From 5b43345b7d441facf2ab1a40492ec97d5e7c61c0 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 25 Feb 2023 19:22:05 +0100
Subject: [PATCH] kernel: Implement creating file inodes in tmpfs directories

---
 kernel/src/fs/VFS.h                |  9 +++++++++
 kernel/src/fs/tmpfs/FileSystem.cpp | 28 ++++++++++++++++++++++++++--
 kernel/src/fs/tmpfs/FileSystem.h   | 13 +++++++++++++
 kernel/src/main.cpp                |  3 +++
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/kernel/src/fs/VFS.h b/kernel/src/fs/VFS.h
index 92c4d98e..9c89f273 100644
--- a/kernel/src/fs/VFS.h
+++ b/kernel/src/fs/VFS.h
@@ -14,8 +14,12 @@ namespace VFS
     class Inode
     {
       public:
+        // Directory-specific methods
         virtual Result<SharedPtr<Inode>> find(const char* name) const = 0;
 
+        virtual Result<SharedPtr<Inode>> create_file(const char* name) = 0;
+
+        // Generic methods
         virtual FileSystem& fs() const = 0;
 
         virtual ~Inode() = default;
@@ -33,6 +37,11 @@ namespace VFS
             return err(ENOTDIR);
         }
 
+        Result<SharedPtr<Inode>> create_file(const char*) override
+        {
+            return err(ENOTDIR);
+        }
+
         InodeType type() const override
         {
             return InodeType::RegularFile;
diff --git a/kernel/src/fs/tmpfs/FileSystem.cpp b/kernel/src/fs/tmpfs/FileSystem.cpp
index 3d55ffa7..4606743e 100644
--- a/kernel/src/fs/tmpfs/FileSystem.cpp
+++ b/kernel/src/fs/tmpfs/FileSystem.cpp
@@ -25,6 +25,8 @@ namespace TmpFS
     Result<SharedPtr<VFS::Inode>> FileSystem::create_dir_inode()
     {
         SharedPtr<DirInode> inode = TRY(make_shared<DirInode>());
+        TRY(inode->add_entry(inode, "."));
+
         inode->set_fs(*this, {});
         inode->set_inode_number(m_next_inode_number, {});
         TRY(m_inodes.try_append(inode));
@@ -39,7 +41,29 @@ namespace TmpFS
 
     Result<SharedPtr<VFS::Inode>> DirInode::find(const char* name) const
     {
-        ignore(name);
-        todo();
+        for (const auto& entry : m_entries)
+        {
+            if (!strcmp(name, entry.name.chars())) return entry.inode;
+        }
+
+        return err(ENOENT);
+    }
+
+    Result<void> DirInode::add_entry(SharedPtr<VFS::Inode> inode, const char* name)
+    {
+        Entry entry = { inode, TRY(OwnedStringView::from_string_literal(name)) };
+
+        TRY(m_entries.try_append(move(entry)));
+
+        return {};
+    }
+
+    Result<SharedPtr<VFS::Inode>> DirInode::create_file(const char* name)
+    {
+        auto inode = TRY(m_fs->create_file_inode());
+
+        TRY(add_entry(inode, name));
+
+        return inode;
     }
 }
diff --git a/kernel/src/fs/tmpfs/FileSystem.h b/kernel/src/fs/tmpfs/FileSystem.h
index c6ac85ae..044a26a5 100644
--- a/kernel/src/fs/tmpfs/FileSystem.h
+++ b/kernel/src/fs/tmpfs/FileSystem.h
@@ -2,6 +2,7 @@
 #include "fs/VFS.h"
 #include <luna/Atomic.h>
 #include <luna/Badge.h>
+#include <luna/OwnedStringView.h>
 #include <luna/Vector.h>
 
 namespace TmpFS
@@ -96,10 +97,22 @@ namespace TmpFS
             return VFS::InodeType::Directory;
         }
 
+        Result<SharedPtr<VFS::Inode>> create_file(const char* name) override;
+
+        Result<void> add_entry(SharedPtr<VFS::Inode> inode, const char* name);
+
         virtual ~DirInode() = default;
 
       private:
         VFS::FileSystem* m_fs;
         usize m_inode_number;
+
+        struct Entry
+        {
+            SharedPtr<VFS::Inode> inode;
+            OwnedStringView name;
+        };
+
+        Vector<Entry> m_entries;
     };
 }
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index b65c997d..3427cf6e 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -61,6 +61,9 @@ Result<void> init()
     VFS::Inode& root_inode = VFS::root_inode();
     kinfoln("root inode number: %zu", root_inode.inode_number());
 
+    TRY(root_inode.create_file("usr"));
+    kinfoln("root inode's 'usr' entry inode number: %zu", TRY(root_inode.find("usr"))->inode_number());
+
     TarStream::Entry entry;
     while (TRY(g_initrd.read_next_entry(entry)))
     {