[Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Programmingkid]

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Print the ID of each device when 'info usb' is used in the monitor.

Signed-off-by: John Arbuckle <programmingkidx@gmail.com>

---
This patch is easier to test when the qdev-monitor.c patch I
also submitted is applied first. It can still be tested without
it. Just run QEMU with the -usb option. Then go to the monitor
and type "device_add usb-mouse,id=mouse-one". You will see the
ID printed with the usb-mouse's info when you type 'info usb'.

The ID is used by device_del to remove a device from QEMU. With
this patch, the user can actually see the ID of the usb device
making it possible to actually pick the right device to remove. 

 hw/usb/bus.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 5f39e1e..d2a726c 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -655,9 +655,11 @@ void hmp_info_usb(Monitor *mon, const QDict *qdict)
             dev = port->dev;
             if (!dev)
                 continue;
-            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s Mb/s, Product %s\n",
-                           bus->busnr, dev->addr, port->path, usb_speed(dev->speed),
-                           dev->product_desc);
+            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s Mb/s,"
+                                "Product %s, ID %s\n",
+                           bus->busnr, dev->addr, port->path,
+                           usb_speed(dev->speed),
+                           dev->product_desc, dev->qdev.id);
         }
     }
 }
-- 
1.7.5.4


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Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Gerd Hoffmann]

On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
> Mb/s,"
> +                                "Product %s, ID %s\n",
> +                           bus->busnr, dev->addr, port->path,
> +                           usb_speed(dev->speed),
> +                           dev->product_desc, dev->qdev.id);
> 

dev->qdev.id can be NULL.

cheers,
  Gerd

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Programmingkid]

On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:

> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
>> Mb/s,"
>> +                                "Product %s, ID %s\n",
>> +                           bus->busnr, dev->addr, port->path,
>> +                           usb_speed(dev->speed),
>> +                           dev->product_desc, dev->qdev.id);
>> 
> 
> dev->qdev.id can be NULL.
> 
> cheers,
>  Gerd

That isn't a problem. It will just say "null" when it is printed. No crash or garbage text.

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Daniel P. Berrange]

On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
> 
> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
> 
> > On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
> >> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
> >> Mb/s,"
> >> +                                "Product %s, ID %s\n",
> >> +                           bus->busnr, dev->addr, port->path,
> >> +                           usb_speed(dev->speed),
> >> +                           dev->product_desc, dev->qdev.id);
> >> 
> > 
> > dev->qdev.id can be NULL.
> > 
> > cheers,
> >  Gerd
> 
> That isn't a problem. It will just say "null" when it is printed.
> No crash or garbage text.

Handling of '%s' with NULL is undefined by the standard. Linux
glibc prints the string "null", but other implementations can
crash.

Regards,
Daniel
-- 
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Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Programmingkid]

On Aug 28, 2015, at 9:35 AM, Daniel P. Berrange wrote:

> On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
>> 
>> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
>> 
>>> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
>>>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
>>>> Mb/s,"
>>>> +                                "Product %s, ID %s\n",
>>>> +                           bus->busnr, dev->addr, port->path,
>>>> +                           usb_speed(dev->speed),
>>>> +                           dev->product_desc, dev->qdev.id);
>>>> 
>>> 
>>> dev->qdev.id can be NULL.
>>> 
>>> cheers,
>>> Gerd
>> 
>> That isn't a problem. It will just say "null" when it is printed.
>> No crash or garbage text.
> 
> Handling of '%s' with NULL is undefined by the standard. Linux
> glibc prints the string "null", but other implementations can
> crash.

"null" is also printed on Mac OS X. 

Do you want dev->qdev.id replaced with this? (dev->qdev.id != NULL) ? dev->qdev.id : "null"

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Daniel P. Berrange]

On Fri, Aug 28, 2015 at 09:39:43AM -0400, Programmingkid wrote:
> 
> On Aug 28, 2015, at 9:35 AM, Daniel P. Berrange wrote:
> 
> > On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
> >> 
> >> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
> >> 
> >>> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
> >>>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
> >>>> Mb/s,"
> >>>> +                                "Product %s, ID %s\n",
> >>>> +                           bus->busnr, dev->addr, port->path,
> >>>> +                           usb_speed(dev->speed),
> >>>> +                           dev->product_desc, dev->qdev.id);
> >>>> 
> >>> 
> >>> dev->qdev.id can be NULL.
> >>> 
> >>> cheers,
> >>> Gerd
> >> 
> >> That isn't a problem. It will just say "null" when it is printed.
> >> No crash or garbage text.
> > 
> > Handling of '%s' with NULL is undefined by the standard. Linux
> > glibc prints the string "null", but other implementations can
> > crash.
> 
> "null" is also printed on Mac OS X.

I don't know if it is still true in latest versions, but historically
Solaris would crash on NULL.

  "The problem is that while you can printf("%s",NULL); in most
   Linux distributions, doing the same in Solaris caused the
   executable to exit and generate a core."

  https://blogs.oracle.com/bnitz/entry/asc_and_sprintf_s_null

> Do you want dev->qdev.id replaced with this? (dev->qdev.id != NULL) ? dev->qdev.id : "null"

It can be a bit shorter if you just leave out the "!= NULL" bit and
rely on implicit conversion of non-null to a boolean true. I'm not
sure if QEMU has a macro wrapper for hiding this possibly.


Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
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Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Gerd Hoffmann]

On Fr, 2015-08-28 at 09:39 -0400, Programmingkid wrote:
> On Aug 28, 2015, at 9:35 AM, Daniel P. Berrange wrote:
> 
> > On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
> >> 
> >> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
> >> 
> >>> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
> >>>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
> >>>> Mb/s,"
> >>>> +                                "Product %s, ID %s\n",
> >>>> +                           bus->busnr, dev->addr, port->path,
> >>>> +                           usb_speed(dev->speed),
> >>>> +                           dev->product_desc, dev->qdev.id);
> >>>> 
> >>> 
> >>> dev->qdev.id can be NULL.
> >>> 
> >>> cheers,
> >>> Gerd
> >> 
> >> That isn't a problem. It will just say "null" when it is printed.
> >> No crash or garbage text.
> > 
> > Handling of '%s' with NULL is undefined by the standard. Linux
> > glibc prints the string "null", but other implementations can
> > crash.
> 
> "null" is also printed on Mac OS X. 
> 
> Do you want dev->qdev.id replaced with this? (dev->qdev.id != NULL) ? dev->qdev.id : "null"

Even better: Don't print "ID: ..." in the first place in case it is not
present.

cheers,
  Gerd

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Programmingkid]

On Aug 28, 2015, at 9:50 AM, Gerd Hoffmann wrote:

> On Fr, 2015-08-28 at 09:39 -0400, Programmingkid wrote:
>> On Aug 28, 2015, at 9:35 AM, Daniel P. Berrange wrote:
>> 
>>> On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
>>>> 
>>>> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
>>>> 
>>>>> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
>>>>>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
>>>>>> Mb/s,"
>>>>>> +                                "Product %s, ID %s\n",
>>>>>> +                           bus->busnr, dev->addr, port->path,
>>>>>> +                           usb_speed(dev->speed),
>>>>>> +                           dev->product_desc, dev->qdev.id);
>>>>>> 
>>>>> 
>>>>> dev->qdev.id can be NULL.
>>>>> 
>>>>> cheers,
>>>>> Gerd
>>>> 
>>>> That isn't a problem. It will just say "null" when it is printed.
>>>> No crash or garbage text.
>>> 
>>> Handling of '%s' with NULL is undefined by the standard. Linux
>>> glibc prints the string "null", but other implementations can
>>> crash.
>> 
>> "null" is also printed on Mac OS X. 
>> 
>> Do you want dev->qdev.id replaced with this? (dev->qdev.id != NULL) ? dev->qdev.id : "null"
> 
> Even better: Don't print "ID: ..." in the first place in case it is not
> present.

The ID is printed so if the user needs to remove the device, device_del <id> can be used. 

If the ID isn't printed here, where do you want it to be printed? "info device-id"?

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Peter Maydell]

On 28 August 2015 at 14:55, Programmingkid <programmingkidx@gmail.com> wrote:
> On Aug 28, 2015, at 9:50 AM, Gerd Hoffmann wrote:
>> Even better: Don't print "ID: ..." in the first place in case it is not
>> present.
>
> The ID is printed so if the user needs to remove the device, device_del <id> can be used.
>
> If the ID isn't printed here, where do you want it to be printed? "info device-id"?

Gerd means, "print nothing at all, rather than ', ID null'".
There's no point in printing something which isn't actually
an ID you can use to delete the device.

thanks
-- PMM

Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info usb' used

[Programmingkid]

On Aug 28, 2015, at 12:07 PM, Peter Maydell wrote:

> On 28 August 2015 at 14:55, Programmingkid <programmingkidx@gmail.com> wrote:
>> On Aug 28, 2015, at 9:50 AM, Gerd Hoffmann wrote:
>>> Even better: Don't print "ID: ..." in the first place in case it is not
>>> present.
>> 
>> The ID is printed so if the user needs to remove the device, device_del <id> can be used.
>> 
>> If the ID isn't printed here, where do you want it to be printed? "info device-id"?
> 
> Gerd means, "print nothing at all, rather than ', ID null'".
> There's no point in printing something which isn't actually
> an ID you can use to delete the device.

Ok. I can make a patch that does that.