pkg/system: move GetExitCode() to pkg/idtools, and un-export

This utility was only used in a single place, and had no external consumers.
Move it to where it's used.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 07b1aa822cc7b371ef5925940d8ea8cfb54de57e)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/idtools/idtools_unix.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strconv"
 	"sync"
@@ -199,7 +200,7 @@ func callGetent(database, key string) (io.Reader, error) {
 	}
 	out, err := execCmd(getentCmd, database, key)
 	if err != nil {
-		exitCode, errC := system.GetExitCode(err)
+		exitCode, errC := getExitCode(err)
 		if errC != nil {
 			return nil, err
 		}
@@ -217,6 +218,18 @@ func callGetent(database, key string) (io.Reader, error) {
 	return bytes.NewReader(out), nil
 }
 
+// getExitCode returns the ExitStatus of the specified error if its type is
+// exec.ExitError, returns 0 and an error otherwise.
+func getExitCode(err error) (int, error) {
+	exitCode := 0
+	if exiterr, ok := err.(*exec.ExitError); ok {
+		if procExit, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+			return procExit.ExitStatus(), nil
+		}
+	}
+	return exitCode, fmt.Errorf("failed to get exit code")
+}
+
 // setPermissions performs a chown/chmod only if the uid/gid don't match what's requested
 // Normally a Chown is a no-op if uid/gid match, but in some cases this can still cause an error, e.g. if the
 // dir is on an NFS share, so don't call chown unless we absolutely must.

pkg/system/exitcode.go

@@ -1,19 +0,0 @@
-package system // import "github.com/docker/docker/pkg/system"
-
-import (
-	"fmt"
-	"os/exec"
-	"syscall"
-)
-
-// GetExitCode returns the ExitStatus of the specified error if its type is
-// exec.ExitError, returns 0 and an error otherwise.
-func GetExitCode(err error) (int, error) {
-	exitCode := 0
-	if exiterr, ok := err.(*exec.ExitError); ok {
-		if procExit, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-			return procExit.ExitStatus(), nil
-		}
-	}
-	return exitCode, fmt.Errorf("failed to get exit code")
-}