source: rtems/cpukit/httpd/handler.c @ 19a0136

/*
 * handler.c -- URL handler support
 *
 * Copyright (c) GoAhead Software Inc., 1995-2000. All Rights Reserved.
 *
 * See the file "license.txt" for usage and redistribution license requirements
 *
 * $Id$
 */

/******************************** Description *********************************/

/*
 *      This module implements a URL handler interface and API to permit
 *      the addition of user definable URL processors.
 */

/********************************* Includes ***********************************/

#include        "wsIntrn.h"

/*********************************** Locals ***********************************/

static websUrlHandlerType       *websUrlHandler;                        /* URL handler list */
static int                                      websUrlHandlerMax;                      /* Number of entries */
static int                                      urlHandlerOpenCount = 0;        /* count of apps */

/**************************** Forward Declarations ****************************/

static int              websUrlHandlerSort(const void *p1, const void *p2);
static int              websPublishHandler(webs_t wp, char_t *urlPrefix, char_t *webDir, 
                                int sid, char_t *url, char_t *path, char_t *query);
static char_t   *websCondenseMultipleChars(char_t *strToCondense, char_t cCondense);

/*********************************** Code *************************************/
/*
 *      Initialize the URL handler module
 */

int websUrlHandlerOpen()
{
        if (++urlHandlerOpenCount == 1) {
                websAspOpen();
                websUrlHandler = NULL;
                websUrlHandlerMax = 0;
        }
        return 0;
}

/******************************************************************************/
/*
 *      Close the URL handler module
 */

void websUrlHandlerClose()
{
        websUrlHandlerType *sp;

        if (--urlHandlerOpenCount <= 0) {
                websAspClose();
                for (sp = websUrlHandler; sp < &websUrlHandler[websUrlHandlerMax];
                        sp++) {
                        bfree(B_L, sp->urlPrefix);
                        if (sp->webDir) {
                                bfree(B_L, sp->webDir);
                        }
                }
                bfree(B_L, websUrlHandler);
                websUrlHandlerMax = 0;
        }
}

/******************************************************************************/
/*
 *      Define a new URL handler. urlPrefix is the URL prefix to match. webDir is 
 *      an optional root directory path for a web directory. arg is an optional
 *      arg to pass to the URL handler. flags defines the matching order. Valid
 *      flags include WEBS_HANDLER_LAST, WEBS_HANDLER_FIRST. If multiple users 
 *      specify last or first, their order is defined alphabetically by the 
 *      urlPrefix.
 */

int websUrlHandlerDefine(char_t *urlPrefix, char_t *webDir, int arg,
                int (*handler)(webs_t wp, char_t *urlPrefix, char_t *webdir, int arg, 
                char_t *url, char_t *path, char_t *query), int flags)
{
        websUrlHandlerType      *sp;
        int                                     len;

        a_assert(urlPrefix);
        a_assert(handler);

/*
 *      Grow the URL handler array to create a new slot
 */
        len = (websUrlHandlerMax + 1) * sizeof(websUrlHandlerType);
        if ((websUrlHandler = brealloc(B_L, websUrlHandler, len)) == NULL) {
                return -1;
        }
        sp = &websUrlHandler[websUrlHandlerMax++];
        memset(sp, 0, sizeof(websUrlHandlerType));

        sp->urlPrefix = bstrdup(B_L, urlPrefix);
        sp->len = gstrlen(sp->urlPrefix);
        if (webDir) {
                sp->webDir = bstrdup(B_L, webDir);
        } else {
                sp->webDir = bstrdup(B_L, T(""));
        }
        sp->handler = handler;
        sp->arg = arg;
        sp->flags = flags;

/*
 *      Sort in decreasing URL length order observing the flags for first and last
 */
        qsort(websUrlHandler, websUrlHandlerMax, sizeof(websUrlHandlerType), 
                websUrlHandlerSort);
        return 0;
}

/******************************************************************************/
/*
 *      Delete an existing URL handler. We don't reclaim the space of the old 
 *      handler, just NULL the entry. Return -1 if handler is not found.
 */

int websUrlHandlerDelete(int (*handler)(webs_t wp, char_t *urlPrefix, 
        char_t *webDir, int arg, char_t *url, char_t *path, char_t *query))
{
        websUrlHandlerType      *sp;
        int                                     i;

        for (i = 0; i < websUrlHandlerMax; i++) {
                sp = &websUrlHandler[i];
                if (sp->handler == handler) {
                        sp->handler = NULL;
                        return 0;
                }
        }
        return -1;
}

/******************************************************************************/
/*
 *      Sort in decreasing URL length order observing the flags for first and last
 */

static int websUrlHandlerSort(const void *p1, const void *p2)
{
        websUrlHandlerType      *s1, *s2;
        int                                     rc;

        a_assert(p1);
        a_assert(p2);

        s1 = (websUrlHandlerType*) p1;
        s2 = (websUrlHandlerType*) p2;

        if ((s1->flags & WEBS_HANDLER_FIRST) || (s2->flags & WEBS_HANDLER_LAST)) {
                return -1;
        }

        if ((s2->flags & WEBS_HANDLER_FIRST) || (s1->flags & WEBS_HANDLER_LAST)) {
                return 1;
        }

        if ((rc = gstrcmp(s1->urlPrefix, s2->urlPrefix)) == 0) {
                if (s1->len < s2->len) {
                        return 1;
                } else if (s1->len > s2->len) {
                        return -1;
                }
        }
        return -rc; 
}

/******************************************************************************/
/*
 *      Publish a new web directory (Use the default URL handler)
 */

int websPublish(char_t *urlPrefix, char_t *path)
{
        return websUrlHandlerDefine(urlPrefix, path, 0, websPublishHandler, 0);
}

/******************************************************************************/
/*
 *      Return the directory for a given prefix. Ignore empty prefixes
 */

char_t *websGetPublishDir(char_t *path, char_t **urlPrefix)
{
        websUrlHandlerType      *sp;
        int                                     i;

        for (i = 0; i < websUrlHandlerMax; i++) {
                sp = &websUrlHandler[i];
                if (sp->urlPrefix[0] == '\0') {
                        continue;
                }
                if (sp->handler && gstrncmp(sp->urlPrefix, path, sp->len) == 0) {
                        if (urlPrefix) {
                                *urlPrefix = sp->urlPrefix;
                        }
                        return sp->webDir;
                }
        }
        return NULL;
}

/******************************************************************************/
/*
 *      Publish URL handler. We just patch the web page Directory and let the
 *      default handler do the rest.
 */

static int websPublishHandler(webs_t wp, char_t *urlPrefix, char_t *webDir, 
        int sid, char_t *url, char_t *path, char_t *query)
{
        int             len;

        a_assert(websValid(wp));
        a_assert(path);

/*
 *      Trim the urlPrefix off the path and set the webdirectory. Add one to step 
 *      over the trailing '/'
 */
        len = gstrlen(urlPrefix) + 1;
        websSetRequestPath(wp, webDir, &path[len]);
        return 0;
}

/******************************************************************************/
/*
 *      See if any valid handlers are defined for this request. If so, call them
 *      and continue calling valid handlers until one accepts the request. 
 *      Return true if a handler was invoked, else return FALSE.
 */

int websUrlHandlerRequest(webs_t wp)
{
        websUrlHandlerType      *sp;
        int                                     i, first;

        a_assert(websValid(wp));

/*
 *      Delete the socket handler as we don't want to start reading any
 *      data on the connection as it may be for the next pipelined HTTP/1.1
 *      request if using Keep Alive
 */
        socketDeleteHandler(wp->sid);
        wp->state = WEBS_PROCESSING;
        websStats.handlerHits++;
        
        websSetRequestPath(wp, websGetDefaultDir(), NULL);

/*
 *      Eliminate security hole
 */
        websCondenseMultipleChars(wp->path, '/');
        websCondenseMultipleChars(wp->url, '/');

/*
 *      We loop over each handler in order till one accepts the request. 
 *      The security handler will handle the request if access is NOT allowed.
 */
        first = 1;
        for (i = 0; i < websUrlHandlerMax; i++) {
                sp = &websUrlHandler[i];
                if (sp->handler && gstrncmp(sp->urlPrefix, wp->path, sp->len) == 0) {
                        if (first) {
                                websSetEnv(wp);
                                first = 0;
                        }
                        if ((*sp->handler)(wp, sp->urlPrefix, sp->webDir, sp->arg, 
                                        wp->url, wp->path, wp->query)) {
                                return 1;
                        }
                        if (!websValid(wp)) {
                                trace(0, 
                                T("webs: handler %s called websDone, but didn't return 1\n"),
                                        sp->urlPrefix);
                                return 1;
                        }
                }
        }
/*
 *      If no handler processed the request, then return an error. Note: It is 
 *      the handlers responsibility to call websDone
 */
        if (i >= websUrlHandlerMax) {
                websError(wp, 200, T("No handler for this URL %s"), wp->url);
        }
        return 0;
}

#ifdef OBSOLETE_CODE

/******************************************************************************/
/*
 *      Tidy up the URL path. Return -1 if the URL is bad.
 *  Used to eliminate repeated directory delimiters ('/').
 */

static int websTidyUrl(webs_t wp)
{
        char_t  *parts[64];                                     /* Array of ptr's to URL parts */
        char_t  *token, *url, *tidyurl;
        int             i, len, npart;

        a_assert(websValid(wp));

/*
 *      Copy the string so we don't destroy the original (yet)
 */
        url = bstrdup(B_L, wp->url);
        websDecodeUrl(url, url, gstrlen(url));

        len = npart = 0;
        parts[0] = NULL;
        token = gstrtok(url, T("/"));

/*
 *      Look at each directory segment and process "." and ".." segments
 *      Don't allow the browser to pop outside the root web. 
 */
        while (token != NULL) {
                if (gstrcmp(token, T("..")) == 0) {
                        if (npart > 0) {
                                npart--;
                        }

                } else if (gstrcmp(token, T(".")) != 0) {
                        parts[npart] = token;
                        len += gstrlen(token) + 1;
                        npart++;
                }
                token = gstrtok(NULL, T("/"));
        }

/*
 *      Re-construct URL. Need extra space all "/" and null.
 */
        if (npart || (gstrcmp(url, T("/")) == 0) || (url[0] == '\0')) {
                tidyurl = balloc(B_L, (len + 2) * sizeof(char_t));
                *tidyurl = '\0';

                for (i = 0; i < npart; i++) {
                        gstrcat(tidyurl, T("/"));
                        gstrcat(tidyurl, parts[i]);
                }

                bfree(B_L, url);

                bfree(B_L, wp->url);
                wp->url = tidyurl;
                return 0;
        } else {
                bfree(B_L, url);
                return -1;
        }
}

#endif

/******************************************************************************/
/*
 *      Convert multiple adjacent occurrences of a given character to a single
 *      instance.
 */

static char_t *websCondenseMultipleChars(char_t *strToCondense, char_t cCondense)
{
        if (strToCondense != NULL) {
                char_t *pStr, *pScan;

                pStr = pScan = strToCondense;

                while (*pScan && *pStr) {
/*
 *                      Advance scan pointer over multiple occurences of condense character
 */
                        while ((*pScan == cCondense) && (*(pScan + 1) == cCondense)) {
                                pScan++;
                        }
/*
 *                      Copy character if an advance of the scan pointer has occurred
 */
                        if (pStr != pScan) {
                                *pStr = *pScan;
                        }
                        
                        pScan++;
                        pStr++;
                }
/*
 *              Zero terminate string if multiple adjacent characters were found and condensed
 */
                if (pStr != pScan) {
                        *pStr = 0;
                }
        }

        return strToCondense;
}

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