53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// We used to used this code for Darwin, but according to issue #19314
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// waitid returns if the process is stopped, even when using WEXITED.
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// +build linux
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package os
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import (
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"runtime"
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"syscall"
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"unsafe"
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)
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const _P_PID = 1
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// blockUntilWaitable attempts to block until a call to p.Wait will
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// succeed immediately, and reports whether it has done so.
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// It does not actually call p.Wait.
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func (p *Process) blockUntilWaitable() (bool, error) {
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// The waitid system call expects a pointer to a siginfo_t,
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// which is 128 bytes on all GNU/Linux systems.
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// On darwin/amd64, it requires 104 bytes.
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// We don't care about the values it returns.
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var siginfo [16]uint64
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psig := &siginfo[0]
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var r uintptr
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var e syscall.Errno
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for {
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r, _, e = syscall.Syscall6(syscall.SYS_WAITID, _P_PID, uintptr(p.Pid), uintptr(unsafe.Pointer(psig)), syscall.WEXITED|syscall.WNOWAIT, 0, 0)
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if e != syscall.EINTR {
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break
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}
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}
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runtime.KeepAlive(p)
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// Check r as well as e because syscall.Syscall6 currently
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// just returns errno, and the SIGCHLD signal handler may
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// change errno. See https://gcc.gnu.org/PR86331.
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if r != 0 && e != 0 {
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// waitid has been available since Linux 2.6.9, but
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// reportedly is not available in Ubuntu on Windows.
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// See issue 16610.
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if e == syscall.ENOSYS {
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return false, nil
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}
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return false, NewSyscallError("waitid", e)
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}
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return true, nil
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}
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