[pve-devel] [PATCH installer v2 3/5] fix #5579: auto-install-assistant: enable baking in first-boot script

[Christoph Heiss]

Adds a new parameter `--on-first-boot` to the `prepare-iso` command, to
specify a file to bake into the ISO.

To later use it with the auto-installer, the following must be set in
the answer file:

  [first-boot]
  source = "from-iso"

Signed-off-by: Christoph Heiss <c.heiss at proxmox.com>
---
Changes v1 -> v2:
  * add filesize check; only allow up to 1 MiB scripts

 proxmox-auto-install-assistant/Cargo.toml  |  1 +
 proxmox-auto-install-assistant/src/main.rs | 30 +++++++++++++++++++++-
 proxmox-installer-common/src/lib.rs        |  6 +++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/proxmox-auto-install-assistant/Cargo.toml b/proxmox-auto-install-assistant/Cargo.toml
index c4486f8..07e6ffb 100644
--- a/proxmox-auto-install-assistant/Cargo.toml
+++ b/proxmox-auto-install-assistant/Cargo.toml
@@ -13,6 +13,7 @@ homepage = "https://www.proxmox.com"
 [dependencies]
 anyhow.workspace = true
 log.workspace = true
+proxmox-installer-common.workspace = true
 proxmox-auto-installer.workspace = true
 serde = { workspace = true, features = ["derive"] }
 serde_json.workspace = true
diff --git a/proxmox-auto-install-assistant/src/main.rs b/proxmox-auto-install-assistant/src/main.rs
index bdcf067..d7aa134 100644
--- a/proxmox-auto-install-assistant/src/main.rs
+++ b/proxmox-auto-install-assistant/src/main.rs
@@ -19,6 +19,7 @@ use proxmox_auto_installer::{
         FetchAnswerFrom, HttpOptions,
     },
 };
+use proxmox_installer_common::{FIRST_BOOT_EXEC_MAX_SIZE, FIRST_BOOT_EXEC_NAME};
 
 static PROXMOX_ISO_FLAG: &str = "/auto-installer-capable";
 
@@ -149,6 +150,13 @@ struct CommandPrepareISO {
     // so shorten "Automated Installer Source" to "AIS" to be safe.
     #[arg(long, default_value_t = { "proxmox-ais".to_owned() } )]
     partition_label: String,
+
+    /// Executable file to include, which should be run on the first system boot after the
+    /// installation. Can be used for further bootstrapping the new system.
+    ///
+    /// Must be appropriately enabled in the answer file.
+    #[arg(long)]
+    on_first_boot: Option<PathBuf>,
 }
 
 /// Show the system information that can be used to identify a host.
@@ -201,7 +209,7 @@ fn main() {
         Commands::SystemInfo(args) => show_system_info(args),
     };
     if let Err(err) = res {
-        eprintln!("{err}");
+        eprintln!("Error: {err:?}");
         std::process::exit(1);
     }
 }
@@ -305,6 +313,17 @@ fn prepare_iso(args: &CommandPrepareISO) -> Result<()> {
         bail!("You must set '--fetch-from' to 'iso' to place the answer file directly in the ISO.");
     }
 
+    if let Some(first_boot) = &args.on_first_boot {
+        let metadata = fs::metadata(first_boot)?;
+
+        if metadata.len() > FIRST_BOOT_EXEC_MAX_SIZE.try_into()? {
+            bail!(
+                "Maximum file size for first-boot executable file is {} MiB",
+                FIRST_BOOT_EXEC_MAX_SIZE / 1024 / 1024
+            )
+        }
+    }
+
     if let Some(file) = &args.answer_file {
         println!("Checking provided answer file...");
         parse_answer(file)?;
@@ -352,6 +371,15 @@ fn prepare_iso(args: &CommandPrepareISO) -> Result<()> {
         inject_file_to_iso(&tmp_iso, answer_file, "/answer.toml", &uuid)?;
     }
 
+    if let Some(first_boot) = &args.on_first_boot {
+        inject_file_to_iso(
+            &tmp_iso,
+            first_boot,
+            &format!("/{FIRST_BOOT_EXEC_NAME}"),
+            &uuid,
+        )?;
+    }
+
     println!("Moving prepared ISO to target location...");
     fs::rename(&tmp_iso, &iso_target)?;
     println!("Final ISO is available at {iso_target:?}.");
diff --git a/proxmox-installer-common/src/lib.rs b/proxmox-installer-common/src/lib.rs
index 10b5940..13acb89 100644
--- a/proxmox-installer-common/src/lib.rs
+++ b/proxmox-installer-common/src/lib.rs
@@ -11,3 +11,9 @@ pub const RUNTIME_DIR: &str = "/run/proxmox-installer";
 
 /// Default placeholder value for the administrator email address.
 pub const EMAIL_DEFAULT_PLACEHOLDER: &str = "mail at example.invalid";
+
+/// Name of the executable for the first-boot hook.
+pub const FIRST_BOOT_EXEC_NAME: &str = "proxmox-first-boot";
+
+/// Maximum file size for the first-boot hook executable.
+pub const FIRST_BOOT_EXEC_MAX_SIZE: usize = 1024 * 1024; // 1 MiB
-- 
2.47.0