composefs-oci,composefs-boot: Extend V1 EROFS to OCI and booting

Migrate OCI crate callers to the new RepositoryConfig API and add
dual-format (V1+V2) EROFS image generation during OCI pull.

The V1 kernel cmdline karg uses a new self-describing format:

  composefs.digest=v1-sha256-12:<hex>
  composefs.digest=v1-sha512-12:<hex>

The value encodes the EROFS format version, hash algorithm, and
block size before the digest, mirroring how meta.json uses
fsverity-sha256-12. The stable key name composefs.digest works
naturally with ConditionKernelCommandLine= and allows multiple
entries on the same cmdline for different algorithm/format
combinations.

The initramfs (composefs-setup-root) parses all composefs kargs
from the kernel cmdline in order, then tries to mount each image
in sequence — the first image that actually exists in the
repository wins. mount_composefs_image_if_exists() maps
ImageNotFound to Ok(None), letting the mount loop skip missing
images without swallowing real errors (verity mismatch,
permissions, etc.).

The legacy composefs=<hex> karg continues to work for V2 EROFS.

Assisted-by: OpenCode (Claude Opus 4)
Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

.github/workflows/bootc-revdep.yml

@@ -48,4 +48,4 @@ jobs:
           # Use bootc branch adapted to composefs-rs API changes
           # TODO: revert to main once bootc-dev/bootc merges these adaptations
           COMPOSEFS_BOOTC_REPO: https://github.com/cgwalters/bootc
-          COMPOSEFS_BOOTC_REF: adapt-composefs-rs-api
+          COMPOSEFS_BOOTC_REF: adapt-composefs-rs-v1-erofs-2

crates/composefs-boot/src/bootloader.rs

@@ -19,7 +19,7 @@ use composefs::{
     tree::{DirectoryRef, FileSystem, ImageError, Inode, LeafContent, RegularFile},
 };
 
-use crate::cmdline::{make_cmdline_composefs, split_cmdline};
+use crate::cmdline::split_cmdline;
 
 /// Strips the key (if it matches) plus the following whitespace from a single line in a "Type #1
 /// Boot Loader Specification Entry" file.
@@ -139,11 +139,15 @@ impl BootLoaderEntryFile {
         self.lines.push(format!("options {arg}"));
     }
 
-    /// Adjusts the kernel command-line arguments by adding a composefs= parameter (if appropriate)
-    /// and adding additional arguments, as requested.
-    pub fn adjust_cmdline(&mut self, composefs: Option<&str>, insecure: bool, extra: &[&str]) {
-        if let Some(id) = composefs {
-            self.add_cmdline(&make_cmdline_composefs(id, insecure));
+    /// Adjusts the kernel command-line arguments by adding a composefs karg (if provided)
+    /// and adding additional arguments.
+    ///
+    /// `karg` should be a complete kernel argument string such as
+    /// `"composefs.digest=v1-sha256-12:abc123"` or `"composefs=abc123"` as produced by
+    /// [`composefs_boot::cmdline::ComposefsCmdline::to_cmdline_arg`].
+    pub fn adjust_cmdline(&mut self, karg: Option<&str>, extra: &[&str]) {
+        if let Some(k) = karg {
+            self.add_cmdline(k);
         }
 
         for item in extra {
@@ -776,7 +780,7 @@ mod tests {
     #[test]
     fn test_adjust_cmdline_with_composefs() {
         let mut entry = BootLoaderEntryFile::new("title Test Entry\nlinux /vmlinuz\n");
-        entry.adjust_cmdline(Some("abc123"), false, &["quiet", "splash"]);
+        entry.adjust_cmdline(Some("composefs=abc123"), &["quiet", "splash"]);
 
         assert_eq!(entry.lines.len(), 3);
         assert_eq!(entry.lines[2], "options composefs=abc123 quiet splash");
@@ -785,17 +789,16 @@ mod tests {
     #[test]
     fn test_adjust_cmdline_with_composefs_insecure() {
         let mut entry = BootLoaderEntryFile::new("title Test Entry\nlinux /vmlinuz\n");
-        entry.adjust_cmdline(Some("abc123"), true, &[]);
+        entry.adjust_cmdline(Some("composefs=?abc123"), &[]);
 
         assert_eq!(entry.lines.len(), 3);
-        // Assuming make_cmdline_composefs adds digest=off for insecure mode
-        assert!(entry.lines[2].contains("abc123"));
+        assert_eq!(entry.lines[2], "options composefs=?abc123");
     }
 
     #[test]
     fn test_adjust_cmdline_no_composefs() {
         let mut entry = BootLoaderEntryFile::new("title Test Entry\nlinux /vmlinuz\n");
-        entry.adjust_cmdline(None, false, &["quiet", "splash"]);
+        entry.adjust_cmdline(None, &["quiet", "splash"]);
 
         assert_eq!(entry.lines.len(), 3);
         assert_eq!(entry.lines[2], "options quiet splash");
@@ -804,7 +807,7 @@ mod tests {
     #[test]
     fn test_adjust_cmdline_existing_options() {
         let mut entry = BootLoaderEntryFile::new("title Test Entry\noptions root=/dev/sda1\n");
-        entry.adjust_cmdline(Some("abc123"), false, &["quiet"]);
+        entry.adjust_cmdline(Some("composefs=abc123"), &["quiet"]);
 
         assert_eq!(entry.lines.len(), 2);
         assert!(entry.lines[1].contains("root=/dev/sda1"));