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|
// Copyright (C) 2009-2020 Joel Rosdahl and other contributors
//
// See doc/AUTHORS.adoc for a complete list of contributors.
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program; if not, write to the Free Software Foundation, Inc., 51
// Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#include "manifest.hpp"
#include "AtomicFile.hpp"
#include "CacheEntryReader.hpp"
#include "CacheEntryWriter.hpp"
#include "Checksum.hpp"
#include "Config.hpp"
#include "Context.hpp"
#include "File.hpp"
#include "StdMakeUnique.hpp"
#include "ccache.hpp"
#include "hash.hpp"
#include "hashutil.hpp"
#include "logging.hpp"
// Manifest data format
// ====================
//
// Integers are big-endian.
//
// <manifest> ::= <header> <body> <epilogue
// <header> ::= <magic> <version> <compr_type> <compr_level>
// <content_len>
// <magic> ::= 4 bytes ("cCrS")
// <version> ::= uint8_t
// <compr_type> ::= <compr_none> | <compr_zstd>
// <compr_none> ::= 0 (uint8_t)
// <compr_zstd> ::= 1 (uint8_t)
// <compr_level> ::= int8_t
// <content_len> ::= uint64_t ; size of file if stored uncompressed
// <body> ::= <paths> <includes> <results> ; body is potentially
// ; compressed
// <paths> ::= <n_paths> <path_entry>*
// <n_paths> ::= uint32_t
// <path_entry> ::= <path_len> <path>
// <path_len> ::= uint16_t
// <path> ::= path_len bytes
// <includes> ::= <n_includes> <include_entry>*
// <n_includes> ::= uint32_t
// <include_entry> ::= <path_index> <digest> <fsize> <mtime> <ctime>
// <path_index> ::= uint32_t
// <digest> ::= DIGEST_SIZE bytes
// <fsize> ::= uint64_t ; file size
// <mtime> ::= int64_t ; modification time
// <ctime> ::= int64_t ; status change time
// <results> ::= <n_results> <result>*
// <n_results> ::= uint32_t
// <result> ::= <n_indexes> <include_index>* <name>
// <n_indexes> ::= uint32_t
// <include_index> ::= uint32_t
// <name> ::= DIGEST_SIZE bytes
// <epilogue> ::= <checksum>
// <checksum> ::= uint64_t ; XXH64 of content bytes
//
// Sketch of concrete layout:
// <magic> 4 bytes
// <version> 1 byte
// <compr_type> 1 byte
// <compr_level> 1 byte
// <content_len> 8 bytes
// --- [potentially compressed from here] -------------------------------------
// <n_paths> 4 bytes
// <path_len> 2 bytes
// <path> path_len bytes
// ...
// ----------------------------------------------------------------------------
// <n_includes> 4 bytes
// <path_index> 4 bytes
// <digest> DIGEST_SIZE bytes
// <fsize> 8 bytes
// <mtime> 8 bytes
// <ctime> 8 bytes
// ...
// ----------------------------------------------------------------------------
// <n_results> 4 bytes
// <n_indexes> 4 bytes
// <include_index> 4 bytes
// ...
// <name> DIGEST_SIZE bytes
// ...
// checksum 8 bytes
//
//
// Version history
// ===============
//
// 1: Introduced in ccache 3.0. (Files are always compressed with gzip.)
// 2: Introduced in ccache 4.0.
const uint8_t k_manifest_magic[4] = {'c', 'C', 'm', 'F'};
const uint8_t k_manifest_version = 2;
const uint32_t k_max_manifest_entries = 100;
const uint32_t k_max_manifest_file_info_entries = 10000;
namespace {
struct FileInfo
{
// Index to n_files.
uint32_t index;
// Digest of referenced file.
struct digest digest;
// Size of referenced file.
uint64_t fsize;
// mtime of referenced file.
int64_t mtime;
// ctime of referenced file.
int64_t ctime;
};
bool
operator==(const FileInfo& lhs, const FileInfo& rhs)
{
return lhs.index == rhs.index && digests_equal(&lhs.digest, &rhs.digest)
&& lhs.fsize == rhs.fsize && lhs.mtime == rhs.mtime
&& lhs.ctime == rhs.ctime;
}
} // namespace
namespace std {
template<> struct hash<FileInfo>
{
size_t
operator()(const FileInfo& file_info) const
{
static_assert(sizeof(FileInfo) == 48, "unexpected size"); // No padding.
Checksum checksum;
checksum.update(&file_info, sizeof(file_info));
return checksum.digest();
}
};
} // namespace std
struct ResultEntry
{
// Indexes to file_infos.
std::vector<uint32_t> file_info_indexes;
// Name of the result.
struct digest name;
};
struct ManifestData
{
// Referenced include files.
std::vector<std::string> files;
// Information about referenced include files.
std::vector<FileInfo> file_infos;
// Result names plus references to include file infos.
std::vector<ResultEntry> results;
void
add_result_entry(
const struct digest& result_digest,
const std::unordered_map<std::string, digest>& included_files,
time_t time_of_compilation,
bool save_timestamp)
{
std::unordered_map<std::string, uint32_t /*index*/> mf_files;
for (uint32_t i = 0; i < files.size(); ++i) {
mf_files.emplace(files[i], i);
}
std::unordered_map<FileInfo, uint32_t /*index*/> mf_file_infos;
for (uint32_t i = 0; i < file_infos.size(); ++i) {
mf_file_infos.emplace(file_infos[i], i);
}
std::vector<uint32_t> file_info_indexes;
file_info_indexes.reserve(included_files.size());
for (const auto& item : included_files) {
file_info_indexes.push_back(get_file_info_index(item.first,
item.second,
mf_files,
mf_file_infos,
time_of_compilation,
save_timestamp));
}
results.push_back(ResultEntry{std::move(file_info_indexes), result_digest});
}
private:
uint32_t
get_file_info_index(
const std::string& path,
const digest& digest,
const std::unordered_map<std::string, uint32_t>& mf_files,
const std::unordered_map<FileInfo, uint32_t>& mf_file_infos,
time_t time_of_compilation,
bool save_timestamp)
{
struct FileInfo fi;
auto f_it = mf_files.find(path);
if (f_it != mf_files.end()) {
fi.index = f_it->second;
} else {
files.push_back(path);
fi.index = files.size() - 1;
}
fi.digest = digest;
// file_stat.{m,c}time() have a resolution of 1 second, so we can cache the
// file's mtime and ctime only if they're at least one second older than
// time_of_compilation.
//
// file_stat.ctime() may be 0, so we have to check time_of_compilation
// against MAX(mtime, ctime).
//
// ccache only reads mtime/ctime if file_stat_match sloppiness is enabled,
// so mtimes/ctimes are stored as a dummy value (-1) if not enabled. This
// reduces the number of file_info entries for the common case.
auto file_stat = Stat::stat(path, Stat::OnError::log);
if (file_stat) {
if (save_timestamp
&& time_of_compilation
> std::max(file_stat.mtime(), file_stat.ctime())) {
fi.mtime = file_stat.mtime();
fi.ctime = file_stat.ctime();
} else {
fi.mtime = -1;
fi.ctime = -1;
}
fi.fsize = file_stat.size();
} else {
fi.mtime = -1;
fi.ctime = -1;
fi.fsize = 0;
}
auto fi_it = mf_file_infos.find(fi);
if (fi_it != mf_file_infos.end()) {
return fi_it->second;
} else {
file_infos.push_back(fi);
return file_infos.size() - 1;
}
}
};
struct FileStats
{
uint64_t size;
int64_t mtime;
int64_t ctime;
};
static std::unique_ptr<ManifestData>
read_manifest(const std::string& path, FILE* dump_stream = nullptr)
{
File file(path, "rb");
if (!file) {
return {};
}
CacheEntryReader reader(file.get(), k_manifest_magic, k_manifest_version);
if (dump_stream) {
reader.dump_header(dump_stream);
}
auto mf = std::make_unique<ManifestData>();
uint32_t entry_count;
reader.read(entry_count);
for (uint32_t i = 0; i < entry_count; ++i) {
mf->files.emplace_back();
auto& entry = mf->files.back();
uint16_t length;
reader.read(length);
entry.assign(length, 0);
reader.read(&entry[0], length);
}
reader.read(entry_count);
for (uint32_t i = 0; i < entry_count; ++i) {
mf->file_infos.emplace_back();
auto& entry = mf->file_infos.back();
reader.read(entry.index);
reader.read(entry.digest.bytes, DIGEST_SIZE);
reader.read(entry.fsize);
reader.read(entry.mtime);
reader.read(entry.ctime);
}
reader.read(entry_count);
for (uint32_t i = 0; i < entry_count; ++i) {
mf->results.emplace_back();
auto& entry = mf->results.back();
uint32_t file_info_count;
reader.read(file_info_count);
for (uint32_t j = 0; j < file_info_count; ++j) {
uint32_t file_info_index;
reader.read(file_info_index);
entry.file_info_indexes.push_back(file_info_index);
}
reader.read(entry.name.bytes, DIGEST_SIZE);
}
reader.finalize();
return mf;
}
static bool
write_manifest(const Config& config,
const std::string& path,
const ManifestData& mf)
{
uint64_t payload_size = 0;
payload_size += 4; // n_files
for (const auto& file : mf.files) {
payload_size += 2 + file.length();
}
payload_size += 4; // n_file_infos
payload_size += mf.file_infos.size() * (4 + DIGEST_SIZE + 8 + 8 + 8);
payload_size += 4; // n_results
for (const auto& result : mf.results) {
payload_size += 4; // n_file_info_indexes
payload_size += result.file_info_indexes.size() * 4;
payload_size += DIGEST_SIZE;
}
AtomicFile atomic_manifest_file(path, AtomicFile::Mode::binary);
CacheEntryWriter writer(atomic_manifest_file.stream(),
k_manifest_magic,
k_manifest_version,
Compression::type_from_config(config),
Compression::level_from_config(config),
payload_size);
writer.write<uint32_t>(mf.files.size());
for (const auto& file : mf.files) {
writer.write<uint16_t>(file.length());
writer.write(file.data(), file.length());
}
writer.write<uint32_t>(mf.file_infos.size());
for (const auto& file_info : mf.file_infos) {
writer.write<uint32_t>(file_info.index);
writer.write(file_info.digest.bytes, DIGEST_SIZE);
writer.write(file_info.fsize);
writer.write(file_info.mtime);
writer.write(file_info.ctime);
}
writer.write<uint32_t>(mf.results.size());
for (const auto& result : mf.results) {
writer.write<uint32_t>(result.file_info_indexes.size());
for (uint32_t j = 0; j < result.file_info_indexes.size(); ++j) {
writer.write(result.file_info_indexes[j]);
}
writer.write(result.name.bytes, DIGEST_SIZE);
}
writer.finalize();
atomic_manifest_file.commit();
return true;
}
static bool
verify_result(const Context& ctx,
const ManifestData& mf,
const ResultEntry& result,
std::unordered_map<std::string, FileStats>& stated_files,
std::unordered_map<std::string, digest>& hashed_files)
{
for (uint32_t file_info_index : result.file_info_indexes) {
const auto& fi = mf.file_infos[file_info_index];
const auto& path = mf.files[fi.index];
auto stated_files_iter = stated_files.find(path);
if (stated_files_iter == stated_files.end()) {
auto file_stat = Stat::stat(path, Stat::OnError::log);
if (!file_stat) {
return false;
}
FileStats st;
st.size = file_stat.size();
st.mtime = file_stat.mtime();
st.ctime = file_stat.ctime();
stated_files_iter = stated_files.emplace(path, st).first;
}
const FileStats& fs = stated_files_iter->second;
if (fi.fsize != fs.size) {
return false;
}
// Clang stores the mtime of the included files in the precompiled header,
// and will error out if that header is later used without rebuilding.
if ((ctx.guessed_compiler == GuessedCompiler::clang
|| ctx.guessed_compiler == GuessedCompiler::unknown)
&& ctx.args_info.output_is_precompiled_header && fi.mtime != fs.mtime) {
cc_log("Precompiled header includes %s, which has a new mtime",
path.c_str());
return false;
}
if (ctx.config.sloppiness() & SLOPPY_FILE_STAT_MATCHES) {
if (!(ctx.config.sloppiness() & SLOPPY_FILE_STAT_MATCHES_CTIME)) {
if (fi.mtime == fs.mtime && fi.ctime == fs.ctime) {
cc_log("mtime/ctime hit for %s", path.c_str());
continue;
} else {
cc_log("mtime/ctime miss for %s", path.c_str());
}
} else {
if (fi.mtime == fs.mtime) {
cc_log("mtime hit for %s", path.c_str());
continue;
} else {
cc_log("mtime miss for %s", path.c_str());
}
}
}
auto hashed_files_iter = hashed_files.find(path);
if (hashed_files_iter == hashed_files.end()) {
struct hash* hash = hash_init();
int ret = hash_source_code_file(ctx.config, hash, path.c_str());
if (ret & HASH_SOURCE_CODE_ERROR) {
cc_log("Failed hashing %s", path.c_str());
hash_free(hash);
return false;
}
if (ret & HASH_SOURCE_CODE_FOUND_TIME) {
hash_free(hash);
return false;
}
digest actual;
hash_result_as_bytes(hash, &actual);
hash_free(hash);
hashed_files_iter = hashed_files.emplace(path, actual).first;
}
if (!digests_equal(&fi.digest, &hashed_files_iter->second)) {
return false;
}
}
return true;
}
// Try to get the result name from a manifest file. Caller frees. Returns NULL
// on failure.
struct digest*
manifest_get(const Context& ctx, const std::string& path)
{
std::unique_ptr<ManifestData> mf;
try {
mf = read_manifest(path);
if (mf) {
// Update modification timestamp to save files from LRU cleanup.
update_mtime(path.c_str());
} else {
cc_log("No such result file");
return nullptr;
}
} catch (const Error& e) {
cc_log("Error: %s", e.what());
return nullptr;
}
std::unordered_map<std::string, FileStats> stated_files;
std::unordered_map<std::string, digest> hashed_files;
// Check newest result first since it's a bit more likely to match.
struct digest* name = nullptr;
for (uint32_t i = mf->results.size(); i > 0; i--) {
if (verify_result(
ctx, *mf, mf->results[i - 1], stated_files, hashed_files)) {
name = static_cast<digest*>(x_malloc(sizeof(digest)));
*name = mf->results[i - 1].name;
break;
}
}
return name;
}
// Put the result name into a manifest file given a set of included files.
// Returns true on success, otherwise false.
bool
manifest_put(const Config& config,
const std::string& path,
const struct digest& result_name,
const std::unordered_map<std::string, digest>& included_files,
time_t time_of_compilation,
bool save_timestamp)
{
// We don't bother to acquire a lock when writing the manifest to disk. A
// race between two processes will only result in one lost entry, which is
// not a big deal, and it's also very unlikely.
std::unique_ptr<ManifestData> mf;
try {
mf = read_manifest(path);
if (!mf) {
// Manifest file didn't exist.
mf = std::make_unique<ManifestData>();
}
} catch (const Error& e) {
cc_log("Error: %s", e.what());
// Manifest file was corrupt, ignore.
mf = std::make_unique<ManifestData>();
}
if (mf->results.size() > k_max_manifest_entries) {
// Normally, there shouldn't be many result entries in the manifest since
// new entries are added only if an include file has changed but not the
// source file, and you typically change source files more often than
// header files. However, it's certainly possible to imagine cases where
// the manifest will grow large (for instance, a generated header file that
// changes for every build), and this must be taken care of since
// processing an ever growing manifest eventually will take too much time.
// A good way of solving this would be to maintain the result entries in
// LRU order and discarding the old ones. An easy way is to throw away all
// entries when there are too many. Let's do that for now.
cc_log("More than %u entries in manifest file; discarding",
k_max_manifest_entries);
mf = std::make_unique<ManifestData>();
} else if (mf->file_infos.size() > k_max_manifest_file_info_entries) {
// Rarely, FileInfo entries can grow large in pathological cases where
// many included files change, but the main file does not. This also puts
// an upper bound on the number of FileInfo entries.
cc_log("More than %u FileInfo entries in manifest file; discarding",
k_max_manifest_file_info_entries);
mf = std::make_unique<ManifestData>();
}
mf->add_result_entry(
result_name, included_files, time_of_compilation, save_timestamp);
try {
write_manifest(config, path, *mf);
return true;
} catch (const Error& e) {
cc_log("Error: %s", e.what());
return false;
}
}
bool
manifest_dump(const std::string& path, FILE* stream)
{
std::unique_ptr<ManifestData> mf;
try {
mf = read_manifest(path, stream);
} catch (const Error& e) {
fmt::print(stream, "Error: {}\n", e.what());
return false;
}
if (!mf) {
fmt::print(stream, "Error: No such file: {}\n", path);
return false;
}
fmt::print(stream, "File paths ({}):\n", mf->files.size());
for (unsigned i = 0; i < mf->files.size(); ++i) {
fmt::print(stream, " {}: {}\n", i, mf->files[i]);
}
fmt::print(stream, "File infos ({}):\n", mf->file_infos.size());
for (unsigned i = 0; i < mf->file_infos.size(); ++i) {
char digest[DIGEST_STRING_BUFFER_SIZE];
fmt::print(stream, " {}:\n", i);
fmt::print(stream, " Path index: {}\n", mf->file_infos[i].index);
digest_as_string(&mf->file_infos[i].digest, digest);
fmt::print(stream, " Hash: {}\n", digest);
fmt::print(stream, " File size: {}\n", mf->file_infos[i].fsize);
fmt::print(stream, " Mtime: {}\n", mf->file_infos[i].mtime);
fmt::print(stream, " Ctime: {}\n", mf->file_infos[i].ctime);
}
fmt::print(stream, "Results ({}):\n", mf->results.size());
for (unsigned i = 0; i < mf->results.size(); ++i) {
char name[DIGEST_STRING_BUFFER_SIZE];
fmt::print(stream, " {}:\n", i);
fmt::print(stream, " File info indexes:");
for (uint32_t file_info_index : mf->results[i].file_info_indexes) {
fmt::print(stream, " {}", file_info_index);
}
fmt::print(stream, "\n");
digest_as_string(&mf->results[i].name, name);
fmt::print(stream, " Name: {}\n", name);
}
return true;
}
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