summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'pkg/sentry/kernel')
-rw-r--r--pkg/sentry/kernel/BUILD5
-rw-r--r--pkg/sentry/kernel/kcov.go38
-rw-r--r--pkg/sentry/kernel/kernel.go96
-rw-r--r--pkg/sentry/kernel/pipe/BUILD1
-rw-r--r--pkg/sentry/kernel/pipe/pipe.go3
-rw-r--r--pkg/sentry/kernel/pipe/pipe_util.go12
-rw-r--r--pkg/sentry/kernel/pipe/vfs.go5
-rw-r--r--pkg/sentry/kernel/seccomp.go46
-rw-r--r--pkg/sentry/kernel/signalfd/BUILD1
-rw-r--r--pkg/sentry/kernel/signalfd/signalfd.go14
-rw-r--r--pkg/sentry/kernel/task.go2
-rw-r--r--pkg/sentry/kernel/task_context.go6
-rw-r--r--pkg/sentry/kernel/task_signals.go6
-rw-r--r--pkg/sentry/kernel/vdso.go19
14 files changed, 167 insertions, 87 deletions
diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index a43c549f1..5de70aecb 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -69,8 +69,8 @@ go_template_instance(
prefix = "socket",
template = "//pkg/ilist:generic_list",
types = {
- "Element": "*SocketEntry",
- "Linker": "*SocketEntry",
+ "Element": "*SocketRecordVFS1",
+ "Linker": "*SocketRecordVFS1",
},
)
@@ -204,7 +204,6 @@ go_library(
"//pkg/abi",
"//pkg/abi/linux",
"//pkg/amutex",
- "//pkg/binary",
"//pkg/bits",
"//pkg/bpf",
"//pkg/context",
diff --git a/pkg/sentry/kernel/kcov.go b/pkg/sentry/kernel/kcov.go
index aad63aa99..90ceb5ef5 100644
--- a/pkg/sentry/kernel/kcov.go
+++ b/pkg/sentry/kernel/kcov.go
@@ -89,6 +89,10 @@ func (kcov *Kcov) TaskWork(t *Task) {
kcov.mu.Lock()
defer kcov.mu.Unlock()
+ if kcov.mode != linux.KCOV_MODE_TRACE_PC {
+ return
+ }
+
rw := &kcovReadWriter{
mf: kcov.mfp.MemoryFile(),
fr: kcov.mappable.FileRange(),
@@ -142,7 +146,7 @@ func (kcov *Kcov) InitTrace(size uint64) error {
}
// EnableTrace performs the KCOV_ENABLE_TRACE ioctl.
-func (kcov *Kcov) EnableTrace(ctx context.Context, traceMode uint8) error {
+func (kcov *Kcov) EnableTrace(ctx context.Context, traceKind uint8) error {
t := TaskFromContext(ctx)
if t == nil {
panic("kcovInode.EnableTrace() cannot be used outside of a task goroutine")
@@ -156,9 +160,9 @@ func (kcov *Kcov) EnableTrace(ctx context.Context, traceMode uint8) error {
return syserror.EINVAL
}
- switch traceMode {
+ switch traceKind {
case linux.KCOV_TRACE_PC:
- kcov.mode = traceMode
+ kcov.mode = linux.KCOV_MODE_TRACE_PC
case linux.KCOV_TRACE_CMP:
// We do not support KCOV_MODE_TRACE_CMP.
return syserror.ENOTSUP
@@ -171,6 +175,7 @@ func (kcov *Kcov) EnableTrace(ctx context.Context, traceMode uint8) error {
}
kcov.owningTask = t
+ t.SetKcov(kcov)
t.RegisterWork(kcov)
// Clear existing coverage data; the task expects to read only coverage data
@@ -192,28 +197,39 @@ func (kcov *Kcov) DisableTrace(ctx context.Context) error {
if t != kcov.owningTask {
return syserror.EINVAL
}
- kcov.owningTask = nil
kcov.mode = linux.KCOV_MODE_INIT
- kcov.resetLocked()
+ kcov.owningTask = nil
+ kcov.mappable = nil
return nil
}
-// Reset is called when the owning task exits.
-func (kcov *Kcov) Reset() {
+// Clear resets the mode and clears the owning task and memory mapping for kcov.
+// It is called when the fd corresponding to kcov is closed. Note that the mode
+// needs to be set so that the next call to kcov.TaskWork() will exit early.
+func (kcov *Kcov) Clear() {
kcov.mu.Lock()
- kcov.resetLocked()
+ kcov.clearLocked()
kcov.mu.Unlock()
}
-// The kcov instance is reset when the owning task exits or when tracing is
-// disabled.
-func (kcov *Kcov) resetLocked() {
+func (kcov *Kcov) clearLocked() {
+ kcov.mode = linux.KCOV_MODE_INIT
kcov.owningTask = nil
if kcov.mappable != nil {
kcov.mappable = nil
}
}
+// OnTaskExit is called when the owning task exits. It is similar to
+// kcov.Clear(), except the memory mapping is not cleared, so that the same
+// mapping can be used in the future if kcov is enabled again by another task.
+func (kcov *Kcov) OnTaskExit() {
+ kcov.mu.Lock()
+ kcov.mode = linux.KCOV_MODE_INIT
+ kcov.owningTask = nil
+ kcov.mu.Unlock()
+}
+
// ConfigureMMap is called by the vfs.FileDescription for this kcov instance to
// implement vfs.FileDescription.ConfigureMMap.
func (kcov *Kcov) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 22f9bb006..d6c21adb7 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -220,13 +220,18 @@ type Kernel struct {
// danglingEndpoints is used to save / restore tcpip.DanglingEndpoints.
danglingEndpoints struct{} `state:".([]tcpip.Endpoint)"`
- // sockets is the list of all network sockets the system. Protected by
- // extMu.
+ // sockets is the list of all network sockets in the system.
+ // Protected by extMu.
+ // TODO(gvisor.dev/issue/1624): Only used by VFS1.
sockets socketList
- // nextSocketEntry is the next entry number to use in sockets. Protected
+ // socketsVFS2 records all network sockets in the system. Protected by
+ // extMu.
+ socketsVFS2 map[*vfs.FileDescription]*SocketRecord
+
+ // nextSocketRecord is the next entry number to use in sockets. Protected
// by extMu.
- nextSocketEntry uint64
+ nextSocketRecord uint64
// deviceRegistry is used to save/restore device.SimpleDevices.
deviceRegistry struct{} `state:".(*device.Registry)"`
@@ -414,6 +419,8 @@ func (k *Kernel) Init(args InitKernelArgs) error {
return fmt.Errorf("failed to create sockfs mount: %v", err)
}
k.socketMount = socketMount
+
+ k.socketsVFS2 = make(map[*vfs.FileDescription]*SocketRecord)
}
return nil
@@ -507,6 +514,10 @@ func (k *Kernel) SaveTo(w wire.Writer) error {
// flushMountSourceRefs flushes the MountSources for all mounted filesystems
// and open FDs.
func (k *Kernel) flushMountSourceRefs(ctx context.Context) error {
+ if VFS2Enabled {
+ return nil // Not relevant.
+ }
+
// Flush all mount sources for currently mounted filesystems in each task.
flushed := make(map[*fs.MountNamespace]struct{})
k.tasks.mu.RLock()
@@ -533,11 +544,6 @@ func (k *Kernel) flushMountSourceRefs(ctx context.Context) error {
//
// Precondition: Must be called with the kernel paused.
func (ts *TaskSet) forEachFDPaused(ctx context.Context, f func(*fs.File, *vfs.FileDescription) error) (err error) {
- // TODO(gvisor.dev/issue/1663): Add save support for VFS2.
- if VFS2Enabled {
- return nil
- }
-
ts.mu.RLock()
defer ts.mu.RUnlock()
for t := range ts.Root.tids {
@@ -556,6 +562,10 @@ func (ts *TaskSet) forEachFDPaused(ctx context.Context, f func(*fs.File, *vfs.Fi
func (ts *TaskSet) flushWritesToFiles(ctx context.Context) error {
// TODO(gvisor.dev/issue/1663): Add save support for VFS2.
+ if VFS2Enabled {
+ return nil
+ }
+
return ts.forEachFDPaused(ctx, func(file *fs.File, _ *vfs.FileDescription) error {
if flags := file.Flags(); !flags.Write {
return nil
@@ -1509,20 +1519,27 @@ func (k *Kernel) SupervisorContext() context.Context {
}
}
-// SocketEntry represents a socket recorded in Kernel.sockets. It implements
+// SocketRecord represents a socket recorded in Kernel.socketsVFS2.
+//
+// +stateify savable
+type SocketRecord struct {
+ k *Kernel
+ Sock *refs.WeakRef // TODO(gvisor.dev/issue/1624): Only used by VFS1.
+ SockVFS2 *vfs.FileDescription // Only used by VFS2.
+ ID uint64 // Socket table entry number.
+}
+
+// SocketRecordVFS1 represents a socket recorded in Kernel.sockets. It implements
// refs.WeakRefUser for sockets stored in the socket table.
//
// +stateify savable
-type SocketEntry struct {
+type SocketRecordVFS1 struct {
socketEntry
- k *Kernel
- Sock *refs.WeakRef
- SockVFS2 *vfs.FileDescription
- ID uint64 // Socket table entry number.
+ SocketRecord
}
// WeakRefGone implements refs.WeakRefUser.WeakRefGone.
-func (s *SocketEntry) WeakRefGone(context.Context) {
+func (s *SocketRecordVFS1) WeakRefGone(context.Context) {
s.k.extMu.Lock()
s.k.sockets.Remove(s)
s.k.extMu.Unlock()
@@ -1533,9 +1550,14 @@ func (s *SocketEntry) WeakRefGone(context.Context) {
// Precondition: Caller must hold a reference to sock.
func (k *Kernel) RecordSocket(sock *fs.File) {
k.extMu.Lock()
- id := k.nextSocketEntry
- k.nextSocketEntry++
- s := &SocketEntry{k: k, ID: id}
+ id := k.nextSocketRecord
+ k.nextSocketRecord++
+ s := &SocketRecordVFS1{
+ SocketRecord: SocketRecord{
+ k: k,
+ ID: id,
+ },
+ }
s.Sock = refs.NewWeakRef(sock, s)
k.sockets.PushBack(s)
k.extMu.Unlock()
@@ -1547,29 +1569,45 @@ func (k *Kernel) RecordSocket(sock *fs.File) {
// Precondition: Caller must hold a reference to sock.
//
// Note that the socket table will not hold a reference on the
-// vfs.FileDescription, because we do not support weak refs on VFS2 files.
+// vfs.FileDescription.
func (k *Kernel) RecordSocketVFS2(sock *vfs.FileDescription) {
k.extMu.Lock()
- id := k.nextSocketEntry
- k.nextSocketEntry++
- s := &SocketEntry{
+ if _, ok := k.socketsVFS2[sock]; ok {
+ panic(fmt.Sprintf("Socket %p added twice", sock))
+ }
+ id := k.nextSocketRecord
+ k.nextSocketRecord++
+ s := &SocketRecord{
k: k,
ID: id,
SockVFS2: sock,
}
- k.sockets.PushBack(s)
+ k.socketsVFS2[sock] = s
+ k.extMu.Unlock()
+}
+
+// DeleteSocketVFS2 removes a VFS2 socket from the system-wide socket table.
+func (k *Kernel) DeleteSocketVFS2(sock *vfs.FileDescription) {
+ k.extMu.Lock()
+ delete(k.socketsVFS2, sock)
k.extMu.Unlock()
}
// ListSockets returns a snapshot of all sockets.
//
-// Callers of ListSockets() in VFS2 should use SocketEntry.SockVFS2.TryIncRef()
+// Callers of ListSockets() in VFS2 should use SocketRecord.SockVFS2.TryIncRef()
// to get a reference on a socket in the table.
-func (k *Kernel) ListSockets() []*SocketEntry {
+func (k *Kernel) ListSockets() []*SocketRecord {
k.extMu.Lock()
- var socks []*SocketEntry
- for s := k.sockets.Front(); s != nil; s = s.Next() {
- socks = append(socks, s)
+ var socks []*SocketRecord
+ if VFS2Enabled {
+ for _, s := range k.socketsVFS2 {
+ socks = append(socks, s)
+ }
+ } else {
+ for s := k.sockets.Front(); s != nil; s = s.Next() {
+ socks = append(socks, &s.SocketRecord)
+ }
}
k.extMu.Unlock()
return socks
diff --git a/pkg/sentry/kernel/pipe/BUILD b/pkg/sentry/kernel/pipe/BUILD
index 449643118..99134e634 100644
--- a/pkg/sentry/kernel/pipe/BUILD
+++ b/pkg/sentry/kernel/pipe/BUILD
@@ -21,6 +21,7 @@ go_library(
"//pkg/amutex",
"//pkg/buffer",
"//pkg/context",
+ "//pkg/marshal/primitive",
"//pkg/safemem",
"//pkg/sentry/arch",
"//pkg/sentry/device",
diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go
index c410c96aa..67beb0ad6 100644
--- a/pkg/sentry/kernel/pipe/pipe.go
+++ b/pkg/sentry/kernel/pipe/pipe.go
@@ -17,6 +17,7 @@ package pipe
import (
"fmt"
+ "io"
"sync/atomic"
"syscall"
@@ -215,7 +216,7 @@ func (p *Pipe) readLocked(ctx context.Context, ops readOps) (int64, error) {
if p.view.Size() == 0 {
if !p.HasWriters() {
// There are no writers, return EOF.
- return 0, nil
+ return 0, io.EOF
}
return 0, syserror.ErrWouldBlock
}
diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go
index 6d58b682f..f665920cb 100644
--- a/pkg/sentry/kernel/pipe/pipe_util.go
+++ b/pkg/sentry/kernel/pipe/pipe_util.go
@@ -23,6 +23,7 @@ import (
"gvisor.dev/gvisor/pkg/amutex"
"gvisor.dev/gvisor/pkg/buffer"
"gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/marshal/primitive"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/usermem"
@@ -145,9 +146,14 @@ func (p *Pipe) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArgume
v = math.MaxInt32 // Silently truncate.
}
// Copy result to userspace.
- _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{
- AddressSpaceActive: true,
- })
+ iocc := primitive.IOCopyContext{
+ IO: io,
+ Ctx: ctx,
+ Opts: usermem.IOOpts{
+ AddressSpaceActive: true,
+ },
+ }
+ _, err := primitive.CopyInt32Out(&iocc, args[2].Pointer(), int32(v))
return 0, err
default:
return 0, syscall.ENOTTY
diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go
index f223d59e1..f61039f5b 100644
--- a/pkg/sentry/kernel/pipe/vfs.go
+++ b/pkg/sentry/kernel/pipe/vfs.go
@@ -67,6 +67,11 @@ func (vp *VFSPipe) ReaderWriterPair(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlag
return vp.newFD(mnt, vfsd, linux.O_RDONLY|statusFlags, locks), vp.newFD(mnt, vfsd, linux.O_WRONLY|statusFlags, locks)
}
+// Allocate implements vfs.FileDescriptionImpl.Allocate.
+func (*VFSPipe) Allocate(context.Context, uint64, uint64, uint64) error {
+ return syserror.ESPIPE
+}
+
// Open opens the pipe represented by vp.
func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32, locks *vfs.FileLocks) (*vfs.FileDescription, error) {
vp.mu.Lock()
diff --git a/pkg/sentry/kernel/seccomp.go b/pkg/sentry/kernel/seccomp.go
index c38c5a40c..387edfa91 100644
--- a/pkg/sentry/kernel/seccomp.go
+++ b/pkg/sentry/kernel/seccomp.go
@@ -18,7 +18,6 @@ import (
"syscall"
"gvisor.dev/gvisor/pkg/abi/linux"
- "gvisor.dev/gvisor/pkg/binary"
"gvisor.dev/gvisor/pkg/bpf"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/syserror"
@@ -27,25 +26,18 @@ import (
const maxSyscallFilterInstructions = 1 << 15
-// seccompData is equivalent to struct seccomp_data, which contains the data
-// passed to seccomp-bpf filters.
-type seccompData struct {
- // nr is the system call number.
- nr int32
-
- // arch is an AUDIT_ARCH_* value indicating the system call convention.
- arch uint32
-
- // instructionPointer is the value of the instruction pointer at the time
- // of the system call.
- instructionPointer uint64
-
- // args contains the first 6 system call arguments.
- args [6]uint64
-}
-
-func (d *seccompData) asBPFInput() bpf.Input {
- return bpf.InputBytes{binary.Marshal(nil, usermem.ByteOrder, d), usermem.ByteOrder}
+// dataAsBPFInput returns a serialized BPF program, only valid on the current task
+// goroutine.
+//
+// Note: this is called for every syscall, which is a very hot path.
+func dataAsBPFInput(t *Task, d *linux.SeccompData) bpf.Input {
+ buf := t.CopyScratchBuffer(d.SizeBytes())
+ d.MarshalUnsafe(buf)
+ return bpf.InputBytes{
+ Data: buf,
+ // Go-marshal always uses the native byte order.
+ Order: usermem.ByteOrder,
+ }
}
func seccompSiginfo(t *Task, errno, sysno int32, ip usermem.Addr) *arch.SignalInfo {
@@ -112,20 +104,20 @@ func (t *Task) checkSeccompSyscall(sysno int32, args arch.SyscallArguments, ip u
}
func (t *Task) evaluateSyscallFilters(sysno int32, args arch.SyscallArguments, ip usermem.Addr) uint32 {
- data := seccompData{
- nr: sysno,
- arch: t.tc.st.AuditNumber,
- instructionPointer: uint64(ip),
+ data := linux.SeccompData{
+ Nr: sysno,
+ Arch: t.tc.st.AuditNumber,
+ InstructionPointer: uint64(ip),
}
// data.args is []uint64 and args is []arch.SyscallArgument (uintptr), so
// we can't do any slicing tricks or even use copy/append here.
for i, arg := range args {
- if i >= len(data.args) {
+ if i >= len(data.Args) {
break
}
- data.args[i] = arg.Uint64()
+ data.Args[i] = arg.Uint64()
}
- input := data.asBPFInput()
+ input := dataAsBPFInput(t, &data)
ret := uint32(linux.SECCOMP_RET_ALLOW)
f := t.syscallFilters.Load()
diff --git a/pkg/sentry/kernel/signalfd/BUILD b/pkg/sentry/kernel/signalfd/BUILD
index 3eb78e91b..76d472292 100644
--- a/pkg/sentry/kernel/signalfd/BUILD
+++ b/pkg/sentry/kernel/signalfd/BUILD
@@ -8,7 +8,6 @@ go_library(
visibility = ["//pkg/sentry:internal"],
deps = [
"//pkg/abi/linux",
- "//pkg/binary",
"//pkg/context",
"//pkg/sentry/fs",
"//pkg/sentry/fs/anon",
diff --git a/pkg/sentry/kernel/signalfd/signalfd.go b/pkg/sentry/kernel/signalfd/signalfd.go
index b07e1c1bd..78f718cfe 100644
--- a/pkg/sentry/kernel/signalfd/signalfd.go
+++ b/pkg/sentry/kernel/signalfd/signalfd.go
@@ -17,7 +17,6 @@ package signalfd
import (
"gvisor.dev/gvisor/pkg/abi/linux"
- "gvisor.dev/gvisor/pkg/binary"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/anon"
@@ -103,8 +102,7 @@ func (s *SignalOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOS
}
// 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,
@@ -113,9 +111,13 @@ func (s *SignalOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOS
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.
diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go
index a436610c9..f796e0fa3 100644
--- a/pkg/sentry/kernel/task.go
+++ b/pkg/sentry/kernel/task.go
@@ -917,7 +917,7 @@ func (t *Task) SetKcov(k *Kcov) {
// ResetKcov clears the kcov instance associated with t.
func (t *Task) ResetKcov() {
if t.kcov != nil {
- t.kcov.Reset()
+ t.kcov.OnTaskExit()
t.kcov = nil
}
}
diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go
index 9fa528384..d1136461a 100644
--- a/pkg/sentry/kernel/task_context.go
+++ b/pkg/sentry/kernel/task_context.go
@@ -126,7 +126,11 @@ func (t *Task) SyscallTable() *SyscallTable {
// Preconditions: The caller must be running on the task goroutine, or t.mu
// must be locked.
func (t *Task) Stack() *arch.Stack {
- return &arch.Stack{t.Arch(), t.MemoryManager(), usermem.Addr(t.Arch().Stack())}
+ return &arch.Stack{
+ Arch: t.Arch(),
+ IO: t.MemoryManager(),
+ Bottom: usermem.Addr(t.Arch().Stack()),
+ }
}
// LoadTaskImage loads a specified file into a new TaskContext.
diff --git a/pkg/sentry/kernel/task_signals.go b/pkg/sentry/kernel/task_signals.go
index feaa38596..ebdb83061 100644
--- a/pkg/sentry/kernel/task_signals.go
+++ b/pkg/sentry/kernel/task_signals.go
@@ -259,7 +259,11 @@ func (t *Task) deliverSignalToHandler(info *arch.SignalInfo, act arch.SignalAct)
// Set up the signal handler. If we have a saved signal mask, the signal
// handler should run with the current mask, but sigreturn should restore
// the saved one.
- st := &arch.Stack{t.Arch(), mm, sp}
+ st := &arch.Stack{
+ Arch: t.Arch(),
+ IO: mm,
+ Bottom: sp,
+ }
mask := t.signalMask
if t.haveSavedSignalMask {
mask = t.savedSignalMask
diff --git a/pkg/sentry/kernel/vdso.go b/pkg/sentry/kernel/vdso.go
index e44a139b3..9bc452e67 100644
--- a/pkg/sentry/kernel/vdso.go
+++ b/pkg/sentry/kernel/vdso.go
@@ -17,7 +17,6 @@ package kernel
import (
"fmt"
- "gvisor.dev/gvisor/pkg/binary"
"gvisor.dev/gvisor/pkg/safemem"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/pgalloc"
@@ -28,6 +27,8 @@ import (
//
// They are exposed to the VDSO via a parameter page managed by VDSOParamPage,
// which also includes a sequence counter.
+//
+// +marshal
type vdsoParams struct {
monotonicReady uint64
monotonicBaseCycles int64
@@ -68,6 +69,13 @@ type VDSOParamPage struct {
// checked in state_test_util tests, causing this field to change across
// save / restore.
seq uint64
+
+ // copyScratchBuffer is a temporary buffer used to marshal the params before
+ // copying it to the real parameter page. The parameter page is typically
+ // updated at a moderate frequency of ~O(seconds) throughout the lifetime of
+ // the sentry, so reusing this buffer is a good tradeoff between memory
+ // usage and the cost of allocation.
+ copyScratchBuffer []byte
}
// NewVDSOParamPage returns a VDSOParamPage.
@@ -79,7 +87,11 @@ type VDSOParamPage struct {
// * VDSOParamPage must be the only writer to fr.
// * mfp.MemoryFile().MapInternal(fr) must return a single safemem.Block.
func NewVDSOParamPage(mfp pgalloc.MemoryFileProvider, fr memmap.FileRange) *VDSOParamPage {
- return &VDSOParamPage{mfp: mfp, fr: fr}
+ return &VDSOParamPage{
+ mfp: mfp,
+ fr: fr,
+ copyScratchBuffer: make([]byte, (*vdsoParams)(nil).SizeBytes()),
+ }
}
// access returns a mapping of the param page.
@@ -133,7 +145,8 @@ func (v *VDSOParamPage) Write(f func() vdsoParams) error {
// Get the new params.
p := f()
- buf := binary.Marshal(nil, usermem.ByteOrder, p)
+ buf := v.copyScratchBuffer[:p.SizeBytes()]
+ p.MarshalUnsafe(buf)
// Skip the sequence counter.
if _, err := safemem.Copy(paramPage.DropFirst(8), safemem.BlockFromSafeSlice(buf)); err != nil {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 10:46:44 +0000