From df128821b2ca675a47a86439f1fd0ad33bed737e Mon Sep 17 00:00:00 2001
From: Sergey Bugaev <bugaevc@serenityos.org>
Date: Wed, 27 May 2020 00:37:27 +0300
Subject: [PATCH] Kernel: Introduce "boot_mode" and "init" cmdline options

Together, they replace the old text_debug option.

* boot_mode should be either "graphical" (the default) or "text". We could
  potentially support other values here in the future.
* init specifies which userspace process the kernel should spawn to bootstrap
  userspace. By default, this is SystemServer, but you can specify e.g.
  init=/bin/Shell to run system diagnostics.
---
 Kernel/init.cpp | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index 68f60bcf5b..9909b20ec2 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -168,7 +168,9 @@ void init_stage2()
 
     PCI::initialize();
 
-    if (kernel_command_line().contains("text_debug")) {
+    bool text_mode = kernel_command_line().lookup("boot_mode").value_or("graphical") == "text";
+
+    if (text_mode) {
         dbg() << "Text mode enabled";
     } else {
         bool bxvga_found = false;
@@ -213,7 +215,6 @@ void init_stage2()
         DMIDecoder::initialize();
     }
 
-    bool text_debug = kernel_command_line().contains("text_debug");
     bool force_pio = kernel_command_line().contains("force_pio");
 
     auto root = kernel_command_line().lookup("root").value_or("/dev/hda");
@@ -302,28 +303,16 @@ void init_stage2()
 
     int error;
 
-    // SystemServer will start WindowServer, which will be doing graphics.
-    // From this point on we don't want to touch the VGA text terminal or
-    // accept keyboard input.
-    if (text_debug) {
-        tty0->set_graphical(false);
-        Thread* thread = nullptr;
-        Process::create_user_process(thread, "/bin/Shell", (uid_t)0, (gid_t)0, (pid_t)0, error, {}, {}, tty0);
-        if (error != 0) {
-            klog() << "init_stage2: error spawning Shell: " << error;
-            hang();
-        }
-        thread->set_priority(THREAD_PRIORITY_HIGH);
-    } else {
-        tty0->set_graphical(true);
-        Thread* thread = nullptr;
-        Process::create_user_process(thread, "/bin/SystemServer", (uid_t)0, (gid_t)0, (pid_t)0, error, {}, {}, tty0);
-        if (error != 0) {
-            klog() << "init_stage2: error spawning SystemServer: " << error;
-            hang();
-        }
-        thread->set_priority(THREAD_PRIORITY_HIGH);
+    // FIXME: It would be nicer to set the mode from userspace.
+    tty0->set_graphical(!text_mode);
+    Thread* thread = nullptr;
+    auto userspace_init = kernel_command_line().lookup("init").value_or("/bin/SystemServer");
+    Process::create_user_process(thread, userspace_init, (uid_t)0, (gid_t)0, (pid_t)0, error, {}, {}, tty0);
+    if (error != 0) {
+        klog() << "init_stage2: error spawning SystemServer: " << error;
+        hang();
     }
+    thread->set_priority(THREAD_PRIORITY_HIGH);
 
     NetworkTask::spawn();