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authorRahat Mahmood <rahat@google.com>2020-04-23 15:47:59 -0700
committergVisor bot <gvisor-bot@google.com>2020-04-23 15:49:05 -0700
commit93dd47146185ec7004f514e23bad9f225f55efb1 (patch)
tree5df4b95a0b57b3592b79103bf91df0a3a50581a2 /pkg/sentry
parent5042ea7e2cbdc0c04fd454583589a3b1e152f95d (diff)
Enable automated marshalling for epoll events.
Ensure we use the correct architecture-specific defintion of epoll event, and use go-marshal for serialization. PiperOrigin-RevId: 308145677
Diffstat (limited to 'pkg/sentry')
-rw-r--r--pkg/sentry/kernel/epoll/BUILD1
-rw-r--r--pkg/sentry/kernel/epoll/epoll.go20
-rw-r--r--pkg/sentry/syscalls/epoll.go3
-rw-r--r--pkg/sentry/syscalls/linux/sys_epoll.go27
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/BUILD1
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/epoll.go7
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/epoll_unsafe.go44
7 files changed, 14 insertions, 89 deletions
diff --git a/pkg/sentry/kernel/epoll/BUILD b/pkg/sentry/kernel/epoll/BUILD
index dedf0fa15..75eedd5a2 100644
--- a/pkg/sentry/kernel/epoll/BUILD
+++ b/pkg/sentry/kernel/epoll/BUILD
@@ -24,6 +24,7 @@ go_library(
],
visibility = ["//pkg/sentry:internal"],
deps = [
+ "//pkg/abi/linux",
"//pkg/context",
"//pkg/refs",
"//pkg/sentry/fs",
diff --git a/pkg/sentry/kernel/epoll/epoll.go b/pkg/sentry/kernel/epoll/epoll.go
index 592650923..3d78cd48f 100644
--- a/pkg/sentry/kernel/epoll/epoll.go
+++ b/pkg/sentry/kernel/epoll/epoll.go
@@ -20,6 +20,7 @@ import (
"fmt"
"syscall"
+ "gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/refs"
"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -30,19 +31,6 @@ import (
"gvisor.dev/gvisor/pkg/waiter"
)
-// Event describes the event mask that was observed and the user data to be
-// returned when one of the events occurs. It has this format to match the linux
-// format to avoid extra copying/allocation when writing events to userspace.
-type Event struct {
- // Events is the event mask containing the set of events that have been
- // observed on an entry.
- Events uint32
-
- // Data is an opaque 64-bit value provided by the caller when adding the
- // entry, and returned to the caller when the entry reports an event.
- Data [2]int32
-}
-
// EntryFlags is a bitmask that holds an entry's flags.
type EntryFlags int
@@ -227,9 +215,9 @@ func (e *EventPoll) Readiness(mask waiter.EventMask) waiter.EventMask {
}
// ReadEvents returns up to max available events.
-func (e *EventPoll) ReadEvents(max int) []Event {
+func (e *EventPoll) ReadEvents(max int) []linux.EpollEvent {
var local pollEntryList
- var ret []Event
+ var ret []linux.EpollEvent
e.listsMu.Lock()
@@ -251,7 +239,7 @@ func (e *EventPoll) ReadEvents(max int) []Event {
}
// Add event to the array that will be returned to caller.
- ret = append(ret, Event{
+ ret = append(ret, linux.EpollEvent{
Events: uint32(ready),
Data: entry.userData,
})
diff --git a/pkg/sentry/syscalls/epoll.go b/pkg/sentry/syscalls/epoll.go
index 87dcad18b..d9fb808c0 100644
--- a/pkg/sentry/syscalls/epoll.go
+++ b/pkg/sentry/syscalls/epoll.go
@@ -17,6 +17,7 @@ package syscalls
import (
"time"
+ "gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/epoll"
ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
@@ -118,7 +119,7 @@ func RemoveEpoll(t *kernel.Task, epfd int32, fd int32) error {
}
// WaitEpoll implements the epoll_wait(2) linux syscall.
-func WaitEpoll(t *kernel.Task, fd int32, max int, timeout int) ([]epoll.Event, error) {
+func WaitEpoll(t *kernel.Task, fd int32, max int, timeout int) ([]linux.EpollEvent, error) {
// Get epoll from the file descriptor.
epollfile := t.GetFile(fd)
if epollfile == nil {
diff --git a/pkg/sentry/syscalls/linux/sys_epoll.go b/pkg/sentry/syscalls/linux/sys_epoll.go
index 3ab93fbde..51bf205cf 100644
--- a/pkg/sentry/syscalls/linux/sys_epoll.go
+++ b/pkg/sentry/syscalls/linux/sys_epoll.go
@@ -21,7 +21,6 @@ import (
"gvisor.dev/gvisor/pkg/sentry/kernel/epoll"
"gvisor.dev/gvisor/pkg/sentry/syscalls"
"gvisor.dev/gvisor/pkg/syserror"
- "gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
@@ -72,7 +71,7 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
var data [2]int32
if op != linux.EPOLL_CTL_DEL {
var e linux.EpollEvent
- if _, err := t.CopyIn(eventAddr, &e); err != nil {
+ if _, err := e.CopyIn(t, eventAddr); err != nil {
return 0, nil, err
}
@@ -105,28 +104,6 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
}
}
-// copyOutEvents copies epoll events from the kernel to user memory.
-func copyOutEvents(t *kernel.Task, addr usermem.Addr, e []epoll.Event) error {
- const itemLen = 12
- buffLen := len(e) * itemLen
- if _, ok := addr.AddLength(uint64(buffLen)); !ok {
- return syserror.EFAULT
- }
-
- b := t.CopyScratchBuffer(buffLen)
- for i := range e {
- usermem.ByteOrder.PutUint32(b[i*itemLen:], e[i].Events)
- usermem.ByteOrder.PutUint32(b[i*itemLen+4:], uint32(e[i].Data[0]))
- usermem.ByteOrder.PutUint32(b[i*itemLen+8:], uint32(e[i].Data[1]))
- }
-
- if _, err := t.CopyOutBytes(addr, b); err != nil {
- return err
- }
-
- return nil
-}
-
// EpollWait implements the epoll_wait(2) linux syscall.
func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
epfd := args[0].Int()
@@ -140,7 +117,7 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
}
if len(r) != 0 {
- if err := copyOutEvents(t, eventsAddr, r); err != nil {
+ if _, err := linux.CopyEpollEventSliceOut(t, eventsAddr, r); err != nil {
return 0, nil, err
}
}
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD
index 6ff2d84d2..f6fb0f219 100644
--- a/pkg/sentry/syscalls/linux/vfs2/BUILD
+++ b/pkg/sentry/syscalls/linux/vfs2/BUILD
@@ -6,7 +6,6 @@ go_library(
name = "vfs2",
srcs = [
"epoll.go",
- "epoll_unsafe.go",
"execve.go",
"fd.go",
"filesystem.go",
diff --git a/pkg/sentry/syscalls/linux/vfs2/epoll.go b/pkg/sentry/syscalls/linux/vfs2/epoll.go
index 5a938cee2..34c90ae3e 100644
--- a/pkg/sentry/syscalls/linux/vfs2/epoll.go
+++ b/pkg/sentry/syscalls/linux/vfs2/epoll.go
@@ -28,6 +28,8 @@ import (
"gvisor.dev/gvisor/pkg/waiter"
)
+var sizeofEpollEvent = (*linux.EpollEvent)(nil).SizeBytes()
+
// EpollCreate1 implements Linux syscall epoll_create1(2).
func EpollCreate1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
flags := args[0].Int()
@@ -124,7 +126,7 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
maxEvents := int(args[2].Int())
timeout := int(args[3].Int())
- const _EP_MAX_EVENTS = math.MaxInt32 / sizeofEpollEvent // Linux: fs/eventpoll.c:EP_MAX_EVENTS
+ var _EP_MAX_EVENTS = math.MaxInt32 / sizeofEpollEvent // Linux: fs/eventpoll.c:EP_MAX_EVENTS
if maxEvents <= 0 || maxEvents > _EP_MAX_EVENTS {
return 0, nil, syserror.EINVAL
}
@@ -157,7 +159,8 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
maxEvents -= n
if n != 0 {
// Copy what we read out.
- copiedEvents, err := copyOutEvents(t, eventsAddr, events[:n])
+ copiedBytes, err := linux.CopyEpollEventSliceOut(t, eventsAddr, events[:n])
+ copiedEvents := copiedBytes / sizeofEpollEvent // rounded down
eventsAddr += usermem.Addr(copiedEvents * sizeofEpollEvent)
total += copiedEvents
if err != nil {
diff --git a/pkg/sentry/syscalls/linux/vfs2/epoll_unsafe.go b/pkg/sentry/syscalls/linux/vfs2/epoll_unsafe.go
deleted file mode 100644
index 825f325bf..000000000
--- a/pkg/sentry/syscalls/linux/vfs2/epoll_unsafe.go
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright 2020 The gVisor Authors.
-//
-// 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 vfs2
-
-import (
- "reflect"
- "runtime"
- "unsafe"
-
- "gvisor.dev/gvisor/pkg/abi/linux"
- "gvisor.dev/gvisor/pkg/gohacks"
- "gvisor.dev/gvisor/pkg/sentry/kernel"
- "gvisor.dev/gvisor/pkg/usermem"
-)
-
-const sizeofEpollEvent = int(unsafe.Sizeof(linux.EpollEvent{}))
-
-func copyOutEvents(t *kernel.Task, addr usermem.Addr, events []linux.EpollEvent) (int, error) {
- if len(events) == 0 {
- return 0, nil
- }
- // Cast events to a byte slice for copying.
- var eventBytes []byte
- eventBytesHdr := (*reflect.SliceHeader)(unsafe.Pointer(&eventBytes))
- eventBytesHdr.Data = uintptr(gohacks.Noescape(unsafe.Pointer(&events[0])))
- eventBytesHdr.Len = len(events) * sizeofEpollEvent
- eventBytesHdr.Cap = len(events) * sizeofEpollEvent
- copiedBytes, err := t.CopyOutBytes(addr, eventBytes)
- runtime.KeepAlive(events)
- copiedEvents := copiedBytes / sizeofEpollEvent // rounded down
- return copiedEvents, err
-}