source: rtems/cpukit/httpd/webs.c @ c1cdaa0

/*
 * webs.c -- GoAhead Embedded HTTP webs server
 *
 * Copyright (c) Go Ahead Software Inc., 1995-1999. All Rights Reserved.
 *
 * See the file "license.txt" for usage and redistribution license requirements
 */

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

/*
 *      This module implements an embedded HTTP/1.1 webs server. It supports
 *      loadable URL handlers that define the nature of URL processing performed.
 */

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

#include        "wsIntrn.h"

/******************************** Global Data *********************************/

websStatsType    websStats;                             /* Web access stats */
webs_t                  *webs;                                  /* Open connection list head */
sym_fd_t                 websMime;                              /* Set of mime types */
int                              websMax;                               /* List size */
int                              websPort;                              /* Listen port for server */
char_t                   websHost[64];                  /* Host name for the server */
char_t                   websIpaddr[64];                /* IP address for the server */
char_t                  *websHostUrl = NULL;    /* URL to access server */

/*********************************** Locals ***********************************/
/*
 *      Standard HTTP error codes
 */

websErrorType websErrors[] = {
        { 200, T("Data follows") },
        { 204, T("No Content") },
        { 301, T("Redirect") },
        { 302, T("Redirect") },
        { 304, T("User local copy") },
        { 400, T("Page not found") },
        { 401, T("Password Required") },
        { 404, T("Site or Page Not Found") },
        { 405, T("Access Denied") },
        { 500, T("Web Error") },
        { 503, T("Site Temporarily Unavailable. Try again") },
        { 0, NULL }
};

#if WEBS_LOG_SUPPORT
static char_t   websLogname[64] = T("log.txt"); /* Log filename */
static int              websLogFd;                                              /* Log file handle */
#endif

static int              websListenSock;                                 /* Listen socket */

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

static int               websAccept(int sid, char *ipaddr, int port);
static int               websAlloc(int sid);
static char_t   *websErrorMsg(int code);
static void      websFree(webs_t wp);
static void              websFreeVar(sym_t* sp);
static int               websGetInput(webs_t wp, char_t **ptext, int *nbytes);
static int               websParseFirst(webs_t wp, char_t *text);
static void      websParseRequest(webs_t wp);
static void      websReadEvent(webs_t wp);
static void              websSocketEvent(int sid, int mask, int data);
static void      websTimeout(long wp);
static void      websTimeoutCancel(webs_t wp);
static void              websMarkTime(webs_t wp);
static int               websGetTimeSinceMark(webs_t wp);

#if WEBS_LOG_SUPPORT
static void      websLog(webs_t wp, int code);
#endif
#if WEBS_IF_MODIFIED_SUPPORT
static time_t dateParse(time_t tip, char_t *cmd);
#endif

/*********************************** Code *************************************/
/*
 *      Open the GoAhead WebServer
 */

int websOpenServer(int port, int retries)
{
        websMimeType    *mt;

        a_assert(port > 0);
        a_assert(retries >= 0);

#if WEBS_PAGE_ROM
        websRomOpen();
#endif

/*
 *      Create a mime type lookup table for quickly determining the content type
 */
        websMime = symOpen(256);
        a_assert(websMime >= 0);
        for (mt = websMimeList; mt->type; mt++) {
                symEnter(websMime, mt->ext, valueString(mt->type, 0), 0);
        }

/*
 *      Open the URL handler module. The caller should create the required
 *      URL handlers after calling this function.
 */
        if (websUrlHandlerOpen() < 0) {
                return -1;
        }

#if WEBS_LOG_SUPPORT
/*
 *      Optional request log support
 */
        websLogFd = gopen(websLogname, O_CREAT | O_TRUNC | O_APPEND | O_WRONLY, 
                0666);
        a_assert(websLogFd >= 0);
#endif
        
        return websOpenListen(port, retries);
}

/******************************************************************************/
/*
 *      Close the GoAhead WebServer
 */

void websCloseServer()
{
        webs_t  wp;
        int             wid;

/*
 *      Close the listen handle first then all open connections.
 */
        websCloseListen();

/* 
 *      Close each open browser connection and free all resources
 */
        for (wid = websMax; webs && wid >= 0; wid--) {
                if ((wp = webs[wid]) == NULL) {
                        continue;
                }
                socketCloseConnection(wp->sid);
                websFree(wp);
        }

#if WEBS_LOG_SUPPORT
        if (websLogFd >= 0) {
                close(websLogFd);
                websLogFd = -1;
        }
#endif

#if WEBS_PAGE_ROM
        websRomClose();
#endif
        symClose(websMime, NULL);
        websFormClose();
        websUrlHandlerClose();
}

/******************************************************************************/
/*
 *      Open the GoAhead WebServer listen port
 */

int websOpenListen(int port, int retries)
{
        int             i, orig;

        a_assert(port > 0);
        a_assert(retries >= 0);

        orig = port;
/*
 *      Open the webs webs listen port. If we fail, try the next port.
 */
        for (i = 0; i <= retries; i++) {
                websListenSock = socketOpenConnection(NULL, port, websAccept, 0);
                if (websListenSock >= 0) {
                        break;
                }
                port++;
        }
        if (i > retries) {
                error(E_L, E_USER, T("Couldn't open a socket on ports %d - %d"),
                        orig, port - 1);
                return -1;
        } 
        trace(0, T("webs: Listening for HTTP requests on port %d\n"), port);

/*
 *      Determine the full URL address to access the home page for this web server
 */
        websPort = port;
        bfreeSafe(B_L, websHostUrl);
        websHostUrl = NULL;
        if (port == 80) {
                websHostUrl = bstrdup(B_L, websHost);
        } else {
                gsnprintf(&websHostUrl, WEBS_MAX_URL + 80, T("%s:%d"), websHost, port);
        }
        return port;
}

/******************************************************************************/
/*
 *      Close webs listen port
 */

void websCloseListen()
{
        if (websListenSock >= 0) {
                socketCloseConnection(websListenSock);
                websListenSock = -1;
        }
        bfreeSafe(B_L, websHostUrl);
        websHostUrl = NULL;
}

/******************************************************************************/
/*
 *      Accept a connection
 */

static int websAccept(int sid, char *ipaddr, int port)
{
        webs_t  wp;
        int             wid;

        a_assert(ipaddr && *ipaddr);
        a_assert(sid >= 0);
        a_assert(port >= 0);

/*
 *      Allocate a new handle for this accepted connection. This will allocate
 *      a webs_t structure in the webs[] list
 */
        if ((wid = websAlloc(sid)) < 0) {
                return -1;
        }
        wp = webs[wid];
        a_assert(wp);

        ascToUni(wp->ipaddr, ipaddr, sizeof(wp->ipaddr));

/*
 *      Check if this is a request from a browser on this system. This is useful
 *      to know for permitting administrative operations only for local access
 */
        if (gstrcmp(wp->ipaddr, T("127.0.0.1")) == 0 || 
                        gstrcmp(wp->ipaddr, websIpaddr) == 0 || 
                        gstrcmp(wp->ipaddr, websHost) == 0) {
                wp->flags |= WEBS_LOCAL_REQUEST;
        }

/*
 *      Arrange for websSocketEvent to be called when read data is available
 */
        socketCreateHandler(sid, SOCKET_READABLE , websSocketEvent, (int) wp);

/*
 *      Arrange for a timeout to kill hung requests
 */
        wp->timeout = emfCreateTimer(WEBS_TIMEOUT, websTimeout, (long) wp);
        trace(5, T("webs: accept request\n"));
        return 0;
}

/******************************************************************************/
/*
 *      The webs socket handler.  Called in response to I/O. We just pass control
 *      to the relevant read or write handler. A pointer to the webs structure
 *      is passed as an (int) in iwp.
 */

static void websSocketEvent(int sid, int mask, int iwp)
{
        webs_t  wp;

        wp = (webs_t) iwp;
        a_assert(wp);

        if (! websValid(wp)) {
                return;
        }

        if (mask & SOCKET_READABLE) {
                websReadEvent(wp);
        } 
        if (mask & SOCKET_WRITABLE) {
                if (wp->writeSocket) {
                        (*wp->writeSocket)(wp);
                }
        } 
}

/******************************************************************************/
/*
 *      The webs read handler. This is the primary read event loop. It uses a
 *      state machine to track progress while parsing the HTTP request. 
 *      Note: we never block as the socket is always in non-blocking mode.
 */

static void websReadEvent(webs_t wp)
{
        char_t  *text;
        int             rc, nbytes, len, done;

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

        websMarkTime(wp);

/*
 *      Read as many lines as possible. socketGets is called to read the header
 *      and socketRead is called to read posted data.
 */
        text = NULL;
        for (done = 0; !done; ) {
                if (text) {
                        bfree(B_L, text);
                        text = NULL;
                }

/*
 *              Get more input into "text". Returns 0, if more data is needed
 *              to continue, -1 if finished with the request, or 1 if all 
 *              required data is available for current state.
 */
                while ((rc = websGetInput(wp, &text, &nbytes)) == 0) {
                        ;
                }

/*
 *              websGetInput returns -1 if it finishes with the request
 */
                if (rc < 0) {
                        break;
                }

/*
 *              This is the state machine for the web server. 
 */
                switch(wp->state) {
                case WEBS_BEGIN:
/*
 *                      Parse the first line of the Http header
 */
                        if (websParseFirst(wp, text) < 0) {
                                done++;
                                break;
                        }
                        wp->state = WEBS_HEADER;
                        break;
                
                case WEBS_HEADER:
/*
 *                      Store more of the HTTP header. As we are doing line reads, we
 *                      need to separate the lines with '\n'
 */
                        if (ringqLen(&wp->header) > 0) {
                                ringqPutstr(&wp->header, T("\n"));
                        }
                        ringqPutstr(&wp->header, text);
                        break;

                case WEBS_POST_CLEN:
/*
 *                      POST request with content specified by a content length
 */
                        if (wp->query) {
                                if (wp->query[0] && !(wp->flags & WEBS_POST_DATA)) {
/*
 *                                      Special case where the POST request also had query data 
 *                                      specified in the URL, ie. url?query_data. In this case
 *                                      the URL query data is separated by a '&' from the posted
 *                                      query data.
 */
                                        len = gstrlen(wp->query);
                                        wp->query = brealloc(B_L, wp->query, (len + gstrlen(text) +
                                                2) * sizeof(char_t));
                                        wp->query[len++] = '&';
                                        gstrcpy(&wp->query[len], text);

                                } else {
/*
 *                                      The existing query data came from the POST request so just
 *                                      append it.
 */
                                        len = gstrlen(wp->query);
                                        wp->query = brealloc(B_L, wp->query, (len +     gstrlen(text) +
                                                1) * sizeof(char_t));
                                        if (wp->query) {
                                                gstrcpy(&wp->query[len], text);
                                        }
                                }

                        } else {
                                wp->query = bstrdup(B_L, text);
                        }
/*
 *                      Calculate how much more post data is to be read.
 */
                        wp->flags |= WEBS_POST_DATA;
                        wp->clen -= nbytes;
                        if (wp->clen > 0) {
                                if (nbytes > 0) {
                                        done++;
                                        break;
                                }
                                done++;
                                break;
                        }
/*
 *                      No more data so process the request
 */
                        websUrlHandlerRequest(wp);
                        done++;
                        break;

                case WEBS_POST:
/*
 *                      POST without content-length specification
 */
                        if (wp->query && *wp->query && !(wp->flags & WEBS_POST_DATA)) {
                                len = gstrlen(wp->query);
                                wp->query = brealloc(B_L, wp->query, (len + gstrlen(text) +
                                        2) * sizeof(char_t));
                                if (wp->query) {
                                        wp->query[len++] = '&';
                                        gstrcpy(&wp->query[len], text);
                                }

                        } else {
                                wp->query = bstrdup(B_L, text);
                        }
                        wp->flags |= WEBS_POST_DATA;
                        done++;
                        break;

                default:
                        websError(wp, 404, T("Bad state"));
                        done++;
                        break;
                }
        }
        if (text) {
                bfree(B_L, text);
        }
}

/******************************************************************************/
/*
 *      Get input from the browser. Return TRUE (!0) if the request has been 
 *      handled. Return -1 on errors, 1 if input read, and 0 to instruct the 
 *      caller to call again for more input.
 *
 *      Note: socketRead will Return the number of bytes read if successful. This
 *      may be less than the requested "bufsize" and may be zero. It returns -1 for
 *      errors. It returns 0 for EOF. Otherwise it returns the number of bytes 
 *      read. Since this may be zero, callers should use socketEof() to 
 *      distinguish between this and EOF.
 */

static int websGetInput(webs_t wp, char_t **ptext, int *pnbytes) 
{
        char_t  *text;
        char    buf[WEBS_SOCKET_BUFSIZ+1];
        int             nbytes, len, clen;

        a_assert(websValid(wp));
        a_assert(ptext);
        a_assert(pnbytes);

        *ptext = text = NULL;
        *pnbytes = 0;

/*
 *      If this request is a POST with a content length, we know the number
 *      of bytes to read so we use socketRead().
 */
        if (wp->state == WEBS_POST_CLEN) {
                len = (wp->clen > WEBS_SOCKET_BUFSIZ) ? WEBS_SOCKET_BUFSIZ : wp->clen;
        } else {
                len = 0;
        }

        if (len > 0) {
                nbytes = socketRead(wp->sid, buf, len);

                if (nbytes < 0) {                                               /* Error */
                        websDone(wp, 0);
                        return -1;

                }  else if (nbytes == 0) {                              /* EOF or No data available */
                        return -1;

                } else {                                                                /* Valid data */
/*
 *                      Convert to UNICODE if necessary.  First be sure the string 
 *                      is NULL terminated.
 */
                        buf[nbytes] = '\0';
                        if ((text = ballocAscToUni(buf)) == NULL) {
                                websError(wp, 503, T("Insufficient memory"));
                                return -1;
                        }
                }

        } else {
                nbytes = socketGets(wp->sid, &text);

                if (nbytes < 0) {
/*
 *                      Error, EOF or incomplete
 */
                        if (socketEof(wp->sid)) {
/*
 *                              If this is a post request without content length, process 
 *                              the request as we now have all the data. Otherwise just 
 *                              close the connection.
 */
                                if (wp->state == WEBS_POST) {
                                        websUrlHandlerRequest(wp);
                                } else {
                                        websDone(wp, 0);
                                }
                        }
/*
 *                      If state is WEBS_HEADER and the ringq is empty, then this is a
 *                      simple request with no additional header fields to process and
 *                      no empty line terminator.
 */
                        if (wp->state == WEBS_HEADER && ringqLen(&wp->header) <= 0) {
                                websParseRequest(wp);
                                websUrlHandlerRequest(wp);
                        }
                        return -1;

                } else if (nbytes == 0) {
                        if (wp->state == WEBS_HEADER) {
/*
 *                              Valid empty line, now finished with header
 */
                                websParseRequest(wp);
                                if (wp->flags & WEBS_POST_REQUEST) {
                                        if (wp->flags & WEBS_CLEN) {
                                                wp->state = WEBS_POST_CLEN;
                                                clen = wp->clen;
                                        } else {
                                                wp->state = WEBS_POST;
                                                clen = 1;
                                        }
                                        if (clen > 0) {
                                                return 0;                                                       /* Get more data */
                                        }
                                        return 1;

                                }
/*
 *                              We've read the header so go and handle the request
 */
                                websUrlHandlerRequest(wp);
                        }
                        return -1;

                }
        }
        a_assert(text);
        a_assert(nbytes > 0);
        *ptext = text;
        *pnbytes = nbytes;
        return 1;
}

/******************************************************************************/
/*
 *      Parse the first line of a HTTP request
 */

static int websParseFirst(webs_t wp, char_t *text)
{
        char_t  *op, *proto, *url, *host, *query, *path, *port, *ext, *buf;

        a_assert(websValid(wp));
        a_assert(text && *text);

/*
 *      Determine the request type: GET, HEAD or POST
 */
        op = gstrtok(text, T(" \t"));
        if (op == NULL || *op == '\0') {
                websError(wp, 400, T("Bad HTTP request"));
                return -1;
        }
        if (gstrcmp(op, T("GET")) != 0) {
                if (gstrcmp(op, T("POST")) == 0) {
                        wp->flags |= WEBS_POST_REQUEST;
                } else if (gstrcmp(op, T("HEAD")) == 0) {
                        wp->flags |= WEBS_HEAD_REQUEST;
                } else {
                        websError(wp, 400, T("Bad request type"));
                        return -1;
                }
        }

/*
 *      Store result in the form (CGI) variable store
 */
        websSetVar(wp, T("REQUEST_METHOD"), op);

        url = gstrtok(NULL, T(" \t\n"));
        if (url == NULL || *url == '\0') {
                websError(wp, 400, T("Bad HTTP request"));
                return -1;
        }

/*
 *      Parse the URL and store all the various URL components. websUrlParse
 *      returns an allocated buffer in buf which we must free. We support both
 *      proxied and non-proxied requests. Proxied requests will have http://host/
 *      at the start of the URL. Non-proxied will just be local path names.
 */
        host = path = port = proto = query = ext = NULL;
        if (websUrlParse(url, &buf, &host, &path, &port, &query, &proto, 
                        NULL, &ext) < 0) {
                websError(wp, 400, T("Bad URL format"));
                return -1;
        }

        wp->url = bstrdup(B_L, url);
        wp->query = bstrdup(B_L, query);
        wp->host = bstrdup(B_L, host);
        wp->path = bstrdup(B_L, path);
        wp->port = gatoi(port);
        if (gstrcmp(ext, T(".asp")) == 0) {
                wp->flags |= WEBS_ASP;
        }
        bfree(B_L, buf);

        websUrlType(url, wp->type, TSZ(wp->type));

#if WEBS_PROXY_SUPPORT
/*
 *      Determine if this is a request for local webs data. If it is not a proxied 
 *      request from the browser, we won't see the "http://" or the system name, so
 *      we assume it must be talking to us directly for local webs data.
 *      Note: not fully implemented yet.
 */
        if (gstrstr(wp->url, T("http://")) == NULL || 
                ((gstrcmp(wp->host, T("localhost")) == 0 || 
                        gstrcmp(wp->host, websHost) == 0) && (wp->port == websPort))) {
                wp->flags |= WEBS_LOCAL_PAGE;
                if (gstrcmp(wp->path, T("/")) == 0) {
                        wp->flags |= WEBS_HOME_PAGE;
                }
        }
#endif

        ringqFlush(&wp->header);
        return 0;
}

/******************************************************************************/
/*
 *      Parse a full request
 */

static void websParseRequest(webs_t wp)
{
        char_t  *upperKey, *cp, *browser, *lp, *key, *value;

        a_assert(websValid(wp));

/*
 *      Define default CGI values
 */
        websSetVar(wp, T("HTTP_AUTHORIZATION"), T(""));

/* 
 *      Parse the header and create the Http header keyword variables
 *      We rewrite the header as we go for non-local requests.  NOTE: this
 *      modifies the header string directly and tokenizes each line with '\0'.
 */
        browser = NULL;
        for (lp = (char_t*) wp->header.servp; lp && *lp; ) {
                cp = lp;
                if ((lp = gstrchr(lp, '\n')) != NULL) {
                        lp++;
                }

                if ((key = gstrtok(cp, T(": \t\n"))) == NULL) {
                        continue;
                }

                if ((value = gstrtok(NULL, T("\n"))) == NULL) {
                        value = T("");
                }

                while (gisspace(*value)) {
                        value++;
                }
                strlower(key);

/*
 *              Create a variable (CGI) for each line in the header
 */
                gsnprintf(&upperKey, (gstrlen(key) + 6), T("HTTP_%s"), key);
                for (cp = upperKey; *cp; cp++) {
                        if (*cp == '-')
                                *cp = '_';
                }
                strupper(upperKey);
                websSetVar(wp, upperKey, value);
                bfree(B_L, upperKey);

/*
 *              Track the requesting agent (browser) type
 */
                if (gstrcmp(key, T("user-agent")) == 0) {
                        wp->userAgent = bstrdup(B_L, value);

/*
 *              Parse the user authorization. ie. password
 */
                } else if (gstrcmp(key, T("authorization")) == 0) {
                        char_t  password[FNAMESIZE];

/*
 *                      The incoming value is password:username
 */
                        if ((cp = gstrchr(value, ' ')) != NULL) {
                                websDecode64(password, ++cp, sizeof(password));
                        } else {
                                websDecode64(password, value, sizeof(password));
                        }
                        if ((cp = gstrchr(password, ':')) != NULL) {
                                *cp++ = '\0';
                        }
                        if (cp) {
                                wp->password = bstrdup(B_L, cp);
                        } else {
                                wp->password = bstrdup(B_L, T(""));
                        }

/*
 *              Parse the content length
 */
                } else if (gstrcmp(key, T("content-length")) == 0) {
                        wp->flags |= WEBS_CLEN;
                        wp->clen = gatoi(value);
                        websSetVar(wp, T("CONTENT_LENGTH"), value);

#if WEBS_KEEP_ALIVE_SUPPORT
                } else if (gstrcmp(key, T("connection")) == 0) {
                        strlower(value);
                        if (gstrcmp(value, T("keep-alive")) == 0) {
                                wp->flags |= WEBS_KEEP_ALIVE;
                        }
#endif

#if WEBS_PROXY_SUPPORT
/*
 *              This may be useful if you wish to keep a local cache of web pages
 *              for proxied requests.
 */
                } else if (gstrcmp(key, T("pragma")) == 0) {
                        char_t  tmp[256];
                        gstrncpy(tmp, value, TSZ(tmp));
                        strlower(tmp);
                        if (gstrstr(tmp, T("no-cache"))) {
                                wp->flags |= WEBS_DONT_USE_CACHE;
                        }
#endif

/*
 *              Store the cookie
 */
                } else if (gstrcmp(key, T("cookie")) == 0) {
                        wp->flags |= WEBS_COOKIE;
                        wp->cookie = bstrdup(B_L, value);

#if WEBS_IF_MODIFIED_SUPPORT
/*
 *              See if the local page has been modified since the browser last
 *              requested this document. If not, just return a 302
 */
                } else if (gstrcmp(key, T("if-modified-since")) == 0) {
                        char_t *cmd;
                        time_t tip = 0;

                        if (cp = gstrchr(value, ';')) {
                                *cp = '\0';
                        }

                        if (cp = gstrstr(value, T(", "))) {
                                cp += 2;
                        }

                        if (gstrstr(cp, T("GMT"))) {
                                gsnprintf(&cmd, 64, T("clock scan %s -gmt 1"), cp);
                        } else {
                                gsnprintf(&cmd, 64, T("clock scan %s"), cp);
                        }
                        if (wp->since = dateParse(tip, cmd)) {
                                wp->flags |= WEBS_IF_MODIFIED;
                        }
                        bfreeSafe(B_L, cmd);
#endif
                }
        }
}


#if WEBS_IF_MODIFIED_SUPPORT
/******************************************************************************/
/*
 *              Parse the date and time string.
 */

static time_t dateParse(time_t tip, char_t *cmd)
{
        return (time_t)0;
}
#endif


/******************************************************************************/
/*
 *      Set the variable (CGI) environment for this request. Create variables
 *      for all standard CGI variables. Also decode the query string and create
 *      a variable for each name=value pair.
 */

void websSetEnv(webs_t wp)
{
        char_t  portBuf[8];
        char_t  *keyword, *value;

        a_assert(websValid(wp));

        websSetVar(wp, T("QUERY_STRING"), wp->query);
        websSetVar(wp, T("GATEWAY_INTERFACE"), T("CGI/1.1"));
        websSetVar(wp, T("SERVER_HOST"), websHost);
        websSetVar(wp, T("SERVER_URL"), websHostUrl);
        websSetVar(wp, T("REMOTE_HOST"), wp->ipaddr);
        websSetVar(wp, T("REMOTE_ADDR"), wp->ipaddr);
        websSetVar(wp, T("PATH_INFO"), wp->path);
        stritoa(websPort, portBuf, sizeof(portBuf));
        websSetVar(wp, T("SERVER_PORT"), portBuf);
        
/*
 *      Decode and create an environment query variable for each query keyword.
 *      We split into pairs at each '&', then split pairs at the '='.
 *      Note: we rely on wp->decodedQuery preserving the decoded values in the
 *      symbol table.
 */
        wp->decodedQuery = bstrdup(B_L, wp->query);
        keyword = gstrtok(wp->decodedQuery, T("&"));
        while (keyword != NULL) {
                if ((value = gstrchr(keyword, '=')) != NULL) {
                        *value++ = '\0';
                        websDecodeUrl(keyword, keyword, gstrlen(keyword));
                        websDecodeUrl(value, value, gstrlen(value));

                } else {
                        value = T("");
                }

                if (*keyword) {
                        websSetVar(wp, keyword, value);
                }
                keyword = gstrtok(NULL, T("&"));
        }

#if EMF
/*
 *      Add GoAhead Embedded Management Framework defines
 */
        websSetEmfEnvironment(wp);
#endif
}

/******************************************************************************/
/*
 *      Define a webs (CGI) variable for this connection. Also create in relevant
 *      scripting engines. Note: the incoming value may be volatile. 
 */

void websSetVar(webs_t wp, char_t *var, char_t *value)
{
        value_t          v;

        a_assert(websValid(wp));

/*
 *      value_instring will allocate the string if required.
 */
        if (value) {
                v = valueString(value, VALUE_ALLOCATE);
        } else {
                v = valueString(T(""), VALUE_ALLOCATE);
        }
        symEnter(wp->cgiVars, var, v, 0);
}

/******************************************************************************/
/*
 *      Return TRUE if a webs variable exists for this connection.
 */

int websTestVar(webs_t wp, char_t *var)
{
        sym_t           *sp;

        a_assert(websValid(wp));

        if (var == NULL || *var == '\0') {
                return 0;
        }

        if ((sp = symLookup(wp->cgiVars, var)) == NULL) {
                return 0;
        }
        return 1;
}

/******************************************************************************/
/*
 *      Get a webs variable but return a default value if string not found.
 *      Note, defaultGetValue can be NULL to permit testing existance.
 */

char_t *websGetVar(webs_t wp, char_t *var, char_t *defaultGetValue)
{
        sym_t   *sp;

        a_assert(websValid(wp));
        a_assert(var && *var);
 
        if ((sp = symLookup(wp->cgiVars, var)) != NULL) {
                a_assert(sp->content.type == string);
                if (sp->content.value.string) {
                        return sp->content.value.string;
                } else {
                        return T("");
                }
        }
        return defaultGetValue;
}

/******************************************************************************/
/*
 *      Cancel the request timeout. Note may be called multiple times.
 */

static void websTimeoutCancel(webs_t wp)
{
        a_assert(websValid(wp));

        if (wp->timeout) {
                emfDeleteTimer(wp->timeout);
                wp->timeout = NULL;
        }
}

/******************************************************************************/
/*
 *      Output a HTTP response back to the browser. If redirect is set to a 
 *      URL, the browser will be sent to this location.
 */

void websResponse(webs_t wp, int code, char_t *message, char_t *redirect)
{
        char_t          *date;

        a_assert(websValid(wp));

/*
 *      IE3.0 needs no Keep Alive for some return codes.
 */
        wp->flags &= ~WEBS_KEEP_ALIVE;

/*
 *      Only output the header if a header has not already been output.
 */
        if ( !(wp->flags & WEBS_HEADER_DONE)) {
                wp->flags |= WEBS_HEADER_DONE;
                websWrite(wp, T("HTTP/1.0 %d %s\r\n"), code, websErrorMsg(code));

                /* by license terms the following line of code must
                 * not be modified.
                 */
                websWrite(wp, T("Server: GoAhead-Webs\r\n"));

                if (wp->flags & WEBS_KEEP_ALIVE) {
                        websWrite(wp, T("Connection: keep-alive\r\n"));
                }
                websWrite(wp, T("Pragma: no-cache\r\nCache-Control: no-cache\r\n"));

                if ((date = websGetDateString(NULL)) != NULL) {
                        websWrite(wp, T("Date: %s\r\n"), date);
                        bfree(B_L, date);
                }
                websWrite(wp, T("Content-Type: text/html\r\n"));

/*
 *              We don't do a string length here as the message may be multi-line. 
 *              Ie. <CR><LF> will count as only one and we will have a content-length 
 *              that is too short.
 *
 *              websWrite(wp, T("Content-Length: %s\r\n"), message);
 */
                if (redirect) {
                        websWrite(wp, T("Location: %s\r\n"), redirect);
                }
                websWrite(wp, T("\r\n"));
        }

        if (message && *message) {
                websWrite(wp, T("%s\r\n"), message);
        }
        websDone(wp, code);
}

/******************************************************************************/
/*
 *      Redirect the user to another webs page
 */

void websRedirect(webs_t wp, char_t *url)
{
        char_t  *msgbuf, *urlbuf;

        a_assert(websValid(wp));
        a_assert(url);

        websStats.redirects++;
        msgbuf = urlbuf = NULL;

/*
 *      Some browsers require a http://host qualified URL for redirection
 */
        if (gstrstr(url, T("http://")) == NULL) {
                if (*url == '/') {
                        url++;
                }
                gsnprintf(&urlbuf, WEBS_MAX_URL + 80, T("http://%s/%s"),
                        websGetVar(wp, T("HTTP_HOST"),  websHostUrl), url);
                url = urlbuf;
        }

/*
 *      Add human readable message for completeness. Should not be required.
 */
        gsnprintf(&msgbuf, WEBS_MAX_URL + 80, 
                T("<html><head></head><body>\r\n\
                This document has moved to a new <a href=\"%s\">location</a>.\r\n\
                Please update your documents to reflect the new location.\r\n\
                </body></html>\r\n"), url);

        websResponse(wp, 302, msgbuf, url);

        bfreeSafe(B_L, msgbuf);
        bfreeSafe(B_L, urlbuf);
}

/******************************************************************************/
/*      
 *      Output an error message and cleanup
 */

void websError(webs_t wp, int code, char_t *fmt, ...)
{
        va_list         args;
        char_t          *msg, *userMsg, *buf;

        a_assert(websValid(wp));
        a_assert(fmt);

        websStats.errors++;

        va_start(args, fmt);
        userMsg = NULL;
        gvsnprintf(&userMsg, WEBS_BUFSIZE, fmt, args);
        va_end(args);

        msg = T("<html><head><title>Document Error: %s</title></head>\r\n\
                <body><h2>Access Error: %s</h2>\r\n\
                when trying to obtain <b>%s</b><br><p>%s</p></body></html>\r\n");
/*
 *      Ensure we have plenty of room
 */
        buf = NULL;
        gsnprintf(&buf, WEBS_BUFSIZE, msg, websErrorMsg(code), 
                websErrorMsg(code), wp->url, userMsg);

        websResponse(wp, code, buf, NULL);
        bfreeSafe(B_L, buf);
        bfreeSafe(B_L, userMsg);
}

/******************************************************************************/
/*
 *      Return the error message for a given code
 */

static char_t *websErrorMsg(int code)
{
        websErrorType*  ep;

        for (ep = websErrors; ep->code; ep++) {
                if (code == ep->code) {
                        return ep->msg;
                }
        }
        a_assert(0);
        return T("");
}

/******************************************************************************/
/*
 *      Do formatted output to the browser. This is the public ASP and form
 *      write procedure.
 */

int websWrite(webs_t wp, char_t* fmt, ...)
{
        va_list          vargs;
        char_t          *buf;
        int                      rc;
        
        a_assert(websValid(wp));

        va_start(vargs, fmt);

        buf = NULL;
        rc = 0;
        if (gvsnprintf(&buf, WEBS_BUFSIZE, fmt, vargs) >= WEBS_BUFSIZE) {
                trace(0, T("webs: websWrite lost data, buffer overflow\n"));
        }
        va_end(vargs);
        a_assert(buf);
        if (buf) {
                rc = websWriteBlock(wp, buf, gstrlen(buf));
                bfree(B_L, buf);
        }
        return rc;
}

/******************************************************************************/
/*
 *      Write a block of data of length "nChars" to the user's browser. Public
 *      write block procedure.  If unicode is turned on this function expects 
 *      buf to be a unicode string and it converts it to ASCII before writing.
 *      See websWriteBlockData to always write binary or ASCII data with no 
 *      unicode conversion.  This returns the number of char_t's processed.
 */

int websWriteBlock(webs_t wp, char_t *buf, int nChars)
{
#if ! UNICODE
        return websWriteBlockData(wp, buf, nChars);
#else
        int             r;
        char    *charBuf;

        a_assert(buf);
        a_assert(nChars >= 0);

        if ((charBuf = ballocUniToAsc(buf, nChars)) == NULL) {
                return -1;
        }
        r = websWriteBlockData(wp, charBuf, nChars);
        bfree(B_L, charBuf);
        return r;
#endif
}

/******************************************************************************/
/*
 *      Write a block of data of length "nChars" to the user's browser. Same as
 *      websWriteBlock except that it expects straight ASCII or binary and does no
 *      unicode conversion before writing the data.
 *      This returns the number of chars processed.
 */

int websWriteBlockData(webs_t wp, char *buf, int nChars)
{
        int             len, done;

        a_assert(wp);
        a_assert(websValid(wp));
        a_assert(buf);
        a_assert(nChars >= 0);

        done = len = 0;
        while (nChars > 0) {
                if ((len = socketWrite(wp->sid, buf, nChars)) < 0) {
                        return -1;
                }
/*
 *              Block in flush if the last write could not take any more data
 */
                socketFlush(wp->sid, len == 0);
                nChars -= len;
                buf += len;
                done += len;
        }
        return done;
}

/******************************************************************************/
/*
 *      Decode a URL (or part thereof). Allows insitu decoding.
 */

void websDecodeUrl(char_t *decoded, char_t *token, int len)
{
        char_t  *ip,  *op;
        int             num, i, c;
        
        a_assert(decoded);
        a_assert(token);
        num = 0;

        op = decoded;
        for (ip = token; *ip && len > 0; ip++, op++) {
                if (*ip == '+') {
                        *op = ' ';
                } else if (*ip == '%' && gisxdigit(ip[1]) && gisxdigit(ip[2])) {

/*
 *                      Convert %nn to a single character
 */
                        ip++;
                        for (i = 0; i < 2; i++, ip++) {
                                c = tolower(*ip);
                                if (c >= 'a' && c <= 'f') {
                                        num = (num * 16) + 10 + c - 'a';
                                } else {
                                        num = (num * 16) + c - '0';
                                }
                        }
                        *op = (char_t) num;
                        ip--;

                } else {
                        *op = *ip;
                }
                len--;
        }
        *op = '\0';
}

/******************************************************************************/
#if WEBS_LOG_SUPPORT
/*
 *      Output a log message
 */

static void websLog(webs_t wp, int code)
{
        char_t  *buf;
        char    *abuf;
        int             len;

        a_assert(websValid(wp));

        buf = NULL;
        gsnprintf(&buf, WEBS_MAX_URL + 80, T("%d %s %d %d\n"), time(0), 
                wp->url, code, wp->written);
        len = gstrlen(buf);
        abuf = ballocUniToAsc(buf, len+1);
        write(websLogFd, abuf, len);
        bfreeSafe(B_L, buf);
        bfreeSafe(B_L, abuf);
}

#endif /* WEBS_LOG_SUPPORT */

/******************************************************************************/
/*
 *      Request timeout. The timeout triggers if we have not read any data from
 *      the users browser in the last WEBS_TIMEOUT period. If we have heard from
 *      the browser, simply re-issue the timeout.
 */

static void websTimeout(long iwp)
{
        webs_t          wp;
        int                     delay, tm;

        wp = (webs_t) iwp;
        a_assert(websValid(wp));

        tm = websGetTimeSinceMark(wp) * 1000;
        if (tm >= WEBS_TIMEOUT) {
                websStats.timeouts++;
                wp->timeout = NULL;
                websDone(wp, 404);

        } else {
                delay = WEBS_TIMEOUT - tm;
                a_assert(delay > 0);
                wp->timeout = emfCreateTimer(delay, websTimeout, (long) wp);
        }
}

/******************************************************************************/
/*
 *      Called when the request is done.
 */

void websDone(webs_t wp, int code)
{
        a_assert(websValid(wp));

/*
 *      Disable socket handler in case keep alive set.
 */
        socketDeleteHandler(wp->sid);

        if (code != 200) {
                wp->flags &= ~WEBS_KEEP_ALIVE;
        }

#if WEBS_PROXY_SUPPORT
        if (! (wp->flags & WEBS_LOCAL_PAGE)) {
                websStats.activeNetRequests--;
        }
#endif

#if WEBS_LOG_SUPPORT
        if (! (wp->flags & WEBS_REQUEST_DONE)) {
                websLog(wp, code);
        }
#endif

/*
 *      Close any opened document by a handler
 */
        websPageClose(wp);

/*
 *      If using Keep Alive (HTTP/1.1) we keep the socket open for a period
 *      while waiting for another request on the socket. 
 */
        if (wp->flags & WEBS_KEEP_ALIVE) {
                if (socketFlush(wp->sid, 0) == 0) {
                        wp->state = WEBS_BEGIN;
                        wp->flags |= WEBS_REQUEST_DONE;
                        if (wp->header.buf) {
                                ringqFlush(&wp->header);
                        }
                        socketCreateHandler(wp->sid, SOCKET_READABLE, websSocketEvent, 
                                (int) wp);
                        websTimeoutCancel(wp);
                        wp->timeout = emfCreateTimer(WEBS_TIMEOUT, websTimeout, (long) wp);
                        return;
                }
        } else {
                websTimeoutCancel(wp);
                socketCloseConnection(wp->sid);
        }
        websFree(wp);
}

/******************************************************************************/
/*
 *      Allocate a new webs structure
 */

static int websAlloc(int sid)
{
        webs_t          wp;
        int                     wid;

/*
 *      Allocate a new handle for this connection
 */
        if ((wid = hAllocEntry((void***) &webs, &websMax,
                        sizeof(struct websRec))) < 0) {
                return -1;
        }
        wp = webs[wid];

        wp->wid = wid;
        wp->sid = sid;
        wp->state = WEBS_BEGIN;
        wp->docfd = -1;
        wp->dir = NULL;

        ringqOpen(&wp->header, WEBS_HEADER_BUFINC, WEBS_MAX_HEADER);

/*
 *      Create storage for the CGI variables. We supply the symbol tables for
 *      both the CGI variables and for the global functions. The function table
 *      is common to all webs instances (ie. all browsers)
 */
        wp->cgiVars = symOpen(64);

        return wid;
}

/******************************************************************************/
/*
 *      Free a webs structure
 */

static void websFree(webs_t wp)
{
        a_assert(websValid(wp));

        if (wp->path)
                bfree(B_L, wp->path);
        if (wp->url)
                bfree(B_L, wp->url);
        if (wp->host)
                bfree(B_L, wp->host);
        if (wp->lpath)
                bfree(B_L, wp->lpath);
        if (wp->query)
                bfree(B_L, wp->query);
        if (wp->decodedQuery)
                bfree(B_L, wp->decodedQuery);
        if (wp->password)
                bfree(B_L, wp->password);
        if (wp->userName)
                bfree(B_L, wp->userName);
        if (wp->cookie)
                bfree(B_L, wp->cookie);
        if (wp->userAgent)
                bfree(B_L, wp->userAgent);
        if (wp->dir)
                bfree(B_L, wp->dir);

        symClose(wp->cgiVars, websFreeVar);

        if (wp->header.buf) {
                ringqClose(&wp->header);
        }

        websMax = hFree((void***) &webs, wp->wid);
        bfree(B_L, wp);
        a_assert(websMax >= 0);
}

/******************************************************************************/
/*
 *      Callback from symClose. Free the variable.
 */

static void websFreeVar(sym_t* sp)
{
        valueFree(&sp->content);
}

/******************************************************************************/
/*
 *      Return the server address
 */

char_t* websGetHost()
{
        return websHost;
}

/******************************************************************************/
/*
 *      Return the server address
 */

char_t* websGetHostUrl()
{
        return websHostUrl;
}

/******************************************************************************/
/*
 *      Return the listen port
 */

int websGetPort()
{
        return websPort;
}

/******************************************************************************/
/*
 *      Get the number of bytes to write
 */

int websGetRequestBytes(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->numbytes;
}

/******************************************************************************/
/*
 *      Get the directory for this request
 */

char_t *websGetRequestDir(webs_t wp)
{
        a_assert(websValid(wp));

        if (wp->dir == NULL) {
                return T("");
        }

        return wp->dir;
}

/******************************************************************************/
/*
 *      Get the flags for this request
 */

int websGetRequestFlags(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->flags;
}

/******************************************************************************/
/*
 *      Return the IP address
 */

char_t *websGetRequestIpaddr(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->ipaddr;
}

/******************************************************************************/
/*
 *      Set the local path for the request
 */

char_t *websGetRequestLpath(webs_t wp)
{
        a_assert(websValid(wp));

#if WEBS_PAGE_ROM
        return wp->path;
#else
        return wp->lpath;
#endif
}

/******************************************************************************/
/*
 *      Get the path for this request
 */

char_t *websGetRequestPath(webs_t wp)
{
        a_assert(websValid(wp));

        if (wp->path == NULL) {
                return T("");
        }

        return wp->path;
}

/******************************************************************************/
/*
 *      Return the password
 */

char_t* websGetRequestPassword(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->password;
}

/******************************************************************************/
/*
 *      Return the request type
 */

char_t* websGetRequestType(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->type;
}

/******************************************************************************/
/*
 *      Return the username
 */

char_t* websGetRequestUserName(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->userName;
}

/******************************************************************************/
/*
 *      Get the number of bytes written
 */

int websGetRequestWritten(webs_t wp)
{
        a_assert(websValid(wp));

        return wp->written;
}

/******************************************************************************/
/*
 *      Set the hostname
 */

void websSetHost(char_t *host)
{
        gstrncpy(websHost, host, TSZ(websHost));
}

/******************************************************************************/
/*
 *      Set the host URL
 */

void websSetHostUrl(char_t *url)
{
        a_assert(url && *url);

        bfreeSafe(B_L, websHostUrl);
        websHostUrl = gstrdup(B_L, url);
}

/******************************************************************************/
/*
 *      Set the IP address
 */

void websSetIpaddr(char_t *ipaddr)
{
        a_assert(ipaddr && *ipaddr);

        gstrncpy(websIpaddr, ipaddr, TSZ(websIpaddr));
}

/******************************************************************************/
/*
 *      Set the number of bytes to write
 */

void websSetRequestBytes(webs_t wp, int bytes)
{
        a_assert(websValid(wp));
        a_assert(bytes >= 0);

        wp->numbytes = bytes;
}

/******************************************************************************/
/*
 *      Set the flags for this request
 */

void websSetRequestFlags(webs_t wp, int flags)
{
        a_assert(websValid(wp));

        wp->flags = flags;
}

/******************************************************************************/
/*
 *      Set the local path for the request
 */

void websSetRequestLpath(webs_t wp, char_t *lpath)
{
        a_assert(websValid(wp));
        a_assert(lpath && *lpath);

        if (wp->lpath) {
                bfree(B_L, wp->lpath);
        }
        wp->lpath = bstrdup(B_L, lpath);
        websSetVar(wp, T("PATH_TRANSLATED"), wp->lpath);
}

/******************************************************************************/
/*
 *      Update the URL path and the directory containing the web page
 */

void websSetRequestPath(webs_t wp, char_t *dir, char_t *path)
{
        char_t  *tmp;

        a_assert(websValid(wp));

        if (dir) { 
                tmp = wp->dir;
                wp->dir = bstrdup(B_L, dir);
                if (tmp) {
                        bfree(B_L, tmp);
                }
        }
        if (path) {
                tmp = wp->path;
                wp->path = bstrdup(B_L, path);
                websSetVar(wp, T("PATH_INFO"), wp->path);
                if (tmp) {
                        bfree(B_L, tmp);
                }
        }
}

/******************************************************************************/
/*
 *      Set the Write handler for this socket
 */

void websSetRequestSocketHandler(webs_t wp, int mask, void (*fn)(webs_t wp))
{
        a_assert(websValid(wp));

        wp->writeSocket = fn;
        socketCreateHandler(wp->sid, SOCKET_WRITABLE, websSocketEvent, (int) wp);
}

/******************************************************************************/
/*
 *      Set the number of bytes written
 */

void websSetRequestWritten(webs_t wp, int written)
{
        a_assert(websValid(wp));

        wp->written = written;
}

/******************************************************************************/
/*
 *      Reurn true if the webs handle is valid
 */

int websValid(webs_t wp)
{
        int             wid;

        for (wid = 0; wid < websMax; wid++) {
                if (wp == webs[wid]) {
                        return 1;
                }
        }
        return 0;
}

/******************************************************************************/
/*
 *      Close the document handle.
 */

int websCloseFileHandle(webs_t wp)
{
        a_assert(websValid(wp));

#ifndef WEBS_PAGE_ROM
        if (wp->docfd >= 0) {
                close(wp->docfd);
                wp->docfd = -1;
        }
#endif

        return 0;
}

/******************************************************************************/
/*
 *      Build an ASCII time string.  If sbuf is NULL we use the current time,
 *      else we use the last modified time of sbuf;
 */

char_t* websGetDateString(websStatType* sbuf)
{
        char_t* cp;
        char_t* r;
        time_t  now;

        if (sbuf == NULL) {
                time(&now);
        } else {
                now = sbuf->mtime;
        }
        if ((cp = gctime(&now)) != NULL) {
                cp[gstrlen(cp) - 1] = '\0';
                r = bstrdup(B_L, cp);
                return r;
        }
        return NULL;
}

/******************************************************************************/
/*
 *      Mark time. Set a timestamp so that, later, we can return the number of
 *      seconds since we made the mark. Note that the mark my not be a
 *      "real" time, but rather a relative marker.
 */

static void websMarkTime(webs_t wp)
{
        wp->timestamp = time(0);
}

/******************************************************************************/
/*
 *      Get the number of seconds since the last mark.
 */

static int websGetTimeSinceMark(webs_t wp)
{
        return time(0) - wp->timestamp;
}

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