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/* -*- indent-tabs-mode: nil -*- */
#include "log/file_storage.h"
#include <dirent.h>
#include <errno.h>
#include <glog/logging.h>
#include <sys/stat.h>
#include <unistd.h>
#include <cstdlib>
#include <set>
#include <string>
#include "log/filesystem_ops.h"
#include "util/util.h"
using cert_trans::BasicFilesystemOps;
using cert_trans::FilesystemOps;
using std::string;
namespace cert_trans {
FileStorage::FileStorage(const string& file_base, int storage_depth)
: storage_dir_(file_base + "/storage"),
tmp_dir_(file_base + "/tmp"),
tmp_file_template_(tmp_dir_ + "/tmpXXXXXX"),
storage_depth_(storage_depth),
file_op_(new BasicFilesystemOps()) {
CHECK_GE(storage_depth_, 0);
CreateMissingDirectory(storage_dir_);
CreateMissingDirectory(tmp_dir_);
}
FileStorage::FileStorage(const string& file_base, int storage_depth,
FilesystemOps* file_op)
: storage_dir_(file_base + "/storage"),
tmp_dir_(file_base + "/tmp"),
tmp_file_template_(tmp_dir_ + "/tmpXXXXXX"),
storage_depth_(storage_depth),
file_op_(CHECK_NOTNULL(file_op)) {
CHECK_GE(storage_depth_, 0);
CreateMissingDirectory(storage_dir_);
CreateMissingDirectory(tmp_dir_);
}
FileStorage::~FileStorage() {
// Needs to be where FilesystemOps is visible.
}
std::set<string> FileStorage::Scan() const {
std::set<string> storage_keys;
ScanDir(storage_dir_, storage_depth_, &storage_keys);
return storage_keys;
}
util::Status FileStorage::CreateEntry(const string& key, const string& data) {
if (LookupEntry(key, NULL).ok()) {
return util::Status(util::error::ALREADY_EXISTS,
"entry already exists: " + key);
}
WriteStorageEntry(key, data);
return util::Status::OK;
}
util::Status FileStorage::UpdateEntry(const string& key, const string& data) {
if (!LookupEntry(key, NULL).ok()) {
return util::Status(util::error::NOT_FOUND,
"tried to update non-existent entry: " + key);
}
WriteStorageEntry(key, data);
return util::Status::OK;
}
util::Status FileStorage::LookupEntry(const string& key,
string* result) const {
string data_file = StoragePath(key);
if (!FileExists(data_file)) {
return util::Status(util::error::NOT_FOUND, "entry not found: " + key);
}
if (result) {
CHECK(util::ReadBinaryFile(data_file, result));
}
return util::Status::OK;
}
string FileStorage::StoragePathBasename(const string& hex) const {
if (hex.length() <= static_cast<uint>(storage_depth_))
return "-";
return hex.substr(storage_depth_);
}
string FileStorage::StoragePathComponent(const string& hex, int n) const {
CHECK_GE(n, 0);
CHECK_LT(n, storage_depth_);
if (static_cast<uint>(n) >= hex.length())
return "-";
return string(1, hex[n]);
}
string FileStorage::StoragePath(const string& key) const {
string hex = util::HexString(key);
string dirname = storage_dir_ + "/";
for (int n = 0; n < storage_depth_; ++n)
dirname += StoragePathComponent(hex, n) + "/";
return dirname + StoragePathBasename(hex);
}
string FileStorage::StorageKey(const string& storage_path) const {
CHECK_EQ(storage_path.substr(0, storage_dir_.size()), storage_dir_);
string key_path = storage_path.substr(storage_dir_.size() + 1);
string hex_key;
for (int n = 0; n < storage_depth_; ++n) {
char hex_char = key_path[2 * n];
if (hex_char == '-')
return util::BinaryString(hex_key);
hex_key.push_back(hex_char);
}
string basename = key_path.substr(2 * storage_depth_);
if (basename != "-")
hex_key.append(basename);
return util::BinaryString(hex_key);
}
void FileStorage::WriteStorageEntry(const string& key, const string& data) {
string hex = util::HexString(key);
// Make the intermediate directories, if needed.
// TODO(ekasper): we can skip this if we know we're updating.
string dir = storage_dir_;
for (int n = 0; n < storage_depth_; ++n) {
dir += "/" + StoragePathComponent(hex, n);
CreateMissingDirectory(dir);
}
// == StoragePath(key)
string filename = dir + "/" + StoragePathBasename(hex);
AtomicWriteBinaryFile(filename, data);
}
void FileStorage::ScanFiles(const string& dir_path,
std::set<string>* keys) const {
DIR* dir = CHECK_NOTNULL(opendir(dir_path.c_str()));
struct dirent* entry;
while ((entry = readdir(dir)) != NULL) {
if (entry->d_name[0] == '.')
continue;
keys->insert(StorageKey(dir_path + "/" + entry->d_name));
}
closedir(dir);
}
void FileStorage::ScanDir(const string& dir_path, int depth,
std::set<string>* keys) const {
CHECK_GE(depth, 0);
if (depth > 0) {
// Parse subdirectories. (TODO: make opendir part of filesystemop).
DIR* dir = CHECK_NOTNULL(opendir(dir_path.c_str()));
struct dirent* entry;
std::set<string> result;
while ((entry = readdir(dir)) != NULL) {
if (entry->d_name[0] == '.')
continue;
ScanDir(dir_path + "/" + entry->d_name, depth - 1, keys);
}
closedir(dir);
} else {
// depth == 0; parse files.
ScanFiles(dir_path, keys);
}
}
bool FileStorage::FileExists(const string& file_path) const {
if (file_op_->access(file_path, F_OK) == 0)
return true;
CHECK_EQ(errno, ENOENT);
return false;
}
void FileStorage::AtomicWriteBinaryFile(const string& file_path,
const string& data) {
const string tmp_file(
util::WriteTemporaryBinaryFile(tmp_file_template_, data));
CHECK(!tmp_file.empty());
CHECK_EQ(file_op_->rename(tmp_file, file_path), 0);
}
void FileStorage::CreateMissingDirectory(const string& dir_path) {
if (file_op_->mkdir(dir_path, 0700) != 0) {
CHECK_EQ(errno, EEXIST);
}
}
} // namespace cert_trans
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