install: Use zipl to install bootloader on s390x

Running zipl via ostree does not work correctly on a loop deivce.
This patch changes bootc to execute zipl directly with appropriate
command line options for installation on a loop device.

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>

lib/src/bootloader.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{anyhow, bail, Context, Result};
 use camino::Utf8Path;
 use fn_error_context::context;
 
@@ -28,3 +28,80 @@ pub(crate) fn install_via_bootupd(
  .verbose()
  .run()
 }
+
+#[context("Installing bootloader using zipl")]
+pub(crate) fn install_via_zipl(device: &PartitionTable, boot_uuid: &str) -> Result<()> {
+ // Identify the target boot partition from UUID
+ let fs = crate::mount::inspect_filesystem_by_uuid(boot_uuid)?;
+ let boot_dir = Utf8Path::new(&fs.target);
+ let maj_min = fs.maj_min;
+
+ // Ensure that the found partition is a part of the target device
+ let device_path = device.path();
+
+ let partitions = crate::blockdev::list_dev(device_path)?
+ .children
+ .with_context(|| format!("no partition found on {device_path}"))?;
+ let boot_part = partitions
+ .iter()
+ .find(|part| part.maj_min.as_deref() == Some(maj_min.as_str()))
+ .with_context(|| format!("partition device {maj_min} is not on {device_path}"))?;
+ let boot_part_offset = boot_part.start.unwrap_or(0);
+
+ // Find exactly one BLS configuration under /boot/loader/entries
+ // TODO: utilize the BLS parser in ostree
+ let bls_dir = boot_dir.join("boot/loader/entries");
+ let bls_entry = bls_dir
+ .read_dir_utf8()?
+ .try_fold(None, |acc, e| -> Result<_> {
+ let e = e?;
+ let name = Utf8Path::new(e.file_name());
+ if let Some("conf") = name.extension() {
+ if acc.is_some() {
+ bail!("more than one BLS configurations under {bls_dir}");
+ }
+ Ok(Some(e.path().to_owned()))
+ } else {
+ Ok(None)
+ }
+ })?
+ .with_context(|| format!("no BLS configuration under {bls_dir}"))?;
+
+ let bls_path = bls_dir.join(bls_entry);
+ let bls_conf =
+ std::fs::read_to_string(&bls_path).with_context(|| format!("reading {bls_path}"))?;
+
+ let mut kernel = None;
+ let mut initrd = None;
+ let mut options = None;
+
+ for line in bls_conf.lines() {
+ match line.split_once(char::is_whitespace) {
+ Some(("linux", val)) => kernel = Some(val.trim().trim_start_matches('/')),
+ Some(("initrd", val)) => initrd = Some(val.trim().trim_start_matches('/')),
+ Some(("options", val)) => options = Some(val.trim()),
+ _ => (),
+ }
+ }
+
+ let kernel = kernel.ok_or_else(|| anyhow!("missing 'linux' key in default BLS config"))?;
+ let initrd = initrd.ok_or_else(|| anyhow!("missing 'initrd' key in default BLS config"))?;
+ let options = options.ok_or_else(|| anyhow!("missing 'options' key in default BLS config"))?;
+
+ let image = boot_dir.join(kernel).canonicalize_utf8()?;
+ let ramdisk = boot_dir.join(initrd).canonicalize_utf8()?;
+
+ // Execute the zipl command to install bootloader
+ let zipl_desc = format!("running zipl to install bootloader on {device_path}");
+ let zipl_task = Task::new(&zipl_desc, "zipl")
+ .args(["--target", boot_dir.as_str()])
+ .args(["--image", image.as_str()])
+ .args(["--ramdisk", ramdisk.as_str()])
+ .args(["--parameters", options])
+ .args(["--targetbase", device_path.as_str()])
+ .args(["--targettype", "SCSI"])
+ .args(["--targetblocksize", "512"])
+ .args(["--targetoffset", &boot_part_offset.to_string()])
+ .args(["--add-files", "--verbose"]);
+ zipl_task.verbose().run().context(zipl_desc)
+}

lib/src/install.rs

@@ -573,15 +573,9 @@ async fn initialize_ostree_root_from_self(
  crate::lsm::ensure_dir_labeled(rootfs_dir, "boot", None, 0o755.into(), sepolicy)?;
  }
 
- // Default to avoiding grub2-mkconfig etc., but we need to use zipl on s390x.
- // TODO: Lower this logic into ostree proper.
- let bootloader = if cfg!(target_arch = "s390x") {
- "zipl"
- } else {
- "none"
- };
  for (k, v) in [
- ("sysroot.bootloader", bootloader),
+ // Default to avoiding grub2-mkconfig etc.
+ ("sysroot.bootloader", "none"),
  // Always flip this one on because we need to support alongside installs
  // to systems without a separate boot partition.
  ("sysroot.bootprefix", "true"),
@@ -1239,12 +1233,17 @@ async fn install_to_filesystem_impl(state: &State, rootfs: &mut RootSetup) -> Re
  })
  .context("Writing aleph version")?;
  }
+ if cfg!(target_arch = "s390x") {
+ // TODO: Integrate s390x support into install_via_bootupd
+ crate::bootloader::install_via_zipl(&rootfs.device_info, boot_uuid)?;
+ } else {
+ crate::bootloader::install_via_bootupd(
+ &rootfs.device_info,
+ &rootfs.rootfs,
+ &state.config_opts,
+ )?;
+ }
 
- crate::bootloader::install_via_bootupd(
- &rootfs.device_info,
- &rootfs.rootfs,
- &state.config_opts,
- )?;
  tracing::debug!("Installed bootloader");
 
  // Finalize mounted filesystems