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Kernel: Don't allocate memory for names of processes and threads

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Instead, use the FixedCharBuffer class to ensure we always use a static
buffer storage for these names. This ensures that if a Process or a
Thread were created, there's a guarantee that setting a new name will
never fail, as only copying of strings should be done to that static
storage.

The limits which are set are 32 characters for processes' names and 64
characters for thread names - this is because threads' names could be
more verbose than processes' names.
This commit is contained in:
Liav A 2023-07-17 18:34:19 +03:00 • committed by Andrew Kaster
parent 0d30f558f4
commit 3fd4997fc2
22 changed files with 102 additions and 110 deletions
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50
Kernel/Tasks/Process.cpp
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@ -219,8 +219,7 @@ ErrorOr<Process::ProcessAndFirstThread> Process::create_user_process(StringView
}
auto path_string = TRY(KString::try_create(path));
auto name = TRY(KString::try_create(parts.last()));
auto [process, first_thread] = TRY(Process::create(move(name), uid, gid, ProcessID(0), false, VirtualFileSystem::the().root_custody(), nullptr, tty));
auto [process, first_thread] = TRY(Process::create(parts.last(), 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()));
@ -255,9 +254,9 @@ ErrorOr<Process::ProcessAndFirstThread> Process::create_user_process(StringView
return ProcessAndFirstThread { move(process), move(first_thread) };
}
ErrorOr<Process::ProcessAndFirstThread> Process::create_kernel_process(NonnullOwnPtr<KString> name, void (*entry)(void*), void* entry_data, u32 affinity, RegisterProcess do_register)
ErrorOr<Process::ProcessAndFirstThread> Process::create_kernel_process(StringView name, void (*entry)(void*), void* entry_data, u32 affinity, RegisterProcess do_register)
{
auto process_and_first_thread = TRY(Process::create(move(name), UserID(0), GroupID(0), ProcessID(0), true));
auto process_and_first_thread = TRY(Process::create(name, UserID(0), GroupID(0), ProcessID(0), true));
auto& process = *process_and_first_thread.process;
auto& thread = *process_and_first_thread.first_thread;
@ -286,13 +285,22 @@ void Process::unprotect_data()
});
}
ErrorOr<Process::ProcessAndFirstThread> Process::create(NonnullOwnPtr<KString> name, UserID uid, GroupID gid, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, RefPtr<TTY> tty, Process* fork_parent)
ErrorOr<Process::ProcessAndFirstThread> Process::create_with_forked_name(UserID uid, GroupID gid, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, RefPtr<TTY> tty, Process* fork_parent)
{
Process::Name name {};
Process::current().name().with([&name](auto& process_name) {
name.store_characters(process_name.representable_view());
});
return TRY(Process::create(name.representable_view(), uid, gid, ppid, is_kernel_process, current_directory, executable, tty, fork_parent));
}
ErrorOr<Process::ProcessAndFirstThread> Process::create(StringView name, UserID uid, GroupID gid, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, RefPtr<TTY> tty, Process* fork_parent)
{
auto unveil_tree = UnveilNode { TRY(KString::try_create("/"sv)), UnveilMetadata(TRY(KString::try_create("/"sv))) };
auto exec_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, {}, fork_parent ? fork_parent->sid() : 0, fork_parent ? fork_parent->pgid() : 0));
auto process = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Process(move(name), move(credentials), ppid, is_kernel_process, move(current_directory), move(executable), tty, move(unveil_tree), move(exec_unveil_tree), kgettimeofday())));
auto process = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Process(name, move(credentials), ppid, is_kernel_process, move(current_directory), move(executable), tty, move(unveil_tree), move(exec_unveil_tree), kgettimeofday())));
OwnPtr<Memory::AddressSpace> new_address_space;
if (fork_parent) {
@ -309,9 +317,8 @@ ErrorOr<Process::ProcessAndFirstThread> Process::create(NonnullOwnPtr<KString> n
return ProcessAndFirstThread { move(process), move(first_thread) };
}
Process::Process(NonnullOwnPtr<KString> name, NonnullRefPtr<Credentials> credentials, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, RefPtr<TTY> tty, UnveilNode unveil_tree, UnveilNode exec_unveil_tree, UnixDateTime creation_time)
: m_name(move(name))
, m_is_kernel_process(is_kernel_process)
Process::Process(StringView name, NonnullRefPtr<Credentials> credentials, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, RefPtr<TTY> tty, UnveilNode unveil_tree, UnveilNode exec_unveil_tree, UnixDateTime creation_time)
: m_is_kernel_process(is_kernel_process)
, m_executable(move(executable))
, m_current_directory(move(current_directory))
, m_creation_time(creation_time)
@ -319,6 +326,7 @@ Process::Process(NonnullOwnPtr<KString> name, NonnullRefPtr<Credentials> credent
, m_exec_unveil_data(move(exec_unveil_tree))
, m_wait_blocker_set(*this)
{
set_name(name);
// Ensure that we protect the process data when exiting the constructor.
with_mutable_protected_data([&](auto& protected_data) {
protected_data.pid = allocate_pid();
@ -329,7 +337,7 @@ Process::Process(NonnullOwnPtr<KString> name, NonnullRefPtr<Credentials> credent
if constexpr (PROCESS_DEBUG) {
this->name().with([&](auto& process_name) {
dbgln("Created new process {}({})", process_name->view(), this->pid().value());
dbgln("Created new process {}({})", process_name.representable_view(), this->pid().value());
});
}
}
@ -701,7 +709,7 @@ ErrorOr<void> Process::dump_core()
return {};
}
auto coredump_path = TRY(name().with([&](auto& process_name) {
return KString::formatted("{}/{}_{}_{}", coredump_directory_path->view(), process_name->view(), pid().value(), kgettimeofday().seconds_since_epoch());
return KString::formatted("{}/{}_{}_{}", coredump_directory_path->view(), process_name.representable_view(), pid().value(), kgettimeofday().seconds_since_epoch());
}));
auto coredump = TRY(Coredump::try_create(*this, coredump_path->view()));
return coredump->write();
@ -715,7 +723,7 @@ ErrorOr<void> Process::dump_perfcore()
// Try to generate a filename which isn't already used.
auto base_filename = TRY(name().with([&](auto& process_name) {
return KString::formatted("{}_{}", process_name->view(), pid().value());
return KString::formatted("{}_{}", process_name.representable_view(), pid().value());
}));
auto perfcore_filename = TRY(KString::formatted("{}.profile", base_filename));
RefPtr<OpenFileDescription> description;
@ -757,7 +765,7 @@ void Process::finalize()
if (veil_state() == VeilState::Dropped) {
name().with([&](auto& process_name) {
dbgln("\x1b[01;31mProcess '{}' exited with the veil left open\x1b[0m", process_name->view());
dbgln("\x1b[01;31mProcess '{}' exited with the veil left open\x1b[0m", process_name.representable_view());
});
}
@ -888,7 +896,7 @@ void Process::die()
if constexpr (PROCESS_DEBUG) {
process.name().with([&](auto& process_name) {
name().with([&](auto& name) {
dbgln("Process {} ({}) is attached by {} ({}) which will exit", process_name->view(), process.pid(), name->view(), pid());
dbgln("Process {} ({}) is attached by {} ({}) which will exit", process_name.representable_view(), process.pid(), name.representable_view(), pid());
});
});
}
@ -896,7 +904,7 @@ void Process::die()
auto err = process.send_signal(SIGSTOP, this);
if (err.is_error()) {
process.name().with([&](auto& process_name) {
dbgln("Failed to send the SIGSTOP signal to {} ({})", process_name->view(), process.pid());
dbgln("Failed to send the SIGSTOP signal to {} ({})", process_name.representable_view(), process.pid());
});
}
}
@ -943,14 +951,14 @@ ErrorOr<void> Process::send_signal(u8 signal, Process* sender)
return ESRCH;
}
ErrorOr<NonnullRefPtr<Thread>> Process::create_kernel_thread(void (*entry)(void*), void* entry_data, u32 priority, NonnullOwnPtr<KString> name, u32 affinity, bool joinable)
ErrorOr<NonnullRefPtr<Thread>> Process::create_kernel_thread(void (*entry)(void*), void* entry_data, u32 priority, StringView name, u32 affinity, bool joinable)
{
VERIFY((priority >= THREAD_PRIORITY_MIN) && (priority <= THREAD_PRIORITY_MAX));
// FIXME: Do something with guard pages?
auto thread = TRY(Thread::create(*this));
thread->set_name(move(name));
thread->set_name(name);
thread->set_affinity(affinity);
thread->set_priority(priority);
if (!joinable)
@ -1138,15 +1146,15 @@ ErrorOr<NonnullRefPtr<Custody>> Process::custody_for_dirfd(int dirfd)
return *description->custody();
}
SpinlockProtected<NonnullOwnPtr<KString>, LockRank::None> const& Process::name() const
SpinlockProtected<Process::Name, LockRank::None> const& Process::name() const
{
return m_name;
}
void Process::set_name(NonnullOwnPtr<KString> name)
void Process::set_name(StringView name)
{
m_name.with([&](auto& this_name) {
this_name = move(name);
m_name.with([name](auto& process_name) {
process_name.store_characters(name);
});
}