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Re: [libvirt] [PATCH] Make QEMU text monitor parsing more robust



On Tue, Dec 08, 2009 at 06:08:04PM +0000, Daniel P. Berrange wrote:
> The QEMU 0.10.0 release (and possibly other 0.10.x) has a bug where
> it sometimes/often forgets to display the initial monitor greeting
> line, soley printing a (qemu).  This in turn confuses the text
> console parsing because it has a '(qemu)' it is not expecting. The
> confusion results in a negative malloc. Bad things follow.
> 
> This re-writes the text console handling to be more robust. The key
> idea is that it should only look for a (qemu), once it has seen the
> original command echo'd back. This ensures it'll skip the bogus stray
> (qemu) with broken QEMUs.
> 
> * src/qemu/qemu_monitor.c: Add some (disabled) debug code
> * src/qemu/qemu_monitor_text.c: Re-write way command replies
>   are detected
> ---
>  src/qemu/qemu_monitor.c      |   28 +++++++++++
>  src/qemu/qemu_monitor_text.c |  102 +++++++++++++++++++++++++++--------------
>  2 files changed, 95 insertions(+), 35 deletions(-)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index abb763c..103cf28 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -39,6 +39,8 @@
>  
>  #define VIR_FROM_THIS VIR_FROM_QEMU
>  
> +#define QEMU_DEBUG_RAW_IO 0
> +
>  struct _qemuMonitor {
>      virMutex lock;
>      virCond notify;
> @@ -163,6 +165,24 @@ char *qemuMonitorEscapeShell(const char *in)
>  }
>  
>  
> +#if QEMU_DEBUG_RAW_IO
> +#include <c-ctype.h>
> +static char * qemuMonitorEscapeNonPrintable(const char *text)
> +{
> +    int i;
> +    virBuffer buf = VIR_BUFFER_INITIALIZER;
> +    for (i = 0 ; text[i] != '\0' ; i++) {
> +        if (c_isprint(text[i]) ||

Hum I just hope c_isprint behaviour doesn't depend on the user locale,
otherwise I would just replace it with an explicit value test on the
ASCII range, not a big deal since it's just for debug though ...

> +            text[i] == '\n' ||
> +            (text[i] == '\r' && text[i+1] == '\n'))
> +            virBufferVSprintf(&buf,"%c", text[i]);
> +        else
> +            virBufferVSprintf(&buf, "0x%02x", text[i]);
> +    }
> +    return virBufferContentAndReset(&buf);
> +}
> +#endif

  ACK,

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/


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