ladybird/Kernel/Syscalls/kill.cpp
Andrew Kaster dea62fe93c Kernel: Guard the all processes list with a Spinlock rather than a Mutex
There are callers of processes().with or processes().for_each that
require interrupts to be disabled. Taking a Mutexe with interrupts
disabled is a recipe for deadlock, so convert this to a Spinlock.
2021-08-28 20:53:38 +02:00

138 lines
3.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Arch/x86/InterruptDisabler.h>
#include <Kernel/Process.h>
namespace Kernel {
KResult Process::do_kill(Process& process, int signal)
{
// FIXME: Allow sending SIGCONT to everyone in the process group.
// FIXME: Should setuid processes have some special treatment here?
if (!is_superuser() && euid() != process.uid() && uid() != process.uid())
return EPERM;
if (process.is_kernel_process()) {
dbgln("Attempted to send signal {} to kernel process {} ({})", signal, process.name(), process.pid());
return EPERM;
}
if (signal != 0)
return process.send_signal(signal, this);
return KSuccess;
}
KResult Process::do_killpg(ProcessGroupID pgrp, int signal)
{
InterruptDisabler disabler;
VERIFY(pgrp >= 0);
// Send the signal to all processes in the given group.
if (pgrp == 0) {
// Send the signal to our own pgrp.
pgrp = pgid();
}
bool group_was_empty = true;
bool any_succeeded = false;
KResult error = KSuccess;
Process::for_each_in_pgrp(pgrp, [&](auto& process) {
group_was_empty = false;
KResult res = do_kill(process, signal);
if (res.is_success())
any_succeeded = true;
else
error = res;
});
if (group_was_empty)
return ESRCH;
if (any_succeeded)
return KSuccess;
return error;
}
KResult Process::do_killall(int signal)
{
InterruptDisabler disabler;
bool any_succeeded = false;
KResult error = KSuccess;
// Send the signal to all processes we have access to for.
processes().for_each([&](auto& process) {
KResult res = KSuccess;
if (process.pid() == pid())
res = do_killself(signal);
else
res = do_kill(process, signal);
if (res.is_success())
any_succeeded = true;
else
error = res;
});
if (any_succeeded)
return KSuccess;
return error;
}
KResult Process::do_killself(int signal)
{
if (signal == 0)
return KSuccess;
auto current_thread = Thread::current();
if (!current_thread->should_ignore_signal(signal))
current_thread->send_signal(signal, this);
return KSuccess;
}
KResultOr<FlatPtr> Process::sys$kill(pid_t pid_or_pgid, int signal)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
if (pid_or_pgid == pid().value())
REQUIRE_PROMISE(stdio);
else
REQUIRE_PROMISE(proc);
if (signal < 0 || signal >= 32)
return EINVAL;
if (pid_or_pgid < -1) {
if (pid_or_pgid == NumericLimits<i32>::min())
return EINVAL;
return do_killpg(-pid_or_pgid, signal);
}
if (pid_or_pgid == -1)
return do_killall(signal);
if (pid_or_pgid == pid().value()) {
return do_killself(signal);
}
VERIFY(pid_or_pgid >= 0);
auto peer = Process::from_pid(pid_or_pgid);
if (!peer)
return ESRCH;
return do_kill(*peer, signal);
}
KResultOr<FlatPtr> Process::sys$killpg(pid_t pgrp, int signum)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(proc);
if (signum < 1 || signum >= 32)
return EINVAL;
if (pgrp < 0)
return EINVAL;
return do_killpg(pgrp, signum);
}
}