feat: Doing the swap

appmgr/src/update/mod.rs

@@ -1,7 +1,9 @@
-use anyhow::anyhow;
+use anyhow::{anyhow, bail, Result};
 use clap::ArgMatches;
 use digest::Digest;
 use futures::Stream;
+use lazy_static::lazy_static;
+use regex::Regex;
 use rpc_toolkit::command;
 use serde_json::Value;
 use sha2::Sha256;
@@ -13,22 +15,98 @@ use crate::context::RpcContext;
 use crate::update::latest_information::LatestInformation;
 use crate::{Error, ErrorKind, ResultExt};
 
+/// An user/ daemon would call this to update the system to the latest version and do the updates available,
+/// and this will return something if there is an update, and in that case there will need to be a restart.
+#[command(display(display_properties))]
+pub async fn update_system(#[context] ctx: RpcContext) -> Result<UpdateSystem, Error> {
+    if let None = maybe_do_update(ctx).await? {
+        return Ok(UpdateSystem::Updated);
+    }
+    Ok(UpdateSystem::NoUpdates)
+}
+
+/// What is the status of the updates?
+#[derive(serde::Serialize, serde::Deserialize, Clone, Debug)]
+pub enum UpdateSystem {
+    NoUpdates,
+    Updated,
+}
+
+fn display_properties(status: UpdateSystem, _: &ArgMatches<'_>) {
+    match status {
+        UpdateSystem::NoUpdates => {
+            println!("Updates are ready, please reboot");
+        }
+        UpdateSystem::Updated => {
+            println!("No updates needed");
+        }
+    }
+}
+
 const URL: &str = "https://beta-registry-0-3.start9labs.com/eos/latest";
 const HEADER_KEY: &str = "CHECKSUM";
 mod latest_information;
 
-pub fn display_properties(_: (), _: &ArgMatches<'_>) {
-    println!("Test");
-}
-#[command(display(display_properties))]
-pub async fn update_system(#[context] ctx: RpcContext) -> Result<(), Error> {
-    if let None = maybe_do_update(ctx).await? {
-        return Ok(());
-    }
-    todo!()
+enum WritableDrives {
+    Green,
+    Blue,
 }
 
-pub async fn maybe_do_update(mut ctx: RpcContext) -> Result<Option<()>, Error> {
+struct Boot;
+
+/// We are going to be creating some folders and mounting so
+/// we need to know the labels for those types. These labels
+/// are the labels that are shipping with the embassy, blue/ green
+/// are where the os sits and will do a swap during update.
+trait FileType {
+    fn mount_folder(&self) -> String {
+        format!("/media/{}", self.label())
+    }
+    fn label(&self) -> String;
+}
+impl FileType for WritableDrives {
+    fn label(&self) -> String {
+        match self {
+            WritableDrives::Green => "green",
+            WritableDrives::Blue => "blue",
+        }
+        .to_string()
+    }
+}
+impl FileType for Boot {
+    fn label(&self) -> String {
+        "system-boot".to_string()
+    }
+}
+
+/// Proven data that this is mounted, should be consumed in an unmount
+struct MountedResource<X: FileType>(X);
+impl<X: FileType> MountedResource<X> {
+    async fn unmount_label(&self) -> Result<()> {
+        let folder = self.0.mount_folder();
+        tokio::process::Command::new("umount")
+            .arg(&folder)
+            .output()
+            .await?;
+        tokio::process::Command::new("rmdir")
+            .arg(folder)
+            .output()
+            .await?;
+        Ok(())
+    }
+}
+
+/// This will be where we are going to be putting the new update
+struct NewLabel<'a>(&'a MountedResource<WritableDrives>);
+
+/// This is our current label where the os is running
+struct CurrentLabel<'a>(&'a MountedResource<WritableDrives>);
+
+lazy_static! {
+    static ref PARSE_COLOR: Regex = Regex::new("#LABEL=(\\w+) /media/root-ro/").unwrap();
+}
+
+async fn maybe_do_update(mut ctx: RpcContext) -> Result<Option<()>, Error> {
     let mut db = ctx.db.handle();
     let latest_version = reqwest::get(URL)
         .await
@@ -42,17 +120,72 @@ pub async fn maybe_do_update(mut ctx: RpcContext) -> Result<Option<()>, Error> {
         .version()
         .get_mut(&mut db)
         .await?;
-    if &latest_version > &current_version {
-        let file_name = "/tmp/test";
-        download_file(file_name).await?;
-        swap(&mut ctx).await?;
-        Ok(Some(()))
-    } else {
-        Ok(None)
+    if &latest_version <= &current_version {
+        return Ok(None);
+    }
+    let file_name = "/tmp/test";
+    let mounted_blue = mount_label(WritableDrives::Blue)
+        .await
+        .with_kind(ErrorKind::Filesystem)?;
+    let mounted_green = mount_label(WritableDrives::Green)
+        .await
+        .with_kind(ErrorKind::Filesystem)?;
+    let mounted_boot = mount_label(Boot).await.with_kind(ErrorKind::Filesystem)?;
+    let potential_error_actions = async {
+        let (new_label, _current_label) = query_mounted_label(&mounted_blue, &mounted_green)
+            .await
+            .with_kind(ErrorKind::Filesystem)?;
+        download_file(file_name, &new_label).await?;
+
+        swap_boot_label(&mut ctx, &new_label, &mounted_boot).await?;
+        Ok::<_, Error>(())
+    }
+    .await;
+
+    mounted_blue
+        .unmount_label()
+        .await
+        .with_kind(ErrorKind::Filesystem)?;
+    mounted_green
+        .unmount_label()
+        .await
+        .with_kind(ErrorKind::Filesystem)?;
+    mounted_boot
+        .unmount_label()
+        .await
+        .with_kind(ErrorKind::Filesystem)?;
+    potential_error_actions?;
+    Ok(Some(()))
+}
+
+async fn query_mounted_label<'a>(
+    mounted_resource_left: &'a MountedResource<WritableDrives>,
+    mounted_resource_right: &'a MountedResource<WritableDrives>,
+) -> Result<(NewLabel<'a>, CurrentLabel<'a>)> {
+    let output = String::from_utf8(
+        tokio::process::Command::new("cat")
+            .arg("/etc/fstab")
+            .output()
+            .await?
+            .stdout,
+    )?;
+    match &PARSE_COLOR
+        .captures(&output)
+        .ok_or_else(|| anyhow!("Can't find pattern in {}", output))?[1]
+    {
+        x if x == &mounted_resource_left.0.label() => Ok((
+            NewLabel(mounted_resource_left),
+            CurrentLabel(mounted_resource_right),
+        )),
+        x if x == &mounted_resource_right.0.label() => Ok((
+            NewLabel(mounted_resource_right),
+            CurrentLabel(mounted_resource_left),
+        )),
+        e => bail!("Could not find a mounted resource for {}", e),
     }
 }
 
-pub async fn download_file(file_name: &str) -> Result<(), Error> {
+async fn download_file(file_name: &str, new_label: &NewLabel<'_>) -> Result<(), Error> {
     let download_request = reqwest::get(URL).await.with_kind(ErrorKind::Network)?;
     let hash_from_header: String = download_request
         .headers()
@@ -83,7 +216,7 @@ async fn write_stream_to_file(
     Ok(hasher.finalize().to_vec())
 }
 
-pub async fn check_download(hash_from_header: &str, file_digest: Vec<u8>) -> Result<(), Error> {
+async fn check_download(hash_from_header: &str, file_digest: Vec<u8>) -> Result<(), Error> {
     if hex::decode(hash_from_header).with_kind(ErrorKind::Network)? != file_digest {
         return Err(Error::new(
             anyhow!("Hash sum does not match source"),
@@ -92,9 +225,54 @@ pub async fn check_download(hash_from_header: &str, file_digest: Vec<u8>) -> Res
     }
     Ok(())
 }
-
-pub async fn swap(ctx: &mut RpcContext) -> Result<Value, Error> {
+async fn swap_boot_label(
+    ctx: &mut RpcContext,
+    new_label: &NewLabel<'_>,
+    mounted_boot: &MountedResource<Boot>,
+) -> Result<(), Error> {
     // disk/util add setLabel
-    todo!("Do swap");
-    todo!("Let system know that we need a reboot or something")
+    tokio::process::Command::new("sed")
+        .arg(format!(r#""r/(blue|green)/{}/g""#, new_label.0 .0.label()))
+        .arg(format!("{}/etc/fstab", mounted_boot.0.mount_folder()))
+        .output()
+        .await?;
+    Ok(())
+}
+
+async fn mount_label<F>(file_type: F) -> Result<MountedResource<F>>
+where
+    F: FileType,
+{
+    let label = file_type.label();
+    let folder = file_type.mount_folder();
+    tokio::process::Command::new("mdkir")
+        .arg(&folder)
+        .output()
+        .await?;
+    tokio::process::Command::new("mount")
+        .arg("-L")
+        .arg(label)
+        .arg(folder)
+        .output()
+        .await?;
+    Ok(MountedResource(file_type))
+}
+/// Captured from doing an fstab with an embassy box and the cat from the /etc/fstab
+#[test]
+fn test_capture() {
+    let output = r#"
+#
+#  This fstab is for overlayroot. The real one can be found at
+#  /media/root-ro/etc/fstab
+#  The original entry for '/' and other mounts have been updated to be placed
+#  under /media/root-ro.
+#  To permanently modify this (or any other file), you should change-root into
+#  a writable view of the underlying filesystem using:
+#      sudo overlayroot-chroot
+#
+#LABEL=blue /media/root-ro/ ext4 ro,discard,errors=remount-ro,noauto 0 1
+/media/root-ro/ / overlay lowerdir=/media/root-ro/,upperdir=/media/root-rw/overlay/,workdir=/media/root-rw/overlay-workdir/_ 0 1
+LABEL=system-boot /boot/firmware vfat defaults 0 1 # overlayroot:fs-unsupported
+"#;
+    assert_eq!(&PARSE_COLOR.captures(&output).unwrap()[1], "blue");
 }