hypha: implement the ability to override the command line to execute

hypha/src/ctl/cfgblk.rs

@@ -1,5 +1,6 @@
 use crate::error::Result;
 use crate::image::ImageInfo;
+use crate::shared::LaunchInfo;
 use backhand::{FilesystemWriter, NodeHeader};
 use std::fs;
 use std::fs::File;
@@ -32,12 +33,13 @@ impl ConfigBlock<'_> {
         })
     }
 
-    pub fn build(&self) -> Result<()> {
+    pub fn build(&self, launch_config: &LaunchInfo) -> Result<()> {
         let config_bundle_content = match self.config_bundle {
             None => None,
             Some(path) => Some(fs::read(path)?),
         };
         let manifest = self.image_info.config.to_string()?;
+        let launch = serde_json::to_string(launch_config)?;
         let mut writer = FilesystemWriter::default();
         writer.push_dir(
             "/image",
@@ -58,6 +60,16 @@ impl ConfigBlock<'_> {
                 mtime: 0,
             },
         )?;
+        writer.push_file(
+            launch.as_bytes(),
+            "/launch.json",
+            NodeHeader {
+                permissions: 384,
+                uid: 0,
+                gid: 0,
+                mtime: 0,
+            },
+        )?;
         if let Some(config_bundle_content) = config_bundle_content.as_ref() {
             writer.push_file(
                 config_bundle_content.as_slice(),

hypha/src/ctl/mod.rs

@@ -6,6 +6,7 @@ use crate::error::{HyphaError, Result};
 use crate::image::cache::ImageCache;
 use crate::image::name::ImageName;
 use crate::image::{ImageCompiler, ImageInfo};
+use crate::shared::LaunchInfo;
 use loopdev::LoopControl;
 use std::io::{Read, Write};
 use std::path::PathBuf;
@@ -59,6 +60,7 @@ impl Controller {
         compiler.compile(&image)
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub fn launch(
         &mut self,
         kernel_path: &str,
@@ -67,12 +69,15 @@ impl Controller {
         image: &str,
         vcpus: u32,
         mem: u64,
+        run: Option<Vec<String>>,
     ) -> Result<u32> {
         let uuid = Uuid::new_v4();
         let name = format!("hypha-{uuid}");
         let image_info = self.compile(image)?;
+        let launch_config = LaunchInfo { run };
+
         let cfgblk = ConfigBlock::new(&uuid, &image_info, config_bundle_path)?;
-        cfgblk.build()?;
+        cfgblk.build(&launch_config)?;
 
         let image_squashfs_path = image_info
             .image_squashfs