mirror of
https://github.com/RGBCube/serenity
synced 2025-05-29 20:35:13 +00:00
Rework process states to make a bit more sense.
Processes are either alive (with many substates), dead or forgiven. A dead process is forgiven when the parent waitpid()s on it. Dead orphans are also forgiven. There's a lot of work to be done around this.
This commit is contained in:
Andreas Kling
parent
71bffa9864
commit
678882e020
4 changed files with 154 additions and 93 deletions
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@ -705,15 +705,6 @@ void Process::dumpRegions()
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}
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}
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void Process::notify_waiters(pid_t waitee, int exit_status, int signal)
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{
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ASSERT_INTERRUPTS_DISABLED();
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for (auto* process = s_processes->head(); process; process = process->next()) {
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if (process->waitee() == waitee)
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process->m_waiteeStatus = (exit_status << 8) | (signal);
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}
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}
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void Process::sys$exit(int status)
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{
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cli();
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@ -721,59 +712,76 @@ void Process::sys$exit(int status)
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kprintf("sys$exit: %s(%u) exit with status %d\n", name().characters(), pid(), status);
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#endif
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set_state(Exiting);
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s_processes->remove(this);
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notify_waiters(m_pid, status, 0);
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set_state(Dead);
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m_termination_status = status;
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m_termination_signal = 0;
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if (!scheduleNewProcess()) {
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kprintf("Process::sys$exit: Failed to schedule a new process :(\n");
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HANG;
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}
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s_deadProcesses->append(this);
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switchNow();
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}
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void Process::terminate_due_to_signal(int signal, Process* sender)
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void Process::terminate_due_to_signal(byte signal)
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{
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ASSERT_INTERRUPTS_DISABLED();
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bool wasCurrent = this == current;
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set_state(Exiting);
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s_processes->remove(this);
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notify_waiters(m_pid, 0, signal);
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if (wasCurrent) {
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kprintf("Current process (%u) committing suicide!\n", pid());
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if (!scheduleNewProcess()) {
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kprintf("Process::send_signal: Failed to schedule a new process :(\n");
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HANG;
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}
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}
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s_deadProcesses->append(this);
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if (wasCurrent)
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switchNow();
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ASSERT(signal < 32);
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dbgprintf("terminate_due_to_signal %s(%u) <- %u\n", name().characters(), pid(), signal);
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m_termination_status = 0;
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m_termination_signal = signal;
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set_state(Dead);
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}
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void Process::send_signal(int signal, Process* sender)
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void Process::send_signal(byte signal, Process* sender)
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{
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ASSERT_INTERRUPTS_DISABLED();
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ASSERT(signal < 32);
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// FIXME: Handle send_signal to self.
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ASSERT(this != sender);
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m_pending_signals |= 1 << signal;
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if (sender)
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dbgprintf("signal: %s(%u) sent %d to %s(%u)\n", sender->name().characters(), sender->pid(), signal, name().characters(), pid());
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else
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dbgprintf("signal: kernel sent %d to %s(%u)\n", signal, name().characters(), pid());
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}
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bool Process::has_unmasked_pending_signals() const
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{
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return m_pending_signals & ~m_signal_mask;
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}
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void Process::dispatch_one_pending_signal()
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{
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ASSERT_INTERRUPTS_DISABLED();
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dword signal_candidates = m_pending_signals & ~m_signal_mask;
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ASSERT(signal_candidates);
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byte signal = 0;
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for (; signal < 32; ++signal) {
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if (signal_candidates & (1 << signal)) {
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break;
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}
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}
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dispatch_signal(signal);
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}
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void Process::dispatch_signal(byte signal)
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{
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ASSERT_INTERRUPTS_DISABLED();
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ASSERT(signal < 32);
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dbgprintf("dispatch_signal %s(%u) <- %u\n", name().characters(), pid(), signal);
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auto& action = m_signal_action_data[signal];
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// FIXME: Implement SA_SIGINFO signal handlers.
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ASSERT(!(action.flags & SA_SIGINFO));
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auto handler_laddr = action.handler_or_sigaction;
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if (handler_laddr.is_null())
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return terminate_due_to_signal(signal, sender);
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if (handler_laddr.is_null()) {
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// FIXME: Is termination really always the appropriate action?
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return terminate_due_to_signal(signal);
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}
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word ret_cs = m_tss.cs;
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dword ret_eip = m_tss.eip;
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@ -781,6 +789,7 @@ void Process::send_signal(int signal, Process* sender)
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if ((ret_cs & 3) == 0) {
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// FIXME: Handle send_signal to process currently in kernel code.
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kprintf("Boo! dispatch_signal with return to %w:%x\n", ret_cs, ret_eip);
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ASSERT_NOT_REACHED();
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}
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@ -801,7 +810,9 @@ void Process::send_signal(int signal, Process* sender)
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m_tss.eip = handler_laddr.get();
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if (m_return_from_signal_trampoline.is_null()) {
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auto* region = allocate_region(LinearAddress(), PAGE_SIZE, "signal_trampoline", true, true); // FIXME: Remap as read-only after setup.
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// FIXME: This should be a global trampoline shared by all processes, not one created per process!
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// FIXME: Remap as read-only after setup.
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auto* region = allocate_region(LinearAddress(), PAGE_SIZE, "signal_trampoline", true, true);
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m_return_from_signal_trampoline = region->linearAddress;
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byte* code_ptr = m_return_from_signal_trampoline.asPtr();
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*code_ptr++ = 0x61; // popa
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@ -809,16 +820,14 @@ void Process::send_signal(int signal, Process* sender)
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*code_ptr++ = 0xc3; // ret
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*code_ptr++ = 0x0f; // ud2
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*code_ptr++ = 0x0b;
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// FIXME: For !SA_NODEFER, maybe we could do something like emitting an int 0x80 syscall here that
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// unmasks the signal so it can be received again? I guess then I would need one trampoline
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// per signal number if it's hard-coded, but it's just a few bytes per each.
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}
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push_value_on_stack(m_return_from_signal_trampoline.get());
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dbgprintf("signal: %s(%u) sent %d to %s(%u)\n", sender->name().characters(), sender->pid(), signal, name().characters(), pid());
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if (current == this) {
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sched_yield();
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ASSERT_NOT_REACHED();
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}
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dbgprintf("signal: Okay, %s(%u) has been primed\n", name().characters(), pid());
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}
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void Process::push_value_on_stack(dword value)
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@ -828,29 +837,19 @@ void Process::push_value_on_stack(dword value)
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*stack_ptr = value;
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}
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void Process::processDidCrash(Process* crashedProcess)
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void Process::crash()
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{
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ASSERT_INTERRUPTS_DISABLED();
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ASSERT(state() != Dead);
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if (crashedProcess->state() == Crashing) {
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kprintf("Double crash :(\n");
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HANG;
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}
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crashedProcess->set_state(Crashing);
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crashedProcess->dumpRegions();
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s_processes->remove(crashedProcess);
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notify_waiters(crashedProcess->m_pid, 0, SIGSEGV);
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m_termination_signal = SIGSEGV;
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set_state(Dead);
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dumpRegions();
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if (!scheduleNewProcess()) {
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kprintf("Process::processDidCrash: Failed to schedule a new process :(\n");
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kprintf("Process::crash: Failed to schedule a new process :(\n");
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HANG;
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}
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s_deadProcesses->append(crashedProcess);
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switchNow();
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}
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@ -896,6 +895,30 @@ void switchNow()
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);
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}
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template<typename Callback>
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static void for_each_process_in_state(Process::State state, Callback callback)
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{
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ASSERT_INTERRUPTS_DISABLED();
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for (auto* process = s_processes->head(); process;) {
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auto* next_process = process->next();
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if (process->state() == state)
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callback(*process);
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process = next_process;
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}
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}
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template<typename Callback>
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static void for_each_process_not_in_state(Process::State state, Callback callback)
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{
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ASSERT_INTERRUPTS_DISABLED();
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for (auto* process = s_processes->head(); process;) {
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auto* next_process = process->next();
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if (process->state() != state)
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callback(*process);
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process = next_process;
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}
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}
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bool scheduleNewProcess()
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{
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ASSERT_INTERRUPTS_DISABLED();
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@ -909,28 +932,55 @@ bool scheduleNewProcess()
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// Check and unblock processes whose wait conditions have been met.
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for (auto* process = s_processes->head(); process; process = process->next()) {
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if (process->state() == Process::BlockedSleep) {
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if (process->wakeupTime() <= system.uptime) {
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if (process->wakeupTime() <= system.uptime)
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process->unblock();
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continue;
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}
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continue;
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}
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if (process->state() == Process::BlockedWait) {
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if (!Process::fromPID(process->waitee())) {
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process->unblock();
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continue;
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auto* waitee = Process::fromPID(process->waitee());
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if (!waitee) {
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kprintf("waitee %u of %s(%u) reaped before I could wait?\n", process->waitee(), process->name().characters(), process->pid());
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ASSERT_NOT_REACHED();
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}
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if (waitee->state() == Process::Dead) {
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process->m_waitee_status = (waitee->m_termination_status << 8) | waitee->m_termination_signal;
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process->unblock();
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waitee->set_state(Process::Forgiven);
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}
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continue;
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}
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if (process->state() == Process::BlockedRead) {
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ASSERT(process->m_fdBlockedOnRead != -1);
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if (process->m_file_descriptors[process->m_fdBlockedOnRead]->hasDataAvailableForRead()) {
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if (process->m_file_descriptors[process->m_fdBlockedOnRead]->hasDataAvailableForRead())
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process->unblock();
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continue;
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}
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continue;
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}
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}
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// Forgive dead orphans.
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// FIXME: Does this really make sense?
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for_each_process_in_state(Process::Dead, [] (auto& process) {
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if (!Process::fromPID(process.ppid()))
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process.set_state(Process::Forgiven);
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});
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// Clean up forgiven processes.
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// FIXME: Do we really need this to be a separate pass over the process list?
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for_each_process_in_state(Process::Forgiven, [] (auto& process) {
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s_processes->remove(&process);
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s_deadProcesses->append(&process);
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});
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// Dispatch any pending signals.
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// FIXME: Do we really need this to be a separate pass over the process list?
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for_each_process_not_in_state(Process::Dead, [] (auto& process) {
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if (!process.has_unmasked_pending_signals())
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return;
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process.dispatch_one_pending_signal();
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});
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#ifdef SCHEDULER_DEBUG
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dbgprintf("Scheduler choices:\n");
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for (auto* process = s_processes->head(); process; process = process->next()) {
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@ -1352,11 +1402,11 @@ pid_t Process::sys$waitpid(pid_t waitee, int* wstatus, int options)
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if (!Process::fromPID(waitee))
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return -1;
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m_waitee = waitee;
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m_waiteeStatus = 0;
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m_waitee_status = 0;
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block(BlockedWait);
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sched_yield();
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if (wstatus)
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*wstatus = m_waiteeStatus;
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*wstatus = m_waitee_status;
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return m_waitee;
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}
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