Prefer `golang.org/x/sys/unix` where appropriate

Favor the `unix` package on *NIX platforms vs the now frozen `syscall` package.

client/allocdir/alloc_dir_unix.go

@@ -8,7 +8,8 @@ import (
 	"os"
 	"os/user"
 	"strconv"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 func (d *AllocDir) linkOrCopy(src, dst string, perm os.FileMode) error {
@@ -22,7 +23,7 @@ func (d *AllocDir) linkOrCopy(src, dst string, perm os.FileMode) error {
 
 func (d *AllocDir) dropDirPermissions(path string) error {
 	// Can't do anything if not root.
-	if syscall.Geteuid() != 0 {
+	if unix.Geteuid() != 0 {
 		return nil
 	}
 

client/driver/exec.go

@@ -7,9 +7,10 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
-	"syscall"
 	"time"
 
+	"golang.org/x/sys/unix"
+
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/nomad/client/allocdir"
@@ -93,7 +94,7 @@ func (d *ExecDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool,
 		}
 		delete(node.Attributes, execDriverAttr)
 		return false, nil
-	} else if syscall.Geteuid() != 0 {
+	} else if unix.Geteuid() != 0 {
 		if currentlyEnabled {
 			d.logger.Printf("[DEBUG] driver.exec: must run as root user, disabling")
 		}

client/driver/executor/executor.go

@@ -11,7 +11,6 @@ import (
 	"runtime"
 	"strings"
 	"sync"
-	"syscall"
 	"time"
 
 	"github.com/hashicorp/go-multierror"
@@ -324,31 +323,6 @@ func (e *UniversalExecutor) UpdateTask(task *structs.Task) error {
 	return nil
 }
 
-func (e *UniversalExecutor) wait() {
-	defer close(e.processExited)
-	err := e.cmd.Wait()
-	ic := &cstructs.IsolationConfig{Cgroup: e.groups, CgroupPaths: e.cgPaths}
-	if err == nil {
-		e.exitState = &ProcessState{Pid: 0, ExitCode: 0, IsolationConfig: ic, Time: time.Now()}
-		return
-	}
-	exitCode := 1
-	var signal int
-	if exitErr, ok := err.(*exec.ExitError); ok {
-		if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
-			exitCode = status.ExitStatus()
-			if status.Signaled() {
-				signal = int(status.Signal())
-				exitCode = 128 + signal
-			}
-		}
-	} else {
-		e.logger.Printf("[DEBUG] executor: unexpected Wait() error type: %v", err)
-	}
-
-	e.exitState = &ProcessState{Pid: 0, ExitCode: exitCode, Signal: signal, IsolationConfig: ic, Time: time.Now()}
-}
-
 var (
 	// finishedErr is the error message received when trying to kill and already
 	// exited process.

client/driver/executor/executor_unix.go

@@ -6,6 +6,10 @@ import (
 	"fmt"
 	"io"
 	"log/syslog"
+	"os/exec"
+	"time"
+
+	"golang.org/x/sys/unix"
 
 	"github.com/hashicorp/nomad/client/driver/logging"
 )
@@ -48,3 +52,28 @@ func (e *UniversalExecutor) collectLogs(we io.Writer, wo io.Writer) {
 		}
 	}
 }
+
+func (e *UniversalExecutor) wait() {
+	defer close(e.processExited)
+	err := e.cmd.Wait()
+	ic := &cstructs.IsolationConfig{Cgroup: e.groups, CgroupPaths: e.cgPaths}
+	if err == nil {
+		e.exitState = &ProcessState{Pid: 0, ExitCode: 0, IsolationConfig: ic, Time: time.Now()}
+		return
+	}
+	exitCode := 1
+	var signal int
+	if exitErr, ok := err.(*exec.ExitError); ok {
+		if status, ok := exitErr.Sys().(unix.WaitStatus); ok {
+			exitCode = status.ExitStatus()
+			if status.Signaled() {
+				signal = int(status.Signal())
+				exitCode = 128 + signal
+			}
+		}
+	} else {
+		e.logger.Printf("[DEBUG] executor: unexpected Wait() error type: %v", err)
+	}
+
+	e.exitState = &ProcessState{Pid: 0, ExitCode: exitCode, Signal: signal, IsolationConfig: ic, Time: time.Now()}
+}