libgo/go/os/exec_posix.go

   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 netbsd openbsd 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 // Convert i to decimal string.
  85 func itod(i int) string {
  86         if i == 0 {
  87                 return "0"
  88         }
  89
  90         u := uint64(i)
  91         if i < 0 {
  92                 u = -u
  93         }
  94
  95         // Assemble decimal in reverse order.
  96         var b [32]byte
  97         bp := len(b)
  98         for ; u > 0; u /= 10 {
  99                 bp--
 100                 b[bp] = byte(u%10) + '0'
 101         }
 102
 103         if i < 0 {
 104                 bp--
 105                 b[bp] = '-'
 106         }
 107
 108         return string(b[bp:])
 109 }
 110
 111 func (p *ProcessState) String() string {
 112         if p == nil {
 113                 return "<nil>"
 114         }
 115         status := p.Sys().(syscall.WaitStatus)
 116         res := ""
 117         switch {
 118         case status.Exited():
 119                 res = "exit status " + itod(status.ExitStatus())
 120         case status.Signaled():
 121                 res = "signal: " + status.Signal().String()
 122         case status.Stopped():
 123                 res = "stop signal: " + status.StopSignal().String()
 124                 if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
 125                         res += " (trap " + itod(status.TrapCause()) + ")"
 126                 }
 127         case status.Continued():
 128                 res = "continued"
 129         }
 130         if status.CoreDump() {
 131                 res += " (core dumped)"
 132         }
 133         return res
 134 }