[op] Replace syscall package usage with golang.org/x/sys/unix in pkg/.

The syscall package has been deprecated in favor of golang.org/x/sys.

Note that syscall is still used in the following places:
- pkg/sentry/socket/hostinet/stack.go: some netlink related functionalities
  are not yet available in golang.org/x/sys.
- syscall.Stat_t is still used in some places because os.FileInfo.Sys() still
  returns it and not unix.Stat_t.

Updates #214

PiperOrigin-RevId: 360701387

2 files changed, 13 insertions, 14 deletions

diff --git a/pkg/fdnotifier/fdnotifier.go b/pkg/fdnotifier/fdnotifier.go
index a6b63c982..1290d5d10 100644
--- a/pkg/fdnotifier/fdnotifier.go
+++ b/pkg/fdnotifier/fdnotifier.go
@@ -22,7 +22,6 @@ package fdnotifier
 
 import (
 	"fmt"
-	"syscall"
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/sync"
@@ -51,7 +50,7 @@ type notifier struct {
 
 // newNotifier creates a new notifier object.
 func newNotifier() (*notifier, error) {
-	epfd, err := syscall.EpollCreate1(0)
+	epfd, err := unix.EpollCreate1(0)
 	if err != nil {
 		return nil, err
 	}
@@ -72,22 +71,22 @@ func (n *notifier) waitFD(fd int32, fi *fdInfo, mask waiter.EventMask) error {
 		return nil
 	}
 
-	e := syscall.EpollEvent{
+	e := unix.EpollEvent{
 		Events: mask.ToLinux() | unix.EPOLLET,
 		Fd:     fd,
 	}
 
 	switch {
 	case !fi.waiting && mask != 0:
-		if err := syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_ADD, int(fd), &e); err != nil {
+		if err := unix.EpollCtl(n.epFD, unix.EPOLL_CTL_ADD, int(fd), &e); err != nil {
 			return err
 		}
 		fi.waiting = true
 	case fi.waiting && mask == 0:
-		syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_DEL, int(fd), nil)
+		unix.EpollCtl(n.epFD, unix.EPOLL_CTL_DEL, int(fd), nil)
 		fi.waiting = false
 	case fi.waiting && mask != 0:
-		if err := syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_MOD, int(fd), &e); err != nil {
+		if err := unix.EpollCtl(n.epFD, unix.EPOLL_CTL_MOD, int(fd), &e); err != nil {
 			return err
 		}
 	}
@@ -144,10 +143,10 @@ func (n *notifier) hasFD(fd int32) bool {
 // notifications from the epoll object. Once notifications arrive, they are
 // dispatched to the registered queue.
 func (n *notifier) waitAndNotify() error {
-	e := make([]syscall.EpollEvent, 100)
+	e := make([]unix.EpollEvent, 100)
 	for {
 		v, err := epollWait(n.epFD, e, -1)
-		if err == syscall.EINTR {
+		if err == unix.EINTR {
 			continue
 		}
 
diff --git a/pkg/fdnotifier/poll_unsafe.go b/pkg/fdnotifier/poll_unsafe.go
index ec2f997a2..493ea8375 100644
--- a/pkg/fdnotifier/poll_unsafe.go
+++ b/pkg/fdnotifier/poll_unsafe.go
@@ -17,9 +17,9 @@
 package fdnotifier
 
 import (
-	"syscall"
 	"unsafe"
 
+	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
@@ -35,16 +35,16 @@ func NonBlockingPoll(fd int32, mask waiter.EventMask) waiter.EventMask {
 		events: int16(mask.ToLinux()),
 	}
 
-	ts := syscall.Timespec{
+	ts := unix.Timespec{
 		Sec:  0,
 		Nsec: 0,
 	}
 
 	for {
-		n, _, err := syscall.RawSyscall6(syscall.SYS_PPOLL, uintptr(unsafe.Pointer(&e)), 1,
+		n, _, err := unix.RawSyscall6(unix.SYS_PPOLL, uintptr(unsafe.Pointer(&e)), 1,
 			uintptr(unsafe.Pointer(&ts)), 0, 0, 0)
 		// Interrupted by signal, try again.
-		if err == syscall.EINTR {
+		if err == unix.EINTR {
 			continue
 		}
 		// If an error occur we'll conservatively say the FD is ready for
@@ -66,14 +66,14 @@ func NonBlockingPoll(fd int32, mask waiter.EventMask) waiter.EventMask {
 // epollWait performs a blocking wait on epfd.
 //
 // Preconditions: len(events) > 0
-func epollWait(epfd int, events []syscall.EpollEvent, msec int) (int, error) {
+func epollWait(epfd int, events []unix.EpollEvent, msec int) (int, error) {
 	if len(events) == 0 {
 		panic("Empty events passed to EpollWait")
 	}
 
 	// We actually use epoll_pwait with NULL sigmask instead of epoll_wait
 	// since that is what the Go >= 1.11 runtime prefers.
-	r, _, e := syscall.Syscall6(syscall.SYS_EPOLL_PWAIT, uintptr(epfd), uintptr(unsafe.Pointer(&events[0])), uintptr(len(events)), uintptr(msec), 0, 0)
+	r, _, e := unix.Syscall6(unix.SYS_EPOLL_PWAIT, uintptr(epfd), uintptr(unsafe.Pointer(&events[0])), uintptr(len(events)), uintptr(msec), 0, 0)
 	if e != 0 {
 		return 0, e
 	}