x11vnc/selection.c

/*
   Copyright (C) 2002-2010 Karl J. Runge <runge@karlrunge.com> 
   All rights reserved.

This file is part of x11vnc.

x11vnc is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

x11vnc is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with x11vnc; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA
or see <http://www.gnu.org/licenses/>.

In addition, as a special exception, Karl J. Runge
gives permission to link the code of its release of x11vnc with the
OpenSSL project's "OpenSSL" library (or with modified versions of it
that use the same license as the "OpenSSL" library), and distribute
the linked executables.  You must obey the GNU General Public License
in all respects for all of the code used other than "OpenSSL".  If you
modify this file, you may extend this exception to your version of the
file, but you are not obligated to do so.  If you do not wish to do
so, delete this exception statement from your version.
*/

/* -- selection.c -- */

#include "x11vnc.h"
#include "cleanup.h"
#include "connections.h"
#include "unixpw.h"
#include "win_utils.h"
#include "xwrappers.h"

/*
 * Selection/Cutbuffer/Clipboard handlers.
 */

int own_primary = 0;	/* whether we currently own PRIMARY or not */
int set_primary = 1;
int own_clipboard = 0;	/* whether we currently own CLIPBOARD or not */
int set_clipboard = 1;
int set_cutbuffer = 0;	/* to avoid bouncing the CutText right back */
int sel_waittime = 15;	/* some seconds to skip before first send */
Window selwin = None;	/* special window for our selection */
Atom clipboard_atom = None;

/*
 * This is where we keep our selection: the string sent TO us from VNC
 * clients, and the string sent BY us to requesting X11 clients.
 */
char *xcut_str_primary = NULL;
char *xcut_str_clipboard = NULL;


void selection_request(XEvent *ev, char *type);
int check_sel_direction(char *dir, char *label, char *sel, int len);
void cutbuffer_send(void);
void selection_send(XEvent *ev);
void resend_selection(char *type);


/*
 * Our callbacks instruct us to check for changes in the cutbuffer
 * and PRIMARY and CLIPBOARD selection on the local X11 display.
 *
 * TODO: check if malloc does not cause performance issues (esp. WRT
 * SelectionNotify handling).
 */
static char cutbuffer_str[PROP_MAX+1];
static char primary_str[PROP_MAX+1];
static char clipboard_str[PROP_MAX+1];
static int cutbuffer_len = 0;
static int primary_len   = 0;
static int clipboard_len = 0;

/*
 * An X11 (not VNC) client on the local display has requested the selection
 * from us (because we are the current owner).
 *
 * n.b.: our caller already has the X_LOCK.
 */
void selection_request(XEvent *ev, char *type) {
#if NO_X11
	RAWFB_RET_VOID
	if (!ev || !type) {}
	return;
#else
	XSelectionEvent notify_event;
	XSelectionRequestEvent *req_event;
	XErrorHandler old_handler;
	char *str;
	unsigned int length;
	unsigned char *data;
	static Atom xa_targets = None;
	static int sync_it = -1;
# ifndef XA_LENGTH
	unsigned long XA_LENGTH;
# endif
	RAWFB_RET_VOID

# ifndef XA_LENGTH
	XA_LENGTH = XInternAtom(dpy, "LENGTH", True);
# endif

	if (sync_it < 0) {
		if (getenv("X11VNC_SENDEVENT_SYNC")) {
			sync_it = 1;
		} else {
			sync_it = 0;
		}
	}

	req_event = &(ev->xselectionrequest);
	notify_event.type 	= SelectionNotify;
	notify_event.display	= req_event->display;
	notify_event.requestor	= req_event->requestor;
	notify_event.selection	= req_event->selection;
	notify_event.target	= req_event->target;
	notify_event.time	= req_event->time;

	if (req_event->property == None) {
		notify_event.property = req_event->target;
	} else {
		notify_event.property = req_event->property;
	}

	if (!strcmp(type, "PRIMARY")) {
		str = xcut_str_primary;
	} else if (!strcmp(type, "CLIPBOARD")) {
		str = xcut_str_clipboard;
	} else {
		return;
	}
	if (str) {
		length = strlen(str);
	} else {
		length = 0;
	}
	if (debug_sel) {
		rfbLog("%s\trequest event:   owner=0x%x requestor=0x%x sel=%03d targ=%d prop=%d\n",
			type, req_event->owner, req_event->requestor, req_event->selection,
			req_event->target, req_event->property);
	}

	if (xa_targets == None) {
		xa_targets = XInternAtom(dpy, "TARGETS", False);
	}

	/* the window may have gone away, so trap errors */
	trapped_xerror = 0;
	old_handler = XSetErrorHandler(trap_xerror);

	if (ev->xselectionrequest.target == XA_LENGTH) {
		/* length request */
		int ret;
		long llength = (long) length;

		ret = XChangeProperty(ev->xselectionrequest.display,
		    ev->xselectionrequest.requestor,
		    ev->xselectionrequest.property,
		    ev->xselectionrequest.target, 32, PropModeReplace,
		    (unsigned char *) &llength, 1);	/* had sizeof(unsigned int) = 4 before... */
		if (debug_sel) {
			rfbLog("LENGTH: XChangeProperty() -> %d\n", ret);
		}

	} else if (xa_targets != None && ev->xselectionrequest.target == xa_targets) {
		/* targets request */
		int ret;
		Atom targets[2];
		targets[0] = (Atom) xa_targets;
		targets[1] = (Atom) XA_STRING;

		ret = XChangeProperty(ev->xselectionrequest.display,
		    ev->xselectionrequest.requestor,
		    ev->xselectionrequest.property,
		    ev->xselectionrequest.target, 32, PropModeReplace,
		    (unsigned char *) targets, 2);
		if (debug_sel) {
			rfbLog("TARGETS: XChangeProperty() -> %d -- sz1: %d  sz2: %d\n",
			    ret, sizeof(targets[0]), sizeof(targets)/sizeof(targets[0]));
		}

	} else {
		/* data request */
		int ret;

		data = (unsigned char *)str;

		ret = XChangeProperty(ev->xselectionrequest.display,
		    ev->xselectionrequest.requestor,
		    ev->xselectionrequest.property,
		    ev->xselectionrequest.target, 8, PropModeReplace,
		    data, length);
		if (debug_sel) {
			rfbLog("DATA: XChangeProperty() -> %d\n", ret);
		}
	}

	if (! trapped_xerror) {
		int ret = -2, skip_it = 0, ms = 0;
		double now = dnow();
		static double last_check = 0.0;

		if (now > last_check + 0.2) {
			XFlush_wr(dpy);
			if (!valid_window(req_event->requestor , NULL, 1)) {
				sync_it = 1;
				skip_it = 1;
				if (debug_sel) {
					rfbLog("selection_request: not a valid window: 0x%x\n",
					    req_event->requestor);
				}
				ms = 10;
			}
			if (trapped_xerror) {
				sync_it = 1;
				skip_it = 1;
			}
			last_check = dnow();
		}

		if (!skip_it) {
			ret = XSendEvent(req_event->display, req_event->requestor, False, 0,
			    (XEvent *)&notify_event);
		}
		if (debug_sel) {
			rfbLog("XSendEvent() -> %d\n", ret);
		}
		if (ms > 0) {
			usleep(ms * 1000);
		}
	}
	if (trapped_xerror) {
		rfbLog("selection_request: ignored XError while sending "
		    "%s selection to 0x%x.\n", type, req_event->requestor);
	}

	XFlush_wr(dpy);
	if (sync_it) {
		usleep(10 * 1000);
		XSync(dpy, False);
	}

	XSetErrorHandler(old_handler);
	trapped_xerror = 0;

#endif	/* NO_X11 */
}

int check_sel_direction(char *dir, char *label, char *sel, int len) {
	int db = 0, ok = 1;
	if (debug_sel) {
		db = 1;
	}
	if (sel_direction) {
		if (strstr(sel_direction, "debug")) {
			db = 1;
		}
		if (strcmp(sel_direction, "debug")) {
			if (strstr(sel_direction, dir) == NULL) {
				ok = 0;
			}
		}
	}
	if (db) {
		char str[40];
		int n = 40;
		strncpy(str, sel, n);
		str[n-1] = '\0';
		if (len < n) {
			str[len] = '\0';
		}
		rfbLog("%s: '%s'\n", label, str);
		if (ok) {
			rfbLog("%s: %s-ing it.\n", label, dir);
		} else {
			rfbLog("%s: NOT %s-ing it.\n", label, dir);
		}
	}
	return ok;
}

/*
 * CUT_BUFFER0 property on the local display has changed, we read and
 * store it and send it out to any connected VNC clients.
 *
 * n.b.: our caller already has the X_LOCK.
 */
void cutbuffer_send(void) {
#if NO_X11
	RAWFB_RET_VOID
	return;
#else
	Atom type;
	int format, slen, dlen, len;
	unsigned long nitems = 0, bytes_after = 0;
	unsigned char* data = NULL;

	cutbuffer_str[0] = '\0';
	slen = 0;

	RAWFB_RET_VOID

	/* read the property value into cutbuffer_str: */
	do {
		if (XGetWindowProperty(dpy, DefaultRootWindow(dpy),
		    XA_CUT_BUFFER0, nitems/4, PROP_MAX/16, False,
		    AnyPropertyType, &type, &format, &nitems, &bytes_after,
		    &data) == Success) {

			dlen = nitems * (format/8);
			if (slen + dlen > PROP_MAX) {
				/* too big */
				rfbLog("warning: truncating large CUT_BUFFER0"
				   " selection > %d bytes.\n", PROP_MAX);
				XFree_wr(data);
				break;
			}
			memcpy(cutbuffer_str+slen, data, dlen);
			slen += dlen;
			cutbuffer_str[slen] = '\0';
			XFree_wr(data);
		}
	} while (bytes_after > 0);

	cutbuffer_str[PROP_MAX] = '\0';

	if (debug_sel) {
		rfbLog("cutbuffer_send: '%s'\n", cutbuffer_str);
	}

	if (! all_clients_initialized()) {
		rfbLog("cutbuffer_send: no send: uninitialized clients\n");
		return; /* some clients initializing, cannot send */ 
	}
	if (unixpw_in_progress) {
		return;
	}

	/* now send it to any connected VNC clients (rfbServerCutText) */
	if (!screen) {
		return;
	}
	cutbuffer_len = len = strlen(cutbuffer_str);
	if (check_sel_direction("send", "cutbuffer_send", cutbuffer_str, len)) {
		rfbSendServerCutText(screen, cutbuffer_str, len);
	}
#endif	/* NO_X11 */
}

/* 
 * "callback" for our SelectionNotify polling.  We try to determine if
 * the PRIMARY selection has changed (checking length and first CHKSZ bytes)
 * and if it has we store it and send it off to any connected VNC clients.
 *
 * n.b.: our caller already has the X_LOCK.
 *
 * TODO: if we were willing to use libXt, we could perhaps get selection
 * timestamps to speed up the checking... XtGetSelectionValue().
 *
 * Also: XFIXES has XFixesSelectSelectionInput().
 */
#define CHKSZ 32

void selection_send(XEvent *ev) {
#if NO_X11
	RAWFB_RET_VOID
	if (!ev) {}
	return;
#else
	Atom type;
	int format, slen, dlen, oldlen, newlen, toobig = 0, len;
	static int err = 0, sent_one = 0;
	char before[CHKSZ], after[CHKSZ];
	unsigned long nitems = 0, bytes_after = 0;
	unsigned char* data = NULL;
	char *selection_str;

	RAWFB_RET_VOID
	/*
	 * remember info about our last value of PRIMARY (or CUT_BUFFER0)
	 * so we can check for any changes below.
	 */
	if (ev->xselection.selection == XA_PRIMARY) {
		if (! watch_primary) {
			return;
		}
		selection_str = primary_str;
		if (debug_sel) {
			rfbLog("selection_send: event PRIMARY   prop: %d  requestor: 0x%x  atom: %d\n",
			    ev->xselection.property, ev->xselection.requestor, ev->xselection.selection);
		}
	} else if (clipboard_atom && ev->xselection.selection == clipboard_atom)  {
		if (! watch_clipboard) {
			return;
		}
		selection_str = clipboard_str;
		if (debug_sel) {
			rfbLog("selection_send: event CLIPBOARD prop: %d  requestor: 0x%x atom: %d\n",
			    ev->xselection.property, ev->xselection.requestor, ev->xselection.selection);
		}
	} else {
		return;
	}
	
	oldlen = strlen(selection_str);
	strncpy(before, selection_str, CHKSZ);

	selection_str[0] = '\0';
	slen = 0;

	/* read in the current value of PRIMARY or CLIPBOARD: */
	do {
		if (XGetWindowProperty(dpy, ev->xselection.requestor,
		    ev->xselection.property, nitems/4, PROP_MAX/16, True,
		    AnyPropertyType, &type, &format, &nitems, &bytes_after,
		    &data) == Success) {

			dlen = nitems * (format/8);
			if (slen + dlen > PROP_MAX) {
				/* too big */
				toobig = 1;
				XFree_wr(data);
				if (err) {	/* cut down on messages */
					break;
				} else {
					err = 5;
				}
				rfbLog("warning: truncating large PRIMARY"
				    "/CLIPBOARD selection > %d bytes.\n",
				    PROP_MAX);
				break;
			}
if (debug_sel) fprintf(stderr, "selection_send: data: '%s' dlen: %d nitems: %lu ba: %lu\n", data, dlen, nitems, bytes_after);
			memcpy(selection_str+slen, data, dlen);
			slen += dlen;
			selection_str[slen] = '\0';
			XFree_wr(data);
		}
	} while (bytes_after > 0);

	if (! toobig) {
		err = 0;
	} else if (err) {
		err--;
	}

	if (! sent_one) {
		/* try to force a send first time in */
		oldlen = -1;
		sent_one = 1;
	}
	if (debug_sel) {
		rfbLog("selection_send:  %s '%s'\n",
		    ev->xselection.selection == XA_PRIMARY ? "PRIMARY  " : "CLIPBOARD",
		    selection_str);
	}

	/* look for changes in the new value */
	newlen = strlen(selection_str);
	strncpy(after, selection_str, CHKSZ);

	if (oldlen == newlen && strncmp(before, after, CHKSZ) == 0) {
		/* evidently no change */
		if (debug_sel) {
			rfbLog("selection_send:  no change.\n");
		}
		return;
	}
	if (newlen == 0) {
		/* do not bother sending a null string out */
		return;
	}

	if (! all_clients_initialized()) {
		rfbLog("selection_send: no send: uninitialized clients\n");
		return; /* some clients initializing, cannot send */ 
	}

	if (unixpw_in_progress) {
		return;
	}

	/* now send it to any connected VNC clients (rfbServerCutText) */
	if (!screen) {
		return;
	}

	len = newlen;
	if (ev->xselection.selection == XA_PRIMARY) {
		primary_len = len;
	} else if (clipboard_atom && ev->xselection.selection == clipboard_atom)  {
		clipboard_len = len;
	}
	if (check_sel_direction("send", "selection_send", selection_str, len)) {
		rfbSendServerCutText(screen, selection_str, len);
	}
#endif	/* NO_X11 */
}

void resend_selection(char *type) {
#if NO_X11
	RAWFB_RET_VOID
	if (!type) {}
	return;
#else
	char *selection_str = "";
	int len = 0;

	RAWFB_RET_VOID

	if (! all_clients_initialized()) {
		rfbLog("selection_send: no send: uninitialized clients\n");
		return; /* some clients initializing, cannot send */ 
	}
	if (unixpw_in_progress) {
		return;
	}
	if (!screen) {
		return;
	}

	if (!strcmp(type, "cutbuffer")) {
		selection_str = cutbuffer_str;
		len = cutbuffer_len;
	} else if (!strcmp(type, "clipboard")) {
		selection_str = clipboard_str;
		len = clipboard_len;
	} else if (!strcmp(type, "primary")) {
		selection_str = primary_str;
		len = primary_len;
	}
	if (check_sel_direction("send", "selection_send", selection_str, len)) {
		rfbSendServerCutText(screen, selection_str, len);
	}
#endif	/* NO_X11 */
}