[Libvir] Re: [PATCH 2/7] Fix issues with QEMU monitor interface.

On Sun, Aug 12, 2007 at 07:11:34PM -0400, Jim Paris wrote: > Due to the TTY layer, sending "\n" to the qemu monitor translates > into "\r\n" when received. This triggers a bug in older versions of > QEMU (KVM <= 33) because the same command is executed twice, and > still has problems with fixed QEMU because the "(qemu)" prompt is > printed twice. Switch all monitor commands to end with "\r" which > avoids both issues. > > The QEMU monitor sends frequent terminal escape sequences, typically > \033[D and \033[K. At times, these interfere with the prompt > detection when they get sent between "\n" and "(qemu) ". Fix the > issue by filtering out these sequences when they are received. I think DanP can better comment on the QEmu interaction than me, but the patch looks simple and clean except:

> @@ -1333,14 +1335,23 @@ static int qemudMonitorCommand(struct qemud_driver *driver ATTRIBUTE_UNUSED, > return -1; > } > buf = b; > - memmove(buf+size, data, got); > - buf[size+got] = '\0'; > - size += got; > + > + /* Copy data, skipping 3-byte escape sequences */ > + for (i = 0; i < got; i++) { > + if (data[i] == '\033') > + skip = 3; > + if (skip) > + skip--; > + else > + buf[size++] = data[i]; > + } > + buf[size] = '\0'; > } It seems that if for some reason you do a partial read on the QEmu console descriptor ending in the middle of the escape command you may have a problem. But it's possible that the way reads are done, and input is chunked garantees that this won't happen, DanP can probably confirm it's just fine :-)