[pbs-devel] [PATCH v5 proxmox-backup 4/4] add index recovery to pb-debug

[Hannes Laimer <h.laimer@proxmox.com>]

Adds possibility to recover data from an index file. Options:
 - chunks: path to the directory where the chunks are saved
 - file: the index file that should be recovered(must be either .fidx or
   didx)
 - [opt] keyfile: path to a keyfile, if the data was encrypted, a keyfile is
   needed
 - [opt] skip-crc: boolean, if true, read chunks wont be verified with their
   crc-sum, increases the restore speed by a lot

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
---
v5:
 - try to load decryption key at the beginning
 - simplified usage of the key
 - allocate 4 MiB for chunks instead of 1 MiB

v4:
 - there might be a better way to do the match magic block

 src/bin/proxmox-backup-debug.rs         |   6 +-
 src/bin/proxmox_backup_debug/mod.rs     |   2 +
 src/bin/proxmox_backup_debug/recover.rs | 115 ++++++++++++++++++++++++
 3 files changed, 121 insertions(+), 2 deletions(-)
 create mode 100644 src/bin/proxmox_backup_debug/recover.rs

diff --git a/src/bin/proxmox-backup-debug.rs b/src/bin/proxmox-backup-debug.rs
index fb548a31..83328701 100644
--- a/src/bin/proxmox-backup-debug.rs
+++ b/src/bin/proxmox-backup-debug.rs
@@ -2,7 +2,7 @@ use proxmox::api::cli::*;
 use proxmox::api::schema::{Schema, StringSchema};
 
 mod proxmox_backup_debug;
-use proxmox_backup_debug::inspect_commands;
+use proxmox_backup_debug::{inspect_commands, recover_commands};
 
 pub mod proxmox_client_tools;
 use proxmox_client_tools::key_source::{get_encryption_key_password, KEYFILE_SCHEMA};
@@ -12,7 +12,9 @@ pub const PATH_SCHEMA: Schema = StringSchema::new("Path to a file or a directory
 fn main() {
     proxmox_backup::tools::setup_safe_path_env();
 
-    let cmd_def = CliCommandMap::new().insert("inspect", inspect_commands());
+    let cmd_def = CliCommandMap::new()
+        .insert("inspect", inspect_commands())
+        .insert("recover", recover_commands());
 
     let rpcenv = CliEnvironment::new();
     run_cli_command(
diff --git a/src/bin/proxmox_backup_debug/mod.rs b/src/bin/proxmox_backup_debug/mod.rs
index 644583db..62df7754 100644
--- a/src/bin/proxmox_backup_debug/mod.rs
+++ b/src/bin/proxmox_backup_debug/mod.rs
@@ -1,2 +1,4 @@
 mod inspect;
 pub use inspect::*;
+mod recover;
+pub use recover::*;
diff --git a/src/bin/proxmox_backup_debug/recover.rs b/src/bin/proxmox_backup_debug/recover.rs
new file mode 100644
index 00000000..2355b50f
--- /dev/null
+++ b/src/bin/proxmox_backup_debug/recover.rs
@@ -0,0 +1,115 @@
+use std::fs::File;
+use std::io::{Read, Seek, SeekFrom, Write};
+use std::path::Path;
+
+use anyhow::{format_err, Error};
+
+use proxmox::api::api;
+use proxmox::api::cli::{CliCommand, CliCommandMap, CommandLineInterface};
+use proxmox_backup::backup::{DYNAMIC_SIZED_CHUNK_INDEX_1_0, FIXED_SIZED_CHUNK_INDEX_1_0};
+use serde_json::Value;
+
+use proxmox_backup::backup::{
+    load_and_decrypt_key, CryptConfig, DataBlob, DynamicIndexReader, FixedIndexReader, IndexFile,
+};
+
+use crate::{get_encryption_key_password, KEYFILE_SCHEMA, PATH_SCHEMA};
+
+use proxmox::tools::digest_to_hex;
+
+#[api(
+    input: {
+        properties: {
+            file: {
+                schema: PATH_SCHEMA,
+            },
+            chunks: {
+                schema: PATH_SCHEMA,
+            },
+            "keyfile": {
+                schema: KEYFILE_SCHEMA,
+                optional: true,
+            },
+            "skip-crc": {
+                type: Boolean,
+                optional: true,
+                default: false,
+                description: "Skip the crc verification, increases the restore speed immensely",
+            }
+        }
+    }
+)]
+/// Restore the data from an index file, given the directory of where chunks
+/// are saved, the index file and a keyfile, if needed for decryption.
+fn recover_index(
+    file: String,
+    chunks: String,
+    keyfile: Option<String>,
+    skip_crc: bool,
+    _param: Value,
+) -> Result<(), Error> {
+    let file_path = Path::new(&file);
+    let chunks_path = Path::new(&chunks);
+
+    let key_file_path = keyfile.as_ref().map(Path::new);
+
+    let mut file = File::open(Path::new(&file))?;
+    let mut magic = [0; 8];
+    file.read_exact(&mut magic)?;
+    file.seek(SeekFrom::Start(0))?;
+    let index: Box<dyn IndexFile> = match magic {
+        FIXED_SIZED_CHUNK_INDEX_1_0 => {
+            Ok(Box::new(FixedIndexReader::new(file)?) as Box<dyn IndexFile>)
+        }
+        DYNAMIC_SIZED_CHUNK_INDEX_1_0 => {
+            Ok(Box::new(DynamicIndexReader::new(file)?) as Box<dyn IndexFile>)
+        }
+        _ => Err(format_err!(
+            "index file must either be a .fidx or a .didx file"
+        )),
+    }?;
+
+    let mut crypt_conf_opt = None;
+
+    if key_file_path.is_some() {
+        let (key, _created, _fingerprint) =
+            load_and_decrypt_key(&key_file_path.unwrap(), &get_encryption_key_password)?;
+        crypt_conf_opt = Some(CryptConfig::new(key)?);
+    }
+
+    let output_filename = file_path.file_stem().unwrap().to_str().unwrap();
+    let output_path = Path::new(output_filename);
+    let mut output_file = File::create(output_path)
+        .map_err(|e| format_err!("could not create output file - {}", e))?;
+
+    let mut data = Vec::with_capacity(4 * 1024 * 1024);
+    for pos in 0..index.index_count() {
+        let chunk_digest = index.index_digest(pos).unwrap();
+        let digest_str = digest_to_hex(chunk_digest);
+        let digest_prefix = &digest_str[0..4];
+        let chunk_path = chunks_path.join(digest_prefix).join(digest_str);
+        let mut chunk_file = std::fs::File::open(&chunk_path)
+            .map_err(|e| format_err!("could not open chunk file - {}", e))?;
+
+        data.clear();
+        chunk_file.read_to_end(&mut data)?;
+        let chunk_blob = DataBlob::from_raw(data.clone())?;
+
+        if !skip_crc {
+            chunk_blob.verify_crc()?;
+        }
+
+        output_file.write_all(
+            chunk_blob
+                .decode(crypt_conf_opt.as_ref(), Some(chunk_digest))?
+                .as_slice(),
+        )?;
+    }
+
+    Ok(())
+}
+
+pub fn recover_commands() -> CommandLineInterface {
+    let cmd_def = CliCommandMap::new().insert("index", CliCommand::new(&API_METHOD_RECOVER_INDEX));
+    cmd_def.into()
+}
-- 
2.20.1