write failed error running in wasmtime

[leonardas103]

This is somewhat related to: Issue

In wasmtime writing to file I get the following error:

thread 'main' panicked at 'write failed: Os { code: 76, kind: Other, message: "Capabilities insufficient" }', src/libcore/result.rs:1084:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
error: failed to process main module `demo.wasm`
    caused by: Instantiation error: Trap occurred while invoking start function: wasm trap: unreachable, source location: @3adc6

I do include the file directory properly: wasmtime --dir=. demo.wasm '{"a":"txt","b": 1}'
While with wasmer I do not get this error.
Note: See the code linked in the wasmer issue. Also, this error is the same without the append flag.

[kubkon]

Hey @leonardas103! Thanks for submitting the issue. It looks to me like perhaps an issue with our WASI implementation. Could you do me a favour and re-run your binary with logs for wasi-common enabled like so:

RUST_LOG=wasi_common=trace wasmtime -d --dir=. demo.wasm '{"a": "txt", "b": 1}'

This will effectively enable trace level logs for our WASI syscalls implementation.

[bjorn3]

I think this should be closed. It has been a year without response and in the mean time the wasi implementation has been completely rewritten.

[peterhuene]

Agreed. @leonardas103 if you're able to reproduce this with a recent Wasmtime build, please let us know.

[leonardas103]

Now when I run my old wasm file with wasmtime (0.25.0) I get:

Error: failed to run main module `demo_old.wasm`

Caused by:
    0: failed to instantiate "demo_old.wasm"
    1: command export '__rustc_debug_gdb_scripts_section__' is not a function

I recompiled the code with the latest rust (1.50.0) and the program works as intended, however in the trace there was an error:

 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > wiggle abi; module="wasi_snapshot_preview1" function="environ_sizes_get"
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > result=Ok((0, 0)) 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > wiggle abi; module="wasi_snapshot_preview1" function="fd_prestat_get"
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > fd=Fd(3) 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > result=Ok(Dir(PrestatDir { pr_name_len: 1 })) 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > wiggle abi; module="wasi_snapshot_preview1" function="fd_prestat_dir_name"
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > fd=Fd(3) path=*guest 0x110010 path_len=1 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > result=Ok(()) 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > wiggle abi; module="wasi_snapshot_preview1" function="fd_prestat_get"
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > fd=Fd(4) 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > result=Err(Badf: Bad file descriptor) 
 DEBUG wasi_common::snapshots::preview_1                         > **Error: Badf: Bad file descriptor** 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > wiggle abi; module="wasi_snapshot_preview1" function="fd_write"
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > fd=Fd(1) iovs=*guest 0xffcb0/1 
 TRACE wasi_common::snapshots::preview_1::wasi_snapshot_preview1 > result=Ok(43) 

But this is probably nothing. The program writes to file as intended.