Re: [Qemu-devel] [PATCH 1/6] qemu-io: enable tracing in qemu-io

[Paolo Bonzini <pbonzini@redhat.com>]

On 14/05/2016 14:01, Denis V. Lunev wrote:
> It would be convinient to enable tracepoints in qemu-io binary. This would
> allow to perform investigations without additional code recompilations.
> 
> The command line will be exactly the same as in qemu-system.
> 
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  qemu-io.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
> 
> diff --git a/qemu-io.c b/qemu-io.c
> index 5ef3ef7..2d0d2b0 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -18,6 +18,7 @@
>  #include "qemu/option.h"
>  #include "qemu/config-file.h"
>  #include "qemu/readline.h"
> +#include "qemu/log.h"

Why does this need qemu/log.h, as opposed to trace/control.h (which
probably should be moved to include/qemu/trace.h, but that's a patch for
another day)?

>  #include "qapi/qmp/qstring.h"
>  #include "qom/object_interfaces.h"
>  #include "sysemu/block-backend.h"
> @@ -419,6 +420,25 @@ static QemuOptsList qemu_object_opts = {
>      },
>  };
>  
> +static QemuOptsList qemu_trace_opts = {
> +    .name = "trace",
> +    .implied_opt_name = "enable",
> +    .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
> +    .desc = {
> +        {
> +            .name = "enable",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "events",
> +            .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "file",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        { /* end of list */ }
> +    },
> +};

Stefan, should this be in trace/control.c instead, so that vl.c and
qemu-io.c can share it?

Otherwise looks sane.

Thanks,

Paolo

>  static QemuOptsList file_opts = {
>      .name = "file",
> @@ -473,6 +493,7 @@ int main(int argc, char **argv)
>  
>      module_call_init(MODULE_INIT_QOM);
>      qemu_add_opts(&qemu_object_opts);
> +    qemu_add_opts(&qemu_trace_opts);
>      bdrv_init();
>  
>      while ((c = getopt_long(argc, argv, sopt, lopt, &opt_index)) != -1) {
> @@ -512,10 +533,32 @@ int main(int argc, char **argv)
>              }
>              break;
>          case 'T':
> +        {
> +            QemuOpts *trace_opts;
> +            char *trace_file;
> +
> +            trace_opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
> +                                                 optarg, true);
> +            if (trace_opts == NULL) {
> +                exit(1);
> +            }
> +            if (qemu_opt_get(trace_opts, "enable")) {
> +                trace_enable_events(qemu_opt_get(trace_opts, "enable"));
> +            }
> +            trace_init_events(qemu_opt_get(trace_opts, "events"));
> +
> +            trace_file = g_strdup(qemu_opt_get(trace_opts, "file"));
> +            qemu_opts_del(trace_opts);
> +
>              if (!trace_init_backends()) {
>                  exit(1); /* error message will have been printed */
>              }
> +            trace_init_file(trace_file);
> +            g_free(trace_file);
> +
> +            qemu_set_log(LOG_TRACE);
>              break;
> +        }
>          case 'V':
>              printf("%s version %s\n", progname, QEMU_VERSION);
>              exit(0);
>