Add file syscalls

[vinc]

• Add file handle table to process
• Add open syscall
• Add close syscall
• Add read syscall
• Add write syscall
• Add stat syscall
• Add seek syscall
• Add delete syscall
• Add FileIO for dirs, files, and devices
• Add /dev/random
• Add /dev/console
• Read dirs from userspace

[vinc]

We can now do syscall::write(1, b"Hello, World\n") 🎉

[vinc]

Reading the RNG from the FS:

[vinc]

A lot of kernel functions called from userspace still remains:

> rg "sys::[^)]*?\(" src/usr -o --no-filename | sort | uniq -c | sort -h
      1 sys::acpi::shutdown(
      1 sys::allocator::memory_size(
      1 sys::allocator::memory_used(
      1 sys::ata::list(
      1 sys::console::cols(
      1 sys::console::drain(
      1 sys::console::rows(
      1 sys::fs::Dir::delete(
      1 sys::fs::disk_size(
      1 sys::fs::disk_used(
      1 sys::fs::format_ata(
      1 sys::fs::format_mem(
      1 sys::fs::is_mounted(
      1 sys::fs::mount_ata(
      1 sys::fs::mount_mem(
      1 sys::keyboard::set_keyboard(
      1 sys::process::env(
      1 sys::process::envs(
      1 sys::process::set_user(
      1 sys::process::user(
      1 sys::random::get_u64(
      1 sys::time::set_pit_frequency_divider(
      1 sys::vga::set_font(
      1 sys::vga::set_palette(
      2 sys::fs::File::delete(
      2 sys::process::set_dir(
      2 sys::process::set_env(
      3 sys::console::disable_echo(
      3 sys::console::enable_echo(
      3 sys::process::dir(
      4 sys::fs::Dir::create(
      4 sys::random::get_u16(
      5 sys::fs::File::create(
      7 sys::console::end_of_text(
      7 sys::fs::Dir::open(
      8 sys::net::IFACE.lock(
     10 sys::fs::File::open(

[vinc]

Most of the remaining methods will need to be replaced by device files:

   1 sys::acpi::shutdown(
   1 sys::allocator::memory_size(
   1 sys::allocator::memory_used(
   1 sys::ata::list(
   1 sys::console::cols(
   1 sys::console::drain(
   1 sys::console::rows(
   1 sys::fs::Dir::delete(
   1 sys::fs::File::create(
   1 sys::fs::disk_size(
   1 sys::fs::disk_used(
   1 sys::fs::format_ata(
   1 sys::fs::format_mem(
   1 sys::fs::is_mounted(
   1 sys::fs::mount_ata(
   1 sys::fs::mount_mem(
   1 sys::keyboard::set_keyboard(
   1 sys::process::env(
   1 sys::process::envs(
   1 sys::process::set_user(
   1 sys::process::user(
   1 sys::time::set_pit_frequency_divider(
   1 sys::vga::set_font(
   1 sys::vga::set_palette(
   2 sys::fs::File::delete(
   2 sys::process::set_dir(
   2 sys::process::set_env(
   3 sys::console::disable_echo(
   3 sys::console::enable_echo(
   3 sys::fs::Dir::create(
   3 sys::process::dir(
   6 sys::fs::Dir::open(
   7 sys::console::end_of_text(
   8 sys::net::IFACE.lock(