Kernel: Make File::write() and File::read() return KResultOr<size_t>

Instead of returning a ssize_t where negative values mean error, we now return KResultOr<size_t> and use the error state to report errors exclusively.
lanmonster · Aug 4, 2020 · 7a3ab6c · 7a3ab6c
1 parent 58feebe
commit 7a3ab6c
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Showing 58 changed files with 223 additions and 229 deletions.
diff --git a/Kernel/Console.cpp b/Kernel/Console.cpp
@@ -61,18 +61,18 @@ bool Console::can_read(const Kernel::FileDescription&, size_t) const
  return false;
 }
 
-ssize_t Console::read(Kernel::FileDescription&, size_t, u8*, ssize_t)
+Kernel::KResultOr<size_t> Console::read(Kernel::FileDescription&, size_t, u8*, size_t)
 {
  // FIXME: Implement reading from the console.
  // Maybe we could use a ring buffer for this device?
  return 0;
 }
 
-ssize_t Console::write(Kernel::FileDescription&, size_t, const u8* data, ssize_t size)
+Kernel::KResultOr<size_t> Console::write(Kernel::FileDescription&, size_t, const u8* data, size_t size)
 {
  if (!size)
  return 0;
- for (ssize_t i = 0; i < size; ++i)
+ for (size_t i = 0; i < size; ++i)
  put_char(data[i]);
  return size;
 }

diff --git a/Kernel/Console.h b/Kernel/Console.h
@@ -42,8 +42,8 @@ class Console final : public Kernel::CharacterDevice {
  // ^CharacterDevice
  virtual bool can_read(const Kernel::FileDescription&, size_t) const override;
  virtual bool can_write(const Kernel::FileDescription&, size_t) const override { return true; }
- virtual ssize_t read(Kernel::FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(Kernel::FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual Kernel::KResultOr<size_t> read(Kernel::FileDescription&, size_t, u8*, size_t) override;
+ virtual Kernel::KResultOr<size_t> write(Kernel::FileDescription&, size_t, const u8*, size_t) override;
  virtual const char* class_name() const override { return "Console"; }
 
  void put_char(char);

diff --git a/Kernel/Devices/BXVGADevice.h b/Kernel/Devices/BXVGADevice.h
@@ -47,8 +47,8 @@ class BXVGADevice final : public BlockDevice {
  virtual const char* class_name() const override { return "BXVGA"; }
  virtual bool can_read(const FileDescription&, size_t) const override { return true; }
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override { return -EINVAL; }
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override { return -EINVAL; }
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override { return -EINVAL; }
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override { return -EINVAL; }
  virtual bool read_blocks(unsigned, u16, u8*) override { return false; }
  virtual bool write_blocks(unsigned, u16, const u8*) override { return false; }
 

diff --git a/Kernel/Devices/DiskPartition.cpp b/Kernel/Devices/DiskPartition.cpp
@@ -48,7 +48,7 @@ DiskPartition::~DiskPartition()
 {
 }
 
-ssize_t DiskPartition::read(FileDescription& fd, size_t offset, u8* outbuf, ssize_t len)
+KResultOr<size_t> DiskPartition::read(FileDescription& fd, size_t offset, u8* outbuf, size_t len)
 {
  unsigned adjust = m_block_offset * block_size();
 
@@ -70,7 +70,7 @@ bool DiskPartition::can_read(const FileDescription& fd, size_t offset) const
  return m_device->can_read(fd, offset + adjust);
 }
 
-ssize_t DiskPartition::write(FileDescription& fd, size_t offset, const u8* inbuf, ssize_t len)
+KResultOr<size_t> DiskPartition::write(FileDescription& fd, size_t offset, const u8* inbuf, size_t len)
 {
  unsigned adjust = m_block_offset * block_size();
 

diff --git a/Kernel/Devices/DiskPartition.h b/Kernel/Devices/DiskPartition.h
@@ -40,9 +40,9 @@ class DiskPartition final : public BlockDevice {
  virtual bool write_blocks(unsigned index, u16 count, const u8*) override;
 
  // ^BlockDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override;
 
 private:

diff --git a/Kernel/Devices/FullDevice.cpp b/Kernel/Devices/FullDevice.cpp
@@ -46,18 +46,18 @@ bool FullDevice::can_read(const FileDescription&, size_t) const
  return true;
 }
 
-ssize_t FullDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> FullDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
- ssize_t count = min(static_cast<ssize_t>(PAGE_SIZE), size);
- memset(buffer, 0, (size_t)count);
+ ssize_t count = min(static_cast<size_t>(PAGE_SIZE), size);
+ memset(buffer, 0, count);
  return count;
 }
 
-ssize_t FullDevice::write(FileDescription&, size_t, const u8*, ssize_t size)
+KResultOr<size_t> FullDevice::write(FileDescription&, size_t, const u8*, size_t size)
 {
  if (size == 0)
  return 0;
- return -ENOSPC;
+ return KResult(-ENOSPC);
 }
 
 }
diff --git a/Kernel/Devices/FullDevice.h b/Kernel/Devices/FullDevice.h
@@ -38,8 +38,8 @@ class FullDevice final : public CharacterDevice {
 
 private:
  // ^CharacterDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
  virtual const char* class_name() const override { return "FullDevice"; }

diff --git a/Kernel/Devices/KeyboardDevice.cpp b/Kernel/Devices/KeyboardDevice.cpp
@@ -366,9 +366,9 @@ bool KeyboardDevice::can_read(const FileDescription&, size_t) const
  return !m_queue.is_empty();
 }
 
-ssize_t KeyboardDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> KeyboardDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
- ssize_t nread = 0;
+ size_t nread = 0;
  while (nread < size) {
  if (m_queue.is_empty())
  break;
@@ -382,7 +382,7 @@ ssize_t KeyboardDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
  return nread;
 }
 
-ssize_t KeyboardDevice::write(FileDescription&, size_t, const u8*, ssize_t)
+KResultOr<size_t> KeyboardDevice::write(FileDescription&, size_t, const u8*, size_t)
 {
  return 0;
 }

diff --git a/Kernel/Devices/KeyboardDevice.h b/Kernel/Devices/KeyboardDevice.h
@@ -54,9 +54,9 @@ class KeyboardDevice final : public IRQHandler
  void set_maps(Keyboard::CharacterMapData character_map);
 
  // ^CharacterDevice
- virtual ssize_t read(FileDescription&, size_t, u8* buffer, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t write(FileDescription&, size_t, const u8* buffer, ssize_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
 
  virtual const char* purpose() const override { return class_name(); }

diff --git a/Kernel/Devices/MBVGADevice.h b/Kernel/Devices/MBVGADevice.h
@@ -47,8 +47,8 @@ class MBVGADevice final : public BlockDevice {
  virtual const char* class_name() const override { return "MBVGA"; }
  virtual bool can_read(const FileDescription&, size_t) const override { return true; }
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override { return -EINVAL; }
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override { return -EINVAL; }
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override { return -EINVAL; }
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override { return -EINVAL; }
  virtual bool read_blocks(unsigned, u16, u8*) override { return false; }
  virtual bool write_blocks(unsigned, u16, const u8*) override { return false; }
 

diff --git a/Kernel/Devices/NullDevice.cpp b/Kernel/Devices/NullDevice.cpp
@@ -52,14 +52,14 @@ bool NullDevice::can_read(const FileDescription&, size_t) const
  return true;
 }
 
-ssize_t NullDevice::read(FileDescription&, size_t, u8*, ssize_t)
+KResultOr<size_t> NullDevice::read(FileDescription&, size_t, u8*, size_t)
 {
  return 0;
 }
 
-ssize_t NullDevice::write(FileDescription&, size_t, const u8*, ssize_t buffer_size)
+KResultOr<size_t> NullDevice::write(FileDescription&, size_t, const u8*, size_t buffer_size)
 {
- return min(static_cast<ssize_t>(PAGE_SIZE), buffer_size);
+ return min(static_cast<size_t>(PAGE_SIZE), buffer_size);
 }
 
 }
diff --git a/Kernel/Devices/NullDevice.h b/Kernel/Devices/NullDevice.h
@@ -40,8 +40,8 @@ class NullDevice final : public CharacterDevice {
 
 private:
  // ^CharacterDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
  virtual bool can_read(const FileDescription&, size_t) const override;
  virtual const char* class_name() const override { return "NullDevice"; }

diff --git a/Kernel/Devices/PATADiskDevice.cpp b/Kernel/Devices/PATADiskDevice.cpp
@@ -80,7 +80,7 @@ void PATADiskDevice::set_drive_geometry(u16 cyls, u16 heads, u16 spt)
  m_sectors_per_track = spt;
 }
 
-ssize_t PATADiskDevice::read(FileDescription&, size_t offset, u8* outbuf, ssize_t len)
+KResultOr<size_t> PATADiskDevice::read(FileDescription&, size_t offset, u8* outbuf, size_t len)
 {
  unsigned index = offset / block_size();
  u16 whole_blocks = len / block_size();
@@ -121,7 +121,7 @@ bool PATADiskDevice::can_read(const FileDescription&, size_t offset) const
  return offset < (m_cylinders * m_heads * m_sectors_per_track * block_size());
 }
 
-ssize_t PATADiskDevice::write(FileDescription&, size_t offset, const u8* inbuf, ssize_t len)
+KResultOr<size_t> PATADiskDevice::write(FileDescription&, size_t offset, const u8* inbuf, size_t len)
 {
  unsigned index = offset / block_size();
  u16 whole_blocks = len / block_size();

diff --git a/Kernel/Devices/PATADiskDevice.h b/Kernel/Devices/PATADiskDevice.h
@@ -61,9 +61,9 @@ class PATADiskDevice final : public BlockDevice {
  void set_drive_geometry(u16, u16, u16);
 
  // ^BlockDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override;
 
 protected:

diff --git a/Kernel/Devices/PS2MouseDevice.cpp b/Kernel/Devices/PS2MouseDevice.cpp
@@ -324,7 +324,7 @@ bool PS2MouseDevice::can_read(const FileDescription&, size_t) const
  return !m_queue.is_empty();
 }
 
-ssize_t PS2MouseDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> PS2MouseDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
  ASSERT(size > 0);
  size_t nread = 0;
@@ -344,7 +344,7 @@ ssize_t PS2MouseDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
  return nread;
 }
 
-ssize_t PS2MouseDevice::write(FileDescription&, size_t, const u8*, ssize_t)
+KResultOr<size_t> PS2MouseDevice::write(FileDescription&, size_t, const u8*, size_t)
 {
  return 0;
 }

diff --git a/Kernel/Devices/PS2MouseDevice.h b/Kernel/Devices/PS2MouseDevice.h
@@ -44,8 +44,8 @@ class PS2MouseDevice final : public IRQHandler
 
  // ^CharacterDevice
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
 
  virtual const char* purpose() const override { return class_name(); }

diff --git a/Kernel/Devices/RandomDevice.cpp b/Kernel/Devices/RandomDevice.cpp
@@ -43,16 +43,16 @@ bool RandomDevice::can_read(const FileDescription&, size_t) const
  return true;
 }
 
-ssize_t RandomDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> RandomDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
  get_good_random_bytes(buffer, size);
  return size;
 }
 
-ssize_t RandomDevice::write(FileDescription&, size_t, const u8*, ssize_t size)
+KResultOr<size_t> RandomDevice::write(FileDescription&, size_t, const u8*, size_t size)
 {
  // FIXME: Use input for entropy? I guess that could be a neat feature?
- return min(static_cast<ssize_t>(PAGE_SIZE), size);
+ return min(static_cast<size_t>(PAGE_SIZE), size);
 }
 
 }
diff --git a/Kernel/Devices/RandomDevice.h b/Kernel/Devices/RandomDevice.h
@@ -38,8 +38,8 @@ class RandomDevice final : public CharacterDevice {
 
 private:
  // ^CharacterDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
  virtual const char* class_name() const override { return "RandomDevice"; }

diff --git a/Kernel/Devices/SB16.cpp b/Kernel/Devices/SB16.cpp
@@ -172,7 +172,7 @@ bool SB16::can_read(const FileDescription&, size_t) const
  return false;
 }
 
-ssize_t SB16::read(FileDescription&, size_t, u8*, ssize_t)
+KResultOr<size_t> SB16::read(FileDescription&, size_t, u8*, size_t)
 {
  return 0;
 }
@@ -226,7 +226,7 @@ void SB16::wait_for_irq()
  disable_irq();
 }
 
-ssize_t SB16::write(FileDescription&, size_t, const u8* data, ssize_t length)
+KResultOr<size_t> SB16::write(FileDescription&, size_t, const u8* data, size_t length)
 {
  if (!m_dma_region) {
  auto page = MM.allocate_supervisor_physical_page();

diff --git a/Kernel/Devices/SB16.h b/Kernel/Devices/SB16.h
@@ -46,8 +46,8 @@ class SB16 final : public IRQHandler
 
  // ^CharacterDevice
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
 
  virtual const char* purpose() const override { return class_name(); }

diff --git a/Kernel/Devices/SerialDevice.cpp b/Kernel/Devices/SerialDevice.cpp
@@ -45,7 +45,7 @@ bool SerialDevice::can_read(const FileDescription&, size_t) const
  return (get_line_status() & DataReady) != 0;
 }
 
-ssize_t SerialDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> SerialDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
  if (!size)
  return 0;
@@ -63,7 +63,7 @@ bool SerialDevice::can_write(const FileDescription&, size_t) const
  return (get_line_status() & EmptyTransmitterHoldingRegister) != 0;
 }
 
-ssize_t SerialDevice::write(FileDescription&, size_t, const u8* buffer, ssize_t size)
+KResultOr<size_t> SerialDevice::write(FileDescription&, size_t, const u8* buffer, size_t size)
 {
  if (!size)
  return 0;

diff --git a/Kernel/Devices/SerialDevice.h b/Kernel/Devices/SerialDevice.h
@@ -43,9 +43,9 @@ class SerialDevice final : public CharacterDevice {
 
  // ^CharacterDevice
  virtual bool can_read(const FileDescription&, size_t) const override;
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
  virtual bool can_write(const FileDescription&, size_t) const override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
 
  enum InterruptEnable {
  LowPowerMode = 0x01 << 5,

diff --git a/Kernel/Devices/ZeroDevice.cpp b/Kernel/Devices/ZeroDevice.cpp
@@ -44,16 +44,16 @@ bool ZeroDevice::can_read(const FileDescription&, size_t) const
  return true;
 }
 
-ssize_t ZeroDevice::read(FileDescription&, size_t, u8* buffer, ssize_t size)
+KResultOr<size_t> ZeroDevice::read(FileDescription&, size_t, u8* buffer, size_t size)
 {
- ssize_t count = min(static_cast<ssize_t>(PAGE_SIZE), size);
- memset(buffer, 0, (size_t)count);
+ ssize_t count = min(static_cast<size_t>(PAGE_SIZE), size);
+ memset(buffer, 0, count);
  return count;
 }
 
-ssize_t ZeroDevice::write(FileDescription&, size_t, const u8*, ssize_t size)
+KResultOr<size_t> ZeroDevice::write(FileDescription&, size_t, const u8*, size_t size)
 {
- return min(static_cast<ssize_t>(PAGE_SIZE), size);
+ return min(static_cast<size_t>(PAGE_SIZE), size);
 }
 
 }
diff --git a/Kernel/Devices/ZeroDevice.h b/Kernel/Devices/ZeroDevice.h
@@ -38,8 +38,8 @@ class ZeroDevice final : public CharacterDevice {
 
 private:
  // ^CharacterDevice
- virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) override;
- virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) override;
+ virtual KResultOr<size_t> read(FileDescription&, size_t, u8*, size_t) override;
+ virtual KResultOr<size_t> write(FileDescription&, size_t, const u8*, size_t) override;
  virtual bool can_read(const FileDescription&, size_t) const override;
  virtual bool can_write(const FileDescription&, size_t) const override { return true; }
  virtual const char* class_name() const override { return "ZeroDevice"; }

diff --git a/Kernel/DoubleBuffer.cpp b/Kernel/DoubleBuffer.cpp
@@ -58,21 +58,21 @@ void DoubleBuffer::flip()
  compute_lockfree_metadata();
 }
 
-ssize_t DoubleBuffer::write(const u8* data, ssize_t size)
+size_t DoubleBuffer::write(const u8* data, size_t size)
 {
  if (!size)
  return 0;
  ASSERT(size > 0);
  LOCKER(m_lock);
- ssize_t bytes_to_write = min(static_cast<size_t>(size), m_space_for_writing);
+ size_t bytes_to_write = min(size, m_space_for_writing);
  u8* write_ptr = m_write_buffer->data + m_write_buffer->size;
  m_write_buffer->size += bytes_to_write;
  compute_lockfree_metadata();
  memcpy(write_ptr, data, bytes_to_write);
  return bytes_to_write;
 }
 
-ssize_t DoubleBuffer::read(u8* data, ssize_t size)
+size_t DoubleBuffer::read(u8* data, size_t size)
 {
  if (!size)
  return 0;
@@ -82,7 +82,7 @@ ssize_t DoubleBuffer::read(u8* data, ssize_t size)
  flip();
  if (m_read_buffer_index >= m_read_buffer->size)
  return 0;
- ssize_t nread = min((ssize_t)m_read_buffer->size - (ssize_t)m_read_buffer_index, size);
+ size_t nread = min(m_read_buffer->size - m_read_buffer_index, size);
  memcpy(data, m_read_buffer->data + m_read_buffer_index, nread);
  m_read_buffer_index += nread;
  compute_lockfree_metadata();