Windows exec format error



Fixing exec format errors with Docker ENTRYPOINT Scripts on Windows

You may have gotten cryptic errors when trying to use ENTRYPOINT scripts in your images while running Windows. Here’s how to fix them.

Docker ENTRYPOINT scripts are a wonderful thing, but it’s not so wonderful when they start failing in unexpected ways, especially when you’re very confident that “identical” ENTRYPOINT scripts worked on other Docker hosts.

Does This Error Look Familiar?

standard_init_linux.go:195: exec user process caused «exec format error»

I’m not someone who hacks on the Docker code base itself but when I encountered this error, the exec caught my eye. I thought “hmm, well I’m using exec «$@» in my entrypoint, maybe something is wrong with that?”.

But I knew there wasn’t much that could go wrong because the script did nothing especial.

My ENTRYPOINT Script Was Super Basic

It does nothing except pass control back to whatever process is ran in your CMD instruction in your Dockerfile . That’s what exec «$@» does.

Setting #!/bin/sh is standard for setting up a shell environment. This is exactly what the official PostgreSQL image uses in its ENTRYPOINT script. It also uses set -e which tells your shell to halt on any error, and finally it also ends its script off with exec «$@» .

Using that logic, we can conclude without a doubt that there is nothing wrong with the above script in terms of syntax, yet it continues to throw that exec error.

Time to Investigate the Dockerfile

If the script isn’t the issue then it must be the ENTRYPOINT instruction or something to do with permissions on the script itself. Here’s the important bits of the Dockerfile :

If I’ve learned anything from working as a web developer for the last

20 years, it’s that you should never trust anything from the client.

In this context, that means I shouldn’t trust that the script is already executable when building the Docker image, so even though it adds an extra layer to the image, it’s important to chmod +x the script in the Dockerfile .

I was already doing that because I’ve been bit by that issue in the past.

The entrypoint location is also normal. That’s the absolute path to where it exists inside of the Docker image (it was COPY ‘d in a previous step not listed above).

Thought Process on Debugging This Further

At this point the Docker image builds but it fails to run due to the script. The next step is simple then, just comment out the ENTRYPOINT instruction and re-build it. Sure enough, the image builds and runs correctly.

With this new information we now have 5 facts:

  1. The script itself has no syntax errors
  2. The script is most definitely executable
  3. The Docker image builds, so the ENTRYPOINT has the correct file location
  4. A very popular Docker image (PostgreSQL) is using a nearly identical entrypoint
  5. The script is causing the error because it works without the ENTRYPOINT instruction

It’s unlikely there’s something wrong with the Docker daemon since the PostgreSQL image confirms it works, so I’m happy to rule that out considering I’ve ran the PostgreSQL image using the same Docker daemon version as I did with my entrypoint script.

Resolving the Error on IRC

At this point my eye was starting to twitch, and when that happens, that means it’s time to ask for external help, so I hopped on IRC.

I explained the situation and within a few minutes we uncovered the issue. I’m including the conversation here because I think the process is what’s important, not the solution:

Looking back, I like ada’s comment here about questioning me on what I meant by “works”. When it comes to real time communication, sometimes you don’t pick your words wisely. What I should have said was the Docker image builds successfully.

Anyways, let’s continue with the conversation:

Yep, I used the word “literally” wrong here because it had set -e and empty lines too! I just wanted to keep the script short on IRC (terrible idea btw).

Oh, now that’s a good idea. I didn’t even think about executing the script manually inside of the container. Thinking back, that was such an obvious thing to do, but guess what, this is how you learn.

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If an entrypoint script ever goes wrong in the future for me, or if one of the people taking my Docker course has a problem with an entrypoint script, you can be sure running it in the container directly will be near the top of my list of things to do / ask.

Ok, so, what’s line 3 of the script? Ah, it’s an empty new line. Side note, I didn’t include my exact script when asking for help which was a mistake because from their POV, line 3 was something different. Never try to be tricky when asking for help, but that’s a lesson for another day!

I have to admit, seeing foundypoint.sh there threw me off. What the heck does that have to do with anything. Looking at it now, the entire error is : not foundypoint.sh: 3: docker-entrypoint.sh:

That really says “not found” and point.sh is part of the docker-entrypoint.sh file name. Why it came out like that is above my pay grade, but at least it could in theory make some sense now.

Well, now it’s starting to add up. Guess who moved their code editor to be running in Windows the other month? Also, guess who recently moved to using VSCode? This guy!

Prior to that, I was running Sublime Text in a Linux driven VM for the last

5 years. CRLF vs LF line endings isn’t something I dealt with in over 5+ years.

Let’s continue with the story because it shows how to detect the issue and resolve it.

Things are starting to drift a little off topic, but ada guides us back to the main problem.

Bingo, that confirms the issue. Pesky CRLF line endings ( \r\n ) are in the file. The PostgreSQL entrypoint script has Unix style LF line endings ( \n ), but most code editors and GitHub don’t visibly show this, so it was invisible to the naked eye.

Special thanks to ada, programmerq and mgolisch for helping solve this mystery.

Now we know what we need to do, so let’s do it.

Configuring VSCode and WSL for LF Line Endings

Forcing Unix line endings in VSCode was very straight forward. Just drop this into your user settings: «files.eol»: «\n» . You could alternatively place that into a workspace setting for specific projects, in case you have projects that run on both Linux and Windows.

New files that you create should have a LF in the bottom right of the VSCode window instead of CRLF, but existing files that have CRLF line endings will continue to be CRLF.

Installing and Using dos2unix

From within WSL run sudo apt-get install dos2unix to install a utility that will automatically convert CRLF to LF.

Then just use it on a file by running dos2unix docker-entrypoint.sh or whatever file you’re converting. Done deal!

Now if you ran file docker-entrypoint.sh it would look like this instead: docker-entrypoint.sh: POSIX shell script, ASCII text executable . It no longer has with CRLF line terminators as we saw in the IRC chat log.

Of course, if you’ve been setting CRLF line endings for a project, you probably have a ton of files to convert and doing it 1 by 1 would be really tedious.

For that you can use the power of Unix pipes to recursively run dos2unix against a directory path of your choosing.

Recursively run dos2unix against all files in a path:

All you have to do is run find . -type f -print0 | xargs -0 dos2unix .

That will run it against the current directory. Replace . with a different path if you want.

If you’ve made it this far, now you know why the problem happened and how to fix it.

BONUS: Applying This Process to Other Problems

This is why I stand by the statement that breaking down problems is the #1 skill to have as a software developer. The solution was simple once the problem was understood and we got there by breaking things down and using a process of elimination.

And in case you’re wondering, I most definitely used the Rubber Duck debugging technique before I asked for help on IRC.

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Have you ever been bit by CRLF vs LF line endings? Let me know below!

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🛠️ Исправление ошибки «Exec format» при запуске скриптов командой run-parts

Решение ошибки «Exec format» при запуске скриптов командой run-parts

Чтобы запустить все скрипты в папке «Documents», я запустил:

Я получил следующее сообщение об ошибке:

Bourne shell, или совместимый шеллl:

Bash:

Perl:

Python 2.x:

Python 3.x:

Это то, что мы называем шебанг.

Теперь вернемся к теме.

Отредактируйте ваши скрипты, используя ваш любимый редактор:

Добавьте шебанг в начале скрипта:

Теперь вы можете без проблем запускать скрипты с помощью команды run-parts, используя команду run-parts.

Вы также можете использовать утилиту ShellCheck для поиска проблем в своих скриптах оболочки.

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Handle Exec Format Error In 8 Simple Points

The exec format error is a class of errors in the Unix-based operating systems that occurs when a user tries to run a binary file on its system originally intended to run on a different architecture. For example, when the user tries to execute a binary file originally compiled for the ARM (Advanced RISC Machine) on the x86 platform, an ‘exec format error’ is encountered. It is not in this particular case of arm and x86, but it could happen in any permutation of mismatched system architecture. In this article, we will look at this error in some detail and discuss some points that would help resolve this error.

What is Exec Format Error?

Different types of computer systems have different kinds of underlying architectures. Here, the term architecture means the circuitry and design of the CPU on how it handles and processes instructions and other computational tasks. System software and applications are compiled differently for a different architecture. Even the operating systems are designed specifically with a particular architecture in mind. There are two mainstream system architectures, The x86_64 and ARM. The x86_64 is mainly used in desktop computers and workstations, and ARM is used in mobile devices such as phones or tablets.

The x86_64 architecture can also be subdivided into 32bit and 64bits types. It represents the CPU’s memory handling capacity. Programs designed for ARM architecture can’t work on x86_64 systems and vice versa. But, the applications built for a 32bit machine can run on a 64bit. All combinations such as CPU architecture, Operating System build, and application design must come in to make everything work properly. And, If anything mismatches, an exec format error can show up.

Exec Format Error Linux

If you are trying to run incompatible programs or scripts in the Linux environment that doesn’t support the intended architecture, you are more likely to receive an exec format error. Linux itself comes in various forms and flavors in different distros. It is available on both x86_64 and ARM architecture. The most common cause of users receiving exec format errors is when 64bit programs are made to run on 32bit systems. If you are facing this error for a particular program due to an architectural issue, here are a few things that you could do.

  • Open the terminal emulator, enter the command uname -m, the m stands for machine. This command would output your system architecture. x86 -> 32 bit x86, x86_64 -> 64bit, arm64 -> ARM.
  • After knowing the correct architecture of your system, try to find the your program for that type of compatibility. The 32bit versions of the 64bit programs are ususally available on the internet.
  • If you are on a ARM system, then try to download the program through your default package manager as they usually have arm version of most of the programs availbale to install through official repositories.
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Exec format error macOS

macOS also throws an exec format error when you execute a program or script intended for a different architecture. This is usually the case with older binary programs that do not work well on modern operating systems. There are ways to execute older OS programs using the zsh shell, but you will have to build the executable yourself.

Download the program’s source code (if available ) you wish to run. Compile the program for your system using macOS’s make compiler. You would have to download make first, part of apple developer tools. It can be downloaded from http://developer.apple.com/.

Exec format error java

Java is a multipurpose, multiplatform object-oriented programming language that is a part of the whole JDK (java development kit). If you are trying to compile a java file on your system but receiving an exec format error instead, then chances are you have installed an incompatible version of the Java JDK on your system. Follow the given step to install the compatible version of JDK on your Linux machine as per the system architecture.

  • First check your system architecture using the uname -m command.
  • Now Open your Web browser.
  • Head to https://www.oracle.com/java/technologies/downloads/#jdk17-linux.
  • Now download the compatible version from the download options available.

You could also install the compatible version of JDK on your Linux installation using the default package manager of your distribution. Use the dpkg package manager on Debian-based and Pacman package manager on Arch-based Linux to install the correct implementation of java on your system.

Exec format error python

Python throws an exception in the form of exec format error. The python subprocess library provides the ability to run shell commands through the python interpreter. If any incompatible command or program is encountered during the python script, the python interpreter throws an OS exception. If you are running bash shell scripts through the subprocess library, keep the following points in mind to avoid exec format errors in python.

  • Add !/bin/sh in the top first line of your shell script file.
  • Use os library’s path method to open your .sh file, instead of opening it directly.
  • Make sure the script file has executable permission.

Exec format error docker

Docker is a software platform that provides operating system-level isolation environments called containers. The containers provide different separate development environments for specific projects or purposes. Users are reported to have been facing exec format errors while running the docker test command on their environment. This happens due to a missing statement in the script file. Run the following command to run the docker test without format error.

Exec format error raspberry pi

Raspberry pi is a small form-factor mini computer. It is a small computer that runs on low voltage power and has an ARM processor installed on it. The exec format error is frequently encountered in the raspberry pi as people often try to execute x86_64 on raspberry pi’s arm processor.

To avoid this error on the raspberry pi you have two potential options. You could either download the pi-compatible arm binary executables from their official repositories or download the program’s source code and compile it yourself for your intended system architecture. Luckily, Rasberry pi comes with its package manager apt (advance packaging tool) that can be used to install arm binaries on your raspberry pi.

How to execute arm binary files on Linux

Arm binary files are not directly executable on x86_64 Linux. The file command is used in Linux to check the file type in Linux. You can check the type and architecture of your file using it. If you want to run the arm files natively on Linux, you could download a package such as qemu, which could run the native arm files on the x86_64 machine. Follow the given steps to download and install the qemu to execute arm binaries on Arch.

  • Open the terminal. (ctrl + alt + t )
  • type sudo pacman -S qemu.
  • Enter the root password.
  • Enter Y when prompted and let the download finish.
  • After installation use the syntex qemu to execute the binary.

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