syscall: exec.Cmd.Run, os.Pipe broken on linux 2.6.23 / arm #30549
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ALTree
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ALTree
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Assuming your analysis is correct, it seems there are two paths forward: either we fix |
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(OT but I’d love to see a blog post on running Go programs on Kindles. I’ve always meant to do that and never got around to it. A mini tutorial would be awesome.) |
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@ALTree AFAIR the minimum kernel version for linux/arm is 2.6.27. The reference to 2.6.23 is for linux on intel platforms. |
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The problem is clear enough: your kernel doesn't support Another consideration is Android O, which has a seccomp filter. If I'm reading https://android.googlesource.com/platform/bionic/+/master/libc/SYSCALLS.TXT correctly, Android O systems only permit But we can try |
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Change https://golang.org/cl/165217 mentions this issue: |
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Change https://golang.org/cl/165297 mentions this issue: |
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@josharian You wrote:
Try reading the Readme of his project, it’s pretty much what you asked for. |
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@ianlancetaylor Thanks for fixing this! @josharian No blog of this stuff yet, but as zephyr mentioned I have a bit of a hacking log here. |
Follow CL 165217 which did this for package syscall. Android O seems to require Pipe to call the pipe2 system call. But kernel version 2.6.23 only supports pipe, not pipe2. So try pipe2 first, then fall back to pipe. Updates golang/go#30549 Change-Id: Icf21433fa046ff137c0265fa96410229def482f7 Reviewed-on: https://go-review.googlesource.com/c/sys/+/165297 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
What did you do?
I'm writing some software for old ereaders, specifically older Kindles. I've been cross compiling on macOS 10.14 using
env GOOS=linux GOARCH=arm GOARM=6 go .... This work great, except that I can't useexec.Commandor any other code that relies onsyscall.Pipeas it returns afunction not implementederror.I'm using
exec.Cmd.Run()like so:However, this more minimal case will demonstrate the issue I am seeing:
When I run this code on the device, it fails with:
I think the cause is that
syscall.Pipeis implemented usingpipe2on linux/arm:It looks like pipe2 is only supported by linux 2.6.27. I'm on 2.6.23, which is listed as the minimum in the Go system requirements.
Interestingly, there is a comment to that recognizes this situation in src/os/pipe_linux.go:
The workaround above isn't going to make a difference, though, since
syscall.Pipestill callspipe2.You can see that there are 2
pipe2syscalls when the program is run usingstrace(the full output is included below):The same issue seems to be present in the
syspackage as well.What did you expect to see?
No error.
What did you see instead?
Solution
I have been working around this by modifying my Go distribution like so:
Changing the definition of
syscall.Pipeto the following insrc/syscall/linux_arm.go:And then adding the following to
src/syscall/zsyscall_linux_arm.go(which I realize is normally autogenerated):I can see this OS not being officially supported as it is rather out of date, but that would be a bit of a shame since Go's cross compiling makes developing for this kind of older hardware a really nice experience.
System details
Device info:
Here is the output of running the executable with
straceshowing the failed attempt to use thepipe2syscall:The text was updated successfully, but these errors were encountered: