Kernel: Make /proc/PID/fds display something useful for character devices.

14 files changed, 44 insertions, 4 deletions

diff --git a/Kernel/Console.h b/Kernel/Console.h
index fe4c3aea70..962ff09aab 100644
--- a/Kernel/Console.h
+++ b/Kernel/Console.h
@@ -18,10 +18,12 @@ public:
     Console();
     virtual ~Console() override;
 
+    // ^CharacterDevice
     virtual bool can_read(Process&) const override;
     virtual bool can_write(Process&) const override { return true; }
     virtual ssize_t read(Process&, byte* buffer, size_t size) override;
     virtual ssize_t write(Process&, const byte* data, size_t size) override;
+    virtual const char* class_name() const override { return "Console"; }
 
     void setImplementation(ConsoleImplementation* implementation) { m_implementation = implementation; }
 
diff --git a/Kernel/GUIEventDevice.h b/Kernel/GUIEventDevice.h
index e98b208f05..6fe7dfd314 100644
--- a/Kernel/GUIEventDevice.h
+++ b/Kernel/GUIEventDevice.h
@@ -13,4 +13,5 @@ private:
     virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) override;
     virtual bool can_read(Process&) const override;
     virtual bool can_write(Process&) const override { return true; }
+    virtual const char* class_name() const override { return "GUIEventDevice"; }
 };
diff --git a/Kernel/Keyboard.h b/Kernel/Keyboard.h
index e7debc403b..924a3a3a06 100644
--- a/Kernel/Keyboard.h
+++ b/Kernel/Keyboard.h
@@ -42,6 +42,9 @@ private:
     // ^IRQHandler
     virtual void handle_irq() override;
 
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "Keyboard"; }
+
     void emit(byte);
 
     KeyboardClient* m_client { nullptr };
diff --git a/Kernel/MasterPTY.h b/Kernel/MasterPTY.h
index aa4a27daf0..7c85dfea56 100644
--- a/Kernel/MasterPTY.h
+++ b/Kernel/MasterPTY.h
@@ -10,6 +10,7 @@ public:
     explicit MasterPTY(unsigned index);
     virtual ~MasterPTY() override;
 
+    // ^CharacterDevice
     virtual ssize_t read(Process&, byte*, size_t) override;
     virtual ssize_t write(Process&, const byte*, size_t) override;
     virtual bool can_read(Process&) const override;
@@ -21,6 +22,9 @@ public:
     void on_slave_write(const byte*, size_t);
 
 private:
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "MasterPTY"; }
+
     SlavePTY& m_slave;
     unsigned m_index;
     DoubleBuffer m_buffer;
diff --git a/Kernel/PS2MouseDevice.h b/Kernel/PS2MouseDevice.h
index cb68b3f3e2..a06975c047 100644
--- a/Kernel/PS2MouseDevice.h
+++ b/Kernel/PS2MouseDevice.h
@@ -20,6 +20,9 @@ private:
     // ^IRQHandler
     virtual void handle_irq() override;
 
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "PS2MouseDevice"; }
+
     void initialize();
     void prepare_for_input();
     void prepare_for_output();
diff --git a/Kernel/PTYMultiplexer.h b/Kernel/PTYMultiplexer.h
index fe91f6eb34..bd1afe6a66 100644
--- a/Kernel/PTYMultiplexer.h
+++ b/Kernel/PTYMultiplexer.h
@@ -19,6 +19,9 @@ public:
     virtual bool can_write(Process&) const override { return true; }
 
 private:
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "PTYMultiplexer"; }
+
     Lock m_lock;
     Vector<RetainPtr<MasterPTY>> m_freelist;
 };
diff --git a/Kernel/SlavePTY.h b/Kernel/SlavePTY.h
index 1b01219349..23aa996840 100644
--- a/Kernel/SlavePTY.h
+++ b/Kernel/SlavePTY.h
@@ -8,16 +8,18 @@ class SlavePTY final : public TTY {
 public:
     virtual ~SlavePTY() override;
 
-    virtual String tty_name() const override;
-
     void on_master_write(const byte*, size_t);
     unsigned index() const { return m_index; }
 
-protected:
+private:
+    // ^TTY
+    virtual String tty_name() const override;
     virtual void on_tty_write(const byte*, size_t) override;
+
+    // ^CharacterDevice
     virtual bool can_write(Process&) const override;
+    virtual const char* class_name() const override { return "SlavePTY"; }
 
-private:
     friend class MasterPTY;
     SlavePTY(MasterPTY&, unsigned index);
 
diff --git a/Kernel/VirtualConsole.h b/Kernel/VirtualConsole.h
index 2888ced10d..3b688174d7 100644
--- a/Kernel/VirtualConsole.h
+++ b/Kernel/VirtualConsole.h
@@ -26,6 +26,9 @@ private:
     virtual void on_tty_write(const byte*, size_t) override;
     virtual String tty_name() const override;
 
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "VirtualConsole"; }
+
     void set_active(bool);
     void on_char(byte);
 
diff --git a/VirtualFileSystem/CharacterDevice.h b/VirtualFileSystem/CharacterDevice.h
index 92c29ed2cd..c37cbf0600 100644
--- a/VirtualFileSystem/CharacterDevice.h
+++ b/VirtualFileSystem/CharacterDevice.h
@@ -29,6 +29,8 @@ public:
 
     virtual int ioctl(Process&, unsigned request, unsigned arg);
 
+    virtual const char* class_name() const = 0;
+
 protected:
     CharacterDevice(unsigned major, unsigned minor) : m_major(major), m_minor(minor) { }
 
diff --git a/VirtualFileSystem/FileDescriptor.cpp b/VirtualFileSystem/FileDescriptor.cpp
index 6b20ee8ef9..15d2a79b68 100644
--- a/VirtualFileSystem/FileDescriptor.cpp
+++ b/VirtualFileSystem/FileDescriptor.cpp
@@ -297,6 +297,11 @@ String FileDescriptor::absolute_path()
         ksprintf(buf, "fifo:%x", m_fifo.ptr());
         return buf;
     }
+    if (is_character_device()) {
+        char buf[128];
+        ksprintf(buf, "device:%u,%u (%s)", m_device->major(), m_device->minor(), m_device->class_name());
+        return buf;
+    }
     ASSERT(m_inode);
     return VFS::the().absolute_path(*m_inode);
 }
diff --git a/VirtualFileSystem/FullDevice.h b/VirtualFileSystem/FullDevice.h
index 44b6af0a8c..a900ac2536 100644
--- a/VirtualFileSystem/FullDevice.h
+++ b/VirtualFileSystem/FullDevice.h
@@ -8,9 +8,12 @@ public:
     FullDevice();
     virtual ~FullDevice() override;
 
+private:
+    // ^CharacterDevice
     virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) override;
     virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) override;
     virtual bool can_read(Process&) const override;
     virtual bool can_write(Process&) const override { return true; }
+    virtual const char* class_name() const override { return "FullDevice"; }
 };
 
diff --git a/VirtualFileSystem/NullDevice.h b/VirtualFileSystem/NullDevice.h
index 9e51f1da5c..22c3637bb0 100644
--- a/VirtualFileSystem/NullDevice.h
+++ b/VirtualFileSystem/NullDevice.h
@@ -8,9 +8,12 @@ public:
     NullDevice();
     virtual ~NullDevice() override;
 
+private:
+    // ^CharacterDevice
     virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) override;
     virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) override;
     virtual bool can_write(Process&) const override { return true; }
     virtual bool can_read(Process&) const override;
+    virtual const char* class_name() const override { return "CharacterDevice"; }
 };
 
diff --git a/VirtualFileSystem/RandomDevice.h b/VirtualFileSystem/RandomDevice.h
index 4711542a54..defaebff9d 100644
--- a/VirtualFileSystem/RandomDevice.h
+++ b/VirtualFileSystem/RandomDevice.h
@@ -8,9 +8,12 @@ public:
     RandomDevice();
     virtual ~RandomDevice() override;
 
+private:
+    // ^CharacterDevice
     virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) override;
     virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) override;
     virtual bool can_read(Process&) const override;
     virtual bool can_write(Process&) const override { return true; }
+    virtual const char* class_name() const override { return "RandomDevice"; }
 };
 
diff --git a/VirtualFileSystem/ZeroDevice.h b/VirtualFileSystem/ZeroDevice.h
index d3440781a0..ee7f2dde37 100644
--- a/VirtualFileSystem/ZeroDevice.h
+++ b/VirtualFileSystem/ZeroDevice.h
@@ -8,9 +8,12 @@ public:
     ZeroDevice();
     virtual ~ZeroDevice() override;
 
+private:
+    // ^CharacterDevice
     virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) override;
     virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) override;
     virtual bool can_read(Process&) const override;
     virtual bool can_write(Process&) const override { return true; }
+    virtual const char* class_name() const override { return "ZeroDevice"; }
 };