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 netbsd openbsd solaris windows
     6  
     7  package os
     8  
     9  import (
    10  	"runtime"
    11  	"syscall"
    12  )
    13  
    14  // The only signal values guaranteed to be present in the os package on all
    15  // systems are os.Interrupt (send the process an interrupt) and os.Kill (force
    16  // the process to exit). On Windows, sending os.Interrupt to a process with
    17  // os.Process.Signal is not implemented; it will return an error instead of
    18  // sending a signal.
    19  var (
    20  	Interrupt Signal = syscall.SIGINT
    21  	Kill      Signal = syscall.SIGKILL
    22  )
    23  
    24  func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
    25  	// If there is no SysProcAttr (ie. no Chroot or changed
    26  	// UID/GID), double-check existence of the directory we want
    27  	// to chdir into. We can make the error clearer this way.
    28  	if attr != nil && attr.Sys == nil && attr.Dir != "" {
    29  		if _, err := Stat(attr.Dir); err != nil {
    30  			pe := err.(*PathError)
    31  			pe.Op = "chdir"
    32  			return nil, pe
    33  		}
    34  	}
    35  
    36  	sysattr := &syscall.ProcAttr{
    37  		Dir: attr.Dir,
    38  		Env: attr.Env,
    39  		Sys: attr.Sys,
    40  	}
    41  	if sysattr.Env == nil {
    42  		sysattr.Env, err = environForSysProcAttr(sysattr.Sys)
    43  		if err != nil {
    44  			return nil, err
    45  		}
    46  	}
    47  	sysattr.Files = make([]uintptr, 0, len(attr.Files))
    48  	for _, f := range attr.Files {
    49  		sysattr.Files = append(sysattr.Files, f.Fd())
    50  	}
    51  
    52  	pid, h, e := syscall.StartProcess(name, argv, sysattr)
    53  
    54  	// Make sure we don't run the finalizers of attr.Files.
    55  	runtime.KeepAlive(attr)
    56  
    57  	if e != nil {
    58  		return nil, &PathError{"fork/exec", name, e}
    59  	}
    60  
    61  	return newProcess(pid, h), nil
    62  }
    63  
    64  func (p *Process) kill() error {
    65  	return p.Signal(Kill)
    66  }
    67  
    68  // ProcessState stores information about a process, as reported by Wait.
    69  type ProcessState struct {
    70  	pid    int                // The process's id.
    71  	status syscall.WaitStatus // System-dependent status info.
    72  	rusage *syscall.Rusage
    73  }
    74  
    75  // Pid returns the process id of the exited process.
    76  func (p *ProcessState) Pid() int {
    77  	return p.pid
    78  }
    79  
    80  func (p *ProcessState) exited() bool {
    81  	return p.status.Exited()
    82  }
    83  
    84  func (p *ProcessState) success() bool {
    85  	return p.status.ExitStatus() == 0
    86  }
    87  
    88  func (p *ProcessState) sys() interface{} {
    89  	return p.status
    90  }
    91  
    92  func (p *ProcessState) sysUsage() interface{} {
    93  	return p.rusage
    94  }
    95  
    96  func (p *ProcessState) String() string {
    97  	if p == nil {
    98  		return "<nil>"
    99  	}
   100  	status := p.Sys().(syscall.WaitStatus)
   101  	res := ""
   102  	switch {
   103  	case status.Exited():
   104  		res = "exit status " + itoa(status.ExitStatus())
   105  	case status.Signaled():
   106  		res = "signal: " + status.Signal().String()
   107  	case status.Stopped():
   108  		res = "stop signal: " + status.StopSignal().String()
   109  		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
   110  			res += " (trap " + itoa(status.TrapCause()) + ")"
   111  		}
   112  	case status.Continued():
   113  		res = "continued"
   114  	}
   115  	if status.CoreDump() {
   116  		res += " (core dumped)"
   117  	}
   118  	return res
   119  }
   120  
   121  // ExitCode returns the exit code of the exited process, or -1
   122  // if the process hasn't exited or was terminated by a signal.
   123  func (p *ProcessState) ExitCode() int {
   124  	// return -1 if the process hasn't started.
   125  	if p == nil {
   126  		return -1
   127  	}
   128  	return p.status.ExitStatus()
   129  }
   130
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