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refactor!: tidy everything up #2

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merged 3 commits into from
Jul 18, 2024
Merged

refactor!: tidy everything up #2

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bb37593
refactor!: tidy everything up
madonuko Jul 10, 2024
29fb46b
chore: cargo clippy
madonuko Jul 14, 2024
f79ed71
Merge branch 'main' into w/refactor
lleyton Jul 18, 2024
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1 change: 1 addition & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ license = "MIT"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
itertools = "0.13.0"
nix = { version = "0.27.1", features = ["fs", "env", "dir", "user", "mount", "sched"] }
sys-mount = "3"
tracing = "0.1.37"
Expand Down
153 changes: 55 additions & 98 deletions src/lib.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use itertools::Itertools;
use std::{
collections::BTreeMap,
collections::HashMap,
error::Error,
fs::File,
os::fd::AsRawFd,
Expand All @@ -15,6 +16,17 @@
pub data: Option<String>,
}

impl Default for MountTarget {
fn default() -> Self {
Self {
target: Default::default(),
fstype: Default::default(),
flags: MountFlags::empty(),
data: Default::default(),
}
}
}

impl MountTarget {
/// Create a new mount object
pub fn new(
Expand All @@ -32,23 +44,11 @@
}

#[tracing::instrument]
pub fn mount(
&self,
source: &PathBuf,
root: &Path,
) -> Result<UnmountDrop<Mount>, std::io::Error> {
pub fn mount(&self, source: &PathBuf, root: &Path) -> std::io::Result<UnmountDrop<Mount>> {
// sanitize target path
let target = self.target.strip_prefix("/").unwrap_or(&self.target);
tracing::info!(?root, "Mounting {:?} to {:?}", source, target);
let target = {
let t = root.join(target);
if !target.exists() {
// create the target directory
std::fs::create_dir_all(&target)?;
}
t
};

tracing::info!(?root, "Mounting {source:?} to {target:?}");
let target = root.join(target);
std::fs::create_dir_all(&target)?;

// nix::mount::mount(
Expand All @@ -60,8 +60,7 @@
// )?;
let mut mount = Mount::builder().flags(self.flags);
if let Some(fstype) = &self.fstype {
let fstype = fstype.as_str();
mount = mount.fstype(FilesystemType::Manual(fstype));
mount = mount.fstype(FilesystemType::Manual(&fstype));

Check warning

Code scanning / clippy

this expression creates a reference which is immediately dereferenced by the compiler Warning

this expression creates a reference which is immediately dereferenced by the compiler
}

if let Some(data) = &self.data {
Expand All @@ -72,7 +71,7 @@
Ok(mount)
}

pub fn umount(&self, root: &Path) -> Result<(), std::io::Error> {
pub fn umount(&self, root: &Path) -> std::io::Result<()> {
// sanitize target path
let target = self.target.strip_prefix("/").unwrap_or(&self.target);
let target = root.join(target);
Expand All @@ -84,35 +83,29 @@

/// Mount Table Struct
/// This is used to mount filesystems inside the container. It is essentially an fstab, for the container.
// #[derive(Debug)]
#[derive(Default)]
pub struct MountTable {
/// The table of mounts
/// The key is the device name, and value is the mount object
inner: BTreeMap<PathBuf, MountTarget>,
inner: HashMap<PathBuf, MountTarget>,
mounts: Vec<UnmountDrop<Mount>>,
}

impl Default for MountTable {
fn default() -> Self {
Self::new()
}
}

impl MountTable {
pub fn new() -> Self {
Self {
inner: BTreeMap::new(),
inner: HashMap::new(),
mounts: Vec::new(),
}
}
/// Sets the mount table
pub fn set_table(&mut self, table: BTreeMap<PathBuf, MountTarget>) {
pub fn set_table(&mut self, table: HashMap<PathBuf, MountTarget>) {
self.inner = table;
}

/// Adds a mount to the table
pub fn add_mount(&mut self, mount: MountTarget, source: &Path) {
self.inner.insert(source.to_path_buf(), mount);
pub fn add_mount(&mut self, mount: MountTarget, source: PathBuf) {
self.inner.insert(source, mount);
}

pub fn add_sysmount(&mut self, mount: UnmountDrop<Mount>) {
Expand All @@ -122,26 +115,19 @@
/// Sort mounts by mountpoint and depth
/// Closer to root, and root is first
/// everything else is either sorted by depth, or alphabetically
fn sort_mounts(&self) -> Vec<(&PathBuf, &MountTarget)> {
let mut mounts: Vec<(&PathBuf, &MountTarget)> = self.inner.iter().collect();
mounts.sort_unstable_by(|(_, a), (_, b)| {
let am = a.target.display().to_string().matches('/').count();
let bm = b.target.display().to_string().matches('/').count();
if a.target.display().to_string() == "/" {
std::cmp::Ordering::Less
} else if b.target.display().to_string() == "/" {
std::cmp::Ordering::Greater
} else if am == bm {
a.target.cmp(&b.target)
} else {
am.cmp(&bm)
fn sort_mounts(&self) -> impl Iterator<Item = (&PathBuf, &MountTarget)> {
self.inner.iter().sorted_unstable_by(|(_, a), (_, b)| {
match (a.target.components().count(), b.target.components().count()) {
(1, _) => std::cmp::Ordering::Less, // root dir
(_, 1) => std::cmp::Ordering::Greater, // root dir
(x, y) if x == y => a.target.cmp(&b.target),
(x, y) => x.cmp(&y),
}
});
mounts
})
}

/// Mounts everything to the root
pub fn mount_chroot(&mut self, root: &Path) -> Result<(), std::io::Error> {
pub fn mount_chroot(&mut self, root: &Path) -> std::io::Result<()> {
// let ordered = self.sort_mounts();
// for (source, mount) in ordered {
// let m = mount.mount(source, root)?;
Expand All @@ -150,30 +136,21 @@
//
self.mounts = self
.sort_mounts()
.iter()
.map(|(source, mount)| {
tracing::trace!(?mount, ?source, "Mounting");
// make source if not exists
if !root.join(source).exists() {
std::fs::create_dir_all(root.join(source)).unwrap();
}
mount.mount(source, root).unwrap()
std::fs::create_dir_all(root.join(source))?;
mount.mount(source, root)
})
.collect();
.collect::<std::io::Result<_>>()?;
Ok(())
}

pub fn umount_chroot(&mut self) -> Result<(), std::io::Error> {
// let ordered = self.sort_mounts();
let flags = UnmountFlags::DETACH;
// why is it not unmounting properly
self.mounts.drain(..).rev().for_each(|mount| {
pub fn umount_chroot(&mut self) -> std::io::Result<()> {
self.mounts.drain(..).rev().try_for_each(|mount| {
tracing::trace!("Unmounting {:?}", mount.target_path());
// this causes ENOENT when not chrooting properly
mount.unmount(flags).unwrap();
drop(mount);
});
Ok(())
mount.unmount(UnmountFlags::DETACH)
})
}
}

Expand All @@ -197,7 +174,7 @@
/// This makes use of the `chroot` syscall to enter the chroot jail.
///
#[inline(always)]
pub fn chroot(&mut self) -> Result<(), std::io::Error> {
pub fn chroot(&mut self) -> std::io::Result<()> {
if !self._initialized {
// mount the tmpfs first, idiot proofing in case the
// programmer forgets to mount it before chrooting
Expand All @@ -222,7 +199,7 @@
/// We then also take the pwd stored earlier and move back to it,
/// for good measure.
#[inline(always)]
pub fn exit_chroot(&mut self) -> Result<(), std::io::Error> {
pub fn exit_chroot(&mut self) -> std::io::Result<()> {
nix::unistd::fchdir(self.sysroot.as_raw_fd())?;
nix::unistd::chroot(".")?;
self.chroot = false;
Expand Down Expand Up @@ -281,14 +258,14 @@
}

/// Start mounting files inside the container
pub fn mount(&mut self) -> Result<(), std::io::Error> {
pub fn mount(&mut self) -> std::io::Result<()> {
self.mount_table.mount_chroot(&self.root)?;
self._initialized = true;
Ok(())
}

/// Unmounts all mountpoints inside the container
pub fn umount(&mut self) -> Result<(), std::io::Error> {
pub fn umount(&mut self) -> std::io::Result<()> {
self.mount_table.umount_chroot()?;
self._initialized = false;
Ok(())
Expand All @@ -297,18 +274,17 @@
/// Adds a bind mount for the system's root filesystem to
/// the container's root filesystem at `/run/host`
pub fn host_bind_mount(&mut self) -> &mut Self {
self.bind_mount(&PathBuf::from("/"), &PathBuf::from("/run/host"));
self.bind_mount(PathBuf::from("/"), PathBuf::from("/run/host"));
self
}

/// Adds a bind mount to a file or directory inside the container
pub fn bind_mount(&mut self, source: &Path, target: &Path) {
pub fn bind_mount(&mut self, source: PathBuf, target: PathBuf) {
self.mount_table.add_mount(
MountTarget {
target: target.to_owned(),
fstype: None,
target,
flags: MountFlags::BIND,
data: None,
..MountTarget::default()
},
source,
);
Expand All @@ -317,7 +293,7 @@
/// Adds an additional mount target to the container mount table
///
/// Useful for mounting disks or other filesystems
pub fn add_mount(&mut self, mount: MountTarget, source: &Path) {
pub fn add_mount(&mut self, mount: MountTarget, source: PathBuf) {
self.mount_table.add_mount(mount, source);
}

Expand All @@ -326,41 +302,22 @@
MountTarget {
target: "proc".into(),
fstype: Some("proc".to_string()),
flags: MountFlags::empty(),
data: None,
..MountTarget::default()
},
Path::new("/proc"),
PathBuf::from("/proc"),
);

self.mount_table.add_mount(
MountTarget {
target: "sys".into(),
fstype: Some("sysfs".to_string()),
flags: MountFlags::empty(),
data: None,
},
Path::new("/sys"),
);

self.mount_table.add_mount(
MountTarget {
target: "dev".into(),
fstype: None,
flags: MountFlags::BIND,
data: None,
..MountTarget::default()
},
Path::new("/dev"),
PathBuf::from("/sys"),
);

self.mount_table.add_mount(
MountTarget {
target: "dev/pts".into(),
fstype: None,
flags: MountFlags::BIND,
data: None,
},
Path::new("/dev/pts"),
);
self.bind_mount("/dev".into(), "dev".into());
self.bind_mount("/dev/pts".into(), "dev/pts".into());
}
}

Expand Down