[Qemu-devel] [PULL 32/36] qmp: add command "x-oob-test"

[Eric Blake <eblake@redhat.com>]

From: Peter Xu <peterx@redhat.com>

This command is only used to test OOB functionality.  It should not be
used for any other purposes.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180309090006.10018-22-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qapi/misc.json | 18 ++++++++++++++++++
 qmp.c          | 16 ++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/qapi/misc.json b/qapi/misc.json
index b6ebf210ba8..fc3550f3acc 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -3279,3 +3279,21 @@
 ##
 { 'event': 'COMMAND_DROPPED' ,
   'data': { 'id': 'any', 'reason': 'CommandDropReason' } }
+
+##
+# @x-oob-test:
+#
+# Test OOB functionality.  When sending this command with lock=true,
+# it'll try to hang the dispatcher.  When sending it with lock=false,
+# it'll try to notify the locked thread to continue.  Note: it should
+# only be used by QMP test program rather than anything else.
+#
+# Since: 2.12
+#
+# Example:
+#
+# { "execute": "x-oob-test",
+#   "arguments": { "lock": true } }
+##
+{ 'command': 'x-oob-test', 'data' : { 'lock': 'bool' },
+  'allow-oob': true }
diff --git a/qmp.c b/qmp.c
index 7e606d84867..ea3760acb12 100644
--- a/qmp.c
+++ b/qmp.c
@@ -770,3 +770,19 @@ MemoryInfo *qmp_query_memory_size_summary(Error **errp)

     return mem_info;
 }
+
+static QemuSemaphore x_oob_test_sem;
+
+static void __attribute__((constructor)) x_oob_test_init(void)
+{
+    qemu_sem_init(&x_oob_test_sem, 0);
+}
+
+void qmp_x_oob_test(bool lock, Error **errp)
+{
+    if (lock) {
+        qemu_sem_wait(&x_oob_test_sem);
+    } else {
+        qemu_sem_post(&x_oob_test_sem);
+    }
+}
-- 
2.14.3