adopt: fix adoption when booting with BIOS firmware without ESP

We should support adoption when :
- booting with BIOS firmware without ESP
- booting with UEFI firmware without BIOS BOOT part

Fix regression issue coreos#943,
which is introduced by coreos@fe53bab

Author: HuijingHei

src/bios.rs

@@ -161,10 +161,10 @@ impl Component for Bios {
         &self,
         rootcxt: &RootContext,
         update: &ContentMetadata,
-    ) -> Result<InstalledContent> {
+    ) -> Result<Option<InstalledContent>> {
         let bios_devices = blockdev::find_colocated_bios_boot(&rootcxt.devices)?;
         let Some(meta) = self.query_adopt(&bios_devices)? else {
-            anyhow::bail!("Failed to find adoptable system")
+            return Ok(None);
         };
 
         let mut parent_devices = rootcxt.devices.iter();
@@ -179,11 +179,11 @@ impl Component for Bios {
         }
         self.run_grub_install(rootcxt.path.as_str(), &parent)?;
         log::debug!("Installed grub modules on {parent}");
-        Ok(InstalledContent {
+        Ok(Some(InstalledContent {
             meta: update.clone(),
             filetree: None,
             adopted_from: Some(meta.version),
-        })
+        }))
     }
 
     fn query_update(&self, sysroot: &openat::Dir) -> Result<Option<ContentMetadata>> {

src/bootupd.rs

@@ -258,7 +258,10 @@ pub(crate) fn update(name: &str, rootcxt: &RootContext) -> Result<ComponentUpdat
 }
 
 /// daemon implementation of component adoption
-pub(crate) fn adopt_and_update(name: &str, rootcxt: &RootContext) -> Result<ContentMetadata> {
+pub(crate) fn adopt_and_update(
+    name: &str,
+    rootcxt: &RootContext,
+) -> Result<Option<ContentMetadata>> {
     let sysroot = &rootcxt.sysroot;
     let mut state = SavedState::load_from_disk("/")?.unwrap_or_default();
     let component = component::new_from_name(name)?;
@@ -278,10 +281,15 @@ pub(crate) fn adopt_and_update(name: &str, rootcxt: &RootContext) -> Result<Cont
     let inst = component
         .adopt_update(&rootcxt, &update)
         .context("Failed adopt and update")?;
-    state.installed.insert(component.name().into(), inst);
-
-    state_guard.update_state(&state)?;
-    Ok(update)
+    if let Some(inst) = inst {
+        state.installed.insert(component.name().into(), inst);
+        state_guard.update_state(&state)?;
+        return Ok(Some(update));
+    } else {
+        // Nothing adopted, skip
+        log::info!("Component '{}' skipped adoption", component.name());
+        return Ok(None);
+    }
 }
 
 /// daemon implementation of component validate
@@ -492,9 +500,10 @@ pub(crate) fn client_run_update() -> Result<()> {
     }
     for (name, adoptable) in status.adoptable.iter() {
         if adoptable.confident {
-            let r: ContentMetadata = adopt_and_update(name, &rootcxt)?;
-            println!("Adopted and updated: {}: {}", name, r.version);
-            updated = true;
+            if let Some(r) = adopt_and_update(name, &rootcxt)? {
+                println!("Adopted and updated: {}: {}", name, r.version);
+                updated = true;
+            }
         } else {
             println!("Component {} requires explicit adopt-and-update", name);
         }
@@ -512,8 +521,9 @@ pub(crate) fn client_run_adopt_and_update() -> Result<()> {
         println!("No components are adoptable.");
     } else {
         for (name, _) in status.adoptable.iter() {
-            let r: ContentMetadata = adopt_and_update(name, &rootcxt)?;
-            println!("Adopted and updated: {}: {}", name, r.version);
+            if let Some(r) = adopt_and_update(name, &rootcxt)? {
+                println!("Adopted and updated: {}: {}", name, r.version);
+            }
         }
     }
     Ok(())

src/component.rs

@@ -36,7 +36,7 @@ pub(crate) trait Component {
         &self,
         rootcxt: &RootContext,
         update: &ContentMetadata,
-    ) -> Result<InstalledContent>;
+    ) -> Result<Option<InstalledContent>>;
 
     /// Implementation of `bootupd install` for a given component.  This should
     /// gather data (or run binaries) from the source root, and install them

src/efi.rs

@@ -250,10 +250,10 @@ impl Component for Efi {
         &self,
         rootcxt: &RootContext,
         updatemeta: &ContentMetadata,
-    ) -> Result<InstalledContent> {
+    ) -> Result<Option<InstalledContent>> {
         let esp_devices = blockdev::find_colocated_esps(&rootcxt.devices)?;
         let Some(meta) = self.query_adopt(&esp_devices)? else {
-            anyhow::bail!("Failed to find adoptable system")
+            return Ok(None);
         };
 
         let esp_devices = esp_devices.unwrap_or_default();
@@ -282,11 +282,11 @@ impl Component for Efi {
         log::trace!("applying adoption diff: {}", &diff);
         filetree::apply_diff(&updated, &destdir, &diff, None)
             .context("applying filesystem changes")?;
-        Ok(InstalledContent {
+        Ok(Some(InstalledContent {
             meta: updatemeta.clone(),
             filetree: Some(updatef),
             adopted_from: Some(meta.version),
-        })
+        }))
     }
 
     fn install(