Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 69 insertions, 0 deletions

diff --git a/pkg/sentry/syscalls/linux/sigset.go b/pkg/sentry/syscalls/linux/sigset.go
new file mode 100644
index 000000000..bfb541634
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sigset.go
@@ -0,0 +1,69 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+import (
+	"syscall"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// copyInSigSet copies in a sigset_t, checks its size, and ensures that KILL and
+// STOP are clear.
+func copyInSigSet(t *kernel.Task, sigSetAddr usermem.Addr, size uint) (linux.SignalSet, error) {
+	if size != linux.SignalSetSize {
+		return 0, syscall.EINVAL
+	}
+	b := t.CopyScratchBuffer(8)
+	if _, err := t.CopyInBytes(sigSetAddr, b); err != nil {
+		return 0, err
+	}
+	mask := usermem.ByteOrder.Uint64(b[:])
+	return linux.SignalSet(mask) &^ kernel.UnblockableSignals, nil
+}
+
+// copyOutSigSet copies out a sigset_t.
+func copyOutSigSet(t *kernel.Task, sigSetAddr usermem.Addr, mask linux.SignalSet) error {
+	b := t.CopyScratchBuffer(8)
+	usermem.ByteOrder.PutUint64(b, uint64(mask))
+	_, err := t.CopyOutBytes(sigSetAddr, b)
+	return err
+}
+
+// copyInSigSetWithSize copies in a structure as below
+//
+//   struct {
+//       sigset_t* sigset_addr;
+//       size_t sizeof_sigset;
+//   };
+//
+// and returns sigset_addr and size.
+func copyInSigSetWithSize(t *kernel.Task, addr usermem.Addr) (usermem.Addr, uint, error) {
+	switch t.Arch().Width() {
+	case 8:
+		in := t.CopyScratchBuffer(16)
+		if _, err := t.CopyInBytes(addr, in); err != nil {
+			return 0, 0, err
+		}
+		maskAddr := usermem.Addr(usermem.ByteOrder.Uint64(in[0:]))
+		maskSize := uint(usermem.ByteOrder.Uint64(in[8:]))
+		return maskAddr, maskSize, nil
+	default:
+		return 0, 0, syserror.ENOSYS
+	}
+}