github.com/4ad/go@v0.0.0-20161219182952-69a12818b605/src/os/exec.go (about)

     1  // Copyright 2009 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  package os
     6  
     7  import (
     8  	"runtime"
     9  	"sync"
    10  	"sync/atomic"
    11  	"syscall"
    12  )
    13  
    14  // Process stores the information about a process created by StartProcess.
    15  type Process struct {
    16  	Pid    int
    17  	handle uintptr      // handle is accessed atomically on Windows
    18  	isdone uint32       // process has been successfully waited on, non zero if true
    19  	sigMu  sync.RWMutex // avoid race between wait and signal
    20  }
    21  
    22  func newProcess(pid int, handle uintptr) *Process {
    23  	p := &Process{Pid: pid, handle: handle}
    24  	runtime.SetFinalizer(p, (*Process).Release)
    25  	return p
    26  }
    27  
    28  func (p *Process) setDone() {
    29  	atomic.StoreUint32(&p.isdone, 1)
    30  }
    31  
    32  func (p *Process) done() bool {
    33  	return atomic.LoadUint32(&p.isdone) > 0
    34  }
    35  
    36  // ProcAttr holds the attributes that will be applied to a new process
    37  // started by StartProcess.
    38  type ProcAttr struct {
    39  	// If Dir is non-empty, the child changes into the directory before
    40  	// creating the process.
    41  	Dir string
    42  	// If Env is non-nil, it gives the environment variables for the
    43  	// new process in the form returned by Environ.
    44  	// If it is nil, the result of Environ will be used.
    45  	Env []string
    46  	// Files specifies the open files inherited by the new process. The
    47  	// first three entries correspond to standard input, standard output, and
    48  	// standard error. An implementation may support additional entries,
    49  	// depending on the underlying operating system. A nil entry corresponds
    50  	// to that file being closed when the process starts.
    51  	Files []*File
    52  
    53  	// Operating system-specific process creation attributes.
    54  	// Note that setting this field means that your program
    55  	// may not execute properly or even compile on some
    56  	// operating systems.
    57  	Sys *syscall.SysProcAttr
    58  }
    59  
    60  // A Signal represents an operating system signal.
    61  // The usual underlying implementation is operating system-dependent:
    62  // on Unix it is syscall.Signal.
    63  type Signal interface {
    64  	String() string
    65  	Signal() // to distinguish from other Stringers
    66  }
    67  
    68  // Getpid returns the process id of the caller.
    69  func Getpid() int { return syscall.Getpid() }
    70  
    71  // Getppid returns the process id of the caller's parent.
    72  func Getppid() int { return syscall.Getppid() }