Source file src/os/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	// +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, err = environForSysProcAttr(sysattr.Sys)
    42			if err != nil {
    43				return nil, err
    44			}
    45		}
    46		sysattr.Files = make([]uintptr, 0, len(attr.Files))
    47		for _, f := range attr.Files {
    48			sysattr.Files = append(sysattr.Files, f.Fd())
    49		}
    50	
    51		pid, h, e := syscall.StartProcess(name, argv, sysattr)
    52		if e != nil {
    53			return nil, &PathError{"fork/exec", name, e}
    54		}
    55		return newProcess(pid, h), nil
    56	}
    57	
    58	func (p *Process) kill() error {
    59		return p.Signal(Kill)
    60	}
    61	
    62	// ProcessState stores information about a process, as reported by Wait.
    63	type ProcessState struct {
    64		pid    int                // The process's id.
    65		status syscall.WaitStatus // System-dependent status info.
    66		rusage *syscall.Rusage
    67	}
    68	
    69	// Pid returns the process id of the exited process.
    70	func (p *ProcessState) Pid() int {
    71		return p.pid
    72	}
    73	
    74	func (p *ProcessState) exited() bool {
    75		return p.status.Exited()
    76	}
    77	
    78	func (p *ProcessState) success() bool {
    79		return p.status.ExitStatus() == 0
    80	}
    81	
    82	func (p *ProcessState) sys() interface{} {
    83		return p.status
    84	}
    85	
    86	func (p *ProcessState) sysUsage() interface{} {
    87		return p.rusage
    88	}
    89	
    90	func (p *ProcessState) String() string {
    91		if p == nil {
    92			return "<nil>"
    93		}
    94		status := p.Sys().(syscall.WaitStatus)
    95		res := ""
    96		switch {
    97		case status.Exited():
    98			res = "exit status " + itoa(status.ExitStatus())
    99		case status.Signaled():
   100			res = "signal: " + status.Signal().String()
   101		case status.Stopped():
   102			res = "stop signal: " + status.StopSignal().String()
   103			if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
   104				res += " (trap " + itoa(status.TrapCause()) + ")"
   105			}
   106		case status.Continued():
   107			res = "continued"
   108		}
   109		if status.CoreDump() {
   110			res += " (core dumped)"
   111		}
   112		return res
   113	}
   114	
   115	// ExitCode returns the exit code of the exited process, or -1
   116	// if the process hasn't exited or was terminated by a signal.
   117	func (p *ProcessState) ExitCode() int {
   118		// return -1 if the process hasn't started.
   119		if p == nil {
   120			return -1
   121		}
   122		return p.status.ExitStatus()
   123	}
   124	

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