system df --verbose don't crash

When a container has no image, i.e. using rootfs like our new infra
containers then the Image function crashed trying to show the first 12
image ID chars. If there is no image simply show nothing there.

Fixes: #26224

Signed-off-by: Paul Holzinger <[email protected]>

Author: Luap99

cmd/podman/system/df.go

@@ -275,7 +275,10 @@ func (d *dfContainer) ContainerID() string {
 }
 
 func (d *dfContainer) Image() string {
-	return d.SystemDfContainerReport.Image[0:12]
+	if len(d.SystemDfContainerReport.Image) >= 12 {
+		return d.SystemDfContainerReport.Image[0:12]
+	}
+	return ""
 }
 
 func (d *dfContainer) Command() string {

test/system/320-system-df.bats

@@ -34,6 +34,23 @@ function setup_file() {
     is "$output" '.*"Local Volumes".*"Size":"0B"' "Total containers reported"
 }
 
+# Regression test for https://github.com/containers/podman/issues/26224
+@test "podman system df - with rootfs container" {
+    pod=p-$(safename)
+    # create a pod which creates an infra container based on a rootfs
+    run_podman pod create --name $pod
+
+    run_podman system df
+    assert "${lines[1]}"  =~ "Images *1 *0.*"
+    assert "${lines[2]}"  =~ "Containers *1 *0.*"
+    run_podman system df --verbose
+    assert "${lines[5]}" =~ \
+       "[0-9a-f]{12} *0.*[0-9a-f]{12}-infra" \
+       "system df --verbose, 'Containers', infra line"
+
+    run_podman pod rm -f $pod
+}
+
 @test "podman system df --format json functionality" {
     # Run two dummy containers, one which exits, one which stays running
     cname_stopped=c-stopped-$(safename)