mod_isapi.c

Apache V2.0.15 Alpha For Linuxhttpd-2_0_15-alpha.tar.Z

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 * Portions of this software are based upon public domain software
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/*
 * mod_isapi.c - Internet Server Application (ISA) module for Apache
 * by Alexei Kosut <[e-mail]>
 *
 * 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 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 lpwdwBytes,
                         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 {
    HANDLE lock;
    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 BOOL isapi_unload(isapi_loaded* isa, int force);

static apr_status_t cleanup_isapi_server_config(void *sconfv)
{
    isapi_server_conf *sconf = sconfv;
    size_t n;
    isapi_loaded **isa;
 
    n = sconf->loaded->nelts;
    isa = (isapi_loaded **)sconf->loaded->elts;
    while(n--) {
        if ((*isa)->handle)
            isapi_unload(*isa, TRUE); 
        ++isa;
    }
    CloseHandle(sconf->lock);
    return APR_SUCCESS;
}

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->lock = CreateMutex(NULL, FALSE, NULL);

    sconf->ReadAheadBuffer = 49152;
    sconf->LogNotSupported    = -1;
    sconf->AppendLogToErrors   = 0;
    sconf->AppendLogToQuery    = 0;

    apr_pool_cleanup_register(p, sconf, cleanup_isapi_server_config, 
                                   apr_pool_cleanup_null);

    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 void 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 the virtualhosts share the same thing */
    for (s = s->next; s; s = s->next) {
	ap_set_module_config(s->module_config, &isapi_module, sconf);
    }
}

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;