Updates in May 2019

This post gives an overview of the recent updates to the Writing an OS in Rust blog and to the used tools. I was quite busy with my master thesis this month, so I didn’t have the time to create new content or major new features. However, there were quite a few minor updates.

x86_64

• Use cast crate instead of usize_conversions crate (released as version 0.5.5).
• Make FrameAllocator an unsafe trait (released as version 0.6.0).
• Change Port::read and PortReadOnly::read to take &mut self (released as version 0.7.0).
• @npmccallum started working on moving the type declarations to a separate crate to make them usable for more projects. We created the experimental x86_64_types crate for this.

Cargo-Xbuild

• Make backtraces optional to remove the transitive dependency on the cc crate, which has additional compile-time requirements (e.g. a working gcc installation). These requirements caused problems for some people, so we decided to disable backtraces by default. Released as version 0.5.9.
• Error when the sysroot path contains spaces: This pull request adds a special error message that points to rust-lang/cargo#6139 when a sysroot path contains spaces. This should avoid the regular confusion, e.g. here, here, or here.
• Add a XBUILD_SYSROOT_PATH environment variable to override sysroot path: This feature is useful when the default sysroot path contains a space. Released as version 0.5.10.
• Fix the new XBUILD_SYSROOT_PATH environment variable. Released as version 0.5.11.
• Update Azure Pipelines CI script
  • Build all branches instead of just master and the bors staging branch.
  • Rustup is now included in the official Windows image of Azure Pipelines, so we don’t need to install it again.

Bootloader

• @rybot666 started working on porting the 16-bit assembly of the bootloader to Rust.

Bootimage

• @toothbrush7777777 landed a pull request to pad the boot image to a hard disk block size. This is required for booting the image in VirtualBox. Released as version 0.7.4.
• Set XBUILD_SYSROOT_PATH when building bootloader. Released as version 0.7.5.

Blog OS

• Update to version 0.6.0 of x86_64, which made the FrameAllocator trait unsafe to implement.
• Use -serial stdio instead of -serial mon:stdio as QEMU arguments when testing.
• Update x86_64 to version 0.7.0, which changed the Port::read method to take &mut self instead of &self.
• @josephlr replaced some leftover tabs with spaces.
• Rewrite CompareMessage struct to check the whole string.