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/*
* This source code is released into the public domain.
*/
#include <fcntl.h>
#include <unistd.h>
#include <ucl++.h>
#include "config_error.hh"
#include "config_store.hh"
#include "fileutils.hh"
#include "guard.hh"
namespace {
/*
* The global configuration store, created by config::init() and accessed via
* config::get().
*/
lfjail::config::store *config_store = nullptr;
} // anonymous namespace
namespace lfjail::config {
/*
* Initialise the global config store.
*/
void store::init(context const &ctx) {
std::string config_text;
// Load the configuration text.
auto config_path = ctx.dbdir / "config.ucl";
try {
read_file(config_path, std::back_inserter(config_text));
} catch (io_error const &exc) {
// Ignore ENOENT, it simply means we haven't created the
// config file yet, so default values will be used.
if (exc.error == std::errc::no_such_file_or_directory)
return;
throw;
}
// Parse the UCL.
std::string err;
auto uclconfig = ucl::Ucl::parse(config_text, err);
if (!uclconfig)
throw error("{0}: {1}", config_path, err);
auto const &cfg = get();
for (auto const &uclvalue : uclconfig) {
auto &value = cfg.fetch(uclvalue.key());
switch (uclvalue.type()) {
case UCL_INT:
value.integer(uclvalue.int_value());
break;
case UCL_STRING:
value.string(uclvalue.string_value());
break;
default:
throw error(
"INTERNAL ERROR: unknown value type {0}",
static_cast<int>(uclvalue.type()));
}
}
}
/*
* Get the global config store. We expect init() has already been called.
*/
auto store::get() -> store& {
if (config_store == nullptr)
config_store = new store;
return *config_store;
}
/*
* Register a new value with the config store.
*/
auto store::create(this store &self, value *object) -> void {
auto [it, okay] = self.options.insert(std::pair{object->name, object});
if (!okay)
throw error(
"INTERNAL ERROR: attempt to register duplicate config"
" value '{0}'", object->name);
}
/*
* Fetch an existing value in the config store.
*/
auto store::fetch(this store const &self, std::string_view name)
-> value &
{
if (auto it = self.options.find(name); it != self.options.end())
return *it->second;
throw unknown_setting(name);
}
/*
* Fetch all values in the configuration store.
*/
//NOLINTNEXTLINE(cppcoreguidelines-avoid-reference-coroutine-parameters)
auto store::fetch_all(this store const &self) -> std::generator<value const &>
{
for (auto const &it : self.options)
co_yield *it.second;
}
/*
* Write all config values (except defaults) to disk.
*/
void store::write_all(this store const &self, context const &ctx) {
// The UCL C++ API doesn't seem to support creating new objects
// from scratch, so we use the C API here. We should probably
// provider a better wrapper for this.
auto ucl = ::ucl_object_typed_new(UCL_OBJECT);
auto ucl_guard = guard([ucl] { ::ucl_object_unref(ucl); });
// Add all the options to the UCL object.
for (auto const &option : self.fetch_all()) {
if (option.is_default)
continue;
option.add_to_ucl(ucl);
}
// Dump the UCL object to a string.
auto *ucl_c_text = reinterpret_cast<char *>(
::ucl_object_emit(ucl, UCL_EMIT_CONFIG));
//NOLINTNEXTLINE(cppcoreguidelines-no-malloc)
auto ucl_text_guard = guard([ucl_c_text] { ::free(ucl_c_text); });
std::string ucl_text(ucl_c_text);
// Write the object to a file.
auto config_path = ctx.dbdir / "config.ucl";
try {
safe_write_file(config_path, ucl_text);
} catch (io_error const &exc) {
throw error("{}", exc.what());
}
}
} // namespace lfjail::config
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