Exception not thrown for ZipFile inside Blazor-Server Service

[BuchholzTim]

Description

Creating an archive of a folder (in blazor), which contains a named pipe in DotNet 6.0 via the ZipFile Class causes the program to block indefinitely long, without any kind of exception thrown.

1. Create a Named Pipe in a Linux distribution with mkfifo (for me this happened while running my dotnet application inside a docker conatiner)
2. Try to compress the directory containing the named pipe with ZipFile.CreateFromDirectory inside a Blazor-Server Service

Configuration

• .NETCore 6.0.0
• Hosted Blazor Webassembly (dotnet new blazorwasm -ho)

Other information

An Exception is thrown when I try to ZIP the same directory inside a simple Dotnet Console Application.

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Issue Details

---

Description

Creating an archive of a folder (in blazor), which contains a named pipe in DotNet 6.0 via the ZipFile Class causes the program to block indefinitely long, without any kind of exception thrown.

1. Create a Named Pipe in a Linux distribution with mkfifo (for me this happened while running my dotnet application inside a docker conatiner)
2. Try to compress the directory containing the named pipe with ZipFile.CreateFromDirectory inside a Blazor-Server Service

Configuration

• .NETCore 6.0.0
• Hosted Blazor Webassembly (dotnet new blazorwasm -ho)

Other information

An Exception is thrown when I try to ZIP the same directory inside a simple Dotnet Console Application.

Author:	BuchholzTim
Assignees:	-
Labels:	area-System.IO.Compression, untriaged
Milestone:	-

[adamsitnik]

Hi @BuchholzTim

Are you sure that you are using mkfifo correctly? It's quite easy to get blocked using it.

Accodring to mkfifo man page:

Opening a FIFO for reading normally blocks
until some other process opens the same FIFO for writing, and
vice versa.

Moreover, the reading is finished when writer closes the file descriptor.

[adamsitnik]

An Exception is thrown when I try to ZIP the same directory inside a simple Dotnet Console Application.

I've tried to repro that, but I've failed. Here is the code that I've used:

public async Task CanZipNamedPipe()
{
    string destPath = Path.Combine(TestDirectory, "dest.zip");

    string subFolderPath = Path.Combine(TestDirectory, "subfolder");
    string fifoPath = Path.Combine(subFolderPath, "namedPipe");
    Directory.CreateDirectory(subFolderPath); // mandatory before calling mkfifo
    Assert.Equal(0, mkfifo(fifoPath, 438 /* 666 in octal */));

    byte[] contentBytes = { 1, 2, 3, 4, 5 };

    await Task.WhenAll(
        Task.Run(() =>
        {
            using FileStream fs = new (fifoPath, FileMode.Open, FileAccess.Write, FileShare.Read);
            foreach (byte content in contentBytes)
            {
                fs.WriteByte(content);
            }
        }),
        Task.Run(() =>
        {
            ZipFile.CreateFromDirectory(subFolderPath, destPath);

            using ZipArchive zippedFolder = ZipFile.OpenRead(destPath);
            using Stream unzippedPipe = zippedFolder.Entries.Single().Open();

            byte[] readBytes = new byte[contentBytes.Length];
            Assert.Equal(contentBytes.Length, unzippedPipe.Read(readBytes));
            Assert.Equal<byte>(contentBytes, readBytes);
            Assert.Equal(0, unzippedPipe.Read(readBytes)); // EOF
        }));
}

[DllImport("libc", SetLastError = true)]
private static extern int mkfifo(string path, int mode);

@BuchholzTim Could you please share more details (repro, stack trace)?

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