Problem to copy files with tmpfs

Help & Support
1

Hi guys, I have a question. Recently when I tested my package manager write in Crystal , I noticed if the files my package manager try to move are mounted in tmpfs like this:

tmpfs                   /tmp            tmpfs           rw,nosuid,noatime,nodev,mode=1777       0       0
tmpfs                   /var/tmp        tmpfs           rw,nosuid,noatime,nodev,mode=1777       0       0

It fail with the error that the file can’t be found . Why ?

2

Hard to tell, can you reduce the example to something we can run?

3

I try to.

This is the error I get:

[!] Failed to move /tmp/ism/builtsoftwares/KdeSoftwares-Main/Dolphin/23.8.0/usr/lib/libdolphinvcs.so.5 to /usr/lib/libdolphinvcs.so.5
[!] 
Error opening file with mode 'r': '/tmp/ism/builtsoftwares/KdeSoftwares-Main/Dolphin/23.8.0/usr/lib/libdolphinvcs.so.5': No such file or directory

And the function called from my software:

def runSystemCommand(command : String, path = Ism.settings.installByChroot ? "/" : Ism.settings.rootPath, environment = Hash(String, String).new, environmentFilePath = String.new) : Process::Status
            environmentCommand = String.new

            if environmentFilePath != ""
                environmentCommand = "source \"#{environmentFilePath}\" && "
            end

            environment.keys.each do |key|
                environmentCommand += " #{key}=\"#{environment[key]}\""
            end

            Ism.recordSystemCall(command, path, environment)

            if Ism.settings.installByChroot
                chrootCommand = <<-CODE
                #!/bin/bash
                cd #{path} && #{environmentCommand} #{command}
                CODE

                process = runChrootTasks(chrootCommand)
            else
                process = Process.run(  command,
                                        output: :inherit,
                                        error: :inherit,
                                        shell: true,
                                        chdir: (path == "" ? nil : path),
                                        env: environment)
            end

            return process
        end

def moveFile(path : String, newPath : String)
            requestedCommands = "mv #{path} #{newPath}"

            process = runSystemCommand(requestedCommands)

            if !process.success?
                Ism.notifyOfRunSystemCommandError(requestedCommands)
                Ism.exitProgram
            end
        end
4

Hi,

Your question seems more related to Linux systems than to Crystal, which might be why you’re not getting many replies. I wasn’t sure either, so I asked ChatGPT for some insight. I know it can be a bit annoying when people share AI-generated answers, so I hope you don’t mind. Here’s what it suggested:

It might be due to the chroot environment affecting access to /tmp or /var/tmp. Since chroot environments can’t access files outside their own directory structure, the files in /tmp might not be available inside the chroot. You might want to check if those directories are properly mounted within the chroot.

Hope this helps!

5

Trivia
It’s easy to download a Discourse discussion in Markdown text format. You can easily download the Markdown text for this page from the following URL.

https://forum.crystal-lang.org/raw/7185

2 Likes
6

@kojix2 That is an interesting bit of trivia. Might be interesting enough to be its own topic and not so buried.

7

It’s interesting, but actually this installation didn’t use the chroot mode. :sweat_smile: