github.com/sbinet/go@v0.0.0-20160827155028-54d7de7dd62b/src/os/wait_wait6.go (about)

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build freebsd
     6  
     7  package os
     8  
     9  import (
    10  	"runtime"
    11  	"syscall"
    12  )
    13  
    14  const _P_PID = 0
    15  
    16  // blockUntilWaitable attempts to block until a call to p.Wait will
    17  // succeed immediately, and returns whether it has done so.
    18  // It does not actually call p.Wait.
    19  func (p *Process) blockUntilWaitable() (bool, error) {
    20  	var errno syscall.Errno
    21  	// The arguments on 32-bit FreeBSD look like the following:
    22  	// - freebsd32_wait6_args{ idtype, id1, id2, status, options, wrusage, info } or
    23  	// - freebsd32_wait6_args{ idtype, pad, id1, id2, status, options, wrusage, info } when PAD64_REQUIRED=1 on ARM, MIPS or PowerPC
    24  	if runtime.GOARCH == "386" {
    25  		_, _, errno = syscall.Syscall9(syscall.SYS_WAIT6, _P_PID, uintptr(p.Pid), 0, 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0, 0, 0)
    26  	} else if runtime.GOARCH == "arm" {
    27  		_, _, errno = syscall.Syscall9(syscall.SYS_WAIT6, _P_PID, 0, uintptr(p.Pid), 0, 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0, 0)
    28  	} else {
    29  		_, _, errno = syscall.Syscall6(syscall.SYS_WAIT6, _P_PID, uintptr(p.Pid), 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0)
    30  	}
    31  	runtime.KeepAlive(p)
    32  	if errno != 0 {
    33  		// The wait6 system call is supported only on FreeBSD
    34  		// 9.3 and above, so it may return an ENOSYS error.
    35  		if errno == syscall.ENOSYS {
    36  			return false, nil
    37  		}
    38  		return false, NewSyscallError("wait6", errno)
    39  	}
    40  	return true, nil
    41  }