ladybird/Kernel/Syscalls/setpgid.cpp
Brian Gianforcaro bb91bed576 Kernel: Make ProcessGroup::find_or_create API OOM safe
Make ProcessGroup::find_or_create & ProcessGroup::create OOM safe, by
moving to adopt_ref_if_nonnull.
2021-05-20 08:10:07 +02:00

125 lines
3.8 KiB
C++

/*
* 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 {
KResultOr<pid_t> Process::sys$getsid(pid_t pid)
{
REQUIRE_PROMISE(proc);
if (pid == 0)
return sid().value();
ScopedSpinLock lock(g_processes_lock);
auto process = Process::from_pid(pid);
if (!process)
return ESRCH;
if (sid() != process->sid())
return EPERM;
return process->sid().value();
}
KResultOr<pid_t> Process::sys$setsid()
{
REQUIRE_PROMISE(proc);
InterruptDisabler disabler;
bool found_process_with_same_pgid_as_my_pid = false;
Process::for_each_in_pgrp(pid().value(), [&](auto&) {
found_process_with_same_pgid_as_my_pid = true;
return IterationDecision::Break;
});
if (found_process_with_same_pgid_as_my_pid)
return EPERM;
// Create a new Session and a new ProcessGroup.
m_pg = ProcessGroup::create(ProcessGroupID(pid().value()));
m_tty = nullptr;
ProtectedDataMutationScope scope { *this };
m_sid = pid().value();
return sid().value();
}
KResultOr<pid_t> Process::sys$getpgid(pid_t pid)
{
REQUIRE_PROMISE(proc);
if (pid == 0)
return pgid().value();
ScopedSpinLock lock(g_processes_lock); // FIXME: Use a ProcessHandle
auto process = Process::from_pid(pid);
if (!process)
return ESRCH;
return process->pgid().value();
}
KResultOr<pid_t> Process::sys$getpgrp()
{
REQUIRE_PROMISE(stdio);
return pgid().value();
}
SessionID Process::get_sid_from_pgid(ProcessGroupID pgid)
{
// FIXME: This xor sys$setsid() uses the wrong locking mechanism.
ScopedSpinLock lock(g_processes_lock);
SessionID sid { -1 };
Process::for_each_in_pgrp(pgid, [&](auto& process) {
sid = process.sid();
return IterationDecision::Break;
});
return sid;
}
KResultOr<int> Process::sys$setpgid(pid_t specified_pid, pid_t specified_pgid)
{
REQUIRE_PROMISE(proc);
ScopedSpinLock lock(g_processes_lock); // FIXME: Use a ProcessHandle
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(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..
process->m_pg = ProcessGroup::find_or_create(new_pgid);
if (!process->m_pg) {
return ENOMEM;
}
return 0;
}
}