[pve-devel] [PATCH proxmox v5 4/4] apt: check for local POM InRelease as fallback

[Nicolas Frey]

Add local file fallback in case that the URI starts with `file://`,
which is useful if a POM repo is stored on a medium. This improves
UX by not necessarily needing to apt update to see immediate feedback
in the Repositories UI of pve/pbs.

If the medium is not present, the signature verification will simply
fail.

Signed-off-by: Nicolas Frey <n.frey at proxmox.com>
---
 proxmox-apt/src/repositories/repository.rs | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/proxmox-apt/src/repositories/repository.rs b/proxmox-apt/src/repositories/repository.rs
index 1b3f010e..b8b2ecc4 100644
--- a/proxmox-apt/src/repositories/repository.rs
+++ b/proxmox-apt/src/repositories/repository.rs
@@ -396,12 +396,7 @@ fn write_stanza(repo: &APTRepository, w: &mut dyn Write) -> Result<(), Error> {
 /// Reads file contents of cached/local POM InRelease file from uri
 /// and key to verify pgp signature
 fn is_signed_by_key(uri: &str, suite: &str, key_path: &str) -> bool {
-    let data = match std::fs::read(&release_filename(
-        Path::new("/var/lib/apt/lists"),
-        uri,
-        suite,
-        false,
-    )) {
+    let data = match read_inrelease(uri, suite) {
         Ok(d) => d,
         Err(err) => {
             log::warn!("could not read InRelease file: {err}");
@@ -425,6 +420,20 @@ fn is_signed_by_key(uri: &str, suite: &str, key_path: &str) -> bool {
     true
 }
 
+/// Reads cached/local POM InRelease file
+fn read_inrelease(uri: &str, suite: &str) -> Result<Vec<u8>, Error> {
+    let path = release_filename(Path::new("/var/lib/apt/lists"), uri, suite, false);
+
+    if path.exists() {
+        std::fs::read(&path).map_err(Into::into)
+    } else if let Some(local_path) = uri.strip_prefix("file://") {
+        let inrelease_path = format!("{}/dists/{}/InRelease", local_path, suite);
+        std::fs::read(&inrelease_path).map_err(Into::into)
+    } else {
+        bail!("Unsupported URI scheme: {}", uri);
+    }
+}
+
 #[test]
 fn test_uri_to_filename() {
     let filename = uri_to_filename("https://some_host/some/path");
-- 
2.47.3