Kernel: Make major and minor numbers to be DistinctNumerics

This helps avoid confusion in general, and make constructors, methods
and code patterns much more clean and understandable.

4 files changed, 31 insertions, 14 deletions

diff --git a/Kernel/FileSystem/DevTmpFS.cpp b/Kernel/FileSystem/DevTmpFS.cpp
index 26cb558b2d..420ccf4ca3 100644
--- a/Kernel/FileSystem/DevTmpFS.cpp
+++ b/Kernel/FileSystem/DevTmpFS.cpp
@@ -48,7 +48,7 @@ DevTmpFSInode::DevTmpFSInode(DevTmpFS& fs)
 {
 }
 
-DevTmpFSInode::DevTmpFSInode(DevTmpFS& fs, unsigned major_number, unsigned minor_number)
+DevTmpFSInode::DevTmpFSInode(DevTmpFS& fs, MajorNumber major_number, MinorNumber minor_number)
     : Inode(fs, fs.allocate_inode_index())
     , m_major_number(major_number)
     , m_minor_number(minor_number)
@@ -263,8 +263,8 @@ ErrorOr<NonnullRefPtr<Inode>> DevTmpFSDirectoryInode::create_child(StringView na
     }
     if (metadata.is_device()) {
         auto name_kstring = TRY(KString::try_create(name));
-        unsigned major = major_from_encoded_device(device_mode);
-        unsigned minor = minor_from_encoded_device(device_mode);
+        auto major = major_from_encoded_device(device_mode);
+        auto minor = minor_from_encoded_device(device_mode);
         auto new_device_inode = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) DevTmpFSDeviceInode(fs(), major, minor, is_block_device(mode), move(name_kstring))));
         TRY(new_device_inode->chmod(mode));
         m_nodes.append(*new_device_inode);
@@ -298,7 +298,7 @@ ErrorOr<void> DevTmpFSRootDirectoryInode::chown(UserID, GroupID)
     return EPERM;
 }
 
-DevTmpFSDeviceInode::DevTmpFSDeviceInode(DevTmpFS& fs, unsigned major_number, unsigned minor_number, bool block_device, NonnullOwnPtr<KString> name)
+DevTmpFSDeviceInode::DevTmpFSDeviceInode(DevTmpFS& fs, MajorNumber major_number, MinorNumber minor_number, bool block_device, NonnullOwnPtr<KString> name)
     : DevTmpFSInode(fs, major_number, minor_number)
     , m_name(move(name))
     , m_block_device(block_device)
diff --git a/Kernel/FileSystem/DevTmpFS.h b/Kernel/FileSystem/DevTmpFS.h
index 1c8599461b..c3d872fc4a 100644
--- a/Kernel/FileSystem/DevTmpFS.h
+++ b/Kernel/FileSystem/DevTmpFS.h
@@ -47,7 +47,7 @@ public:
 
 protected:
     explicit DevTmpFSInode(DevTmpFS&);
-    DevTmpFSInode(DevTmpFS&, unsigned, unsigned);
+    DevTmpFSInode(DevTmpFS&, MajorNumber, MinorNumber);
     virtual ErrorOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
     virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
     virtual ErrorOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
@@ -64,8 +64,8 @@ protected:
     mode_t m_mode { 0600 };
     UserID m_uid { 0 };
     GroupID m_gid { 0 };
-    const unsigned m_major_number { 0 };
-    const unsigned m_minor_number { 0 };
+    const MajorNumber m_major_number { 0 };
+    const MinorNumber m_minor_number { 0 };
 
     enum class Type {
         BlockDevice,
@@ -90,7 +90,7 @@ public:
     virtual ~DevTmpFSDeviceInode() override;
 
 private:
-    DevTmpFSDeviceInode(DevTmpFS&, unsigned, unsigned, bool, NonnullOwnPtr<KString> name);
+    DevTmpFSDeviceInode(DevTmpFS&, MajorNumber, MinorNumber, bool, NonnullOwnPtr<KString> name);
     // ^DevTmpFSInode
     virtual Type node_type() const override { return m_block_device ? Type::BlockDevice : Type::CharacterDevice; }
 
diff --git a/Kernel/FileSystem/DeviceFileTypes.h b/Kernel/FileSystem/DeviceFileTypes.h
new file mode 100644
index 0000000000..aba01e973b
--- /dev/null
+++ b/Kernel/FileSystem/DeviceFileTypes.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+namespace Kernel {
+
+TYPEDEF_DISTINCT_ORDERED_ID(unsigned, MajorNumber);
+TYPEDEF_DISTINCT_ORDERED_ID(unsigned, MinorNumber);
+
+}
diff --git a/Kernel/FileSystem/InodeMetadata.h b/Kernel/FileSystem/InodeMetadata.h
index 95bfba8367..1dc23b6d72 100644
--- a/Kernel/FileSystem/InodeMetadata.h
+++ b/Kernel/FileSystem/InodeMetadata.h
@@ -8,6 +8,7 @@
 
 #include <AK/Error.h>
 #include <AK/Span.h>
+#include <Kernel/FileSystem/DeviceFileTypes.h>
 #include <Kernel/FileSystem/InodeIdentifier.h>
 #include <Kernel/Forward.h>
 #include <Kernel/UnixTypes.h>
@@ -16,12 +17,12 @@ namespace Kernel {
 
 class Process;
 
-constexpr u32 encoded_device(unsigned major, unsigned minor)
+constexpr u64 encoded_device(MajorNumber major, MinorNumber minor)
 {
-    return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
+    return (minor.value() & 0xff) | (major.value() << 8) | ((minor.value() & ~0xff) << 12);
 }
-static inline unsigned int major_from_encoded_device(dev_t dev) { return (dev & 0xfff00u) >> 8u; }
-static inline unsigned int minor_from_encoded_device(dev_t dev) { return (dev & 0xffu) | ((dev >> 12u) & 0xfff00u); }
+static inline MajorNumber major_from_encoded_device(dev_t dev) { return (dev & 0xfff00u) >> 8u; }
+static inline MinorNumber minor_from_encoded_device(dev_t dev) { return (dev & 0xffu) | ((dev >> 12u) & 0xfff00u); }
 
 inline bool is_directory(mode_t mode) { return (mode & S_IFMT) == S_IFDIR; }
 inline bool is_character_device(mode_t mode) { return (mode & S_IFMT) == S_IFCHR; }
@@ -122,8 +123,8 @@ struct InodeMetadata {
     time_t dtime { 0 };
     blkcnt_t block_count { 0 };
     blksize_t block_size { 0 };
-    unsigned major_device { 0 };
-    unsigned minor_device { 0 };
+    MajorNumber major_device { 0 };
+    MinorNumber minor_device { 0 };
 };
 
 }