parsear entrypoint en image config

rootfs/init/src/main.rs

@@ -8,7 +8,8 @@ use std::{env, io, os::unix, path::Path, process};
 #[serde(rename_all = "PascalCase")]
 struct Config {
     env: Vec<String>,
-    cmd: Vec<String>,
+    cmd: Option<Vec<String>>,
+    entrypoint: Option<Vec<String>>,
 }
 
 #[derive(Serialize, Deserialize, Debug)]
@@ -39,8 +40,20 @@ fn main() -> Result<(), io::Error> {
     unix::fs::chroot(src_path)?;
     env::set_current_dir("/")?;
 
-    let mut child = process::Command::new(&config.config.cmd[0])
+    // https://github.com/opencontainers/image-spec/blob/b5ec432b1c946c09e1568b18ef70b654a93739f6/conversion.md#verbatim-fields
-        .args(&config.config.cmd[1..])
+    let args = match (config.config.cmd, config.config.entrypoint) {
+        (None, Some(args)) => args,
+        (Some(args), None) => args,
+        (None, None) => panic!("Invalid config"),
+        (Some(cmd), Some(entrypoint)) => {
+            let mut args = entrypoint.clone();
+            args.append(&mut cmd.clone());
+            args
+        }
+    };
+
+    let mut child = process::Command::new(&args[0])
+        .args(&args[1..])
         .env_clear()
         .envs(config.config.env.iter().map(|s| s.split_once('=').unwrap()))
         .spawn()?;