Nothing in daemon code is prepared for the command in
virDomainQemuMonitorCommandWithFiles() to be NULL. In fact, the
client side doesn't expect this either as our RPC describes the
argument as:

    remote_nonnull_string cmd;

Validate the argument in the public API implementation.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/libvirt-qemu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/libvirt-qemu.c b/src/libvirt-qemu.c
index 9e80577b56..c4f71c0311 100644
--- a/src/libvirt-qemu.c
+++ b/src/libvirt-qemu.c
@@ -153,6 +153,8 @@ virDomainQemuMonitorCommandWithFiles(virDomainPtr domain,
     virCheckDomainReturn(domain, -1);
     conn = domain->conn;
 
+    virCheckNonNullArgGoto(cmd, error);
+
     if (ninfiles > 0 || outfiles) {
         int rc;
         if ((rc = VIR_DRV_SUPPORTS_FEATURE(conn->driver, conn,
-- 
2.34.1