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  	"internal/syscall/execenv"
    11  	"runtime"
    12  	"syscall"
    13  )
    14  
    15  // The only signal values guaranteed to be present in the os package on all
    16  // systems are os.Interrupt (send the process an interrupt) and os.Kill (force
    17  // the process to exit). On Windows, sending os.Interrupt to a process with
    18  // os.Process.Signal is not implemented; it will return an error instead of
    19  // sending a signal.
    20  var (
    21  	Interrupt Signal = syscall.SIGINT
    22  	Kill      Signal = syscall.SIGKILL
    23  )
    24  
    25  func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
    26  	// If there is no SysProcAttr (ie. no Chroot or changed
    27  	// UID/GID), double-check existence of the directory we want
    28  	// to chdir into. We can make the error clearer this way.
    29  	if attr != nil && attr.Sys == nil && attr.Dir != "" {
    30  		if _, err := Stat(attr.Dir); err != nil {
    31  			pe := err.(*PathError)
    32  			pe.Op = "chdir"
    33  			return nil, pe
    34  		}
    35  	}
    36  
    37  	sysattr := &syscall.ProcAttr{
    38  		Dir: attr.Dir,
    39  		Env: attr.Env,
    40  		Sys: attr.Sys,
    41  	}
    42  	if sysattr.Env == nil {
    43  		sysattr.Env, err = execenv.Default(sysattr.Sys)
    44  		if err != nil {
    45  			return nil, err
    46  		}
    47  	}
    48  	sysattr.Files = make([]uintptr, 0, len(attr.Files))
    49  	for _, f := range attr.Files {
    50  		sysattr.Files = append(sysattr.Files, f.Fd())
    51  	}
    52  
    53  	pid, h, e := syscall.StartProcess(name, argv, sysattr)
    54  
    55  	// Make sure we don't run the finalizers of attr.Files.
    56  	runtime.KeepAlive(attr)
    57  
    58  	if e != nil {
    59  		return nil, &PathError{"fork/exec", name, e}
    60  	}
    61  
    62  	return newProcess(pid, h), nil
    63  }
    64  
    65  func (p *Process) kill() error {
    66  	return p.Signal(Kill)
    67  }
    68  
    69  // ProcessState stores information about a process, as reported by Wait.
    70  type ProcessState struct {
    71  	pid    int                // The process's id.
    72  	status syscall.WaitStatus // System-dependent status info.
    73  	rusage *syscall.Rusage
    74  }
    75  
    76  // Pid returns the process id of the exited process.
    77  func (p *ProcessState) Pid() int {
    78  	return p.pid
    79  }
    80  
    81  func (p *ProcessState) exited() bool {
    82  	return p.status.Exited()
    83  }
    84  
    85  func (p *ProcessState) success() bool {
    86  	return p.status.ExitStatus() == 0
    87  }
    88  
    89  func (p *ProcessState) sys() interface{} {
    90  	return p.status
    91  }
    92  
    93  func (p *ProcessState) sysUsage() interface{} {
    94  	return p.rusage
    95  }
    96  
    97  func (p *ProcessState) String() string {
    98  	if p == nil {
    99  		return "<nil>"
   100  	}
   101  	status := p.Sys().(syscall.WaitStatus)
   102  	res := ""
   103  	switch {
   104  	case status.Exited():
   105  		res = "exit status " + itoa(status.ExitStatus())
   106  	case status.Signaled():
   107  		res = "signal: " + status.Signal().String()
   108  	case status.Stopped():
   109  		res = "stop signal: " + status.StopSignal().String()
   110  		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
   111  			res += " (trap " + itoa(status.TrapCause()) + ")"
   112  		}
   113  	case status.Continued():
   114  		res = "continued"
   115  	}
   116  	if status.CoreDump() {
   117  		res += " (core dumped)"
   118  	}
   119  	return res
   120  }
   121  
   122  // ExitCode returns the exit code of the exited process, or -1
   123  // if the process hasn't exited or was terminated by a signal.
   124  func (p *ProcessState) ExitCode() int {
   125  	// return -1 if the process hasn't started.
   126  	if p == nil {
   127  		return -1
   128  	}
   129  	return p.status.ExitStatus()
   130  }
   131
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