc", "anc", NULL}},
    {bbs0an_main, {"bbs0an", "0an", NULL}},
    {bbslogout_main, {"bbslogout", NULL}},
    {bbsleft_main, {"bbsleft", NULL}},
    {bbslogin_main, {"bbslogin", NULL}},
    {bbsbadlogins_main, {"bbsbadlogins", NULL}},
    {bbsqry_main, {"bbsqry", "qry", NULL}},
    {bbsnot_main, {"bbsnot", "not", NULL}},
    {bbsfind_main, {"bbsfind", NULL}},
    {bbsfadd_main, {"bbsfadd", NULL}},
    {bbsfdel_main, {"bbsfdel", NULL}},
    {bbsfall_main, {"bbsfall", NULL}},
    {bbsfriend_main, {"bbsfriend", NULL}},
    {bbsfoot_main, {"bbsfoot", NULL}},
    {bbsform_main, {"bbsform", NULL}},
    {bbspwd_main, {"bbspwd", NULL}},
    {bbsplan_main, {"bbsplan", NULL}},
    {bbsinfo_main, {"bbsinfo", NULL}},
    {bbsmypic_main, {"bbsmypic", "mypic", NULL}},
    {bbsmybrd_main, {"bbsmybrd", NULL}},
    {bbssig_main, {"bbssig", NULL}},
    {bbspst_main, {"bbspst", "pst", NULL}},
    {bbsgcon_main, {"bbsgcon", "gcon", NULL}},
    {bbsgdoc_main, {"bbsgdoc", "gdoc", NULL}},
    {bbsdel_main, {"bbsdel", "del", NULL}},
    {bbsdelmail_main, {"bbsdelmail", NULL}},
    {bbsmailcon_main, {"bbsmailcon", NULL}},
    {bbsmail_main, {"bbsmail", "mail", NULL}},
    {bbsdelmsg_main, {"bbsdelmsg", NULL}},
    {bbssnd_main, {"bbssnd", NULL}},
    {bbsnotepad_main, {"bbsnotepad", NULL}},
    {bbsmsg_main, {"bbsmsg", NULL}},
    {bbssendmsg_main, {"bbssendmsg", NULL}},
#ifdef ENABLE_EMAILREG
    {bbsreg_main, {"bbsreg", NULL}},
    {bbsemailreg_main, {"bbsemailreg", NULL}},
    {bbsemailconfirm_main, {"bbsemailconfirm", "emailconfirm", NULL}},
#else
    {bbsreg_main, {"bbsreg", "bbsemailreg", NULL}},
#endif
#ifdef ENABLE_INVITATION
    {bbsinvite_main, {"bbsinvite", "invite", NULL}},
    {bbsinviteconfirm_main, {"bbsinviteconfirm", "inviteconfirm", NULL}},
#endif
    {bbsscanreg_main, {"bbsscanreg", NULL}},
    {bbsmailmsg_main, {"bbsmailmsg", NULL}},
    {bbssndmail_main, {"bbssndmail", NULL}},
    {bbsnewmail_main, {"bbsnewmail", NULL}},
    {bbspstmail_main, {"bbspstmail", "pstmail", NULL}},
    {bbsgetmsg_main, {"bbsgetmsg", NULL}},
    //{bbschat_main, {"bbschat", NULL}},
    {bbscloak_main, {"bbscloak", NULL}},
    {bbsmdoc_main, {"bbsmdoc", "mdoc", NULL}},
    {bbsnick_main, {"bbsnick", NULL}},
    {bbstfind_main, {"bbstfind", "tfind", NULL}},
    {bbsadl_main, {"bbsadl", NULL}},
    {bbstcon_main, {"bbstcon", "tcon", NULL}},
    {bbstdoc_main, {"bbstdoc", "tdoc", NULL}},
    {bbsdoreg_main, {"bbsdoreg", NULL}},
    {bbsmywww_main, {"bbsmywww", NULL}},
    {bbsccc_main, {"bbsccc", "ccc", NULL}},
    //{bbsufind_main, {"bbsufind", NULL}},
    {bbsclear_main, {"bbsclear", "clear", NULL}},
    {bbsstat_main, {"bbsstat", NULL}},
    {bbsedit_main, {"bbsedit", "edit", NULL}},
    {bbsman_main, {"bbsman", "man", NULL}},
    {bbsparm_main, {"bbsparm", NULL}},
    {bbsfwd_main, {"bbsfwd", "fwd", NULL}},
    {bbsmnote_main, {"bbsmnote", NULL}},
    {bbsdenyall_main, {"bbsdenyall", NULL}},
    {bbsdenydel_main, {"bbsdenydel", NULL}},
    {bbsdenyadd_main, {"bbsdenyadd", NULL}},
    {bbstopb10_main, {"bbstopb10", NULL}},
    {bbsbfind_main, {"bbsbfind", "bfind", NULL}},
    {bbsx_main, {"bbsx", NULL}},
    {bbseva_main, {"bbseva", "eva", NULL}},
    {bbsvote_main, {"bbsvote", "vote", NULL}},
    {bbsshownav_main, {"bbsshownav", NULL}},
    {bbsbkndoc_main, {"bbsbkndoc", "bkndoc", NULL}},
    {bbsbknsel_main, {"bbsbknsel", "bknsel", NULL}},
    {bbsbkncon_main, {"bbsbkncon", "bkncon", NULL}},
    {bbshome_main, {"bbshome", "home", NULL}},
    {bbsindex_main, {"bbsindex", "index", NULL}},
//      {bbsupload_main, {"bbsupload", NULL}},
    {bbslform_main, {"bbslform", NULL}},
    {bbslt_main, {"bbslt", NULL}},
    {bbsdt_main, {"bbsdt", NULL}},
    {regreq_main, {"regreq", NULL}},
    {bbsselstyle_main, {"bbsselstyle", NULL}},
    {bbscon1_main, {"bbscon1", "c1", NULL}},
    {bbsattach_main, {"attach", NULL}},
    {bbskick_main, {"kick", NULL}},
    {bbsshowfile_main, {"bbsshowfile", "showfile", NULL}},
    {bbsincon_main, {"boards", NULL}},
    {NULL}
};