From e60b2a3d2f6d8f5bde6c1eee7d058c7a072f73d7 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Mon, 19 Jun 2023 12:33:25 +0200
Subject: [PATCH] kernel: Move thread exit code into a separate common function

---
 kernel/src/arch/x86_64/CPU.cpp | 40 ++--------------------------------
 kernel/src/sys/exit.cpp        | 17 +--------------
 kernel/src/thread/Thread.cpp   | 22 +++++++++++++++++++
 kernel/src/thread/Thread.h     |  2 ++
 4 files changed, 27 insertions(+), 54 deletions(-)

diff --git a/kernel/src/arch/x86_64/CPU.cpp b/kernel/src/arch/x86_64/CPU.cpp
index c7083ecd..1ac1d957 100644
--- a/kernel/src/arch/x86_64/CPU.cpp
+++ b/kernel/src/arch/x86_64/CPU.cpp
@@ -86,25 +86,7 @@ void decode_page_fault_error_code(u64 code)
     {
         // FIXME: Kill this process with SIGSEGV once we have signals and all that.
         kerrorln("Current task %zu was terminated because of a page fault", Scheduler::current()->id);
-        if (Scheduler::current()->is_kernel) Scheduler::current()->state = ThreadState::Dying;
-        else
-        {
-            auto* current = Scheduler::current();
-            auto* parent = current->parent;
-            if (parent && parent->state == ThreadState::Waiting)
-            {
-                auto child = *parent->child_being_waited_for;
-                if (child == -1 || child == (pid_t)current->id)
-                {
-                    parent->child_being_waited_for = (pid_t)current->id;
-                    parent->wake_up();
-                }
-            }
-            current->state = ThreadState::Exited;
-        }
-        Scheduler::current()->status = 127;
-        kernel_yield();
-        unreachable();
+        Scheduler::current()->exit_and_signal_parent(127);
     }
 
     CPU::efficient_halt();
@@ -122,25 +104,7 @@ void decode_page_fault_error_code(u64 code)
     {
         // FIXME: Kill this process with SIGSEGV once we have signals and all that.
         kerrorln("Current task %zu was terminated because of a general protection fault", Scheduler::current()->id);
-        if (Scheduler::current()->is_kernel) Scheduler::current()->state = ThreadState::Dying;
-        else
-        {
-            auto* current = Scheduler::current();
-            auto* parent = current->parent;
-            if (parent && parent->state == ThreadState::Waiting)
-            {
-                auto child = *parent->child_being_waited_for;
-                if (child == -1 || child == (pid_t)current->id)
-                {
-                    parent->child_being_waited_for = (pid_t)current->id;
-                    parent->wake_up();
-                }
-            }
-            current->state = ThreadState::Exited;
-        }
-        Scheduler::current()->status = 127;
-        kernel_yield();
-        unreachable();
+        Scheduler::current()->exit_and_signal_parent(127);
     }
 
     CPU::efficient_halt();
diff --git a/kernel/src/sys/exit.cpp b/kernel/src/sys/exit.cpp
index 0a6ad43d..558565ff 100644
--- a/kernel/src/sys/exit.cpp
+++ b/kernel/src/sys/exit.cpp
@@ -12,20 +12,5 @@ Result<u64> sys_exit(Registers*, SyscallArgs args)
         return true;
     });
 
-    auto* parent = current->parent;
-    if (parent && parent->state == ThreadState::Waiting)
-    {
-        auto child = *parent->child_being_waited_for;
-        if (child == -1 || child == (pid_t)current->id)
-        {
-            parent->child_being_waited_for = (pid_t)current->id;
-            parent->wake_up();
-        }
-    }
-
-    current->status = status;
-    current->state = ThreadState::Exited;
-
-    kernel_yield();
-    unreachable();
+    current->exit_and_signal_parent(status);
 }
diff --git a/kernel/src/thread/Thread.cpp b/kernel/src/thread/Thread.cpp
index df5e5cd8..24621cc8 100644
--- a/kernel/src/thread/Thread.cpp
+++ b/kernel/src/thread/Thread.cpp
@@ -1,5 +1,6 @@
 #include "thread/Thread.h"
 #include "memory/MemoryManager.h"
+#include "thread/Scheduler.h"
 #include <bits/atfile.h>
 #include <bits/open-flags.h>
 #include <luna/Alloc.h>
@@ -68,6 +69,27 @@ Result<SharedPtr<VFS::Inode>> Thread::resolve_atfile(int dirfd, const String& pa
     return VFS::resolve_path(path.chars(), this->auth, descriptor->inode, follow_last_symlink);
 }
 
+[[noreturn]] void Thread::exit_and_signal_parent(u8 _status)
+{
+    if (is_kernel) state = ThreadState::Dying;
+    else
+    {
+        if (parent && parent->state == ThreadState::Waiting)
+        {
+            auto child = *parent->child_being_waited_for;
+            if (child == -1 || child == (pid_t)id)
+            {
+                parent->child_being_waited_for = (pid_t)id;
+                parent->wake_up();
+            }
+        }
+        state = ThreadState::Exited;
+    }
+    status = _status;
+    kernel_yield();
+    unreachable();
+}
+
 bool FileDescriptor::should_append()
 {
     return flags & O_APPEND;
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
index 7c02dadf..ad6903a6 100644
--- a/kernel/src/thread/Thread.h
+++ b/kernel/src/thread/Thread.h
@@ -99,6 +99,8 @@ struct Thread : public LinkedListNode<Thread>
 
     PageDirectory* directory;
 
+    [[noreturn]] void exit_and_signal_parent(u8 status);
+
     bool is_idle()
     {
         return state == ThreadState::Idle;