exec_posix.go

     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  //go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris || windows
     6  
     7  package os
     8  
     9  import (
    10  	"internal/itoa"
    11  	"internal/syscall/execenv"
    12  	"runtime"
    13  	"syscall"
    14  )
    15  
    16  // The only signal values guaranteed to be present in the os package on all
    17  // systems are os.Interrupt (send the process an interrupt) and os.Kill (force
    18  // the process to exit). On Windows, sending os.Interrupt to a process with
    19  // os.Process.Signal is not implemented; it will return an error instead of
    20  // sending a signal.
    21  var (
    22  	Interrupt Signal = syscall.SIGINT
    23  	Kill      Signal = syscall.SIGKILL
    24  )
    25  
    26  func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
    27  	// If there is no SysProcAttr (ie. no Chroot or changed
    28  	// UID/GID), double-check existence of the directory we want
    29  	// to chdir into. We can make the error clearer this way.
    30  	if attr != nil && attr.Sys == nil && attr.Dir != "" {
    31  		if _, err := Stat(attr.Dir); err != nil {
    32  			pe := err.(*PathError)
    33  			pe.Op = "chdir"
    34  			return nil, pe
    35  		}
    36  	}
    37  
    38  	sysattr := &syscall.ProcAttr{
    39  		Dir: attr.Dir,
    40  		Env: attr.Env,
    41  		Sys: attr.Sys,
    42  	}
    43  	if sysattr.Env == nil {
    44  		sysattr.Env, err = execenv.Default(sysattr.Sys)
    45  		if err != nil {
    46  			return nil, err
    47  		}
    48  	}
    49  	sysattr.Files = make([]uintptr, 0, len(attr.Files))
    50  	for _, f := range attr.Files {
    51  		sysattr.Files = append(sysattr.Files, f.Fd())
    52  	}
    53  
    54  	pid, h, e := syscall.StartProcess(name, argv, sysattr)
    55  
    56  	// Make sure we don't run the finalizers of attr.Files.
    57  	runtime.KeepAlive(attr)
    58  
    59  	if e != nil {
    60  		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
    61  	}
    62  
    63  	return newProcess(pid, h), nil
    64  }
    65  
    66  func (p *Process) kill() error {
    67  	return p.Signal(Kill)
    68  }
    69  
    70  // ProcessState stores information about a process, as reported by Wait.
    71  type ProcessState struct {
    72  	pid    int                // The process's id.
    73  	status syscall.WaitStatus // System-dependent status info.
    74  	rusage *syscall.Rusage
    75  }
    76  
    77  // Pid returns the process id of the exited process.
    78  func (p *ProcessState) Pid() int {
    79  	return p.pid
    80  }
    81  
    82  func (p *ProcessState) exited() bool {
    83  	return p.status.Exited()
    84  }
    85  
    86  func (p *ProcessState) success() bool {
    87  	return p.status.ExitStatus() == 0
    88  }
    89  
    90  func (p *ProcessState) sys() any {
    91  	return p.status
    92  }
    93  
    94  func (p *ProcessState) sysUsage() any {
    95  	return p.rusage
    96  }
    97  
    98  func (p *ProcessState) String() string {
    99  	if p == nil {
   100  		return "<nil>"
   101  	}
   102  	status := p.Sys().(syscall.WaitStatus)
   103  	res := ""
   104  	switch {
   105  	case status.Exited():
   106  		code := status.ExitStatus()
   107  		if runtime.GOOS == "windows" && uint(code) >= 1<<16 { // windows uses large hex numbers
   108  			res = "exit status " + uitox(uint(code))
   109  		} else { // unix systems use small decimal integers
   110  			res = "exit status " + itoa.Itoa(code) // unix
   111  		}
   112  	case status.Signaled():
   113  		res = "signal: " + status.Signal().String()
   114  	case status.Stopped():
   115  		res = "stop signal: " + status.StopSignal().String()
   116  		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
   117  			res += " (trap " + itoa.Itoa(status.TrapCause()) + ")"
   118  		}
   119  	case status.Continued():
   120  		res = "continued"
   121  	}
   122  	if status.CoreDump() {
   123  		res += " (core dumped)"
   124  	}
   125  	return res
   126  }
   127  
   128  // ExitCode returns the exit code of the exited process, or -1
   129  // if the process hasn't exited or was terminated by a signal.
   130  func (p *ProcessState) ExitCode() int {
   131  	// return -1 if the process hasn't started.
   132  	if p == nil {
   133  		return -1
   134  	}
   135  	return p.status.ExitStatus()
   136  }
   137
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