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os/exec: commands cannot start with standard file descriptors on Linux and Darwin #5695
Description
My CLI needs to run child commands and read their output. exec.Command("/bin/echo", "ok").Output() cannot do this with the current process implementation.
In dev at 93940cb6, Linux rejects ProcAttr.Files with files setting not implemented. os/exec supplies these files for standard input and output. Darwin returns not implemented. Process wait and exit status methods are also stubs. The command should return ok\n and a successful exit status.
This is a source check from 18 September 2026. #632 closed on 27 November 2024 and #4471 closed on 4 October 2025 after earlier process work. The remaining file descriptor and process state gaps need this follow-up.
#5634 contains the proposed implementation and tests. It closed on 17 September with a request for an issue. Darwin also needs #5612 and #5694 (PR #5636). Concurrent pipe and process creation needs #5692 (PR #5630). Interruptible pipe I/O and WaitDelay remain separate work.
Replacement draft PR #5699.
Activity
0pcom commentedon Oct 20, 2026
I have a branch that fixes this on Linux: dev...0magnet:tinygo:os-exec-linux. It starts the child from C with clone(CLONE_VM|CLONE_VFORK) and implements Wait, Kill and Signal. With dev,
exec.Command("echo", "hi").Output()fails with "files setting not implemented". With the branch it returns"hi\n", and a child that exits 3 reports ExitCode 3. Darwin is not covered, and I have no Mac to test on.yohimik commentedon Oct 22, 2026
Sorry, I created MR fixes long time ago as drafts, but wasn't able to change since was under police custody, thanks #5699