src/client/backup_reader.rs: factor out download_blob() helper

src/bin/proxmox-backup-client.rs

@@ -8,7 +8,7 @@ use chrono::{Local, Utc, TimeZone};
 use std::path::{Path, PathBuf};
 use std::collections::{HashSet, HashMap};
 use std::ffi::OsStr;
-use std::io::{Read, Write, Seek, SeekFrom};
+use std::io::{Write, Seek, SeekFrom};
 use std::os::unix::fs::OpenOptionsExt;
 
 use proxmox::tools::fs::{file_get_contents, file_get_json, file_set_contents, image_size};
@@ -152,33 +152,6 @@ fn complete_repository(_arg: &str, _param: &HashMap<String, String>) -> Vec<Stri
     result
 }
 
-fn compute_file_csum(file: &mut std::fs::File) -> Result<([u8; 32], u64), Error> {
-
-    file.seek(SeekFrom::Start(0))?;
-
-    let mut hasher = openssl::sha::Sha256::new();
-    let mut buffer = proxmox::tools::vec::undefined(256*1024);
-    let mut size: u64 = 0;
-
-    loop {
-        let count = match file.read(&mut buffer) {
-            Ok(count) => count,
-            Err(ref err) if err.kind() == std::io::ErrorKind::Interrupted => { continue; }
-            Err(err) => return Err(err.into()),
-        };
-        if count == 0 {
-            break;
-        }
-        size += count as u64;
-        hasher.update(&buffer[..count]);
-    }
-
-    let csum = hasher.finish();
-
-    Ok((csum, size))
-}
-
-
 async fn backup_directory<P: AsRef<Path>>(
     client: &BackupWriter,
     dir_path: P,
@@ -1020,12 +993,6 @@ async fn restore_do(param: Value) -> Result<Value, Error> {
         true,
     ).await?;
 
-    let tmpfile = std::fs::OpenOptions::new()
-        .write(true)
-        .read(true)
-        .custom_flags(libc::O_TMPFILE)
-        .open("/tmp")?;
-
     let manifest = client.download_manifest().await?;
 
     if server_archive_name == MANIFEST_BLOB_NAME {
@@ -1040,13 +1007,8 @@ async fn restore_do(param: Value) -> Result<Value, Error> {
         }
 
     } else if server_archive_name.ends_with(".blob") {
-        let mut tmpfile = client.download(&server_archive_name, tmpfile).await?;
 
-        let (csum, size) = compute_file_csum(&mut tmpfile)?;
-        manifest.verify_file(&server_archive_name, &csum, size)?;
-
-        tmpfile.seek(SeekFrom::Start(0))?;
-        let mut reader = DataBlobReader::new(tmpfile, crypt_config)?;
+        let mut reader = client.download_blob(&manifest, &server_archive_name).await?;
 
         if let Some(target) = target {
            let mut writer = std::fs::OpenOptions::new()

src/client/backup_reader.rs

@@ -1,5 +1,6 @@
 use failure::*;
-use std::io::Write;
+use std::io::{Read, Write, Seek, SeekFrom};
+use std::fs::File;
 use std::sync::Arc;
 use std::os::unix::fs::OpenOptionsExt;
 
@@ -135,6 +136,32 @@ impl BackupReader {
         BackupManifest::try_from(json)
     }
 
+    /// Download a .blob file
+    ///
+    /// This creates a temorary file in /tmp (using O_TMPFILE). The data is verified using
+    /// the provided manifest.
+    pub async fn download_blob(
+        &self,
+        manifest: &BackupManifest,
+        name: &str,
+    ) -> Result<DataBlobReader<File>, Error> {
+
+        let tmpfile = std::fs::OpenOptions::new()
+            .write(true)
+            .read(true)
+            .custom_flags(libc::O_TMPFILE)
+            .open("/tmp")?;
+
+        let mut tmpfile = self.download(name, tmpfile).await?;
+
+        let (csum, size) = compute_file_csum(&mut tmpfile)?;
+        manifest.verify_file(name, &csum, size)?;
+
+        tmpfile.seek(SeekFrom::Start(0))?;
+
+        DataBlobReader::new(tmpfile, self.crypt_config.clone())
+    }
+
     /// Download dynamic index file
     ///
     /// This creates a temorary file in /tmp (using O_TMPFILE). The index is verified using
@@ -191,3 +218,29 @@ impl BackupReader {
         Ok(index)
     }
 }
+
+fn compute_file_csum(file: &mut File) -> Result<([u8; 32], u64), Error> {
+
+    file.seek(SeekFrom::Start(0))?;
+
+    let mut hasher = openssl::sha::Sha256::new();
+    let mut buffer = proxmox::tools::vec::undefined(256*1024);
+    let mut size: u64 = 0;
+
+    loop {
+        let count = match file.read(&mut buffer) {
+            Ok(count) => count,
+            Err(ref err) if err.kind() == std::io::ErrorKind::Interrupted => { continue; }
+            Err(err) => return Err(err.into()),
+        };
+        if count == 0 {
+            break;
+        }
+        size += count as u64;
+        hasher.update(&buffer[..count]);
+    }
+
+    let csum = hasher.finish();
+
+    Ok((csum, size))
+}