syscall: use dup3 in forkAndExecInChild1 on all Linux platforms

The minimum required Linux kernel version for Go 1.18 will be changed to
2.6.32, see #45964. The dup3 syscall was added in 2.6.27, so the
fallback to use the dup2 syscall in forkAndExecInChild1 on some
platforms can be removed.

For #45964

Change-Id: I8e04d7b5b2488990a061a080ed64ea303ad048b8
Reviewed-on: https://go-review.googlesource.com/c/go/+/347350
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Tobias Klauser 2021-09-06 19:02:34 +02:00 committed by Tobias Klauser
parent 20a71c9a1d
commit a1938435d6
3 changed files with 3 additions and 36 deletions

View file

@ -448,13 +448,7 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
// so that pass 2 won't stomp on an fd it needs later.
if pipe < nextfd {
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(pipe), uintptr(nextfd), O_CLOEXEC)
if _SYS_dup != SYS_DUP3 && err1 == ENOSYS {
_, _, err1 = RawSyscall(_SYS_dup, uintptr(pipe), uintptr(nextfd), 0)
if err1 != 0 {
goto childerror
}
RawSyscall(fcntl64Syscall, uintptr(nextfd), F_SETFD, FD_CLOEXEC)
} else if err1 != 0 {
if err1 != 0 {
goto childerror
}
pipe = nextfd
@ -466,13 +460,7 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
nextfd++
}
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(fd[i]), uintptr(nextfd), O_CLOEXEC)
if _SYS_dup != SYS_DUP3 && err1 == ENOSYS {
_, _, err1 = RawSyscall(_SYS_dup, uintptr(fd[i]), uintptr(nextfd), 0)
if err1 != 0 {
goto childerror
}
RawSyscall(fcntl64Syscall, uintptr(nextfd), F_SETFD, FD_CLOEXEC)
} else if err1 != 0 {
if err1 != 0 {
goto childerror
}
fd[i] = nextfd
@ -497,7 +485,7 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
}
// The new fd is created NOT close-on-exec,
// which is exactly what we want.
_, _, err1 = RawSyscall(_SYS_dup, uintptr(fd[i]), uintptr(i), 0)
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(fd[i]), uintptr(i), 0)
if err1 != 0 {
goto childerror
}

View file

@ -1,11 +0,0 @@
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !android && (386 || amd64 || arm || mips || mipsle || mips64 || mips64le || ppc64 || ppc64le || s390x)
// +build !android
// +build 386 amd64 arm mips mipsle mips64 mips64le ppc64 ppc64le s390x
package syscall
const _SYS_dup = SYS_DUP2

View file

@ -1,10 +0,0 @@
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build android || arm64 || riscv64
// +build android arm64 riscv64
package syscall
const _SYS_dup = SYS_DUP3