Fix handling of .containenv on tmpfs

Fixes: containers#18531

Signed-off-by: Daniel J Walsh <[email protected]>

docs/source/markdown/podman-run.1.md.in

@@ -31,7 +31,7 @@ file is created in each container to indicate to programs they are running in a
 container. This file is located at _/run/.containerenv_. When using the
 --privileged flag the .containerenv contains name/value pairs indicating the
 container engine version, whether the engine is running in rootless mode, the
-container name and ID, as well as the image name and ID that the container is based on.
+container name and ID, as well as the image name and ID that the container is based on. Note: _/run/.containerenv_ will not be created when a volume is mounted on /run.
 
 When running from a user defined network namespace, the _/etc/netns/NSNAME/resolv.conf_
 will be used if it exists, otherwise _/etc/resolv.conf_ will be used.

libpod/container_internal_common.go

@@ -1938,11 +1938,16 @@ func (c *Container) makeBindMounts() error {
 
 	_, hasRunContainerenv := c.state.BindMounts["/run/.containerenv"]
 	if !hasRunContainerenv {
+	Loop:
 		// check in the spec mounts
 		for _, m := range c.config.Spec.Mounts {
-			if m.Destination == "/run/.containerenv" || m.Destination == "/run" {
+			switch {
+			case m.Destination == "/run/.containerenv":
 				hasRunContainerenv = true
-				break
+				break Loop
+			case m.Destination == "/run" && m.Source != "tmpfs":
+				hasRunContainerenv = true
+				break Loop
 			}
 		}
 	}

test/system/030-run.bats

@@ -568,8 +568,13 @@ json-file | f
 
 @test "Verify /run/.containerenv exist" {
     # Nonprivileged container: file exists, but must be empty
-    run_podman run --rm $IMAGE stat -c '%s' /run/.containerenv
-    is "$output" "0" "file size of /run/.containerenv, nonprivileged"
+    for opt in "" "--tmpfs=/run" "--tmpfs=/run --init" "--read-only" "--systemd=always"; do
+        run_podman run --rm $opt $IMAGE stat -c '%s' /run/.containerenv
+        is "$output" "0" "/run/.containerenv exists and is empty: podman run ${opt}"
+    done
+
+    run_podman 1 run --rm -v ${PODMAN_TMPDIR}:/run:Z $IMAGE stat -c '%s' /run/.containerenv
+    is "$output" "stat: can't stat '/run/.containerenv': No such file or directory" "do not create .containerenv on bind mounts"
 
     # Prep work: get ID of image; make a cont. name; determine if we're rootless
     run_podman inspect --format '{{.ID}}' $IMAGE