packer-cn/builder/qemu/driver.go

216 lines
4.4 KiB
Go

package qemu
import (
"bufio"
"bytes"
"fmt"
"io"
"log"
"os/exec"
"regexp"
"strings"
"sync"
"syscall"
"time"
"unicode"
"github.com/mitchellh/multistep"
)
type DriverCancelCallback func(state multistep.StateBag) bool
// A driver is able to talk to qemu-system-x86_64 and perform certain
// operations with it.
type Driver interface {
// Stop stops a running machine, forcefully.
Stop() error
// Qemu executes the given command via qemu-system-x86_64
Qemu(qemuArgs ...string) error
// wait on shutdown of the VM with option to cancel
WaitForShutdown(<-chan struct{}) bool
// Qemu executes the given command via qemu-img
QemuImg(...string) error
// Verify checks to make sure that this driver should function
// properly. If there is any indication the driver can't function,
// this will return an error.
Verify() error
// Version reads the version of Qemu that is installed.
Version() (string, error)
}
type QemuDriver struct {
QemuPath string
QemuImgPath string
vmCmd *exec.Cmd
vmEndCh <-chan int
lock sync.Mutex
}
func (d *QemuDriver) Stop() error {
d.lock.Lock()
defer d.lock.Unlock()
if d.vmCmd != nil {
if err := d.vmCmd.Process.Kill(); err != nil {
return err
}
}
return nil
}
func (d *QemuDriver) Qemu(qemuArgs ...string) error {
d.lock.Lock()
defer d.lock.Unlock()
if d.vmCmd != nil {
panic("Existing VM state found")
}
stdout_r, stdout_w := io.Pipe()
stderr_r, stderr_w := io.Pipe()
log.Printf("Executing %s: %#v", d.QemuPath, qemuArgs)
cmd := exec.Command(d.QemuPath, qemuArgs...)
cmd.Stdout = stdout_w
cmd.Stderr = stderr_w
err := cmd.Start()
if err != nil {
err = fmt.Errorf("Error starting VM: %s", err)
return err
}
go logReader("Qemu stdout", stdout_r)
go logReader("Qemu stderr", stderr_r)
log.Printf("Started Qemu. Pid: %d", cmd.Process.Pid)
// Wait for Qemu to complete in the background, and mark when its done
endCh := make(chan int, 1)
go func() {
defer stderr_w.Close()
defer stdout_w.Close()
var exitCode int = 0
if err := cmd.Wait(); err != nil {
if exiterr, ok := err.(*exec.ExitError); ok {
// The program has exited with an exit code != 0
if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
exitCode = status.ExitStatus()
} else {
exitCode = 254
}
}
}
endCh <- exitCode
d.lock.Lock()
defer d.lock.Unlock()
d.vmCmd = nil
d.vmEndCh = nil
}()
// Wait at least a couple seconds for an early fail from Qemu so
// we can report that.
select {
case exit := <-endCh:
if exit != 0 {
return fmt.Errorf("Qemu failed to start. Please run with PACKER_LOG=1 to get more info.")
}
case <-time.After(2 * time.Second):
}
// Setup our state so we know we are running
d.vmCmd = cmd
d.vmEndCh = endCh
return nil
}
func (d *QemuDriver) WaitForShutdown(cancelCh <-chan struct{}) bool {
d.lock.Lock()
endCh := d.vmEndCh
d.lock.Unlock()
if endCh == nil {
return true
}
select {
case <-endCh:
return true
case <-cancelCh:
return false
}
}
func (d *QemuDriver) QemuImg(args ...string) error {
var stdout, stderr bytes.Buffer
log.Printf("Executing qemu-img: %#v", args)
cmd := exec.Command(d.QemuImgPath, args...)
cmd.Stdout = &stdout
cmd.Stderr = &stderr
err := cmd.Run()
stdoutString := strings.TrimSpace(stdout.String())
stderrString := strings.TrimSpace(stderr.String())
if _, ok := err.(*exec.ExitError); ok {
err = fmt.Errorf("QemuImg error: %s", stderrString)
}
log.Printf("stdout: %s", stdoutString)
log.Printf("stderr: %s", stderrString)
return err
}
func (d *QemuDriver) Verify() error {
return nil
}
func (d *QemuDriver) Version() (string, error) {
var stdout bytes.Buffer
cmd := exec.Command(d.QemuPath, "-version")
cmd.Stdout = &stdout
if err := cmd.Run(); err != nil {
return "", err
}
versionOutput := strings.TrimSpace(stdout.String())
log.Printf("Qemu --version output: %s", versionOutput)
versionRe := regexp.MustCompile("[\\.[0-9]+]*")
matches := versionRe.FindStringSubmatch(versionOutput)
if len(matches) == 0 {
return "", fmt.Errorf("No version found: %s", versionOutput)
}
log.Printf("Qemu version: %s", matches[0])
return matches[0], nil
}
func logReader(name string, r io.Reader) {
bufR := bufio.NewReader(r)
for {
line, err := bufR.ReadString('\n')
if line != "" {
line = strings.TrimRightFunc(line, unicode.IsSpace)
log.Printf("%s: %s", name, line)
}
if err == io.EOF {
break
}
}
}