From db076058b9e82e4efb2afc641911e0a60a5354b6 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Wed, 5 Apr 2023 01:10:25 +0300
Subject: [PATCH] Kernel: Process can now initialize stdio

This allows the use of the fds STD{IN,OUT,ERR}_FILENO
---
 kernel/include/kernel/Process.h |  2 ++
 kernel/kernel/Process.cpp       | 14 ++++++++++++--
 kernel/kernel/kernel.cpp        |  8 +++++---
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 3227da221..4762abb3d 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -27,6 +27,8 @@ namespace Kernel
 		BAN::ErrorOr<void> add_thread(entry_t, void*);
 		void on_thread_exit(Thread&);
 
+		BAN::ErrorOr<void> init_stdio();
+
 		pid_t pid() const { return m_pid; }
 
 		BAN::ErrorOr<int> open(BAN::StringView, int);
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index d3058aaf6..923722425 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -18,6 +18,16 @@ namespace Kernel
 		return process;
 	}
 
+	BAN::ErrorOr<void> Process::init_stdio()
+	{
+		if (!m_open_files.empty())
+			return BAN::Error::from_c_string("Could not init stdio, process already has open files");
+		TRY(open("/dev/tty1", O_RDONLY)); // stdin
+		TRY(open("/dev/tty1", O_WRONLY)); // stdout
+		TRY(open("/dev/tty1", O_WRONLY)); // stderr
+		return {};
+	}
+
 	BAN::ErrorOr<void> Process::add_thread(entry_t entry, void* data)
 	{
 		Thread* thread = TRY(Thread::create(entry, data, this));
@@ -43,7 +53,7 @@ namespace Kernel
 
 	BAN::ErrorOr<int> Process::open(BAN::StringView path, int flags)
 	{
-		if (flags != O_RDONLY)
+		if (flags & ~O_RDWR)
 			return BAN::Error::from_errno(ENOTSUP);
 
 		BAN::String absolute_path = TRY(absolute_path_of(path));
@@ -97,7 +107,7 @@ namespace Kernel
 		auto open_fd_copy = open_file_description(fd);
 		m_lock.unlock();
 
-		if (!(open_fd_copy.flags & O_RDONLY))
+		if (!(open_fd_copy.flags & O_WRONLY))
 			return BAN::Error::from_errno(EBADF);
 		size_t n_written = TRY(open_fd_copy.inode->write(open_fd_copy.offset, buffer, count));
 		open_fd_copy.offset += n_written;
diff --git a/kernel/kernel/kernel.cpp b/kernel/kernel/kernel.cpp
index 0fde0d7f4..8a85b73fd 100644
--- a/kernel/kernel/kernel.cpp
+++ b/kernel/kernel/kernel.cpp
@@ -22,6 +22,8 @@
 #include <kernel/Terminal/TTY.h>
 #include <kernel/Terminal/VesaTerminalDriver.h>
 
+#include <unistd.h>
+
 extern "C" const char g_kernel_cmdline[];
 
 struct ParsedCommandLine
@@ -223,12 +225,12 @@ static void init2(void* terminal_driver)
 	MUST(Process::create_kernel(
 		[](void*)
 		{
-			int fd = MUST(Process::current()->open("/dev/tty1", 1));
+			MUST(Process::current()->init_stdio());
 			while (true)
 			{
 				char buffer[1024];
-				int n_read = MUST(Process::current()->read(fd, buffer, sizeof(buffer)));
-				MUST(Process::current()->write(fd, buffer, n_read));
+				int n_read = MUST(Process::current()->read(STDIN_FILENO, buffer, sizeof(buffer)));
+				MUST(Process::current()->write(STDOUT_FILENO, buffer, n_read));
 				dprintln("{} bytes", n_read);
 			}
 		}, nullptr