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Date: Wed, 4 Aug 2010 10:53:10 +0100
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Subject: Re: [Qemu-devel] [Tracing][PATCH] Add options to specify trace file
	name at startup and runtime.
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: Prerna Saxena <prerna@linux.vnet.ibm.com>
Cc: Ananth Narayan <ananth@linux.vnet.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

On Wed, Aug 4, 2010 at 10:33 AM, Prerna Saxena
<prerna@linux.vnet.ibm.com> wrote:
> On 08/03/2010 07:45 PM, Stefan Hajnoczi wrote:
>> On Tue, Aug 3, 2010 at 6:37 AM, Prerna Saxena<prerna@linux.vnet.ibm.com>
>> =A0wrote:
>>> @@ -2590,6 +2597,12 @@ int main(int argc, char **argv, char **envp)
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 }
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 xen_mode =3D XEN_ATTACH;
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 break;
>>> +#ifdef CONFIG_SIMPLE_TRACE
>>> + =A0 =A0 =A0 =A0 =A0 =A0case QEMU_OPTION_trace:
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0trace_file =3D (char *) qemu_malloc(st=
rlen(optarg) + 1);
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0strcpy(trace_file, optarg);
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0break;
>>> +#endif
>>
>> Malloc isn't necessary, just hold the optarg pointer like gdbstub_dev
>> and other string options do.
>
> It wouldnt be corect to use optarg directly here. If this optional argume=
nt
> is not specified, st_set_file_name() is called with a NULL argument, and =
the
> filename defaults to config-specified name.
> (This is how gdbstub_dev works too. The optional argument is copied to
> gdbstub_dev if provided.)

const char *trace_file =3D NULL;
...
switch (...) {
    case QEMU_OPTION_trace:
        trace_file =3D optarg;
        break;
}
...
st_set_trace_file(trace_file);

There is no need to malloc/strcpy/free.

Stefan