gui_www.c

/**
 * MojoSetup; a portable, flexible installation application.
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 *  This file written by Ryan C. Gordon.
 */

#if !SUPPORT_GUI_WWW
#error Something is wrong in the build system.
#endif

#define BUILDING_EXTERNAL_PLUGIN 1
#include "gui.h"

MOJOGUI_PLUGIN(www)

#if !GUI_STATIC_LINK_WWW
CREATE_MOJOGUI_ENTRY_POINT(www)
#endif

#include <stdarg.h>

#define FREE_AND_NULL(x) { free(x); x = NULL; }

// tapdance between things WinSock and BSD Sockets define differently...
#if PLATFORM_WINDOWS
    #include <winsock.h>

    typedef int socklen_t;

    #define setprotoent(x) assert(x == 0)
    #define sockErrno() WSAGetLastError()
    #define wouldBlockError(err) (err == WSAEWOULDBLOCK)
    #define intrError(err) (err == WSAEINTR)

    static inline void setBlocking(SOCKET s, boolean blocking)
    {
        u_long val = (blocking) ? 0 : 1;
        ioctlsocket(s, FIONBIO, &val);
    } // setBlocking

    static const char *sockStrErrVal(int val)
    {
        STUBBED("Windows strerror");
        return "sockStrErrVal() is unimplemented.";
    } // sockStrErrVal


    static boolean initSocketSupport(void)
    {
        WSADATA data;
        int rc = WSAStartup(MAKEWORD(1, 1), &data);
        if (rc != 0)
        {
            logError("www: WSAStartup() failed: %0", sockStrErrVal(rc));
            return false;
        } // if

        logInfo("www: WinSock initialized (want %0.%1, got %2.%3).",
                        numstr((int) (LOBYTE(data.wVersion))),
                        numstr((int) (HIBYTE(data.wVersion))),
                        numstr((int) (LOBYTE(data.wHighVersion))),
                        numstr((int) (HIBYTE(data.wHighVersion))));
        logInfo("www: WinSock description: %0", data.szDescription);
        logInfo("www: WinSock system status: %0", data.szSystemStatus);
        logInfo("www: WinSock max sockets: %0", numstr((int) data.iMaxSockets));

        return true;
    } // initSocketSupport

    #define deinitSocketSupport() WSACleanup()

#else
    #include <unistd.h>
    #include <errno.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <signal.h>
    #include <netdb.h>
    #include <fcntl.h>

    typedef int SOCKET;

    #define SOCKET_ERROR (-1)
    #define INVALID_SOCKET (-1)
    #define closesocket(x) close(x)
    #define sockErrno() (errno)
    #define sockStrErrVal(val) strerror(val)
    #define intrError(err) (err == EINTR)
    #define initSocketSupport() (true)
    #define deinitSocketSupport()

    static inline boolean wouldBlockError(int err)
    {
        return ((err == EWOULDBLOCK) || (err == EAGAIN));
    } // wouldBlockError

    static void setBlocking(SOCKET s, boolean blocking)
    {
        int flags = fcntl(s, F_GETFL, 0);
        if (blocking)
            flags &= ~O_NONBLOCK;
        else
            flags |= O_NONBLOCK;
        fcntl(s, F_SETFL, flags);
    } // setBlocking

#endif

#define sockStrError() (sockStrErrVal(sockErrno()))


typedef struct _S_WebRequest
{
    char *key;
    char *value;
    struct _S_WebRequest *next;
} WebRequest;


static char *output = NULL;
static char *lastProgressType = NULL;
static char *lastComponent = NULL;
static char *baseUrl = NULL;
static WebRequest *webRequest = NULL;
static uint32 percentTicks = 0;
static SOCKET listenSocket = INVALID_SOCKET;
static SOCKET clientSocket = INVALID_SOCKET;


static uint8 MojoGui_www_priority(boolean istty)
{
    return MOJOGUI_PRIORITY_TRY_LAST;
} // MojoGui_www_priority


static void freeWebRequest(void)
{
    while (webRequest)
    {
        WebRequest *next = webRequest->next;
        free(webRequest->key);
        free(webRequest->value);
        free(webRequest);
        webRequest = next;
    } // while
} // freeWebRequest


static void addWebRequest(const char *key, const char *val)
{
    if ((key != NULL) && (*key != '\0'))
    {
        WebRequest *req = (WebRequest *) xmalloc(sizeof (WebRequest));
        req->key = xstrdup(key);
        req->value = xstrdup(val);
        req->next = webRequest;
        webRequest = req;
        logDebug("www: request element '%0' = '%1'", key, val);
    } // if
} // addWebRequest


static int hexVal(char ch)
{
    if ((ch >= 'a') && (ch <= 'f'))
        return (ch - 'a') + 10;
    else if ((ch >= 'A') && (ch <= 'F'))
        return (ch - 'A') + 10;
    else if ((ch >= '0') && (ch <= '9'))
        return (ch - '0');
    return -1;
} // hexVal


static void unescapeUri(char *uri)
{
    char *ptr = uri;
    while ((ptr = strchr(ptr, '%')) != NULL)
    {
        int a, b;
        if ((a = hexVal(ptr[1])) != -1)
        {
            if ((b = hexVal(ptr[2])) != -1)
            {
                *(ptr++) = (char) ((a * 16) + b);
                memmove(ptr, ptr+2, strlen(ptr+1));
            } // if
            else
            {
                *(ptr++) = '?';
                memmove(ptr, ptr+1, strlen(ptr));
            } // else
        } // if
        else
        {
            *(ptr++) = '?';
        } // else
    } // while
} // unescapeUri


static int strAdd(char **ptr, size_t *len, size_t *alloc, const char *fmt, ...)
{
    size_t bw = 0;
    size_t avail = *alloc - *len;
    va_list ap;
    va_start(ap, fmt);
    bw = vsnprintf(*ptr + *len, avail, fmt, ap);
    va_end(ap);

    if (bw >= avail)
    {
        const size_t add = (*alloc + (bw + 1));  // double plus the new len.
        *alloc += add;
        avail += add;
        *ptr = xrealloc(*ptr, *alloc);
        va_start(ap, fmt);
        bw = vsnprintf(*ptr + *len, avail, fmt, ap);
        va_end(ap);
    } // if

    *len += bw;
    return bw;
} // strAdd


static char *htmlescape(const char *str)
{
    size_t len = 0, alloc = 0;
    char *retval = NULL;
    char ch;

    while ((ch = *(str++)) != '\0')
    {
        switch (ch)
        {
            case '&': strAdd(&retval, &len, &alloc, "&amp;"); break;
            case '<': strAdd(&retval, &len, &alloc, "&lt;"); break;
            case '>': strAdd(&retval, &len, &alloc, "&gt;"); break;
            case '"': strAdd(&retval, &len, &alloc, "&quot;"); break;
            case '\'': strAdd(&retval, &len, &alloc, "&#39;"); break;
            default: strAdd(&retval, &len, &alloc, "%c", ch); break;
        } // switch
    } // while

    return retval;
} // htmlescape


static const char *standardResponseHeaders =
    "Content-Type: text/html; charset=utf-8\n"
    "Accept-Ranges: none\n"
    "Cache-Control: no-cache\n"
    "Connection: close\n\n";


static void setHtmlString(char **str, int responseCode,
                          const char *responseString,
                          const char *title, const char *html)
{
    size_t len = 0, alloc = 0;
    FREE_AND_NULL(*str);
    strAdd(str, &len, &alloc,
              "HTTP/1.1 %d %s\n"   // responseCode, responseString
              "%s"  // standardResponseHeaders
              "<html>"
               "<head>"
                "<title>%s</title>"  // title
               "</head>"
               "<body>%s</body>"  // html
              "</html>\n",
           responseCode, responseString,
           standardResponseHeaders,
           title, html);
} // setHtmlString


static void setHtml(const char *title, const char *html)
{
    setHtmlString(&output, 200, "OK", title, html);
} // setHtml


static void sendStringAndDrop(SOCKET *_s, const char *str)
{
    SOCKET s = *_s;
    int outlen = 0;
    if (str == NULL)
        str = "";
    else
        outlen = strlen(str);

    setBlocking(s, true);

    while (outlen > 0)
    {
        int rc = send(s, str, outlen, 0);
        if (rc != SOCKET_ERROR)
        {
            str += rc;
            outlen -= rc;
        } // if
        else
        {
            const int err = sockErrno();
            if (!intrError(err))
            {
                logError("www: send() failed: %0", sockStrErrVal(err));
                break;
            } // if
        } // else
    } // while

    closesocket(s);
    *_s = INVALID_SOCKET;
} // sendStringAndDrop


static void respond404(SOCKET *s)
{
    char *text = htmlescape(_("Not Found"));
    char *str = NULL;
    size_t len = 0, alloc = 0;
    char *html = NULL;
    strAdd(&html, &len, &alloc, "<center><h1>%s</h1></center>", text);
    setHtmlString(&str, 404, text, text, html);
    free(html);
    free(text);
    sendStringAndDrop(s, str);
    free(str);
} // respond404


static boolean parseGet(char *get)
{
    char *uri = NULL;
    char *ver = NULL;

    uri = strchr(get, ' ');
    if (uri == NULL) return false;
    *(uri++) = '\0';

    ver = strchr(uri, ' ');
    if (ver == NULL) return false;
    *(ver++) = '\0';

    if (strcmp(get, "GET") != 0) return false;
    if (uri[0] != '/') return false;
    uri++;  // skip dirsep.

    // !!! FIXME: we may want to feed stock files (<img> tags, etc)
    // !!! FIXME:  at some point in the future.
    if ((uri[0] != '?') && (uri[0] != '\0')) return false;
    if (strncmp(ver, "HTTP/", 5) != 0) return false;

    if (*uri == '?')
        uri++;  // skip initial argsep.

    do
    {
        char *next = strchr(uri, '&');
        char *val = NULL;
        if (next != NULL)
            *(next++) = '\0';

        val = strchr(uri, '=');
        if (val == NULL)
            val = "";
        else
            *(val++) = '\0';

        unescapeUri(uri);
        unescapeUri(val);
        addWebRequest(uri, val);

        uri = next;
    } while (uri != NULL);

    return true;
} // parseGet


static boolean parseRequest(char *reqstr)
{
    do
    {
        char *next = strchr(reqstr, '\n');
        char *val = NULL;
        if (next != NULL)
            *(next++) = '\0';

        val = strchr(reqstr, ':');
        if (val == NULL)
            val = "";
        else
        {
            *(val++) = '\0';
            while (*val == ' ')
                val++;
        } // else

        if (*reqstr != '\0')
        {
            size_t len = 0, alloc = 0;
            char *buf = NULL;
            strAdd(&buf, &len, &alloc, "HTTP-%s", reqstr);
            addWebRequest(buf, val);
            free(buf);
        } // if

        reqstr = next;
    } while (reqstr != NULL);

    return true;
} // parseRequest


static WebRequest *servePage(boolean blocking)
{
    int newline = 0;
    char ch = 0;
    struct sockaddr_in addr;
    socklen_t addrlen = 0;
    int s = 0;
    char *reqstr = NULL;
    size_t len = 0, alloc = 0;
    int err = 0;

    freeWebRequest();

    if (listenSocket == INVALID_SOCKET)
        return NULL;

    if (clientSocket != INVALID_SOCKET)  // response to feed to client.
        sendStringAndDrop(&clientSocket, output);

    if (blocking)
        setBlocking(listenSocket, true);

    do
    {
        s = accept(listenSocket, (struct sockaddr *) &addr, &addrlen);
        err = sockErrno();
    } while ( (s == INVALID_SOCKET) && (intrError(err)) );

    if (blocking)
        setBlocking(listenSocket, false);  // reset what we toggled up there.

    if (s == INVALID_SOCKET)
    {
        if (wouldBlockError(err))
            assert(!blocking);
        else
        {
            logError("www: accept() failed: %0", sockStrErrVal(err));
            closesocket(listenSocket);  // make all future i/o fail too.
            listenSocket = INVALID_SOCKET;
        } // else
        return NULL;
    } // if

    setBlocking(s, true);

    // Doing this one char at a time isn't efficient, but it's easy.

    while (1)
    {
        if (recv(s, &ch, 1, 0) == SOCKET_ERROR)
        {
            const int err = sockErrno();
            if (!intrError(err))  // just try again on interrupt.
            {
                logError("www: recv() failed: %0", sockStrErrVal(err));
                FREE_AND_NULL(reqstr);
                closesocket(s);
                s = INVALID_SOCKET;
                break;
            } // if
        } // if

        else if (ch == '\n')  // newline
        {
            if (++newline == 2)
                break;  // end of request.
            strAdd(&reqstr, &len, &alloc, "\n");
        } // if

        else if (ch != '\r')
        {
            newline = 0;
            strAdd(&reqstr, &len, &alloc, "%c", ch);
        } // else if
    } // while

    if (reqstr != NULL)
    {
        char *get = NULL;
        char *ptr = strchr(reqstr, '\n');
        if (ptr != NULL)
        {
            *ptr = '\0';
            ptr++;
        } // if

        // reqstr is the GET (or whatever) request, ptr is the rest.
        get = xstrdup(reqstr);
        if (ptr == NULL)
        {
            *ptr = '\0';
            len = 0;
        } // if
        else
        {
            len = strlen(ptr);
            memmove(reqstr, ptr, len+1);
        } // else

        logDebug("www: request '%0'", get);

        // okay, now (get) and (reqptr) are separate strings.
        // These parse*() functions update (webRequest).
        if ( (parseGet(get)) && (parseRequest(reqstr)) )
            logDebug("www: accepted request");
        else
        {
            logError("www: rejected bogus request");
            freeWebRequest();
            respond404(&s);
        } // else

        free(reqstr);
        free(get);
    } // if

    clientSocket = s;
    return webRequest;
} // servePage


static SOCKET create_listen_socket(short portnum)
{
    SOCKET s = INVALID_SOCKET;
    int protocol = 0;  // pray this is right.
    struct protoent *prot;

    setprotoent(0);
    prot = getprotobyname("tcp");
    if (prot != NULL)
        protocol = prot->p_proto;

    s = socket(PF_INET, SOCK_STREAM, protocol);
    if (s == INVALID_SOCKET)
        logInfo("www: socket() failed ('%0')", sockStrError());
    else
    {
        boolean success = false;
        struct sockaddr_in addr;
        addr.sin_family = AF_INET;
        addr.sin_port = htons(portnum);
        addr.sin_addr.s_addr = INADDR_ANY;  // !!! FIXME: bind to localhost.

        // So we can bind this socket over and over in debug runs...
        #if ((!defined _NDEBUG) && (!defined NDEBUG))
        {
            int on = 1;
            setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*) &on, sizeof (on));
        }
        #endif

        if (bind(s, (struct sockaddr *) &addr, sizeof (addr)) == SOCKET_ERROR)
            logError("www: bind() failed ('%0')", sockStrError());
        else if (listen(s, 5) == SOCKET_ERROR)
            logError("www: listen() failed ('%0')", sockStrError());
        else
        {
            logInfo("www: socket created on port %0",
                           numstr(portnum));
            success = true;
        } // else

        if (!success)
        {
            closesocket(s);
            s = INVALID_SOCKET;
        } // if
    } // if

    return s;
} // create_listen_socket


static boolean MojoGui_www_init(void)
{
    size_t len = 0, alloc = 0;
    short portnum = 7341;  // !!! FIXME: try some random ports.
    percentTicks = 0;

    if (!initSocketSupport())
    {
        logInfo("www: socket subsystem init failed, use another UI.");
        return false;
    } // if
    
    listenSocket = create_listen_socket(portnum);
    if (listenSocket < 0)
    {
        logInfo("www: no listen socket, use another UI.");
        return false;
    } // if

    setBlocking(listenSocket, false);

    strAdd(&baseUrl, &len, &alloc, "http://localhost:%d/", (int) portnum);
    return true;
} // MojoGui_www_init


static void MojoGui_www_deinit(void)
{
    // Catch any waiting browser connections...and tell them to buzz off!  :)
    char *donetitle = htmlescape(_("Shutting down..."));
    char *donetext = htmlescape(_("You can close this browser now."));
    size_t len = 0, alloc = 0;
    char *html = NULL;

    strAdd(&html, &len, &alloc, "<hr><center>%s</center><hr>", donetext);
    setHtml(donetitle, html);
    free(html);
    free(donetitle);
    free(donetext);
    while (servePage(false) != NULL) { /* no-op. */ }

    freeWebRequest();
    FREE_AND_NULL(output);
    FREE_AND_NULL(lastProgressType);
    FREE_AND_NULL(lastComponent);
    FREE_AND_NULL(baseUrl);

    if (clientSocket != INVALID_SOCKET)
    {
        closesocket(clientSocket);
        clientSocket = INVALID_SOCKET;
    } // if

    if (listenSocket != INVALID_SOCKET)
    {
        closesocket(listenSocket);
        listenSocket = INVALID_SOCKET;
    } // if

    deinitSocketSupport();
} // MojoGui_www_deinit


static int doPromptPage(const char *title, const char *text, boolean centertxt,
                        const char *pagename,
                        const char **buttons, const char **locButtons,
                        int bcount)
{
    char *htmltitle = htmlescape(title);
    boolean sawPage = false;
    int answer = -1;
    int i = 0;
    char *html = NULL;
    size_t len = 0, alloc = 0;
    const char *align = ((centertxt) ? " align='center'" : "");

    strAdd(&html, &len, &alloc,
        "<center>"
        "<form name='form_%s' method='get'>"  // pagename
         "<input type='hidden' name='page' value='%s'>"  // pagename
         "<table>"
          "<tr><td%s>%s</td></tr>"   // align, text
          "<tr>"
           "<td align='center'>", pagename, pagename, align, text);

    for (i = 0; i < bcount; i++)
    {
        const char *button = buttons[i];
        const char *loc = locButtons[i];
        strAdd(&html, &len, &alloc,
            "<input type='submit' name='%s' value='%s'>", button, loc);
    } // for

    strAdd(&html, &len, &alloc,
           "</td>"
          "</tr>"
         "</table>"
        "</form>"
        "</center>");

    setHtml(htmltitle, html);
    free(htmltitle);
    free(html);

    while ((!sawPage) || (answer == -1))
    {
        WebRequest *req = servePage(true);
        sawPage = false;
        answer = -1;
        while (req != NULL)
        {
            const char *k = req->key;
            const char *v = req->value;
            if ( (strcmp(k, "page") == 0) && (strcmp(v, pagename) == 0) )
                sawPage = true;
            else
            {
                for (i = 0; i < bcount; i++)
                {
                    if (strcmp(k, buttons[i]) == 0)
                    {
                        answer = i;
                        break;
                    } // if
                } // for
            } // else

            req = req->next;
        } // while
    } // while

    return answer;
} // doPromptPage


static void MojoGui_www_msgbox(const char *title, const char *text)
{
    const char *buttons[] = { "ok" };
    const char *locButtons[] = { htmlescape(_("OK")) };
    char *htmltext = htmlescape(text);
    doPromptPage(title, htmltext, true, "msgbox", buttons, locButtons, 1);
    free(htmltext);
    free((void *) locButtons[0]);
} // MojoGui_www_msgbox


static boolean MojoGui_www_promptyn(const char *title, const char *text,
                                    boolean defval)
{
    // !!! FIXME:
    // We currently ignore defval

    int i, rc;
    char *htmltext = htmlescape(text);
    const char *buttons[] = { "no", "yes" };
    const char *locButtons[] = { htmlescape(_("No")), htmlescape(_("Yes")) };

    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    rc = doPromptPage(title, htmltext, true, "promptyn", buttons, locButtons,
                      STATICARRAYLEN(buttons));
    free(htmltext);

    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    return (rc == 1);
} // MojoGui_www_promptyn


static MojoGuiYNAN MojoGui_www_promptynan(const char *title, const char *text,
                                          boolean defval)
{
    // !!! FIXME:
    // We currently ignore defval

    int i, rc;
    char *htmltext = htmlescape(text);
    const char *buttons[] = { "no", "yes", "always", "never" };
    const char *locButtons[] = {
        htmlescape(_("No")),
        htmlescape(_("Yes")),
        htmlescape(_("Always")),
        htmlescape(_("Never")),
    };
    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    rc = doPromptPage(title, htmltext, true, "promptynan", buttons, locButtons,
                      STATICARRAYLEN(buttons));

    free(htmltext);
    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    return (MojoGuiYNAN) rc;
} // MojoGui_www_promptynan


static boolean MojoGui_www_start(const char *title,
                                 const MojoGuiSplash *splash)
{
    return true;
} // MojoGui_www_start


static void MojoGui_www_stop(void)
{
    // no-op.
} // MojoGui_www_stop


static int MojoGui_www_readme(const char *name, const uint8 *data,
                              size_t datalen, boolean can_back,
                              boolean can_fwd)
{
    char *text = NULL;
    size_t len = 0, alloc = 0;
    char *htmldata = htmlescape((const char *) data);
    int i, rc;
    int cancelbutton = -1;
    int backbutton = -1;
    int fwdbutton = -1;
    int bcount = 0;
    const char *buttons[4] = { NULL, NULL, NULL, NULL };
    const char *locButtons[4] = { NULL, NULL, NULL, NULL };
    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    cancelbutton = bcount++;
    buttons[cancelbutton] = "cancel";
    locButtons[cancelbutton] = xstrdup(_("Cancel"));

    if (can_back)
    {
        backbutton = bcount++;
        buttons[backbutton] = "back";
        locButtons[backbutton] = xstrdup(_("Back"));
    } // if

    if (can_fwd)
    {
        fwdbutton = bcount++;
        buttons[fwdbutton] = "next";
        locButtons[fwdbutton] = xstrdup(_("Next"));
    } // if

    strAdd(&text, &len, &alloc, "<pre>\n%s\n</pre>", htmldata);
    free(htmldata);

    rc = doPromptPage(name, text, false, "readme", buttons, locButtons, bcount);

    free(text);
    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    if (rc == backbutton)
        return -1;
    else if (rc == cancelbutton)
        return 0;
    return 1;
} // MojoGui_www_readme


static int MojoGui_www_options(MojoGuiSetupOptions *opts,
                               boolean can_back, boolean can_fwd)
{
    // !!! FIXME: write me.
    STUBBED("www options");
    return 1;
} // MojoGui_www_options


static char *MojoGui_www_destination(const char **recommends, int recnum,
                                     int *command, boolean can_back,
                                     boolean can_fwd)
{
    char *retval = NULL;
    char *title = xstrdup(_("Destination"));
    char *html = NULL;
    size_t len = 0, alloc = 0;
    boolean checked = true;
    int cancelbutton = -1;
    int backbutton = -1;
    int fwdbutton = -1;
    int bcount = 0;
    int rc = 0;
    int i = 0;
    const char *buttons[4] = { NULL, NULL, NULL, NULL };
    const char *locButtons[4] = { NULL, NULL, NULL, NULL };
    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    cancelbutton = bcount++;
    buttons[cancelbutton] = "cancel";
    locButtons[cancelbutton] = xstrdup(_("Cancel"));

    if (can_back)
    {
        backbutton = bcount++;
        buttons[backbutton] = "back";
        locButtons[backbutton] = xstrdup(_("Back"));
    } // if

    if (can_fwd)
    {
        fwdbutton = bcount++;
        buttons[fwdbutton] = "next";
        locButtons[fwdbutton] = xstrdup(_("Next"));
    } // if

    strAdd(&html, &len, &alloc,
        "<form name='form_destination' method='get'>"
          "<table>");

    for (i = 0; i < recnum; i++)
    {
        strAdd(&html, &len, &alloc,
           "<tr>"
            "<td>"
             "<input type='radio' name='dest' %s value='%s'>%s"
            "</td>"
           "</tr>",
            ((checked) ? "checked='true'" : ""), recommends[i], recommends[i]);
        checked = false;
    } // for

    strAdd(&html, &len, &alloc,
           "<tr>"
            "<td>"
             "<input type='radio' name='dest' %s value='*'>"
             "<input type='text' name='customdest' value=''>"
            "</td>"
           "</tr>"
          "</table>"
         "</form>", ((checked) ? "checked='true'" : ""));

    rc = doPromptPage(title, html, true, "destination",
                      buttons, locButtons, bcount);

    free(title);
    free(html);
    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    if (rc == backbutton)
        *command = -1;
    else if (rc == cancelbutton)
        *command = 0;
    else
    {
        const char *dest = NULL;
        const char *customdest = NULL;
        WebRequest *req = webRequest;
        while (req != NULL)
        {
            const char *k = req->key;
            const char *v = req->value;
            if (strcmp(k, "dest") == 0)
                dest = v;
            else if (strcmp(k, "customdest") == 0)
                customdest = v;
            req = req->next;
        } // while

        if (dest != NULL)
        {
            if (strcmp(dest, "*") == 0)
                dest = customdest;
        } // if

        if (dest == NULL)
            *command = 0;   // !!! FIXME: maybe loop with doPromptPage again.
        else
        {
            retval = xstrdup(dest);
            *command = 1;
        } // else
    } // else

    return retval;
} // MojoGui_www_destination


static int MojoGui_www_productkey(const char *desc, const char *fmt,
                                  char *buf, const int buflen,
                                  boolean can_back, boolean can_fwd)
{
    const char *prompt = xstrdup(_("Please enter your product key"));
    char *retval = NULL;
    char *html = NULL;
    size_t len = 0, alloc = 0;
    boolean checked = true;
    int cancelbutton = -1;
    int backbutton = -1;
    int fwdbutton = -1;
    int bcount = 0;
    int rc = 0;
    int i = 0;
    const char *buttons[4] = { NULL, NULL, NULL, NULL };
    const char *locButtons[4] = { NULL, NULL, NULL, NULL };
    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    cancelbutton = bcount++;
    buttons[cancelbutton] = "cancel";
    locButtons[cancelbutton] = xstrdup(_("Cancel"));

    if (can_back)
    {
        backbutton = bcount++;
        buttons[backbutton] = "back";
        locButtons[backbutton] = xstrdup(_("Back"));
    } // if

    if (can_fwd)
    {
        fwdbutton = bcount++;
        buttons[fwdbutton] = "next";
        locButtons[fwdbutton] = xstrdup(_("Next"));
    } // if

    strAdd(&html, &len, &alloc,
        "<form name='form_productkey' method='get'>"
          "%s<br/>"
          "<input type='text' name='productkey' value='%s'>"
         "</form>", prompt, ((*buf) ? buf : ""));

    free(prompt);

    rc = doPromptPage(desc, html, true, "productkey",
                      buttons, locButtons, bcount);

    free(html);
    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    if (rc == backbutton)
        retval = -1;
    else if (rc == cancelbutton)
        retval = 0;
    else
    {
        WebRequest *req = webRequest;
        const char *keyval = NULL;
        while (req != NULL)
        {
            const char *k = req->key;
            const char *v = req->value;
            if (strcmp(k, "productkey") == 0)
                keyval = v;

            req = req->next;
        } // while

        if (keyval == NULL)
            retval = 0;   // !!! FIXME: maybe loop with doPromptPage again.
        else
        {
            snprintf(buf, buflen, "%s", keyval);
            if (isValidProductKey(fmt, buf))
                retval = 1;
            // !!! FIXME: must try again if invalid key.
        } // else
    } // else

    return retval;
} // MojoGui_www_productkey


static boolean MojoGui_www_insertmedia(const char *medianame)
{
    char *htmltext = NULL;
    char *text = NULL;
    size_t len = 0, alloc = 0;
    int i, rc;

    const char *buttons[] = { "cancel", "ok" };
    const char *locButtons[] = { htmlescape(_("Cancel")), htmlescape(_("OK")) };

    char *title = xstrdup(_("Media change"));
    char *fmt = xstrdup(_("Please insert '%0'"));
    char *msg = format(fmt, medianame);
    strAdd(&text, &len, &alloc, msg);
    free(msg);
    free(fmt);

    htmltext = htmlescape(text);
    free(text);

    assert(STATICARRAYLEN(buttons) == STATICARRAYLEN(locButtons));

    rc = doPromptPage(title, htmltext, true, "insertmedia", buttons,
                      locButtons, STATICARRAYLEN(buttons));

    free(title);
    free(htmltext);
    for (i = 0; i < STATICARRAYLEN(locButtons); i++)
        free((void *) locButtons[i]);

    return (rc == 1);
} // MojoGui_www_insertmedia


static void MojoGui_www_progressitem(void)
{
    // no-op in this UI target.
} // MojoGui_www_progressitem


static boolean MojoGui_www_progress(const char *type, const char *component,
                                    int percent, const char *item,
                                    boolean can_cancel)
{
    return true;
} // MojoGui_www_progress


static void MojoGui_www_final(const char *msg)
{
    MojoGui_www_msgbox(_("Finish"), msg);
} // MojoGui_www_final

// end of gui_www.c ...