[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

4 files changed, 28 insertions, 22 deletions

diff --git a/pkg/safecopy/BUILD b/pkg/safecopy/BUILD
index 426ef30c9..b77c40279 100644
--- a/pkg/safecopy/BUILD
+++ b/pkg/safecopy/BUILD
@@ -17,7 +17,10 @@ go_library(
         "sighandler_arm64.s",
     ],
     visibility = ["//:sandbox"],
-    deps = ["//pkg/syserror"],
+    deps = [
+        "//pkg/syserror",
+        "@org_golang_x_sys//unix:go_default_library",
+    ],
 )
 
 go_test(
@@ -26,4 +29,5 @@ go_test(
         "safecopy_test.go",
     ],
     library = ":safecopy",
+    deps = ["@org_golang_x_sys//unix:go_default_library"],
 )
diff --git a/pkg/safecopy/safecopy.go b/pkg/safecopy/safecopy.go
index 2fb7e5809..1e0af5889 100644
--- a/pkg/safecopy/safecopy.go
+++ b/pkg/safecopy/safecopy.go
@@ -20,8 +20,8 @@ import (
 	"fmt"
 	"reflect"
 	"runtime"
-	"syscall"
 
+	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
@@ -127,16 +127,16 @@ func initializeAddresses() {
 
 func init() {
 	initializeAddresses()
-	if err := ReplaceSignalHandler(syscall.SIGSEGV, reflect.ValueOf(signalHandler).Pointer(), &savedSigSegVHandler); err != nil {
+	if err := ReplaceSignalHandler(unix.SIGSEGV, reflect.ValueOf(signalHandler).Pointer(), &savedSigSegVHandler); err != nil {
 		panic(fmt.Sprintf("Unable to set handler for SIGSEGV: %v", err))
 	}
-	if err := ReplaceSignalHandler(syscall.SIGBUS, reflect.ValueOf(signalHandler).Pointer(), &savedSigBusHandler); err != nil {
+	if err := ReplaceSignalHandler(unix.SIGBUS, reflect.ValueOf(signalHandler).Pointer(), &savedSigBusHandler); err != nil {
 		panic(fmt.Sprintf("Unable to set handler for SIGBUS: %v", err))
 	}
-	syserror.AddErrorUnwrapper(func(e error) (syscall.Errno, bool) {
+	syserror.AddErrorUnwrapper(func(e error) (unix.Errno, bool) {
 		switch e.(type) {
 		case SegvError, BusError, AlignmentError:
-			return syscall.EFAULT, true
+			return unix.EFAULT, true
 		default:
 			return 0, false
 		}
diff --git a/pkg/safecopy/safecopy_test.go b/pkg/safecopy/safecopy_test.go
index 7f7f69d61..d2ce8ff86 100644
--- a/pkg/safecopy/safecopy_test.go
+++ b/pkg/safecopy/safecopy_test.go
@@ -21,9 +21,10 @@ import (
 	"math/rand"
 	"os"
 	"runtime/debug"
-	"syscall"
 	"testing"
 	"unsafe"
+
+	"golang.org/x/sys/unix"
 )
 
 // Size of a page in bytes. Cloned from usermem.PageSize to avoid a circular
@@ -224,12 +225,12 @@ func TestCompareAndSwapUint32AlignmentError(t *testing.T) {
 // withSegvErrorTestMapping calls fn with a two-page mapping. The first page
 // contains random data, and the second page generates SIGSEGV when accessed.
 func withSegvErrorTestMapping(t *testing.T, fn func(m []byte)) {
-	mapping, err := syscall.Mmap(-1, 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)
+	mapping, err := unix.Mmap(-1, 0, 2*pageSize, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_ANONYMOUS|unix.MAP_PRIVATE)
 	if err != nil {
 		t.Fatalf("Mmap failed: %v", err)
 	}
-	defer syscall.Munmap(mapping)
-	if err := syscall.Mprotect(mapping[pageSize:], syscall.PROT_NONE); err != nil {
+	defer unix.Munmap(mapping)
+	if err := unix.Mprotect(mapping[pageSize:], unix.PROT_NONE); err != nil {
 		t.Fatalf("Mprotect failed: %v", err)
 	}
 	initRandom(mapping[:pageSize])
@@ -248,11 +249,11 @@ func withBusErrorTestMapping(t *testing.T, fn func(m []byte)) {
 	if err := f.Truncate(pageSize); err != nil {
 		t.Fatalf("Truncate failed: %v", err)
 	}
-	mapping, err := syscall.Mmap(int(f.Fd()), 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
+	mapping, err := unix.Mmap(int(f.Fd()), 0, 2*pageSize, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED)
 	if err != nil {
 		t.Fatalf("Mmap failed: %v", err)
 	}
-	defer syscall.Munmap(mapping)
+	defer unix.Munmap(mapping)
 	initRandom(mapping[:pageSize])
 
 	fn(mapping)
@@ -583,12 +584,12 @@ func TestSegVOnMemmove(t *testing.T) {
 	// Test that SIGSEGVs received by runtime.memmove when *not* doing
 	// CopyIn or CopyOut work gets propagated to the runtime.
 	const bufLen = pageSize
-	a, err := syscall.Mmap(-1, 0, bufLen, syscall.PROT_NONE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	a, err := unix.Mmap(-1, 0, bufLen, unix.PROT_NONE, unix.MAP_ANON|unix.MAP_PRIVATE)
 	if err != nil {
 		t.Fatalf("Mmap failed: %v", err)
 
 	}
-	defer syscall.Munmap(a)
+	defer unix.Munmap(a)
 	b := randBuf(bufLen)
 
 	if !testCopy(b, a) {
@@ -611,12 +612,12 @@ func TestSigbusOnMemmove(t *testing.T) {
 	os.Remove(f.Name())
 	defer f.Close()
 
-	a, err := syscall.Mmap(int(f.Fd()), 0, bufLen, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
+	a, err := unix.Mmap(int(f.Fd()), 0, bufLen, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED)
 	if err != nil {
 		t.Fatalf("Mmap failed: %v", err)
 
 	}
-	defer syscall.Munmap(a)
+	defer unix.Munmap(a)
 	b := randBuf(bufLen)
 
 	if !testCopy(b, a) {
diff --git a/pkg/safecopy/safecopy_unsafe.go b/pkg/safecopy/safecopy_unsafe.go
index 41dd567f3..a075cf88e 100644
--- a/pkg/safecopy/safecopy_unsafe.go
+++ b/pkg/safecopy/safecopy_unsafe.go
@@ -17,8 +17,9 @@ package safecopy
 import (
 	"fmt"
 	"runtime"
-	"syscall"
 	"unsafe"
+
+	"golang.org/x/sys/unix"
 )
 
 // maxRegisterSize is the maximum register size used in memcpy and memclr. It
@@ -310,9 +311,9 @@ func errorFromFaultSignal(addr uintptr, sig int32) error {
 	switch sig {
 	case 0:
 		return nil
-	case int32(syscall.SIGSEGV):
+	case int32(unix.SIGSEGV):
 		return SegvError{addr}
-	case int32(syscall.SIGBUS):
+	case int32(unix.SIGBUS):
 		return BusError{addr}
 	default:
 		panic(fmt.Sprintf("safecopy got unexpected signal %d at address %#x", sig, addr))
@@ -328,7 +329,7 @@ func errorFromFaultSignal(addr uintptr, sig int32) error {
 // handlers for appropriate signals. These handlers will call the previous
 // handler however, and if this is function is being used externally then the
 // same courtesy is expected.
-func ReplaceSignalHandler(sig syscall.Signal, handler uintptr, previous *uintptr) error {
+func ReplaceSignalHandler(sig unix.Signal, handler uintptr, previous *uintptr) error {
 	var sa struct {
 		handler  uintptr
 		flags    uint64
@@ -340,7 +341,7 @@ func ReplaceSignalHandler(sig syscall.Signal, handler uintptr, previous *uintptr
 	// Get the existing signal handler information, and save the current
 	// handler. Once we replace it, we will use this pointer to fall back to
 	// it when we receive other signals.
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
+	if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
 		return e
 	}
 
@@ -353,7 +354,7 @@ func ReplaceSignalHandler(sig syscall.Signal, handler uintptr, previous *uintptr
 
 	// Install our own handler.
 	sa.handler = handler
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
+	if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
 		return e
 	}