forked from u-root/u-root
/
mknod_linux.go
77 lines (67 loc) · 1.68 KB
/
mknod_linux.go
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// Copyright 2017 the u-root Authors. All rights reserved
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"errors"
"flag"
"fmt"
"strconv"
"golang.org/x/sys/unix"
)
const defaultPerms = 0660
func parseDevices(args []string, devtype string) (int, error) {
if len(args) != 4 {
return 0, fmt.Errorf("device type %v requires a major and minor number", devtype)
}
major, err := strconv.ParseUint(args[2], 10, 12)
if err != nil {
return 0, err
}
minor, err := strconv.ParseUint(args[3], 10, 20)
if err != nil {
return 0, err
}
return int(unix.Mkdev(uint32(major), uint32(minor))), nil
}
func mknod() error {
flag.Parse()
a := flag.Args()
if len(a) != 2 && len(a) != 4 {
return errors.New("Usage: mknod path type [major minor]")
}
path := a[0]
devtype := a[1]
var err error
var mode uint32
mode = defaultPerms
var dev int
switch devtype {
case "b":
// This is a block device. A major/minor number is needed.
mode |= unix.S_IFBLK
dev, err = parseDevices(a, devtype)
if err != nil {
return err
}
case "c", "u":
// This is a character/unbuffered device. A major/minor number is needed.
mode |= unix.S_IFCHR
dev, err = parseDevices(a, devtype)
if err != nil {
return err
}
case "p":
// This is a pipe. A major and minor number must not be supplied
mode |= unix.S_IFIFO
if len(a) != 2 {
return fmt.Errorf("device type %v requires no other arguments", devtype)
}
default:
return fmt.Errorf("device type not recognized: %v", devtype)
}
if err := unix.Mknod(path, mode, dev); err != nil {
return fmt.Errorf("mknod :%s: mode %x: %v", path, mode, err)
}
return nil
}