Luna/kernel/src/fs/FileDescriptor.cpp

#include "fs/FileDescriptor.h"
#include "std/errno.h"
#include "std/stdlib.h"
#include "sys/UserMemory.h"

Descriptor::Descriptor() : m_is_open(false)
{
}

Descriptor::Descriptor(const Descriptor& other)
    : m_is_open(other.m_is_open), m_can_read(other.m_can_read), m_can_write(other.m_can_write),
      m_able_to_block(other.m_able_to_block), m_close_on_exec(other.m_close_on_exec), m_node(other.m_node),
      m_offset(other.m_offset)
{
}

void Descriptor::open(VFS::Node* node, bool can_read, bool can_write, bool able_to_block, bool close_on_exec)
{
    m_can_read = can_read;
    m_can_write = can_write;
    m_able_to_block = able_to_block;
    m_close_on_exec = close_on_exec;
    m_node = node;
    m_offset = 0;
    m_is_open = true;
}

ssize_t Descriptor::read(size_t size, char* buffer)
{
    ssize_t result = VFS::read(m_node, m_offset, size, buffer);
    m_offset += result;
    return result;
}

ssize_t Descriptor::write(size_t size, const char* buffer)
{
    ssize_t result = VFS::write(m_node, m_offset, size, buffer);
    m_offset += result;
    return result;
}

ssize_t Descriptor::user_read(size_t size, char* buffer)
{
    char* buf = (char*)kmalloc(size);
    if (!buf) return -ENOMEM;
    ssize_t result = read(size, buf);
    if (!copy_to_user(buffer, buf, size)) result = -EFAULT;
    kfree(buf);
    return result;
}

ssize_t Descriptor::user_write(size_t size, const char* buffer)
{
    char* buf = (char*)kmalloc(size);
    if (!buf) return -ENOMEM;
    ssize_t result;
    if (!copy_from_user(buffer, buf, size)) result = -EFAULT;
    else
        result = write(size, buf);
    kfree(buf);
    return result;
}

#define MAP_FAIL(errno) 0xffffffffffffff00 | (unsigned char)(errno)

uintptr_t Descriptor::mmap(uintptr_t addr, size_t size, int prot, off_t offset)
{
    if (!m_node->mmap_func) return MAP_FAIL(ENOTSUP);
    return m_node->mmap_func(m_node, addr, size, prot, offset);
}

long Descriptor::ioctl(int cmd, uintptr_t arg)
{
    if (!m_node->ioctl_func) return MAP_FAIL(ENOTSUP);
    return m_node->ioctl_func(m_node, cmd, arg);
}

int Descriptor::seek(long offset)
{
    if (m_node->type == VFS_FILE && (uint64_t)offset > m_node->length)
        return -EINVAL; // FIXME: Support seeking beyond the current file's length.
    m_offset = (uint64_t)offset;
    return 0;
}

const Descriptor& Descriptor::operator=(const Descriptor& other)
{
    m_is_open = other.m_is_open;
    m_can_read = other.m_can_read;
    m_can_write = other.m_can_write;
    m_offset = other.m_offset;
    m_node = other.m_node;
    m_able_to_block = other.m_able_to_block;
    m_close_on_exec = other.m_close_on_exec;
    return other;
}