From b78edd5eea50fba102c9c73a3c90e6e347e24cb5 Mon Sep 17 00:00:00 2001
From: Amelia Coutard <eliottulio.coutard@gmail.com>
Date: Tue, 14 Mar 2023 16:48:24 +0100
Subject: [PATCH] Encapsulated running the first process into a function

---
 kernel/src/kernel.cpp | 7 +------
 kernel/src/ring3.cpp  | 7 +++++++
 kernel/src/ring3.hpp  | 9 +++++++++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/kernel/src/kernel.cpp b/kernel/src/kernel.cpp
index 244eb1c..014be9a 100644
--- a/kernel/src/kernel.cpp
+++ b/kernel/src/kernel.cpp
@@ -183,11 +183,6 @@ extern "C" void kmain(unsigned long magic, os::phys_ptr<const multiboot2::info_s
 	os::print("Enabling syscalls.\n");
 	os::enable_syscalls();
 
-	os::current_pid = 1;
-	os::get_process(os::current_pid) = test_module_process;
-
-	os::print("Loading test_module virtual memory map.\n");
-	os::paging::load_pml4t(os::get_process(os::current_pid).PML4T);
 	os::print("Moving to ring 3.\n");
-	os::ftl_to_userspace((void*)os::get_process(os::current_pid).rip, (std::byte*)os::get_process(os::current_pid).rsp);
+	os::run_first_process(test_module_process);
 }
diff --git a/kernel/src/ring3.cpp b/kernel/src/ring3.cpp
index aed5e3a..c0f58bd 100644
--- a/kernel/src/ring3.cpp
+++ b/kernel/src/ring3.cpp
@@ -16,6 +16,13 @@
 #include "serial.hpp"
 #include "paging.hpp"
 
+void os::run_first_process(os::process& process) {
+	os::current_pid = 1;
+	os::get_process(os::current_pid) = process;
+	os::paging::load_pml4t(process.PML4T);
+	os::ftl_to_userspace((void*)process.rip, (std::byte*)process.rsp);
+}
+
 void os::set_ring0_stack(os::tss& tss, std::uint64_t stack) {
 	tss.rsp0 = stack;
 }
diff --git a/kernel/src/ring3.hpp b/kernel/src/ring3.hpp
index ab77686..18cb4cb 100644
--- a/kernel/src/ring3.hpp
+++ b/kernel/src/ring3.hpp
@@ -37,7 +37,10 @@ struct __attribute__((packed)) tss {
 	std::uint16_t iopb;
 };
 
+struct process;
+
 extern "C" void ftl_to_userspace(void* program, std::byte* stack);
+void run_first_process(process& process);
 extern "C" void load_tss();
 extern "C" void syscall_64bit_handler();
 
@@ -69,11 +72,17 @@ inline process& get_process(std::uint64_t pid) {
 	os::assert(1 <= pid && pid <= 2048, "Invalid pid: {}.\n", pid);
 	return ((process*)0xFFFF'C000'0000'0000)[pid - 1];
 }
+inline bool process_exists(std::uint64_t pid) {
+	return 1 <= pid && pid <= 2048 && get_process(pid).rsp != 0;
+}
 inline port& get_port(std::uint64_t pid, std::uint64_t port) {
 	os::assert(1 <= pid && pid <= 2048, "Invalid pid: {}.\n", pid);
 	os::assert(1 <= port && port <= 4096, "Invalid port: {}.\n", pid);
 	return ((os::port*)0xFFFF'C000'0001'0000)[(pid - 1) * 4096 + (port - 1)];
 }
+inline bool port_exists(std::uint64_t pid, std::uint64_t port) {
+	return process_exists(pid) && 1 <= port && port <= 4096 && get_port(pid, port).other_pid != 0;
+}
 
 extern std::uint64_t current_pid;
 
-- 
2.47.0