This week I’ve decided to skip trying to get GDB working for now (there are so many issues it’ll take forever to solve them), and instead decided to finally give focus to the final concerns I had about ptrace. Most changes this week was related to getting decent behavior of child processes, although the design feels… suboptimal, somehow (not sure why), so I feel I must be able to improve it better later.
Another change was security: Tracers running as a non-root user can now in addition to only tracing processes running as the same user, only trace processes that are directly or indirectly children of the tracer. In the future this can easily be allowed with some kind of capability, but currently in Redox there isn’t a capability-like system other than the simple (but really powerful) namespacing system which sadly I don’t think can be used for this.
Posts about using Rust to build all or part of an operating system.
Once again, last weeks action was merged, which means the full ptrace feature was merged, and it’s time to start tackling the final issues which I have delayed for so long. But, before that, I decided to try to get some basic ptrace compatibility in relibc, so we could see just how far away software like gdb is from being ported, and what concerns I haven’t thought about yet. redox-nix update: That said, I took a little break from the madness, to instead lay my focus on another interesting problem: Newer redoxer couldn’t be compiled using carnix, because of some dependency that used a cargo feature carnix didn’t support. Let me first explain what carnix is, and why this is a problem.
Before I dive in to this week’s actions, I am pleased to announce that all the last weeks’ work is merged! This merge means you can now experiment with basic ptrace functionality using only basic registers and PTRACE_SYSCALL/PTRACE_SINGLESTEP. I have already opened the second PR in the batch: Ptrace memory reading and floating point registers support which will supply the “final bits” of the initial implementation, before all the nitpicking of final concerns can start (not to underestimate the importance and difficulty of these nitpicks - there are some areas of ptrace that aren’t even thought about yet and those will need tending to)! I will comment on these changes in this blog post, as there are some interesting things going on!
Wrapping up the Ion as a library project. It is now possible to embed Ion in any Rust application. Ion takes any Read instance and can execute it (so yes, it is possible to run Ion without ever collecting the script’s binary stream). It takes care of expanding the input and managing the running applications in an efficient manner, with a comprehensive set of errors. Ion is now the rust-based, pipe-oriented liblua alternative.
The next step in the journey of ptrace was to bite the bullet (or at least I thought) and implement system-call tracing. Since the kernel must be able to handle system-calls of processes, it’s quite obvious that the way to set a breakpoint should involve the kernel, running in the context of the tracee, should notify the tracer and wait. So the biggest challenge would be to figure out how kernel synchronization worked.
This post adds support for heap allocation to our kernel. First, it gives an introduction to dynamic memory and shows how the borrow checker prevents common allocation errors. It then implements the basic allocation interface of Rust, creates a heap memory region, and sets up an allocator crate. At the end of this post all the allocation and collection types of the built-in alloc crate will be available to our kernel.
After having a pretty clear goal to meet specified by the RFC, time to get things moving. I started with what I thought would be low hanging fruit: Reading the registers of another process. It ended up being more difficult than I thought, but it ended up being really interesting and I want to share it with you :)
I will quickly show how I got bindgen (https://rust-lang.github.io/rust-bindgen) to generate the bindings to Fuse (libfuse) with the current stable1 release of Rust. By doing so, this should demonstrate how to bootstrap writing your own Fuse file system in Rust.
I do realise that there are some crates that already exist that aid in making Fuse drivers in Rust, but this was more or less an excuse to also try out bindgen, which I don't believe those existing libraries utilise.
How to fetch batteries information from the macOS APIs with Rust
Manticore is a research operating system, written in Rust, with the aim of exploring the parakernel OS architecture.
The OS is increasingly a bottleneck for server applications that want to take maximum advantage of the hardware. Many traditional kernel interfaces (such as in POSIX) were designed when I/O was significantly slower than the CPU. However, today I/O is getting faster, but single-threaded CPU performance has stagnated. For example, a 40 GbE NIC can receive a cache-line sized packet faster than the CPU can access its last-level cache (LLC), which makes it tricky for an OS to keep up with packets arriving from the network. Similarly, non-volatile memory (NVM) access speed is getting closer to DRAM speeds, which challenges OS abstractions for storage.
To address this OS bottleneck, server applications are increasingly adopting kernel-bypass techniques. For example, the Seastar framework is an OS implemented in userspace, which implements its own CPU and I/O scheduler, and bypasses the Linux kernel as much as it can. Parakernel is an OS architecture that eliminates many OS abstractions (similar to exokernels) and partitions hardware resources (similar to multikernels) to facilitate high-performance server application with increased application-level parallelism and predictable tail latency.
This repository contains a simple KVM firmware that is designed to be launched from anything that supports loading ELF binaries and running them with the Linux kernel loading standard. The ultimate goal is to be able to use this "firmware" to be able to load a bootloader from within a disk image.
This post explores unit and integration testing in no_std executables. We will use Rust's support for custom test frameworks to execute test functions inside our kernel. To report the results out of QEMU, we will use different features of QEMU and the bootimage tool.
Recently, x86_64-unknown-uefi target was added into Rust mainline (https://github.com/rust-lang/rust/pull/56769). So, I tried to write UEFI application with this update. There exists an awesome crate, uefi-rs, which provides Rust interface for UEFI application. However, this is my first time to write UEFI application, so to understand what happens in it, I didn’t use any existing crate.
This post shows how to implement paging support in our kernel. It first explores different techniques to make the physical page table frames accessible to the kernel and discusses their respective advantages and drawbacks. It then implements an address translation function and a function to create a new mapping.
It has been one year and four days since the last release of Redox OS! In this time, we have been hard at work improving the Redox ecosystem. Much of this work was related to relibc, a new C library written in Rust and maintained by the Redox OS project, and adding new packages to the cookbook. We are proud to report that we have now far exceeded the capabilities of newlib, which we were using as our system C library before. We have added many important libraries and programs, which you can see listed below.
This will be the first in a series of weekly updates on progress made in the development of Pop!_OS. Thus, this will only contain content pertaining specifically to Pop!_OS, though at times there may be some overlap with the hardware side of System76.
I’ve decided to take a look at Minix, which is an interesting microkernel OS. Naturally after building Minix from git, the first thing I decided to try was porting Rust’s std to Minix so I could cross-compile Rust programs from Linux to run under Minix. Okay, I suppose I could have started with something else, but porting Rust software and modifying the platform-depending part of std is something I have experience with from working on Redox OS. And Rust really isn’t that hard to port.
We are going to make a demo linux web-server with systemd, config file and installable .deb binary in Rust.
This post introduces paging, a very common memory management scheme that we will also use for our operating system. It explains why memory isolation is needed, how segmentation works, what virtual memory is, and how paging solves memory fragmentation issues. It also explores the layout of multilevel page tables on the x86_64 architecture.
It has been a long-standing tradition to develop a language far enough to be able to write the language's compiler in the same language, and Rust does the same. Rust is nowadays written in Rust. We've tracked down the earlier Rust versions, which were written in OCaml, and were planning to use these to bootstrap Rust. But in parallel, John Hudge (Mutabah) developed a Rust compiler, called "mrustc", written in C++. mrustc is now good enough to compile Rust 1.19.0. Using mrustc, we were able to build Rust entirely from source with a bootstrap chain
In this post we set up the programmable interrupt controller to correctly forward hardware interrupts to the CPU. To handle these interrupts we add new entries to our interrupt descriptor table, just like we did for our exception handlers. We will learn how to get periodic timer interrupts and how to get input from the keyboard.
Stratis 1.0 was quietly released last week with the 1.0 version marking its initial stable release and where also the on-disk meta-data format has been stabilized. Red Hat engineers believe Stratis is now ready for more widespread testing.
Time for me to pack up and never ever contribute to Redox ever again… Just kidding. This isn’t goodbye, you can’t get rid of me that easily I’m afraid. I’ll definitely want to contribute more, can’t however say with certainty how much time I’ll get, for school is approaching, quickly
The previous blog post discusses how raw disk reads were implemented in the loader stub. The next step was to implement a clean read API which can be used by different filesystem libraries in order to read their respective filesystems. Since the raw reads from the BIOS interrupt had a granularity in terms of sectors(each sector being 512 bytes), the reads had to be translated in order to provide byte level granularity. The clone_from_slice function ensures that a direct call to memcopy is not required. The refined read function is here.
With the recent addition of Rust 1.27.0 in the HaikuPorts repository, I thought it would be good to do a short, public write-up of the current state of Rust on Haiku, and some insight into the future.
At the time of writing the previous blog the plan was to target the Raspberry Pi 3 (Cortex A53) as a development platform because of its availability, popularity and community. Sadly, it seems that Broadcom went through a lot of shortcuts while implementing this specific design, which means features like GIC are half-there or completely missing, like in this case.
After a discussion with @microcolonel, he proposed and kindly sent me a HiKey960 reference SoC from the awesome Linaro 96Boards initiative. The quality of this board is definitely a lot better than the Raspberry Pi and the documentation is detailed and open. Great stuff.
As promised in the previous article (thanks for all the valuable feedback ‒ I didn’t have the time to act on it yet, but I will), this talks about Unix signal handling.
Long story short, I wasn’t happy about the signal handling story in Rust and this is my attempt at improving it.
This is the second blog post about implementing a FAT32 filesystem in Redox.
Over the last couple of weeks, Nebulet has progressed signifigantly. Because of that, I think it’s time to talk about why I made certain decisions when designing and writing Nebulet.
All excited. A first calendar entry to describe my attempt on arm64 support in Redox OS. Specifically, looking into the Raspberry Pi2/3b/3+(all of them having a Cortex-A53 ARMv8 64-bit microprocessor, although for all my experiments I am going to use the Raspberry Pi 3b.
In this post we explore double faults in detail. We also set up an Interrupt Stack Table to catch double faults on a separate kernel stack. This way, we can completely prevent triple faults, even on kernel stack overflow.
In this post, we start exploring CPU exceptions. Exceptions occur in various erroneous situations, for example when accessing an invalid memory address or when dividing by zero. To catch them, we have to set up an interrupt descriptor table that provides handler functions. At the end of this post, our kernel will be able to catch breakpoint exceptions and to resume normal execution afterwards.
In this post we complete the testing picture by implementing a basic integration test framework, which allows us to run tests on the target system. The idea is to run tests inside QEMU and report the results back to the host through the serial port.
A first calendar entry to describe my attempt on ARM64 support in Redox OS. Specifically, looking into the Raspberry Pi2/3(B)/3+ (all of them having a Cortex-A53 ARMv8 64-bit microprocessor, although for all my experiments I am going to use the Raspberry Pi 3(B)).
Last week I ended off stating that the redox netstack might soon switch to an edge-triggered model. Well, I ended up feeling bad about the idea of letting others do my work and decided to stop being lazy and just do it myself.
Rust is an extremely interesting language for the development of system software. This was the motivation to evaluate Rust for HermitCore and to develop an experimental version of our libOS in Rust. Components like the IP stack and uhyve (our unikernel hypervisor) are still written in C. In addition, the user applications are still compiled by our cross-compiler, which is based on gcc and supports C, C++, Fortran, and Go. The core of the kernel, however, is now written in Rust and published at GitHub. Our experiences so far are really good and we are looking into possibly new Rust activities, e.g., the support for Rust’s userland.
This is a blog post about the work which I have done so far in implementing a FAT32 filesystem in Redox. Currently the Redox bootloader as well as the userspace filesystem daemon supports only RedoxFS.
This is the weekly summary for my Redox Summer of Code project: Porting tokio to redox. Most of the time was spent on one bug, and after that one was figured out and fixed it ended up being relatively easy! As of now, 11⁄13 tokio examples seem to work on redox. The remaining examples are UDP and seem to fail because of something either with the rust standard library or my setup.
This post explores unit testing in no_std executables using Rust's built-in test framework. We will adjust our code so that cargo test works and add some basic unit tests to our VGA buffer module.
Redox OS is running its own Summer of Code this year, after the Microkernel devroom did not get accepted into GSoC 2018. We are looking for both Students and Sponsors who want to help Redox OS grow. At the moment, Redox OS has $10,800 in donations from various platforms to use to fund students. This will give us three students working for three months, if each student requests $1200 per month on average as described in Payment.
In order to fund more students, we are looking for sponsors who are willing to fund RSoC. Donations can be made on the Donate page. All donations will be used to fund Redox OS activities, with about 90% of those over the past year currently allocated to RSoC.
Installing a toolchain for Rust is very easy, as support for CloudABI has been upstreamed into the Rust codebase. Automated builds are performed by the Rust developers. As there hasn’t been a stable release of Rust to include CloudABI support yet, you must for now make use of Rust’s nightly track.
Our second iteration of the 18.04 ISO is ready for testing. Testing the new installer and Optimus switching is our priority for this test release. Please test installing on a variety of hardware and provide feedback on any issues you encounter. If you run into any bugs, you can file them at https://github.com/pop-os/pop/issues.
Over the past six months we've been working on a second edition of this blog. Our goals for this new version are numerous and we are still not done yet, but today we reached a major milestone: It is now possible to build the OS natively on Windows, macOS, and Linux without any non-Rust dependendencies.
Writing eBPF tracing tools in Rust
I have been playing with eBPF (extended Berkeley Packet Filters), a neat feature present in recent Linux versions (it evolved from the much older BPF filters). It is a virtual machine running in th…