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      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 // +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
      6 
      7 package os
      8 
      9 import (
     10 	"syscall"
     11 )
     12 
     13 // The only signal values guaranteed to be present in the os package
     14 // on all systems are Interrupt (send the process an interrupt) and
     15 // Kill (force the process to exit). Interrupt is not implemented on
     16 // Windows; using it with os.Process.Signal will return an error.
     17 var (
     18 	Interrupt Signal = syscall.SIGINT
     19 	Kill      Signal = syscall.SIGKILL
     20 )
     21 
     22 func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
     23 	// If there is no SysProcAttr (ie. no Chroot or changed
     24 	// UID/GID), double-check existence of the directory we want
     25 	// to chdir into. We can make the error clearer this way.
     26 	if attr != nil && attr.Sys == nil && attr.Dir != "" {
     27 		if _, err := Stat(attr.Dir); err != nil {
     28 			pe := err.(*PathError)
     29 			pe.Op = "chdir"
     30 			return nil, pe
     31 		}
     32 	}
     33 
     34 	sysattr := &syscall.ProcAttr{
     35 		Dir: attr.Dir,
     36 		Env: attr.Env,
     37 		Sys: attr.Sys,
     38 	}
     39 	if sysattr.Env == nil {
     40 		sysattr.Env = Environ()
     41 	}
     42 	for _, f := range attr.Files {
     43 		sysattr.Files = append(sysattr.Files, f.Fd())
     44 	}
     45 
     46 	pid, h, e := syscall.StartProcess(name, argv, sysattr)
     47 	if e != nil {
     48 		return nil, &PathError{"fork/exec", name, e}
     49 	}
     50 	return newProcess(pid, h), nil
     51 }
     52 
     53 func (p *Process) kill() error {
     54 	return p.Signal(Kill)
     55 }
     56 
     57 // ProcessState stores information about a process, as reported by Wait.
     58 type ProcessState struct {
     59 	pid    int                // The process's id.
     60 	status syscall.WaitStatus // System-dependent status info.
     61 	rusage *syscall.Rusage
     62 }
     63 
     64 // Pid returns the process id of the exited process.
     65 func (p *ProcessState) Pid() int {
     66 	return p.pid
     67 }
     68 
     69 func (p *ProcessState) exited() bool {
     70 	return p.status.Exited()
     71 }
     72 
     73 func (p *ProcessState) success() bool {
     74 	return p.status.ExitStatus() == 0
     75 }
     76 
     77 func (p *ProcessState) sys() interface{} {
     78 	return p.status
     79 }
     80 
     81 func (p *ProcessState) sysUsage() interface{} {
     82 	return p.rusage
     83 }
     84 
     85 func (p *ProcessState) String() string {
     86 	if p == nil {
     87 		return "<nil>"
     88 	}
     89 	status := p.Sys().(syscall.WaitStatus)
     90 	res := ""
     91 	switch {
     92 	case status.Exited():
     93 		res = "exit status " + itoa(status.ExitStatus())
     94 	case status.Signaled():
     95 		res = "signal: " + status.Signal().String()
     96 	case status.Stopped():
     97 		res = "stop signal: " + status.StopSignal().String()
     98 		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
     99 			res += " (trap " + itoa(status.TrapCause()) + ")"
    100 		}
    101 	case status.Continued():
    102 		res = "continued"
    103 	}
    104 	if status.CoreDump() {
    105 		res += " (core dumped)"
    106 	}
    107 	return res
    108 }
    109