Kernel: Have TTY subclasses cache their tty_name/pts_name.

Kernel/TTY/MasterPTY.cpp

@@ -13,6 +13,7 @@ MasterPTY::MasterPTY(unsigned index)
     , m_slave(adopt(*new SlavePTY(*this, index)))
     , m_index(index)
 {
+    m_pts_name = String::format("/dev/pts/%u", m_index);
     set_uid(current->process().uid());
     set_gid(current->process().gid());
 }
@@ -27,7 +28,7 @@ MasterPTY::~MasterPTY()
 
 String MasterPTY::pts_name() const
 {
-    return String::format("/dev/pts/%u", m_index);
+    return m_pts_name;
 }
 
 ssize_t MasterPTY::read(Process&, byte* buffer, ssize_t size)

Kernel/TTY/MasterPTY.h

@@ -33,4 +33,5 @@ private:
     unsigned m_index;
     bool m_closed { false };
     DoubleBuffer m_buffer;
+    String m_pts_name;
 };

Kernel/TTY/SlavePTY.cpp

@@ -10,6 +10,7 @@ SlavePTY::SlavePTY(MasterPTY& master, unsigned index)
     , m_master(master)
     , m_index(index)
 {
+    m_tty_name = String::format("/dev/pts/%u", m_index);
     set_uid(current->process().uid());
     set_gid(current->process().gid());
     DevPtsFS::the().register_slave_pty(*this);
@@ -26,7 +27,7 @@ SlavePTY::~SlavePTY()
 
 String SlavePTY::tty_name() const
 {
-    return String::format("/dev/pts/%u", m_index);
+    return m_tty_name;
 }
 
 void SlavePTY::on_master_write(const byte* buffer, ssize_t size)

Kernel/TTY/SlavePTY.h

@@ -32,5 +32,6 @@ private:
     RetainPtr<MasterPTY> m_master;
     unsigned m_index;
     InodeIdentifier m_devpts_inode_id;
+    String m_tty_name;
 };
 

Kernel/TTY/VirtualConsole.cpp

@@ -40,6 +40,7 @@ VirtualConsole::VirtualConsole(unsigned index, InitialContents initial_contents)
     : TTY(4, index)
     , m_index(index)
 {
+    m_tty_name = String::format("/dev/tty%u", m_index);
     set_size(80, 25);
     m_horizontal_tabs = static_cast<byte*>(kmalloc(columns()));
     for (unsigned i = 0; i < columns(); ++i)
@@ -508,7 +509,7 @@ ssize_t VirtualConsole::on_tty_write(const byte* data, ssize_t size)
 
 String VirtualConsole::tty_name() const
 {
-    return String::format("/dev/tty%u", m_index);
+    return m_tty_name;
 }
 
 void VirtualConsole::set_vga_start_row(word row)

Kernel/TTY/VirtualConsole.h

@@ -78,4 +78,5 @@ private:
     Vector<byte> m_parameters;
     Vector<byte> m_intermediates;
     byte* m_horizontal_tabs { nullptr };
+    String m_tty_name;
 };