runtime: pipe syscall requires COMPAT_FREEBSD10 on FreeBSD 11 and 12

[dmgk]

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

$ go version
go version devel +0ae3b7cb74 Tue Nov 17 13:20:20 2020 +0000 freebsd/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
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/dmgk/.cache/go-build"
GOENV="/home/dmgk/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="freebsd"
GOINSECURE=""
GOMODCACHE="/home/dmgk/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="freebsd"
GOPATH="/home/dmgk/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/dmgk/opt/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/dmgk/opt/go/pkg/tool/freebsd_amd64"
GOVCS=""
GOVERSION="devel +0ae3b7cb74 Tue Nov 17 13:20:20 2020 +0000"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build433466628=/tmp/go-build -gno-record-gcc-switches"

What did you do?

$ ./all.bash

What did you expect to see?

All tests passing.

What did you see instead?

On FreeBSD 12-STABLE with kernel built only with COMPAT_FREEBSD11 as required by wiki [1]:

...
ok      regexp/syntax   1.706s
--- FAIL: TestSignalM (0.00s)
    crash_unix_test.go:325: function not implemented
--- FAIL: TestSetNonblock (0.00s)
    nbpipe_test.go:75: function not implemented
FAIL
FAIL    runtime 103.442s

pipe() became a wrapper around pipe2() in FreeBSD 11.0, and on FreeBSD 11 and 12 it requires a kernel built with COMPAT_FREEBSD10 [2]. It seems that either:

• wiki page [1] needs to be updated to mention that COMPAT_FREEBSD10 is required in addition to COMPAT_FREEBSD11, or
• given that FreeBSD 10 is EOL, runtime·pipe needs to be rewritten to be a wrapper around runtime·pipe2, similar to [3]

[1] https://github.com/golang/go/wiki/FreeBSD
[2] freebsd/freebsd-src@e4ef214
[3] https://github.com/golang/go/blob/master/src/runtime/sys_freebsd_arm64.s#L131

[tklauser]

Given that the final supported version for FreeBSD 10 is Go 1.12.4, FreeBSD 10 is EOL and the pipe2 syscall is available since FreeBSD 10.0 (according to https://www.freebsd.org/cgi/man.cgi?pipe(2)#IMPLEMENTATION_NOTES) let's implement runtime.pipe using the pipe2 syscall. This is already done for various other ports.

/cc @ianlancetaylor

[gopherbot]

Change https://golang.org/cl/270917 mentions this issue: runtime: use pipe2 syscall for pipe on freebsd