Kernel: Closing a MasterPTY should generate a TTY hangup.

Kernel/MasterPTY.cpp

@@ -3,6 +3,7 @@
 #include "PTYMultiplexer.h"
 #include <Kernel/Process.h>
 #include <LibC/errno_numbers.h>
+#include <LibC/signal_numbers.h>
 
 MasterPTY::MasterPTY(unsigned index)
     : CharacterDevice(10, index)
@@ -73,8 +74,11 @@ bool MasterPTY::can_write_from_slave() const
 void MasterPTY::close()
 {
     if (retain_count() == 2) {
+        InterruptDisabler disabler;
         // After the closing FileDescriptor dies, slave is the only thing keeping me alive.
         // From this point, let's consider ourselves closed.
         m_closed = true;
+
+        m_slave->hang_up();
     }
 }

Kernel/Process.h

@@ -87,7 +87,7 @@ public:
 
     bool is_blocked() const
     {
-        return m_state == BlockedSleep || m_state == BlockedWait || m_state == BlockedRead || m_state == BlockedSignal || m_state == BlockedSelect;
+        return m_state == BlockedSleep || m_state == BlockedWait || m_state == BlockedRead || m_state == BlockedWrite || m_state == BlockedSignal || m_state == BlockedSelect;
     }
 
     PageDirectory& page_directory() { return *m_page_directory; }

Kernel/TTY.cpp

@@ -161,3 +161,8 @@ void TTY::set_size(unsigned short columns, unsigned short rows)
     m_rows = rows;
     m_columns = columns;
 }
+
+void TTY::hang_up()
+{
+    generate_signal(SIGHUP);
+}

Kernel/TTY.h

@@ -30,6 +30,7 @@ public:
     bool in_canonical_mode() const { return m_termios.c_lflag & ICANON; }
 
     void set_default_termios();
+    void hang_up();
 
 protected:
     virtual void on_tty_write(const byte*, size_t) = 0;
@@ -38,12 +39,12 @@ protected:
     TTY(unsigned major, unsigned minor);
     void emit(byte);
 
+    void generate_signal(int signal);
+
 private:
     // ^CharacterDevice
     virtual bool is_tty() const final override { return true; }
 
-    void generate_signal(int signal);
-
     DoubleBuffer m_buffer;
     pid_t m_pgid { 0 };
     termios m_termios;