qemuMonitorJSONEjectMedia: Don't leak stringified reply

The return value of virJSONValueToString() should be freed when
no longer needed. This is not the case after 256496e1.

==26902== 138 bytes in 2 blocks are definitely lost in loss record 1,051 of 1,239
==26902==    at 0x4C29F80: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==26902==    by 0xAA5F599: strdup (in /lib64/libc-2.21.so)
==26902==    by 0x552BAD9: virStrdup (virstring.c:726)
==26902==    by 0x54F60A7: virJSONValueToString (virjson.c:1790)
==26902==    by 0x1DF6EBB9: qemuMonitorJSONEjectMedia (qemu_monitor_json.c:2225)
==26902==    by 0x1DF57A4C: qemuMonitorEjectMedia (qemu_monitor.c:1985)
==26902==    by 0x1DF1EF2D: qemuDomainChangeEjectableMedia (qemu_hotplug.c:199)
==26902==    by 0x1DF90314: qemuDomainChangeDiskLive (qemu_driver.c:7985)
==26902==    by 0x1DF90476: qemuDomainUpdateDeviceLive (qemu_driver.c:8030)
==26902==    by 0x1DF91ED7: qemuDomainUpdateDeviceFlags (qemu_driver.c:8677)
==26902==    by 0x561785F: virDomainUpdateDeviceFlags (libvirt-domain.c:8559)
==26902==    by 0x134210: remoteDispatchDomainUpdateDeviceFlags (remote_dispatch.h:10966)

==26902== 106 bytes in 1 blocks are definitely lost in loss record 1,033 of 1,239
==26902==    at 0x4C29F80: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==26902==    by 0xAA5F599: strdup (in /lib64/libc-2.21.so)
==26902==    by 0x552BAD9: virStrdup (virstring.c:726)
==26902==    by 0x54F60A7: virJSONValueToString (virjson.c:1790)
==26902==    by 0x1DF6EC0C: qemuMonitorJSONEjectMedia (qemu_monitor_json.c:2227)
==26902==    by 0x1DF57A4C: qemuMonitorEjectMedia (qemu_monitor.c:1985)
==26902==    by 0x1DF1EF2D: qemuDomainChangeEjectableMedia (qemu_hotplug.c:199)
==26902==    by 0x1DF90314: qemuDomainChangeDiskLive (qemu_driver.c:7985)
==26902==    by 0x1DF90476: qemuDomainUpdateDeviceLive (qemu_driver.c:8030)
==26902==    by 0x1DF91ED7: qemuDomainUpdateDeviceFlags (qemu_driver.c:8677)
==26902==    by 0x561785F: virDomainUpdateDeviceFlags (libvirt-domain.c:8559)
==26902==    by 0x134210: remoteDispatchDomainUpdateDeviceFlags (remote_dispatch.h:10966)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_monitor_json.c

@@ -2222,10 +2222,13 @@ int qemuMonitorJSONEjectMedia(qemuMonitorPtr mon,
     if (ret == 0)
         ret = qemuMonitorJSONCheckError(cmd, reply);
 
-    VIR_DEBUG("%s", virJSONValueToString(reply, false));
+    if (ret < 0) {
+        char *replyStr = virJSONValueToString(reply, false);
 
-    if (ret < 0 && c_strcasestr(virJSONValueToString(reply, false), "is locked"))
-        ret = -2;
+        if (c_strcasestr(replyStr, "is locked"))
+            ret = -2;
+        VIR_FREE(replyStr);
+    }
 
     virJSONValueFree(cmd);
     virJSONValueFree(reply);