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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Alex Major
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/ArgsParser.h>
#include <LibCore/DirIterator.h>
#include <LibCore/File.h>
#include <LibMain/Main.h>
static bool s_set_variable = false;
static String get_variable(StringView name)
{
auto path = String::formatted("/sys/kernel/variables/{}", name);
auto file = Core::File::construct(path);
if (!file->open(Core::OpenMode::ReadOnly)) {
warnln("Failed to open {}: {}", path, file->error_string());
return {};
}
auto buffer = file->read_all();
if (file->error() < 0) {
warnln("Failed to read {}: {}", path, file->error_string());
return {};
}
return { (char const*)buffer.data(), buffer.size(), Chomp };
}
static bool read_variable(StringView name)
{
auto value = get_variable(name);
if (value.is_null())
return false;
outln("{} = {}", name, value);
return true;
}
static bool write_variable(StringView name, StringView value)
{
auto old_value = get_variable(name);
if (old_value.is_null())
return false;
auto path = String::formatted("/sys/kernel/variables/{}", name);
auto file = Core::File::construct(path);
if (!file->open(Core::OpenMode::WriteOnly)) {
warnln("Failed to open {}: {}", path, file->error_string());
return false;
}
if (!file->write(value)) {
warnln("Failed to write {}: {}", path, file->error_string());
return false;
}
outln("{}: {} -> {}", name, old_value, value);
return true;
}
static int handle_variables(Vector<StringView> const& variables)
{
bool success = false;
for (auto const& variable : variables) {
auto maybe_index = variable.find('=');
if (!maybe_index.has_value()) {
success = read_variable(variable);
continue;
}
auto equal_index = maybe_index.release_value();
auto name = variable.substring_view(0, equal_index);
auto value = variable.substring_view(equal_index + 1, variable.length() - equal_index - 1);
if (name.is_empty())
warnln("Malformed setting '{}'", variable);
else if (!s_set_variable)
warnln("Must specify '-w' to set variables");
else
success = write_variable(name, value);
}
return success ? 0 : 1;
}
static int handle_show_all()
{
Core::DirIterator di("/sys/kernel/variables", Core::DirIterator::SkipDots);
if (di.has_error()) {
outln("DirIterator: {}", di.error_string());
return 1;
}
bool success = false;
while (di.has_next()) {
auto name = di.next_path();
success = read_variable(name);
}
return success ? 0 : 1;
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
bool show_all = false;
Vector<StringView> variables;
Core::ArgsParser args_parser;
args_parser.set_general_help("Show or modify system-internal values. This requires root, and can crash your system.");
args_parser.add_option(show_all, "Show all variables", "all", 'a');
args_parser.add_option(s_set_variable, "Set variables", "write", 'w');
args_parser.add_positional_argument(variables, "variable[=value]", "variables", Core::ArgsParser::Required::No);
args_parser.parse(arguments);
if (!show_all && variables.is_empty()) {
args_parser.print_usage(stdout, arguments.argv[0]);
return 1;
}
if (show_all) {
// Ignore `variables`, even if they are supplied. Just like the real procps does.
return handle_show_all();
}
return handle_variables(variables);
}
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