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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/ByteBuffer.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/DirIterator.h>
#include <LibCore/File.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
static String read_var(const String& name)
{
StringBuilder builder;
builder.append("/proc/sys/");
builder.append(name);
auto path = builder.to_string();
auto f = Core::File::construct(path);
if (!f->open(Core::IODevice::ReadOnly)) {
fprintf(stderr, "open: %s\n", f->error_string());
exit(1);
}
const auto& b = f->read_all();
if (f->error() < 0) {
fprintf(stderr, "read: %s\n", f->error_string());
exit(1);
}
return String((const char*)b.data(), b.size(), Chomp);
}
static void write_var(const String& name, const String& value)
{
StringBuilder builder;
builder.append("/proc/sys/");
builder.append(name);
auto path = builder.to_string();
auto f = Core::File::construct(path);
if (!f->open(Core::IODevice::WriteOnly)) {
fprintf(stderr, "open: %s\n", f->error_string());
exit(1);
}
f->write(value);
if (f->error() < 0) {
fprintf(stderr, "write: %s\n", f->error_string());
exit(1);
}
}
static int handle_show_all()
{
Core::DirIterator di("/proc/sys", Core::DirIterator::SkipDots);
if (di.has_error()) {
fprintf(stderr, "DirIterator: %s\n", di.error_string());
return 1;
}
while (di.has_next()) {
String variable_name = di.next_path();
printf("%s = %s\n", variable_name.characters(), read_var(variable_name).characters());
}
return 0;
}
static int handle_var(const String& var)
{
String spec(var.characters(), Chomp);
auto parts = spec.split('=');
String variable_name = parts[0];
bool is_write = parts.size() > 1;
if (!is_write) {
printf("%s = %s\n", variable_name.characters(), read_var(variable_name).characters());
return 0;
}
printf("%s = %s", variable_name.characters(), read_var(variable_name).characters());
write_var(variable_name, parts[1]);
printf(" -> %s\n", read_var(variable_name).characters());
return 0;
}
int main(int argc, char** argv)
{
bool show_all = false;
const char* var = nullptr;
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", nullptr, 'a');
args_parser.add_positional_argument(var, "variable[=value]", "variable", Core::ArgsParser::Required::No);
args_parser.parse(argc, argv);
if (var == nullptr) {
// Not supplied; assume `-a`.
show_all = true;
}
if (show_all) {
// Ignore `var`, even if it was supplied. Just like the real procps does.
return handle_show_all();
}
return handle_var(var);
}
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