FileStream does not work with P/Invoked file descriptor and SafeFileHandle #12783
Description
Steps to Reproduce
using System;
using System.IO;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
namespace linuxwriter
{
class Program
{
static void Main()
{
int fd;
try
{
fd = creat("file.txt", Convert.ToInt32("777", 8));
}
catch (Exception exception)
{
throw new Exception($"Error trying to create file: {exception.Message}");
}
if (fd == -1)
{
using (File.Create("file.txt"))
{
// File.Create() should have thrown an exception
}
File.Delete("file.txt");
throw new InvalidOperationException($"libc creat failed, but File.Create did not");
}
var sfh = new SafeFileHandle((IntPtr)fd, ownsHandle: true);
using (var stream = new FileStream(sfh, FileAccess.ReadWrite))
using (var writer = new StreamWriter(stream))
{
writer.WriteLine("Normally a binary file extracted from a zip");
}
}
[DllImport("libc", SetLastError = true)]
private static extern int creat(string pathname, int mode);
}
}Current Behavior
The file is created with the correct permissions, however, when attempting to use the file descriptor in a FileStream, it crashes with the following error and stack trace:
Unhandled Exception:
System.IO.IOException: Invalid handle to path "[Unknown]"
at System.IO.FileStream.Init (Microsoft.Win32.SafeHandles.SafeFileHandle safeHandle, System.IO.FileAccess access, System.Boolean ownsHandle, System.Int32 bufferSize, System.Boolean isAsync, System.Boolean isConsoleWrapper) [0x0007f] in <8f2c484307284b51944a1a13a14c0266>:0
at System.IO.FileStream..ctor (Microsoft.Win32.SafeHandles.SafeFileHandle handle, System.IO.FileAccess access, System.Int32 bufferSize, System.Boolean isAsync) [0x00011] in <8f2c484307284b51944a1a13a14c0266>:0
at System.IO.FileStream..ctor (Microsoft.Win32.SafeHandles.SafeFileHandle handle, System.IO.FileAccess access) [0x00000] in <8f2c484307284b51944a1a13a14c0266>:0
at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (Microsoft.Win32.SafeHandles.SafeFileHandle,System.IO.FileAccess)
at linuxwriter.Program.Main () [0x0007c] in <85036eb2b84e47d0aa546e0d393fb85b>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.IO.IOException: Invalid handle to path "[Unknown]"
at System.IO.FileStream.Init (Microsoft.Win32.SafeHandles.SafeFileHandle safeHandle, System.IO.FileAccess access, System.Boolean ownsHandle, System.Int32 bufferSize, System.Boolean isAsync, System.Boolean isConsoleWrapper) [0x0007f] in <8f2c484307284b51944a1a13a14c0266>:0
at System.IO.FileStream..ctor (Microsoft.Win32.SafeHandles.SafeFileHandle handle, System.IO.FileAccess access, System.Int32 bufferSize, System.Boolean isAsync) [0x00011] in <8f2c484307284b51944a1a13a14c0266>:0
at System.IO.FileStream..ctor (Microsoft.Win32.SafeHandles.SafeFileHandle handle, System.IO.FileAccess access) [0x00000] in <8f2c484307284b51944a1a13a14c0266>:0
at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (Microsoft.Win32.SafeHandles.SafeFileHandle,System.IO.FileAccess)
at linuxwriter.Program.Main () [0x0007c] in <85036eb2b84e47d0aa546e0d393fb85b>:0
Expected Behavior
Program should write to the file and close the file descriptor before exiting normally. FYI this code works as I expected with .NET Core
On which platforms did you notice this
[x] Linux
I haven't tried Mac, but this is not relevant for Windows as this code is P/Invoking a POSIX method to set permission bits that don't exist in filesystems on Windows.
Version Used:
Mono JIT compiler version 4.6.2 (Debian 4.6.2.7+dfsg-1ubuntu1)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: __thread
SIGSEGV: altstack
Notifications: epoll
Architecture: amd64
Disabled: none
Misc: softdebug
LLVM: supported, not enabled.
GC: sgen
Stacktrace
see above.