From 95fc6abc8d35c50fd163419e5d3789769f378b4c Mon Sep 17 00:00:00 2001
From: Codex <codex@localhost>
Date: Tue, 13 Oct 2026 05:01:33 +0300
Subject: [PATCH] fix(image): select actual Gentoo distribution kernel image

---
 hydra/build.py      |  2 +-
 hydra/image.py      | 23 +++++++++++++++++++----
 tests/test_image.py | 13 +++++++++++++
 3 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/hydra/build.py b/hydra/build.py
index 62af262..4440554 100644
--- a/hydra/build.py
+++ b/hydra/build.py
@@ -430,7 +430,7 @@ mkdir -p "$root"
 touch "$root/.hydra-export-owned"
 tar --extract --preserve-permissions --numeric-owner --file /hydra-output/artifacts/builder-rootfs.tar --directory "$root"
 /hydra-source/image/configure-rootfs.sh "$root"
-cp "$root/boot/vmlinuz-$(python3 /hydra-source/hydra/image.py kernel "$root")" /hydra-output/artifacts/vmlinuz
+cp "$(python3 /hydra-source/hydra/image.py kernel-image "$root")" /hydra-output/artifacts/vmlinuz
 cp "$root/boot/initramfs-live.img" /hydra-output/artifacts/initramfs-live.img
 cp "$root/usr/share/hydra/build-manifest.json" /hydra-output/artifacts/rootfs-manifest.json
 # Keep ownership for safe retries outside the shipped payload.
diff --git a/hydra/image.py b/hydra/image.py
index 1ca571c..9d7eebe 100644
--- a/hydra/image.py
+++ b/hydra/image.py
@@ -129,16 +129,29 @@ def copy_overlay(root, overlay):
             destination.chmod(source.stat().st_mode & 0o777)
 
 
-def kernel_version(root):
+def _kernel_version(root):
     modules = root_path(root, 'lib/modules')
     versions = sorted(path.name for path in modules.iterdir() if path.is_dir()) if modules.is_dir() else []
     if len(versions) != 1 or not re.fullmatch(r'[A-Za-z0-9_.+-]+', versions[0]):
         raise ImageError('Exactly one installed payload kernel is required')
-    if not root_path(root, 'boot/vmlinuz-' + versions[0]).is_file():
-        raise ImageError('Installed modules have no matching /boot/vmlinuz-VERSION')
     return versions[0]
 
 
+def kernel_image(root):
+    version = _kernel_version(root)
+    candidates = [root_path(root, 'boot/' + prefix + version)
+                  for prefix in ('kernel-', 'vmlinuz-')]
+    images = [path for path in candidates if path.is_file()]
+    if len(images) != 1:
+        raise ImageError('Installed modules require exactly one matching boot kernel image')
+    return images[0]
+
+
+def kernel_version(root):
+    kernel_image(root)
+    return _kernel_version(root)
+
+
 def live_kernel_args():
     return [f'root=live:CDLABEL={LABEL}', 'rd.live.image', 'rd.live.overlay.overlayfs=1',
             'ro', 'console=tty0', 'console=ttyS0,115200n8']
@@ -356,7 +369,7 @@ def digest(path):
 
 def main(argv=None):
     parser = argparse.ArgumentParser(description=__doc__)
-    parser.add_argument('step', choices=('configure', 'kernel', 'network', 'audio'))
+    parser.add_argument('step', choices=('configure', 'kernel', 'kernel-image', 'network', 'audio'))
     parser.add_argument('root', nargs='?', type=Path)
     parser.add_argument('--source', type=Path)
     options = parser.parse_args(argv)
@@ -367,6 +380,8 @@ def main(argv=None):
             raise ImageError('An isolated rootfs directory is required')
         if options.step == 'kernel':
             print(kernel_version(options.root))
+        elif options.step == 'kernel-image':
+            print(kernel_image(options.root))
         elif options.step == 'audio':
             enable_user_audio(options.root)
         else:
diff --git a/tests/test_image.py b/tests/test_image.py
index 55c0487..7aade23 100644
--- a/tests/test_image.py
+++ b/tests/test_image.py
@@ -39,6 +39,19 @@ class ImageTests(unittest.TestCase):
         self.kernel()
         self.assertEqual(image.kernel_version(self.root), '6.12.58-gentoo-dist')
 
+    def test_real_gentoo_kernel_bin_layout(self):
+        version = '6.18.54-gentoo-dist-bin'
+        (self.root / 'lib/modules' / version).mkdir(parents=True)
+        kernel = self.file('boot/kernel-' + version, 'real Gentoo kernel')
+        self.assertEqual(image.kernel_version(self.root), version)
+        self.assertEqual(image.kernel_image(self.root), kernel)
+
+    def test_conflicting_kernel_images_refused(self):
+        version = self.kernel()
+        self.file('boot/kernel-' + version, 'different kernel')
+        with self.assertRaises(image.ImageError):
+            image.kernel_version(self.root)
+
     def test_ambiguous_or_missing_kernel_refused(self):
         with self.assertRaises(image.ImageError):
             image.kernel_version(self.root)