qemu: Issue query-iothreads and to get list of active IOThreads

Generate infrastructure and test to handle fetching the QMP
IOThreads data.

src/qemu/qemu_monitor.c

@@ -4061,3 +4061,44 @@ qemuMonitorRTCResetReinjection(qemuMonitorPtr mon)
 
     return qemuMonitorJSONRTCResetReinjection(mon);
 }
+
+/**
+ * qemuMonitorGetIOThreads:
+ * @mon: Pointer to the monitor
+ * @iothreads: Location to return array of IOThreadInfo data
+ *
+ * Issue query-iothreads command.
+ * Retrieve the list of iothreads defined/running for the machine
+ *
+ * Returns count of IOThreadInfo structures on success
+ *        -1 on error.
+ */
+int
+qemuMonitorGetIOThreads(qemuMonitorPtr mon,
+                        qemuMonitorIOThreadsInfoPtr **iothreads)
+{
+
+    VIR_DEBUG("mon=%p iothreads=%p", mon, iothreads);
+
+    if (!mon) {
+        virReportError(VIR_ERR_INVALID_ARG, "%s",
+                       _("monitor must not be NULL"));
+        return -1;
+    }
+
+    if (!mon->json) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("JSON monitor is required"));
+        return -1;
+    }
+
+    return qemuMonitorJSONGetIOThreads(mon, iothreads);
+}
+
+void qemuMonitorIOThreadsInfoFree(qemuMonitorIOThreadsInfoPtr iothread)
+{
+    if (!iothread)
+        return;
+    VIR_FREE(iothread->name);
+    VIR_FREE(iothread);
+}

src/qemu/qemu_monitor.h

@@ -798,6 +798,18 @@ int qemuMonitorGetGuestCPU(qemuMonitorPtr mon,
 
 int qemuMonitorRTCResetReinjection(qemuMonitorPtr mon);
 
+typedef struct _qemuMonitorIOThreadsInfo qemuMonitorIOThreadsInfo;
+typedef qemuMonitorIOThreadsInfo *qemuMonitorIOThreadsInfoPtr;
+
+struct _qemuMonitorIOThreadsInfo {
+    char *name;
+    int thread_id;
+};
+int qemuMonitorGetIOThreads(qemuMonitorPtr mon,
+                            qemuMonitorIOThreadsInfoPtr **iothreads);
+
+void qemuMonitorIOThreadsInfoFree(qemuMonitorIOThreadsInfoPtr iothread);
+
 /**
  * When running two dd process and using <> redirection, we need a
  * shell that will not truncate files.  These two strings serve that

src/qemu/qemu_monitor_json.c

@@ -5910,3 +5910,94 @@ qemuMonitorJSONRTCResetReinjection(qemuMonitorPtr mon)
     virJSONValueFree(reply);
     return ret;
 }
+
+/**
+ * Query and parse returned array of data such as:
+ *
+ *  {u'return': [{u'id': u'iothread1', u'thread-id': 30992}, \
+ *               {u'id': u'iothread2', u'thread-id': 30993}]}
+ */
+int
+qemuMonitorJSONGetIOThreads(qemuMonitorPtr mon,
+                            qemuMonitorIOThreadsInfoPtr **iothreads)
+{
+    int ret = -1;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+    virJSONValuePtr data;
+    qemuMonitorIOThreadsInfoPtr *infolist = NULL;
+    int n = 0;
+    size_t i;
+
+    *iothreads = NULL;
+
+    if (!(cmd = qemuMonitorJSONMakeCommand("query-iothreads", NULL)))
+        return ret;
+
+    ret = qemuMonitorJSONCommand(mon, cmd, &reply);
+
+    if (ret == 0)
+        ret = qemuMonitorJSONCheckError(cmd, reply);
+
+    if (ret < 0)
+        goto cleanup;
+
+    ret = -1;
+
+    if (!(data = virJSONValueObjectGet(reply, "return"))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-iothreads reply was missing return data"));
+        goto cleanup;
+    }
+
+    if ((n = virJSONValueArraySize(data)) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-iothreads reply data was not an array"));
+        goto cleanup;
+    }
+
+    /* null-terminated list */
+    if (VIR_ALLOC_N(infolist, n + 1) < 0)
+        goto cleanup;
+
+    for (i = 0; i < n; i++) {
+        virJSONValuePtr child = virJSONValueArrayGet(data, i);
+        const char *tmp;
+        qemuMonitorIOThreadsInfoPtr info;
+
+        if (VIR_ALLOC(info) < 0)
+            goto cleanup;
+
+        infolist[i] = info;
+
+        if (!(tmp = virJSONValueObjectGetString(child, "id"))) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("query-iothreads reply data was missing 'id'"));
+            goto cleanup;
+        }
+
+        if (VIR_STRDUP(info->name, tmp) < 0)
+            goto cleanup;
+
+        if (virJSONValueObjectGetNumberInt(child, "thread-id",
+                                           &info->thread_id) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("query-iothreads reply has malformed "
+                             "'thread-id' data"));
+            goto cleanup;
+        }
+    }
+
+    ret = n;
+    *iothreads = infolist;
+
+ cleanup:
+    if (ret < 0 && infolist) {
+        for (i = 0; i < n; i++)
+            qemuMonitorIOThreadsInfoFree(infolist[i]);
+        VIR_FREE(infolist);
+    }
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}

src/qemu/qemu_monitor_json.h

@@ -446,4 +446,8 @@ int qemuMonitorJSONGetGuestCPU(qemuMonitorPtr mon,
                                virCPUDataPtr *data);
 
 int qemuMonitorJSONRTCResetReinjection(qemuMonitorPtr mon);
+
+int qemuMonitorJSONGetIOThreads(qemuMonitorPtr mon,
+                                qemuMonitorIOThreadsInfoPtr **iothreads)
+    ATTRIBUTE_NONNULL(2);
 #endif /* QEMU_MONITOR_JSON_H */

tests/qemumonitorjsontest.c

@@ -2216,6 +2216,76 @@ testQemuMonitorJSONGetNonExistingCPUData(const void *opaque)
     return ret;
 }
 
+static int
+testQemuMonitorJSONGetIOThreads(const void *data)
+{
+    virDomainXMLOptionPtr xmlopt = (virDomainXMLOptionPtr)data;
+    qemuMonitorTestPtr test = qemuMonitorTestNewSimple(true, xmlopt);
+    qemuMonitorIOThreadsInfoPtr *info;
+    int ninfo = 0;
+    int ret = -1;
+    size_t i;
+
+    if (!test)
+        return -1;
+
+    if (qemuMonitorTestAddItem(test, "query-iothreads",
+                               "{ "
+                               "  \"return\": [ "
+                               "   { "
+                               "     \"id\": \"iothread1\", "
+                               "     \"thread-id\": 30992 "
+                               "   }, "
+                               "   { "
+                               "     \"id\": \"iothread2\", "
+                               "     \"thread-id\": 30993 "
+                               "   } "
+                               "  ]"
+                               "}") < 0)
+        goto cleanup;
+
+    if ((ninfo = qemuMonitorGetIOThreads(qemuMonitorTestGetMonitor(test),
+                                         &info)) < 0)
+        goto cleanup;
+
+    if (ninfo != 2) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       "ninfo %d is not 2", ninfo);
+        goto cleanup;
+    }
+
+#define CHECK(i, wantname, wantthread_id)                               \
+    do {                                                                \
+        if (STRNEQ(info[i]->name, (wantname))) {                        \
+            virReportError(VIR_ERR_INTERNAL_ERROR,                      \
+                           "name %s is not %s",                         \
+                           info[i]->name, (wantname));                  \
+            goto cleanup;                                               \
+        }                                                               \
+        if (info[i]->thread_id != (wantthread_id)) {                    \
+            virReportError(VIR_ERR_INTERNAL_ERROR,                      \
+                           "thread_id %d is not %d",                    \
+                           info[i]->thread_id, (wantthread_id));        \
+            goto cleanup;                                               \
+        }                                                               \
+    } while (0)
+
+    CHECK(0, "iothread1", 30992);
+    CHECK(1, "iothread2", 30993);
+
+#undef CHECK
+
+    ret = 0;
+
+ cleanup:
+    qemuMonitorTestFree(test);
+    for (i = 0; i < ninfo; i++)
+        qemuMonitorIOThreadsInfoFree(info[i]);
+    VIR_FREE(info);
+
+    return ret;
+}
+
 static int
 mymain(void)
 {
@@ -2272,6 +2342,7 @@ mymain(void)
     DO_TEST(GetDeviceAliases);
     DO_TEST(CPU);
     DO_TEST(GetNonExistingCPUData);
+    DO_TEST(GetIOThreads);
     DO_TEST_SIMPLE("qmp_capabilities", qemuMonitorJSONSetCapabilities);
     DO_TEST_SIMPLE("system_powerdown", qemuMonitorJSONSystemPowerdown);
     DO_TEST_SIMPLE("system_reset", qemuMonitorJSONSystemReset);