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

["Denis V. Lunev" <den@openvz.org>]

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"
 #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 */ }
+    },
+};
 
 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);
-- 
2.5.0