exec_posix.go

Documentation: 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 aix darwin dragonfly freebsd js,wasm 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 on all
    14  // systems are os.Interrupt (send the process an interrupt) and os.Kill (force
    15  // the process to exit). On Windows, sending os.Interrupt to a process with
    16  // os.Process.Signal is not implemented; it will return an error instead of
    17  // sending a signal.
    18  var (
    19  	Interrupt Signal = syscall.SIGINT
    20  	Kill      Signal = syscall.SIGKILL
    21  )
    22  
    23  func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
    24  	// If there is no SysProcAttr (ie. no Chroot or changed
    25  	// UID/GID), double-check existence of the directory we want
    26  	// to chdir into. We can make the error clearer this way.
    27  	if attr != nil && attr.Sys == nil && attr.Dir != "" {
    28  		if _, err := Stat(attr.Dir); err != nil {
    29  			pe := err.(*PathError)
    30  			pe.Op = "chdir"
    31  			return nil, pe
    32  		}
    33  	}
    34  
    35  	sysattr := &syscall.ProcAttr{
    36  		Dir: attr.Dir,
    37  		Env: attr.Env,
    38  		Sys: attr.Sys,
    39  	}
    40  	if sysattr.Env == nil {
    41  		sysattr.Env = Environ()
    42  	}
    43  	for _, f := range attr.Files {
    44  		sysattr.Files = append(sysattr.Files, f.Fd())
    45  	}
    46  
    47  	pid, h, e := syscall.StartProcess(name, argv, sysattr)
    48  	if e != nil {
    49  		return nil, &PathError{"fork/exec", name, e}
    50  	}
    51  	return newProcess(pid, h), nil
    52  }
    53  
    54  func (p *Process) kill() error {
    55  	return p.Signal(Kill)
    56  }
    57  
    58  // ProcessState stores information about a process, as reported by Wait.
    59  type ProcessState struct {
    60  	pid    int                // The process's id.
    61  	status syscall.WaitStatus // System-dependent status info.
    62  	rusage *syscall.Rusage
    63  }
    64  
    65  // Pid returns the process id of the exited process.
    66  func (p *ProcessState) Pid() int {
    67  	return p.pid
    68  }
    69  
    70  func (p *ProcessState) exited() bool {
    71  	return p.status.Exited()
    72  }
    73  
    74  func (p *ProcessState) success() bool {
    75  	return p.status.ExitStatus() == 0
    76  }
    77  
    78  func (p *ProcessState) sys() interface{} {
    79  	return p.status
    80  }
    81  
    82  func (p *ProcessState) sysUsage() interface{} {
    83  	return p.rusage
    84  }
    85  
    86  func (p *ProcessState) String() string {
    87  	if p == nil {
    88  		return "<nil>"
    89  	}
    90  	status := p.Sys().(syscall.WaitStatus)
    91  	res := ""
    92  	switch {
    93  	case status.Exited():
    94  		res = "exit status " + itoa(status.ExitStatus())
    95  	case status.Signaled():
    96  		res = "signal: " + status.Signal().String()
    97  	case status.Stopped():
    98  		res = "stop signal: " + status.StopSignal().String()
    99  		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
   100  			res += " (trap " + itoa(status.TrapCause()) + ")"
   101  		}
   102  	case status.Continued():
   103  		res = "continued"
   104  	}
   105  	if status.CoreDump() {
   106  		res += " (core dumped)"
   107  	}
   108  	return res
   109  }
   110  
   111  // ExitCode returns the exit code of the exited process, or -1
   112  // if the process hasn't exited or was terminated by a signal.
   113  func (p *ProcessState) ExitCode() int {
   114  	// return -1 if the process hasn't started.
   115  	if p == nil {
   116  		return -1
   117  	}
   118  	return p.status.ExitStatus()
   119  }
   120
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