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System.IO.Directory.CreateTempSubdirectory(String prefix) fails with Success exception in wasi-wasm build #92336
Description
Description
Calling System.IO.Directory.CreateTempSubdirectory(String prefix) fails with an exception in a wasi-wasm build
Reproduction Steps
- .Net version 8.0.100-rc.1.23455.8
- tempDir.csproj
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net8.0</TargetFramework>
<RuntimeIdentifier>wasi-wasm</RuntimeIdentifier>
<OutputType>Exe</OutputType>
<PublishTrimmed>true</PublishTrimmed>
<WasmSingleFileBundle>true</WasmSingleFileBundle>
</PropertyGroup>
</Project>
- Program.cs
using System;
using System.IO;
using System.Text;
Console.WriteLine("Hello, Wasi Console!");
using (var writer = File.Create("/tmp/test.txt")) {
writer.Write(Encoding.UTF8.GetBytes("Hello World!"));
}
var dir = Directory.CreateTempSubdirectory();
Console.WriteLine("Created temp dir: " + dir.FullName);
- dotnet build
- create a tmp directory in the workspace directory
- wasmtime 12.0.2
- run
wasmtime run --mapdir /::. --env TMPDIR=/tmp obj/Debug/net8.0/wasi-wasm/wasm/for-build/tempDir.wasm
Expected behavior
Creating the temp directory works
Actual behavior
System.IO.IOException: Success
at Interop.ThrowExceptionForIoErrno(ErrorInfo errorInfo, String path, Boolean isDirError)
at Interop.ThrowIOExceptionForLastError()
at System.IO.Directory.CreateTempSubdirectoryCore(String prefix)
at System.IO.Directory.CreateTempSubdirectory(String prefix)
at Program.<Main>$(String[] args)
The write to the file happened successful.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
No response
Activity
dbaeumer commentedon Sep 20, 2023
I can create a directory as well using the following code
pavelsavara commentedon Sep 20, 2023
Could be related #81210 and WebAssembly/wasi-libc#414
dbaeumer commentedon Sep 20, 2023
@pavelsavara I executed the WASM file on the VS Code WASI host implementation which offers nice tracing of host calls. The
Directory.CreateTempSubdirectory()call doesn't result in any host calls, so I guess this fails inside some C# code and is falsely reported as a exception with anerrno. There aren't anyfd_readdircalls either before.What I did notice as well is that the wasm code does tons of
clock_time_get(id: monotonic, precision: 1)calls.pavelsavara commentedon Sep 20, 2023
See
runtime/src/native/libs/System.Native/pal_io.c
Lines 850 to 852 in 32c3355
https://github.com/WebAssembly/wasi-libc/blob/ce2f157d46e04f323edf93f02c8f60069d88df96/libc-top-half/musl/include/stdlib.h#L118-L122
dbaeumer commentedon Sep 20, 2023
Any reason why we couldn't implement that in C# for WASI. I can understand why we can't use libc since they hardcode
/tmpbut Python on wasm-wasi has support for this since they come with their ownmkdtempimplementation.pavelsavara commentedon Sep 20, 2023
That's what #81210 wants I think.
It would be also good to do that for emscripten build.
Because the idea of generating randomness out of timer + checking if there is file system conflict is very ugly.
We had issues with that already because of the granularity of browser timer used.
https://github.com/emscripten-core/emscripten/blob/813a727fa77b3596c75a6d62b2fdb87365f9d75a/system/lib/libc/musl/src/temp/mkdtemp.c#L16-L19
https://github.com/emscripten-core/emscripten/blob/813a727fa77b3596c75a6d62b2fdb87365f9d75a/system/lib/libc/musl/src/temp/__randname.c#L13-L14
PR welcome.
adamsitnik commentedon Sep 22, 2023
It reminds me of
pavelsavara commentedon Sep 22, 2023
SetLastErrorFTW ? 😎ilonatommy commentedon Jul 9, 2024
blocked by WebAssembly/wasi-libc#229