From ff770b73288ad07f88cd3a0965a40e6fddc784ad Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Fri, 10 Mar 2023 21:09:08 +0100
Subject: [PATCH] VFS+TmpFS: Add support for creating subdirectories (mkdir)

---
 kernel/src/fs/VFS.h                |  7 +++++++
 kernel/src/fs/tmpfs/FileSystem.cpp | 13 +++++++++++++
 kernel/src/fs/tmpfs/FileSystem.h   |  8 ++++++++
 kernel/src/main.cpp                | 14 ++++++++++++--
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/kernel/src/fs/VFS.h b/kernel/src/fs/VFS.h
index 70e2fb12..ea065ddb 100644
--- a/kernel/src/fs/VFS.h
+++ b/kernel/src/fs/VFS.h
@@ -19,6 +19,8 @@ namespace VFS
 
         virtual Result<SharedPtr<Inode>> create_file(const char* name) = 0;
 
+        virtual Result<SharedPtr<Inode>> create_subdirectory(const char* name) = 0;
+
         // Generic methods
         virtual FileSystem& fs() const = 0;
 
@@ -42,6 +44,11 @@ namespace VFS
             return err(ENOTDIR);
         }
 
+        Result<SharedPtr<Inode>> create_subdirectory(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 b0f2df99..64dae8a0 100644
--- a/kernel/src/fs/tmpfs/FileSystem.cpp
+++ b/kernel/src/fs/tmpfs/FileSystem.cpp
@@ -26,13 +26,17 @@ namespace TmpFS
     Result<SharedPtr<VFS::Inode>> FileSystem::create_dir_inode(SharedPtr<VFS::Inode> parent)
     {
         SharedPtr<DirInode> inode = TRY(make_shared<DirInode>());
+
         TRY(inode->add_entry(inode, "."));
         TRY(inode->add_entry(parent ? parent : (SharedPtr<VFS::Inode>)inode, ".."));
 
+        inode->set_self(inode, {});
         inode->set_fs(*this, {});
         inode->set_inode_number(m_next_inode_number, {});
+
         TRY(m_inodes.try_append(inode));
         m_next_inode_number++;
+
         return (SharedPtr<VFS::Inode>)inode;
     }
 
@@ -68,4 +72,13 @@ namespace TmpFS
 
         return inode;
     }
+
+    Result<SharedPtr<VFS::Inode>> DirInode::create_subdirectory(const char* name)
+    {
+        auto inode = TRY(m_fs->create_dir_inode(m_self));
+
+        TRY(add_entry(inode, name));
+
+        return inode;
+    }
 }
diff --git a/kernel/src/fs/tmpfs/FileSystem.h b/kernel/src/fs/tmpfs/FileSystem.h
index 6e1e5f39..6212daea 100644
--- a/kernel/src/fs/tmpfs/FileSystem.h
+++ b/kernel/src/fs/tmpfs/FileSystem.h
@@ -80,6 +80,11 @@ namespace TmpFS
             m_inode_number = inum;
         }
 
+        void set_self(SharedPtr<VFS::Inode> self, Badge<FileSystem>)
+        {
+            m_self = self;
+        }
+
         Result<SharedPtr<VFS::Inode>> find(const char* name) const override;
 
         VFS::FileSystem& fs() const override
@@ -98,6 +103,7 @@ namespace TmpFS
         }
 
         Result<SharedPtr<VFS::Inode>> create_file(const char* name) override;
+        Result<SharedPtr<VFS::Inode>> create_subdirectory(const char* name) override;
 
         Result<void> add_entry(SharedPtr<VFS::Inode> inode, const char* name);
 
@@ -107,6 +113,8 @@ namespace TmpFS
         VFS::FileSystem* m_fs;
         usize m_inode_number;
 
+        SharedPtr<VFS::Inode> m_self;
+
         struct Entry
         {
             SharedPtr<VFS::Inode> inode;
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index 92f11c0a..b015f611 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -52,14 +52,24 @@ static Result<void> try_init_vfs()
     VFS::root_fs = TRY(TmpFS::FileSystem::create());
 
     VFS::Inode& root_inode = VFS::root_inode();
+
     kinfoln("root inode number: %zu", root_inode.inode_number());
 
     kinfoln("root inode's '.' entry inode number: %zu", TRY(root_inode.find("."))->inode_number());
     kinfoln("root inode's '..' entry inode number: %zu", TRY(root_inode.find(".."))->inode_number());
 
-    TRY(root_inode.create_file("usr"));
+    TRY(root_inode.create_subdirectory("etc"));
 
-    kinfoln("root inode's 'usr' entry inode number: %zu", TRY(root_inode.find("usr"))->inode_number());
+    kinfoln("root inode's 'etc' entry inode number: %zu", TRY(root_inode.find("etc"))->inode_number());
+
+    auto& etc = *TRY(root_inode.find("etc"));
+
+    kinfoln("etc inode's '.' entry inode number: %zu", TRY(etc.find("."))->inode_number());
+    kinfoln("etc inode's '..' entry inode number: %zu", TRY(etc.find(".."))->inode_number());
+
+    TRY(etc.create_file("passwd"));
+
+    kinfoln("etc inode's 'passwd' entry inode number: %zu", TRY(etc.find("passwd"))->inode_number());
 
     return {};
 }