Swift cross compile to single linux binary - swift

Is it possible to compile a swift binary from an OS X computer so that it runs on a server running Linux as a single binary without no extra libraries that need to be dynamically linked?
I'm thinking something like passing a -target to the swift command and passing another parameter to let it statically link all dependencies, but I'm not sure what the exact commands are.
The exact value for -target seems to be rather elusive.
Do I need to know the exact target distribution to be able to pass the correct string to the -target parameter?

From reading the sources on github
target would be Linux
machine would be x86_64
This gets called by the primary build script
This how ever answers a part of the question
The exact value for -target seems to be rather elusive.
Install a GCC toolchain for Mac OSX that can retarget Linux, one repo that I can see is OSXCross, for example.
Supply the values to the environment variables to GCC prior to running the script, that references that toolchain.
Unfortunately, that does not guarantee it will work, but give it a try and see what happens.

Is it possible to compile a swift binary from an OS X computer so that it runs on a server running Linux as a single binary without no extra libraries that need to be dynamically linked?
The short answer? Of course it is! Anything is possible when you put your heart to it!
Is it efficient? Inherently, no.
While I'm sure everyone here is familiar with what a compiler does, for the sake of this question and its newest of users, a compiler is an application that converts human readable code and maps it to a binary format that a computer can understand. However it should be worth mentioning that not all computers are the same. Each computer operating system has a different binary mapping than the other so a simple operation like copying values could be expressed as 1010 on one machine, and 0101 on another. As stated before in many questions prior, and for example this one, many programming languages are buildable across a variety of machines, but very few of them are portable across them because each computer has a different binary mapping.
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So how do we fix this?
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Well there are a number of solutions to fix this. The most obvious
method is to simply make your environment the target environment and
build your program to your hearts content. You obviously already did
this through a virtual machine and this typically what many
developers will do. This is by far the easiest solution but it
defeats the purpose of the question where you want to simply build
from your OSX machine.
Earlier you said you heard people talking about compiling windows programs on linux machines. Cygwin is a a development platform aimed at obtaining the windows framework that is not normally present on linux machines and allows many programs to be built with the windows framework in mind. However all its doing is adding binaries so that the compiler has some proper places to map to when windows only commands are found within a configuration. All its doing is introducing the binary configurations necessary for a program to successfully be ported over. This ties into the second option.
Secondly comes a compiler that supports cross platform compilation.
While I am currently uninformed and/or unfamiliar with such
compilers, this is technically a valid solution but would I call it
reliable? Probably not. If anything you're just adding more work to
your compiler as not only does it have to correctly map the syntax of
one computer program for one computer, it has to waste time linking
it to the new binaries. Additionally you would need to have the
compiler remember these linking's which could entail more wasted
memory space for having this one compiler.
Even then, systems like these are few and far between and whether its guaranteed to work depends upon how well the compilers maintainer knows their stuff, how frequently they update it etc. etc. And the chances that they even performed to correct mappings of binaries in the first place is not something I'd stake my life on.
The third and perhaps most ideal solution is to look into container technologies such as docker. Their containers are essentially ways for you to build your app and port it to new machines without having to change or modify anything about how you build and compile it. Simply build one, store it in a container, port it to your machine of choice and integrate it into your current project. Come to think of it, container systems like docker were built to prevent the very thing that you are currently experiencing, where you have a source code working on your one machine but no place else. Something like docker will be able to run your code on any machine without having to recompile it for each new machine.
Docker provides an interesting framework for container to container communication, application examples and has a fairly straightforward documentation that it would be worthwhile to look at to see if your project could have some of its parts ported to docker.
This being said, there are multiple ways to fix the issue you are currently facing, so as you being a software engineer, its up to you in what would be the most ideal way of handling your project.
// EDIT //
Will edit this to be a better response once im not drop-dead tired.

Related

How can I detect the frameworks and/or libraries used in any Source Code Repository/Directory programatically?

Suppose I have a source code directory, I want to run a script that would scan the code in the directory and return the languages, frameworks and libraries used in it. I've tried github/linguist, its a great tool which even Github uses to detect the programming languages used in a source code, however I am not able go beyond that and detect the framework exactly.
I even tried tools like it-depends, to fetch the dependencies but, its getting messed up.
Could someone help me out to figure out how I can do this stuff, with an existing tool or if have to make one such tool how should I approach it.
Thanks in Advance
This is, in the general case, impossible. The halting problem precludes any program from being able to compute, in finite time, what other programs may or may not do - including what dependencies it requires to run. Sure, you can make it work for some inputs - but never for all.
So you have to compromise:
which languages do you need to support? it-depends does not try to support Java, for example. Different languages have different ways of calling in dependencies from their source-code. For example, if working with C, you will want to look at #includes.
which build-chains to you need to support? parsing a standard Makefile for C is very different from, say, looking into a Maven pom.xml for Java. Additionally, build-chains can perform arbitrary computation -- and again, due to the halting problem, your dependency-detection program will not be able to "statically" figure out intended behavior. It is entirely possible to link against one library or another one (or none at all) depending on what is detected to exist. What should you output in this case?. For programs that have no documented build process, you simply cannot know their dependencies. Often, the build-process is human-documented but not machine-readable...
what do you consider a library/framework? long-lived libraries can evolve through many different versions, and the fact that one version is required and not another may not be explicit in the source-code. If a code-base depends on behavior found in only a specific, now superseded, version of a library, and no explicit mention of that version is found -- your dependency-detection program will have no way to know about it (unless you code in library-version-specific detection; which is doable, but on a case-by-case basis, and requires deep knowledge of differences between versions).
Therefore the answer to your question is that... it depends (they go into a fair amount of detail regarding limitations). For the specific case of Java + Maven, which is not covered by it-depends, you can use Maven itself, via mvn dependency:tree. Choose a subset of the problem instead of trying to solve it all at once.

How to determine present operating system (including specific distribution in the case of Linux) in a Vala program?

I am interested in writing a Vala program that will determine the present operating system and act accordingly (exactly how it will act I have not decided yet, but is not relevant to this question). So what I would like to know is how I might determine the present operating system (including the specific distribution in the case of Linux) in a Vala program at runtime.
Unless you are writing system level code (like package manager or OS configuration code), you shouldn't. A much better alternative is to use a library that already abstracts the distribution specifics for you.
If you absolutely have to there are two main ways to do it:
At build time
Here your build system should be responsible to detect the OS / distribution and either pass a define to the compiler (like -DDISTRO_UBUNTU) or write a config.vala file (possibly from a template config.vala.in with replacements, e.g. autotools has the AC_CONFIG_FILES facility to do this).
At runtime
Here your tool does the detection itself when it's running.
Which fits your application better is a design choice.
As to how to do it there are several things you can check:
uname -a (or other parameters, see man uname) will give you the kernel that is currently running.
lsb_release -a (not available on every distro, sometimes an optional package which you might have a package dependency to) will give you information on what distro and what distro version you are running on.
On Debian/Ubuntu derivates there is a file called /etc/debian_version which gives an indication of what release is currently installed. That information is not totally accurate though.
Some people are trying to read /etc/issue, but that is dangerous, since that file could be modified by the admin / the user.
You could ask the user which OS she is running.
There are also some os info libraries that you could use.
You might use the uname(2) syscall (how to do that in Vala is left as an exercise to the user), or read /proc/version (see proc(5)), or read /etc/issues or follow Linux Standard Base conventions (e.g.popen the output of lsb_release -a).
But as Jens Mühlenhoff answered, you should not do that, and avoid writing code depending on some particular distribution.
And some users might want to fake or hide that information (think of someone having some "Linux From Scratch" system).

Built-in scripting language available on all major operating systems?

Does anyone know of a scripting language that's included with most platforms (say Mac/Windows/Linux)? I haven't been able to find one. So far javascript in web browsers or compiled java are about it. Jython comes close.
My goal is to be able to download a file from the web or portable storage and just run it, without having to install something first, or have special user permissions, or edit it, or rename it, or give it executable privilages. It would give you access to generally accepted metaphors in computing: input, output, persistent storage, time, spawning tasks, sockets, fixed and floating point math, unicode, etc. Ideally it would abstract away minutia like line endings, endianness, and yielding for other processes.
I don't want to get into why having a universal language/virtual machine is important, or at the very least, useful. I feel that we are missing a middleware above the operating system level, something like POSIX but less esoteric, and without it, we all are forced to spend a disproportionate amount of time reinventing the wheel or writing special cases. For me, availability and a complete feature set are more important than speed (which could come later).
Thanks in advance for any insights you can provide,
Zack Morris
You will be able to run carefully written sh scripts on almost all unix systems.
If you want to add Microsoft systems, then it is more difficult, but still possible to provide a single script file, that will "autodetect" the interpreter it's running on and select between a sh part and a command.com or whatever they have on Microsoft systems.
Once you can run a script on a known system you can further download or unpack and install automatically whatever software you need.

Is writing plug in for eclipse dependent on operating system?

we start to write plug in for eclipse to work with some java frame work like hadoop (we want to edit hadoop eclipse plug in and merge it with other. our plug in must work in Linux operating system. Generally writing plug in for eclipse depend on operating system or not? if depend what benefits to write it for Linux?
Well, the previous answer is correct... in most cases. You should specifically check all the interfaces with the operating system.
SWT is a Java wrapper over native OS widgets. It behaves almost the same on all OSs, but not exactly. There are subtleties. For example, events that might be fired a bit differently, drawing of widgets, etc. My experience shows that you have to check on all OSs to be sure that it works as it should, especially if you are doing more complex UI rendering. In many cases I had to do some fine tuning to get it right. It is not a great deal of effort, but it should be considered.
Another issue is working with the file system. For example, make sure you are composing files paths correctly. It is always a good idea to test that part as well.
Eclipse plugins are platform independent (you are writing them in Java), unless your plugin requires some low-level calls to the operating system (i.e. JNI) or to invoke some tool found only in the Linux OS.
The only part of Eclipse tied - in part - to the OS is the SWT toolkit, since it's optimized for the graphic environment you are running it, but if Eclipse can run in the OS you are interested in, you should not be bothered by this.

Developing an operating system for the x86 architecture [closed]

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I am planning to develop an operating system for the x86 architecture.
What options of programming languages do I have?
What types of compilers are there available, preferably on a Windows environment?
Are there any good sources that will help me learn more about operating system development?
Is it better to test my operating system on a Virtual Machine or on physical hardware?
Any suggestions?
For my final year project in collage I developed a small x86 OS with a virtual memory manager, a virtual file system and fully preemptive multitasking. I made it open source and the code is heavily commented, check out its source forge page at:
https://github.com/stephenfewer/NoNameOS
From my experience I can recommend the following:
You will need x86 assembly language for various parts, this in unavoidable, but can be kept to a minimum. Fairly quickly you will get running C code, which is a proven choice for OS development. Once you have some sort of memory manager available you can go into C++ if you like (you need some kind of memory manager for things like new and delete).
No matter what language you choose you will still need assembly & C to bring a system from boot where the BIOS leaves you into any useable form.
Ultimately, the primary language you choose will depend on the type of OS you want to develop.
My development environment was the Windows port of the GNU development tools DJGPP along with the NASM assembler. For my IDE I used IBM's Eclipse with the CDT plugin which provides a C/C++ development environment within Eclipse.
For testing I recommend BOCHS, an open source x86 PC emulator. It lets you boot up your OS quickly which is great for testing and can be integrated into eclipse so you can build and run your OS at the push of a button. I would also recommend using both VMWare and a physical PC occasionally as you can pick up on some subtle bugs that way.
P.S. OS development is really fun but is very intensive, mine took the best part of 12 months. My advice is to plan well and your design is key! enjoy :)
Language and compiler depend entirely on what you're attempting to accomplish. I would suggest, though, that you might be approaching the problem from too low a level.
There are materials out there on operating system fundamentals. MIT has OpenCourseware on the subject. Read through Andrew Tannenbaum's Operating Systems series, and look at things like Minix.
Get an idea for what's out there. Start tinkering with things. Borrow ideas, and see where they go. You can reinvent the wheel if you really want, but you'll learn more by building on the works of others.
It doesn't really matter, what language you choose. If the language is Turing-complete, then you can write an OS in it.
However, the expressiveness of the language will make certain kinds of designs very easy or very hard to implement. For example, the "liveliness" and dynamism of the old Smalltalk OSs depends on the fact that they are implemented in Smalltalk. You could do that in C, too, but it would probably be so hard that you wouldn't even think about it. JavaScript or Ruby OTOH would probably be a great fit.
Microsoft Research's Singularity is another example. It simply couldn't be implemented in anything other than Sing#, Spec# and C# (or similar languages), because so much of the architecture is dependent on the static type safety and static verifiability of those languages.
One thing to keep in mind: the design space for OSs implemented in C is pretty much fully explored. There's literally thousands of them. In other languages, however, you might actually discover something that nobody has discovered before! There's only about a dozen or so OSs written in Java, about half a dozen in C#, something on the order of two OSs in Haskell, only one in Python and none in Ruby or JavaScript.
Try writing an OS in Erlang or Io, and see how that influences your thinking about Operating Systems!
There is an OS course offered at the University of Maryland that utilizes GeekOS. This is a small, extensively commented OS designed for educational purposes which can be run using the Bochs or QEMU emulators.
For an example of how it is used in a course, check out a previous offering of the course at the class webpage. There, you will find assignments where you have to add different functionality to GeekOS.
Its a great way to get familiar with a small and simple OS that runs on the x86 architecture.
You might want to look up XINU. it's a tiny OS for x86 that isn't really used for anything other than to be dissected by students.
Use ANSI C, and start off with an emulator.
When you port over to a real machine, there will be some assembler code. Context switching and interrupt handling (for instance) is easier to write in assembler.
Andy Tannenbaum has written a good book on OS. Many other good ones exist.
Good luck! There is nothing quite like haveing written your own OS, however small.
Also check out the OSDev.org which have all information you need to get started.
I've done that once for a 386SX, which was on a PCI board. A good source on how to start a X86 cpu in protected mode is the source code of linux. It's just a few assembly statements. After that you can use gcc to compile your C code. The result is objectcode in ELF format. I wrote my own linker, to make a program out of the objectcode. And yes, it worked! Good luck.
Be sure to check out the answers to my question:
How to get started in operating system development
Without a doubt, I'd use Ada. It's the best general-purpose systems-programming language I have come across, bar none. One example, Ada's much better for specifying bit layout of objects in a record than C. Ada also supports overlaying records on specific memory locations. C requires you to play with pointers to acheive the same effect. That works, but is more error-prone. Ada also has language support for interrupts.
Another: Safety. Ada defaults to bound checking array assignments, but allows you to turn it off when you need it. C "defaults" to no bound checking on arrays,so you have to do it yourself manually whenever you want it. Time has shown that this is not the right default. You will forget one where it is needed. Buffer overflow exploits are the single most common security flaw used by crackers. They have whole websites explainng how to find and use them.
As for learning about doing this, the two books I'm aware of are XINU (Unix backwards, nothing to do with Scientology), and Project Oberon. The first was used in my Operating Systems graduate course, and the second was written by Nikalus Wirth, creator of Pascal.
If you are making a full OS, you will need to use a range of languages. I would expect Assembly, C and C++ at the very least.
I would use a Virtual Machine for most of the testing.
C most probably...all major OS-es have been written in C/C++ or Objective-C(Apple)
If you want write an OS then you need a couple of people. A OS can not write a single people. I think it is better to work on existing OS projects
Reactos --> C, Assembler
SharpOS --> C#
JNode --> Java
This is only a short list of OS projects. How you can see there is a project for every possible language.