:github_url: https://github.com/nyx-org/gaia


.. _program_listing_file_fs_devfs.hpp:

Program Listing for File devfs.hpp
==================================

|exhale_lsh| :ref:`Return to documentation for file <file_fs_devfs.hpp>` (``fs/devfs.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /* SPDX-License-Identifier: BSD-2-Clause */
   #pragma once
   #include <frg/array.hpp>
   #include <fs/vfs.hpp>
   #include <lib/list.hpp>
   
   #define MINORBITS 20
   #define MINORMASK ((1U << MINORBITS) - 1)
   
   #define MINOR(dev) ((unsigned int)((dev) >> MINORBITS))
   #define MAJOR(dev) ((unsigned int)((dev)&MINORMASK))
   #define MAKEDEV(ma, mi) (((mi) << MINORBITS) | (ma))
   
   // Pretty much the same thing as tmpfs, but for devices
   namespace Gaia::Fs {
   
   class Devfs : public VnodeOps {
   public:
     Result<size_t, Error> write(Vnode *vn, frg::span<uint8_t> buf,
                                 off_t off) override;
   
     Result<size_t, Error> read(Vnode *vn, frg::span<uint8_t> buf,
                                off_t off) override;
   
     Result<Vnode *, Error> create(Vnode *cwd, frg::string_view name,
                                   VnodeAttr attr, dev_t dev) override;
   
     Result<Vnode *, Error> link(Vnode *cwd, frg::string_view path,
                                 frg::string_view link, VnodeAttr attr) override;
   
     Result<Vnode *, Error> lookup(Vnode *cwd, frg::string_view name) override;
   
     Result<Vnode *, Error> mkdir(Vnode *dir, frg::string_view name,
                                  VnodeAttr attr) override;
   
     Result<uint64_t, Error> ioctl(Vnode *node, uint64_t request,
                                   void *arg) override;
   
     Result<VnodeAttr, Error> getattr(Vnode *node) override;
   
     Vm::String get_absolute_path(Vnode *node) override;
   
     Result<size_t, Error> readdir(Vnode *vn, void *buf, size_t max_size,
                                   off_t offset) override;
   };
   
   class DeviceOps {
   public:
     virtual Result<size_t, Error> write(dev_t minor, frg::span<uint8_t> buf,
                                         off_t off) = 0;
   
     virtual Result<size_t, Error> read(dev_t minor, frg::span<uint8_t> buf,
                                        off_t off) = 0;
   
     virtual Result<uint64_t, Error> ioctl(dev_t minor, uint64_t request,
                                           void *arg) = 0;
   
     virtual Result<VnodeAttr, Error> getattr(dev_t minor) = 0;
     // TODO: mmap
   };
   
   Result<dev_t, Error> dev_alloc_major(DeviceOps *ops);
   
   void devfs_init();
   
   Devfs *get_devfs();
   
   } // namespace Gaia::Fs