Kernel+LibC: Turn errno codes into a strongly typed enum

..and allow implicit creation of KResult and KResultOr from ErrnoCode.
This means that kernel functions that return those types can finally
do "return EINVAL;" and it will just work.

There's a handful of functions that still deal with signed integers
that should be converted to return KResults.

3 files changed, 5 insertions, 5 deletions

diff --git a/Kernel/TTY/MasterPTY.cpp b/Kernel/TTY/MasterPTY.cpp
index eca9f4c2fa..538b471699 100644
--- a/Kernel/TTY/MasterPTY.cpp
+++ b/Kernel/TTY/MasterPTY.cpp
@@ -75,7 +75,7 @@ KResultOr<size_t> MasterPTY::read(FileDescription&, size_t, UserOrKernelBuffer&
 KResultOr<size_t> MasterPTY::write(FileDescription&, size_t, const UserOrKernelBuffer& buffer, size_t size)
 {
     if (!m_slave)
-        return KResult(-EIO);
+        return EIO;
     m_slave->on_master_write(buffer, size);
     return size;
 }
diff --git a/Kernel/TTY/PTYMultiplexer.cpp b/Kernel/TTY/PTYMultiplexer.cpp
index 7a9789c544..3ccf768b6d 100644
--- a/Kernel/TTY/PTYMultiplexer.cpp
+++ b/Kernel/TTY/PTYMultiplexer.cpp
@@ -59,7 +59,7 @@ KResultOr<NonnullRefPtr<FileDescription>> PTYMultiplexer::open(int options)
 {
     LOCKER(m_lock);
     if (m_freelist.is_empty())
-        return KResult(-EBUSY);
+        return EBUSY;
     auto master_index = m_freelist.take_last();
     auto master = adopt(*new MasterPTY(master_index));
 #ifdef PTMX_DEBUG
diff --git a/Kernel/TTY/TTY.cpp b/Kernel/TTY/TTY.cpp
index 4375eef40c..bde26f6da7 100644
--- a/Kernel/TTY/TTY.cpp
+++ b/Kernel/TTY/TTY.cpp
@@ -58,7 +58,7 @@ KResultOr<size_t> TTY::read(FileDescription&, size_t, UserOrKernelBuffer& buffer
     if (Process::current()->pgid() != pgid()) {
         // FIXME: Should we propagate this error path somehow?
         [[maybe_unused]] auto rc = Process::current()->send_signal(SIGTTIN, nullptr);
-        return KResult(-EINTR);
+        return EINTR;
     }
 
     if (m_input_buffer.size() < static_cast<size_t>(size))
@@ -95,7 +95,7 @@ KResultOr<size_t> TTY::read(FileDescription&, size_t, UserOrKernelBuffer& buffer
         });
     }
     if (nwritten < 0)
-        return KResult(nwritten);
+        return KResult((ErrnoCode)-nwritten);
     if (nwritten > 0 || need_evaluate_block_conditions)
         evaluate_block_conditions();
     return (size_t)nwritten;
@@ -105,7 +105,7 @@ KResultOr<size_t> TTY::write(FileDescription&, size_t, const UserOrKernelBuffer&
 {
     if (m_termios.c_lflag & TOSTOP && Process::current()->pgid() != pgid()) {
         [[maybe_unused]] auto rc = Process::current()->send_signal(SIGTTOU, nullptr);
-        return KResult(-EINTR);
+        return EINTR;
     }
 
     on_tty_write(buffer, size);