github.com/spotify/syslog-redirector-golang@v0.0.0-20140320174030-4859f03d829a/src/pkg/os/exec_posix.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 // +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 }