TapeRead: add skip_data()

src/api2/tape/restore.rs

@@ -525,7 +525,7 @@ fn restore_archive<'a>(
                 }
             }
 
-            reader.skip_to_end()?; // read all data
+            reader.skip_data()?; // read all data
             if let Ok(false) = reader.is_incomplete() {
                 catalog.register_snapshot(Uuid::from(header.uuid), current_file_number, &datastore_name, &snapshot)?;
                 catalog.commit_if_large()?;
@@ -566,7 +566,7 @@ fn restore_archive<'a>(
                 task_log!(worker, "skipping...");
             }
 
-            reader.skip_to_end()?; // read all data
+            reader.skip_data()?; // read all data
         }
         PROXMOX_BACKUP_CATALOG_ARCHIVE_MAGIC_1_0 => {
             let header_data = reader.read_exact_allocated(header.size as usize)?;
@@ -576,7 +576,7 @@ fn restore_archive<'a>(
 
             task_log!(worker, "File {}: skip catalog '{}'", current_file_number, archive_header.uuid);
 
-            reader.skip_to_end()?; // read all data
+            reader.skip_data()?; // read all data
         }
          _ =>  bail!("unknown content magic {:?}", header.content_magic),
     }
@@ -849,7 +849,7 @@ pub fn fast_catalog_restore(
 
                 if &archive_header.media_set_uuid != media_set.uuid() {
                     task_log!(worker, "skipping unrelated catalog at pos {}", current_file_number);
-                    reader.skip_to_end()?; // read all data
+                    reader.skip_data()?; // read all data
                     continue;
                 }
 
@@ -868,7 +868,7 @@ pub fn fast_catalog_restore(
 
                 if !wanted {
                     task_log!(worker, "skip catalog because media '{}' not inventarized", catalog_uuid);
-                    reader.skip_to_end()?; // read all data
+                    reader.skip_data()?; // read all data
                     continue;
                 }
 
@@ -878,7 +878,7 @@ pub fn fast_catalog_restore(
                     // only restore if catalog does not exist
                     if MediaCatalog::exists(status_path, catalog_uuid) {
                         task_log!(worker, "catalog for media '{}' already exists", catalog_uuid);
-                        reader.skip_to_end()?; // read all data
+                        reader.skip_data()?; // read all data
                         continue;
                     }
                 }

src/bin/proxmox-tape.rs

@@ -622,8 +622,15 @@ fn debug_scan(mut param: Value) -> Result<(), Error> {
                         println!("unable to read content header - {}", err);
                     }
                 }
-                let bytes = reader.skip_to_end()?;
+                let bytes = reader.skip_data()?;
                 println!("skipped {}", HumanByte::from(bytes));
+                if let Ok(true) = reader.has_end_marker() {
+                    if reader.is_incomplete()? {
+                        println!("WARNING: file is incomplete");
+                    }
+                } else {
+                    println!("WARNING: file without end marker");
+                }
             }
         }
     }

src/tape/file_formats/blocked_reader.rs

@@ -129,14 +129,14 @@ impl <R: BlockRead> BlockedReader<R> {
         }
     }
 
-    fn read_block(&mut self) -> Result<usize, std::io::Error> {
+    fn read_block(&mut self, check_end_marker: bool) -> Result<usize, std::io::Error> {
 
         match Self::read_block_frame(&mut self.buffer, &mut self.reader) {
             Ok(()) => { /* ok */ }
             Err(BlockReadError::EndOfFile) => {
                 self.got_eod = true;
                 self.read_pos = self.buffer.payload.len();
-                if !self.found_end_marker {
+                if !self.found_end_marker && check_end_marker {
                     proxmox::io_bail!("detected tape stream without end marker");
                 }
                 return Ok(0); // EOD
@@ -185,6 +185,23 @@ impl <R: BlockRead> TapeRead for BlockedReader<R> {
 
         Ok(self.found_end_marker)
     }
+
+    // like ReadExt::skip_to_end(), but does not raise an error if the
+    // stream has no end marker.
+    fn skip_data(&mut self) -> Result<usize, std::io::Error> {
+        let mut bytes = 0;
+        let buffer_size = self.buffer.size();
+        let rest = (buffer_size as isize) - (self.read_pos as isize);
+        if rest > 0 {
+            bytes = rest as usize;
+        }
+        loop {
+            if self.got_eod {
+                return Ok(bytes);
+            }
+            bytes += self.read_block(false)?;
+        }
+    }
 }
 
 impl <R: BlockRead> Read for BlockedReader<R> {
@@ -199,7 +216,7 @@ impl <R: BlockRead> Read for BlockedReader<R> {
         let mut rest = (buffer_size as isize) - (self.read_pos as isize);
 
         if rest <= 0 && !self.got_eod { // try to refill buffer
-            buffer_size = match self.read_block() {
+            buffer_size = match self.read_block(true) {
                 Ok(len) => len,
                 err => {
                     self.read_error = true;

src/tape/tape_read.rs

@@ -13,6 +13,12 @@ pub trait TapeRead: Read {
     ///
     /// Raises an error if you query this flag before reaching EOF.
     fn has_end_marker(&self) -> Result<bool, std::io::Error>;
+
+    /// Skip data by reading to EOF (position after EOF marker)
+    ///
+    // Returns the number of bytes skipped. This does not raise an
+    // error if the stream has no end marker.
+    fn skip_data(&mut self) -> Result<usize, std::io::Error>;
 }
 
 #[derive(thiserror::Error, Debug)]