ctr: Add helpers to database to check Linux and ARM arch

Weichen81 · Weichen81 · commit 4355ba2f8341 · 2017-12-20T14:49:45.000+08:00
On ARM platforms, we have to prepare the variant for spec.platform.
Currently, this action would only work on Linux/ARM system. We
introduce these two helpers to check running system's OS and Arch.

Change-Id: Iff14087699219413779dd6caf1bf9524db1cc19e
Signed-off-by: Wei Chen &lt;Wei.Chen@arm.com&gt;
diff --git a/platforms/database.go b/platforms/database.go
@@ -5,6 +5,13 @@ import (
 	"strings"
 )
 
+// isLinuxOS returns true if the operating system is Linux.
+//
+// The OS value should be normalized before calling this function.
+func isLinuxOS(os string) bool {
+	return os == "linux"
+}
+
 // These function are generated from from https://golang.org/src/go/build/syslist.go.
 //
 // We use switch statements because they are slightly faster than map lookups
@@ -21,6 +28,17 @@ func isKnownOS(os string) bool {
 	return false
 }
 
+// isArmArch returns true if the architecture is ARM.
+//
+// The arch value should be normalized before being passed to this function.
+func isArmArch(arch string) bool {
+	switch arch {
+	case "arm", "arm64":
+		return true
+	}
+	return false
+}
+
 // isKnownArch returns true if we know about the architecture.
 //
 // The arch value should be normalized before being passed to this function.
