1 files changed, 56 insertions, 0 deletions
diff --git a/volume/volume_linux.go b/volume/volume_linux.go
new file mode 100644
index 0000000..d4b4d80
--- /dev/null
+++ b/volume/volume_linux.go
@@ -0,0 +1,56 @@
+// +build linux
+
+package volume
+
+import (
+	"fmt"
+	"strings"
+
+	mounttypes "github.com/docker/docker/api/types/mount"
+)
+
+// ConvertTmpfsOptions converts *mounttypes.TmpfsOptions to the raw option string
+// for mount(2).
+func ConvertTmpfsOptions(opt *mounttypes.TmpfsOptions, readOnly bool) (string, error) {
+	var rawOpts []string
+	if readOnly {
+		rawOpts = append(rawOpts, "ro")
+	}
+
+	if opt != nil && opt.Mode != 0 {
+		rawOpts = append(rawOpts, fmt.Sprintf("mode=%o", opt.Mode))
+	}
+
+	if opt != nil && opt.SizeBytes != 0 {
+		// calculate suffix here, making this linux specific, but that is
+		// okay, since API is that way anyways.
+
+		// we do this by finding the suffix that divides evenly into the
+		// value, returing the value itself, with no suffix, if it fails.
+		//
+		// For the most part, we don't enforce any semantic to this values.
+		// The operating system will usually align this and enforce minimum
+		// and maximums.
+		var (
+			size   = opt.SizeBytes
+			suffix string
+		)
+		for _, r := range []struct {
+			suffix  string
+			divisor int64
+		}{
+			{"g", 1 << 30},
+			{"m", 1 << 20},
+			{"k", 1 << 10},
+		} {
+			if size%r.divisor == 0 {
+				size = size / r.divisor
+				suffix = r.suffix
+				break
+			}
+		}
+
+		rawOpts = append(rawOpts, fmt.Sprintf("size=%d%s", size, suffix))
+	}
+	return strings.Join(rawOpts, ","), nil
+}