Home | History | Annotate | Download | only in os 
      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 on all systems
     14 // are Interrupt (send the process an interrupt) and Kill (force
     15 // the process to exit).
     16 var (
     17 	Interrupt Signal = syscall.SIGINT
     18 	Kill      Signal = syscall.SIGKILL
     19 )
     20 
     21 func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
     22 	// If there is no SysProcAttr (ie. no Chroot or changed
     23 	// UID/GID), double-check existence of the directory we want
     24 	// to chdir into. We can make the error clearer this way.
     25 	if attr != nil && attr.Sys == nil && attr.Dir != "" {
     26 		if _, err := Stat(attr.Dir); err != nil {
     27 			pe := err.(*PathError)
     28 			pe.Op = "chdir"
     29 			return nil, pe
     30 		}
     31 	}
     32 
     33 	sysattr := &syscall.ProcAttr{
     34 		Dir: attr.Dir,
     35 		Env: attr.Env,
     36 		Sys: attr.Sys,
     37 	}
     38 	if sysattr.Env == nil {
     39 		sysattr.Env = Environ()
     40 	}
     41 	for _, f := range attr.Files {
     42 		sysattr.Files = append(sysattr.Files, f.Fd())
     43 	}
     44 
     45 	pid, h, e := syscall.StartProcess(name, argv, sysattr)
     46 	if e != nil {
     47 		return nil, &PathError{"fork/exec", name, e}
     48 	}
     49 	return newProcess(pid, h), nil
     50 }
     51 
     52 func (p *Process) kill() error {
     53 	return p.Signal(Kill)
     54 }
     55 
     56 // ProcessState stores information about a process, as reported by Wait.
     57 type ProcessState struct {
     58 	pid    int                // The process's id.
     59 	status syscall.WaitStatus // System-dependent status info.
     60 	rusage *syscall.Rusage
     61 }
     62 
     63 // Pid returns the process id of the exited process.
     64 func (p *ProcessState) Pid() int {
     65 	return p.pid
     66 }
     67 
     68 func (p *ProcessState) exited() bool {
     69 	return p.status.Exited()
     70 }
     71 
     72 func (p *ProcessState) success() bool {
     73 	return p.status.ExitStatus() == 0
     74 }
     75 
     76 func (p *ProcessState) sys() interface{} {
     77 	return p.status
     78 }
     79 
     80 func (p *ProcessState) sysUsage() interface{} {
     81 	return p.rusage
     82 }
     83 
     84 func (p *ProcessState) String() string {
     85 	if p == nil {
     86 		return "<nil>"
     87 	}
     88 	status := p.Sys().(syscall.WaitStatus)
     89 	res := ""
     90 	switch {
     91 	case status.Exited():
     92 		res = "exit status " + itoa(status.ExitStatus())
     93 	case status.Signaled():
     94 		res = "signal: " + status.Signal().String()
     95 	case status.Stopped():
     96 		res = "stop signal: " + status.StopSignal().String()
     97 		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
     98 			res += " (trap " + itoa(status.TrapCause()) + ")"
     99 		}
    100 	case status.Continued():
    101 		res = "continued"
    102 	}
    103 	if status.CoreDump() {
    104 		res += " (core dumped)"
    105 	}
    106 	return res
    107 }
    108