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ladybird/Kernel/Process.cpp
Liav A 5e062414c1 Kernel: Add support for jails 
Our implementation for Jails resembles much of how FreeBSD jails are
working - it's essentially only a matter of using a RefPtr in the
Process class to a Jail object. Then, when we iterate over all processes
in various cases, we could ensure if either the current process is in
jail and therefore should be restricted what is visible in terms of
PID isolation, and also to be able to expose metadata about Jails in
/sys/kernel/jails node (which does not reveal anything to a process
which is in jail).

A lifetime model for the Jail object is currently plain simple - there's
simpy no way to manually delete a Jail object once it was created. Such
feature should be carefully designed to allow safe destruction of a Jail
without the possibility of releasing a process which is in Jail from the
actual jail. Each process which is attached into a Jail cannot leave it
until the end of a Process (i.e. when finalizing a Process). All jails
are kept being referenced in the JailManagement. When a last attached
process is finalized, the Jail is automatically destroyed.
2022-11-05 18:00:58 -06:00

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/*
* Copyright (c) 2018-2022, 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/Coredump.h>
#include <Kernel/Credentials.h>
#include <Kernel/Debug.h>
#include <Kernel/Devices/DeviceManagement.h>
#include <Kernel/InterruptDisabler.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 { LockRank::None };
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;
}
ErrorOr<void> Process::for_each_in_same_jail(Function<ErrorOr<void>(Process&)> callback)
{
ErrorOr<void> result {};
Process::all_instances().with([&](auto const& list) {
Process::current().jail().with([&](auto my_jail) {
for (auto& process : list) {
if (!my_jail) {
result = callback(process);
} else {
// Note: Don't acquire the process jail spinlock twice if it's the same process
// we are currently inspecting.
if (&Process::current() == &process) {
result = callback(process);
} else {
process.jail().with([&](auto& their_jail) {
if (their_jail.ptr() == my_jail.ptr())
result = callback(process);
});
}
}
if (result.is_error())
break;
}
});
});
return result;
}
ErrorOr<void> Process::for_each_child_in_same_jail(Function<ErrorOr<void>(Process&)> callback)
{
ProcessID my_pid = pid();
ErrorOr<void> result {};
Process::all_instances().with([&](auto const& list) {
jail().with([&](auto my_jail) {
for (auto& process : list) {
if (!my_jail) {
if (process.ppid() == my_pid || process.has_tracee_thread(pid()))
result = callback(process);
} else {
// FIXME: Is it possible to have a child process being pointing to itself
// as the parent process under normal conditions?
// Note: Don't acquire the process jail spinlock twice if it's the same process
// we are currently inspecting.
if (&Process::current() == &process && (process.ppid() == my_pid || process.has_tracee_thread(pid()))) {
result = callback(process);
} else {
process.jail().with([&](auto& their_jail) {
if ((their_jail.ptr() == my_jail.ptr()) && (process.ppid() == my_pid || process.has_tracee_thread(pid())))
result = callback(process);
});
}
}
if (result.is_error())
break;
}
});
});
return result;
}
ErrorOr<void> Process::for_each_in_pgrp_in_same_jail(ProcessGroupID pgid, Function<ErrorOr<void>(Process&)> callback)
{
ErrorOr<void> result {};
Process::all_instances().with([&](auto const& list) {
jail().with([&](auto my_jail) {
for (auto& process : list) {
if (!my_jail) {
if (!process.is_dead() && process.pgid() == pgid)
result = callback(process);
} else {
// Note: Don't acquire the process jail spinlock twice if it's the same process
// we are currently inspecting.
if (&Process::current() == &process && !process.is_dead() && process.pgid() == pgid) {
result = callback(process);
} else {
process.jail().with([&](auto& their_jail) {
if ((their_jail.ptr() == my_jail.ptr()) && !process.is_dead() && process.pgid() == pgid)
result = callback(process);
});
}
}
if (result.is_error())
break;
}
});
});
return result;
}
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();
}
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()
LockRefPtr<Process> new_process = process;
all_instances().with([&](auto& list) {
list.prepend(process);
});
}
ErrorOr<NonnullLockRefPtr<Process>> Process::try_create_user_process(LockRefPtr<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;
}
LockRefPtr<Process> Process::create_kernel_process(LockRefPtr<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
#elif ARCH(X86_64)
first_thread->regs().rdi = FlatPtr(entry_data); // entry function argument is expected to be in regs.rdi
#elif ARCH(AARCH64)
(void)entry_data;
TODO_AARCH64();
#else
# error Unknown architecture
#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_do_not_access_directly }, false);
});
}
void Process::unprotect_data()
{
m_protected_data_refs.ref([&]() {
MM.set_page_writable_direct(VirtualAddress { &this->m_protected_values_do_not_access_directly }, true);
});
}
ErrorOr<NonnullLockRefPtr<Process>> Process::try_create(LockRefPtr<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)
{
OwnPtr<Memory::AddressSpace> new_address_space;
if (fork_parent) {
TRY(fork_parent->address_space().with([&](auto& parent_address_space) -> ErrorOr<void> {
new_address_space = TRY(Memory::AddressSpace::try_create(parent_address_space.ptr()));
return {};
}));
} else {
new_address_space = TRY(Memory::AddressSpace::try_create(nullptr));
}
auto unveil_tree = UnveilNode { TRY(KString::try_create("/"sv)), UnveilMetadata(TRY(KString::try_create("/"sv))) };
auto credentials = TRY(Credentials::create(uid, gid, uid, gid, uid, gid, {}));
auto process = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) Process(move(name), move(credentials), ppid, is_kernel_process, move(current_directory), move(executable), tty, move(unveil_tree))));
TRY(process->attach_resources(new_address_space.release_nonnull(), first_thread, fork_parent));
return process;
}
Process::Process(NonnullOwnPtr<KString> name, NonnullRefPtr<Credentials> credentials, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, TTY* tty, UnveilNode unveil_tree)
: m_name(move(name))
, m_space(LockRank::None)
, m_protected_data_lock(LockRank::None)
, m_is_kernel_process(is_kernel_process)
, m_executable(LockRank::None, move(executable))
, m_current_directory(LockRank::None, move(current_directory))
, m_tty(tty)
, m_unveil_data(LockRank::None, move(unveil_tree))
, m_wait_blocker_set(*this)
{
// Ensure that we protect the process data when exiting the constructor.
with_mutable_protected_data([&](auto& protected_data) {
protected_data.pid = allocate_pid();
protected_data.ppid = ppid;
protected_data.credentials = move(credentials);
});
dbgln_if(PROCESS_DEBUG, "Created new process {}({})", m_name, this->pid().value());
}
ErrorOr<void> Process::attach_resources(NonnullOwnPtr<Memory::AddressSpace>&& preallocated_space, LockRefPtr<Thread>& first_thread, Process* fork_parent)
{
m_space.with([&](auto& space) {
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)));
// This is not actually explicitly verified by any official documentation,
// but it's not listed anywhere as being cleared, and rsync expects it to work like this.
if (fork_parent)
m_signal_action_data = fork_parent->m_signal_action_data;
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"sv, 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();
}
with_mutable_protected_data([&](auto& protected_data) {
protected_data.termination_signal = signal;
});
set_should_generate_coredump(!out_of_memory);
if constexpr (DUMP_REGIONS_ON_CRASH) {
address_space().with([](auto& space) { 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();
}
LockRefPtr<Process> Process::from_pid_in_same_jail(ProcessID pid)
{
return Process::current().jail().with([&](auto& my_jail) -> LockRefPtr<Process> {
return all_instances().with([&](auto const& list) -> LockRefPtr<Process> {
if (!my_jail) {
for (auto& process : list) {
if (process.pid() == pid) {
return process;
}
}
} else {
for (auto& process : list) {
if (process.pid() == pid) {
return process.jail().with([&](auto& other_process_jail) -> LockRefPtr<Process> {
if (other_process_jail.ptr() == my_jail.ptr())
return process;
return {};
});
}
}
}
return {};
});
});
}
LockRefPtr<Process> Process::from_pid_ignoring_jails(ProcessID pid)
{
return all_instances().with([&](auto const& list) -> LockRefPtr<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<NonnullLockRefPtr<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;
LockRefPtr 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
{
auto credentials = this->credentials();
siginfo_t siginfo {};
siginfo.si_signo = SIGCHLD;
siginfo.si_pid = pid().value();
siginfo.si_uid = credentials->uid().value();
with_protected_data([&](auto& protected_data) {
if (protected_data.termination_signal != 0) {
siginfo.si_status = protected_data.termination_signal;
siginfo.si_code = CLD_KILLED;
} else {
siginfo.si_status = protected_data.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));
LockRefPtr<OpenFileDescription> description;
auto credentials = this->credentials();
for (size_t attempt = 1; attempt <= 10; ++attempt) {
auto description_or_error = VirtualFileSystem::the().open(credentials, 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: {}", termination_status());
if (is_dumpable()) {
if (m_should_generate_coredump) {
auto result = dump_core();
if (result.is_error()) {
dmesgln("Failed to write coredump for pid {}: {}", pid(), result.error());
}
}
if (m_perf_event_buffer) {
auto result = dump_perfcore();
if (result.is_error())
dmesgln("Failed to write perfcore for pid {}: {}", pid(), 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.with([](auto& executable) { executable = nullptr; });
m_attached_jail.with([](auto& jail) {
if (jail)
jail->detach({});
jail = nullptr;
});
m_arguments.clear();
m_environment.clear();
m_state.store(State::Dead, AK::MemoryOrder::memory_order_release);
{
if (auto parent_process = Process::from_pid_ignoring_jails(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_ignoring_jails(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.with([](auto& space) { 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)
{
LockRefPtr<Process> waiter_process;
if (auto* my_tracer = tracer())
waiter_process = Process::from_pid_ignoring_jails(my_tracer->tracer_pid());
else
waiter_process = Process::from_pid_ignoring_jails(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 < NSIG);
VERIFY(&Process::current() == this);
dbgln("Terminating {} due to signal {}", *this, signal);
with_mutable_protected_data([&](auto& protected_data) {
protected_data.termination_status = 0;
protected_data.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;
}
LockRefPtr<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(NonnullLockRefPtr<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)
{
u32 thread_count_before = 0;
thread_list().with([&](auto& thread_list) {
thread_list.remove(thread);
with_mutable_protected_data([&](auto& protected_data) {
thread_count_before = protected_data.thread_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
VERIFY(thread_count_before != 0);
});
});
return thread_count_before == 1;
}
bool Process::add_thread(Thread& thread)
{
bool is_first = false;
thread_list().with([&](auto& thread_list) {
thread_list.append(thread);
with_mutable_protected_data([&](auto& protected_data) {
is_first = protected_data.thread_count.fetch_add(1, AK::MemoryOrder::memory_order_relaxed) == 0;
});
});
return is_first;
}
void Process::set_dumpable(bool dumpable)
{
with_mutable_protected_data([&](auto& protected_data) {
protected_data.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##sv;
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;
}
NonnullRefPtr<Credentials> Process::credentials() const
{
return with_protected_data([&](auto& protected_data) -> NonnullRefPtr<Credentials> {
return *protected_data.credentials;
});
}
RefPtr<Custody> Process::executable()
{
return m_executable.with([](auto& executable) { return executable; });
}
RefPtr<Custody const> Process::executable() const
{
return m_executable.with([](auto& executable) { return executable; });
}
}
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