From 8001493df3d3f5c49e39e48c1575f86658302551 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Sat, 22 Apr 2023 15:46:23 +0300
Subject: [PATCH] Kernel: Fix some deadlocks in the Process

---
 kernel/kernel/Process.cpp | 42 ++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index f0824a9c..02a1019a 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -220,20 +220,24 @@ namespace Kernel
 
 	BAN::ErrorOr<size_t> Process::write(int fd, const void* buffer, size_t count)
 	{
-		m_lock.lock();
-		TRY(validate_fd(fd));
-		auto open_fd_copy = open_file_description(fd);
-		m_lock.unlock();
+		OpenFileDescription open_fd_copy;
+
+		{
+			LockGuard _(m_lock);
+			TRY(validate_fd(fd));
+			open_fd_copy = open_file_description(fd);
+		}
 
 		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;
 
-		m_lock.lock();
-		MUST(validate_fd(fd));
-		open_file_description(fd) = open_fd_copy;
-		m_lock.unlock();
+		{
+			LockGuard _(m_lock);
+			MUST(validate_fd(fd));
+			open_file_description(fd) = open_fd_copy;
+		}
 
 		return n_written;
 	}
@@ -266,10 +270,13 @@ namespace Kernel
 
 	BAN::ErrorOr<void> Process::fstat(int fd, struct stat* out)
 	{
-		m_lock.lock();
-		TRY(validate_fd(fd));
-		auto open_fd_copy = open_file_description(fd);
-		m_lock.unlock();
+		OpenFileDescription open_fd_copy;
+
+		{
+			LockGuard _(m_lock);
+			TRY(validate_fd(fd));
+			open_fd_copy = open_file_description(fd);
+		}
 
 		out->st_dev		= open_fd_copy.inode->dev();
 		out->st_ino		= open_fd_copy.inode->ino();
@@ -298,10 +305,13 @@ namespace Kernel
 
 	BAN::ErrorOr<BAN::Vector<BAN::String>> Process::read_directory_entries(int fd)
 	{
-		m_lock.lock();
-		TRY(validate_fd(fd));
-		auto open_fd_copy = open_file_description(fd);
-		m_lock.unlock();
+		OpenFileDescription open_fd_copy;
+
+		{
+			LockGuard _(m_lock);
+			TRY(validate_fd(fd));
+			open_fd_copy = open_file_description(fd);
+		}
 
 		auto result = TRY(open_fd_copy.inode->read_directory_entries(open_fd_copy.offset));
 		open_fd_copy.offset++;