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WIP: Add support for --replace-mode=alongside for ostree target
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Ironically our support for `--replace-mode=alongside` breaks
when we're targeting an already extant ostree host, because when
we first blow away the `/boot` directory, this means the ostree
stack loses its knowledge that we're in a booted deployment,
and will attempt to GC it...

ostreedev/ostree-rs-ext@8fa019b
is a key part of the fix for that.

However, a notable improvement we can do here is to grow this
whole thing into a real "factory reset" mode, and this will
be a compelling answer to
coreos/fedora-coreos-tracker#399

To implement this though we need to support configuring the
stateroot and not just hardcode `default`.

Signed-off-by: Omer Tuchfeld <[email protected]>
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@cgwalters @omertuc
cgwalters authored and omertuc committed Oct 8, 2024
1 parent 9d55f15 commit 923b0ed
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Showing 3 changed files with 125 additions and 19 deletions.
95 changes: 78 additions & 17 deletions lib/src/install.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -564,26 +564,34 @@ pub(crate) fn print_configuration() -> Result<()> {
}

#[context("Creating ostree deployment")]
async fn initialize_ostree_root(state: &State, root_setup: &RootSetup) -> Result<Storage> {
async fn initialize_ostree_root(state: &State, root_setup: &RootSetup) -> Result<(Storage, bool)> {
let sepolicy = state.load_policy()?;
let sepolicy = sepolicy.as_ref();
// Load a fd for the mounted target physical root
let rootfs_dir = &root_setup.rootfs_fd;
let rootfs = root_setup.rootfs.as_path();
let cancellable = gio::Cancellable::NONE;

let stateroot = state.stateroot();

let has_ostree = rootfs_dir.try_exists("ostree/repo")?;
if !has_ostree {
Task::new_and_run(
"Initializing ostree layout",
"ostree",
["admin", "init-fs", "--modern", rootfs.as_str()],
)?;
} else {
println!("Reusing extant ostree layout");
let path = ".".into();
let _ = crate::utils::open_dir_remount_rw(rootfs_dir, path)
.context("remounting sysroot as read-write")?;
}

// Ensure that the physical root is labeled.
// Another implementation: https://github.com/coreos/coreos-assembler/blob/3cd3307904593b3a131b81567b13a4d0b6fe7c90/src/create_disk.sh#L295
crate::lsm::ensure_dir_labeled(rootfs_dir, "", Some("/".into()), 0o755.into(), sepolicy)?;

let stateroot = state.stateroot();

Task::new_and_run(
"Initializing ostree layout",
"ostree",
["admin", "init-fs", "--modern", rootfs.as_str()],
)?;

// And also label /boot AKA xbootldr, if it exists
let bootdir = rootfs.join("boot");
if bootdir.try_exists()? {
Expand All @@ -607,9 +615,14 @@ async fn initialize_ostree_root(state: &State, root_setup: &RootSetup) -> Result
let sysroot = ostree::Sysroot::new(Some(&gio::File::for_path(rootfs)));
sysroot.load(cancellable)?;

sysroot
.init_osname(stateroot, cancellable)
.context("initializing stateroot")?;
let stateroot_exists = rootfs_dir.try_exists(format!("ostree/deploy/{stateroot}"))?;
if stateroot_exists {
anyhow::bail!("Cannot redeploy over extant stateroot {stateroot}");
} else {
sysroot
.init_osname(stateroot, cancellable)
.context("initializing stateroot")?;
}

let sysroot_dir = Dir::reopen_dir(&crate::utils::sysroot_fd(&sysroot))?;

Expand Down Expand Up @@ -637,14 +650,15 @@ async fn initialize_ostree_root(state: &State, root_setup: &RootSetup) -> Result
let sysroot = ostree::Sysroot::new(Some(&gio::File::for_path(rootfs)));
sysroot.load(cancellable)?;
let sysroot = SysrootLock::new_from_sysroot(&sysroot).await?;
Storage::new(sysroot, &temp_run)
Ok((Storage::new(sysroot, &temp_run)?, has_ostree))
}

#[context("Creating ostree deployment")]
async fn install_container(
state: &State,
root_setup: &RootSetup,
sysroot: &ostree::Sysroot,
has_ostree: bool,
) -> Result<(ostree::Deployment, InstallAleph)> {
let sepolicy = state.load_policy()?;
let sepolicy = sepolicy.as_ref();
Expand Down Expand Up @@ -730,6 +744,7 @@ async fn install_container(
options.kargs = Some(kargs.as_slice());
options.target_imgref = Some(&state.target_imgref);
options.proxy_cfg = proxy_cfg;
options.no_clean = has_ostree;
let imgstate = crate::utils::async_task_with_spinner(
"Deploying container image",
ostree_container::deploy::deploy(&sysroot, stateroot, &src_imageref, Some(options)),
Expand Down Expand Up @@ -1272,10 +1287,11 @@ async fn install_with_sysroot(
sysroot: &Storage,
boot_uuid: &str,
bound_images: &[crate::boundimage::ResolvedBoundImage],
has_ostree: bool,
) -> Result<()> {
// And actually set up the container in that root, returning a deployment and
// the aleph state (see below).
let (_deployment, aleph) = install_container(state, rootfs, &sysroot).await?;
let (_deployment, aleph) = install_container(state, rootfs, &sysroot, has_ostree).await?;
// Write the aleph data that captures the system state at the time of provisioning for aid in future debugging.
rootfs
.rootfs_fd
Expand Down Expand Up @@ -1336,6 +1352,19 @@ async fn install_to_filesystem_impl(state: &State, rootfs: &mut RootSetup) -> Re
.ok_or_else(|| anyhow!("No uuid for boot/root"))?;
tracing::debug!("boot uuid={boot_uuid}");

// If we're doing an alongside install, then the /dev bootupd sees needs to be the host's.
// What we probably really want to do here is tunnel in the host's /dev properly, but for now
// just copy /dev/disk
if rootfs.skip_finalize {
if !Utf8Path::new("/dev/disk").try_exists()? {
Task::new_and_run(
"Copying host /dev/disk",
"cp",
["-a", "/proc/1/root/dev/disk", "/dev/disk"],
)?;
}
}

let bound_images = if state.config_opts.skip_bound_images {
Vec::new()
} else {
Expand All @@ -1356,8 +1385,16 @@ async fn install_to_filesystem_impl(state: &State, rootfs: &mut RootSetup) -> Re

// Initialize the ostree sysroot (repo, stateroot, etc.)
{
let sysroot = initialize_ostree_root(state, rootfs).await?;
install_with_sysroot(state, rootfs, &sysroot, &boot_uuid, &bound_images).await?;
let (sysroot, has_ostree) = initialize_ostree_root(state, rootfs).await?;
install_with_sysroot(
state,
rootfs,
&sysroot,
&boot_uuid,
&bound_images,
has_ostree,
)
.await?;
// We must drop the sysroot here in order to close any open file
// descriptors.
}
Expand Down Expand Up @@ -1498,7 +1535,8 @@ fn remove_all_in_dir_no_xdev(d: &Dir) -> Result<()> {

#[context("Removing boot directory content")]
fn clean_boot_directories(rootfs: &Dir) -> Result<()> {
let bootdir = rootfs.open_dir(BOOT).context("Opening /boot")?;
let bootdir =
crate::utils::open_dir_remount_rw(rootfs, BOOT.into()).context("Opening /boot")?;
// This should not remove /boot/efi note.
remove_all_in_dir_no_xdev(&bootdir)?;
if ARCH_USES_EFI {
Expand Down Expand Up @@ -1589,12 +1627,35 @@ pub(crate) async fn install_to_filesystem(
if !st.is_dir() {
anyhow::bail!("Not a directory: {root_path}");
}

let inspect = crate::mount::inspect_filesystem(&fsopts.root_path)?;

let alternative_root = fsopts.root_path.join("sysroot");
let root_path = match inspect.source.as_str() {
// Our target filesystem is an overlay, the true root is in `/sysroot`
"overlay" => {
tracing::debug!(
"Overlay filesystem detected, using {alternative_root} instead of {root_path} as target root"
);
&alternative_root
}
_ => root_path,
};
let rootfs_fd = Dir::open_ambient_dir(root_path, cap_std::ambient_authority())
.with_context(|| format!("Opening target root directory {root_path}"))?;

tracing::debug!("Root filesystem: {root_path}");

if let Some(false) = ostree_ext::mountutil::is_mountpoint(&rootfs_fd, ".")? {
anyhow::bail!("Not a mountpoint: {root_path}");
}

let fsopts = {
let mut fsopts = fsopts.clone();
fsopts.root_path = root_path.clone();
fsopts
};

// Gather global state, destructuring the provided options.
// IMPORTANT: We might re-execute the current process in this function (for SELinux among other things)
// IMPORTANT: and hence anything that is done before MUST BE IDEMPOTENT.
Expand Down
6 changes: 5 additions & 1 deletion lib/src/lsm.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -333,7 +333,6 @@ pub(crate) fn ensure_dir_labeled_recurse(
Ok(())
}

/// A wrapper for creating a directory, also optionally setting a SELinux label.
#[cfg(feature = "install")]
pub(crate) fn ensure_dir_labeled(
root: &Dir,
Expand Down Expand Up @@ -365,6 +364,11 @@ pub(crate) fn ensure_dir_labeled(

root.ensure_dir_with(local_destname, &DirBuilder::new())
.with_context(|| format!("Opening {local_destname}"))?;
// tracing::trace!("Rooted at {}", root.canonicalize()
tracing::trace!(
"Going to open {} for fchmod",
local_destname.as_std_path().to_str().unwrap()
);
let dirfd = cap_std_ext::cap_primitives::fs::open(
&root.as_filelike_view(),
local_destname.as_std_path(),
Expand Down
43 changes: 42 additions & 1 deletion lib/src/utils.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,10 +5,13 @@ use std::process::Command;
use std::time::Duration;

use anyhow::{Context, Result};
use cap_std_ext::cap_std::fs::Dir;
use camino::Utf8Path;
use cap_std_ext::{cap_std::fs::Dir, prelude::CapStdExtCommandExt};
use fn_error_context::context;
use ostree::glib;
use ostree_ext::container::SignatureSource;
use ostree_ext::ostree;
use std::os::fd::AsFd;

/// Try to look for keys injected by e.g. rpm-ostree requesting machine-local
/// changes; if any are present, return `true`.
Expand Down Expand Up @@ -55,6 +58,44 @@ pub(crate) fn find_mount_option<'a>(
.next()
}

/// Try to (heuristically) determine if the provided path is a mount root.
pub(crate) fn is_mountpoint(root: &Dir, path: &Utf8Path) -> Result<Option<bool>> {
// https://github.com/systemd/systemd/blob/8fbf0a214e2fe474655b17a4b663122943b55db0/src/basic/mountpoint-util.c#L176
use rustix::fs::{AtFlags, StatxFlags};

// SAFETY(unwrap): We can infallibly convert an i32 into a u64.
let mountroot_flag: u64 = libc::STATX_ATTR_MOUNT_ROOT.try_into().unwrap();
match rustix::fs::statx(
root.as_fd(),
path.as_std_path(),
AtFlags::NO_AUTOMOUNT | AtFlags::SYMLINK_NOFOLLOW,
StatxFlags::empty(),
) {
Ok(r) => {
let present = (r.stx_attributes_mask & mountroot_flag) > 0;
Ok(present.then(|| r.stx_attributes & mountroot_flag > 0))
}
Err(e) if e == rustix::io::Errno::NOSYS => Ok(None),
Err(e) => Err(e.into()),
}
}

/// Given a target directory, if it's a read-only mount, then remount it writable
#[context("Opening {target} with writable mount")]
pub(crate) fn open_dir_remount_rw(root: &Dir, target: &Utf8Path) -> Result<Dir> {
if is_mountpoint(root, target)?.unwrap_or_default() {
tracing::debug!("Target {target} is a mountpoint, remounting rw");
let st = Command::new("mount")
.args(["-o", "remount,rw", target.as_str()])
.cwd_dir(root.try_clone()?)
.status()?;
if !st.success() {
anyhow::bail!("Failed to remount: {st:?}");
}
}
root.open_dir(target).map_err(anyhow::Error::new)
}

pub(crate) fn spawn_editor(tmpf: &tempfile::NamedTempFile) -> Result<()> {
let editor_variables = ["EDITOR"];
// These roughly match https://github.com/systemd/systemd/blob/769ca9ab557b19ee9fb5c5106995506cace4c68f/src/shared/edit-util.c#L275
Expand Down

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