Move pkg/sentry/vfs/{eventfd,timerfd} to new packages in pkg/sentry/fsimpl.

They don't depend on anything in VFS2, so they should be their own packages.

PiperOrigin-RevId: 310416807

11 files changed, 107 insertions, 49 deletions

diff --git a/pkg/sentry/fsimpl/eventfd/BUILD b/pkg/sentry/fsimpl/eventfd/BUILD
new file mode 100644
index 000000000..ea167d38c
--- /dev/null
+++ b/pkg/sentry/fsimpl/eventfd/BUILD
@@ -0,0 +1,33 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+
+licenses(["notice"])
+
+go_library(
+    name = "eventfd",
+    srcs = ["eventfd.go"],
+    visibility = ["//pkg/sentry:internal"],
+    deps = [
+        "//pkg/abi/linux",
+        "//pkg/context",
+        "//pkg/fdnotifier",
+        "//pkg/log",
+        "//pkg/sentry/vfs",
+        "//pkg/syserror",
+        "//pkg/usermem",
+        "//pkg/waiter",
+    ],
+)
+
+go_test(
+    name = "eventfd_test",
+    size = "small",
+    srcs = ["eventfd_test.go"],
+    library = ":eventfd",
+    deps = [
+        "//pkg/abi/linux",
+        "//pkg/sentry/contexttest",
+        "//pkg/sentry/vfs",
+        "//pkg/usermem",
+        "//pkg/waiter",
+    ],
+)
diff --git a/pkg/sentry/vfs/eventfd.go b/pkg/sentry/fsimpl/eventfd/eventfd.go
index f39dacacf..c573d7935 100644
--- a/pkg/sentry/vfs/eventfd.go
+++ b/pkg/sentry/fsimpl/eventfd/eventfd.go
@@ -12,7 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package vfs
+// Package eventfd implements event fds.
+package eventfd
 
 import (
 	"math"
@@ -23,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/fdnotifier"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/pkg/waiter"
@@ -32,9 +34,9 @@ import (
 // notification (eventfd). Eventfds are usually internal to the Sentry but in
 // certain situations they may be converted into a host-backed eventfd.
 type EventFileDescription struct {
-	vfsfd FileDescription
-	FileDescriptionDefaultImpl
-	DentryMetadataFileDescriptionImpl
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
 
 	// queue is used to notify interested parties when the event object
 	// becomes readable or writable.
@@ -53,18 +55,18 @@ type EventFileDescription struct {
 	hostfd int
 }
 
-var _ FileDescriptionImpl = (*EventFileDescription)(nil)
+var _ vfs.FileDescriptionImpl = (*EventFileDescription)(nil)
 
-// NewEventFD creates a new event fd.
-func (vfs *VirtualFilesystem) NewEventFD(initVal uint64, semMode bool, flags uint32) (*FileDescription, error) {
-	vd := vfs.NewAnonVirtualDentry("[eventfd]")
+// New creates a new event fd.
+func New(vfsObj *vfs.VirtualFilesystem, initVal uint64, semMode bool, flags uint32) (*vfs.FileDescription, error) {
+	vd := vfsObj.NewAnonVirtualDentry("[eventfd]")
 	defer vd.DecRef()
 	efd := &EventFileDescription{
 		val:     initVal,
 		semMode: semMode,
 		hostfd:  -1,
 	}
-	if err := efd.vfsfd.Init(efd, flags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{
+	if err := efd.vfsfd.Init(efd, flags, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{
 		UseDentryMetadata: true,
 		DenyPRead:         true,
 		DenyPWrite:        true,
@@ -117,7 +119,7 @@ func (efd *EventFileDescription) Release() {
 }
 
 // Read implements FileDescriptionImpl.Read.
-func (efd *EventFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ ReadOptions) (int64, error) {
+func (efd *EventFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) {
 	if dst.NumBytes() < 8 {
 		return 0, syscall.EINVAL
 	}
@@ -128,7 +130,7 @@ func (efd *EventFileDescription) Read(ctx context.Context, dst usermem.IOSequenc
 }
 
 // Write implements FileDescriptionImpl.Write.
-func (efd *EventFileDescription) Write(ctx context.Context, src usermem.IOSequence, _ WriteOptions) (int64, error) {
+func (efd *EventFileDescription) Write(ctx context.Context, src usermem.IOSequence, _ vfs.WriteOptions) (int64, error) {
 	if src.NumBytes() < 8 {
 		return 0, syscall.EINVAL
 	}
diff --git a/pkg/sentry/vfs/eventfd_test.go b/pkg/sentry/fsimpl/eventfd/eventfd_test.go
index 2dff2d10b..20e3adffc 100644
--- a/pkg/sentry/vfs/eventfd_test.go
+++ b/pkg/sentry/fsimpl/eventfd/eventfd_test.go
@@ -12,13 +12,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package vfs
+package eventfd
 
 import (
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/contexttest"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
@@ -34,15 +35,15 @@ func TestEventFD(t *testing.T) {
 
 	for _, initVal := range initVals {
 		ctx := contexttest.Context(t)
-		vfsObj := &VirtualFilesystem{}
+		vfsObj := &vfs.VirtualFilesystem{}
 		if err := vfsObj.Init(); err != nil {
 			t.Fatalf("VFS init: %v", err)
 		}
 
 		// Make a new eventfd that is writable.
-		eventfd, err := vfsObj.NewEventFD(initVal, false, linux.O_RDWR)
+		eventfd, err := New(vfsObj, initVal, false, linux.O_RDWR)
 		if err != nil {
-			t.Fatalf("NewEventFD failed: %v", err)
+			t.Fatalf("New() failed: %v", err)
 		}
 		defer eventfd.DecRef()
 
@@ -53,7 +54,7 @@ func TestEventFD(t *testing.T) {
 
 		data := []byte("00000124")
 		// Create and submit a write request.
-		n, err := eventfd.Write(ctx, usermem.BytesIOSequence(data), WriteOptions{})
+		n, err := eventfd.Write(ctx, usermem.BytesIOSequence(data), vfs.WriteOptions{})
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -72,19 +73,19 @@ func TestEventFD(t *testing.T) {
 
 func TestEventFDStat(t *testing.T) {
 	ctx := contexttest.Context(t)
-	vfsObj := &VirtualFilesystem{}
+	vfsObj := &vfs.VirtualFilesystem{}
 	if err := vfsObj.Init(); err != nil {
 		t.Fatalf("VFS init: %v", err)
 	}
 
 	// Make a new eventfd that is writable.
-	eventfd, err := vfsObj.NewEventFD(0, false, linux.O_RDWR)
+	eventfd, err := New(vfsObj, 0, false, linux.O_RDWR)
 	if err != nil {
-		t.Fatalf("NewEventFD failed: %v", err)
+		t.Fatalf("New() failed: %v", err)
 	}
 	defer eventfd.DecRef()
 
-	statx, err := eventfd.Stat(ctx, StatOptions{
+	statx, err := eventfd.Stat(ctx, vfs.StatOptions{
 		Mask: linux.STATX_BASIC_STATS,
 	})
 	if err != nil {
diff --git a/pkg/sentry/fsimpl/timerfd/BUILD b/pkg/sentry/fsimpl/timerfd/BUILD
new file mode 100644
index 000000000..fbb02a271
--- /dev/null
+++ b/pkg/sentry/fsimpl/timerfd/BUILD
@@ -0,0 +1,17 @@
+load("//tools:defs.bzl", "go_library")
+
+licenses(["notice"])
+
+go_library(
+    name = "timerfd",
+    srcs = ["timerfd.go"],
+    visibility = ["//pkg/sentry:internal"],
+    deps = [
+        "//pkg/context",
+        "//pkg/sentry/kernel/time",
+        "//pkg/sentry/vfs",
+        "//pkg/syserror",
+        "//pkg/usermem",
+        "//pkg/waiter",
+    ],
+)
diff --git a/pkg/sentry/vfs/timerfd.go b/pkg/sentry/fsimpl/timerfd/timerfd.go
index cc536ceaf..60c92d626 100644
--- a/pkg/sentry/vfs/timerfd.go
+++ b/pkg/sentry/fsimpl/timerfd/timerfd.go
@@ -12,13 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package vfs
+// Package timerfd implements timer fds.
+package timerfd
 
 import (
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/context"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/pkg/waiter"
@@ -27,9 +29,9 @@ import (
 // TimerFileDescription implements FileDescriptionImpl for timer fds. It also
 // implements ktime.TimerListener.
 type TimerFileDescription struct {
-	vfsfd FileDescription
-	FileDescriptionDefaultImpl
-	DentryMetadataFileDescriptionImpl
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
 
 	events waiter.Queue
 	timer  *ktime.Timer
@@ -40,16 +42,16 @@ type TimerFileDescription struct {
 	val uint64
 }
 
-var _ FileDescriptionImpl = (*TimerFileDescription)(nil)
+var _ vfs.FileDescriptionImpl = (*TimerFileDescription)(nil)
 var _ ktime.TimerListener = (*TimerFileDescription)(nil)
 
-// NewTimerFD returns a new timer fd.
-func (vfs *VirtualFilesystem) NewTimerFD(clock ktime.Clock, flags uint32) (*FileDescription, error) {
-	vd := vfs.NewAnonVirtualDentry("[timerfd]")
+// New returns a new timer fd.
+func New(vfsObj *vfs.VirtualFilesystem, clock ktime.Clock, flags uint32) (*vfs.FileDescription, error) {
+	vd := vfsObj.NewAnonVirtualDentry("[timerfd]")
 	defer vd.DecRef()
 	tfd := &TimerFileDescription{}
 	tfd.timer = ktime.NewTimer(clock, tfd)
-	if err := tfd.vfsfd.Init(tfd, flags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{
+	if err := tfd.vfsfd.Init(tfd, flags, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{
 		UseDentryMetadata: true,
 		DenyPRead:         true,
 		DenyPWrite:        true,
@@ -60,7 +62,7 @@ func (vfs *VirtualFilesystem) NewTimerFD(clock ktime.Clock, flags uint32) (*File
 }
 
 // Read implements FileDescriptionImpl.Read.
-func (tfd *TimerFileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts ReadOptions) (int64, error) {
+func (tfd *TimerFileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
 	const sizeofUint64 = 8
 	if dst.NumBytes() < sizeofUint64 {
 		return 0, syserror.EINVAL
diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index e47af66d6..8104f50f3 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -172,6 +172,7 @@ go_library(
         "//pkg/sentry/fsimpl/kernfs",
         "//pkg/sentry/fsimpl/pipefs",
         "//pkg/sentry/fsimpl/sockfs",
+        "//pkg/sentry/fsimpl/timerfd",
         "//pkg/sentry/hostcpu",
         "//pkg/sentry/inet",
         "//pkg/sentry/kernel/auth",
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index c91b9dce2..271ea5faf 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -48,10 +48,11 @@ import (
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
-	"gvisor.dev/gvisor/pkg/sentry/fs/timerfd"
+	oldtimerfd "gvisor.dev/gvisor/pkg/sentry/fs/timerfd"
 	"gvisor.dev/gvisor/pkg/sentry/fsbridge"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/pipefs"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/timerfd"
 	"gvisor.dev/gvisor/pkg/sentry/hostcpu"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
@@ -1068,11 +1069,11 @@ func (k *Kernel) pauseTimeLocked() {
 		if t.fdTable != nil {
 			t.fdTable.forEach(func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) {
 				if VFS2Enabled {
-					if tfd, ok := fd.Impl().(*vfs.TimerFileDescription); ok {
+					if tfd, ok := fd.Impl().(*timerfd.TimerFileDescription); ok {
 						tfd.PauseTimer()
 					}
 				} else {
-					if tfd, ok := file.FileOperations.(*timerfd.TimerOperations); ok {
+					if tfd, ok := file.FileOperations.(*oldtimerfd.TimerOperations); ok {
 						tfd.PauseTimer()
 					}
 				}
@@ -1104,11 +1105,11 @@ func (k *Kernel) resumeTimeLocked() {
 		if t.fdTable != nil {
 			t.fdTable.forEach(func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) {
 				if VFS2Enabled {
-					if tfd, ok := fd.Impl().(*vfs.TimerFileDescription); ok {
+					if tfd, ok := fd.Impl().(*timerfd.TimerFileDescription); ok {
 						tfd.ResumeTimer()
 					}
 				} else {
-					if tfd, ok := file.FileOperations.(*timerfd.TimerOperations); ok {
+					if tfd, ok := file.FileOperations.(*oldtimerfd.TimerOperations); ok {
 						tfd.ResumeTimer()
 					}
 				}
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD
index 14838aa2c..c32f942fb 100644
--- a/pkg/sentry/syscalls/linux/vfs2/BUILD
+++ b/pkg/sentry/syscalls/linux/vfs2/BUILD
@@ -39,8 +39,10 @@ go_library(
         "//pkg/gohacks",
         "//pkg/sentry/arch",
         "//pkg/sentry/fsbridge",
+        "//pkg/sentry/fsimpl/eventfd",
         "//pkg/sentry/fsimpl/pipefs",
         "//pkg/sentry/fsimpl/signalfd",
+        "//pkg/sentry/fsimpl/timerfd",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/kernel/pipe",
diff --git a/pkg/sentry/syscalls/linux/vfs2/eventfd.go b/pkg/sentry/syscalls/linux/vfs2/eventfd.go
index bd2194972..aff1a2070 100644
--- a/pkg/sentry/syscalls/linux/vfs2/eventfd.go
+++ b/pkg/sentry/syscalls/linux/vfs2/eventfd.go
@@ -17,6 +17,7 @@ package vfs2
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/eventfd"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
@@ -31,12 +32,13 @@ func Eventfd2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 		return 0, nil, syserror.EINVAL
 	}
 
+	vfsObj := t.Kernel().VFS()
 	fileFlags := uint32(linux.O_RDWR)
 	if flags&linux.EFD_NONBLOCK != 0 {
 		fileFlags |= linux.O_NONBLOCK
 	}
 	semMode := flags&linux.EFD_SEMAPHORE != 0
-	eventfd, err := t.Kernel().VFS().NewEventFD(initVal, semMode, fileFlags)
+	eventfd, err := eventfd.New(vfsObj, initVal, semMode, fileFlags)
 	if err != nil {
 		return 0, nil, err
 	}
diff --git a/pkg/sentry/syscalls/linux/vfs2/timerfd.go b/pkg/sentry/syscalls/linux/vfs2/timerfd.go
index 839a07db1..5ac79bc09 100644
--- a/pkg/sentry/syscalls/linux/vfs2/timerfd.go
+++ b/pkg/sentry/syscalls/linux/vfs2/timerfd.go
@@ -17,9 +17,9 @@ package vfs2
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/timerfd"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
@@ -32,9 +32,12 @@ func TimerfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel
 		return 0, nil, syserror.EINVAL
 	}
 
-	var fileFlags uint32
+	// Timerfds aren't writable per se (their implementation of Write just
+	// returns EINVAL), but they are "opened for writing", which is necessary
+	// to actually reach said implementation of Write.
+	fileFlags := uint32(linux.O_RDWR)
 	if flags&linux.TFD_NONBLOCK != 0 {
-		fileFlags = linux.O_NONBLOCK
+		fileFlags |= linux.O_NONBLOCK
 	}
 
 	var clock ktime.Clock
@@ -46,10 +49,8 @@ func TimerfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel
 	default:
 		return 0, nil, syserror.EINVAL
 	}
-	// Timerfds aren't writable per se (their implementation of Write just
-	// returns EINVAL), but they are "opened for writing", which is necessary
-	// to actually reach said implementation of Write.
-	file, err := t.Kernel().VFS().NewTimerFD(clock, linux.O_RDWR|fileFlags)
+	vfsObj := t.Kernel().VFS()
+	file, err := timerfd.New(vfsObj, clock, fileFlags)
 	if err != nil {
 		return 0, nil, err
 	}
@@ -80,7 +81,7 @@ func TimerfdSettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne
 	}
 	defer file.DecRef()
 
-	tfd, ok := file.Impl().(*vfs.TimerFileDescription)
+	tfd, ok := file.Impl().(*timerfd.TimerFileDescription)
 	if !ok {
 		return 0, nil, syserror.EINVAL
 	}
@@ -114,7 +115,7 @@ func TimerfdGettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne
 	}
 	defer file.DecRef()
 
-	tfd, ok := file.Impl().(*vfs.TimerFileDescription)
+	tfd, ok := file.Impl().(*timerfd.TimerFileDescription)
 	if !ok {
 		return 0, nil, syserror.EINVAL
 	}
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index 86046dd99..94d69c1cc 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -25,7 +25,6 @@ go_library(
         "device.go",
         "epoll.go",
         "epoll_interest_list.go",
-        "eventfd.go",
         "file_description.go",
         "file_description_impl_util.go",
         "filesystem.go",
@@ -37,7 +36,6 @@ go_library(
         "pathname.go",
         "permissions.go",
         "resolving_path.go",
-        "timerfd.go",
         "vfs.go",
     ],
     visibility = ["//pkg/sentry:internal"],
@@ -71,7 +69,6 @@ go_test(
     name = "vfs_test",
     size = "small",
     srcs = [
-        "eventfd_test.go",
         "file_description_impl_util_test.go",
         "mount_test.go",
     ],
@@ -83,6 +80,5 @@ go_test(
         "//pkg/sync",
         "//pkg/syserror",
         "//pkg/usermem",
-        "//pkg/waiter",
     ],
 )