Control: clone -1 -2
Control: reassign -1 squeak-vm
Control: reassign -2 squeak-plugins-scratch
On Sun, Aug 05, 2018 at 07:33:58PM +0200, Bernhard Übelacker wrote:
> Hello Wouter,
> thanks for this additional information.
>
> I could reproduce the issue with a usb webcam inside a buster amd64 VM.
> Unfortunately this camera button was with the german translation not
> visible with the small resolution of that VM.
>
> It took a little time to get into the smalltalk side of things.
> But I think I have found a problem - on the c side of the plugins.
>
>
>
> (gdb) bt
> #0 0x00007fffafa33c82 in convertImageRGB24toARGB32 (cam=0x7fffafa37180
> <camInfo>) at ./unix/plugins/CameraPlugin/sqCamera-linux.c:333
> #1 0x00007fffafa33f2a in convertImage (cam=0x7fffafa37180 <camInfo>) at
> ./unix/plugins/CameraPlugin/sqCamera-linux.c:412
> #2 0x00007fffafa34d10 in CameraGetFrame (camNum=1, buf=0x7fffb2b9fcb4 "",
> pixelCount=76800) at ./unix/plugins/CameraPlugin/sqCamera-linux.c:836
> #3 0x00007fffafa3352c in primGetFrame () at
> ./unix/src/plugins/CameraPlugin/CameraPlugin.c:160
> #4 0x0000555555578ca4 in dispatchFunctionPointer
> (aFunctionPointer=0x7fffafa33461 <primGetFrame>) at
> ./build-tree/gnu-interp.c:3809
> #5 0x00005555555769f8 in callExternalPrimitive (functionID=0x7fffafa33461
> <primGetFrame>) at ./build-tree/gnu-interp.c:2512
> #6 0x000055555558fc92 in primitiveExternalCall () at
> ./build-tree/gnu-interp.c:17732
> #7 0x0000555555578ca4 in dispatchFunctionPointer
> (aFunctionPointer=0x55555558faf0 <primitiveExternalCall>) at
> ./build-tree/gnu-interp.c:3809
> #8 0x000055555558227a in interpret () at ./build-tree/gnu-interp.c:9339
> #9 0x00005555555a7cef in main (argc=8, argv=0x7fffffffe2a8,
> envp=0x7fffffffe2f0) at ./unix/vm/sqUnixMain.c:1458
>
> (gdb) list convertImageRGB24toARGB32
> 319 static void
> 320 convertImageRGB24toARGB32 (camPtr cam)
> 321 {
> 322 unsigned char *src = cam->inBuffer;
> 323 unsigned long int *dst = cam->sqBuffer; <--
> sizeof(*dst) == 8, should be 4 ?
> 324 unsigned long int pixelCount = cam->sqPixels;
> 325 unsigned long int pixel;
> 326 int i;
> 327
> 328 if (0 == dst) return;
> 329
> 330 for ( i = 0; i < pixelCount; i++) {
> 331 pixel = 0xFF000000 | (*src++ << 16);
> 332 pixel = pixel | (*src++ << 8);
> 333 *dst++ = pixel | *src++;
> 334 }
> 335 }
>
>
>
> Here the buffer allocated in the squeak-vm is given to primGetFrame
> and gets finally the image written to in convertImageRGB24toARGB32.
> Unfortunately these conversion functions use "unsigned long int *dst",
> with a long int having a size of 8 bytes at amd64, while we got
> just 4 bytes per pixel reserved from squeak-vm, therefore
> overrunning our reserved buffer.
>
>
> When just installing the packages the plugin so.CameraPlugin gets
> used from the package squeak-plugins-scratch.
> But a similar so.CameraPlugin is already packaged with squeak-vm.
>
> squeak-vm: /usr/lib/squeak/4.10.2.2614/so.CameraPlugin
> squeak-plugins-scratch: /usr/lib/scratch/plugins/so.CameraPlugin
>
> So this probably should be clarified if the plugins are really
> needed in both packages.
>
>
> Therefore this report should be changed to packages
> squeak-vm and squeak-plugins-scratch?
Thanks for you work, I am doing this now.
> Attached both patches change this buffer element size in the conversion
> function from 8 to 4. With them applied both plugins were able to
> show me the picture from the webcam inside scratch.
>
>
> Kind regards,
> Bernhard
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
