syscall: export Tc{get,set}pgrp for testing

Provide appropriate implementations of Tc{get,set}pgrp and export
these for use in the TestForeground* tests in exec_unix_test.go.
This avoids calling ioctl via syscall.Syscall on BSDs.

Fixes #59667
Updates #63900

Change-Id: Ice4dcedae1f0931c026bddf33043d3864a52d44e
Reviewed-on: https://go-review.googlesource.com/c/go/+/572155
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/syscall/export_linux_test.go b/src/syscall/export_linux_test.go
index 3aa877cfe3..9bcf73e771 100644
--- a/src/syscall/export_linux_test.go
+++ b/src/syscall/export_linux_test.go
@@ -4,6 +4,10 @@
 
 package syscall
 
+import (
+	"unsafe"
+)
+
 var (
 	RawSyscallNoError = rawSyscallNoError
 	ForceClone3       = &forceClone3
@@ -12,3 +16,19 @@ var (
 const (
 	Sys_GETEUID = sys_GETEUID
 )
+
+func Tcgetpgrp(fd int) (pgid int32, err error) {
+	_, _, errno := Syscall6(SYS_IOCTL, uintptr(fd), uintptr(TIOCGPGRP), uintptr(unsafe.Pointer(&pgid)), 0, 0, 0)
+	if errno != 0 {
+		return -1, errno
+	}
+	return pgid, nil
+}
+
+func Tcsetpgrp(fd int, pgid int32) (err error) {
+	_, _, errno := Syscall6(SYS_IOCTL, uintptr(fd), uintptr(TIOCSPGRP), uintptr(unsafe.Pointer(&pgid)), 0, 0, 0)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}