ladybird/Kernel/Process.cpp
Luke Wilde 1682b0b6d8 Kernel: Remove big lock from sys$set_coredump_metadata
The only requirement for this syscall is to make
Process::m_coredump_properties SpinlockProtected.
2022-04-09 21:51:16 +02:00

934 lines
31 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Singleton.h>
#include <AK/StdLibExtras.h>
#include <AK/Time.h>
#include <AK/Types.h>
#include <Kernel/API/Syscall.h>
#include <Kernel/Arch/x86/InterruptDisabler.h>
#include <Kernel/Coredump.h>
#include <Kernel/Debug.h>
#include <Kernel/Devices/DeviceManagement.h>
#ifdef ENABLE_KERNEL_COVERAGE_COLLECTION
# include <Kernel/Devices/KCOVDevice.h>
#endif
#include <Kernel/API/POSIX/errno.h>
#include <Kernel/Devices/NullDevice.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/KSyms.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <Kernel/Memory/PageDirectory.h>
#include <Kernel/Memory/SharedInodeVMObject.h>
#include <Kernel/Panic.h>
#include <Kernel/PerformanceEventBuffer.h>
#include <Kernel/PerformanceManager.h>
#include <Kernel/Process.h>
#include <Kernel/Scheduler.h>
#include <Kernel/Sections.h>
#include <Kernel/StdLib.h>
#include <Kernel/TTY/TTY.h>
#include <Kernel/Thread.h>
#include <Kernel/ThreadTracer.h>
#include <Kernel/TimerQueue.h>
#include <LibC/limits.h>
namespace Kernel {
static void create_signal_trampoline();
extern ProcessID g_init_pid;
RecursiveSpinlock g_profiling_lock;
static Atomic<pid_t> next_pid;
static Singleton<SpinlockProtected<Process::List>> s_all_instances;
READONLY_AFTER_INIT Memory::Region* g_signal_trampoline_region;
static Singleton<MutexProtected<OwnPtr<KString>>> s_hostname;
MutexProtected<OwnPtr<KString>>& hostname()
{
return *s_hostname;
}
SpinlockProtected<Process::List>& Process::all_instances()
{
return *s_all_instances;
}
ProcessID Process::allocate_pid()
{
// Overflow is UB, and negative PIDs wreck havoc.
// TODO: Handle PID overflow
// For example: Use an Atomic<u32>, mask the most significant bit,
// retry if PID is already taken as a PID, taken as a TID,
// takes as a PGID, taken as a SID, or zero.
return next_pid.fetch_add(1, AK::MemoryOrder::memory_order_acq_rel);
}
UNMAP_AFTER_INIT void Process::initialize()
{
next_pid.store(0, AK::MemoryOrder::memory_order_release);
// Note: This is called before scheduling is initialized, and before APs are booted.
// So we can "safely" bypass the lock here.
reinterpret_cast<OwnPtr<KString>&>(hostname()) = KString::must_create("courage"sv);
create_signal_trampoline();
}
bool Process::in_group(GroupID gid) const
{
return this->gid() == gid || extra_gids().contains_slow(gid);
}
void Process::kill_threads_except_self()
{
InterruptDisabler disabler;
if (thread_count() <= 1)
return;
auto* current_thread = Thread::current();
for_each_thread([&](Thread& thread) {
if (&thread == current_thread)
return;
if (auto state = thread.state(); state == Thread::State::Dead
|| state == Thread::State::Dying)
return;
// We need to detach this thread in case it hasn't been joined
thread.detach();
thread.set_should_die();
});
u32 dropped_lock_count = 0;
if (big_lock().force_unlock_exclusive_if_locked(dropped_lock_count) != LockMode::Unlocked)
dbgln("Process {} big lock had {} locks", *this, dropped_lock_count);
}
void Process::kill_all_threads()
{
for_each_thread([&](Thread& thread) {
// We need to detach this thread in case it hasn't been joined
thread.detach();
thread.set_should_die();
});
}
void Process::register_new(Process& process)
{
// Note: this is essentially the same like process->ref()
RefPtr<Process> new_process = process;
all_instances().with([&](auto& list) {
list.prepend(process);
});
}
ErrorOr<NonnullRefPtr<Process>> Process::try_create_user_process(RefPtr<Thread>& first_thread, StringView path, UserID uid, GroupID gid, NonnullOwnPtrVector<KString> arguments, NonnullOwnPtrVector<KString> environment, TTY* tty)
{
auto parts = path.split_view('/');
if (arguments.is_empty()) {
auto last_part = TRY(KString::try_create(parts.last()));
TRY(arguments.try_append(move(last_part)));
}
auto path_string = TRY(KString::try_create(path));
auto name = TRY(KString::try_create(parts.last()));
auto process = TRY(Process::try_create(first_thread, move(name), uid, gid, ProcessID(0), false, VirtualFileSystem::the().root_custody(), nullptr, tty));
TRY(process->m_fds.with_exclusive([&](auto& fds) -> ErrorOr<void> {
TRY(fds.try_resize(Process::OpenFileDescriptions::max_open()));
auto& device_to_use_as_tty = tty ? (CharacterDevice&)*tty : DeviceManagement::the().null_device();
auto description = TRY(device_to_use_as_tty.open(O_RDWR));
auto setup_description = [&](int fd) {
fds.m_fds_metadatas[fd].allocate();
fds[fd].set(*description);
};
setup_description(0);
setup_description(1);
setup_description(2);
return {};
}));
Thread* new_main_thread = nullptr;
u32 prev_flags = 0;
if (auto result = process->exec(move(path_string), move(arguments), move(environment), new_main_thread, prev_flags); result.is_error()) {
dbgln("Failed to exec {}: {}", path, result.error());
first_thread = nullptr;
return result.release_error();
}
register_new(*process);
// NOTE: All user processes have a leaked ref on them. It's balanced by Thread::WaitBlockerSet::finalize().
process->ref();
{
SpinlockLocker lock(g_scheduler_lock);
new_main_thread->set_state(Thread::State::Runnable);
}
return process;
}
RefPtr<Process> Process::create_kernel_process(RefPtr<Thread>& first_thread, NonnullOwnPtr<KString> name, void (*entry)(void*), void* entry_data, u32 affinity, RegisterProcess do_register)
{
auto process_or_error = Process::try_create(first_thread, move(name), UserID(0), GroupID(0), ProcessID(0), true);
if (process_or_error.is_error())
return {};
auto process = process_or_error.release_value();
first_thread->regs().set_ip((FlatPtr)entry);
#if ARCH(I386)
first_thread->regs().esp = FlatPtr(entry_data); // entry function argument is expected to be in regs.esp
#else
first_thread->regs().rdi = FlatPtr(entry_data); // entry function argument is expected to be in regs.rdi
#endif
if (do_register == RegisterProcess::Yes)
register_new(*process);
SpinlockLocker lock(g_scheduler_lock);
first_thread->set_affinity(affinity);
first_thread->set_state(Thread::State::Runnable);
return process;
}
void Process::protect_data()
{
m_protected_data_refs.unref([&]() {
MM.set_page_writable_direct(VirtualAddress { &this->m_protected_values }, false);
});
}
void Process::unprotect_data()
{
m_protected_data_refs.ref([&]() {
MM.set_page_writable_direct(VirtualAddress { &this->m_protected_values }, true);
});
}
ErrorOr<NonnullRefPtr<Process>> Process::try_create(RefPtr<Thread>& first_thread, NonnullOwnPtr<KString> name, UserID uid, GroupID gid, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, TTY* tty, Process* fork_parent)
{
auto space = TRY(Memory::AddressSpace::try_create(fork_parent ? &fork_parent->address_space() : nullptr));
auto unveil_tree = UnveilNode { TRY(KString::try_create("/"sv)), UnveilMetadata(TRY(KString::try_create("/"sv))) };
auto process = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Process(move(name), uid, gid, ppid, is_kernel_process, move(current_directory), move(executable), tty, move(unveil_tree))));
TRY(process->attach_resources(move(space), first_thread, fork_parent));
return process;
}
Process::Process(NonnullOwnPtr<KString> name, UserID uid, GroupID gid, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, TTY* tty, UnveilNode unveil_tree)
: m_name(move(name))
, m_is_kernel_process(is_kernel_process)
, m_executable(move(executable))
, m_current_directory(move(current_directory))
, m_tty(tty)
, m_unveil_data(move(unveil_tree))
, m_wait_blocker_set(*this)
{
// Ensure that we protect the process data when exiting the constructor.
ProtectedDataMutationScope scope { *this };
m_protected_values.pid = allocate_pid();
m_protected_values.ppid = ppid;
m_protected_values.uid = uid;
m_protected_values.gid = gid;
m_protected_values.euid = uid;
m_protected_values.egid = gid;
m_protected_values.suid = uid;
m_protected_values.sgid = gid;
dbgln_if(PROCESS_DEBUG, "Created new process {}({})", m_name, this->pid().value());
}
ErrorOr<void> Process::attach_resources(NonnullOwnPtr<Memory::AddressSpace>&& preallocated_space, RefPtr<Thread>& first_thread, Process* fork_parent)
{
m_space = move(preallocated_space);
auto create_first_thread = [&] {
if (fork_parent) {
// NOTE: fork() doesn't clone all threads; the thread that called fork() becomes the only thread in the new process.
return Thread::current()->try_clone(*this);
}
// NOTE: This non-forked code path is only taken when the kernel creates a process "manually" (at boot.)
return Thread::try_create(*this);
};
first_thread = TRY(create_first_thread());
if (!fork_parent) {
// FIXME: Figure out if this is really necessary.
first_thread->detach();
}
auto weak_ptr = TRY(this->try_make_weak_ptr());
m_procfs_traits = TRY(ProcessProcFSTraits::try_create({}, move(weak_ptr)));
return {};
}
Process::~Process()
{
unprotect_data();
VERIFY(thread_count() == 0); // all threads should have been finalized
VERIFY(!m_alarm_timer);
PerformanceManager::add_process_exit_event(*this);
}
// Make sure the compiler doesn't "optimize away" this function:
extern void signal_trampoline_dummy() __attribute__((used));
void signal_trampoline_dummy()
{
#if ARCH(I386)
// The trampoline preserves the current eax, pushes the signal code and
// then calls the signal handler. We do this because, when interrupting a
// blocking syscall, that syscall may return some special error code in eax;
// This error code would likely be overwritten by the signal handler, so it's
// necessary to preserve it here.
constexpr static auto offset_to_first_register_slot = sizeof(__ucontext) + sizeof(siginfo) + sizeof(FPUState) + 4 * sizeof(FlatPtr);
asm(
".intel_syntax noprefix\n"
".globl asm_signal_trampoline\n"
"asm_signal_trampoline:\n"
// stack state: 0, ucontext, signal_info, (alignment = 16), fpu_state (alignment = 16), 0, ucontext*, siginfo*, signal, (alignment = 16), handler
// Pop the handler into ecx
"pop ecx\n" // save handler
// we have to save eax 'cause it might be the return value from a syscall
"mov [esp+%P1], eax\n"
// Note that the stack is currently aligned to 16 bytes as we popped the extra entries above.
// and it's already setup to call the handler with the expected values on the stack.
// call the signal handler
"call ecx\n"
// drop the 4 arguments
"add esp, 16\n"
// Current stack state is just saved_eax, ucontext, signal_info, fpu_state?.
// syscall SC_sigreturn
"mov eax, %P0\n"
"int 0x82\n"
".globl asm_signal_trampoline_end\n"
"asm_signal_trampoline_end:\n"
".att_syntax"
:
: "i"(Syscall::SC_sigreturn),
"i"(offset_to_first_register_slot));
#elif ARCH(X86_64)
// The trampoline preserves the current rax, pushes the signal code and
// then calls the signal handler. We do this because, when interrupting a
// blocking syscall, that syscall may return some special error code in eax;
// This error code would likely be overwritten by the signal handler, so it's
// necessary to preserve it here.
constexpr static auto offset_to_first_register_slot = sizeof(__ucontext) + sizeof(siginfo) + sizeof(FPUState) + 3 * sizeof(FlatPtr);
asm(
".intel_syntax noprefix\n"
".globl asm_signal_trampoline\n"
"asm_signal_trampoline:\n"
// stack state: 0, ucontext, signal_info (alignment = 16), fpu_state (alignment = 16), ucontext*, siginfo*, signal, handler
// Pop the handler into rcx
"pop rcx\n" // save handler
// we have to save rax 'cause it might be the return value from a syscall
"mov [rsp+%P1], rax\n"
// pop signal number into rdi (first param)
"pop rdi\n"
// pop siginfo* into rsi (second param)
"pop rsi\n"
// pop ucontext* into rdx (third param)
"pop rdx\n"
// Note that the stack is currently aligned to 16 bytes as we popped the extra entries above.
// call the signal handler
"call rcx\n"
// Current stack state is just saved_rax, ucontext, signal_info, fpu_state.
// syscall SC_sigreturn
"mov rax, %P0\n"
"int 0x82\n"
".globl asm_signal_trampoline_end\n"
"asm_signal_trampoline_end:\n"
".att_syntax"
:
: "i"(Syscall::SC_sigreturn),
"i"(offset_to_first_register_slot));
#endif
}
extern "C" char const asm_signal_trampoline[];
extern "C" char const asm_signal_trampoline_end[];
void create_signal_trampoline()
{
// NOTE: We leak this region.
g_signal_trampoline_region = MM.allocate_kernel_region(PAGE_SIZE, "Signal trampolines", Memory::Region::Access::ReadWrite).release_value().leak_ptr();
g_signal_trampoline_region->set_syscall_region(true);
size_t trampoline_size = asm_signal_trampoline_end - asm_signal_trampoline;
u8* code_ptr = (u8*)g_signal_trampoline_region->vaddr().as_ptr();
memcpy(code_ptr, asm_signal_trampoline, trampoline_size);
g_signal_trampoline_region->set_writable(false);
g_signal_trampoline_region->remap();
}
void Process::crash(int signal, FlatPtr ip, bool out_of_memory)
{
VERIFY(!is_dead());
VERIFY(&Process::current() == this);
if (out_of_memory) {
dbgln("\033[31;1mOut of memory\033[m, killing: {}", *this);
} else {
if (ip >= kernel_load_base && g_kernel_symbols_available) {
auto const* symbol = symbolicate_kernel_address(ip);
dbgln("\033[31;1m{:p} {} +{}\033[0m\n", ip, (symbol ? symbol->name : "(k?)"), (symbol ? ip - symbol->address : 0));
} else {
dbgln("\033[31;1m{:p} (?)\033[0m\n", ip);
}
dump_backtrace();
}
{
ProtectedDataMutationScope scope { *this };
m_protected_values.termination_signal = signal;
}
set_should_generate_coredump(!out_of_memory);
address_space().dump_regions();
VERIFY(is_user_process());
die();
// We can not return from here, as there is nowhere
// to unwind to, so die right away.
Thread::current()->die_if_needed();
VERIFY_NOT_REACHED();
}
RefPtr<Process> Process::from_pid(ProcessID pid)
{
return all_instances().with([&](auto const& list) -> RefPtr<Process> {
for (auto const& process : list) {
if (process.pid() == pid)
return &process;
}
return {};
});
}
Process::OpenFileDescriptionAndFlags const* Process::OpenFileDescriptions::get_if_valid(size_t i) const
{
if (m_fds_metadatas.size() <= i)
return nullptr;
if (auto const& metadata = m_fds_metadatas[i]; metadata.is_valid())
return &metadata;
return nullptr;
}
Process::OpenFileDescriptionAndFlags* Process::OpenFileDescriptions::get_if_valid(size_t i)
{
if (m_fds_metadatas.size() <= i)
return nullptr;
if (auto& metadata = m_fds_metadatas[i]; metadata.is_valid())
return &metadata;
return nullptr;
}
Process::OpenFileDescriptionAndFlags const& Process::OpenFileDescriptions::at(size_t i) const
{
VERIFY(m_fds_metadatas[i].is_allocated());
return m_fds_metadatas[i];
}
Process::OpenFileDescriptionAndFlags& Process::OpenFileDescriptions::at(size_t i)
{
VERIFY(m_fds_metadatas[i].is_allocated());
return m_fds_metadatas[i];
}
ErrorOr<NonnullRefPtr<OpenFileDescription>> Process::OpenFileDescriptions::open_file_description(int fd) const
{
if (fd < 0)
return EBADF;
if (static_cast<size_t>(fd) >= m_fds_metadatas.size())
return EBADF;
RefPtr description = m_fds_metadatas[fd].description();
if (!description)
return EBADF;
return description.release_nonnull();
}
void Process::OpenFileDescriptions::enumerate(Function<void(OpenFileDescriptionAndFlags const&)> callback) const
{
for (auto const& file_description_metadata : m_fds_metadatas) {
callback(file_description_metadata);
}
}
ErrorOr<void> Process::OpenFileDescriptions::try_enumerate(Function<ErrorOr<void>(OpenFileDescriptionAndFlags const&)> callback) const
{
for (auto const& file_description_metadata : m_fds_metadatas) {
TRY(callback(file_description_metadata));
}
return {};
}
void Process::OpenFileDescriptions::change_each(Function<void(OpenFileDescriptionAndFlags&)> callback)
{
for (auto& file_description_metadata : m_fds_metadatas) {
callback(file_description_metadata);
}
}
size_t Process::OpenFileDescriptions::open_count() const
{
size_t count = 0;
enumerate([&](auto& file_description_metadata) {
if (file_description_metadata.is_valid())
++count;
});
return count;
}
ErrorOr<Process::ScopedDescriptionAllocation> Process::OpenFileDescriptions::allocate(int first_candidate_fd)
{
for (size_t i = first_candidate_fd; i < max_open(); ++i) {
if (!m_fds_metadatas[i].is_allocated()) {
m_fds_metadatas[i].allocate();
return Process::ScopedDescriptionAllocation { static_cast<int>(i), &m_fds_metadatas[i] };
}
}
return EMFILE;
}
Time kgettimeofday()
{
return TimeManagement::now();
}
siginfo_t Process::wait_info() const
{
siginfo_t siginfo {};
siginfo.si_signo = SIGCHLD;
siginfo.si_pid = pid().value();
siginfo.si_uid = uid().value();
if (m_protected_values.termination_signal != 0) {
siginfo.si_status = m_protected_values.termination_signal;
siginfo.si_code = CLD_KILLED;
} else {
siginfo.si_status = m_protected_values.termination_status;
siginfo.si_code = CLD_EXITED;
}
return siginfo;
}
NonnullRefPtr<Custody> Process::current_directory()
{
return m_current_directory.with([&](auto& current_directory) -> NonnullRefPtr<Custody> {
if (!current_directory)
current_directory = VirtualFileSystem::the().root_custody();
return *current_directory;
});
}
ErrorOr<NonnullOwnPtr<KString>> Process::get_syscall_path_argument(Userspace<char const*> user_path, size_t path_length)
{
if (path_length == 0)
return EINVAL;
if (path_length > PATH_MAX)
return ENAMETOOLONG;
return try_copy_kstring_from_user(user_path, path_length);
}
ErrorOr<NonnullOwnPtr<KString>> Process::get_syscall_path_argument(Syscall::StringArgument const& path)
{
Userspace<char const*> path_characters((FlatPtr)path.characters);
return get_syscall_path_argument(path_characters, path.length);
}
ErrorOr<void> Process::dump_core()
{
VERIFY(is_dumpable());
VERIFY(should_generate_coredump());
dbgln("Generating coredump for pid: {}", pid().value());
auto coredump_path = TRY(KString::formatted("/tmp/coredump/{}_{}_{}", name(), pid().value(), kgettimeofday().to_truncated_seconds()));
auto coredump = TRY(Coredump::try_create(*this, coredump_path->view()));
return coredump->write();
}
ErrorOr<void> Process::dump_perfcore()
{
VERIFY(is_dumpable());
VERIFY(m_perf_event_buffer);
dbgln("Generating perfcore for pid: {}", pid().value());
// Try to generate a filename which isn't already used.
auto base_filename = TRY(KString::formatted("{}_{}", name(), pid().value()));
auto perfcore_filename = TRY(KString::formatted("{}.profile", base_filename));
RefPtr<OpenFileDescription> description;
for (size_t attempt = 1; attempt <= 10; ++attempt) {
auto description_or_error = VirtualFileSystem::the().open(perfcore_filename->view(), O_CREAT | O_EXCL, 0400, current_directory(), UidAndGid { 0, 0 });
if (!description_or_error.is_error()) {
description = description_or_error.release_value();
break;
}
perfcore_filename = TRY(KString::formatted("{}.{}.profile", base_filename, attempt));
}
if (!description) {
dbgln("Failed to generate perfcore for pid {}: Could not generate filename for the perfcore file.", pid().value());
return EEXIST;
}
auto builder = TRY(KBufferBuilder::try_create());
TRY(m_perf_event_buffer->to_json(builder));
auto json = builder.build();
if (!json) {
dbgln("Failed to generate perfcore for pid {}: Could not allocate buffer.", pid().value());
return ENOMEM;
}
auto json_buffer = UserOrKernelBuffer::for_kernel_buffer(json->data());
TRY(description->write(json_buffer, json->size()));
dbgln("Wrote perfcore for pid {} to {}", pid().value(), perfcore_filename);
return {};
}
void Process::finalize()
{
VERIFY(Thread::current() == g_finalizer);
dbgln_if(PROCESS_DEBUG, "Finalizing process {}", *this);
if (veil_state() == VeilState::Dropped)
dbgln("\x1b[01;31mProcess '{}' exited with the veil left open\x1b[0m", name());
if (g_init_pid != 0 && pid() == g_init_pid)
PANIC("Init process quit unexpectedly. Exit code: {}", m_protected_values.termination_status);
if (is_dumpable()) {
if (m_should_generate_coredump) {
auto result = dump_core();
if (result.is_error()) {
critical_dmesgln("Failed to write coredump: {}", result.error());
}
}
if (m_perf_event_buffer) {
auto result = dump_perfcore();
if (result.is_error())
critical_dmesgln("Failed to write perfcore: {}", result.error());
TimeManagement::the().disable_profile_timer();
}
}
m_threads_for_coredump.clear();
if (m_alarm_timer)
TimerQueue::the().cancel_timer(m_alarm_timer.release_nonnull());
m_fds.with_exclusive([](auto& fds) { fds.clear(); });
m_tty = nullptr;
m_executable = nullptr;
m_arguments.clear();
m_environment.clear();
m_state.store(State::Dead, AK::MemoryOrder::memory_order_release);
{
if (auto parent_process = Process::from_pid(ppid())) {
if (parent_process->is_user_process() && (parent_process->m_signal_action_data[SIGCHLD].flags & SA_NOCLDWAIT) != SA_NOCLDWAIT)
(void)parent_process->send_signal(SIGCHLD, this);
}
}
if (!!ppid()) {
if (auto parent = Process::from_pid(ppid())) {
parent->m_ticks_in_user_for_dead_children += m_ticks_in_user + m_ticks_in_user_for_dead_children;
parent->m_ticks_in_kernel_for_dead_children += m_ticks_in_kernel + m_ticks_in_kernel_for_dead_children;
}
}
unblock_waiters(Thread::WaitBlocker::UnblockFlags::Terminated);
m_space->remove_all_regions({});
VERIFY(ref_count() > 0);
// WaitBlockerSet::finalize will be in charge of dropping the last
// reference if there are still waiters around, or whenever the last
// waitable states are consumed. Unless there is no parent around
// anymore, in which case we'll just drop it right away.
m_wait_blocker_set.finalize();
}
void Process::disowned_by_waiter(Process& process)
{
m_wait_blocker_set.disowned_by_waiter(process);
}
void Process::unblock_waiters(Thread::WaitBlocker::UnblockFlags flags, u8 signal)
{
RefPtr<Process> waiter_process;
if (auto* my_tracer = tracer())
waiter_process = Process::from_pid(my_tracer->tracer_pid());
else
waiter_process = Process::from_pid(ppid());
if (waiter_process)
waiter_process->m_wait_blocker_set.unblock(*this, flags, signal);
}
void Process::die()
{
auto expected = State::Running;
if (!m_state.compare_exchange_strong(expected, State::Dying, AK::memory_order_acquire)) {
// It's possible that another thread calls this at almost the same time
// as we can't always instantly kill other threads (they may be blocked)
// So if we already were called then other threads should stop running
// momentarily and we only really need to service the first thread
return;
}
// Let go of the TTY, otherwise a slave PTY may keep the master PTY from
// getting an EOF when the last process using the slave PTY dies.
// If the master PTY owner relies on an EOF to know when to wait() on a
// slave owner, we have to allow the PTY pair to be torn down.
m_tty = nullptr;
VERIFY(m_threads_for_coredump.is_empty());
for_each_thread([&](auto& thread) {
auto result = m_threads_for_coredump.try_append(thread);
if (result.is_error())
dbgln("Failed to add thread {} to coredump due to OOM", thread.tid());
});
all_instances().with([&](auto const& list) {
for (auto it = list.begin(); it != list.end();) {
auto& process = *it;
++it;
if (process.has_tracee_thread(pid())) {
dbgln_if(PROCESS_DEBUG, "Process {} ({}) is attached by {} ({}) which will exit", process.name(), process.pid(), name(), pid());
process.stop_tracing();
auto err = process.send_signal(SIGSTOP, this);
if (err.is_error())
dbgln("Failed to send the SIGSTOP signal to {} ({})", process.name(), process.pid());
}
}
});
kill_all_threads();
#ifdef ENABLE_KERNEL_COVERAGE_COLLECTION
KCOVDevice::free_process();
#endif
}
void Process::terminate_due_to_signal(u8 signal)
{
VERIFY_INTERRUPTS_DISABLED();
VERIFY(signal < 32);
VERIFY(&Process::current() == this);
dbgln("Terminating {} due to signal {}", *this, signal);
{
ProtectedDataMutationScope scope { *this };
m_protected_values.termination_status = 0;
m_protected_values.termination_signal = signal;
}
die();
}
ErrorOr<void> Process::send_signal(u8 signal, Process* sender)
{
VERIFY(is_user_process());
// Try to send it to the "obvious" main thread:
auto receiver_thread = Thread::from_tid(pid().value());
// If the main thread has died, there may still be other threads:
if (!receiver_thread) {
// The first one should be good enough.
// Neither kill(2) nor kill(3) specify any selection procedure.
for_each_thread([&receiver_thread](Thread& thread) -> IterationDecision {
receiver_thread = &thread;
return IterationDecision::Break;
});
}
if (receiver_thread) {
receiver_thread->send_signal(signal, sender);
return {};
}
return ESRCH;
}
RefPtr<Thread> Process::create_kernel_thread(void (*entry)(void*), void* entry_data, u32 priority, NonnullOwnPtr<KString> name, u32 affinity, bool joinable)
{
VERIFY((priority >= THREAD_PRIORITY_MIN) && (priority <= THREAD_PRIORITY_MAX));
// FIXME: Do something with guard pages?
auto thread_or_error = Thread::try_create(*this);
if (thread_or_error.is_error())
return {};
auto thread = thread_or_error.release_value();
thread->set_name(move(name));
thread->set_affinity(affinity);
thread->set_priority(priority);
if (!joinable)
thread->detach();
auto& regs = thread->regs();
regs.set_ip((FlatPtr)entry);
regs.set_sp((FlatPtr)entry_data); // entry function argument is expected to be in the SP register
SpinlockLocker lock(g_scheduler_lock);
thread->set_state(Thread::State::Runnable);
return thread;
}
void Process::OpenFileDescriptionAndFlags::clear()
{
// FIXME: Verify Process::m_fds_lock is locked!
m_description = nullptr;
m_flags = 0;
}
void Process::OpenFileDescriptionAndFlags::set(NonnullRefPtr<OpenFileDescription>&& description, u32 flags)
{
// FIXME: Verify Process::m_fds_lock is locked!
m_description = move(description);
m_flags = flags;
}
void Process::set_tty(TTY* tty)
{
m_tty = tty;
}
ErrorOr<void> Process::start_tracing_from(ProcessID tracer)
{
m_tracer = TRY(ThreadTracer::try_create(tracer));
return {};
}
void Process::stop_tracing()
{
m_tracer = nullptr;
}
void Process::tracer_trap(Thread& thread, RegisterState const& regs)
{
VERIFY(m_tracer.ptr());
m_tracer->set_regs(regs);
thread.send_urgent_signal_to_self(SIGTRAP);
}
bool Process::create_perf_events_buffer_if_needed()
{
if (m_perf_event_buffer)
return true;
m_perf_event_buffer = PerformanceEventBuffer::try_create_with_size(4 * MiB);
if (!m_perf_event_buffer)
return false;
return !m_perf_event_buffer->add_process(*this, ProcessEventType::Create).is_error();
}
void Process::delete_perf_events_buffer()
{
if (m_perf_event_buffer)
m_perf_event_buffer = nullptr;
}
bool Process::remove_thread(Thread& thread)
{
ProtectedDataMutationScope scope { *this };
auto thread_cnt_before = m_protected_values.thread_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
VERIFY(thread_cnt_before != 0);
thread_list().with([&](auto& thread_list) {
thread_list.remove(thread);
});
return thread_cnt_before == 1;
}
bool Process::add_thread(Thread& thread)
{
ProtectedDataMutationScope scope { *this };
bool is_first = m_protected_values.thread_count.fetch_add(1, AK::MemoryOrder::memory_order_relaxed) == 0;
thread_list().with([&](auto& thread_list) {
thread_list.append(thread);
});
return is_first;
}
void Process::set_dumpable(bool dumpable)
{
if (dumpable == m_protected_values.dumpable)
return;
ProtectedDataMutationScope scope { *this };
m_protected_values.dumpable = dumpable;
}
ErrorOr<void> Process::set_coredump_property(NonnullOwnPtr<KString> key, NonnullOwnPtr<KString> value)
{
return m_coredump_properties.with([&](auto& coredump_properties) -> ErrorOr<void> {
// Write it into the first available property slot.
for (auto& slot : coredump_properties) {
if (slot.key)
continue;
slot.key = move(key);
slot.value = move(value);
return {};
}
return ENOBUFS;
});
}
ErrorOr<void> Process::try_set_coredump_property(StringView key, StringView value)
{
auto key_kstring = TRY(KString::try_create(key));
auto value_kstring = TRY(KString::try_create(value));
return set_coredump_property(move(key_kstring), move(value_kstring));
};
static constexpr StringView to_string(Pledge promise)
{
#define __ENUMERATE_PLEDGE_PROMISE(x) \
case Pledge::x: \
return #x;
switch (promise) {
ENUMERATE_PLEDGE_PROMISES
}
#undef __ENUMERATE_PLEDGE_PROMISE
VERIFY_NOT_REACHED();
}
ErrorOr<void> Process::require_no_promises() const
{
if (!has_promises())
return {};
dbgln("Has made a promise");
Thread::current()->set_promise_violation_pending(true);
return EPROMISEVIOLATION;
}
ErrorOr<void> Process::require_promise(Pledge promise)
{
if (!has_promises())
return {};
if (has_promised(promise))
return {};
dbgln("Has not pledged {}", to_string(promise));
Thread::current()->set_promise_violation_pending(true);
(void)try_set_coredump_property("pledge_violation"sv, to_string(promise));
return EPROMISEVIOLATION;
}
}