Stream: git-wasmtime

Topic: wasmtime / issue #9174 Native Golang build + file access ...

Wasmtime GitHub notifications bot (Aug 27 2024 at 18:35):

brendandburns added the bug label to Issue #9174.

Wasmtime GitHub notifications bot (Aug 27 2024 at 18:35):

brendandburns opened issue #9174:

Test Case

package main

import (
    "fmt"
    "log"
    "os"
)

func main() {
    stat, err := os.Stat("./")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", stat.Name())

    entries, err := os.ReadDir("./")
    if err != nil {
        log.Fatal(err)
    }
    for _, entry := range entries {
        fmt.Printf("\t%s\n", entry.Name())
    }

    file, err := os.Open("main.go")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", file.Name())

    if err := os.WriteFile("test.txt", []byte("This is test data"), 0x777); err != nil {
        log.Fatal(err)
    }
}

Steps to Reproduce

• GOOS=wasip1 GOARCH=wasm go build -o main.wasm main.go
• wasmtime --dir .::. main.wasm

Expected Results

Generated code should be able to open files mapped in via --dir

Actual Results

``
...
2024/08/27 18:27:51 open main.go: Bad file number

### Versions and Environment

Wasmtime version or commit: 24.0

Operating system: Linux

Architecture: x86_64

### Extra Info

I don't know if this is a Golang or a wasmtime issue.
~~~

Wasmtime GitHub notifications bot (Aug 27 2024 at 18:35):

brendandburns edited issue #9174:

Test Case

package main

import (
    "fmt"
    "log"
    "os"
)

func main() {
    stat, err := os.Stat("./")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", stat.Name())

    entries, err := os.ReadDir("./")
    if err != nil {
        log.Fatal(err)
    }
    for _, entry := range entries {
        fmt.Printf("\t%s\n", entry.Name())
    }

    file, err := os.Open("main.go")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", file.Name())

    if err := os.WriteFile("test.txt", []byte("This is test data"), 0x777); err != nil {
        log.Fatal(err)
    }
}

Steps to Reproduce

• GOOS=wasip1 GOARCH=wasm go build -o main.wasm main.go
• wasmtime --dir .::. main.wasm

Expected Results

Generated code should be able to open files mapped in via --dir

Actual Results

...
2024/08/27 18:27:51 open main.go: Bad file number

Versions and Environment

Wasmtime version or commit: 24.0

Operating system: Linux

Architecture: x86_64

Extra Info

I don't know if this is a Golang or a wasmtime issue.

Wasmtime GitHub notifications bot (Aug 27 2024 at 19:06):

bjorn3 commented on issue #9174:

Can you try running with WASMTIME_LOG=wasmtime_wasi=trace? That should show all wasi syscalls executed by the wasm module with all arguments and error results.

Wasmtime GitHub notifications bot (Aug 28 2024 at 16:23):

primoly commented on issue #9174:

The issue does not occur if you use wasmtime --dir .::/ main.wasm (Note the .::/ instead of .::.)

I think Go always adds a / at the beginning of the path. Changing to os.Open("./main.go") does not resolve the issue.

Rust’s std::fs::File::open works with both absolute and relative paths as it uses wasi-libc which does the mapping automatically so I guess this is an issue with the Go bindings to Wasi.

Wasmtime GitHub notifications bot (Aug 28 2024 at 18:13):

brendandburns closed issue #9174:

Test Case

package main

import (
    "fmt"
    "log"
    "os"
)

func main() {
    stat, err := os.Stat("./")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", stat.Name())

    entries, err := os.ReadDir("./")
    if err != nil {
        log.Fatal(err)
    }
    for _, entry := range entries {
        fmt.Printf("\t%s\n", entry.Name())
    }

    file, err := os.Open("main.go")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s\n", file.Name())

    if err := os.WriteFile("test.txt", []byte("This is test data"), 0x777); err != nil {
        log.Fatal(err)
    }
}

Steps to Reproduce

• GOOS=wasip1 GOARCH=wasm go build -o main.wasm main.go
• wasmtime --dir .::. main.wasm

Expected Results

Generated code should be able to open files mapped in via --dir

Actual Results

...
2024/08/27 18:27:51 open main.go: Bad file number

Versions and Environment

Wasmtime version or commit: 24.0

Operating system: Linux

Architecture: x86_64

Extra Info

I don't know if this is a Golang or a wasmtime issue.

Wasmtime GitHub notifications bot (Aug 28 2024 at 18:13):

brendandburns commented on issue #9174:

Changing --dir .::.. to --dir .::/ fixes things.

I agree that this feels like a bug in the Go + Wasi bindings, I'll look into that codebase.

Closing this issue here.

Wasmtime GitHub notifications bot (Aug 28 2024 at 18:13):

brendandburns edited a comment on issue #9174:

Changing --dir .::. to --dir .::/ fixes things.

I agree that this feels like a bug in the Go + Wasi bindings, I'll look into that codebase.

Closing this issue here.

Last updated: Oct 23 2024 at 20:03 UTC