linux

PostmarketOS Turns 600 Days Old

January 17, 2019 by 17 Comments

PostmarketOS began work on a real Linux distribution for Android phones just over 600 days ago. They recently blogged about the state of the project and ensured us that the project is definitely not dead.

PostmarketOS’ overarching goal remains a 10 year life-cycle for smartphones. We previously covered the project on Hackaday to give an introduction. Today, we’ll concern ourselves with the progress the PostmarketOS team has made.

The team admits that they’re stuck in the proof-of-concept phase, and need to break out of it. This has required foundational changes to the operating system to enable development across a wide variety of devices and processor architectures. There’s now a binary package repository powered by builds.sr.ht which will allow users to install packages for their specific device.

Other updates include fixing support for the Nexus 5 and Raspberry Pi Zero, creating support for open source hardware devices including the Pine A64-LTS and Purism Librem 5. PostmarketOS now boots on a total of 112 different devices.

We’re excited to see the PostmarketOS project making progress. With the widespread move to mobile devices, users lose control over their computing devices. PostmarketOS gives us the ability to run code that we can read and modify on these devices. It’s no small feat though. Supporting the wide variety of custom hardware in mobile devices requires a lot of effort.

While it may be a while before PostmarketOS is your daily driver, the project is well suited to building task-specific devices that require connectivity, a touch screen, and a battery. We bet a lot of Hackaday readers have a junk drawer phone that could become a project with the help of PostmarketOS.

Linux Fu: The Kitchen Sync

January 10, 2019 by 12 Comments

One of the great things about Linux and similar operating systems is they are configurable. If you don’t like something, there’s a great chance you can change it easily with a few entries in a file somewhere. For example, take bash — a very popular shell by any measure. If you want a different style of command line editing, there’s an option. You want the tab key to match files regardless of case? Another option. Usually, these are set in one of your so-called profile files like .bashrc in your home directory.

As long as you are sitting in front of your single computer working, this is great. You customize your .bashrc and other files to your heart’s content and then you work in an environment that acts the way you want it to. The problem is when you have a lot of computers. Maybe you have a web server, a desktop, a firewall machine, and a few dozen Raspberry Pi computers. How do you keep all the configurations the same? Then once they are the same, how do you keep them up to date?

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35C3: Safe And Secure Drivers In High-Level Languages

December 31, 2018 by 12 Comments

Writing device drivers is always a good start for a journey into the Linux kernel code. Of course, the kernel is a highly complex piece of software, and if you mess up your code properly, you might take down the entire system with you. User-space drivers on the other hand might not look as good on your CV, but they can help to work around some of the dangers and complexity of the kernel space. Plus, you don’t necessarily have to limit yourself to C to write them, especially if you are concerned about the usual C pitfalls and the security issues they can lead to.

With that in mind, [Paul Emmerich] is researching the concept of Linux user-space drivers for Intel’s 10Gbit network cards using other high-level languages, and recruits his students to write their final theses about the implementation details of as many languages as possible.

At last year’s 34c3, [Paul] already demonstrated the basics of writing such a user-space network driver for Linux, which serves now as reference implementation for his students. We won’t see Bash or JavaScript here, but we will see a brief summary of what it generally means to develop user-space drivers in C#, Swift, OCaml, or Haskell, along a more detailed insight from [Sebastian Voit] and [Simon Ellmann] about Go and Rust. A collection of each language’s implementation can be found on GitHub.

Since some of these languages bring their own memory handling and perform unpredictable garbage collection, performance and latency are two big topics to cover here. But then, the general concept is language-independent, so even if nothing in the world could ever make you give up on C, you might at least take away some new ideas for driver development.
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Linux Fu: Share Terminal in Browser

December 21, 2018 by 19 Comments

The title of this post says it all: GoTTY is a program that lets you share Linux terminal applications into a web browser. It is a simple web server written in Go that runs a non-GUI program and can push it out a socket in such a way that a browser can display it and, optionally, let the user interact with it.

With the emphasis on security these days, that ought to alarm you. After all, why would you want a shell running in a browser? Hang on, though. While that is possible — and not always undesirable — the real value to this technique is to run a specific command line program in a browser window. Here’s a use case: You want users to remotely monitor a system using top (or htop, if you are fancy). But you don’t want users logging into the system nor do you want to require them to have ssh clients. You don’t want to install monitoring tools, just use what you already have.

If you could get the output from top to show up in a browser window — even if the users had no ability to input — that would be an easy solution. Granted, you could just run top in batch mode, collect the output, and write it somewhere that a web server could find it. Assuming you have a web server installed, of course. But then what if you did want some other features like taking command line options or having the option for (hopefully) authenticated users to interact with the software? Now that would be more complicated. With GoTTY, it is easy.

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The Space Station has a Supercomputer Stowaway

December 10, 2018 by 58 Comments

The failed launch of Soyuz MS-10 on October 11th, 2018 was a notable event for a number of reasons: it was the first serious incident on a manned Soyuz rocket in 35 years, it was the first time that particular high-altitude abort had ever been attempted, and most importantly it ended with the rescue of both crew members. To say it was a historic event is something of an understatement. As a counterpoint to the Challenger disaster it will be looked back on for decades as proof that robust launch abort systems and rigorous training for all contingencies can save lives.

But even though the loss of MS-10 went as well as possibly could be expected, there’s still far reaching consequences for a missed flight to the International Space Station. The coming and going of visiting vehicles to the Station is a carefully orchestrated ballet, designed to fully utilize the up and down mass that each flight offers. Not only did the failure of MS-10 deprive the Station of two crew members and the experiments and supplies they were bringing with them, but also of a return trip which was to have brought various materials and hardware back to Earth.

But there’s been at least one positive side effect of the return cargo schedule being pushed back. The “Spaceborne Computer”, developed by Hewlett Packard Enterprise (HPE) and NASA to test high-performance computing hardware in space, is getting an unexpected extension to its time on the Station. Launched in 2017, the diminutive 32 core supercomputer was only meant to perform self-tests and be brought back down for a full examination. But now that its ticket back home has been delayed for the foreseeable future, NASA is opening up the machine for other researchers to utilize, proving there’s no such thing as a free ride on the International Space Station.

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Linux Fu: Turn a Web App into a Full Program

December 5, 2018 by 64 Comments

I hate to admit it. I don’t really use Linux on my desktop anymore. Well, technically I do. I boot into Linux. Then I do about 95% of my work in Chrome. About the only native applications I use anymore are development tools, the shell, emacs, and GIMP. If I really wanted to, I could probably find replacements for nearly all of those that run in the browser. I don’t use it, but there’s even an ssh client in the browser. Mail client? Gmail. Blogging? WordPress. Notes? OneNote or Evernote. Wouldn’t it be great to run those as actual applications instead of tabs in a browser? You can and I’ll show you how.

Having apps inside Chrome can be a real problem. I wind up with dozens of tabs open — I’m bad about that anyway. Restarting chrome is a nightmare as it struggles to load 100 tabs all at once. (Related tip: Go to chrome://flags and turn “Offline Auto-Reload Mode” off and “Only Auto-Reload Visible Tabs” on.) I also waste a lot of time searching since I try to organize tabs by window. So I have to find the window that has, say, Gmail in it and then find Gmail among the twenty or so tabs in that window.

What I want is a way to wrap web applications in their own window so that they’d show up in the task bar with their own icon, but external web pages that open from these apps ought to open in Chrome rather than in the same window. If applications were outside of the single browser window, I could move them to different desktops and organize them like they were any other program, including adding them to a launcher. Hopefully, this would let me have fewer windows like this:

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Linux as a Library: Unikernels are Coming

November 18, 2018 by 47 Comments

If you think about it, an operating system kernel is really just a very powerful shared library that offers services to many programs. Of course, it is a very powerful library, but still — its main purpose is to provide services to programs. Your program probably doesn’t use all of the myriad services the kernel provides. Even a typical system might not fully use all the things that are in a typical kernel. Red Hat has a new initiative to bring a technology called unikernels to the forefront. A unikernel is a single application linked with just enough of the kernel for it to execute. As you might expect, this can result in a smaller system and better security.

It can also lead to better performance. The unikernel doesn’t have to maintain devices and services that are not used. Also, the kernel and the application can run in the same privilege ring. That may seem like a security hole, but if you think about it, the only reason a regular kernel runs at a higher privilege is to protect itself from a malicious application modifying the kernel to do something bad to another application. In this case, there is no other application.

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