Move Mount into mount pkg

This moves both the Mount type and mountinfo into a single mount
package.

This also opens up the root of the repo to hold the containerd client
implementation.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

mount/mountinfo_freebsd.go

@@ -0,0 +1,45 @@
+package mount
+
+/*
+#include <sys/param.h>
+#include <sys/ucred.h>
+#include <sys/mount.h>
+*/
+import "C"
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+)
+
+// Self retrieves a list of mounts for the current running process.
+func Self() ([]Info, error) {
+	var rawEntries *C.struct_statfs
+
+	count := int(C.getmntinfo(&rawEntries, C.MNT_WAIT))
+	if count == 0 {
+		return nil, fmt.Errorf("Failed to call getmntinfo")
+	}
+
+	var entries []C.struct_statfs
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&entries))
+	header.Cap = count
+	header.Len = count
+	header.Data = uintptr(unsafe.Pointer(rawEntries))
+
+	var out []Info
+	for _, entry := range entries {
+		var mountinfo Info
+		mountinfo.Mountpoint = C.GoString(&entry.f_mntonname[0])
+		mountinfo.Source = C.GoString(&entry.f_mntfromname[0])
+		mountinfo.FSType = C.GoString(&entry.f_fstypename[0])
+		out = append(out, mountinfo)
+	}
+	return out, nil
+}
+
+// PID collects the mounts for a specific process ID.
+func PID(pid int) ([]Info, error) {
+	return nil, fmt.Errorf("mountinfo.PID is not implemented on freebsd")
+}