Luna/kernel/src/sys/stdio.cpp

#define MODULE "stdio"

#include "errno.h"
#include "interrupts/Context.h"
#include "io/Serial.h"
#include "log/Log.h"
#include "render/TextRenderer.h"
#include "thread/Scheduler.h"
#include "thread/Task.h"

#define STDIO_FAIL(function, error) kwarnln("%s failed with %s", #function, #error)

void sys_write(Context* context, const char* addr, size_t size)
{
    context->rax = size;
    TextRenderer::write(addr, size);
}

void sys_open(Context* context, const char* filename, int flags)
{
    Task* current_task = Scheduler::current_task();
    int fd = -1;
    for (fd = 0; fd < TASK_MAX_FDS; fd++)
    {
        if (!current_task->files[fd].is_open()) break;
    }
    if (fd == -1)
    {
        STDIO_FAIL(open, EMFILE);
        context->rax = -EMFILE;
        return;
    }
    VFS::Node* node = VFS::resolve_path(filename);
    if (!node)
    {
        STDIO_FAIL(open, ENOENT);
        context->rax = -ENOENT;
        return;
    }
    current_task->files[fd].open(node,
                                 (bool)flags); // FIXME: Implement more flags. (right now, 1 is can_read, 0 is not)
    context->rax = fd;
    return;
}

void sys_read(Context* context, int fd, size_t size, char* buffer)
{
    if (!buffer)
    {
        STDIO_FAIL(read, EINVAL);
        context->rax = -EINVAL;
        return;
    }
    if (fd >= TASK_MAX_FDS)
    {
        STDIO_FAIL(read, EBADF);
        context->rax = -EBADF;
        return;
    }
    if (fd < 0)
    {
        STDIO_FAIL(read, EBADF);
        context->rax = -EBADF;
        return;
    }
    Task* current_task = Scheduler::current_task();
    if (!current_task->files[fd].is_open())
    {
        STDIO_FAIL(read, EBADF);
        context->rax = -EBADF;
        return;
    }
    if (!current_task->files[fd].can_read())
    {
        STDIO_FAIL(read, EBADF);
        context->rax = -EBADF;
        return;
    }
    ssize_t result = current_task->files[fd].read(size, buffer);
    context->rax = (size_t)result;
    return;
}

void sys_close(Context* context, int fd)
{
    if (fd >= TASK_MAX_FDS)
    {
        STDIO_FAIL(close, EBADF);
        context->rax = -EBADF;
        return;
    }
    if (fd < 0)
    {
        STDIO_FAIL(close, EBADF);
        context->rax = -EBADF;
        return;
    }
    Task* current_task = Scheduler::current_task();
    if (!current_task->files[fd].is_open())
    {
        STDIO_FAIL(close, EBADF);
        context->rax = -EBADF;
        return;
    }
    current_task->files[fd].close();
    context->rax = 0;
    return;
}