pkg/commandhandler/cmd_linux.go

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
package commandhandler

import (
	"fmt"
	"github.com/pkg/errors"
	"io"
	"os"
	"os/exec"
	"syscall"
)

func execWait(cmd, workdir string, stdout, stderr io.WriteCloser) (int, error) {
	defer stdout.Close()
	defer stderr.Close()
	return execCommonWithEnvVariables(workdir, stdout, stderr, func(c *exec.Cmd) error {
		return c.Run()
	}, nil, cmd)
}

func execWaitWithEnvVariables(cmd, workdir string, stdout, stderr io.WriteCloser, params *map[string]string) (int, error) {
	defer stdout.Close()
	defer stderr.Close()
	return execCommonWithEnvVariables(workdir, stdout, stderr, func(c *exec.Cmd) error {
		return c.Run()
	}, params, cmd)
}

func execDontWait(cmd, workdir string) (int, error) {
	// passing '&' as a trailing parameter to /bin/sh in addition (*exec.Command).Start() to will double fork and prevent zombie processes
	return execCommonWithEnvVariables(workdir, os.Stdout, os.Stderr, func(c *exec.Cmd) error {
		return c.Start()
	}, nil, cmd, "&")
}

func execDontWaitWithEnvVariables(cmd, workdir string, params *map[string]string) (int, error) {
	return execCommonWithEnvVariables(workdir, os.Stdout, os.Stderr, func(c *exec.Cmd) error {
		return c.Start()
	}, params, cmd, "&")
}

func execCommonWithEnvVariables(workdir string, stdout, stderr io.WriteCloser, execMethodToCall func(*exec.Cmd) error, params *map[string]string, args ...string) (int, error) {

	args = append([]string{"-c"}, args...)
	c := exec.Command("/bin/sh", args...)
	c.Dir = workdir
	c.Stdout = stdout
	c.Stderr = stderr
	c.Env = os.Environ()

	addEnvVariables(params, c)

	err := execMethodToCall(c)
	exitErr, ok := err.(*exec.ExitError)
	if ok {
		if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
			code := status.ExitStatus()
			return code, fmt.Errorf("command terminated with exit status=%d", code)
		}
	}
	if err != nil {
		return 1, errors.Wrapf(err, "failed to execute command")
	}
	return 0, nil
}