auto-create inittab entries for serial consoles

src/cmd/init/bootstrap.rs

@@ -79,7 +79,30 @@ pub async fn bootstrap(cfg: Config) {
     })
     .await;
 
-    exec("chroot", &["/system", "update-ca-certificates"]).await
+    exec("chroot", &["/system", "update-ca-certificates"]).await;
+
+    // activate ttyS* consoles as needed
+    retry_or_ignore(async || {
+        const PATH: &str = "/system/etc/inittab";
+        let mut inittab = fs::read_to_string(PATH).await?;
+        let mut changed = false;
+        for opt in utils::cmdline().filter_map(|s| s.strip_prefix("console=ttyS")) {
+            info!("inittab: adding entry for ttyS{opt}");
+            changed = true;
+
+            let mut params = opt.split(',');
+            let num = params.next().unwrap();
+            let speed = params.next().unwrap_or("115200");
+            inittab.push_str(&format!(
+                "S{num}:12345:respawn:/sbin/agetty --noclear {speed} ttyS{num} linux\n"
+            ));
+        }
+        if changed {
+            fs::write(PATH, inittab.as_bytes()).await?;
+        }
+        Ok(())
+    })
+    .await;
 }
 
 struct Verifier {

src/utils.rs

@@ -11,7 +11,7 @@ static CMDLINE: LazyLock<String> = LazyLock::new(|| {
         .unwrap_or_default()
 });
 
-fn cmdline() -> impl Iterator<Item = &'static str> {
+pub fn cmdline() -> impl Iterator<Item = &'static str> {
     CMDLINE.split_ascii_whitespace()
 }
 

test-initrd/config.yaml

@@ -95,8 +95,8 @@ lvm:
 #- dev: /dev/storage/bootstrap
 #- dev: /dev/storage/dls
 
-signer_public_key: 'MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQBe6Y3zGQUIHvVXoS5GI8irY8yoB0ozFpzn/cUykA46TkHdJ8xCEaaM1MpqMrfWgDtP/rA2KeE9HjVerLnEFD01uUAUh4/OYgCBDYJPhridVDoC78KOJpkWBj7Shl0Rp0AtETvatNPa1RRe15V7nDF/Nm75Y6O3IL29lYPQ6jqEGhR810='
+signer_public_key: 'MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQAd5sR4NqLtjSt8ESNlYWvuufYj7v+aYGDlgxQThcKbzDPVe639IfH94hHE0l9TAfyU94qtN/GpFyKJ68F/u2pu70A/umT1m24ELFDqXlQXqhTsH91r+nYUZ7due3EqSrvru/yjchNNRkpoCCu3QkDF25KnrYfWWHqj9ZIRlBTCJE9SwM='
 bootstrap:
   dev: /dev/storage/bootstrap
-  seed: https://192.168.12.254:7606/public/download-set/host/m1/bootstrap.tar?set=IDZTK4AUNCYCTKF3GIEGSNZF3I7XCINCTJSOWL2JPHCJ2IAZWDECY2XCGQ5MCTJBNFIKBNCLIA3PJSN7IOH7URGXYRYZRCGF4VSW4RIAAQRE2GDEOC4RWAAAQA3DSZJZMU4TGOL4NA5G2MJ2MJXW65DTORZGC4BOORQXEAAAAAADJMFLUE
+  seed: http://192.168.12.254:7606/public/download-set/host/m1/bootstrap.tar?set=ICM5KUZDRAMJPMO5OWW6PSIFYF4AHMYLAQSBZVFUDNG4DQDEW6UFQQJQKMGIXPI4CFOZFVA4CXULRXCAHKX3WELVAYS246FM6SGSGHIOAQRE2GDEOC4RUAAAQA3GEZDFMUZDOMD4NA5CUOTCN5XXI43UOJQXALTUMFZAAAAAACHHUMRU