os: could not iterate over named pipes on Windows

[Codehardt]

What version of Go are you using (go version)?

$ go version
go version go1.12.5 windows/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\mars9\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:\Users\mars9\go
set GOPROXY=
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\mars9\AppData\Local\Temp\go-build413446826=/tmp/go-build -gno-record-gcc-switches

What did you do?

I wanted to iterate over Windows' named pipes using os package:

	f, err := os.Open(`\\.\pipe`)
	if err != nil {
		log.Fatalf("Could not open pipe list: %s", err)
	}
	defer f.Close()
	stat, err := f.Stat()
	if err != nil {
		log.Fatalf("Could not get file stats: %s", err)
	}
	log.Printf("Is Directory: %t", stat.IsDir()) // output: false
	pipelist, err := f.Readdir(-1)
	if os.IsNotExist(err) {
		log.Print("Pipe list does not exist")
	} else if err != nil {
		log.Printf("Could not read pipe list: %s", err)
	}
	for _, pipe := range pipelist {
		log.Printf("Pipe found: %s", pipe.Name())
	}

What did you expect to see?

The same result as in Python:

for pipeName in os.listdir(r'\\.\pipe'):
    print("Pipe found: %s" % pipeName)

Pipe found: InitShutdown
Pipe found: lsass
Pipe found: ntsvcs
Pipe found: scerpc
...

What did you see instead?

Is Directory: false
Pipe list does not exist

[mdlayher]

It isn't clear to me if this is something that the standard library itself should handle, but I recently wrote some Go code to do just this if it helps: https://github.com/WireGuard/wgctrl-go/blob/master/internal/wguser/conn_windows.go#L196.

[mdlayher]

/cc @alexbrainman

[alexbrainman]

Or sure, maybe we could fix that code.

I don't have time to debug this, but, if someone is interested, maybe they could make code above work. Maybe FindFirstFile and FindNextFile could be used to read that directory.

Alex

[gopherbot]

Change https://golang.org/cl/181057 mentions this issue: os: treat the Windows named pipe root as a directory

[Codehardt]

Maybe FindFirstFile and FindNextFile could be used to read that directory.

Thanks, this solved my issue.

[mdlayher]

I've submitted a patch that makes this work with package os, but it needs a bit more work and it probably won't land until Go 1.14 at this point.

[iwdgo]

Documentation states explicitly that it is not possible to list pipes using Win 32 API. For the same reason, >dir \\.\\pipe\\ does not return anything but an error.

The same documentation suggests to use NtQueryDirectoryFile of library NtosKrnl which is unavailable in the syscall package.
For completeness, the Powershell instruction to list pipes on Windows is [System.IO.Directory]::GetFiles("\\.\\pipe\\"). The directory value is currently not supported by the files method which uses FindFirstFileW.

Adding the relevant call require seems more like a proposal.