github.com/rakyll/go@v0.0.0-20170216000551-64c02460d703/src/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 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  }