Source: exec_posix.go in package os

+build aix darwin dragonfly freebsd js,wasm linux netbsd openbsd solaris windows


package os

import (
	"internal/syscall/execenv"
	"runtime"
	"syscall"
)

The only signal values guaranteed to be present in the os package on all systems are os.Interrupt (send the process an interrupt) and os.Kill (force the process to exit). On Windows, sending os.Interrupt to a process with os.Process.Signal is not implemented; it will return an error instead of sending a signal.

var (
	Interrupt Signal = syscall.SIGINT
	Kill      Signal = syscall.SIGKILL
)

If there is no SysProcAttr (ie. no Chroot or changed UID/GID), double-check existence of the directory we want to chdir into. We can make the error clearer this way.

	if attr != nil && attr.Sys == nil && attr.Dir != "" {
		if _, err := Stat(attr.Dir); err != nil {
			pe := err.(*PathError)
			pe.Op = "chdir"
			return nil, pe
		}
	}

	sysattr := &syscall.ProcAttr{
		Dir: attr.Dir,
		Env: attr.Env,
		Sys: attr.Sys,
	}
	if sysattr.Env == nil {
		sysattr.Env, err = execenv.Default(sysattr.Sys)
		if err != nil {
			return nil, err
		}
	}
	sysattr.Files = make([]uintptr, 0, len(attr.Files))
	for _, f := range attr.Files {
		sysattr.Files = append(sysattr.Files, f.Fd())
	}

	pid, h, e := syscall.StartProcess(name, argv, sysattr)

Make sure we don't run the finalizers of attr.Files.

	runtime.KeepAlive(attr)

	if e != nil {
		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
	}

	return newProcess(pid, h), nil
}

func (p *Process) kill() error {
	return p.Signal(Kill)
}

ProcessState stores information about a process, as reported by Wait.

type ProcessState struct {
	pid    int                // The process's id.
	status syscall.WaitStatus // System-dependent status info.
	rusage *syscall.Rusage
}

Pid returns the process id of the exited process.

func (p *ProcessState) Pid() int {
	return p.pid
}

func (p *ProcessState) exited() bool {
	return p.status.Exited()
}

func (p *ProcessState) success() bool {
	return p.status.ExitStatus() == 0
}

func (p *ProcessState) sys() interface{} {
	return p.status
}

func (p *ProcessState) sysUsage() interface{} {
	return p.rusage
}

func (p *ProcessState) String() string {
	if p == nil {
		return "<nil>"
	}
	status := p.Sys().(syscall.WaitStatus)
	res := ""
	switch {
	case status.Exited():
		res = "exit status " + itoa(status.ExitStatus())
	case status.Signaled():
		res = "signal: " + status.Signal().String()
	case status.Stopped():
		res = "stop signal: " + status.StopSignal().String()
		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
			res += " (trap " + itoa(status.TrapCause()) + ")"
		}
	case status.Continued():
		res = "continued"
	}
	if status.CoreDump() {
		res += " (core dumped)"
	}
	return res
}

ExitCode returns the exit code of the exited process, or -1 if the process hasn't exited or was terminated by a signal.

return -1 if the process hasn't started.

	if p == nil {
		return -1
	}
	return p.status.ExitStatus()