Kernel/USB: Move USB bus information from /proc to /sys

This patch moves all the USB data from /proc/bus/usb to /sys/bus/usb.

Kernel/Bus/USB/UHCIController.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2020, Jesse Buhagiar <jooster669@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -12,9 +12,9 @@
 #include <Kernel/Bus/USB/USBRequest.h>
 #include <Kernel/CommandLine.h>
 #include <Kernel/Debug.h>
+#include <Kernel/FileSystem/SysFS.h>
 #include <Kernel/KBufferBuilder.h>
 #include <Kernel/Process.h>
-#include <Kernel/ProcessExposed.h>
 #include <Kernel/Sections.h>
 #include <Kernel/StdLib.h>
 #include <Kernel/Time/TimeManagement.h>
@@ -69,29 +69,29 @@ static constexpr u16 UHCI_PORTSC_SUSPEND = 0x1000;
 static constexpr u8 UHCI_NUMBER_OF_ISOCHRONOUS_TDS = 128;
 static constexpr u16 UHCI_NUMBER_OF_FRAMES = 1024;
 
-class ProcFSUSBBusDirectory;
+class SysFSUSBBusDirectory;
-static ProcFSUSBBusDirectory* s_procfs_usb_bus_directory;
+static SysFSUSBBusDirectory* s_procfs_usb_bus_directory;
 
-class ProcFSUSBDeviceInformation : public ProcFSGlobalInformation {
+class SysFSUSBDeviceInformation : public SysFSComponent {
-    friend class ProcFSUSBBusDirectory;
+    friend class SysFSUSBBusDirectory;
 
 public:
-    virtual ~ProcFSUSBDeviceInformation() override {};
+    virtual ~SysFSUSBDeviceInformation() override {};
 
-    static NonnullRefPtr<ProcFSUSBDeviceInformation> create(USB::Device&);
+    static NonnullRefPtr<SysFSUSBDeviceInformation> create(USB::Device&);
 
     RefPtr<USB::Device> device() const { return m_device; }
 
 protected:
-    explicit ProcFSUSBDeviceInformation(USB::Device& device)
+    explicit SysFSUSBDeviceInformation(USB::Device& device)
-        : ProcFSGlobalInformation(String::formatted("{}", device.address()))
+        : SysFSComponent(String::number(device.address()))
         , m_device(device)
     {
     }
-    virtual bool output(KBufferBuilder& builder) override
-    {
-        VERIFY(m_device); // Something has gone very wrong if this isn't true
 
+    virtual KResultOr<size_t> read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, FileDescription*) const override
+    {
+        KBufferBuilder builder;
         JsonArraySerializer array { builder };
 
         auto obj = array.add_object();
@@ -109,14 +109,24 @@ protected:
         obj.add("num_configurations", m_device->device_descriptor().num_configurations);
         obj.finish();
         array.finish();
-        return true;
+
+        auto data = builder.build();
+        if (!data)
+            return ENOMEM;
+
+        ssize_t nread = min(static_cast<off_t>(data->size() - offset), static_cast<off_t>(count));
+        if (!buffer.write(data->data() + offset, nread))
+            return EFAULT;
+
+        return nread;
     }
-    IntrusiveListNode<ProcFSUSBDeviceInformation, RefPtr<ProcFSUSBDeviceInformation>> m_list_node;
+    IntrusiveListNode<SysFSUSBDeviceInformation, RefPtr<SysFSUSBDeviceInformation>> m_list_node;
-    RefPtr<USB::Device> m_device;
+
+    NonnullRefPtr<USB::Device> m_device;
 };
 
-class ProcFSUSBBusDirectory final : public ProcFSExposedDirectory {
+class SysFSUSBBusDirectory final : public SysFSDirectory {
-    friend class ProcFSComponentsRegistrar;
+    friend class SysFSComponentsRegistrar;
 
 public:
     static void initialize();
@@ -124,25 +134,24 @@ public:
     void unplug(USB::Device&);
 
     virtual KResult traverse_as_directory(unsigned, Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
-    virtual RefPtr<ProcFSExposedComponent> lookup(StringView name) override;
+    virtual RefPtr<SysFSComponent> lookup(StringView name) override;
 
 private:
-    ProcFSUSBBusDirectory(const ProcFSBusDirectory&);
+    explicit SysFSUSBBusDirectory(SysFSBusDirectory&);
 
-    RefPtr<ProcFSUSBDeviceInformation> device_node_for(USB::Device& device);
+    RefPtr<SysFSUSBDeviceInformation> device_node_for(USB::Device& device);
 
-    IntrusiveList<ProcFSUSBDeviceInformation, RefPtr<ProcFSUSBDeviceInformation>, &ProcFSUSBDeviceInformation::m_list_node> m_device_nodes;
+    IntrusiveList<SysFSUSBDeviceInformation, RefPtr<SysFSUSBDeviceInformation>, &SysFSUSBDeviceInformation::m_list_node> m_device_nodes;
     mutable SpinLock<u8> m_lock;
 };
 
-KResult ProcFSUSBBusDirectory::traverse_as_directory(unsigned fsid, Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
+KResult SysFSUSBBusDirectory::traverse_as_directory(unsigned fsid, Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
 {
     ScopedSpinLock lock(m_lock);
-    auto parent_directory = m_parent_directory.strong_ref();
     // Note: if the parent directory is null, it means something bad happened as this should not happen for the USB directory.
-    VERIFY(parent_directory);
+    VERIFY(m_parent_directory);
     callback({ ".", { fsid, component_index() }, 0 });
-    callback({ "..", { fsid, parent_directory->component_index() }, 0 });
+    callback({ "..", { fsid, m_parent_directory->component_index() }, 0 });
 
     for (auto& device_node : m_device_nodes) {
         InodeIdentifier identifier = { fsid, device_node.component_index() };
@@ -150,7 +159,7 @@ KResult ProcFSUSBBusDirectory::traverse_as_directory(unsigned fsid, Function<boo
     }
     return KSuccess;
 }
-RefPtr<ProcFSExposedComponent> ProcFSUSBBusDirectory::lookup(StringView name)
+RefPtr<SysFSComponent> SysFSUSBBusDirectory::lookup(StringView name)
 {
     ScopedSpinLock lock(m_lock);
     for (auto& device_node : m_device_nodes) {
@@ -161,7 +170,7 @@ RefPtr<ProcFSExposedComponent> ProcFSUSBBusDirectory::lookup(StringView name)
     return {};
 }
 
-RefPtr<ProcFSUSBDeviceInformation> ProcFSUSBBusDirectory::device_node_for(USB::Device& device)
+RefPtr<SysFSUSBDeviceInformation> SysFSUSBBusDirectory::device_node_for(USB::Device& device)
 {
     RefPtr<USB::Device> checked_device = device;
     for (auto& device_node : m_device_nodes) {
@@ -171,14 +180,15 @@ RefPtr<ProcFSUSBDeviceInformation> ProcFSUSBBusDirectory::device_node_for(USB::D
     return {};
 }
 
-void ProcFSUSBBusDirectory::plug(USB::Device& new_device)
+void SysFSUSBBusDirectory::plug(USB::Device& new_device)
 {
     ScopedSpinLock lock(m_lock);
     auto device_node = device_node_for(new_device);
     VERIFY(!device_node);
-    m_device_nodes.append(ProcFSUSBDeviceInformation::create(new_device));
+    m_device_nodes.append(SysFSUSBDeviceInformation::create(new_device));
 }
-void ProcFSUSBBusDirectory::unplug(USB::Device& deleted_device)
+
+void SysFSUSBBusDirectory::unplug(USB::Device& deleted_device)
 {
     ScopedSpinLock lock(m_lock);
     auto device_node = device_node_for(deleted_device);
@@ -186,21 +196,21 @@ void ProcFSUSBBusDirectory::unplug(USB::Device& deleted_device)
     device_node->m_list_node.remove();
 }
 
-UNMAP_AFTER_INIT ProcFSUSBBusDirectory::ProcFSUSBBusDirectory(const ProcFSBusDirectory& buses_directory)
+UNMAP_AFTER_INIT SysFSUSBBusDirectory::SysFSUSBBusDirectory(SysFSBusDirectory& buses_directory)
-    : ProcFSExposedDirectory("usb"sv, buses_directory)
+    : SysFSDirectory("usb"sv, buses_directory)
 {
 }
 
-UNMAP_AFTER_INIT void ProcFSUSBBusDirectory::initialize()
+UNMAP_AFTER_INIT void SysFSUSBBusDirectory::initialize()
 {
-    auto directory = adopt_ref(*new ProcFSUSBBusDirectory(ProcFSComponentRegistry::the().buses_directory()));
+    auto directory = adopt_ref(*new SysFSUSBBusDirectory(SysFSComponentRegistry::the().buses_directory()));
-    ProcFSComponentRegistry::the().register_new_bus_directory(directory);
+    SysFSComponentRegistry::the().register_new_bus_directory(directory);
     s_procfs_usb_bus_directory = directory;
 }
 
-NonnullRefPtr<ProcFSUSBDeviceInformation> ProcFSUSBDeviceInformation::create(USB::Device& device)
+NonnullRefPtr<SysFSUSBDeviceInformation> SysFSUSBDeviceInformation::create(USB::Device& device)
 {
-    return adopt_ref(*new ProcFSUSBDeviceInformation(device));
+    return adopt_ref(*new SysFSUSBDeviceInformation(device));
 }
 
 UHCIController& UHCIController::the()
@@ -215,7 +225,7 @@ UNMAP_AFTER_INIT void UHCIController::detect()
 
     // FIXME: We create the /proc/bus/usb representation here, but it should really be handled
     // in a more broad singleton than this once we refactor things in USB subsystem.
-    ProcFSUSBBusDirectory::initialize();
+    SysFSUSBBusDirectory::initialize();
 
     PCI::enumerate([&](const PCI::Address& address, PCI::ID id) {
         if (address.is_null())

Kernel/FileSystem/ProcFS.cpp

@@ -36,17 +36,6 @@ UNMAP_AFTER_INIT ProcFSComponentRegistry::ProcFSComponentRegistry()
 {
 }
 
-const ProcFSBusDirectory& ProcFSComponentRegistry::buses_directory() const
-{
-    return *m_root_directory->m_buses_directory;
-}
-
-void ProcFSComponentRegistry::register_new_bus_directory(ProcFSExposedDirectory& new_bus_directory)
-{
-    VERIFY(!m_root_directory->m_buses_directory.is_null());
-    m_root_directory->m_buses_directory->m_components.append(new_bus_directory);
-}
-
 void ProcFSComponentRegistry::register_new_process(Process& new_process)
 {
     Locker locker(m_lock);

Kernel/FileSystem/SysFS.cpp

@@ -56,6 +56,9 @@ KResult SysFSRootDirectory::traverse_as_directory(unsigned fsid, Function<bool(F
 SysFSRootDirectory::SysFSRootDirectory()
     : SysFSDirectory(".")
 {
+    auto buses_directory = SysFSBusDirectory::must_create(*this);
+    m_components.append(buses_directory);
+    m_buses_directory = buses_directory;
 }
 
 NonnullRefPtr<SysFS> SysFS::create()
@@ -174,6 +177,7 @@ SysFSDirectoryInode::SysFSDirectoryInode(SysFS const& fs, SysFSComponent const&
 SysFSDirectoryInode::~SysFSDirectoryInode()
 {
 }
+
 InodeMetadata SysFSDirectoryInode::metadata() const
 {
     Locker locker(m_inode_lock);
@@ -201,4 +205,26 @@ RefPtr<Inode> SysFSDirectoryInode::lookup(StringView name)
     return component->to_inode(m_parent_fs);
 }
 
+SysFSBusDirectory& SysFSComponentRegistry::buses_directory()
+{
+    return *m_root_directory->m_buses_directory;
+}
+
+void SysFSComponentRegistry::register_new_bus_directory(SysFSDirectory& new_bus_directory)
+{
+    VERIFY(!m_root_directory->m_buses_directory.is_null());
+    m_root_directory->m_buses_directory->m_components.append(new_bus_directory);
+}
+
+UNMAP_AFTER_INIT NonnullRefPtr<SysFSBusDirectory> SysFSBusDirectory::must_create(SysFSRootDirectory const& parent_directory)
+{
+    auto directory = adopt_ref(*new (nothrow) SysFSBusDirectory(parent_directory));
+    return directory;
+}
+
+UNMAP_AFTER_INIT SysFSBusDirectory::SysFSBusDirectory(SysFSRootDirectory const& parent_directory)
+    : SysFSDirectory("bus"sv, parent_directory)
+{
+}
+
 }

Kernel/FileSystem/SysFS.h

@@ -21,6 +21,17 @@ public:
 
 private:
     SysFSRootDirectory();
+    RefPtr<SysFSBusDirectory> m_buses_directory;
+};
+
+class SysFSBusDirectory : public SysFSDirectory {
+    friend class SysFSComponentRegistry;
+
+public:
+    static NonnullRefPtr<SysFSBusDirectory> must_create(SysFSRootDirectory const&);
+
+private:
+    explicit SysFSBusDirectory(SysFSRootDirectory const&);
 };
 
 class SysFSComponentRegistry {
@@ -35,6 +46,9 @@ public:
     SysFSDirectory& root_directory() { return m_root_directory; }
     Mutex& get_lock() { return m_lock; }
 
+    void register_new_bus_directory(SysFSDirectory&);
+    SysFSBusDirectory& buses_directory();
+
 private:
     Mutex m_lock;
     NonnullRefPtr<SysFSRootDirectory> m_root_directory;

Kernel/Forward.h

@@ -40,7 +40,6 @@ class PerformanceEventBuffer;
 class PhysicalPage;
 class PhysicalRegion;
 class ProcFS;
-class ProcFSBusDirectory;
 class ProcFSDirectoryInode;
 class ProcFSExposedComponent;
 class ProcFSExposedDirectory;
@@ -61,6 +60,8 @@ class SharedInodeVMObject;
 class Socket;
 class Space;
 class SysFS;
+class SysFSDirectory;
+class SysFSBusDirectory;
 class SysFSDirectoryInode;
 class SysFSInode;
 class TCPSocket;

Kernel/GlobalProcessExposed.cpp

@@ -813,12 +813,6 @@ UNMAP_AFTER_INIT ProcFSProfile::ProcFSProfile()
 {
 }
 
-UNMAP_AFTER_INIT NonnullRefPtr<ProcFSBusDirectory> ProcFSBusDirectory::must_create(const ProcFSRootDirectory& parent_directory)
-{
-    auto directory = adopt_ref(*new (nothrow) ProcFSBusDirectory(parent_directory));
-    return directory;
-}
-
 UNMAP_AFTER_INIT NonnullRefPtr<ProcFSSystemDirectory> ProcFSSystemDirectory::must_create(const ProcFSRootDirectory& parent_directory)
 {
     auto directory = adopt_ref(*new (nothrow) ProcFSSystemDirectory(parent_directory));
@@ -828,10 +822,6 @@ UNMAP_AFTER_INIT NonnullRefPtr<ProcFSSystemDirectory> ProcFSSystemDirectory::mus
     return directory;
 }
 
-UNMAP_AFTER_INIT ProcFSBusDirectory::ProcFSBusDirectory(const ProcFSRootDirectory& parent_directory)
-    : ProcFSExposedDirectory("bus"sv, parent_directory)
-{
-}
 UNMAP_AFTER_INIT ProcFSSystemDirectory::ProcFSSystemDirectory(const ProcFSRootDirectory& parent_directory)
     : ProcFSExposedDirectory("sys"sv, parent_directory)
 {
@@ -856,9 +846,6 @@ UNMAP_AFTER_INIT NonnullRefPtr<ProcFSRootDirectory> ProcFSRootDirectory::must_cr
     directory->m_components.append(ProcFSProfile::must_create());
 
     directory->m_components.append(ProcFSNetworkDirectory::must_create(*directory));
-    auto buses_directory = ProcFSBusDirectory::must_create(*directory);
-    directory->m_components.append(buses_directory);
-    directory->m_buses_directory = buses_directory;
     directory->m_components.append(ProcFSSystemDirectory::must_create(*directory));
     return directory;
 }

Kernel/ProcessExposed.h

@@ -30,9 +30,6 @@ public:
     InodeIndex allocate_inode_index() const;
 
     ProcFSComponentRegistry();
-    void register_new_bus_directory(ProcFSExposedDirectory&);
-
-    const ProcFSBusDirectory& buses_directory() const;
 
     void register_new_process(Process&);
     void unregister_process(Process&);
@@ -157,16 +154,6 @@ private:
     RefPtr<Process> m_associated_process;
 };
 
-class ProcFSBusDirectory : public ProcFSExposedDirectory {
-    friend class ProcFSComponentRegistry;
-
-public:
-    static NonnullRefPtr<ProcFSBusDirectory> must_create(const ProcFSRootDirectory& parent_directory);
-
-private:
-    ProcFSBusDirectory(const ProcFSRootDirectory& parent_directory);
-};
-
 class ProcFSRootDirectory final : public ProcFSExposedDirectory {
     friend class ProcFSComponentRegistry;
 
@@ -181,7 +168,6 @@ private:
     virtual KResult traverse_as_directory(unsigned, Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
     ProcFSRootDirectory();
 
-    RefPtr<ProcFSBusDirectory> m_buses_directory;
     IntrusiveList<ProcFSProcessDirectory, RefPtr<ProcFSProcessDirectory>, &ProcFSProcessDirectory::m_list_node> m_process_directories;
 };
 

Userland/Utilities/lsusb.cpp

@@ -23,7 +23,7 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    if (unveil("/proc/bus/usb", "r") < 0) {
+    if (unveil("/sys/bus/usb", "r") < 0) {
         perror("unveil");
         return 1;
     }
@@ -42,7 +42,7 @@ int main(int argc, char** argv)
     args.set_general_help("List USB devices.");
     args.parse(argc, argv);
 
-    Core::DirIterator usb_devices("/proc/bus/usb", Core::DirIterator::SkipDots);
+    Core::DirIterator usb_devices("/sys/bus/usb", Core::DirIterator::SkipDots);
 
     RefPtr<USBDB::Database> usb_db = USBDB::Database::open();
     if (!usb_db) {