mod_cgi.c

apache简化版

    int i;
#endif

    char **env;

    RAISE_SIGSTOP(CGI_CHILD);
#ifdef DEBUG_CGI
    fprintf(dbg, "Attempting to exec %s as %sCGI child (argv0 = %s)\n",
	    r->filename, cld->nph ? "NPH " : "", argv0);
#endif

    ap_add_cgi_vars(r);
    env = ap_create_environment(r->pool, r->subprocess_env);

#ifdef DEBUG_CGI
    fprintf(dbg, "Environment: \n");
    for (i = 0; env[i]; ++i)
	fprintf(dbg, "'%s'\n", env[i]);
#endif

#ifndef WIN32
    ap_chdir_file(r->filename);
#endif
    if (!cld->debug)
	ap_error_log2stderr(r->server);

    /* Transumute outselves into the script.
     * NB only ISINDEX scripts get decoded arguments.
     */

    ap_cleanup_for_exec();

    child_pid = ap_call_exec(r, pinfo, argv0, env, 0);
#ifdef WIN32
    return (child_pid);
#else

    /* Uh oh.  Still here.  Where's the kaboom?  There was supposed to be an
     * EARTH-shattering kaboom!
     *
     * Oh, well.  Muddle through as best we can...
     *
     * Note that only stderr is available at this point, so don't pass in
     * a server to aplog_error.
     */

    ap_log_error(APLOG_MARK, APLOG_ERR, NULL, "exec of %s failed", r->filename);
    exit(0);
    /* NOT REACHED */
    return (0);
#endif
}

static int cgi_handler(request_rec *r)
{
    int retval, nph, dbpos = 0;
    char *argv0, *dbuf = NULL;
    BUFF *script_out, *script_in, *script_err;
    char argsbuffer[HUGE_STRING_LEN];
    int is_included = !strcmp(r->protocol, "INCLUDED");
    void *sconf = r->server->module_config;
    cgi_server_conf *conf =
    (cgi_server_conf *) ap_get_module_config(sconf, &cgi_module);

    struct cgi_child_stuff cld;

    if (r->method_number == M_OPTIONS) {
	/* 99 out of 100 CGI scripts, this is all they support */
	r->allowed |= (1 << M_GET);
	r->allowed |= (1 << M_POST);
	return DECLINED;
    }

    if ((argv0 = strrchr(r->filename, '/')) != NULL)
	argv0++;
    else
	argv0 = r->filename;

    nph = !(strncmp(argv0, "nph-", 4));

    if (!(ap_allow_options(r) & OPT_EXECCGI) && !is_scriptaliased(r))
	return log_scripterror(r, conf, FORBIDDEN, APLOG_NOERRNO,
			       "Options ExecCGI is off in this directory");
    if (nph && is_included)
	return log_scripterror(r, conf, FORBIDDEN, APLOG_NOERRNO,
			       "attempt to include NPH CGI script");

#if defined(OS2) || defined(WIN32)
    /* Allow for cgi files without the .EXE extension on them under OS/2 */
    if (r->finfo.st_mode == 0) {
	struct stat statbuf;

	r->filename = ap_pstrcat(r->pool, r->filename, ".EXE", NULL);

	if ((stat(r->filename, &statbuf) != 0) || (!S_ISREG(statbuf.st_mode))) {
	    return log_scripterror(r, conf, NOT_FOUND, 0,
				   "script not found or unable to stat");
	}
    }
#else
    if (r->finfo.st_mode == 0)
	return log_scripterror(r, conf, NOT_FOUND, APLOG_NOERRNO,
			       "script not found or unable to stat");
#endif
    if (S_ISDIR(r->finfo.st_mode))
	return log_scripterror(r, conf, FORBIDDEN, APLOG_NOERRNO,
			       "attempt to invoke directory as script");
    if (!ap_suexec_enabled) {
	if (!ap_can_exec(&r->finfo))
	    return log_scripterror(r, conf, FORBIDDEN, APLOG_NOERRNO,
				   "file permissions deny server execution");
    }

    if ((retval = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)))
	return retval;

    ap_add_common_vars(r);
    cld.argv0 = argv0;
    cld.r = r;
    cld.nph = nph;
    cld.debug = conf->logname ? 1 : 0;

#ifdef CHARSET_EBCDIC
    /* XXX:@@@ Is the generated/included output ALWAYS in text/ebcdic format? */
    /* Or must we check the Content-Type first? */
    ap_bsetflag(r->connection->client, B_EBCDIC2ASCII, 1);
#endif /*CHARSET_EBCDIC*/

    /*
     * we spawn out of r->main if it's there so that we can avoid
     * waiting for free_proc_chain to cleanup in the middle of an
     * SSI request -djg
     */
    if (!ap_bspawn_child(r->main ? r->main->pool : r->pool, cgi_child,
			 (void *) &cld, kill_after_timeout,
			 &script_out, &script_in, &script_err)) {
	ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
		    "couldn't spawn child process: %s", r->filename);
	return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* Transfer any put/post args, CERN style...
     * Note that if a buggy script fails to read everything we throw
     * at it, or a buggy client sends too much, we get a SIGPIPE, so
     * we have to ignore SIGPIPE while doing this.  CERN does the same
     * (and in fact, they pretty nearly guarantee themselves a SIGPIPE
     * on every invocation by chasing the real client data with a
     * spurious newline).
     */

    if (ap_should_client_block(r)) {
	void (*handler) (int);
	int dbsize, len_read;

	if (conf->logname) {
	    dbuf = ap_pcalloc(r->pool, conf->bufbytes + 1);
	    dbpos = 0;
	}

	ap_hard_timeout("copy script args", r);
#ifdef SIGPIPE
	handler = signal(SIGPIPE, SIG_IGN);
#endif

	while ((len_read =
		ap_get_client_block(r, argsbuffer, HUGE_STRING_LEN)) > 0) {
	    if (conf->logname) {
		if ((dbpos + len_read) > conf->bufbytes) {
		    dbsize = conf->bufbytes - dbpos;
		}
		else {
		    dbsize = len_read;
		}
		memcpy(dbuf + dbpos, argsbuffer, dbsize);
		dbpos += dbsize;
	    }
	    ap_reset_timeout(r);
	    if (ap_bwrite(script_out, argsbuffer, len_read) < len_read) {
		/* silly script stopped reading, soak up remaining message */
		while (ap_get_client_block(r, argsbuffer, HUGE_STRING_LEN) > 0) {
		    /* dump it */
		}
		break;
	    }
	}

	ap_bflush(script_out);
	signal(SIGPIPE, handler);

	ap_kill_timeout(r);
    }

    ap_bclose(script_out);

    /* Handle script return... */
    if (script_in && !nph) {
	const char *location;
	char sbuf[MAX_STRING_LEN];
	int ret;

	if ((ret = ap_scan_script_header_err_buff(r, script_in, sbuf))) {
	    return log_script(r, conf, ret, dbuf, sbuf, script_in, script_err);
	}

#ifdef CHARSET_EBCDIC
        /* Now check the Content-Type to decide if conversion is needed */
        ap_checkconv(r);
#endif /*CHARSET_EBCDIC*/

	location = ap_table_get(r->headers_out, "Location");

	if (location && location[0] == '/' && r->status == 200) {

	    /* Soak up all the script output */
	    ap_hard_timeout("read from script", r);
	    while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_in) > 0) {
		continue;
	    }
	    while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0) {
		continue;
	    }
	    ap_kill_timeout(r);


	    /* This redirect needs to be a GET no matter what the original
	     * method was.
	     */
	    r->method = ap_pstrdup(r->pool, "GET");
	    r->method_number = M_GET;

	    /* We already read the message body (if any), so don't allow
	     * the redirected request to think it has one.  We can ignore 
	     * Transfer-Encoding, since we used REQUEST_CHUNKED_ERROR.
	     */
	    ap_table_unset(r->headers_in, "Content-Length");

	    ap_internal_redirect_handler(location, r);
	    return OK;
	}
	else if (location && r->status == 200) {
	    /* XX Note that if a script wants to produce its own Redirect
	     * body, it now has to explicitly *say* "Status: 302"
	     */
	    return REDIRECT;
	}

	ap_send_http_header(r);
	if (!r->header_only) {
	    ap_send_fb(script_in, r);
	}
	ap_bclose(script_in);

	ap_soft_timeout("soaking script stderr", r);
	while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0) {
	    continue;
	}
	ap_kill_timeout(r);
	ap_bclose(script_err);
    }

    if (script_in && nph) {
	ap_send_fb(script_in, r);
    }

    return OK;			/* NOT r->status, even if it has changed. */
}

static const handler_rec cgi_handlers[] =
{
    {CGI_MAGIC_TYPE, cgi_handler},
    {"cgi-script", cgi_handler},
    {NULL}
};

module MODULE_VAR_EXPORT cgi_module =
{
    STANDARD_MODULE_STUFF,
    NULL,			/* initializer */
    NULL,			/* dir config creater */
    NULL,			/* dir merger --- default is to override */
    create_cgi_config,		/* server config */
    merge_cgi_config,		/* merge server config */
    cgi_cmds,			/* command table */
    cgi_handlers,		/* handlers */
    NULL,			/* filename translation */
    NULL,			/* check_user_id */
    NULL,			/* check auth */
    NULL,			/* check access */
    NULL,			/* type_checker */
    NULL,			/* fixups */
    NULL,			/* logger */
    NULL,			/* header parser */
    NULL,			/* child_init */
    NULL,			/* child_exit */
    NULL			/* post read-request */
};