[rdesktop-devel] Valgrind errors

[Peter A. <pe...@ce...>]

When running rdesktop through valgrind, I get:

==22630== Syscall param writev(vector[...]) contains uninitialised or 
unaddressable byte(s)
==22630==    at 0x69A87C: writev (in /lib/tls/libc-2.3.3.so)
==22630==    by 0x7951AF: (within /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x795F2E: _X11TransWritev (in 
/usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x7765F4: _XSend (in /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x76BB53: (within /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x76C26A: XPutImage (in /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x80508A3: ui_desktop_restore (xwin.c:2181)
==22630==    by 0x805744D: process_desksave (orders.c:357)
==22630==    by 0x8058301: process_orders (orders.c:1013)
==22630==  Address 0x1B9C40AA is 834 bytes inside a block of size 241604 
alloc'd
==22630==    at 0x1B904A80: malloc (vg_replace_malloc.c:131)
==22630==    by 0x778BB4: _XAllocScratch (in /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x76BC81: (within /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x76C26A: XPutImage (in /usr/X11R6/lib/libX11.so.6.2)
==22630==    by 0x80508A3: ui_desktop_restore (xwin.c:2181)
==22630==    by 0x805744D: process_desksave (orders.c:357)
==22630==    by 0x8058301: process_orders (orders.c:1013)
==22630==    by 0x805BE34: rdp5_process (rdp5.c:91)
==22630==    by 0x80555EA: rdp_recv (rdp.c:70)

The problem seems to be something with the combo:

XCreateImage/XPutImage. I've tried changing:

image = XCreateImage(g_display, g_visual, g_depth, ZPixmap, 0,
		    (char *) data, cx, cy, BitmapPad(g_display), 
                    cx * g_bpp / 8);

into:

image = XCreateImage(g_display, g_visual, g_depth, ZPixmap, 0,
                    (char *) data, cx, cy, BitmapPad(g_display),
                    0);

This makes the warnings disappear, but instead, another one pops up:

==23332== Syscall param writev(vector[...]) contains uninitialised or unaddressable byte(s)
==23332==    at 0x69A87C: writev (in /lib/tls/libc-2.3.3.so)
==23332==    by 0x7951AF: (within /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x795F2E: _X11TransWritev (in /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x7765F4: _XSend (in /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x76BB53: (within /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x76C26A: XPutImage (in /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x804EDAA: ui_paint_bitmap (xwin.c:1523)
==23332==    by 0x805681A: process_bitmap_updates (rdp.c:986)
==23332==    by 0x805BE4C: rdp5_process (rdp5.c:95)
==23332==  Address 0x1BA88FDA is 226 bytes inside a block of size 8436 alloc'd
==23332==    at 0x1B904A80: malloc (vg_replace_malloc.c:131)
==23332==    by 0x778BB4: _XAllocScratch (in /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x76BC81: (within /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x76C26A: XPutImage (in /usr/X11R6/lib/libX11.so.6.2)
==23332==    by 0x804EDAA: ui_paint_bitmap (xwin.c:1523)
==23332==    by 0x805681A: process_bitmap_updates (rdp.c:986)
==23332==    by 0x805BE4C: rdp5_process (rdp5.c:95)
==23332==    by 0x80555D2: rdp_recv (rdp.c:70)
==23332==    by 0x8056B50: rdp_loop (rdp.c:1171)

I must admit that I know very little about X11 image padding. For example, 
when is it appropriate to use the BitmapPad function, and when should this 
custom code be used?:

	int bitmap_pad;

	if (g_server_bpp == 8)
	{
		bitmap_pad = 8;
	}
	else
	{
		bitmap_pad = g_bpp;

		if (g_bpp == 24)
			bitmap_pad = 32;
	}

Any ideas?

-- 
Peter Åstrand		Chief Developer
Cendio			www.thinlinc.com
Teknikringen 3		www.cendio.se
583 30 Linköping        Phone: +46-13-21 46 00