blob: b783e39dfb92d3ce3ea8176ad43fe0b5927ebf7c [file] [log] [blame]
// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <lib/async-loop/cpp/loop.h>
#include <lib/async/dispatcher.h>
#include <lib/zx/status.h>
#include <lib/zx/vmo.h>
#include <memory>
#include <fbl/unique_fd.h>
#include "src/lib/loader_service/loader_service.h"
#include "src/storage/fshost/fshost-boot-args.h"
namespace fshost {
// We bootstrap pkgfs from blobfs by using a custom loader service. This bootstrap is necessary
// because pkgfs itself is what provides "symbolic filename to blobfs merkleroot resolution" for the
// rest of the system.
// Kernel command line arguments with the prefix "zircon.system.pkgfs.file." define the
// file-to-merkleroot mapping that this loader service uses. For example, when the loader service
// receives a LoadObject("") request, it looks for a kernel command line argument with key
// "zircon.system.pkgfs.file.lib/". If such a key exists, its value is treated as a blobfs
// merkleroot and used to load the file from blobfs.
class PkgfsLoaderService : public loader::LoaderServiceBase {
static std::shared_ptr<PkgfsLoaderService> Create(fbl::unique_fd blob_dir,
std::shared_ptr<FshostBootArgs> boot_args);
zx::status<zx::vmo> LoadPkgfsFile(std::string path);
PkgfsLoaderService(std::unique_ptr<async::Loop> loop, fbl::unique_fd blob_dir,
std::shared_ptr<FshostBootArgs> boot_args)
: LoaderServiceBase(loop->dispatcher(), "pkgfs"),
boot_args_(boot_args) {}
virtual zx::status<zx::vmo> LoadObjectImpl(std::string path) override;
zx::status<zx::vmo> LoadBlob(std::string merkleroot);
// This loader automatically creates and owns its own async::Loop to match historical behavior. If
// fshost's threading model is cleaned up then PkgfsLoaderService could be changed to just accept
// an async_dispatcher_t* for an existing loop.
// Also, this is wrapped in unique_ptr purely because async::Loop has a deleted move constructor.
std::unique_ptr<async::Loop> loop_;
// PkgfsLoaderService's lifetime is tied to the pkgfs process because open connections keep the
// loader alive (see LoaderServiceBase), so we take care to hold onto only owned state. (weak_ptr
// would be fine too, just no raw pointers.)
fbl::unique_fd blob_dir_;
std::shared_ptr<FshostBootArgs> boot_args_;
} // namespace fshost