From 41c7e3780d56dfa6638274512370a7ab26a04004 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Thu, 23 Mar 2023 22:25:56 +0100
Subject: [PATCH] kernel: Add support for exit codes and start preparing for
 waitpid()

---
 kernel/src/sys/exit.cpp    | 11 +++++++++--
 kernel/src/thread/Thread.h |  3 +++
 libc/include/stdlib.h      |  4 ++--
 libc/src/stdlib.cpp        |  6 +++---
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/kernel/src/sys/exit.cpp b/kernel/src/sys/exit.cpp
index adc591c1..5d02f321 100644
--- a/kernel/src/sys/exit.cpp
+++ b/kernel/src/sys/exit.cpp
@@ -1,7 +1,14 @@
 #include "sys/Syscall.h"
 #include "thread/Scheduler.h"
 
-Result<u64> sys_exit(Registers*, SyscallArgs)
+Result<u64> sys_exit(Registers*, SyscallArgs args)
 {
-    kernel_exit();
+    u8 status = (u8)args[0];
+
+    Thread* current = Scheduler::current();
+
+    current->status = status;
+    current->state = ThreadState::Exited;
+
+    kernel_yield();
 }
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
index 89f81710..3d637f77 100644
--- a/kernel/src/thread/Thread.h
+++ b/kernel/src/thread/Thread.h
@@ -19,6 +19,7 @@ enum class ThreadState
     Idle,
     Runnable,
     Sleeping,
+    Exited,
     Dying
 };
 
@@ -64,6 +65,8 @@ struct Thread : public LinkedListNode<Thread>
 
     bool is_kernel { true };
 
+    u8 status { 0 };
+
     PageDirectory* directory;
 
     bool is_idle()
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 1c31d81c..3799a971 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -95,10 +95,10 @@ extern "C"
     void srand(int);
 
     /* Exit the program normally, performing any registered cleanup actions. */
-    __noreturn void exit(int);
+    __noreturn void exit(int status);
 
     /* Exit the program abnormally, without performing any registered cleanup actions. */
-    __noreturn void _Exit(int);
+    __noreturn void _Exit(int status);
 
     int system(const char*);
 
diff --git a/libc/src/stdlib.cpp b/libc/src/stdlib.cpp
index 9bd77c6f..6a880851 100644
--- a/libc/src/stdlib.cpp
+++ b/libc/src/stdlib.cpp
@@ -94,13 +94,13 @@ extern "C"
 
     __noreturn void abort()
     {
-        syscall(SYS_exit);
+        syscall(SYS_exit, 255);
         __builtin_unreachable();
     }
 
-    __noreturn void _Exit(int)
+    __noreturn void _Exit(int status)
     {
-        syscall(SYS_exit);
+        syscall(SYS_exit, status);
         __builtin_unreachable();
     }