From 0e6ce349fa6b8b46157dd5aa5f6a55d5af809896 Mon Sep 17 00:00:00 2001
From: pjht <pterpstra@pterpstra.com>
Date: Mon, 23 Sep 2024 13:25:37 -0500
Subject: [PATCH] Make new processes start sleeping

---
 src/interrupts.rs | 34 ++++++++++++++++++----------------
 src/main.rs       |  5 +++--
 src/tasking.rs    | 18 ++++++++++++------
 3 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/src/interrupts.rs b/src/interrupts.rs
index c274b24..52222a3 100644
--- a/src/interrupts.rs
+++ b/src/interrupts.rs
@@ -188,14 +188,11 @@ fn irq_handler(_stack_frame: InterruptStackFrame, index: u8, _error_code: Option
                 clippy::unwrap_used,
                 reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
             )]
-            let sleep_status = TASKING.proc_sleeping(pid).unwrap();
-            if sleep_status == Some(SleepReason::WaitingForIPC) {
-                #[expect(
-                    clippy::unwrap_used,
-                    reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
-                )]
-                TASKING.wake(pid).unwrap();
-            }
+            #[expect(
+                clippy::unwrap_used,
+                reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
+            )]
+            TASKING.wake(pid, SleepReason::WaitingForIPC).unwrap();
         } else {
             println!("irq 1 msg: Bad PID ({})", pid);
         }
@@ -549,14 +546,11 @@ extern "C" fn syscall_handler() {
                         clippy::unwrap_used,
                         reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
                     )]
-                    let sleep_status = TASKING.proc_sleeping(pid).unwrap();
-                    if sleep_status == Some(SleepReason::WaitingForIPC) {
-                        #[expect(
-                            clippy::unwrap_used,
-                            reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
-                        )]
-                        TASKING.wake(pid).unwrap();
-                    }
+                    #[expect(
+                        clippy::unwrap_used,
+                        reason = "The PID is known valid due to using it in message_queue_mut in the if-let condition"
+                    )]
+                    TASKING.wake(pid, SleepReason::WaitingForIPC).unwrap();
                     retval = 0;
                 } else {
                     println!("ipc_send: Bad PID ({})", pid);
@@ -752,6 +746,14 @@ extern "C" fn syscall_handler() {
                 retval = 1;
             }
         }
+        24 => {
+            let pid = usize(regs.rcx);
+            if TASKING.wake(pid, SleepReason::NewProcess).is_err() {
+                retval = 1;
+            } else {
+                retval = 0;
+            }
+        }
         _ => (),
     };
     unsafe { SYSCALL_REGS = regs };
diff --git a/src/main.rs b/src/main.rs
index 78d5725..3d060ec 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -102,7 +102,7 @@ use physical_memory::PHYSICAL_MEMORY;
 use serial::SECOND_PORT;
 use spin::lazy::Lazy;
 use tar_no_std::TarArchiveRef;
-use tasking::TASKING;
+use tasking::{SleepReason, TASKING};
 use virtual_memory::{ACTIVE_SPACE, KERNEL_SPACE};
 use x86_64::{
     registers::rflags::{self, RFlags},
@@ -290,11 +290,12 @@ pub fn main() {
         clippy::unwrap_used,
         reason = "Argument does not contain a null byte, thus this cannot panic"
     )]
-    TASKING
+    let init_pid = TASKING
         .new_process(
             ptr::with_exposed_provenance(usize(init.ehdr.e_entry)),
             init_addr_space,
             &[&CString::new(b"init").unwrap()],
         )
         .expect("Failed to create init process");
+    TASKING.wake(init_pid, SleepReason::NewProcess).unwrap();
 }
diff --git a/src/tasking.rs b/src/tasking.rs
index 952bab3..30a95e3 100644
--- a/src/tasking.rs
+++ b/src/tasking.rs
@@ -85,6 +85,7 @@ extern "C" fn task_init() {
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum SleepReason {
     WaitingForIPC,
+    NewProcess,
 }
 
 #[derive(Debug)]
@@ -203,10 +204,10 @@ impl Tasking {
             address_spaces: Mutex::new(Slab::new()),
             data_buffers: Mutex::new(Slab::new()),
             message_queue: Mutex::new(SegQueue::new()),
-            sleeping: RwLock::new(None),
+            sleeping: RwLock::new(Some(SleepReason::NewProcess)),
             arguments: (user_arg_mem.cast(), arguments.len()),
         });
-        self.ready_to_run.lock().push_back(pid);
+        //self.ready_to_run.lock().push_back(pid);
         Ok(pid)
     }
 
@@ -394,10 +395,15 @@ impl Tasking {
         self.task_yield();
     }
 
-    pub fn wake(&self, pid: usize) -> Result<(), InvalidPid> {
-        *self.processes.read().get(pid).ok_or(InvalidPid)?.sleeping.write() = None;
-        if Some(pid) != self.current_pid() {
-            self.ready_to_run.lock().push_back(pid);
+    pub fn wake(&self, pid: usize, reason: SleepReason) -> Result<(), InvalidPid> {
+        let processes = self.processes.read();
+        let process = processes.get(pid).ok_or(InvalidPid)?;
+        let mut sleeping = process.sleeping.write();
+        if *sleeping == Some(reason) {
+            if Some(pid) != self.current_pid() {
+                self.ready_to_run.lock().push_back(pid);
+            }
+            *sleeping = None;
         }
         Ok(())
     }