/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * mod_isapi.c - Internet Server Application (ISA) module for Apache
 * by Alexei Kosut <akosut@apache.org>
 *
 * This module implements Microsoft's ISAPI, allowing Apache (when running
 * under Windows) to load Internet Server Applications (ISAPI extensions).
 * It implements all of the ISAPI 2.0 specification, except for the 
 * "Microsoft-only" extensions dealing with asynchronous I/O. All ISAPI
 * extensions that use only synchronous I/O and are compatible with the
 * ISAPI 2.0 specification should work (most ISAPI 1.0 extensions should
 * function as well).
 *
 * To load, simply place the ISA in a location in the document tree.
 * Then add an "AddHandler isapi-isa dll" into your config file.
 * You should now be able to load ISAPI DLLs just be reffering to their
 * URLs. Make sure the ExecCGI option is active in the directory
 * the ISA is in.
 */

#include "apr_strings.h"
#include "apr_portable.h"
#include "apr_buckets.h"
#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_request.h"
#include "http_log.h"
#include "util_script.h"
#include "mod_core.h"

/* We use the exact same header file as the original */
#include <HttpExt.h>

#if !defined(HSE_REQ_MAP_URL_TO_PATH_EX) \
 || !defined(HSE_REQ_SEND_RESPONSE_HEADER_EX)
#pragma message("WARNING: This build of Apache is missing the recent changes")
#pragma message("in the Microsoft Win32 Platform SDK; some mod_isapi features")
#pragma message("will be disabled.  To obtain the latest Platform SDK files,")
#pragma message("please refer to:")
#pragma message("http://msdn.microsoft.com/downloads/sdks/platform/platform.asp")
#endif

/* TODO: Unknown errors that must be researched for correct codes */

#define TODO_ERROR 1

/* Seems IIS does not enforce the requirement for \r\n termination on HSE_REQ_SEND_RESPONSE_HEADER,
   define this to conform */
#define RELAX_HEADER_RULE

module AP_MODULE_DECLARE_DATA isapi_module;

/* Declare the ISAPI functions */

BOOL WINAPI GetServerVariable (HCONN hConn, LPSTR lpszVariableName,
                               LPVOID lpvBuffer, LPDWORD lpdwSizeofBuffer);
BOOL WINAPI WriteClient (HCONN ConnID, LPVOID Buffer, LPDWORD lpdwBytes,
                         DWORD dwReserved);
BOOL WINAPI ReadClient (HCONN ConnID, LPVOID lpvBuffer, LPDWORD lpdwSize);
BOOL WINAPI ServerSupportFunction (HCONN hConn, DWORD dwHSERequest,
                                   LPVOID lpvBuffer, LPDWORD lpdwSize,
                                   LPDWORD lpdwDataType);

/*
    The optimiser blows it totally here. What happens is that autos are addressed relative to the
    stack pointer, which, of course, moves around. The optimiser seems to lose track of it somewhere
    between setting HttpExtensionProc's address and calling through it. We work around the problem by 
    forcing it to use frame pointers.

    The revisions below may eliminate this artifact.
*/
#pragma optimize("y",off)

/* Our isapi server config structure */

typedef struct {
    apr_array_header_t *loaded;
    DWORD ReadAheadBuffer;
    int LogNotSupported;
    int AppendLogToErrors;
    int AppendLogToQuery;
} isapi_server_conf;

/* Our loaded isapi module description structure */

typedef struct {
    const char *filename;
    apr_dso_handle_t *handle;
    HSE_VERSION_INFO *pVer;
    PFN_GETEXTENSIONVERSION GetExtensionVersion;
    PFN_HTTPEXTENSIONPROC   HttpExtensionProc;
    PFN_TERMINATEEXTENSION  TerminateExtension;
    int   refcount;
    DWORD timeout;
    BOOL  fakeasync;
    DWORD reportversion;
} isapi_loaded;

/* Our "Connection ID" structure */

typedef struct {
    LPEXTENSION_CONTROL_BLOCK ecb;
    isapi_server_conf *sconf;
    isapi_loaded *isa;
    request_rec  *r;
    PFN_HSE_IO_COMPLETION completion;
    PVOID  completion_arg;
    HANDLE complete;
} isapi_cid;

static void *create_isapi_server_config(apr_pool_t *p, server_rec *s)
{
    isapi_server_conf *sconf = apr_palloc(p, sizeof(isapi_server_conf));
    sconf->loaded = apr_array_make(p, 20, sizeof(isapi_loaded*));
    
    sconf->ReadAheadBuffer = 49152;
    sconf->LogNotSupported    = -1;
    sconf->AppendLogToErrors   = 0;
    sconf->AppendLogToQuery    = 0;

    return sconf;
}

static int compare_loaded(const void *av, const void *bv)
{
    const isapi_loaded **a = av;
    const isapi_loaded **b = bv;

    return strcmp((*a)->filename, (*b)->filename);
}

static int isapi_post_config(apr_pool_t *p, apr_pool_t *plog,
                             apr_pool_t *ptemp, server_rec *s)
{
    isapi_server_conf *sconf = ap_get_module_config(s->module_config, 
                                                    &isapi_module);
    isapi_loaded **elts = (isapi_loaded **)sconf->loaded->elts;
    int nelts = sconf->loaded->nelts;

    /* sort the elements of the main_server, by filename */
    qsort(elts, nelts, sizeof(isapi_loaded*), compare_loaded);

    /* and make all virtualhosts share the same */
    for (s = s->next; s; s = s->next) {
	ap_set_module_config(s->module_config, &isapi_module, sconf);
    }
    return OK;
}

static apr_status_t isapi_unload(isapi_loaded* isa, int force);

static apr_status_t cleanup_isapi(void *isa)
{
    return isapi_unload((isapi_loaded*) isa, TRUE);
}

static apr_status_t isapi_load(apr_pool_t *p, isapi_server_conf *sconf, 
                               request_rec *r, const char *fpath, 
                               isapi_loaded** isa)
{
    isapi_loaded **found = (isapi_loaded **)sconf->loaded->elts;
    apr_status_t rv;
    int n;

    for (n = 0; n < sconf->loaded->nelts; ++n) {
        if (strcasecmp(fpath, (*found)->filename) == 0) {
            break;
        }
        ++found;
    }
    
    if (n < sconf->loaded->nelts) 
    {
        *isa = *found;
        if ((*isa)->handle) 
        {
            ++(*isa)->refcount;
            return APR_SUCCESS;
        }
        /* Otherwise we fall through and have to reload the resource
         * into this existing mod_isapi cache bucket.
         */
    }
    else
    {
        *isa = apr_pcalloc(p, sizeof(isapi_module));
        (*isa)->filename = fpath;
        (*isa)->pVer = apr_pcalloc(p, sizeof(HSE_VERSION_INFO));
    
        /* TODO: These need to become overrideable, so that we
         * assure a given isapi can be fooled into behaving well.
         */
        (*isa)->timeout = INFINITE; /* microsecs */
        (*isa)->fakeasync = TRUE;
        (*isa)->reportversion = MAKELONG(0, 5); /* Revision 5.0 */
    }
    
    rv = apr_dso_load(&(*isa)->handle, fpath, p);
    if (rv)
    {
        ap_log_rerror(APLOG_MARK, APLOG_ALERT, rv, r,
                      "ISAPI %s failed to load", fpath);
        (*isa)->handle = NULL;
        return rv;
    }

    rv = apr_dso_sym((void**)&(*isa)->GetExtensionVersion, (*isa)->handle,
                     "GetExtensionVersion");
    if (rv)
    {
        ap_log_rerror(APLOG_MARK, APLOG_ALERT, rv, r,
                      "ISAPI %s is missing GetExtensionVersion()",
                      fpath);
        apr_dso_unload((*isa)->handle);
        (*isa)->handle = NULL;
        return rv;
    }

    rv = apr_dso_sym((void**)&(*isa)->HttpExtensionProc, (*isa)->handle,
                     "HttpExtensionProc");
    if (rv)
    {
        ap_log_rerror(APLOG_MARK, APLOG_ALERT, rv, r,
                      "ISAPI %s is missing HttpExtensionProc()",
                      fpath);
        apr_dso_unload((*isa)->handle);
        (*isa)->handle = NULL;
        return rv;
    }

    /* TerminateExtension() is an optional interface */
    rv = apr_dso_sym((void**)&(*isa)->TerminateExtension, (*isa)->handle,
                     "TerminateExtension");
    SetLastError(0);

    /* Run GetExtensionVersion() */
    if (!((*isa)->GetExtensionVersion)((*isa)->pVer)) {
        apr_status_t rv = apr_get_os_error();
        ap_log_rerror(APLOG_MARK, APLOG_ALERT, rv, r,
                      "ISAPI %s call GetExtensionVersion() failed", 
                      fpath);
        apr_dso_unload((*isa)->handle);
        (*isa)->handle = NULL;
        return rv;
    }

    ++(*isa)->refcount;

    apr_pool_cleanup_register(p, *isa, cleanup_isapi, 
                                   apr_pool_cleanup_null);

    return APR_SUCCESS;
}

static apr_status_t isapi_unload(isapi_loaded* isa, int force)
{
    /* All done with the DLL... get rid of it...
     *
     * If optionally cached, pass HSE_TERM_ADVISORY_UNLOAD,
     * and if it returns TRUE, unload, otherwise, cache it.
     */
    if (((--isa->refcount > 0) && !force) || !isa->handle)
        return APR_SUCCESS;
    if (isa->TerminateExtension) {
        if (force)
            (*isa->TerminateExtension)(HSE_TERM_MUST_UNLOAD);
        else if (!(*isa->TerminateExtension)(HSE_TERM_ADVISORY_UNLOAD))
            return APR_EGENERAL;
    }
    apr_dso_unload(isa->handle);
    isa->handle = NULL;
    return APR_SUCCESS;
}

apr_status_t isapi_handler (request_rec *r)
{
    isapi_server_conf * sconf;
    apr_table_t *e;
    apr_status_t rv;
    isapi_loaded *isa;
    isapi_cid *cid;
    const char *val;
    DWORD read;
    int res;
    
    if(strcmp(r->handler, "isapi-isa"))
        return DECLINED;    

    sconf = ap_get_module_config(r->server->module_config, &isapi_module);
    e = r->subprocess_env;

    /* Use similar restrictions as CGIs
     *
     * If this fails, it's pointless to load the isapi dll.
     */
    if (!(ap_allow_options(r) & OPT_EXECCGI))
        return HTTP_FORBIDDEN;

    if (r->finfo.filetype == APR_NOFILE)
        return HTTP_NOT_FOUND;

    if (r->finfo.filetype != APR_REG)
        return HTTP_FORBIDDEN;

    if (r->path_info && *r->path_info && !r->used_path_info)
        return HTTP_NOT_FOUND;

    /* Load the isapi extention without caching (sconf == NULL) 
     * but note that we will recover an existing cached module.
     */
    if (isapi_load(r->pool, sconf, r, r->filename, &isa) != APR_SUCCESS)
        return HTTP_INTERNAL_SERVER_ERROR;
        
    /* Set up variables */
    ap_add_common_vars(r);
    ap_add_cgi_vars(r);
    apr_table_setn(e, "UNMAPPED_REMOTE_USER", "REMOTE_USER");
    if ((val = apr_table_get(e, "HTTPS")) && strcmp(val, "on"))
        apr_table_setn(e, "SERVER_PORT_SECURE", "1");
    else
        apr_table_setn(e, "SERVER_PORT_SECURE", "0");
    apr_table_setn(e, "URL", r->uri);

    /* Set up connection structure and ecb */
    cid = apr_pcalloc(r->pool, sizeof(isapi_cid));
    cid->sconf = ap_get_module_config(r->server->module_config, &isapi_module);

    cid->ecb = apr_pcalloc(r->pool, sizeof(struct _EXTENSION_CONTROL_BLOCK));
    cid->ecb->ConnID = (HCONN)cid;
    cid->isa = isa;
    cid->r = r;
    cid->r->status = 0;
    cid->complete = NULL;
    cid->completion = NULL;
    
    cid->ecb->cbSize = sizeof(EXTENSION_CONTROL_BLOCK);
    cid->ecb->dwVersion = isa->reportversion;
    cid->ecb->dwHttpStatusCode = 0;
    strcpy(cid->ecb->lpszLogData, "");
    // TODO: are copies really needed here?
    cid->ecb->lpszMethod = apr_pstrdup(r->pool, (char*) r->method);
    cid->ecb->lpszQueryString = apr_pstrdup(r->pool, 
                                (char*) apr_table_get(e, "QUERY_STRING"));
    cid->ecb->lpszPathInfo = apr_pstrdup(r->pool, 
                             (char*) apr_table_get(e, "PATH_INFO"));
    cid->ecb->lpszPathTranslated = apr_pstrdup(r->pool, 
                                   (char*) apr_table_get(e, "PATH_TRANSLATED"));
    cid->ecb->lpszContentType = apr_pstrdup(r->pool, 
                                (char*) apr_table_get(e, "CONTENT_TYPE"));
    /* Set up the callbacks */
    cid->ecb->GetServerVariable = GetServerVariable;
    cid->ecb->WriteClient = WriteClient;
    cid->ecb->ReadClient = ReadClient;
    cid->ecb->ServerSupportFunction = ServerSupportFunction;

    
    /* Set up client input */
    res = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR);
    if (res) {
        isapi_unload(isa, FALSE);
        return res;
    }

    if (ap_should_client_block(r)) {
        /* Time to start reading the appropriate amount of data,
         * and allow the administrator to tweak the number
         * TODO: add the httpd.conf option for ReadAheadBuffer.
         */
        if (r->remaining) {
            cid->ecb->cbTotalBytes = (apr_size_t)r->remaining;
            if (cid->ecb->cbTotalBytes > cid->sconf->ReadAheadBuffer)
                cid->ecb->cbAvailable = cid->sconf->ReadAheadBuffer;
            else
                cid->ecb->cbAvailable = cid->ecb->cbTotalBytes;
        }
        else
        {
            cid->ecb->cbTotalBytes = 0xffffffff;
            cid->ecb->cbAvailable = cid->sconf->ReadAheadBuffer;
        }

        cid->ecb->lpbData = apr_pcalloc(r->pool, cid->ecb->cbAvailable + 1);

        read = 0;
        while (read < cid->ecb->cbAvailable &&
               ((res = ap_get_client_block(r, cid->ecb->lpbData + read,
                                        cid->ecb->cbAvailable - read)) > 0)) {
            read += res;
        }

        if (res < 0) {
            isapi_unload(isa, FALSE);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* Although it's not to spec, IIS seems to null-terminate
         * its lpdData string. So we will too.
         */
        if (res == 0)
            cid->ecb->cbAvailable = cid->ecb->cbTotalBytes = read;
        else
            cid->ecb->cbAvailable = read;
        cid->ecb->lpbData[read] = '\0';
    }
    else {
        cid->ecb->cbTotalBytes = 0;
        cid->ecb->cbAvailable = 0;
        cid->ecb->lpbData = NULL;
    }

    /* All right... try and run the sucker */
    rv = (*isa->HttpExtensionProc)(cid->ecb);

    /* Check for a log message - and log it */
    if (cid->ecb->lpszLogData && *cid->ecb->lpszLogData)
        ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, r,
                      "ISAPI %s: %s", r->filename, cid->ecb->lpszLogData);

    switch(rv) {
        case 0:  /* Strange, but MS isapi accepts this as success */
        case HSE_STATUS_SUCCESS:
        case HSE_STATUS_SUCCESS_AND_KEEP_CONN:
            /* Ignore the keepalive stuff; Apache handles it just fine without
             * the ISA's "advice".
             * Per Microsoft: "In IIS versions 4.0 and later, the return
             * values HSE_STATUS_SUCCESS and HSE_STATUS_SUCCESS_AND_KEEP_CONN
             * are functionally identical: Keep-Alive connections are
             * maintained, if supported by the client."
             * ... so we were pat all this time
             */
            break;

        case HSE_STATUS_PENDING:    
            /* emulating async behavior...
             *
             * Create a cid->completed event and wait on it for some timeout
             * so that the app thinks is it running async.
             *
             * All async ServerSupportFunction calls will be handled through
             * the registered IO_COMPLETION hook.
             */
            
            if (!isa->fakeasync) {
                if (cid->sconf->LogNotSupported)
                {
                     ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                                   "ISAPI %s asynch I/O request refused", 
                                   r->filename);
                     cid->r->status = HTTP_INTERNAL_SERVER_ERROR;
                }
            }
            else {
                cid->complete = CreateEvent(NULL, FALSE, FALSE, NULL);
                if (WaitForSingleObject(cid->complete, isa->timeout)
                        == WAIT_TIMEOUT) {
                    /* TODO: Now what... if this hung, then do we kill our own
                     * thread to force its death?  For now leave timeout = -1
                     */
                }
            }
            break;

        case HSE_STATUS_ERROR:    
            /* end response if we have yet to do so.
             */
            cid->r->status = HTTP_INTERNAL_SERVER_ERROR;
            break;

        default:
            /* TODO: log unrecognized retval for debugging 
             */
            cid->r->status = HTTP_INTERNAL_SERVER_ERROR;
            break;
    }

    /* Set the status (for logging) */
    if (cid->ecb->dwHttpStatusCode) {
        cid->r->status = cid->ecb->dwHttpStatusCode;
    }

    /* All done with the DLL... get rid of it... */
    isapi_unload(isa, FALSE);
    
    return OK;		/* NOT r->status, even if it has changed. */
}
#pragma optimize("",on)

BOOL WINAPI GetServerVariable (HCONN hConn, LPSTR lpszVariableName,
                               LPVOID lpvBuffer, LPDWORD lpdwSizeofBuffer)
{
    request_rec *r = ((isapi_cid *)hConn)->r;
    const char *result;
    DWORD len;

    if (!strcmp(lpszVariableName, "ALL_HTTP")) 
    {
        /* lf delimited, colon split, comma seperated and 
         * null terminated list of HTTP_ vars 
         */
        const apr_array_header_t *arr = apr_table_elts(r->subprocess_env);
        const apr_table_entry_t *elts = (const apr_table_entry_t *)arr->elts;
        int i;

        for (len = 0, i = 0; i < arr->nelts; i++) {
            if (!strncmp(elts[i].key, "HTTP_", 5)) {
                len += strlen(elts[i].key) + strlen(elts[i].val) + 2;
            }
        }
  
        if (*lpdwSizeofBuffer < len + 1) {
            *lpdwSizeofBuffer = len + 1;
            SetLastError(ERROR_INSUFFICIENT_BUFFER);
            return FALSE;
        }
    
        for (i = 0; i < arr->nelts; i++) {
            if (!strncmp(elts[i].key, "HTTP_", 5)) {
                strcpy(lpvBuffer, elts[i].key);
                ((char*)lpvBuffer) += strlen(elts[i].key);
                *(((char*)lpvBuffer)++) = ':';
                strcpy(lpvBuffer, elts[i].val);
                ((char*)lpvBuffer) += strlen(elts[i].val);
                *(((char*)lpvBuffer)++) = '\n';
            }
        }

        *(((char*)lpvBuffer)++) = '\0';
        *lpdwSizeofBuffer = len;
        return TRUE;
    }
    
    if (!strcmp(lpszVariableName, "ALL_RAW")) 
    {
        /* lf delimited, colon split, comma seperated and 
         * null terminated list of the raw request header
         */
        const apr_array_header_t *arr = apr_table_elts(r->headers_in);
        const apr_table_entry_t *elts = (const apr_table_entry_t *)arr->elts;
        int i;

        for (len = 0, i = 0; i < arr->nelts; i++) {
            len += strlen(elts[i].key) + strlen(elts[i].val) + 2;
        }
  
        if (*lpdwSizeofBuffer < len + 1) {
            *lpdwSizeofBuffer = len + 1;
            SetLastError(ERROR_INSUFFICIENT_BUFFER);
            return FALSE;
        }
    
        for (i = 0; i < arr->nelts; i++) {
            strcpy(lpvBuffer, elts[i].key);
            ((char*)lpvBuffer) += strlen(elts[i].key);
            *(((char*)lpvBuffer)++) = ':';
            *(((char*)lpvBuffer)++) = ' ';
            strcpy(lpvBuffer, elts[i].val);
            ((char*)lpvBuffer) += strlen(elts[i].val);
            *(((char*)lpvBuffer)++) = '\n';
        }
        *(((char*)lpvBuffer)++) = '\0';
        *lpdwSizeofBuffer = len;
        return TRUE;
    }
    
    /* Not a special case */
    result = apr_table_get(r->subprocess_env, lpszVariableName);

    if (result) {
        len = strlen(result);
        if (*lpdwSizeofBuffer < len + 1) {
            *lpdwSizeofBuffer = len + 1;
            SetLastError(ERROR_INSUFFICIENT_BUFFER);
            return FALSE;
        }
        strcpy(lpvBuffer, result);
        *lpdwSizeofBuffer = len;
        return TRUE;
    }

    /* Not Found */
    SetLastError(ERROR_INVALID_INDEX);
    return FALSE;
}

BOOL WINAPI WriteClient (HCONN ConnID, LPVOID Buffer, LPDWORD lpdwBytes,
                         DWORD dwReserved)
{
    request_rec *r = ((isapi_cid *)ConnID)->r;
    apr_bucket_brigade *bb;
    apr_bucket *b;

    if (dwReserved == HSE_IO_SYNC)
        ; /* XXX: Fake it */

    bb = apr_brigade_create(r->pool);
    b = apr_bucket_transient_create(Buffer, *lpdwBytes);
    APR_BRIGADE_INSERT_TAIL(bb, b);
    b = apr_bucket_flush_create();
    APR_BRIGADE_INSERT_TAIL(bb, b);
    ap_pass_brigade(r->output_filters, bb);

    return TRUE;
}

BOOL WINAPI ReadClient (HCONN ConnID, LPVOID lpvBuffer, LPDWORD lpdwSize)
{
    request_rec *r = ((isapi_cid *)ConnID)->r;
    DWORD read = 0;
    int res;

    if (r->remaining < *lpdwSize) {
        *lpdwSize = (apr_size_t)r->remaining;
    }

    while (read < *lpdwSize &&
           ((res = ap_get_client_block(r, (char*)lpvBuffer + read,
                                       *lpdwSize - read)) > 0)) {
        read += res;
    }

    *lpdwSize = read;
    return TRUE;
}

static apr_ssize_t SendResponseHeaderEx(isapi_cid *cid, const char *stat,
                                        const char *head, apr_size_t statlen,
                                        apr_size_t headlen)
{
    int termarg;
    char *termch;

    if (!stat || statlen == 0 || !*stat) {
        stat = "Status: 200 OK";
    }
    else {
        char *newstat;
        newstat = apr_palloc(cid->r->pool, statlen + 9);
        strcpy(newstat, "Status: ");
        apr_cpystrn(newstat + 8, stat, statlen + 1);
        stat = newstat;
    }

    if (!head || headlen == 0 || !*head) {
        head = "\r\n";
    }
    else
    {
        if (head[headlen]) {
            /* Whoops... not NULL terminated */
            head = apr_pstrndup(cid->r->pool, head, headlen);
        }
    }
 
    /* Parse them out, or die trying */
    cid->r->status= ap_scan_script_header_err_strs(cid->r, NULL, &termch,
                                                  &termarg, stat, head, NULL);
    cid->ecb->dwHttpStatusCode = cid->r->status;
    if (cid->r->status == HTTP_INTERNAL_SERVER_ERROR)
        return -1;
    
    /* Headers will actually go when they are good and ready */

    /* If all went well, tell the caller we consumed the headers complete */
    if (!termch)
        return(headlen);

    /* Any data left is sent directly by the caller, all we
     * give back is the size of the headers we consumed
     */
    if (termch && (termarg == 1) && head + headlen > termch) {
        return termch - head;
    }
    return 0;
}

BOOL WINAPI ServerSupportFunction(HCONN hConn, DWORD dwHSERequest,
                                  LPVOID lpvBuffer, LPDWORD lpdwSize,
                                  LPDWORD lpdwDataType)
{
    isapi_cid *cid = (isapi_cid *)hConn;
    request_rec *r = cid->r;
    request_rec *subreq;

    switch (dwHSERequest) {
    case 1: /* HSE_REQ_SEND_URL_REDIRECT_RESP */
        /* Set the status to be returned when the HttpExtensionProc()
         * is done.
         * WARNING: Microsoft now advertises HSE_REQ_SEND_URL_REDIRECT_RESP
         *          and HSE_REQ_SEND_URL as equivalant per the Jan 2000 SDK.
         *          They most definately are not, even in their own samples.
         */
        apr_table_set (r->headers_out, "Location", lpvBuffer);
        cid->r->status = cid->ecb->dwHttpStatusCode 
                                               = HTTP_MOVED_TEMPORARILY;
        return TRUE;

    case 2: /* HSE_REQ_SEND_URL */
        /* Soak up remaining input */
        if (r->remaining > 0) {
            char argsbuffer[HUGE_STRING_LEN];
            while (ap_get_client_block(r, argsbuffer, HUGE_STRING_LEN));
        }

        /* Reset the method to GET */
        r->method = apr_pstrdup(r->pool, "GET");
        r->method_number = M_GET;

        /* Don't let anyone think there's still data */
        apr_table_unset(r->headers_in, "Content-Length");

        /* AV fault per PR3598 - redirected path is lost! */
        (char*)lpvBuffer = apr_pstrdup(r->pool, (char*)lpvBuffer);
        ap_internal_redirect((char*)lpvBuffer, r);
        return TRUE;

    case 3: /* HSE_REQ_SEND_RESPONSE_HEADER */
    {
        /* Parse them out, or die trying */
        apr_size_t statlen = 0, headlen = 0;
        apr_ssize_t ate;
        if (lpvBuffer)
            statlen = strlen((char*) lpvBuffer);
        if (lpdwDataType)
            headlen = strlen((char*) lpdwDataType);
        ate = SendResponseHeaderEx(cid, (char*) lpvBuffer,
                                   (char*) lpdwDataType,
                                   statlen, headlen);
        if (ate < 0) {
            SetLastError(TODO_ERROR);
            return FALSE;
        }
        else if ((apr_size_t)ate < headlen) {
            apr_bucket_brigade *bb;
            apr_bucket *b;
            bb = apr_brigade_create(cid->r->pool);
	    b = apr_bucket_transient_create((char*) lpdwDataType + ate, 
                                           headlen - ate);
	    APR_BRIGADE_INSERT_TAIL(bb, b);
            b = apr_bucket_flush_create();
	    APR_BRIGADE_INSERT_TAIL(bb, b);
	    ap_pass_brigade(cid->r->output_filters, bb);
        }
        return TRUE;
    }

    case 4: /* HSE_REQ_DONE_WITH_SESSION */
        /* Signal to resume the thread completing this request
         */
        if (cid->complete)
            SetEvent(cid->complete);            
        return TRUE;

    case 1001: /* HSE_REQ_MAP_URL_TO_PATH */
    {
        /* Map a URL to a filename */
        char *file = (char *)lpvBuffer;
        DWORD len;
        subreq = ap_sub_req_lookup_uri(apr_pstrndup(r->pool, file, *lpdwSize),
                                       r, NULL);

        len = apr_cpystrn(file, subreq->filename, *lpdwSize) - file;


        /* IIS puts a trailing slash on directories, Apache doesn't */
        if (subreq->finfo.filetype == APR_DIR) {
            if (len < *lpdwSize - 1) {
                file[len++] = '\\';
                file[len] = '\0';
            }
        }
        *lpdwSize = len;
        return TRUE;
    }

    case 1002: /* HSE_REQ_GET_SSPI_INFO */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                           "ISAPI ServerSupportFunction HSE_REQ_GET_SSPI_INFO "
                           "is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
        
    case 1003: /* HSE_APPEND_LOG_PARAMETER */
        /* Log lpvBuffer, of lpdwSize bytes, in the URI Query (cs-uri-query) field
         */
        apr_table_set(r->notes, "isapi-parameter", (char*) lpvBuffer);
        if (cid->sconf->AppendLogToQuery) {
            if (r->args)
                r->args = apr_pstrcat(r->pool, r->args, (char*) lpvBuffer, NULL);
            else
                r->args = apr_pstrdup(r->pool, (char*) lpvBuffer);
        }
        if (cid->sconf->AppendLogToErrors)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, r,
                          "ISAPI %s: %s", cid->r->filename,
                          (char*) lpvBuffer);
        return TRUE;
        
    case 1005: /* HSE_REQ_IO_COMPLETION */
        /* Emulates a completion port...  Record callback address and 
         * user defined arg, we will call this after any async request 
         * (e.g. transmitfile) as if the request executed async.
         * Per MS docs... HSE_REQ_IO_COMPLETION replaces any prior call
         * to HSE_REQ_IO_COMPLETION, and lpvBuffer may be set to NULL.
         */
        if (!cid->isa->fakeasync) {
            if (cid->sconf->LogNotSupported)
                ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction HSE_REQ_IO_COMPLETION "
                          "is not supported: %s", r->filename);
            SetLastError(ERROR_INVALID_PARAMETER);
            return FALSE;
        }
        cid->completion = (PFN_HSE_IO_COMPLETION) lpvBuffer;
        cid->completion_arg = (PVOID) lpdwDataType;
        return TRUE;

    case 1006: /* HSE_REQ_TRANSMIT_FILE */
    {
        HSE_TF_INFO *tf = (HSE_TF_INFO*)lpvBuffer;
        apr_status_t rv;
        apr_bucket_brigade *bb;
        apr_bucket *b;
        apr_file_t *fd;

        if (!cid->isa->fakeasync && (tf->dwFlags & HSE_IO_ASYNC)) {
            if (cid->sconf->LogNotSupported)
                ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                         "ISAPI ServerSupportFunction HSE_REQ_TRANSMIT_FILE "
                         "as HSE_IO_ASYNC is not supported: %s", r->filename);
            SetLastError(ERROR_INVALID_PARAMETER);
            return FALSE;
        }
        
        if ((rv = apr_os_file_put(&fd, tf->hFile, 0, r->pool)) != APR_SUCCESS) {
            return FALSE;
        }
        
        /* apr_dupfile_oshandle (&fd, tf->hFile, r->pool); */
        bb = apr_brigade_create(r->pool);

        if (tf->dwFlags & HSE_IO_SEND_HEADERS) 
        {
            /* According to MS: if calling HSE_REQ_TRANSMIT_FILE with the
             * HSE_IO_SEND_HEADERS flag, then you can't otherwise call any
             * HSE_SEND_RESPONSE_HEADERS* fn, but if you don't use the flag,
             * you must have done so.  They document that the pHead headers
             * option is valid only for HSE_IO_SEND_HEADERS - we are a bit
             * more flexible and assume with the flag, pHead are the
             * response headers, and without, pHead simply contains text
             * (handled after this case).
             */
            apr_ssize_t ate = SendResponseHeaderEx(cid, tf->pszStatusCode, 
                                                   (char*)tf->pHead,
                                                   strlen(tf->pszStatusCode), 
                                                   tf->HeadLength);
            if (ate < 0)
            {
                apr_brigade_destroy(bb);
                SetLastError(TODO_ERROR);
                return FALSE;
            }
            if ((apr_size_t)ate < tf->HeadLength)
            {
                b = apr_bucket_transient_create((char*)tf->pHead + ate, 
                                                tf->HeadLength - ate);
                APR_BRIGADE_INSERT_TAIL(bb, b);
            }
        }
        else if (tf->pHead && tf->HeadLength) {
            b = apr_bucket_transient_create((char*)tf->pHead, 
                                            tf->HeadLength);
            APR_BRIGADE_INSERT_TAIL(bb, b);
        }

        b = apr_bucket_file_create(fd, tf->Offset, 
                                   tf->BytesToWrite, r->pool);
        APR_BRIGADE_INSERT_TAIL(bb, b);
        
        if (tf->pTail && tf->TailLength) {
            b = apr_bucket_transient_create((char*)tf->pTail, 
                                            tf->TailLength);
            APR_BRIGADE_INSERT_TAIL(bb, b);
        }
        
        b = apr_bucket_flush_create();
        APR_BRIGADE_INSERT_TAIL(bb, b);
        ap_pass_brigade(r->output_filters, bb);

        /* we do nothing with (tf->dwFlags & HSE_DISCONNECT_AFTER_SEND)
         */

        if (tf->dwFlags & HSE_IO_ASYNC) {
            /* XXX: Fake async response,
             * use tf->pfnHseIO, or if NULL, then use cid->fnIOComplete
             * pass pContect to the HseIO callback.
             */
        }
        return TRUE;
    }

    case 1007: /* HSE_REQ_REFRESH_ISAPI_ACL */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction "
                          "HSE_REQ_REFRESH_ISAPI_ACL "
                          "is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

    case 1008: /* HSE_REQ_IS_KEEP_CONN */
        *((LPBOOL) lpvBuffer) = (r->connection->keepalive == 1);
        return TRUE;

    case 1010: /* XXX: Fake it : HSE_REQ_ASYNC_READ_CLIENT */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI asynchronous I/O not supported: %s", 
                          r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

    case 1011: /* HSE_REQ_GET_IMPERSONATION_TOKEN  Added in ISAPI 4.0 */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction "
                          "HSE_REQ_GET_IMPERSONATION_TOKEN "
                          "is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

#ifdef HSE_REQ_MAP_URL_TO_PATH_EX
    case 1012: /* HSE_REQ_MAP_URL_TO_PATH_EX */
    {
        /* Map a URL to a filename */
        LPHSE_URL_MAPEX_INFO info = (LPHSE_URL_MAPEX_INFO) lpdwDataType;
        char* test_uri = apr_pstrndup(r->pool, (char *)lpvBuffer, *lpdwSize);

        subreq = ap_sub_req_lookup_uri(test_uri, r, NULL);
        info->cchMatchingURL = strlen(test_uri);        
        info->cchMatchingPath = apr_cpystrn(info->lpszPath, subreq->filename, 
                                            MAX_PATH) - info->lpszPath;

        /* Mapping started with assuming both strings matched.
         * Now roll on the path_info as a mismatch and handle
         * terminating slashes for directory matches.
         */
        if (subreq->path_info && *subreq->path_info) {
            apr_cpystrn(info->lpszPath + info->cchMatchingPath, 
                        subreq->path_info, MAX_PATH - info->cchMatchingPath);
            info->cchMatchingURL -= strlen(subreq->path_info);
            if (subreq->finfo.filetype == APR_DIR
                 && info->cchMatchingPath < MAX_PATH - 1) {
                /* roll forward over path_info's first slash */
                ++info->cchMatchingPath;
                ++info->cchMatchingURL;
            }
        }
        else if (subreq->finfo.filetype == APR_DIR
                 && info->cchMatchingPath < MAX_PATH - 1) {
            /* Add a trailing slash for directory */
            info->lpszPath[info->cchMatchingPath++] = '/';
            info->lpszPath[info->cchMatchingPath] = '\0';
        }

        /* If the matched isn't a file, roll match back to the prior slash */
        if (subreq->finfo.filetype == APR_NOFILE) {
            while (info->cchMatchingPath && info->cchMatchingURL) {
                if (info->lpszPath[info->cchMatchingPath - 1] == '/') 
                    break;
                --info->cchMatchingPath;
                --info->cchMatchingURL;
            }
        }
        
        /* Paths returned with back slashes */
        for (test_uri = info->lpszPath; *test_uri; ++test_uri)
            if (*test_uri == '/')
                *test_uri = '\\';
        
        /* is a combination of:
         * HSE_URL_FLAGS_READ         0x001 Allow read
         * HSE_URL_FLAGS_WRITE        0x002 Allow write
         * HSE_URL_FLAGS_EXECUTE      0x004 Allow execute
         * HSE_URL_FLAGS_SSL          0x008 Require SSL
         * HSE_URL_FLAGS_DONT_CACHE   0x010 Don't cache (VRoot only)
         * HSE_URL_FLAGS_NEGO_CERT    0x020 Allow client SSL cert
         * HSE_URL_FLAGS_REQUIRE_CERT 0x040 Require client SSL cert
         * HSE_URL_FLAGS_MAP_CERT     0x080 Map client SSL cert to account
         * HSE_URL_FLAGS_SSL128       0x100 Require 128-bit SSL cert
         * HSE_URL_FLAGS_SCRIPT       0x200 Allow script execution
         *
         * XxX: As everywhere, EXEC flags could use some work...
         *      and this could go further with more flags, as desired.
         */ 
        info->dwFlags = (subreq->finfo.protection & APR_UREAD    ? 0x001 : 0)
                      | (subreq->finfo.protection & APR_UWRITE   ? 0x002 : 0)
                      | (subreq->finfo.protection & APR_UEXECUTE ? 0x204 : 0);
        return TRUE;
    }
#endif

    case 1014: /* HSE_REQ_ABORTIVE_CLOSE */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction HSE_REQ_ABORTIVE_CLOSE"
                          " is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

    case 1015: /* HSE_REQ_GET_CERT_INFO_EX  Added in ISAPI 4.0 */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction "
                          "HSE_REQ_GET_CERT_INFO_EX "
                          "is not supported: %s", r->filename);        
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

#ifdef HSE_REQ_SEND_RESPONSE_HEADER_EX
    case 1016: /* HSE_REQ_SEND_RESPONSE_HEADER_EX  Added in ISAPI 4.0 */
    {
        LPHSE_SEND_HEADER_EX_INFO shi
                                  = (LPHSE_SEND_HEADER_EX_INFO) lpvBuffer;
        /* XXX: ignore shi->fKeepConn?  We shouldn't need the advise */
        /* r->connection->keepalive = shi->fKeepConn; */
        apr_ssize_t ate = SendResponseHeaderEx(cid, shi->pszStatus, 
                                               shi->pszHeader,
                                               shi->cchStatus, 
                                               shi->cchHeader);
        if (ate < 0) {
            SetLastError(TODO_ERROR);
            return FALSE;
        }
        else if ((apr_size_t)ate < shi->cchHeader) {
            apr_bucket_brigade *bb;
            apr_bucket *b;
            bb = apr_brigade_create(cid->r->pool);
	    b = apr_bucket_transient_create(shi->pszHeader + ate, 
                                            shi->cchHeader - ate);
	    APR_BRIGADE_INSERT_TAIL(bb, b);
            b = apr_bucket_flush_create();
	    APR_BRIGADE_INSERT_TAIL(bb, b);
	    ap_pass_brigade(cid->r->output_filters, bb);
        }
        return TRUE;

    }
#endif

    case 1017: /* HSE_REQ_CLOSE_CONNECTION  Added after ISAPI 4.0 */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction "
                          "HSE_REQ_CLOSE_CONNECTION "
                          "is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

    case 1018: /* HSE_REQ_IS_CONNECTED  Added after ISAPI 4.0 */
        /* Returns True if client is connected c.f. MSKB Q188346
         * assuming the identical return mechanism as HSE_REQ_IS_KEEP_CONN
         */
        *((LPBOOL) lpvBuffer) = (r->connection->aborted == 0);
        return TRUE;

    case 1020: /* HSE_REQ_EXTENSION_TRIGGER  Added after ISAPI 4.0 */
        /*  Undocumented - defined by the Microsoft Jan '00 Platform SDK
         */
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction "
                          "HSE_REQ_EXTENSION_TRIGGER "
                          "is not supported: %s", r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;

    default:
        if (cid->sconf->LogNotSupported)
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, r,
                          "ISAPI ServerSupportFunction (%d) not supported: "
                          "%s", dwHSERequest, r->filename);
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
    }
}

/*
 * Command handler for the ISAPIReadAheadBuffer directive, which is TAKE1
 */
static const char *isapi_cmd_readaheadbuffer(cmd_parms *cmd, void *config, 
                                             char *arg)
{
    isapi_server_conf *sconf = ap_get_module_config(cmd->server->module_config,
                                                   &isapi_module);
    char *scan;
    long val;

    if (((val = strtol(arg, (char **) &scan, 10)) <= 0) || *scan)
        return "ISAPIReadAheadBuffer must be a legitimate value.";
    
    sconf->ReadAheadBuffer = val;
    return NULL;
}

/*
 * Command handler for the ISAPIReadAheadBuffer directive, which is TAKE1
 */
static const char *isapi_cmd_lognotsupported(cmd_parms *cmd, void *config, 
                                             char *arg)
{
    isapi_server_conf *sconf = ap_get_module_config(cmd->server->module_config,
                                               &isapi_module);

    if (strcasecmp(arg, "on") == 0) {
        sconf->LogNotSupported = -1;
    }
    else if (strcasecmp(arg, "off") == 0) {
        sconf->LogNotSupported = 0;
    }
    else {
        return "ISAPILogNotSupported must be on or off";
    }
    return NULL;
}

static const char *isapi_cmd_appendlogtoerrors(cmd_parms *cmd, void *config, 
                                               char *arg)
{
    isapi_server_conf *sconf = ap_get_module_config(cmd->server->module_config,
                                                   &isapi_module);

    if (strcasecmp(arg, "on") == 0) {
        sconf->AppendLogToErrors = -1;
    }
    else if (strcasecmp(arg, "off") == 0) {
        sconf->AppendLogToErrors = 0;
    }
    else {
        return "ISAPIAppendLogToErrors must be on or off";
    }
    return NULL;
}

static const char *isapi_cmd_appendlogtoquery(cmd_parms *cmd, void *config, 
                                              char *arg)
{
    isapi_server_conf *sconf = ap_get_module_config(cmd->server->module_config,
                                                   &isapi_module);

    if (strcasecmp(arg, "on") == 0) {
        sconf->AppendLogToQuery = -1;
    }
    else if (strcasecmp(arg, "off") == 0) {
        sconf->AppendLogToQuery = 0;
    }
    else {
        return "ISAPIAppendLogToQuery must be on or off";
    }
    return NULL;
}

static const char *isapi_cmd_cachefile(cmd_parms *cmd, void *dummy, 
                                       const char *filename)

{
    isapi_server_conf *sconf = ap_get_module_config(cmd->server->module_config, 
                                                    &isapi_module);
    isapi_loaded *isa, **newisa;
    apr_finfo_t tmp;
    apr_status_t rv;
    char *fspec;
    
    fspec = ap_server_root_relative(cmd->pool, filename);
    if ((rv = apr_stat(&tmp, fspec, 
                 APR_FINFO_TYPE, cmd->temp_pool)) != APR_SUCCESS) { 
	ap_log_error(APLOG_MARK, APLOG_WARNING, rv, cmd->server,
	    "ISAPI: unable to stat(%s), skipping", filename);
	return NULL;
    }
    if (tmp.filetype != APR_REG) {
	ap_log_error(APLOG_MARK, APLOG_WARNING|APLOG_NOERRNO, 0, cmd->server,
	    "ISAPI: %s isn't a regular file, skipping", filename);
	return NULL;
    }

    /* Load the extention as cached (passing sconf) */
    rv = isapi_load(cmd->pool, sconf, NULL, fspec, &isa); 
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, cmd->server,
                     "ISAPI: unable to cache %s, skipping", filename);
	return NULL;
    }

    /* Add to cached list of loaded modules */
    newisa = apr_array_push(sconf->loaded);
    *newisa = isa;
    
    return NULL;
}

static void isapi_hooks(apr_pool_t *cont)
{
    ap_hook_post_config(isapi_post_config, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_handler(isapi_handler, NULL, NULL, APR_HOOK_MIDDLE);
}

static const command_rec isapi_cmds[] = {
AP_INIT_TAKE1("ISAPIReadAheadBuffer", isapi_cmd_readaheadbuffer, NULL, RSRC_CONF,
  "Maximum bytes to initially pass to the ISAPI handler"),
AP_INIT_TAKE1("ISAPILogNotSupported", isapi_cmd_lognotsupported, NULL, RSRC_CONF,
  "Log requests not supported by the ISAPI server"),
AP_INIT_TAKE1("ISAPIAppendLogToErrors", isapi_cmd_appendlogtoerrors, NULL, RSRC_CONF,
  "Send all Append Log requests to the error log"),
AP_INIT_TAKE1("ISAPIAppendLogToQuery", isapi_cmd_appendlogtoquery, NULL, RSRC_CONF,
  "Append Log requests are concatinated to the query args"),
AP_INIT_ITERATE("ISAPICacheFile", isapi_cmd_cachefile, NULL, RSRC_CONF,
  "Cache the specified ISAPI extension in-process"),
{ NULL }
};

module AP_MODULE_DECLARE_DATA isapi_module = {
   STANDARD20_MODULE_STUFF,
   NULL,                        /* create per-dir config */
   NULL,                        /* merge per-dir config */
   create_isapi_server_config,  /* server config */
   NULL,                        /* merge server config */
   isapi_cmds,                  /* command apr_table_t */
   isapi_hooks                  /* register hooks */
};
