ladybird/Userland/Utilities/utmpupdate.cpp
2021-05-17 18:14:05 +01:00

102 lines
2.6 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/ByteBuffer.h>
#include <AK/JsonObject.h>
#include <AK/JsonValue.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/DateTime.h>
#include <LibCore/File.h>
#include <unistd.h>
int main(int argc, char** argv)
{
if (pledge("stdio wpath cpath", nullptr) < 0) {
perror("pledge");
return 1;
}
if (unveil("/var/run/utmp", "rwc") < 0) {
perror("unveil");
return 1;
}
unveil(nullptr, nullptr);
pid_t pid = 0;
bool flag_create = false;
bool flag_delete = false;
const char* tty_name = nullptr;
const char* from = nullptr;
Core::ArgsParser args_parser;
args_parser.add_option(flag_create, "Create entry", "create", 'c');
args_parser.add_option(flag_delete, "Delete entry", "delete", 'd');
args_parser.add_option(pid, "PID", "PID", 'p', "PID");
args_parser.add_option(from, "From", "from", 'f', "From");
args_parser.add_positional_argument(tty_name, "TTY name", "tty");
args_parser.parse(argc, argv);
if (flag_create && flag_delete) {
warnln("-c and -d are mutually exclusive");
return 1;
}
dbgln("Updating utmp from UID={} GID={} EGID={} PID={}", getuid(), getgid(), getegid(), pid);
auto file_or_error = Core::File::open("/var/run/utmp", Core::OpenMode::ReadWrite);
if (file_or_error.is_error()) {
dbgln("Error: {}", file_or_error.error());
return 1;
}
auto& file = *file_or_error.value();
auto file_contents = file.read_all();
auto previous_json = JsonValue::from_string(file_contents);
JsonObject json;
if (!file_contents.is_empty()) {
if (!previous_json.has_value() || !previous_json.value().is_object()) {
dbgln("Error: Could not parse JSON");
} else {
json = previous_json.value().as_object();
}
}
if (flag_create) {
JsonObject entry;
entry.set("pid", pid);
entry.set("uid", getuid());
entry.set("from", from);
entry.set("login_at", time(nullptr));
json.set(tty_name, move(entry));
} else {
VERIFY(flag_delete);
dbgln("Removing {} from utmp", tty_name);
json.remove(tty_name);
}
if (!file.seek(0)) {
dbgln("Seek failed");
return 1;
}
if (!file.truncate(0)) {
dbgln("Truncation failed");
return 1;
}
if (!file.write(json.to_string())) {
dbgln("Write failed");
return 1;
}
return 0;
}