install: Add reset

This is a nondestructive variant of `to-existing-root`.

Signed-off-by: Colin Walters <[email protected]>

Author: cgwalters

crates/lib/src/cli.rs

@@ -29,7 +29,7 @@ use ostree_ext::sysroot::SysrootLock;
 use schemars::schema_for;
 use serde::{Deserialize, Serialize};
 
-use crate::deploy::RequiredHostSpec;
+use crate::deploy::{MergeState, RequiredHostSpec};
 use crate::lints;
 use crate::progress_jsonl::{ProgressWriter, RawProgressFd};
 use crate::spec::Host;
@@ -256,6 +256,12 @@ pub(crate) enum InstallOpts {
     /// will be wiped, but the content of the existing root will otherwise be retained, and will
     /// need to be cleaned up if desired when rebooted into the new root.
     ToExistingRoot(crate::install::InstallToExistingRootOpts),
+    /// Nondestructively create a fresh installation state inside an existing bootc system.
+    ///
+    /// This is a nondestructive variant of `install to-existing-root` that works only inside
+    /// an existing bootc system.
+    #[clap(hide = true)]
+    Reset(crate::install::InstallResetOpts),
     /// Execute this as the penultimate step of an installation using `install to-filesystem`.
     ///
     Finalize {
@@ -997,8 +1003,9 @@ async fn upgrade(opts: UpgradeOpts) -> Result<()> {
         } else if booted_unchanged {
             println!("No update available.")
         } else {
-            let osname = booted_deployment.osname();
-            crate::deploy::stage(sysroot, &osname, &fetched, &spec, prog.clone()).await?;
+            let stateroot = booted_deployment.osname();
+            let from = MergeState::from_stateroot(sysroot, &stateroot)?;
+            crate::deploy::stage(sysroot, from, &fetched, &spec, prog.clone()).await?;
             changed = true;
             if let Some(prev) = booted_image.as_ref() {
                 if let Some(fetched_manifest) = fetched.get_manifest(repo)? {
@@ -1110,7 +1117,8 @@ async fn switch(opts: SwitchOpts) -> Result<()> {
     }
 
     let stateroot = booted_deployment.osname();
-    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec, prog.clone()).await?;
+    let from = MergeState::from_stateroot(sysroot, &stateroot)?;
+    crate::deploy::stage(sysroot, from, &fetched, &new_spec, prog.clone()).await?;
 
     sysroot.update_mtime()?;
 
@@ -1193,7 +1201,8 @@ async fn edit(opts: EditOpts) -> Result<()> {
     // TODO gc old layers here
 
     let stateroot = booted_deployment.osname();
-    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec, prog.clone()).await?;
+    let from = MergeState::from_stateroot(sysroot, &stateroot)?;
+    crate::deploy::stage(sysroot, from, &fetched, &new_spec, prog.clone()).await?;
 
     sysroot.update_mtime()?;
 
@@ -1379,6 +1388,7 @@ async fn run_from_opt(opt: Opt) -> Result<()> {
             InstallOpts::ToExistingRoot(opts) => {
                 crate::install::install_to_existing_root(opts).await
             }
+            InstallOpts::Reset(opts) => crate::install::install_reset(opts).await,
             InstallOpts::PrintConfiguration => crate::install::print_configuration(),
             InstallOpts::EnsureCompletion {} => {
                 let rootfs = &Dir::open_ambient_dir("/", cap_std::ambient_authority())?;

crates/lib/src/deploy.rs

@@ -577,25 +577,26 @@ pub(crate) fn get_base_commit(repo: &ostree::Repo, commit: &str) -> Result<Optio
 #[context("Writing deployment")]
 async fn deploy(
     sysroot: &Storage,
-    merge_deployment: Option<&Deployment>,
-    stateroot: &str,
+    from: MergeState,
     image: &ImageState,
     origin: &glib::KeyFile,
 ) -> Result<Deployment> {
     // Compute the kernel argument overrides. In practice today this API is always expecting
     // a merge deployment. The kargs code also always looks at the booted root (which
     // is a distinct minor issue, but not super important as right now the install path
     // doesn't use this API).
-    let override_kargs = if let Some(deployment) = merge_deployment {
-        Some(crate::bootc_kargs::get_kargs(sysroot, &deployment, image)?)
-    } else {
-        None
+    let (stateroot, override_kargs) = match &from {
+        MergeState::MergeDeployment(deployment) => {
+            let kargs = crate::kargs::get_kargs(sysroot, &deployment, image)?;
+            (deployment.stateroot().into(), kargs)
+        }
+        MergeState::Reset { stateroot, kargs } => (stateroot.clone(), kargs.clone()),
     };
     // Clone all the things to move to worker thread
     let ostree = sysroot.get_ostree_cloned()?;
     // ostree::Deployment is incorrectly !Send 😢 so convert it to an integer
+    let merge_deployment = from.as_merge_deployment();
     let merge_deployment = merge_deployment.map(|d| d.index() as usize);
-    let stateroot = stateroot.to_string();
     let ostree_commit = image.ostree_commit.to_string();
     // GKeyFile also isn't Send! So we serialize that as a string...
     let origin_data = origin.to_data();
@@ -609,12 +610,11 @@ async fn deploy(
             // Because the C API expects a Vec<&str>, we need to generate a new Vec<>
             // that borrows.
             let override_kargs = override_kargs
-                .as_deref()
-                .map(|v| v.iter().map(|s| s.as_str()).collect::<Vec<_>>());
-            if let Some(kargs) = override_kargs.as_deref() {
-                opts.override_kernel_argv = Some(&kargs);
-            }
-            let deployments = ostree.deployments();
+                .iter()
+                .map(|s| s.as_str())
+                .collect::<Vec<_>>();
+            opts.override_kernel_argv = Some(&override_kargs);
+            let deployments = sysroot.deployments();
             let merge_deployment = merge_deployment.map(|m| &deployments[m]);
             let origin = glib::KeyFile::new();
             origin.load_from_data(&origin_data, glib::KeyFileFlags::NONE)?;
@@ -649,11 +649,41 @@ fn origin_from_imageref(imgref: &ImageReference) -> Result<glib::KeyFile> {
     Ok(origin)
 }
 
+/// The source of data for staging a new deployment
+#[derive(Debug)]
+pub(crate) enum MergeState {
+    /// Use the provided merge deployment
+    MergeDeployment(Deployment),
+    /// Don't use a merge deployment, but only this
+    /// provided initial state.
+    Reset {
+        stateroot: String,
+        kargs: Vec<String>,
+    },
+}
+impl MergeState {
+    /// Initialize using the default merge deployment for the given stateroot.
+    pub(crate) fn from_stateroot(sysroot: &Storage, stateroot: &str) -> Result<Self> {
+        let merge_deployment = sysroot.merge_deployment(Some(stateroot)).ok_or_else(|| {
+            anyhow::anyhow!("No merge deployment found for stateroot {stateroot}")
+        })?;
+        Ok(Self::MergeDeployment(merge_deployment))
+    }
+
+    /// Cast this to a merge deployment case.
+    pub(crate) fn as_merge_deployment(&self) -> Option<&Deployment> {
+        match self {
+            Self::MergeDeployment(d) => Some(d),
+            Self::Reset { .. } => None,
+        }
+    }
+}
+
 /// Stage (queue deployment of) a fetched container image.
 #[context("Staging")]
 pub(crate) async fn stage(
     sysroot: &Storage,
-    stateroot: &str,
+    from: MergeState,
     image: &ImageState,
     spec: &RequiredHostSpec<'_>,
     prog: ProgressWriter,
@@ -694,7 +724,6 @@ pub(crate) async fn stage(
             .collect(),
     })
     .await;
-    let merge_deployment = ostree.merge_deployment(Some(stateroot));
 
     subtask.completed = true;
     subtasks.push(subtask.clone());
@@ -717,14 +746,7 @@ pub(crate) async fn stage(
     })
     .await;
     let origin = origin_from_imageref(spec.image)?;
-    let deployment = crate::deploy::deploy(
-        sysroot,
-        merge_deployment.as_ref(),
-        stateroot,
-        image,
-        &origin,
-    )
-    .await?;
+    let deployment = crate::deploy::deploy(sysroot, from, image, &origin).await?;
 
     subtask.completed = true;
     subtasks.push(subtask.clone());

crates/lib/src/install.rs

@@ -44,7 +44,7 @@ use ostree::gio;
 use ostree_ext::ostree;
 use ostree_ext::ostree_prepareroot::{ComposefsState, Tristate};
 use ostree_ext::prelude::Cast;
-use ostree_ext::sysroot::SysrootLock;
+use ostree_ext::sysroot::{allocate_new_stateroot, list_stateroots, SysrootLock};
 use ostree_ext::{container as ostree_container, ostree_prepareroot};
 #[cfg(feature = "install-to-disk")]
 use rustix::fs::FileTypeExt;
@@ -55,7 +55,10 @@ use serde::{Deserialize, Serialize};
 use self::baseline::InstallBlockDeviceOpts;
 use crate::boundimage::{BoundImage, ResolvedBoundImage};
 use crate::containerenv::ContainerExecutionInfo;
-use crate::deploy::{prepare_for_pull, pull_from_prepared, PreparedImportMeta, PreparedPullResult};
+use crate::deploy::{
+    prepare_for_pull, pull_from_prepared, MergeState, PreparedImportMeta, PreparedPullResult,
+};
+use crate::kernel_cmdline::Cmdline;
 use crate::lsm;
 use crate::progress_jsonl::ProgressWriter;
 use crate::spec::ImageReference;
@@ -352,6 +355,50 @@ pub(crate) struct InstallToExistingRootOpts {
     pub(crate) root_path: Utf8PathBuf,
 }
 
+#[derive(Debug, clap::Parser, PartialEq, Eq)]
+pub(crate) struct InstallResetOpts {
+    /// Acknowledge that this command is experimental.
+    #[clap(long)]
+    pub(crate) experimental: bool,
+
+    #[clap(flatten)]
+    pub(crate) source_opts: InstallSourceOpts,
+
+    #[clap(flatten)]
+    pub(crate) target_opts: InstallTargetOpts,
+
+    /// Name of the target stateroot. If not provided, one will be automatically
+    /// generated of the form s<year>-<serial> where <serial> starts at zero and
+    /// increments automatically.
+    #[clap(long)]
+    pub(crate) stateroot: Option<String>,
+
+    /// Don't display progress
+    #[clap(long)]
+    pub(crate) quiet: bool,
+
+    #[clap(flatten)]
+    pub(crate) progress: crate::cli::ProgressOptions,
+
+    /// Restart or reboot into the new target image.
+    ///
+    /// Currently, this option always reboots.  In the future this command
+    /// will detect the case where no kernel changes are queued, and perform
+    /// a userspace-only restart.
+    #[clap(long)]
+    pub(crate) apply: bool,
+
+    /// Skip inheriting any automatically discovered root file system kernel arguments.
+    #[clap(long)]
+    no_root_kargs: bool,
+
+    /// Add a kernel argument.  This option can be provided multiple times.
+    ///
+    /// Example: --karg=nosmt --karg=console=ttyS0,114800n8
+    #[clap(long)]
+    karg: Option<Vec<String>>,
+}
+
 /// Global state captured from the container.
 #[derive(Debug, Clone)]
 pub(crate) struct SourceInfo {
@@ -385,6 +432,24 @@ pub(crate) struct State {
     pub(crate) tempdir: TempDir,
 }
 
+impl InstallTargetOpts {
+    pub(crate) fn imageref(&self) -> Result<Option<ostree_container::OstreeImageReference>> {
+        let Some(target_imgname) = self.target_imgref.as_deref() else {
+            return Ok(None);
+        };
+        let target_transport =
+            ostree_container::Transport::try_from(self.target_transport.as_str())?;
+        let target_imgref = ostree_container::OstreeImageReference {
+            sigverify: ostree_container::SignatureSource::ContainerPolicyAllowInsecure,
+            imgref: ostree_container::ImageReference {
+                transport: target_transport,
+                name: target_imgname.to_string(),
+            },
+        };
+        Ok(Some(target_imgref))
+    }
+}
+
 impl State {
     #[context("Loading SELinux policy")]
     pub(crate) fn load_policy(&self) -> Result<Option<ostree::SePolicy>> {
@@ -2019,6 +2084,94 @@ pub(crate) async fn install_to_existing_root(opts: InstallToExistingRootOpts) ->
     install_to_filesystem(opts, true, cleanup).await
 }
 
+pub(crate) async fn install_reset(opts: InstallResetOpts) -> Result<()> {
+    let rootfs = &Dir::open_ambient_dir("/", cap_std::ambient_authority())?;
+    if !opts.experimental {
+        anyhow::bail!("This command requires --experimental");
+    }
+
+    let prog: ProgressWriter = opts.progress.try_into()?;
+
+    let sysroot = &crate::cli::get_storage().await?;
+    let repo = &sysroot.repo();
+    let (booted_deployment, _deployments, host) =
+        crate::status::get_status_require_booted(sysroot)?;
+
+    let stateroots = list_stateroots(sysroot)?;
+    dbg!(&stateroots);
+    let target_stateroot = if let Some(s) = opts.stateroot {
+        s
+    } else {
+        let now = chrono::Utc::now();
+        let r = allocate_new_stateroot(&sysroot, &stateroots, now)?;
+        r.name
+    };
+
+    let booted_stateroot = booted_deployment.osname();
+    assert!(booted_stateroot.as_str() != target_stateroot);
+    let (fetched, spec) = if let Some(target) = opts.target_opts.imageref()? {
+        let mut new_spec = host.spec;
+        new_spec.image = Some(target.into());
+        let fetched = crate::deploy::pull(
+            repo,
+            &new_spec.image.as_ref().unwrap(),
+            None,
+            opts.quiet,
+            prog.clone(),
+        )
+        .await?;
+        (fetched, new_spec)
+    } else {
+        let imgstate = host
+            .status
+            .booted
+            .map(|b| b.query_image(repo))
+            .transpose()?
+            .flatten()
+            .ok_or_else(|| anyhow::anyhow!("No image source specified"))?;
+        (Box::new((*imgstate).into()), host.spec)
+    };
+    let spec = crate::deploy::RequiredHostSpec::from_spec(&spec)?;
+
+    // Compute the kernel arguments to inherit. By default, that's only those involved
+    // in the root filesystem.
+    let root_kargs = if opts.no_root_kargs {
+        Vec::new()
+    } else {
+        let bootcfg = booted_deployment
+            .bootconfig()
+            .ok_or_else(|| anyhow!("Missing bootcfg for booted deployment"))?;
+        if let Some(options) = bootcfg.get("options") {
+            let options = options.split_ascii_whitespace().collect::<Vec<_>>();
+            crate::kernel::root_args_from_cmdline(&options)
+                .into_iter()
+                .map(ToOwned::to_owned)
+                .collect::<Vec<_>>()
+        } else {
+            Vec::new()
+        }
+    };
+
+    let kargs = crate::kargs::get_kargs_in_root(rootfs, std::env::consts::ARCH)?
+        .into_iter()
+        .chain(root_kargs.into_iter())
+        .chain(opts.karg.unwrap_or_default())
+        .collect::<Vec<_>>();
+
+    let from = MergeState::Reset {
+        stateroot: target_stateroot,
+        kargs,
+    };
+    crate::deploy::stage(sysroot, from, &fetched, &spec, prog.clone()).await?;
+
+    sysroot.update_mtime()?;
+
+    if opts.apply {
+        crate::reboot::reboot()?;
+    }
+    Ok(())
+}
+
 /// Implementation of `bootc install finalize`.
 pub(crate) async fn install_finalize(target: &Utf8Path) -> Result<()> {
     // Log the installation finalization operation to systemd journal

crates/ostree-ext/src/sysroot.rs

@@ -38,7 +38,6 @@ impl Deref for SysrootLock {
     }
 }
 
-
 /// Access the file descriptor for a sysroot
 #[allow(unsafe_code)]
 pub fn sysroot_fd(sysroot: &ostree::Sysroot) -> BorrowedFd {