Add container information to .containerenv

We have been asked to leak some container information
and image information into the container to be used
by certain tools. (Toolbox and others)

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

Author: rhatdan

run_linux.go

@@ -216,16 +216,23 @@ func (b *Builder) Run(command []string, options RunOptions) error {
 	}
 	// Empty file, so no need to recreate if it exists
 	if _, ok := bindFiles["/run/.containerenv"]; !ok {
-		// Empty string for now, but we may consider populating this later
 		containerenvPath := filepath.Join(path, "/run/.containerenv")
 		if err = os.MkdirAll(filepath.Dir(containerenvPath), 0755); err != nil {
 			return err
 		}
-		emptyFile, err := os.Create(containerenvPath)
-		if err != nil {
+
+		// Populate the .containerenv with container information
+		containerenv := fmt.Sprintf(`\
+engine="buildah-%s"
+name=%q
+id=%q
+image=%q
+imageid=%q
+`, Version, b.Container, b.ContainerID, b.FromImage, b.FromImageID)
+
+		if err = ioutils.AtomicWriteFile(containerenvPath, []byte(containerenv), 0755); err != nil {
 			return err
 		}
-		emptyFile.Close()
 		if err := label.Relabel(containerenvPath, b.MountLabel, false); err != nil {
 			return err
 		}

tests/run.bats

@@ -391,6 +391,15 @@ function configure_and_check_user() {
 	# test a standard mount to /run/.containerenv
 	run_buildah run $cid ls -1 /run/.containerenv
 	expect_output --substring "/run/.containerenv"
+
+	run_buildah run $cid sh -c '. /run/.containerenv; echo $engine'
+	expect_output --substring "buildah"
+
+	run_buildah run $cid sh -c '. /run/.containerenv; echo $name'
+	expect_output "alpine-working-container"
+
+	run_buildah run $cid sh -c '. /run/.containerenv; echo $image'
+	expect_output --substring "alpine:latest"
 }
 
 @test "run-device" {