add /usr/lib/bootc/kargs.d support

Fixes #255. Allows users to
create files within /usr/lib/bootc/kargs.d with kernel arguments. These
arguments can now be applied on a switch, upgrade, or edit.

General process:
- use ostree commit of fetched container image to return
the file tree
- navigate to /usr/lib/bootc/kargs.d
- read each file within the directory
- push the contents of each file (kargs) into a vector containing all
the desired kargs
- pass the kargs to the stage() function

Signed-off-by: Luke Yang <luyang@redhat.com>

lib/src/cli.rs

@@ -357,6 +357,7 @@ async fn upgrade(opts: UpgradeOpts) -> Result<()> {
         }
     } else {
         let fetched = crate::deploy::pull(sysroot, imgref, opts.quiet).await?;
+        let mut kargs = crate::deploy::get_kargs(repo, fetched.as_ref())?;
         let staged_digest = staged_image.as_ref().map(|s| s.image_digest.as_str());
         let fetched_digest = fetched.manifest_digest.as_str();
         tracing::debug!("staged: {staged_digest:?}");
@@ -378,7 +379,12 @@ async fn upgrade(opts: UpgradeOpts) -> Result<()> {
             println!("No update available.")
         } else {
             let osname = booted_deployment.osname();
-            crate::deploy::stage(sysroot, &osname, &fetched, &spec).await?;
+            let mut opts = ostree::SysrootDeployTreeOpts::default();
+            let mut kargs: Vec<&str> = kargs.iter_mut().map(|s| { let s = s.trim(); s }).collect();
+            kargs.sort();
+            kargs.dedup();
+            opts.override_kernel_argv = Some(kargs.as_slice());
+            crate::deploy::stage(sysroot, &osname, &fetched, &spec, Some(opts)).await?;
             changed = true;
             if let Some(prev) = booted_image.as_ref() {
                 if let Some(fetched_manifest) = fetched.get_manifest(repo)? {
@@ -451,6 +457,7 @@ async fn switch(opts: SwitchOpts) -> Result<()> {
     let new_spec = RequiredHostSpec::from_spec(&new_spec)?;
 
     let fetched = crate::deploy::pull(sysroot, &target, opts.quiet).await?;
+    let mut kargs = crate::deploy::get_kargs(repo, fetched.as_ref())?;
 
     if !opts.retain {
         // By default, we prune the previous ostree ref so it will go away after later upgrades
@@ -464,7 +471,12 @@ async fn switch(opts: SwitchOpts) -> Result<()> {
     }
 
     let stateroot = booted_deployment.osname();
-    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec).await?;
+    let mut opts = ostree::SysrootDeployTreeOpts::default();
+    let mut kargs: Vec<&str> = kargs.iter_mut().map(|s| { let s = s.trim(); s }).collect();
+    kargs.sort();
+    kargs.dedup();
+    opts.override_kernel_argv = Some(kargs.as_slice());
+    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec, Some(opts)).await?;
 
     Ok(())
 }
@@ -493,11 +505,18 @@ async fn edit(opts: EditOpts) -> Result<()> {
     }
     let new_spec = RequiredHostSpec::from_spec(&new_host.spec)?;
     let fetched = crate::deploy::pull(sysroot, new_spec.image, opts.quiet).await?;
+    let repo = &sysroot.repo();
+    let mut kargs = crate::deploy::get_kargs(repo, fetched.as_ref())?;
 
     // TODO gc old layers here
 
     let stateroot = booted_deployment.osname();
-    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec).await?;
+    let mut opts = ostree::SysrootDeployTreeOpts::default();
+    let mut kargs: Vec<&str> = kargs.iter_mut().map(|s| { let s = s.trim(); s }).collect();
+    kargs.sort();
+    kargs.dedup();
+    opts.override_kernel_argv = Some(kargs.as_slice());
+    crate::deploy::stage(sysroot, &stateroot, &fetched, &new_spec, Some(opts)).await?;
 
     Ok(())
 }

lib/src/deploy.rs

@@ -16,6 +16,9 @@ use ostree_ext::container::store::PrepareResult;
 use ostree_ext::ostree;
 use ostree_ext::ostree::Deployment;
 use ostree_ext::sysroot::SysrootLock;
+use ostree_ext::prelude::FileExt;
+use ostree_ext::prelude::Cast;
+use ostree_ext::prelude::FileEnumeratorExt;
 
 use crate::spec::HostSpec;
 use crate::spec::ImageReference;
@@ -219,16 +222,18 @@ async fn deploy(
     stateroot: &str,
     image: &ImageState,
     origin: &glib::KeyFile,
+    opts: Option<ostree::SysrootDeployTreeOpts<'_>>,
 ) -> Result<()> {
     let stateroot = Some(stateroot);
+    let opts = opts.unwrap_or(Default::default());
     // Copy to move into thread
     let cancellable = gio::Cancellable::NONE;
     let _new_deployment = sysroot.stage_tree_with_options(
         stateroot,
         image.ostree_commit.as_str(),
         Some(origin),
         merge_deployment,
-        &Default::default(),
+        &opts,
         cancellable,
     )?;
     Ok(())
@@ -253,6 +258,7 @@ pub(crate) async fn stage(
     stateroot: &str,
     image: &ImageState,
     spec: &RequiredHostSpec<'_>,
+    opts: Option<ostree::SysrootDeployTreeOpts<'_>>,
 ) -> Result<()> {
     let merge_deployment = sysroot.merge_deployment(Some(stateroot));
     let origin = origin_from_imageref(spec.image)?;
@@ -262,6 +268,7 @@ pub(crate) async fn stage(
         stateroot,
         image,
         &origin,
+        opts,
     )
     .await?;
     crate::deploy::cleanup(sysroot).await?;
@@ -340,6 +347,47 @@ pub(crate) fn switch_origin_inplace(root: &Dir, imgref: &ImageReference) -> Resu
     Ok(newest_deployment)
 }
 
+pub fn get_kargs(repo: &ostree::Repo, fetched: &ImageState) -> Result<Vec<String>> {
+    let cancellable = gio::Cancellable::NONE;
+    let (fetched_tree, _) = repo.read_commit(fetched.ostree_commit.as_str(), cancellable)?;
+    let fetched_tree = fetched_tree.resolve_relative_path("/usr/lib/bootc/kargs.d");
+    let fetched_tree = fetched_tree.downcast::<ostree::RepoFile>().expect("downcast");
+    match fetched_tree.query_exists(cancellable) {
+        true => {}
+        false => {
+            return Ok(vec![]);
+        }
+    }
+
+    let mut kargs = vec![];
+    let queryattrs = "standard::name,standard::type";
+    let queryflags = gio::FileQueryInfoFlags::NOFOLLOW_SYMLINKS;
+    let fetched_iter = fetched_tree.enumerate_children(queryattrs, queryflags, cancellable)?;
+    while let Some(fetched_info) = fetched_iter.next_file(cancellable)? {
+        let fetched_child = fetched_iter.child(&fetched_info);
+        let fetched_child = fetched_child.downcast::<ostree::RepoFile>().expect("downcast");
+        fetched_child.ensure_resolved()?;
+        let fetched_contents_checksum = fetched_child.checksum();
+        let f = ostree::Repo::load_file(repo, fetched_contents_checksum.as_str(), cancellable)?;
+        let file_content = f.0;
+        let mut buffer = vec![];
+        let mut reader = ostree_ext::prelude::InputStreamExtManual::into_read(file_content.unwrap());
+        let _ = std::io::Read::read_to_end(&mut reader, &mut buffer);
+        let s = std::string::String::from_utf8(buffer)?;
+        kargs.push(s);
+    }
+
+    let existing_kargs = ostree::KernelArgs::new();
+    ostree::KernelArgs::append_proc_cmdline(
+        &existing_kargs,
+        cancellable,
+    )?;
+    let mut existing_kargs = existing_kargs.to_strv().iter().map(|s| { s.as_str().to_string() }).collect();
+    kargs.append(&mut existing_kargs);
+
+    Ok(kargs)
+}
+
 #[test]
 fn test_switch_inplace() -> Result<()> {
     use cap_std::fs::DirBuilderExt;