Kernel: Writing to a slave PTY should yield EIO if the master is closed.

Kernel/MasterPTY.cpp

@@ -61,13 +61,18 @@ void MasterPTY::notify_slave_closed(Badge<SlavePTY>)
         m_slave = nullptr;
 }
 
-void MasterPTY::on_slave_write(const byte* data, size_t size)
+ssize_t MasterPTY::on_slave_write(const byte* data, size_t size)
 {
+    if (m_closed)
+        return -EIO;
     m_buffer.write(data, size);
+    return size;
 }
 
 bool MasterPTY::can_write_from_slave() const
 {
+    if (m_closed)
+        return true;
     return m_buffer.bytes_in_write_buffer() < 4096;
 }
 

Kernel/MasterPTY.h

@@ -13,7 +13,7 @@ public:
 
     unsigned index() const { return m_index; }
     String pts_name() const;
-    void on_slave_write(const byte*, size_t);
+    ssize_t on_slave_write(const byte*, size_t);
     bool can_write_from_slave() const;
     void notify_slave_closed(Badge<SlavePTY>);
     bool is_closed() const { return m_closed; }

Kernel/SlavePTY.cpp

@@ -33,9 +33,9 @@ void SlavePTY::on_master_write(const byte* buffer, size_t size)
         emit(buffer[i]);
 }
 
-void SlavePTY::on_tty_write(const byte* data, size_t size)
+ssize_t SlavePTY::on_tty_write(const byte* data, size_t size)
 {
-    m_master->on_slave_write(data, size);
+    return m_master->on_slave_write(data, size);
 }
 
 bool SlavePTY::can_write(Process&) const

Kernel/SlavePTY.h

@@ -17,7 +17,7 @@ public:
 private:
     // ^TTY
     virtual String tty_name() const override;
-    virtual void on_tty_write(const byte*, size_t) override;
+    virtual ssize_t on_tty_write(const byte*, size_t) override;
 
     // ^CharacterDevice
     virtual bool can_read(Process&) const override;

Kernel/TTY.h

@@ -33,7 +33,7 @@ public:
     void hang_up();
 
 protected:
-    virtual void on_tty_write(const byte*, size_t) = 0;
+    virtual ssize_t on_tty_write(const byte*, size_t) = 0;
     void set_size(unsigned short columns, unsigned short rows);
 
     TTY(unsigned major, unsigned minor);

Kernel/VirtualConsole.cpp

@@ -499,11 +499,12 @@ void VirtualConsole::on_sysconsole_receive(byte ch)
     m_current_attribute = old_attribute;
 }
 
-void VirtualConsole::on_tty_write(const byte* data, size_t size)
+ssize_t VirtualConsole::on_tty_write(const byte* data, size_t size)
 {
     InterruptDisabler disabler;
     for (size_t i = 0; i < size; ++i)
         on_char(data[i]);
+    return size;
 }
 
 String VirtualConsole::tty_name() const

Kernel/VirtualConsole.h

@@ -23,7 +23,7 @@ private:
     virtual void on_sysconsole_receive(byte) override;
 
     // ^TTY
-    virtual void on_tty_write(const byte*, size_t) override;
+    virtual ssize_t on_tty_write(const byte*, size_t) override;
     virtual String tty_name() const override;
 
     // ^CharacterDevice