mount: replace mountinfo handling with moby/sys/mountinfo

Trying to reduce duplicated effort in maintaining a mountinfo
parser, this patch replaces the local implementation with the
implementation in github.com/moby/sys, which is actively maintained
and contains various optimizations.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

mount/mountinfo.go

@@ -16,41 +16,16 @@
 
 package mount
 
+import "github.com/moby/sys/mountinfo"
+
 // Info reveals information about a particular mounted filesystem. This
 // struct is populated from the content in the /proc/<pid>/mountinfo file.
-type Info struct {
-	// ID is a unique identifier of the mount (may be reused after umount).
-	ID int
+type Info = mountinfo.Info
 
-	// Parent indicates the ID of the mount parent (or of self for the top of the
-	// mount tree).
-	Parent int
-
-	// Major indicates one half of the device ID which identifies the device class.
-	Major int
-
-	// Minor indicates one half of the device ID which identifies a specific
-	// instance of device.
-	Minor int
-
-	// Root of the mount within the filesystem.
-	Root string
-
-	// Mountpoint indicates the mount point relative to the process's root.
-	Mountpoint string
-
-	// Options represents mount-specific options.
-	Options string
-
-	// Optional represents optional fields.
-	Optional string
-
-	// FSType indicates the type of filesystem, such as EXT3.
-	FSType string
-
-	// Source indicates filesystem specific information or "none".
-	Source string
-
-	// VFSOptions represents per super block options.
-	VFSOptions string
+func fromMountinfoSlice(infos []*mountinfo.Info) []Info {
+	out := make([]Info, len(infos))
+	for i, v := range infos {
+		out[i] = *v
+	}
+	return out
 }