"No such file or directory" issue when trying to run C# program using Dotnet

[subhtak]

isolate --cg -p --chdir=CSHARP11_BASIC/src --open-files=1024 -E HOME=tmp --box-id=555 --run -- /usr/local/dotnet-sdk/dotnet run

MSBUILD : error MSB1025: An internal failure occurred while running MSBuild.
System.IO.IOException: No such file or directory

Microsoft.Build.CommandLine.MSBuildApp.Execute(String[] commandLine)
Unhandled exception: System.IO.IOException: No such file or directory
   at Interop.Sys.TryGetUserNameFromPasswd(UInt32 uid, Byte* buf, Int32 bufLen, String& username)
   at Interop.Sys.GetUserNameFromPasswd(UInt32 uid)
   at System.Environment.get_UserName()

Thank you in advance

[gollux]

dotnet is very peculiar in many senses and it is hard to get it running within a sandbox. I tried that a few months ago and the results is issue 1243 in CMS repository, which documents all the roadblocks I encountered.

In this case, you need to provide /etc/passwd with entries for the UIDs used by the sandbox.

[subhtak]

@gollux thanks for the reply. Attached is the /etc/passwd. I don't have much idea how to add user account specific to this usecase. Pls suggest.
passwd.txt

[gollux]

Look at Isolate's configuration file and find the UID range used for sandboxes. Add corresponding entries to passwd.

[subhtak]

Hey @gollux

I am not very clear with how to make the entry there in etc/passwd as the created user info is not known. Following fields are required separated by colon (:)

1. Encrypted Password
2. UID number
3. Default GID number
4. user information: full name, office, phone, …
5. Home directory
6. Login shell

I am not able to find out the process id nor the uid/gid when the isolate command is run.
This is the range I have in config:

Block of UIDs and GIDs reserved for sandboxes
first_uid = 60000
first_gid = 60000
num_boxes = 50000

Please help @gollux

[gollux]

You do not need a process ID, just the user ID. You can determine it by running /usr/bin/id -a in the sandbox, or compute it as a sum of first_uid from the configuration with the ID of the sandbox you are starting (if you do not specify an explicit ID, it defaults to 0).

[subhtak]

Thanks @gollux. After making the required entry in the /etc/passwd, the issue is resolved and dotnet commands are working inside isolate. But everytime making an entry in the /etc/passwd for every code execution is not great idea. I hope we can find a more optimal solution for this.

[gollux]

Just add the required users to /etc/passwd in the host system.