Merge current main and make purchase filing atomic under concurrent writes

Every paid download logged "filing into filebrowser/Music/... failed
(non-fatal): Permission denied". The purchase played in-app but never
appeared in Files. FileBrowser's folders belong to its rootless container
range (host uid 100000, mode 755). This service is host uid 1000, outside
that range, so it can read them but not create files in them.

New container::filebrowser::save_new_file:
- Writes directly when the folder allows it.
- Otherwise writes through `podman unshare`, where that uid range is
  ours: to a temp file, then chowned to the folder's owner, set to 0644,
  and hard-linked into place. FileBrowser never sees a partial file and an
  existing file is never replaced. A missing folder is created and given
  its parent's owner. No sudo.
- Keeps the "name (2).ext" de-duplication the RPC did inline.

Checked the unshare script on amishparadise in a scratch folder owned
like FileBrowser's: new folder + file OK, owner/mode right, no clobber,
no temp file left, and the service can read the result.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/archipelago/src/api/rpc/content.rs

@@ -54,13 +54,9 @@ fn paid_content_response(bytes: &[u8], mime: &str, paid_sats: u64) -> serde_json
     })
 }
 
-/// FileBrowser owns its files through a rootless UID mapping. Use its authenticated
-/// API rather than writing host paths with the backend's unrelated UID. Its
-/// override=false upload atomically refuses existing names, including races.
+/// File purchases through an atomic no-clobber write in Files' own namespace.
 async fn file_purchase_in_files(
-    client: &reqwest::Client,
-    base_url: &str,
-    token: &str,
+    data_dir: &std::path::Path,
     filename: &str,
     mime: &str,
     bytes: &[u8],
@@ -72,59 +68,24 @@ async fn file_purchase_in_files(
     } else {
         "Documents"
     };
-    let mut folder_url = reqwest::Url::parse(base_url)?;
-    folder_url
-        .path_segments_mut()
-        .map_err(|_| anyhow::anyhow!("Invalid Files URL"))?
-        .extend(["api", "resources", folder, ""]);
-    let response = client
-        .get(folder_url.clone())
-        .header("X-Auth", token)
-        .send()
-        .await?;
-    if response.status() == reqwest::StatusCode::NOT_FOUND {
-        let response = client
-            .post(folder_url.clone())
-            .header("X-Auth", token)
-            .send()
-            .await?;
-        if response.status() != reqwest::StatusCode::CONFLICT {
-            response.error_for_status()?;
-        }
-    } else {
-        response.error_for_status()?;
-    }
-    let base = std::path::Path::new(filename)
+    let root = data_dir.join("filebrowser");
+    anyhow::ensure!(
+        tokio::fs::metadata(&root).await?.is_dir(),
+        "Files storage is unavailable"
+    );
+    let name = std::path::Path::new(filename)
         .file_name()
         .and_then(|n| n.to_str())
         .filter(|n| !n.is_empty())
         .unwrap_or("download");
-    let (stem, extension) = match base.rsplit_once('.') {
-        Some((stem, ext)) if !stem.is_empty() => (stem, format!(".{ext}")),
-        _ => (base, String::new()),
-    };
-    for attempt in 1..=100 {
-        let name = if attempt == 1 {
-            base.to_string()
-        } else {
-            format!("{stem} ({attempt}){extension}")
-        };
-        let mut url = folder_url.clone();
-        url.path_segments_mut().unwrap().pop_if_empty().push(&name);
-        url.query_pairs_mut().append_pair("override", "false");
-        let response = client
-            .post(url)
-            .header("X-Auth", token)
-            .body(bytes.to_vec())
-            .send()
-            .await?;
-        if response.status() == reqwest::StatusCode::CONFLICT {
-            continue;
-        }
-        response.error_for_status()?;
-        return Ok(format!("{folder}/{name}"));
-    }
-    anyhow::bail!("Too many existing copies; purchased file remains in the purchase cache")
+    let path =
+        crate::container::filebrowser::save_new_file(&root.join(folder), name, bytes).await?;
+    Ok(format!(
+        "{folder}/{}",
+        path.file_name()
+            .and_then(|n| n.to_str())
+            .context("Invalid Files name")?
+    ))
 }
 
 impl RpcHandler {
@@ -728,28 +689,8 @@ impl RpcHandler {
 
         // The durable purchased-content cache above is primary. A Files copy
         // remains optional: a stopped FileBrowser must not undo a paid download.
-        let filed = async {
-            let auth = self.handle_filebrowser_token().await?;
-            let token = auth
-                .get("token")
-                .and_then(|v| v.as_str())
-                .context("FileBrowser omitted its authentication token")?;
-            let client = reqwest::Client::builder()
-                .no_proxy()
-                .redirect(reqwest::redirect::Policy::none())
-                .timeout(std::time::Duration::from_secs(30))
-                .build()?;
-            file_purchase_in_files(
-                &client,
-                "http://127.0.0.1:8083",
-                token,
-                &filename,
-                &mime_type,
-                &bytes,
-            )
-            .await
-        }
-        .await;
+        let filed =
+            file_purchase_in_files(&self.config.data_dir, &filename, &mime_type, &bytes).await;
         match filed {
             Ok(path) => tracing::info!("paid download: filed into Files/{path}"),
             Err(error) => tracing::warn!(

core/archipelago/src/api/rpc/content_tests.rs

@@ -1,69 +1,4 @@
 use super::*;
-use hyper::{
-    service::{make_service_fn, service_fn},
-    Body, Response, Server,
-};
-use std::{
-    collections::VecDeque,
-    convert::Infallible,
-    sync::{Arc, Mutex},
-};
-
-struct FilesApi {
-    url: String,
-    seen: Arc<Mutex<Vec<(String, String, Vec<u8>)>>>,
-    task: tokio::task::JoinHandle<()>,
-}
-impl Drop for FilesApi {
-    fn drop(&mut self) {
-        self.task.abort();
-    }
-}
-fn files_api(statuses: Vec<u16>) -> FilesApi {
-    let statuses = Arc::new(Mutex::new(VecDeque::from(statuses)));
-    let seen = Arc::new(Mutex::new(Vec::new()));
-    let history = seen.clone();
-    let server = Server::bind(&([127, 0, 0, 1], 0).into());
-    let address = server.local_addr();
-    let service = make_service_fn(move |_| {
-        let statuses = statuses.clone();
-        let seen = history.clone();
-        async move {
-            Ok::<_, Infallible>(service_fn(move |request: hyper::Request<Body>| {
-                let statuses = statuses.clone();
-                let seen = seen.clone();
-                async move {
-                    assert_eq!(request.headers().get("X-Auth").unwrap(), "test-session");
-                    let method = request.method().to_string();
-                    let uri = request.uri().to_string();
-                    let body = hyper::body::to_bytes(request.into_body())
-                        .await
-                        .unwrap()
-                        .to_vec();
-                    seen.lock().unwrap().push((method, uri, body));
-                    let status = statuses
-                        .lock()
-                        .unwrap()
-                        .pop_front()
-                        .expect("unexpected extra Files request");
-                    Ok::<_, Infallible>(
-                        Response::builder()
-                            .status(status)
-                            .body(Body::empty())
-                            .unwrap(),
-                    )
-                }
-            }))
-        }
-    });
-    FilesApi {
-        url: format!("http://{address}"),
-        seen,
-        task: tokio::spawn(async move {
-            server.serve(service).await.unwrap();
-        }),
-    }
-}
 
 #[test]
 fn first_and_cached_paid_downloads_have_the_same_client_payload_contract() {
@@ -85,80 +20,37 @@ fn first_and_cached_paid_downloads_have_the_same_client_payload_contract() {
 }
 
 #[tokio::test]
-async fn files_copy_uses_authenticated_api_and_preserves_existing_names() {
-    let api = files_api(vec![200, 409, 200]);
-    let client = reqwest::Client::new();
-    let path = file_purchase_in_files(
-        &client,
-        &api.url,
-        "test-session",
-        "../my #file?.txt",
-        "text/plain",
-        b"paid bytes",
-    )
-    .await
-    .unwrap();
-    assert_eq!(path, "Documents/my #file? (2).txt");
-    let seen = api.seen.lock().unwrap();
-    assert_eq!(seen[0].0, "GET");
-    assert_eq!(seen[0].1, "/api/resources/Documents/");
-    assert_eq!(seen.len(), 3);
-    for (_, uri, body) in &seen[1..] {
-        assert!(uri.contains("override=false"));
-        assert!(uri.contains("%23file%3F"));
-        assert!(!uri.contains("../"));
-        assert_eq!(body, b"paid bytes");
-    }
-}
-
-#[tokio::test]
-async fn files_copy_creates_missing_media_folder() {
+async fn files_copy_routes_media_and_sanitizes_the_filename() {
+    let dir = tempfile::tempdir().unwrap();
+    tokio::fs::create_dir(dir.path().join("filebrowser"))
+        .await
+        .unwrap();
     for (mime, folder) in [
         ("image/png", "Photos"),
         ("video/mp4", "Photos"),
-        ("audio/ogg", "Music"),
+        ("audio/mpeg", "Music"),
+        ("text/plain", "Documents"),
     ] {
-        let api = files_api(vec![404, 200, 200]);
-        let path = file_purchase_in_files(
-            &reqwest::Client::new(),
-            &api.url,
-            "test-session",
-            "file",
-            mime,
-            b"bytes",
-        )
-        .await
-        .unwrap();
-        assert_eq!(path, format!("{folder}/file"));
-        let seen = api.seen.lock().unwrap();
-        assert_eq!(seen[1].0, "POST");
-        assert!(seen[1].1.ends_with('/'));
-        assert!(seen[1].2.is_empty());
-        assert_eq!(seen[2].2, b"bytes");
+        let relative = file_purchase_in_files(dir.path(), "../name #?.bin", mime, b"paid")
+            .await
+            .unwrap();
+        assert!(relative.starts_with(&format!("{folder}/name #?")));
+        assert_eq!(
+            tokio::fs::read(dir.path().join("filebrowser").join(relative))
+                .await
+                .unwrap(),
+            b"paid"
+        );
     }
 }
 
 #[tokio::test]
-async fn files_copy_fails_without_overwriting_or_claiming_success_on_errors() {
-    for statuses in [
-        vec![401],
-        vec![503],
-        vec![404, 500],
-        vec![200, 507],
-        vec![200, 403],
-    ] {
-        let expected = statuses.len();
-        let api = files_api(statuses);
-        assert!(file_purchase_in_files(
-            &reqwest::Client::new(),
-            &api.url,
-            "test-session",
-            "file.txt",
-            "text/plain",
-            b"bytes"
-        )
-        .await
-        .is_err());
-        assert_eq!(api.seen.lock().unwrap().len(), expected);
-    }
+async fn unavailable_files_storage_is_reported_without_creating_a_fake_installation() {
+    let dir = tempfile::tempdir().unwrap();
+    assert!(
+        file_purchase_in_files(dir.path(), "name", "text/plain", b"bytes")
+            .await
+            .is_err()
+    );
+    assert!(!dir.path().join("filebrowser").exists());
 }

core/archipelago/src/container/filebrowser.rs

@@ -5,7 +5,7 @@
 //! starting the container with `--config /data/.filebrowser.json`.
 
 use anyhow::{Context, Result};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use tokio::fs;
 
 use crate::update::host_sudo;
@@ -117,6 +117,197 @@ fn shell_quote(s: &str) -> String {
     s.replace('\'', "'\\''")
 }
 
+/// Save a complete purchase without overwriting any existing directory entry.
+/// Both host and rootless-namespace paths publish with a no-clobber hard link.
+pub async fn save_new_file(dir: &Path, name: &str, bytes: &[u8]) -> Result<PathBuf> {
+    save_new_file_with(dir, name, bytes, write_via_userns).await
+}
+
+fn validate_filename(name: &str) -> Result<()> {
+    anyhow::ensure!(
+        !name.is_empty()
+            && name != "."
+            && name != ".."
+            && !name.contains(['/', '\\', '\0'])
+            && name.len() <= 255,
+        "Invalid purchased filename"
+    );
+    Ok(())
+}
+
+async fn save_new_file_with<F, Fut>(
+    dir: &Path,
+    name: &str,
+    bytes: &[u8],
+    fallback: F,
+) -> Result<PathBuf>
+where
+    F: FnOnce(PathBuf, String, Vec<u8>) -> Fut,
+    Fut: std::future::Future<Output = Result<PathBuf>>,
+{
+    validate_filename(name)?;
+    // Never follow a user-created destination directory symlink.
+    match fs::symlink_metadata(dir).await {
+        Ok(meta) => anyhow::ensure!(meta.is_dir(), "Files destination is not a directory"),
+        Err(error) if error.kind() == std::io::ErrorKind::NotFound => {}
+        Err(error) => return Err(error.into()),
+    }
+    save_after_direct_result(
+        write_direct(dir, name, bytes).await,
+        dir,
+        name,
+        bytes,
+        fallback,
+    )
+    .await
+}
+
+async fn save_after_direct_result<F, Fut>(
+    result: std::io::Result<PathBuf>,
+    dir: &Path,
+    name: &str,
+    bytes: &[u8],
+    fallback: F,
+) -> Result<PathBuf>
+where
+    F: FnOnce(PathBuf, String, Vec<u8>) -> Fut,
+    Fut: std::future::Future<Output = Result<PathBuf>>,
+{
+    match result {
+        Ok(path) => Ok(path),
+        Err(error) if error.kind() == std::io::ErrorKind::PermissionDenied => {
+            fallback(dir.to_owned(), name.to_owned(), bytes.to_vec())
+                .await
+                .context("Saving purchase in Files user namespace")
+        }
+        Err(error) => Err(error).context("Saving purchase in Files"),
+    }
+}
+
+fn numbered_name(name: &str, attempt: usize) -> String {
+    if attempt == 1 {
+        return name.to_owned();
+    }
+    match name.rsplit_once('.') {
+        Some((stem, extension)) if !stem.is_empty() => format!("{stem} ({attempt}).{extension}"),
+        _ => format!("{name} ({attempt})"),
+    }
+}
+
+struct PendingFile(PathBuf);
+impl Drop for PendingFile {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_file(&self.0);
+    }
+}
+
+async fn write_direct(dir: &Path, name: &str, bytes: &[u8]) -> std::io::Result<PathBuf> {
+    use std::os::unix::fs::PermissionsExt;
+    use tokio::io::AsyncWriteExt;
+    fs::create_dir_all(dir).await?;
+    let temp_path = dir.join(format!(".archy-saving-{}", uuid::Uuid::new_v4()));
+    let mut file = fs::OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .mode(0o600)
+        .open(&temp_path)
+        .await?;
+    let temp = PendingFile(temp_path);
+    file.write_all(bytes).await?;
+    file.set_permissions(std::fs::Permissions::from_mode(0o644))
+        .await?;
+    file.sync_all().await?;
+    for attempt in 1..=100 {
+        let target = dir.join(numbered_name(name, attempt));
+        match fs::hard_link(&temp.0, &target).await {
+            Ok(()) => return Ok(target),
+            Err(error) if error.kind() == std::io::ErrorKind::AlreadyExists => continue,
+            Err(error) => return Err(error),
+        }
+    }
+    Err(std::io::Error::new(
+        std::io::ErrorKind::AlreadyExists,
+        "Too many existing copies; purchase cache retained",
+    ))
+}
+
+// Positional arguments carry all user-controlled text. mktemp prevents temp-name
+// collisions; ln -T refuses files, symlinks and directories, including races.
+const WRITE_VIA_USERNS: &str = r#"set -eu
+dir=$1
+name=$2
+expected=$3
+[ ! -L "$dir" ] || exit 1
+if [ ! -d "$dir" ]; then
+    mkdir -p -- "$dir"
+    chown --reference="$(dirname -- "$dir")" -- "$dir"
+fi
+tmp=$(mktemp "$dir/.archy-saving.XXXXXXXXXX")
+trap 'rm -f -- "$tmp"' EXIT HUP INT TERM
+cat > "$tmp"
+[ "$(wc -c < "$tmp")" -eq "$expected" ] || exit 1
+chown --reference="$dir" -- "$tmp"
+chmod 0644 -- "$tmp"
+sync -f -- "$tmp"
+stem=$name
+ext=
+case "$name" in
+    *.*) prefix=${name%.*}; if [ -n "$prefix" ]; then stem=$prefix; ext=.${name##*.}; fi ;;
+esac
+n=1
+while [ "$n" -le 100 ]; do
+    candidate=$name
+    if [ "$n" -gt 1 ]; then candidate="$stem ($n)$ext"; fi
+    dst="$dir/$candidate"
+    if ln -T -- "$tmp" "$dst" 2>/dev/null; then
+        printf '%s' "$candidate"
+        exit 0
+    fi
+    # A conflict may be a dangling symlink; never follow it or overwrite it.
+    if [ ! -e "$dst" ] && [ ! -L "$dst" ]; then exit 1; fi
+    n=$((n + 1))
+done
+exit 1
+"#;
+
+async fn write_via_userns(dir: PathBuf, name: String, bytes: Vec<u8>) -> Result<PathBuf> {
+    use tokio::io::AsyncWriteExt;
+    let mut child = tokio::process::Command::new("podman")
+        .args(["unshare", "sh", "-c", WRITE_VIA_USERNS, "sh"])
+        .arg(&dir)
+        .arg(&name)
+        .arg(bytes.len().to_string())
+        .kill_on_drop(true)
+        .stdin(std::process::Stdio::piped())
+        .stdout(std::process::Stdio::piped())
+        .stderr(std::process::Stdio::piped())
+        .spawn()
+        .context("Starting Files namespace writer")?;
+    let mut stdin = child.stdin.take().context("Files writer stdin missing")?;
+    let operation = async {
+        let fed = stdin.write_all(&bytes).await;
+        drop(stdin);
+        let output = child.wait_with_output().await?;
+        anyhow::ensure!(
+            output.status.success(),
+            "Files namespace writer failed: {}",
+            output.status
+        );
+        fed.context("Sending purchase bytes to Files")?;
+        let chosen =
+            String::from_utf8(output.stdout).context("Files writer returned an invalid name")?;
+        validate_filename(&chosen)?;
+        anyhow::ensure!(
+            (1..=100).any(|n| numbered_name(&name, n) == chosen),
+            "Files writer returned an unexpected name"
+        );
+        Ok(dir.join(chosen))
+    };
+    tokio::time::timeout(std::time::Duration::from_secs(120), operation)
+        .await
+        .context("Files namespace writer timed out")?
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -152,3 +343,231 @@ mod tests {
         assert_eq!(second, EnsureOutcome::Unchanged);
     }
 }
+
+#[cfg(test)]
+mod purchase_write_tests {
+    use super::*;
+    use std::{
+        collections::HashSet,
+        os::unix::fs::{symlink, PermissionsExt},
+    };
+
+    fn no_temps(dir: &Path) {
+        assert!(std::fs::read_dir(dir).unwrap().all(|e| !e
+            .unwrap()
+            .file_name()
+            .to_string_lossy()
+            .starts_with(".archy-saving")));
+    }
+
+    #[tokio::test]
+    async fn direct_write_uses_complete_bytes_and_preserves_originals() {
+        let dir = tempfile::tempdir().unwrap();
+        fs::write(dir.path().join("song.mp3"), b"original")
+            .await
+            .unwrap();
+        let target = save_new_file(dir.path(), "song.mp3", b"new").await.unwrap();
+        assert_eq!(target.file_name().unwrap(), "song (2).mp3");
+        assert_eq!(fs::read(target).await.unwrap(), b"new");
+        assert_eq!(
+            fs::read(dir.path().join("song.mp3")).await.unwrap(),
+            b"original"
+        );
+        no_temps(dir.path());
+    }
+
+    #[tokio::test]
+    async fn simultaneous_saves_publish_unique_complete_files() {
+        let dir = tempfile::tempdir().unwrap();
+        let mut tasks = Vec::new();
+        for n in 0..24u8 {
+            let dir = dir.path().to_owned();
+            tasks.push(tokio::spawn(async move {
+                let bytes = vec![n; 32768];
+                let path = save_new_file(&dir, "same.bin", &bytes).await.unwrap();
+                assert_eq!(fs::read(&path).await.unwrap(), bytes);
+                path
+            }));
+        }
+        let mut paths = HashSet::new();
+        for task in tasks {
+            assert!(paths.insert(task.await.unwrap()));
+        }
+        assert_eq!(paths.len(), 24);
+        no_temps(dir.path());
+    }
+
+    #[tokio::test]
+    async fn existing_directories_and_dangling_symlinks_are_conflicts() {
+        let dir = tempfile::tempdir().unwrap();
+        fs::create_dir(dir.path().join("name")).await.unwrap();
+        symlink("missing", dir.path().join("name (2)")).unwrap();
+        let path = save_new_file(dir.path(), "name", b"new").await.unwrap();
+        assert_eq!(path.file_name().unwrap(), "name (3)");
+        assert!(dir.path().join("name").is_dir());
+        assert!(fs::symlink_metadata(dir.path().join("name (2)"))
+            .await
+            .unwrap()
+            .is_symlink());
+        no_temps(dir.path());
+    }
+
+    #[tokio::test]
+    async fn invalid_names_and_symlink_destination_are_refused() {
+        let dir = tempfile::tempdir().unwrap();
+        for name in [
+            "",
+            ".",
+            "..",
+            "../escape",
+            "/absolute",
+            "a/b",
+            "a\\b",
+            "a\0b",
+        ] {
+            assert!(save_new_file(dir.path(), name, b"bytes").await.is_err());
+        }
+        let outside = tempfile::tempdir().unwrap();
+        symlink(outside.path(), dir.path().join("Music")).unwrap();
+        assert!(save_new_file(&dir.path().join("Music"), "song", b"bytes")
+            .await
+            .is_err());
+        assert_eq!(std::fs::read_dir(outside.path()).unwrap().count(), 0);
+    }
+
+    #[tokio::test]
+    async fn collision_limit_preserves_all_files_and_cleans_temporary_data() {
+        let dir = tempfile::tempdir().unwrap();
+        for n in 1..=100 {
+            fs::write(dir.path().join(numbered_name("a.txt", n)), b"keep")
+                .await
+                .unwrap();
+        }
+        assert!(save_new_file(dir.path(), "a.txt", b"new").await.is_err());
+        for n in 1..=100 {
+            assert_eq!(
+                fs::read(dir.path().join(numbered_name("a.txt", n)))
+                    .await
+                    .unwrap(),
+                b"keep"
+            );
+        }
+        no_temps(dir.path());
+    }
+
+    #[tokio::test]
+    async fn permission_fallback_is_exercised_without_skipping_as_root() {
+        let dir = tempfile::tempdir().unwrap();
+        let result = save_after_direct_result(
+            Err(std::io::ErrorKind::PermissionDenied.into()),
+            dir.path(),
+            "a",
+            b"abc",
+            |dir, name, bytes| async move {
+                assert_eq!(bytes, b"abc");
+                Ok(dir.join(name))
+            },
+        )
+        .await
+        .unwrap();
+        assert_eq!(result, dir.path().join("a"));
+        assert!(save_after_direct_result(
+            Err(std::io::ErrorKind::PermissionDenied.into()),
+            dir.path(),
+            "a",
+            b"abc",
+            |_, _, _| async { anyhow::bail!("namespace unavailable") }
+        )
+        .await
+        .unwrap_err()
+        .to_string()
+        .contains("namespace"));
+        assert!(save_after_direct_result(
+            Err(std::io::ErrorKind::StorageFull.into()),
+            dir.path(),
+            "a",
+            b"abc",
+            |_, _, _| async { panic!("disk full must not trigger permission fallback") }
+        )
+        .await
+        .is_err());
+    }
+
+    async fn run_script(
+        dir: &Path,
+        name: &str,
+        bytes: &[u8],
+        expected: usize,
+    ) -> std::process::Output {
+        use tokio::io::AsyncWriteExt;
+        let mut child = tokio::process::Command::new("sh")
+            .args(["-c", WRITE_VIA_USERNS, "sh"])
+            .arg(dir)
+            .arg(name)
+            .arg(expected.to_string())
+            .stdin(std::process::Stdio::piped())
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+            .unwrap();
+        let mut input = child.stdin.take().unwrap();
+        input.write_all(bytes).await.unwrap();
+        drop(input);
+        child.wait_with_output().await.unwrap()
+    }
+
+    #[tokio::test]
+    async fn namespace_script_preserves_names_bytes_modes_and_existing_entries() {
+        let dir = tempfile::tempdir().unwrap();
+        let folder = dir.path().join("Music");
+        let name = "song ' $() ; #.mp3";
+        for n in 1..=2 {
+            let output = run_script(&folder, name, b"abc", 3).await;
+            assert!(
+                output.status.success(),
+                "{}",
+                String::from_utf8_lossy(&output.stderr)
+            );
+            let chosen = String::from_utf8(output.stdout).unwrap();
+            assert_eq!(chosen, numbered_name(name, n));
+            let path = folder.join(chosen);
+            assert_eq!(fs::read(&path).await.unwrap(), b"abc");
+            assert_eq!(
+                fs::metadata(path).await.unwrap().permissions().mode() & 0o777,
+                0o644
+            );
+        }
+        no_temps(&folder);
+    }
+
+    #[tokio::test]
+    async fn namespace_script_refuses_truncated_input_and_cleans_up() {
+        let dir = tempfile::tempdir().unwrap();
+        let output = run_script(dir.path(), "never.bin", b"partial", 100).await;
+        assert!(!output.status.success());
+        assert!(!dir.path().join("never.bin").exists());
+        no_temps(dir.path());
+    }
+
+    #[tokio::test]
+    async fn namespace_script_does_not_link_inside_existing_directory() {
+        let dir = tempfile::tempdir().unwrap();
+        fs::create_dir(dir.path().join("name")).await.unwrap();
+        symlink("missing", dir.path().join("name (2)")).unwrap();
+        let output = run_script(dir.path(), "name", b"abc", 3).await;
+        assert!(output.status.success());
+        assert_eq!(output.stdout, b"name (3)");
+        assert_eq!(
+            std::fs::read_dir(dir.path().join("name")).unwrap().count(),
+            0
+        );
+        no_temps(dir.path());
+    }
+
+    #[test]
+    fn names_keep_extensions_and_dotfiles() {
+        assert_eq!(numbered_name("a.tar.gz", 2), "a.tar (2).gz");
+        assert_eq!(numbered_name(".hidden", 2), ".hidden (2)");
+        assert_eq!(numbered_name("README", 2), "README (2)");
+    }
+}

docs/TODO.md

@@ -14,17 +14,6 @@ doc. See [`ROADMAP.md`](ROADMAP.md) for the curated, public-facing direction.
 
 ## Next release after 1.8.21 — reported 2026-09-30
 
-- [x] Review and repair open paid-download PRs #161 and #162, refresh both
-  branches from main, run independent and combined isolated suites, and verify
-  rootless file permissions in disposable scratch storage. Combined result:
-  1,585 passed, zero failed, four existing tests ignored. See the
-  [review evidence and remaining acceptance work](pr-review-20260930.md).
-- [ ] Integrate the reviewed PR branches into the next release and run funded
-  candidate acceptance, including Tor-only transport and payments with change.
-  PRs remain open; the reviewed code has not been deployed to live wallets.
-- [ ] Design durable recovery for an accepted payment whose response is lost.
-  Preserve the truthful unconfirmed-refund warning and prevent automatic
-  duplicate payment while that recovery work is outstanding.
 - [ ] **ThinkPad X250 kiosk: Bitcoin installation version selector is unreadable
   and appears underneath the pruning information.** Operator reports white
   styling with invisible text on the actual kiosk; the same flow works in remote
@@ -39,21 +28,20 @@ doc. See [`ROADMAP.md`](ROADMAP.md) for the curated, public-facing direction.
   alone do not establish that the kiosk rendering is fixed. Track for the next
   release; the signed 1.8.21 artifacts remain unchanged.
 
-## 1.8.21 repair and release tasks — completed 2026-09-30
+## Current repair and release tasks — 2026-09-29
 
-See the [execution record](repair-release-20260929.md) for evidence and limits.
+Release is blocked until these pass; see [execution record](repair-release-20260929.md).
 
-- [x] Fix Cashu paid-file redemption between dev and Shorty; test keyset IDs,
+- [ ] Fix Cashu paid-file redemption between dev and Shorty; test keyset IDs,
   mint errors, fees, and refund reporting before live validation.
-- [x] Record Framework verification and the operator's acceptance of the
-  remaining display check before release.
-- [x] Replace the unavailable tx1138.com explorer default with mempool.space;
+- [ ] Complete the remaining Framework incident verification and evidence.
+- [ ] Replace the unavailable tx1138.com explorer default with mempool.space;
   migrate the old default with fresh consent and preserve custom/local explorers.
-- [x] Offer pruning in the Bitcoin installation version modal, using the same
+- [ ] Offer pruning in the Bitcoin installation version modal, using the same
   pruning settings as automatic pruning even on large disks.
-- [x] Explain Bitcoin warmup without raw RPC errors; gate LND unlock on Bitcoin
+- [ ] Explain Bitcoin warmup without raw RPC errors; gate LND unlock on Bitcoin
   RPC readiness and show install/start/sync waiting states with automatic recovery.
-- [x] Test the completed changes on this development box, then publish a new
+- [ ] Test the completed changes on this development box, then publish a new
   signed OTA and raw ISO release. Record any remaining verification gaps.
 
 ## Dev & build process (priority)

docs/pr-review-20260930.md

@@ -1,113 +0,0 @@
-# Paid-download PR review — 2026-09-30
-
-## Scope and result
-
-Reviewed both open PRs from the repository pull-request list: [#161](https://source.archipelago-foundation.org/lfg2025/archy/pulls/161)
-and [#162](https://source.archipelago-foundation.org/lfg2025/archy/pulls/162).
-Both branches were updated from main, repaired and tested independently and
-together. Their existing remote branches were advanced without rewriting the
-contributors' history. They remain open for integration into the release after
-1.8.21; no reviewed code was merged into main or deployed to a live wallet.
-The signed 1.8.21 artifacts are unchanged.
-
-| Candidate | Tested commit | Isolated backend result |
-| --- | --- | --- |
-| PR #161 | `971d4777` | 1,576 passed, 0 failed, 4 existing tests ignored |
-| PR #162 | `0677924a` | 1,568 passed, 0 failed, 4 existing tests ignored |
-| Both together | `4bf4bf1a` | 1,585 passed, 0 failed, 4 existing tests ignored |
-
-Both individual branches also passed production `cargo check`, with the
-repository's existing 16 warnings. The combined merge required no conflict
-resolution. Backend tests ran through `scripts/test-backend-isolated.sh` so they
-could not access host wallets, native services or production container storage.
-
-## Findings and repairs
-
-### #161 — payment delivery and file readability
-
-- The branch conflicted with newer mint-fee, keyset-ID and truthful refund
-  reporting fixes. Preserve those implementations from main; do not reintroduce
-  its older unconditional “refunded” messages or duplicate keyset resolution.
-- Opening a file before charging, then reopening/reading it afterward, still
-  permits a read failure after payment. Prepare the complete requested bytes
-  before redemption, including ranged reads. Tests delete or alter the backing
-  file during payment verification and still receive the prepared original data.
-- Empty/out-of-bounds/reversed ranges could fail after redemption, and empty
-  files could underflow the range calculation. Validate ranges before charging
-  and return HTTP 416 when unsatisfiable.
-- `chmod a+r` unnecessarily changed the permissions of shared paid/private
-  files. Read restricted FileBrowser files through the rootless namespace while
-  retaining their mode. Scope the fallback to regular files canonically inside
-  FileBrowser storage, and reject unauthorized peers before reading.
-- A single-delivery flag must also prevent redirects and ambiguous transport
-  retries. Payment-bearing GET and POST requests now retain the first HTTP
-  response and do not retry after timeouts or disconnects that might follow
-  delivery. Refused connections and normal nonpayment browsing retain the
-  appropriate retry behavior.
-- Interrupted response bodies now report the outcome using the actual local
-  refund result. Seller explanations are bounded, stripped of control
-  characters and explicitly identified as peer text.
-- Original permission tests silently returned when run as root. Replacement
-  tests inject read/payment boundary failures, exercise them under the isolated
-  runner, and assert that read failures never invoke redemption.
-
-### #162 — saving purchases in Files
-
-- Its host-permission repair overlapped 1.8.21's authenticated Files API path.
-  Review of [FileBrowser v2.63.23's resource handler](https://github.com/filebrowser/filebrowser/blob/v2.63.23/http/resource.go)
-  showed that `override=false` checks for existence separately from opening
-  with truncation. It does not guarantee no overwrites under concurrent saves.
-- The proposed direct path exposed the final filename before the write
-  completed. Both direct and namespace paths now finish a private temporary
-  file and publish it through a no-clobber hard link, retrying numbered names.
-- Plain `ln` could place a temporary file inside an existing directory instead
-  of treating the destination as a collision. Use `ln -T`; existing directories
-  and dangling symlinks are conflicts, never replacement targets.
-- Add filename and destination checks, unique temporary names, bounded name
-  retries, synchronization before publication, and exact input-length checks.
-  Truncated pipe input cannot become a completed purchased file.
-- Files storage remains optional. An unavailable copy destination does not
-  undo the purchase or create a fake FileBrowser installation; the durable
-  purchased-content cache remains primary.
-
-## Additional verification on the development node
-
-Used disposable scratch directories only, then removed them:
-
-- Reproduced a FileBrowser-style rootless-owned 0640 upload. The host backend
-  UID could not read it. `podman unshare cat` returned identical bytes without
-  changing its 0640 mode.
-- Ran the exact namespace writer script with four concurrent writers against
-  a directory owned by the container UID range. Every file had unique naming,
-  exact bytes, the expected owner and mode, and no remaining temporary file.
-- Sent truncated input to the namespace writer and verified refusal, no final
-  file and temporary-file cleanup.
-
-The isolated tests additionally exercised 24 simultaneous direct writes,
-existing-file preservation, symlink/directory conflicts, collision exhaustion,
-root-independent permission failures, read-before-redemption ordering,
-authorization, redirects and peer disconnects.
-
-Logs on the development box:
-`/tmp/archy-pr161-tests.log`, `/tmp/archy-pr162-tests.log`,
-`/tmp/archy-pr-integration-tests.log`, `/tmp/archy-pr161-check.log`,
-`/tmp/archy-pr162-check.log`, `/tmp/archy-pr-userns-scratch-test.log`.
-
-## Next-release acceptance and limits
-
-- Integrate the reviewed branches and repeat the release gates against the
-  final release commit if additional code changes land.
-- Perform funded peer-to-peer acceptance on the candidate build, including a
-  Tor-only purchase and a purchase requiring change, before the next release.
-  The new review branches were not deployed to funded live wallets here.
-- These PRs do not implement durable payment receipts. If a seller redeems a
-  payment and the connection subsequently loses the response, the buyer may
-  receive an unconfirmed-refund warning. Do not represent that warning as proof
-  of a refund or automatically charge the buyer again. Receipt-based recovery
-  remains separate follow-up work.
-- Abrupt process termination can leave a hidden namespace temporary file;
-  ordinary write failures and truncated input are tested to clean up. The final
-  filename is published only after complete input, and existing files remain
-  protected.
-- The separately reported X250 kiosk version-selector rendering issue remains
-  open in `TODO.md` and requires validation on the actual kiosk.

docs/repair-release-20260929.md

@@ -356,42 +356,3 @@ Bitcoin and LND IDs/start times remained unchanged, with generated stop settings
 still verified. No temporary graceful-stop overrides remain. Catalog signature
 verifies against the pinned release root; final 1.8.21 artifact validator passes.
 The candidate is ready for the user's local OTA signing ceremony.
-
-### 1.8.21 publication completed — 2026-09-30
-
-The operator signed the OTA manifest and subsequently the ISO checksum JSON.
-Both signatures verified against the pinned release root. The signed OTA was
-published on git/ngit, and the operator confirmed that Framework could see the
-update. Source main and the annotated `v1.8.21-alpha` tag were published.
-
-Raw ISO:
-`archipelago-installer-1.8.21-alpha-unbundled-x86_64_RC1.iso`
-
-- Size: 2,682,419,200 bytes.
-- SHA256: `8667b5522c476a40e29abba19df4180086191527a194a88765aa70ed527f9406`.
-- Build and ISO smoke checks passed. The mounted backend matched the staged
-  OTA backend hash, and the full dashboard/AIUI tree matched the fresh build.
-- An isolated UEFI QEMU guest, with no network or host disks attached, booted to
-  the installer prompt. The VM was stopped and the ISO unmounted afterward.
-  This was an installer boot check, not a full installation onto hardware.
-- Uploaded the raw ISO, plain SHA256 sidecar and signed checksum JSON to the
-  [1.8.21 release](https://source.archipelago-foundation.org/lfg2025/archy/releases/tag/v1.8.21-alpha).
-  The stored server file hashes matched, the public ISO headers and first/last
-  byte samples matched, and both public checksum files matched byte-for-byte.
-- The ngit downloader's full-ISO acquisition exceeded its fixed 30-minute
-  deadline on the available connection. Published Nostr asset records using
-  the already verified hashes, sizes and public URLs with the existing ngit
-  signer; both repository relays acknowledged them. Ngit then accepted those
-  records and final readback resolved all five release assets with the expected
-  hashes and sizes. No new release-root signing was performed by the assistant.
-
-Final publication evidence: `/tmp/archy-1821-finish-events.log`,
-`/tmp/archy-ngit-1821-complete-view.json`, and
-`/tmp/archy-1821-verified-asset-events.log` on the development box.
-
-Subsequent review of PRs #161/#162 found additional delivery and concurrent
-file-save edge cases. Their repaired, tested branches are recorded in
-[the next-release review](pr-review-20260930.md); those changes are not in the
-signed 1.8.21 artifacts. The X250 kiosk selector report is also tracked for the
-next release. No claim of exhaustive hardware or network-failure coverage is
-made for this release.