From 35c56d3f98e4394d37151fd62630b797434aa3ad Mon Sep 17 00:00:00 2001
From: brent saner <brent.saner@gmail.com>
Date: Tue, 7 Oct 2025 17:11:37 -0400
Subject: [PATCH] v1.14.3

ADDED:
* Convenience function to return a namespace FD and its type from a
  namespace ID (Linux only)
---
 errs/errs_linux.go |  9 +++++++++
 funcs_linux.go     | 35 +++++++++++++++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 errs/errs_linux.go

diff --git a/errs/errs_linux.go b/errs/errs_linux.go
new file mode 100644
index 0000000..4c13a46
--- /dev/null
+++ b/errs/errs_linux.go
@@ -0,0 +1,9 @@
+package errs
+
+import (
+	"errors"
+)
+
+var (
+	ErrInvalidNs error = errors.New("invalid namespace identifier")
+)
diff --git a/funcs_linux.go b/funcs_linux.go
index 8de6194..934c450 100644
--- a/funcs_linux.go
+++ b/funcs_linux.go
@@ -1,11 +1,14 @@
 package sysutils
 
 import (
-	`fmt`
-	`os`
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
 
-	`golang.org/x/sys/unix`
-	`r00t2.io/sysutils/envs`
+	"golang.org/x/sys/unix"
+	"r00t2.io/sysutils/envs"
+	"r00t2.io/sysutils/errs"
 )
 
 // GetIDState returns current ID/elevation information. An IDState should *not* be explicitly created/defined.
@@ -48,3 +51,27 @@ func GetIDState() (ids IDState) {
 
 	return
 }
+
+// NsToFD splits a namespace identifier (e.g. `net:[12345]`) to its type (e.g. `net`) and FD (e.g. `12345`).
+func NsToFD(ns string) (typ string, fd uint64, err error) {
+
+	var fields []string
+
+	fields = strings.SplitN(ns, ":", 2)
+
+	if len(fields) != 2 {
+		err = errs.ErrInvalidNs
+		return
+	}
+
+	fields[1] = strings.TrimPrefix(fields[1], "[")
+	fields[1] = strings.TrimSuffix(fields[1], "]")
+
+	if fd, err = strconv.ParseUint(fields[1], 10, 64); err != nil {
+		return
+	}
+
+	typ = fields[0]
+
+	return
+}