Struct nix::mount::Nmount

pub struct Nmount<'a> { /* private fields */ }

Available on crate feature mount only.

Mount a FreeBSD file system.

The nmount(2) system call works similarly to the mount(8) program; it takes its options as a series of name-value pairs. Most of the values are strings, as are all of the names. The Nmount structure builds up an argument list and then executes the syscall.

Examples

To mount target onto mountpoint with nullfs:

use nix::mount::{MntFlags, Nmount, unmount};
use std::ffi::CString;
use tempfile::tempdir;

let mountpoint = tempdir().unwrap();
let target = tempdir().unwrap();

let fstype = CString::new("fstype").unwrap();
let nullfs = CString::new("nullfs").unwrap();
Nmount::new()
    .str_opt(&fstype, &nullfs)
    .str_opt_owned("fspath", mountpoint.path().to_str().unwrap())
    .str_opt_owned("target", target.path().to_str().unwrap())
    .nmount(MntFlags::empty()).unwrap();

unmount(mountpoint.path(), MntFlags::empty()).unwrap();

See Also

• nmount(2)
• nullfs(5)

Implementations

impl<'a> Nmount<'a>

pub unsafe fn mut_ptr_opt(
    &mut self,
    name: &'a CStr,
    val: *mut c_void,
    len: usize
) -> &mut Self

Add an opaque mount option.

Some file systems take binary-valued mount options. They can be set with this method.

Safety

Unsafe because it will cause Nmount::nmount to dereference a raw pointer. The user is responsible for ensuring that val is valid and its lifetime outlives self! An easy way to do that is to give the value a larger scope than name

Examples

use libc::c_void;
use nix::mount::Nmount;
use std::ffi::CString;
use std::mem;

// Note that flags outlives name
let mut flags: u32 = 0xdeadbeef;
let name = CString::new("flags").unwrap();
let p = &mut flags as *mut u32 as *mut c_void;
let len = mem::size_of_val(&flags);
let mut nmount = Nmount::new();
unsafe { nmount.mut_ptr_opt(&name, p, len) };

pub fn null_opt(&mut self, name: &'a CStr) -> &mut Self

Add a mount option that does not take a value.

Examples

use nix::mount::Nmount;
use std::ffi::CString;

let read_only = CString::new("ro").unwrap();
Nmount::new()
    .null_opt(&read_only);

pub fn null_opt_owned<P: ?Sized + NixPath>(&mut self, name: &P) -> &mut Self

Add a mount option that does not take a value, but whose name must be owned.

This has higher runtime cost than Nmount::null_opt, but is useful when the name’s lifetime doesn’t outlive the Nmount, or it’s a different string type than CStr.

Examples

use nix::mount::Nmount;

let read_only = "ro";
let mut nmount: Nmount<'static> = Nmount::new();
nmount.null_opt_owned(read_only);

pub fn str_opt(&mut self, name: &'a CStr, val: &'a CStr) -> &mut Self

Add a mount option as a CStr.

Examples

use nix::mount::Nmount;
use std::ffi::CString;

let fstype = CString::new("fstype").unwrap();
let nullfs = CString::new("nullfs").unwrap();
Nmount::new()
    .str_opt(&fstype, &nullfs);

pub fn str_opt_owned<P1, P2>(&mut self, name: &P1, val: &P2) -> &mut Selfwhere
    P1: ?Sized + NixPath,
    P2: ?Sized + NixPath,

Add a mount option as an owned string.

This has higher runtime cost than Nmount::str_opt, but is useful when the value’s lifetime doesn’t outlive the Nmount, or it’s a different string type than CStr.

Examples

use nix::mount::Nmount;
use std::path::Path;

let mountpoint = Path::new("/mnt");
Nmount::new()
    .str_opt_owned("fspath", mountpoint.to_str().unwrap());

pub fn new() -> Self

Create a new Nmount struct with no options

pub fn nmount(&mut self, flags: MntFlags) -> NmountResult

Actually mount the file system.

Trait Implementations

impl<'a> Debug for Nmount<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> Default for Nmount<'a>

fn default() -> Nmount<'a>

Returns the “default value” for a type.

impl<'a> Drop for Nmount<'a>

fn drop(&mut self)

Executes the destructor for this type.