src/bin/proxmox_backup_client/mount.rs: split out mount code

src/bin/proxmox_backup_client/mod.rs

@@ -1,2 +1,4 @@
 mod benchmark;
 pub use benchmark::*;
+mod mount;
+pub use mount::*;

src/bin/proxmox_backup_client/mount.rs

@@ -0,0 +1,197 @@
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::os::unix::io::RawFd;
+use std::path::Path;
+use std::ffi::OsStr;
+
+use anyhow::{bail, format_err, Error};
+use serde_json::Value;
+use tokio::signal::unix::{signal, SignalKind};
+use nix::unistd::{fork, ForkResult, pipe};
+use futures::select;
+use futures::future::FutureExt;
+
+use proxmox::{sortable, identity};
+use proxmox::api::{ApiHandler, ApiMethod, RpcEnvironment, schema::*};
+
+
+use proxmox_backup::tools;
+use proxmox_backup::backup::{
+    load_and_decrypt_key,
+    CryptConfig,
+    IndexFile,
+    BackupDir,
+    BackupGroup,
+    BufferedDynamicReader,
+};
+
+use proxmox_backup::client::*;
+use proxmox::api::cli::*;
+
+use crate::{
+    REPO_URL_SCHEMA,
+    extract_repository_from_value,
+    get_encryption_key_password,
+    complete_pxar_archive_name,
+    complete_group_or_snapshot,
+    complete_repository,
+    record_repository,
+    connect,
+    api_datastore_latest_snapshot,
+    BufferedDynamicReadAt,
+};
+
+#[sortable]
+const API_METHOD_MOUNT: ApiMethod = ApiMethod::new(
+    &ApiHandler::Sync(&mount),
+    &ObjectSchema::new(
+        "Mount pxar archive.",
+        &sorted!([
+            ("snapshot", false, &StringSchema::new("Group/Snapshot path.").schema()),
+            ("archive-name", false, &StringSchema::new("Backup archive name.").schema()),
+            ("target", false, &StringSchema::new("Target directory path.").schema()),
+            ("repository", true, &REPO_URL_SCHEMA),
+            ("keyfile", true, &StringSchema::new("Path to encryption key.").schema()),
+            ("verbose", true, &BooleanSchema::new("Verbose output.").default(false).schema()),
+        ]),
+    )
+);
+
+pub fn mount_cmd_def() -> CliCommand {
+
+    CliCommand::new(&API_METHOD_MOUNT)
+        .arg_param(&["snapshot", "archive-name", "target"])
+        .completion_cb("repository", complete_repository)
+        .completion_cb("snapshot", complete_group_or_snapshot)
+        .completion_cb("archive-name", complete_pxar_archive_name)
+        .completion_cb("target", tools::complete_file_name)
+}
+
+fn mount(
+    param: Value,
+    _info: &ApiMethod,
+    _rpcenv: &mut dyn RpcEnvironment,
+) -> Result<Value, Error> {
+
+    let verbose = param["verbose"].as_bool().unwrap_or(false);
+    if verbose {
+        // This will stay in foreground with debug output enabled as None is
+        // passed for the RawFd.
+        return proxmox_backup::tools::runtime::main(mount_do(param, None));
+    }
+
+    // Process should be deamonized.
+    // Make sure to fork before the async runtime is instantiated to avoid troubles.
+    let pipe = pipe()?;
+    match fork() {
+        Ok(ForkResult::Parent { .. }) => {
+            nix::unistd::close(pipe.1).unwrap();
+            // Blocks the parent process until we are ready to go in the child
+            let _res = nix::unistd::read(pipe.0, &mut [0]).unwrap();
+            Ok(Value::Null)
+        }
+        Ok(ForkResult::Child) => {
+            nix::unistd::close(pipe.0).unwrap();
+            nix::unistd::setsid().unwrap();
+            proxmox_backup::tools::runtime::main(mount_do(param, Some(pipe.1)))
+        }
+        Err(_) => bail!("failed to daemonize process"),
+    }
+}
+
+async fn mount_do(param: Value, pipe: Option<RawFd>) -> Result<Value, Error> {
+    let repo = extract_repository_from_value(&param)?;
+    let archive_name = tools::required_string_param(&param, "archive-name")?;
+    let target = tools::required_string_param(&param, "target")?;
+    let client = connect(repo.host(), repo.user())?;
+
+    record_repository(&repo);
+
+    let path = tools::required_string_param(&param, "snapshot")?;
+    let (backup_type, backup_id, backup_time) = if path.matches('/').count() == 1 {
+        let group: BackupGroup = path.parse()?;
+        api_datastore_latest_snapshot(&client, repo.store(), group).await?
+    } else {
+        let snapshot: BackupDir = path.parse()?;
+        (snapshot.group().backup_type().to_owned(), snapshot.group().backup_id().to_owned(), snapshot.backup_time())
+    };
+
+    let keyfile = param["keyfile"].as_str().map(PathBuf::from);
+    let crypt_config = match keyfile {
+        None => None,
+        Some(path) => {
+            let (key, _) = load_and_decrypt_key(&path, &get_encryption_key_password)?;
+            Some(Arc::new(CryptConfig::new(key)?))
+        }
+    };
+
+    let server_archive_name = if archive_name.ends_with(".pxar") {
+        format!("{}.didx", archive_name)
+    } else {
+        bail!("Can only mount pxar archives.");
+    };
+
+    let client = BackupReader::start(
+        client,
+        crypt_config.clone(),
+        repo.store(),
+        &backup_type,
+        &backup_id,
+        backup_time,
+        true,
+    ).await?;
+
+    let manifest = client.download_manifest().await?;
+
+    if server_archive_name.ends_with(".didx") {
+        let index = client.download_dynamic_index(&manifest, &server_archive_name).await?;
+        let most_used = index.find_most_used_chunks(8);
+        let chunk_reader = RemoteChunkReader::new(client.clone(), crypt_config, most_used);
+        let reader = BufferedDynamicReader::new(index, chunk_reader);
+        let archive_size = reader.archive_size();
+        let reader: proxmox_backup::pxar::fuse::Reader =
+            Arc::new(BufferedDynamicReadAt::new(reader));
+        let decoder = proxmox_backup::pxar::fuse::Accessor::new(reader, archive_size).await?;
+        let options = OsStr::new("ro,default_permissions");
+
+        let session = proxmox_backup::pxar::fuse::Session::mount(
+            decoder,
+            &options,
+            false,
+            Path::new(target),
+        )
+        .map_err(|err| format_err!("pxar mount failed: {}", err))?;
+
+        if let Some(pipe) = pipe {
+            nix::unistd::chdir(Path::new("/")).unwrap();
+            // Finish creation of daemon by redirecting filedescriptors.
+            let nullfd = nix::fcntl::open(
+                "/dev/null",
+                nix::fcntl::OFlag::O_RDWR,
+                nix::sys::stat::Mode::empty(),
+            ).unwrap();
+            nix::unistd::dup2(nullfd, 0).unwrap();
+            nix::unistd::dup2(nullfd, 1).unwrap();
+            nix::unistd::dup2(nullfd, 2).unwrap();
+            if nullfd > 2 {
+                nix::unistd::close(nullfd).unwrap();
+            }
+            // Signal the parent process that we are done with the setup and it can
+            // terminate.
+            nix::unistd::write(pipe, &[0u8])?;
+            nix::unistd::close(pipe).unwrap();
+        }
+
+        let mut interrupt = signal(SignalKind::interrupt())?;
+        select! {
+            res = session.fuse() => res?,
+            _ = interrupt.recv().fuse() => {
+                // exit on interrupted
+            }
+        }
+    } else {
+        bail!("unknown archive file extension (expected .pxar)");
+    }
+
+    Ok(Value::Null)
+}