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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Process.h>
#include <Kernel/TTY/TTY.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$getsid(pid_t pid)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
if (pid == 0 || pid == this->pid())
return sid().value();
auto peer = Process::from_pid_in_same_jail(pid);
if (!peer)
return ESRCH;
auto peer_sid = peer->sid();
if (sid() != peer_sid)
return EPERM;
return peer_sid.value();
}
ErrorOr<FlatPtr> Process::sys$setsid()
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::proc));
// NOTE: ProcessGroup::create_if_unused_pgid() will fail with EPERM
// if a process group with the same PGID already exists.
auto process_group = TRY(ProcessGroup::create_if_unused_pgid(ProcessGroupID(pid().value())));
auto new_sid = SessionID(pid().value());
auto credentials = this->credentials();
auto new_credentials = TRY(Credentials::create(
credentials->uid(),
credentials->gid(),
credentials->euid(),
credentials->egid(),
credentials->suid(),
credentials->sgid(),
credentials->extra_gids(),
new_sid,
credentials->pgid()));
with_mutable_protected_data([&](auto& protected_data) {
protected_data.tty = nullptr;
protected_data.process_group = move(process_group);
protected_data.credentials = move(new_credentials);
});
return new_sid.value();
}
ErrorOr<FlatPtr> Process::sys$getpgid(pid_t pid)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
if (pid == 0)
return pgid().value();
auto process = Process::from_pid_in_same_jail(pid);
if (!process)
return ESRCH;
return process->pgid().value();
}
ErrorOr<FlatPtr> Process::sys$getpgrp()
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
return pgid().value();
}
SessionID Process::get_sid_from_pgid(ProcessGroupID pgid)
{
// FIXME: This xor sys$setsid() uses the wrong locking mechanism.
SessionID sid { -1 };
MUST(Process::current().for_each_in_pgrp_in_same_jail(pgid, [&](auto& process) -> ErrorOr<void> {
sid = process.sid();
return {};
}));
return sid;
}
ErrorOr<FlatPtr> Process::sys$setpgid(pid_t specified_pid, pid_t specified_pgid)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::proc));
ProcessID pid = specified_pid ? ProcessID(specified_pid) : this->pid();
if (specified_pgid < 0) {
// The value of the pgid argument is less than 0, or is not a value supported by the implementation.
return EINVAL;
}
auto process = Process::from_pid_in_same_jail(pid);
if (!process)
return ESRCH;
if (process != this && process->ppid() != this->pid()) {
// The value of the pid argument does not match the process ID
// of the calling process or of a child process of the calling process.
return ESRCH;
}
if (process->is_session_leader()) {
// The process indicated by the pid argument is a session leader.
return EPERM;
}
if (process->ppid() == this->pid() && process->sid() != sid()) {
// The value of the pid argument matches the process ID of a child
// process of the calling process and the child process is not in
// the same session as the calling process.
return EPERM;
}
ProcessGroupID new_pgid = specified_pgid ? ProcessGroupID(specified_pgid) : process->pid().value();
SessionID current_sid = sid();
SessionID new_sid = get_sid_from_pgid(new_pgid);
if (new_sid != -1 && current_sid != new_sid) {
// Can't move a process between sessions.
return EPERM;
}
if (new_sid == -1 && new_pgid != process->pid().value()) {
// The value of the pgid argument is valid, but is not
// the calling pid, and is not an existing process group.
return EPERM;
}
// FIXME: There are more EPERM conditions to check for here..
auto process_group = TRY(ProcessGroup::find_or_create(new_pgid));
return process->with_mutable_protected_data([&process, &process_group, new_pgid](auto& protected_data) -> ErrorOr<FlatPtr> {
auto credentials = process->credentials();
auto new_credentials = TRY(Credentials::create(
credentials->uid(),
credentials->gid(),
credentials->euid(),
credentials->egid(),
credentials->suid(),
credentials->sgid(),
credentials->extra_gids(),
credentials->sid(),
new_pgid));
protected_data.credentials = move(new_credentials);
protected_data.process_group = move(process_group);
return 0;
});
}
ErrorOr<FlatPtr> Process::sys$get_root_session_id(pid_t force_sid)
{
TRY(require_promise(Pledge::stdio));
pid_t sid = (force_sid == -1) ? this->sid().value() : force_sid;
if (sid == 0)
return 0;
while (true) {
auto sid_process = Process::from_pid_in_same_jail(sid);
if (!sid_process)
return ESRCH;
auto parent_pid = sid_process->ppid().value();
auto parent_process = Process::from_pid_in_same_jail(parent_pid);
if (!parent_process)
return ESRCH;
pid_t parent_sid = parent_process->sid().value();
if (parent_sid == 0)
break;
sid = parent_sid;
}
return sid;
}
}
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