proposal: delete unix socket path on Dispose of bound Socket

[tmds]

aspnetcore repo has an open issue about unix socket not getting cleaned up on exit: dotnet/aspnetcore#14134.

The socket path of a unix domain socket acts as the address.
When the Socket gets disposed, we should make the address available by deleting the file.

With the current behavior, this program fails:

using System;
using System.Net.Sockets;

namespace console
{
    class Program
    {
        static void Main(string[] args)
        {
            var endpoint = new UnixDomainSocketEndPoint("/tmp/mysocket");
            var socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
            socket.Bind(endpoint);
            socket.Dispose();
            socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
            socket.Bind(endpoint);
        }
    }
}

$ dotnet run
Unhandled exception. System.Net.Sockets.SocketException (98): Address already in use
   at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 5111
   at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 738
   at System.Net.Sockets.Socket.Bind(EndPoint localEP) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 703
   at console.Program.Main(String[] args) in /tmp/console/Program.cs:line 15

Deleting the file is a visible change, so we should consider backwards compatibility.

Users are likely to have File.Delete already in their applications. Those calls will no-op (on ENOENT).

@wfurt @antonfirsov @stephentoub @dotnet/ncl what do you think?

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Issue Details

---

aspnetcore repo has an open issue about unix socket not getting cleaned up on exit: dotnet/aspnetcore#14134.

The socket path of a unix domain socket acts as the address.
When the Socket gets disposed, we should make the address available by deleting the file.

With the current behavior, this program fails:

using System;
using System.Net.Sockets;

namespace console
{
    class Program
    {
        static void Main(string[] args)
        {
            var endpoint = new UnixDomainSocketEndPoint("/tmp/mysocket");
            var socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
            socket.Bind(endpoint);
            socket.Dispose();
            socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
            socket.Bind(endpoint);
        }
    }
}

$ dotnet run
Unhandled exception. System.Net.Sockets.SocketException (98): Address already in use
   at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 5111
   at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 738
   at System.Net.Sockets.Socket.Bind(EndPoint localEP) in /_/src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs:line 703
   at console.Program.Main(String[] args) in /tmp/console/Program.cs:line 15

Deleting the file is a visible change, so we should consider backwards compatibility.

Users are likely to have File.Delete already in their applications. Those calls will no-op (on ENOENT).

@wfurt @antonfirsov @stephentoub @dotnet/ncl what do you think?

Author:	tmds
Assignees:	-
Labels:	area-System.Net.Sockets, untriaged
Milestone:	-

[karelz]

Sounds reasonable to me -- @antonfirsov @geoffkizer any thoughts?

[antonfirsov]

Sounds reasonable to me.

[karelz]

Triage: If there are no compat issue (with code manually deleting the file today), we are fine with this.