[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

3 files changed, 9 insertions, 6 deletions

diff --git a/pkg/sentry/sighandling/BUILD b/pkg/sentry/sighandling/BUILD
index 6c38a3f44..1790d57c9 100644
--- a/pkg/sentry/sighandling/BUILD
+++ b/pkg/sentry/sighandling/BUILD
@@ -9,5 +9,8 @@ go_library(
         "sighandling_unsafe.go",
     ],
     visibility = ["//pkg/sentry:internal"],
-    deps = ["//pkg/abi/linux"],
+    deps = [
+        "//pkg/abi/linux",
+        "@org_golang_x_sys//unix:go_default_library",
+    ],
 )
diff --git a/pkg/sentry/sighandling/sighandling.go b/pkg/sentry/sighandling/sighandling.go
index 83195d5a1..bdaf8af29 100644
--- a/pkg/sentry/sighandling/sighandling.go
+++ b/pkg/sentry/sighandling/sighandling.go
@@ -19,8 +19,8 @@ import (
 	"os"
 	"os/signal"
 	"reflect"
-	"syscall"
 
+	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
 )
 
@@ -90,7 +90,7 @@ func StartSignalForwarding(handler func(linux.Signal)) func() {
 		if sig == int(linux.SIGURG) {
 			continue
 		}
-		signal.Notify(sigchan, syscall.Signal(sig))
+		signal.Notify(sigchan, unix.Signal(sig))
 	}
 	// Start up our listener.
 	go handleSignals(sigchans, handler, stop, done) // S/R-SAFE: synchronized by Kernel.extMu.
diff --git a/pkg/sentry/sighandling/sighandling_unsafe.go b/pkg/sentry/sighandling/sighandling_unsafe.go
index 1ebe22d34..d6a2fbe34 100644
--- a/pkg/sentry/sighandling/sighandling_unsafe.go
+++ b/pkg/sentry/sighandling/sighandling_unsafe.go
@@ -15,9 +15,9 @@
 package sighandling
 
 import (
-	"syscall"
 	"unsafe"
 
+	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
 )
 
@@ -36,11 +36,11 @@ func IgnoreChildStop() error {
 	var sa sigaction
 
 	// Get the existing signal handler information, and set the flag.
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(syscall.SIGCHLD), 0, uintptr(unsafe.Pointer(&sa)), linux.SignalSetSize, 0, 0); e != 0 {
+	if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), 0, uintptr(unsafe.Pointer(&sa)), linux.SignalSetSize, 0, 0); e != 0 {
 		return e
 	}
 	sa.flags |= linux.SA_NOCLDSTOP
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(syscall.SIGCHLD), uintptr(unsafe.Pointer(&sa)), 0, linux.SignalSetSize, 0, 0); e != 0 {
+	if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), uintptr(unsafe.Pointer(&sa)), 0, linux.SignalSetSize, 0, 0); e != 0 {
 		return e
 	}