Make temporary names container/image specific

If you hit Ctr-C while pulling an image files and directories get
left in /var/tmp. By adding "containers_images" prefix, we can use
systemd tmpfiles handling to remove them on reboot safely.

Help to make https://github.com/containers/podman/pull/19201 safer.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

docker/internal/tarfile/reader.go

@@ -57,7 +57,7 @@ func NewReaderFromFile(sys *types.SystemContext, path string) (*Reader, error) {
 // The caller should call .Close() on the returned archive when done.
 func NewReaderFromStream(sys *types.SystemContext, inputStream io.Reader) (*Reader, error) {
 	// Save inputStream to a temporary file
-	tarCopyFile, err := os.CreateTemp(tmpdir.TemporaryDirectoryForBigFiles(sys), "docker-tar")
+	tarCopyFile, err := tmpdir.CreateBigFileTemp(sys, "docker-tar")
 	if err != nil {
 		return nil, fmt.Errorf("creating temporary file: %w", err)
 	}

internal/streamdigest/stream_digest.go

@@ -15,7 +15,7 @@ import (
 // It is the caller's responsibility to call the cleanup function, which closes and removes the temporary file.
 // If an error occurs, inputInfo is not modified.
 func ComputeBlobInfo(sys *types.SystemContext, stream io.Reader, inputInfo *types.BlobInfo) (io.Reader, func(), error) {
-	diskBlob, err := os.CreateTemp(tmpdir.TemporaryDirectoryForBigFiles(sys), "stream-blob")
+	diskBlob, err := tmpdir.CreateBigFileTemp(sys, "stream-blob")
 	if err != nil {
 		return nil, nil, fmt.Errorf("creating temporary on-disk layer: %w", err)
 	}

internal/tmpdir/tmpdir.go

@@ -17,10 +17,12 @@ var unixTempDirForBigFiles = builtinUnixTempDirForBigFiles
 // DO NOT change this, instead see unixTempDirForBigFiles above.
 const builtinUnixTempDirForBigFiles = "/var/tmp"
 
+const prefix = "container_images_"
+
 // TemporaryDirectoryForBigFiles returns a directory for temporary (big) files.
 // On non Windows systems it avoids the use of os.TempDir(), because the default temporary directory usually falls under /tmp
 // which on systemd based systems could be the unsuitable tmpfs filesystem.
-func TemporaryDirectoryForBigFiles(sys *types.SystemContext) string {
+func temporaryDirectoryForBigFiles(sys *types.SystemContext) string {
 	if sys != nil && sys.BigFilesTemporaryDir != "" {
 		return sys.BigFilesTemporaryDir
 	}
@@ -32,3 +34,11 @@ func TemporaryDirectoryForBigFiles(sys *types.SystemContext) string {
 	}
 	return temporaryDirectoryForBigFiles
 }
+
+func CreateBigFileTemp(sys *types.SystemContext, name string) (*os.File, error) {
+	return os.CreateTemp(temporaryDirectoryForBigFiles(sys), prefix+name)
+}
+
+func MkDirBigFileTemp(sys *types.SystemContext, name string) (string, error) {
+	return os.MkdirTemp(temporaryDirectoryForBigFiles(sys), prefix+name)
+}

internal/tmpdir/tmpdir_test.go

@@ -0,0 +1,54 @@
+package tmpdir
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/containers/image/v5/types"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateBigFileTemp(t *testing.T) {
+	f, err := CreateBigFileTemp(nil, "")
+	assert.NoError(t, err)
+	f.Close()
+	os.Remove(f.Name())
+
+	f, err = CreateBigFileTemp(nil, "foobar")
+	assert.NoError(t, err)
+	f.Close()
+	assert.True(t, strings.Contains(f.Name(), prefix+"foobar"))
+	os.Remove(f.Name())
+
+	var sys types.SystemContext
+	sys.BigFilesTemporaryDir = "/tmp"
+	f, err = CreateBigFileTemp(&sys, "foobar1")
+	assert.NoError(t, err)
+	f.Close()
+	assert.True(t, strings.Contains(f.Name(), "/tmp/"+prefix+"foobar1"))
+	os.Remove(f.Name())
+
+	sys.BigFilesTemporaryDir = "/tmp/bogus"
+	_, err = CreateBigFileTemp(&sys, "foobar1")
+	assert.Error(t, err)
+
+}
+
+func TestMkDirBigFileTemp(t *testing.T) {
+	d, err := MkDirBigFileTemp(nil, "foobar")
+	assert.NoError(t, err)
+	assert.True(t, strings.Contains(d, prefix+"foobar"))
+	os.RemoveAll(d)
+
+	var sys types.SystemContext
+	sys.BigFilesTemporaryDir = "/tmp"
+	d, err = MkDirBigFileTemp(&sys, "foobar1")
+	assert.NoError(t, err)
+	assert.True(t, strings.Contains(d, "/tmp/"+prefix+"foobar1"))
+	os.RemoveAll(d)
+
+	sys.BigFilesTemporaryDir = "/tmp/bogus"
+	_, err = MkDirBigFileTemp(&sys, "foobar1")
+	assert.Error(t, err)
+}

oci/archive/oci_transport.go

@@ -156,7 +156,7 @@ func (t *tempDirOCIRef) deleteTempDir() error {
 // createOCIRef creates the oci reference of the image
 // If SystemContext.BigFilesTemporaryDir not "", overrides the temporary directory to use for storing big files
 func createOCIRef(sys *types.SystemContext, image string) (tempDirOCIRef, error) {
-	dir, err := os.MkdirTemp(tmpdir.TemporaryDirectoryForBigFiles(sys), "oci")
+	dir, err := tmpdir.MkDirBigFileTemp(sys, "oci")
 	if err != nil {
 		return tempDirOCIRef{}, fmt.Errorf("creating temp directory: %w", err)
 	}

sif/src.go

@@ -73,7 +73,7 @@ func newImageSource(ctx context.Context, sys *types.SystemContext, ref sifRefere
 		_ = sifImg.UnloadContainer()
 	}()
 
-	workDir, err := os.MkdirTemp(tmpdir.TemporaryDirectoryForBigFiles(sys), "sif")
+	workDir, err := tmpdir.MkDirBigFileTemp(sys, "sif")
 	if err != nil {
 		return nil, fmt.Errorf("creating temp directory: %w", err)
 	}

storage/storage_dest.go

@@ -95,7 +95,7 @@ type addedLayerInfo struct {
 // newImageDestination sets us up to write a new image, caching blobs in a temporary directory until
 // it's time to Commit() the image
 func newImageDestination(sys *types.SystemContext, imageRef storageReference) (*storageImageDestination, error) {
-	directory, err := os.MkdirTemp(tmpdir.TemporaryDirectoryForBigFiles(sys), "storage")
+	directory, err := tmpdir.MkDirBigFileTemp(sys, "storage")
 	if err != nil {
 		return nil, fmt.Errorf("creating a temporary directory: %w", err)
 	}

storage/storage_src.go

@@ -124,7 +124,7 @@ func (s *storageImageSource) GetBlob(ctx context.Context, info types.BlobInfo, c
 	}
 	defer rc.Close()
 
-	tmpFile, err := os.CreateTemp(tmpdir.TemporaryDirectoryForBigFiles(s.systemContext), "")
+	tmpFile, err := tmpdir.CreateBigFileTemp(s.systemContext, "")
 	if err != nil {
 		return nil, 0, err
 	}