Add some simple write buffering to LibC's stdio.

Plumb it all the way to the VirtualConsole. Also fix /bin/cat to write()
the whole chunks we get from read() directly to stdout.

Kernel/Process.cpp

@@ -29,15 +29,19 @@
 #define VALIDATE_USER_READ(b, s) \
     do { \
         LinearAddress laddr((dword)(b)); \
-        if (!validate_user_read(laddr) || !validate_user_read(laddr.offset((s) - 1))) \
+        if (!validate_user_read(laddr) || !validate_user_read(laddr.offset((s) - 1))) { \
+            dbgprintf("Bad read address passed to syscall: %p +%u\n", laddr.get(), (s)); \
             return -EFAULT; \
+        } \
     } while(0)
 
 #define VALIDATE_USER_WRITE(b, s) \
     do { \
         LinearAddress laddr((dword)(b)); \
-        if (!validate_user_write(laddr) || !validate_user_write(laddr.offset((s) - 1))) \
+        if (!validate_user_write(laddr) || !validate_user_write(laddr.offset((s) - 1))) { \
+            dbgprintf("Bad write address passed to syscall: %p +%u\n", laddr.get(), (s)); \
             return -EFAULT; \
+        } \
     } while(0)
 
 static const DWORD defaultStackSize = 16384;

Kernel/TTY.cpp

@@ -26,8 +26,7 @@ ssize_t TTY::read(byte* buffer, size_t size)
 
 ssize_t TTY::write(const byte* buffer, size_t size)
 {
-    for (size_t i = 0; i < size; ++i)
-        onTTYWrite(buffer[i]);
+    onTTYWrite(buffer, size);
     return 0;
 }
 

Kernel/TTY.h

@@ -21,7 +21,7 @@ protected:
     TTY(unsigned major, unsigned minor);
     void emit(byte);
 
-    virtual void onTTYWrite(byte) = 0;
+    virtual void onTTYWrite(const byte*, size_t) = 0;
 
     void interrupt();
 

Kernel/VirtualConsole.cpp

@@ -320,7 +320,6 @@ void VirtualConsole::put_character_at(unsigned row, unsigned column, byte ch)
 
 void VirtualConsole::on_char(byte ch, bool shouldEmit)
 {
-    InterruptDisabler disabler;
     if (shouldEmit)
         emit(ch);
 
@@ -397,15 +396,18 @@ void VirtualConsole::onKeyPress(Keyboard::Key key)
 
 void VirtualConsole::onConsoleReceive(byte ch)
 {
+    InterruptDisabler disabler;
     auto old_attribute = m_current_attribute;
     m_current_attribute = 0x03;
     on_char(ch, false);
     m_current_attribute = old_attribute;
 }
 
-void VirtualConsole::onTTYWrite(byte ch)
+void VirtualConsole::onTTYWrite(const byte* data, size_t size)
 {
-    on_char(ch, false);
+    InterruptDisabler disabler;
+    for (size_t i = 0; i < size; ++i)
+        on_char(data[i], false);
 }
 
 String VirtualConsole::ttyName() const

Kernel/VirtualConsole.h

@@ -23,7 +23,7 @@ private:
     virtual void onConsoleReceive(byte) override;
 
     // ^TTY
-    virtual void onTTYWrite(byte) override;
+    virtual void onTTYWrite(const byte*, size_t) override;
     virtual String ttyName() const override;
 
     void set_active(bool);