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//===-- ModuleCache.cpp ---------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "lldb/Target/ModuleCache.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Host/File.h"
#include "lldb/Host/LockFile.h"
#include "lldb/Utility/Log.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include <assert.h>
#include <cstdio>
using namespace lldb;
using namespace lldb_private;
namespace {
const char *kModulesSubdir = ".cache";
const char *kLockDirName = ".lock";
const char *kTempFileName = ".temp";
const char *kTempSymFileName = ".symtemp";
const char *kSymFileExtension = ".sym";
const char *kFSIllegalChars = "\\/:*?\"<>|";
std::string GetEscapedHostname(const char *hostname) {
if (hostname == nullptr)
hostname = "unknown";
std::string result(hostname);
size_t size = result.size();
for (size_t i = 0; i < size; ++i) {
if ((result[i] >= 1 && result[i] <= 31) ||
strchr(kFSIllegalChars, result[i]) != nullptr)
result[i] = '_';
}
return result;
}
class ModuleLock {
private:
FileUP m_file_up;
std::unique_ptr<lldb_private::LockFile> m_lock;
FileSpec m_file_spec;
public:
ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, Status &error);
void Delete();
};
static FileSpec JoinPath(const FileSpec &path1, const char *path2) {
FileSpec result_spec(path1);
result_spec.AppendPathComponent(path2);
return result_spec;
}
static Status MakeDirectory(const FileSpec &dir_path) {
namespace fs = llvm::sys::fs;
return fs::create_directories(dir_path.GetPath(), true, fs::perms::owner_all);
}
FileSpec GetModuleDirectory(const FileSpec &root_dir_spec, const UUID &uuid) {
const auto modules_dir_spec = JoinPath(root_dir_spec, kModulesSubdir);
return JoinPath(modules_dir_spec, uuid.GetAsString().c_str());
}
FileSpec GetSymbolFileSpec(const FileSpec &module_file_spec) {
return FileSpec(module_file_spec.GetPath() + kSymFileExtension);
}
void DeleteExistingModule(const FileSpec &root_dir_spec,
const FileSpec &sysroot_module_path_spec) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES));
UUID module_uuid;
{
auto module_sp =
std::make_shared<Module>(ModuleSpec(sysroot_module_path_spec));
module_uuid = module_sp->GetUUID();
}
if (!module_uuid.IsValid())
return;
Status error;
ModuleLock lock(root_dir_spec, module_uuid, error);
if (error.Fail()) {
LLDB_LOGF(log, "Failed to lock module %s: %s",
module_uuid.GetAsString().c_str(), error.AsCString());
}
namespace fs = llvm::sys::fs;
fs::file_status st;
if (status(sysroot_module_path_spec.GetPath(), st))
return;
if (st.getLinkCount() > 2) // module is referred by other hosts.
return;
const auto module_spec_dir = GetModuleDirectory(root_dir_spec, module_uuid);
llvm::sys::fs::remove_directories(module_spec_dir.GetPath());
lock.Delete();
}
void DecrementRefExistingModule(const FileSpec &root_dir_spec,
const FileSpec &sysroot_module_path_spec) {
// Remove $platform/.cache/$uuid folder if nobody else references it.
DeleteExistingModule(root_dir_spec, sysroot_module_path_spec);
// Remove sysroot link.
llvm::sys::fs::remove(sysroot_module_path_spec.GetPath());
FileSpec symfile_spec = GetSymbolFileSpec(sysroot_module_path_spec);
llvm::sys::fs::remove(symfile_spec.GetPath());
}
Status CreateHostSysRootModuleLink(const FileSpec &root_dir_spec,
const char *hostname,
const FileSpec &platform_module_spec,
const FileSpec &local_module_spec,
bool delete_existing) {
const auto sysroot_module_path_spec =
JoinPath(JoinPath(root_dir_spec, hostname),
platform_module_spec.GetPath().c_str());
if (FileSystem::Instance().Exists(sysroot_module_path_spec)) {
if (!delete_existing)
return Status();
DecrementRefExistingModule(root_dir_spec, sysroot_module_path_spec);
}
const auto error = MakeDirectory(
FileSpec(sysroot_module_path_spec.GetDirectory().AsCString()));
if (error.Fail())
return error;
return llvm::sys::fs::create_hard_link(local_module_spec.GetPath(),
sysroot_module_path_spec.GetPath());
}
} // namespace
ModuleLock::ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid,
Status &error) {
const auto lock_dir_spec = JoinPath(root_dir_spec, kLockDirName);
error = MakeDirectory(lock_dir_spec);
if (error.Fail())
return;
m_file_spec = JoinPath(lock_dir_spec, uuid.GetAsString().c_str());
auto file = FileSystem::Instance().Open(
m_file_spec, File::eOpenOptionWrite | File::eOpenOptionCanCreate |
File::eOpenOptionCloseOnExec);
if (file)
m_file_up = std::move(file.get());
else {
m_file_up.reset();
error = Status(file.takeError());
return;
}
m_lock = std::make_unique<lldb_private::LockFile>(m_file_up->GetDescriptor());
error = m_lock->WriteLock(0, 1);
if (error.Fail())
error.SetErrorStringWithFormat("Failed to lock file: %s",
error.AsCString());
}
void ModuleLock::Delete() {
if (!m_file_up)
return;
m_file_up->Close();
m_file_up.reset();
llvm::sys::fs::remove(m_file_spec.GetPath());
}
/////////////////////////////////////////////////////////////////////////
Status ModuleCache::Put(const FileSpec &root_dir_spec, const char *hostname,
const ModuleSpec &module_spec, const FileSpec &tmp_file,
const FileSpec &target_file) {
const auto module_spec_dir =
GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
const auto module_file_path =
JoinPath(module_spec_dir, target_file.GetFilename().AsCString());
const auto tmp_file_path = tmp_file.GetPath();
const auto err_code =
llvm::sys::fs::rename(tmp_file_path, module_file_path.GetPath());
if (err_code)
return Status("Failed to rename file %s to %s: %s", tmp_file_path.c_str(),
module_file_path.GetPath().c_str(),
err_code.message().c_str());
const auto error = CreateHostSysRootModuleLink(
root_dir_spec, hostname, target_file, module_file_path, true);
if (error.Fail())
return Status("Failed to create link to %s: %s",
module_file_path.GetPath().c_str(), error.AsCString());
return Status();
}
Status ModuleCache::Get(const FileSpec &root_dir_spec, const char *hostname,
const ModuleSpec &module_spec,
ModuleSP &cached_module_sp, bool *did_create_ptr) {
const auto find_it =
m_loaded_modules.find(module_spec.GetUUID().GetAsString());
if (find_it != m_loaded_modules.end()) {
cached_module_sp = (*find_it).second.lock();
if (cached_module_sp)
return Status();
m_loaded_modules.erase(find_it);
}
const auto module_spec_dir =
GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
const auto module_file_path = JoinPath(
module_spec_dir, module_spec.GetFileSpec().GetFilename().AsCString());
if (!FileSystem::Instance().Exists(module_file_path))
return Status("Module %s not found", module_file_path.GetPath().c_str());
if (FileSystem::Instance().GetByteSize(module_file_path) !=
module_spec.GetObjectSize())
return Status("Module %s has invalid file size",
module_file_path.GetPath().c_str());
// We may have already cached module but downloaded from an another host - in
// this case let's create a link to it.
auto error = CreateHostSysRootModuleLink(root_dir_spec, hostname,
module_spec.GetFileSpec(),
module_file_path, false);
if (error.Fail())
return Status("Failed to create link to %s: %s",
module_file_path.GetPath().c_str(), error.AsCString());
auto cached_module_spec(module_spec);
cached_module_spec.GetUUID().Clear(); // Clear UUID since it may contain md5
// content hash instead of real UUID.
cached_module_spec.GetFileSpec() = module_file_path;
cached_module_spec.GetPlatformFileSpec() = module_spec.GetFileSpec();
error = ModuleList::GetSharedModule(cached_module_spec, cached_module_sp,
nullptr, nullptr, did_create_ptr, false);
if (error.Fail())
return error;
FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec());
if (FileSystem::Instance().Exists(symfile_spec))
cached_module_sp->SetSymbolFileFileSpec(symfile_spec);
m_loaded_modules.insert(
std::make_pair(module_spec.GetUUID().GetAsString(), cached_module_sp));
return Status();
}
Status ModuleCache::GetAndPut(const FileSpec &root_dir_spec,
const char *hostname,
const ModuleSpec &module_spec,
const ModuleDownloader &module_downloader,
const SymfileDownloader &symfile_downloader,
lldb::ModuleSP &cached_module_sp,
bool *did_create_ptr) {
const auto module_spec_dir =
GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
auto error = MakeDirectory(module_spec_dir);
if (error.Fail())
return error;
ModuleLock lock(root_dir_spec, module_spec.GetUUID(), error);
if (error.Fail())
return Status("Failed to lock module %s: %s",
module_spec.GetUUID().GetAsString().c_str(),
error.AsCString());
const auto escaped_hostname(GetEscapedHostname(hostname));
// Check local cache for a module.
error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec,
cached_module_sp, did_create_ptr);
if (error.Success())
return error;
const auto tmp_download_file_spec = JoinPath(module_spec_dir, kTempFileName);
error = module_downloader(module_spec, tmp_download_file_spec);
llvm::FileRemover tmp_file_remover(tmp_download_file_spec.GetPath());
if (error.Fail())
return Status("Failed to download module: %s", error.AsCString());
// Put downloaded file into local module cache.
error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec,
tmp_download_file_spec, module_spec.GetFileSpec());
if (error.Fail())
return Status("Failed to put module into cache: %s", error.AsCString());
tmp_file_remover.releaseFile();
error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec,
cached_module_sp, did_create_ptr);
if (error.Fail())
return error;
// Fetching a symbol file for the module
const auto tmp_download_sym_file_spec =
JoinPath(module_spec_dir, kTempSymFileName);
error = symfile_downloader(cached_module_sp, tmp_download_sym_file_spec);
llvm::FileRemover tmp_symfile_remover(tmp_download_sym_file_spec.GetPath());
if (error.Fail())
// Failed to download a symfile but fetching the module was successful. The
// module might contain the necessary symbols and the debugging is also
// possible without a symfile.
return Status();
error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec,
tmp_download_sym_file_spec,
GetSymbolFileSpec(module_spec.GetFileSpec()));
if (error.Fail())
return Status("Failed to put symbol file into cache: %s",
error.AsCString());
tmp_symfile_remover.releaseFile();
FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec());
cached_module_sp->SetSymbolFileFileSpec(symfile_spec);
return Status();
}