Files
SukiSU-Ultra/userspace/ksud/src/mount.rs

278 lines
8.5 KiB
Rust

use anyhow::{bail, Ok, Result};
#[cfg(any(target_os = "linux", target_os = "android"))]
use anyhow::Context;
#[cfg(any(target_os = "linux", target_os = "android"))]
use retry::delay::NoDelay;
#[cfg(any(target_os = "linux", target_os = "android"))]
use sys_mount::{unmount, FilesystemType, Mount, MountFlags, Unmount, UnmountFlags};
use crate::defs::KSU_OVERLAY_SOURCE;
use log::{info, warn};
#[cfg(any(target_os = "linux", target_os = "android"))]
use procfs::process::Process;
use std::path::Path;
pub struct AutoMountExt4 {
mnt: String,
#[cfg(any(target_os = "linux", target_os = "android"))]
mount: Option<Mount>,
auto_umount: bool,
}
impl AutoMountExt4 {
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn try_new(src: &str, mnt: &str, auto_umount: bool) -> Result<Self> {
let result = Mount::builder()
.fstype(FilesystemType::from("ext4"))
.flags(MountFlags::empty())
.create_loop(true)
.mount(src, mnt)
.map(|mount| {
Ok(Self {
mnt: mnt.to_string(),
mount: Some(mount),
auto_umount,
})
});
if let Err(e) = result {
println!("- Mount failed: {e}, retry with system mount");
let result = std::process::Command::new("mount")
.arg("-t")
.arg("ext4")
.arg(src)
.arg(mnt)
.status();
if let Err(e) = result {
Err(anyhow::anyhow!(
"mount partition: {src} -> {mnt} failed: {e}"
))
} else {
Ok(Self {
mnt: mnt.to_string(),
mount: None,
auto_umount,
})
}
} else {
result.unwrap()
}
}
#[cfg(not(any(target_os = "linux", target_os = "android")))]
pub fn try_new(_src: &str, _mnt: &str, _auto_umount: bool) -> Result<Self> {
unimplemented!()
}
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn umount(&self) -> Result<()> {
if let Some(ref mount) = self.mount {
mount
.unmount(UnmountFlags::empty())
.map_err(|e| anyhow::anyhow!(e))
} else {
let result = std::process::Command::new("umount").arg(&self.mnt).status();
if let Err(e) = result {
Err(anyhow::anyhow!("umount: {} failed: {e}", self.mnt))
} else {
Ok(())
}
}
}
}
#[cfg(any(target_os = "linux", target_os = "android"))]
impl Drop for AutoMountExt4 {
fn drop(&mut self) {
log::info!(
"AutoMountExt4 drop: {}, auto_umount: {}",
self.mnt,
self.auto_umount
);
if self.auto_umount {
let _ = self.umount();
}
}
}
#[allow(dead_code)]
#[cfg(any(target_os = "linux", target_os = "android"))]
fn mount_image(src: &str, target: &str, autodrop: bool) -> Result<()> {
if autodrop {
Mount::builder()
.fstype(FilesystemType::from("ext4"))
.create_loop(true)
.mount_autodrop(src, target, UnmountFlags::empty())
.with_context(|| format!("Failed to do mount: {src} -> {target}"))?;
} else {
Mount::builder()
.fstype(FilesystemType::from("ext4"))
.mount(src, target)
.with_context(|| format!("Failed to do mount: {src} -> {target}"))?;
}
Ok(())
}
#[allow(dead_code)]
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn mount_ext4(src: &str, target: &str, autodrop: bool) -> Result<()> {
// umount target first.
let _ = umount_dir(target);
let result = retry::retry(NoDelay.take(3), || mount_image(src, target, autodrop));
result
.map_err(|e| anyhow::anyhow!("mount partition: {src} -> {target} failed: {e}"))
.map(|_| ())
}
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn umount_dir(src: &str) -> Result<()> {
unmount(src, UnmountFlags::empty()).with_context(|| format!("Failed to umount {src}"))?;
Ok(())
}
#[cfg(any(target_os = "linux", target_os = "android"))]
fn mount_overlayfs(
lower_dirs: &[String],
lowest: impl AsRef<Path>,
dest: impl AsRef<Path>,
) -> Result<()> {
let options = format!(
"lowerdir={}:{}",
lower_dirs.join(":"),
lowest.as_ref().display()
);
info!(
"mount overlayfs on {}, options={}",
dest.as_ref().display(),
options
);
Mount::builder()
.fstype(FilesystemType::from("overlay"))
.data(&options)
.flags(MountFlags::RDONLY)
.mount(KSU_OVERLAY_SOURCE, dest.as_ref())
.with_context(|| {
format!(
"mount overlayfs on {} options {} failed",
dest.as_ref().display(),
options
)
})?;
Ok(())
}
#[cfg(any(target_os = "linux", target_os = "android"))]
fn bind_mount(from: impl AsRef<Path>, to: impl AsRef<Path>) -> Result<()> {
info!(
"bind mount {} -> {}",
from.as_ref().display(),
to.as_ref().display()
);
Mount::builder()
.flags(MountFlags::BIND)
.mount(from.as_ref(), to.as_ref())
.with_context(|| {
format!(
"bind mount failed: {} -> {}",
from.as_ref().display(),
to.as_ref().display()
)
})?;
Ok(())
}
#[cfg(any(target_os = "linux", target_os = "android"))]
fn mount_overlay_child(
mount_point: &str,
relative: &String,
module_roots: &Vec<String>,
stock_root: &String,
) -> Result<()> {
if !module_roots
.iter()
.any(|lower| Path::new(&format!("{lower}{relative}")).exists())
{
return bind_mount(stock_root, mount_point);
}
if !Path::new(&stock_root).is_dir() {
return Ok(());
}
let mut lower_dirs: Vec<String> = vec![];
for lower in module_roots {
let lower_dir = format!("{lower}{relative}");
let path = Path::new(&lower_dir);
if path.is_dir() {
lower_dirs.push(lower_dir);
} else if path.exists() {
// stock root has been blocked by this file
return Ok(());
}
}
if lower_dirs.is_empty() {
return Ok(());
}
// merge modules and stock
if let Err(e) = mount_overlayfs(&lower_dirs, stock_root, mount_point) {
warn!("failed: {:#}, fallback to bind mount", e);
bind_mount(stock_root, mount_point)?;
}
Ok(())
}
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn mount_overlay(root: &String, module_roots: &Vec<String>) -> Result<()> {
info!("mount overlay for {}", root);
std::env::set_current_dir(root).with_context(|| format!("failed to chdir to {root}"))?;
let stock_root = ".";
// collect child mounts before mounting the root
let mounts = Process::myself()?
.mountinfo()
.with_context(|| "get mountinfo")?;
let mut mount_seq = mounts
.iter()
.filter(|m| {
m.mount_point.starts_with(root) && !Path::new(&root).starts_with(&m.mount_point)
})
.map(|m| m.mount_point.to_str())
.collect::<Vec<_>>();
mount_seq.sort();
mount_seq.dedup();
mount_overlayfs(module_roots, root, root).with_context(|| "mount overlayfs for root failed")?;
for mount_point in mount_seq.iter() {
let Some(mount_point) = mount_point else {
continue;
};
let relative = mount_point.replacen(root, "", 1);
let stock_root: String = format!("{stock_root}{relative}");
if !Path::new(&stock_root).exists() {
continue;
}
if let Err(e) = mount_overlay_child(mount_point, &relative, module_roots, &stock_root) {
warn!(
"failed to mount overlay for child {}: {:#}, revert",
mount_point, e
);
umount_dir(root).with_context(|| format!("failed to revert {root}"))?;
bail!(e);
}
}
Ok(())
}
#[cfg(not(any(target_os = "linux", target_os = "android")))]
pub fn mount_ext4(_src: &str, _target: &str, _autodrop: bool) -> Result<()> {
unimplemented!()
}
#[cfg(not(any(target_os = "linux", target_os = "android")))]
pub fn umount_dir(_src: &str) -> Result<()> {
unimplemented!()
}
#[cfg(not(any(target_os = "linux", target_os = "android")))]
pub fn mount_overlay(_dest: &String, _lower_dirs: &Vec<String>) -> Result<()> {
unimplemented!()
}