libpod: if slirp4netns fails, return its output
read the slirp4netns stderr and propagate it in the error when the
process fails.
Replace:
@@ -5,6 +5,7 @@ package libpod
import (
"crypto/rand"
"fmt"
+ "io/ioutil"
"net"
"os"
"os/exec"
@@ -131,7 +132,7 @@ func checkSlirpFlags(path string) (bool, bool, bool, error) {
cmd := exec.Command(path, "--help")
out, err := cmd.CombinedOutput()
if err != nil {
- return false, false, false, err
+ return false, false, false, errors.Wrapf(err, "slirp4netns %q", out)
}
return strings.Contains(string(out), "--disable-host-loopback"), strings.Contains(string(out), "--mtu"), strings.Contains(string(out), "--enable-sandbox"), nil
}
@@ -158,6 +159,7 @@ func (r *Runtime) setupRootlessNetNS(ctr *Container) (err error) {
havePortMapping := len(ctr.Config().PortMappings) > 0
apiSocket := filepath.Join(ctr.runtime.config.TmpDir, fmt.Sprintf("%s.net", ctr.config.ID))
+ logPath := filepath.Join(ctr.runtime.config.TmpDir, fmt.Sprintf("slirp4netns-%s.log", ctr.config.ID))
cmdArgs := []string{}
if havePortMapping {
@@ -165,7 +167,7 @@ func (r *Runtime) setupRootlessNetNS(ctr *Container) (err error) {
}
dhp, mtu, sandbox, err := checkSlirpFlags(path)
if err != nil {
- return errors.Wrapf(err, "error checking slirp4netns binary %s", path)
+ return errors.Wrapf(err, "error checking slirp4netns binary %s: %q", path, err)
}
if dhp {
cmdArgs = append(cmdArgs, "--disable-host-loopback")
@@ -210,6 +212,18 @@ func (r *Runtime) setupRootlessNetNS(ctr *Container) (err error) {
// Leak one end of the pipe in slirp4netns, the other will be sent to conmon
cmd.ExtraFiles = append(cmd.ExtraFiles, ctr.rootlessSlirpSyncR, syncW)
+ logFile, err := os.Create(logPath)
+ if err != nil {
+ return errors.Wrapf(err, "failed to open slirp4netns log file %s", logPath)
+ }
+ defer logFile.Close()
+ // Unlink immediately the file so we won't need to worry about cleaning it up later.
+ // It is still accessible through the open fd logFile.
+ if err := os.Remove(logPath); err != nil {
+ return errors.Wrapf(err, "delete file %s", logPath)
+ }
+ cmd.Stdout = logFile
+ cmd.Stderr = logFile
if err := cmd.Start(); err != nil {
return errors.Wrapf(err, "failed to start slirp4netns process")
}
@@ -238,7 +252,15 @@ func (r *Runtime) setupRootlessNetNS(ctr *Container) (err error) {
continue
}
if status.Exited() {
- return errors.New("slirp4netns failed")
+ // Seek at the beginning of the file and read all its content
+ if _, err := logFile.Seek(0, 0); err != nil {
+ logrus.Errorf("could not seek log file: %q", err)
+ }
+ logContent, err := ioutil.ReadAll(logFile)
+ if err != nil {
+ return errors.Wrapf(err, "slirp4netns failed")
+ }
+ return errors.Errorf("slirp4netns failed: %q", logContent)
}
if status.Signaled() {
return errors.New("slirp4netns killed by signal")
