2 files changed, 14 insertions, 11 deletions
diff --git a/pkg/sentry/fsimpl/signalfd/BUILD b/pkg/sentry/fsimpl/signalfd/BUILD
index 067c1657f..adb610213 100644
--- a/pkg/sentry/fsimpl/signalfd/BUILD
+++ b/pkg/sentry/fsimpl/signalfd/BUILD
@@ -8,7 +8,6 @@ go_library(
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
-        "//pkg/binary",
         "//pkg/context",
         "//pkg/sentry/kernel",
         "//pkg/sentry/vfs",
diff --git a/pkg/sentry/fsimpl/signalfd/signalfd.go b/pkg/sentry/fsimpl/signalfd/signalfd.go
index 6297e1df4..10f1452ef 100644
--- a/pkg/sentry/fsimpl/signalfd/signalfd.go
+++ b/pkg/sentry/fsimpl/signalfd/signalfd.go
@@ -16,7 +16,6 @@ package signalfd
 
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
@@ -26,7 +25,9 @@ import (
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
-// SignalFileDescription implements FileDescriptionImpl for signal fds.
+// SignalFileDescription implements vfs.FileDescriptionImpl for signal fds.
+//
+// +stateify savable
 type SignalFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
@@ -43,7 +44,7 @@ type SignalFileDescription struct {
 	target *kernel.Task
 
 	// mu protects mask.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// mask is the signal mask. Protected by mu.
 	mask linux.SignalSet
@@ -83,7 +84,7 @@ func (sfd *SignalFileDescription) SetMask(mask linux.SignalSet) {
 	sfd.mask = mask
 }
 
-// Read implements FileDescriptionImpl.Read.
+// Read implements vfs.FileDescriptionImpl.Read.
 func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) {
 	// Attempt to dequeue relevant signals.
 	info, err := sfd.target.Sigtimedwait(sfd.Mask(), 0)
@@ -93,8 +94,7 @@ func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequen
 	}
 
 	// Copy out the signal info using the specified format.
-	var buf [128]byte
-	binary.Marshal(buf[:0], usermem.ByteOrder, &linux.SignalfdSiginfo{
+	infoNative := linux.SignalfdSiginfo{
 		Signo:   uint32(info.Signo),
 		Errno:   info.Errno,
 		Code:    info.Code,
@@ -103,9 +103,13 @@ func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequen
 		Status:  info.Status(),
 		Overrun: uint32(info.Overrun()),
 		Addr:    info.Addr(),
-	})
-	n, err := dst.CopyOut(ctx, buf[:])
-	return int64(n), err
+	}
+	n, err := infoNative.WriteTo(dst.Writer(ctx))
+	if err == usermem.ErrEndOfIOSequence {
+		// Partial copy-out ok.
+		err = nil
+	}
+	return n, err
 }
 
 // Readiness implements waiter.Waitable.Readiness.
@@ -132,5 +136,5 @@ func (sfd *SignalFileDescription) EventUnregister(entry *waiter.Entry) {
 	sfd.target.SignalUnregister(entry)
 }
 
-// Release implements FileDescriptionImpl.Release()
+// Release implements vfs.FileDescriptionImpl.Release.
 func (sfd *SignalFileDescription) Release(context.Context) {}