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-rw-r--r--pkg/sentry/arch/signal.go23
-rw-r--r--pkg/sentry/fsimpl/overlay/regular_file.go4
-rw-r--r--pkg/sentry/kernel/epoll/epoll.go7
-rw-r--r--pkg/sentry/kernel/fasync/BUILD2
-rw-r--r--pkg/sentry/kernel/fasync/fasync.go96
-rw-r--r--pkg/sentry/syscalls/linux/sys_file.go16
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/fd.go18
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/ioctl.go2
-rw-r--r--pkg/sentry/vfs/epoll.go10
-rw-r--r--pkg/sentry/vfs/file_description.go9
-rw-r--r--pkg/sentry/vfs/save_restore.go19
11 files changed, 169 insertions, 37 deletions
diff --git a/pkg/sentry/arch/signal.go b/pkg/sentry/arch/signal.go
index c9fb55d00..5138f3bf5 100644
--- a/pkg/sentry/arch/signal.go
+++ b/pkg/sentry/arch/signal.go
@@ -251,3 +251,26 @@ func (s *SignalInfo) Arch() uint32 {
func (s *SignalInfo) SetArch(val uint32) {
usermem.ByteOrder.PutUint32(s.Fields[12:16], val)
}
+
+// Band returns the si_band field.
+func (s *SignalInfo) Band() int64 {
+ return int64(usermem.ByteOrder.Uint64(s.Fields[0:8]))
+}
+
+// SetBand mutates the si_band field.
+func (s *SignalInfo) SetBand(val int64) {
+ // Note: this assumes the platform uses `long` as `__ARCH_SI_BAND_T`.
+ // On some platforms, which gVisor doesn't support, `__ARCH_SI_BAND_T` is
+ // `int`. See siginfo.h.
+ usermem.ByteOrder.PutUint64(s.Fields[0:8], uint64(val))
+}
+
+// FD returns the si_fd field.
+func (s *SignalInfo) FD() uint32 {
+ return usermem.ByteOrder.Uint32(s.Fields[8:12])
+}
+
+// SetFD mutates the si_fd field.
+func (s *SignalInfo) SetFD(val uint32) {
+ usermem.ByteOrder.PutUint32(s.Fields[8:12], val)
+}
diff --git a/pkg/sentry/fsimpl/overlay/regular_file.go b/pkg/sentry/fsimpl/overlay/regular_file.go
index 2b89a7a6d..25c785fd4 100644
--- a/pkg/sentry/fsimpl/overlay/regular_file.go
+++ b/pkg/sentry/fsimpl/overlay/regular_file.go
@@ -103,8 +103,8 @@ func (fd *regularFileFD) currentFDLocked(ctx context.Context) (*vfs.FileDescript
for e, mask := range fd.lowerWaiters {
fd.cachedFD.EventUnregister(e)
upperFD.EventRegister(e, mask)
- if ready&mask != 0 {
- e.Callback.Callback(e)
+ if m := ready & mask; m != 0 {
+ e.Callback.Callback(e, m)
}
}
}
diff --git a/pkg/sentry/kernel/epoll/epoll.go b/pkg/sentry/kernel/epoll/epoll.go
index 15519f0df..61aeca044 100644
--- a/pkg/sentry/kernel/epoll/epoll.go
+++ b/pkg/sentry/kernel/epoll/epoll.go
@@ -273,7 +273,7 @@ func (e *EventPoll) ReadEvents(max int) []linux.EpollEvent {
//
// Callback is called when one of the files we're polling becomes ready. It
// moves said file to the readyList if it's currently in the waiting list.
-func (p *pollEntry) Callback(*waiter.Entry) {
+func (p *pollEntry) Callback(*waiter.Entry, waiter.EventMask) {
e := p.epoll
e.listsMu.Lock()
@@ -306,9 +306,8 @@ func (e *EventPoll) initEntryReadiness(entry *pollEntry) {
f.EventRegister(&entry.waiter, entry.mask)
// Check if the file happens to already be in a ready state.
- ready := f.Readiness(entry.mask) & entry.mask
- if ready != 0 {
- entry.Callback(&entry.waiter)
+ if ready := f.Readiness(entry.mask) & entry.mask; ready != 0 {
+ entry.Callback(&entry.waiter, ready)
}
}
diff --git a/pkg/sentry/kernel/fasync/BUILD b/pkg/sentry/kernel/fasync/BUILD
index 2b3955598..f855f038b 100644
--- a/pkg/sentry/kernel/fasync/BUILD
+++ b/pkg/sentry/kernel/fasync/BUILD
@@ -8,11 +8,13 @@ go_library(
visibility = ["//:sandbox"],
deps = [
"//pkg/abi/linux",
+ "//pkg/sentry/arch",
"//pkg/sentry/fs",
"//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/vfs",
"//pkg/sync",
+ "//pkg/syserror",
"//pkg/waiter",
],
)
diff --git a/pkg/sentry/kernel/fasync/fasync.go b/pkg/sentry/kernel/fasync/fasync.go
index 153d2cd9b..b66d61c6f 100644
--- a/pkg/sentry/kernel/fasync/fasync.go
+++ b/pkg/sentry/kernel/fasync/fasync.go
@@ -17,22 +17,45 @@ package fasync
import (
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/waiter"
)
-// New creates a new fs.FileAsync.
-func New() fs.FileAsync {
- return &FileAsync{}
+// Table to convert waiter event masks into si_band siginfo codes.
+// Taken from fs/fcntl.c:band_table.
+var bandTable = map[waiter.EventMask]int64{
+ // POLL_IN
+ waiter.EventIn: linux.EPOLLIN | linux.EPOLLRDNORM,
+ // POLL_OUT
+ waiter.EventOut: linux.EPOLLOUT | linux.EPOLLWRNORM | linux.EPOLLWRBAND,
+ // POLL_ERR
+ waiter.EventErr: linux.EPOLLERR,
+ // POLL_PRI
+ waiter.EventPri: linux.EPOLLPRI | linux.EPOLLRDBAND,
+ // POLL_HUP
+ waiter.EventHUp: linux.EPOLLHUP | linux.EPOLLERR,
}
-// NewVFS2 creates a new vfs.FileAsync.
-func NewVFS2() vfs.FileAsync {
- return &FileAsync{}
+// New returns a function that creates a new fs.FileAsync with the given file
+// descriptor.
+func New(fd int) func() fs.FileAsync {
+ return func() fs.FileAsync {
+ return &FileAsync{fd: fd}
+ }
+}
+
+// NewVFS2 returns a function that creates a new vfs.FileAsync with the given
+// file descriptor.
+func NewVFS2(fd int) func() vfs.FileAsync {
+ return func() vfs.FileAsync {
+ return &FileAsync{fd: fd}
+ }
}
// FileAsync sends signals when the registered file is ready for IO.
@@ -42,6 +65,12 @@ type FileAsync struct {
// e is immutable after first use (which is protected by mu below).
e waiter.Entry
+ // fd is the file descriptor to notify about.
+ // It is immutable, set at allocation time. This matches Linux semantics in
+ // fs/fcntl.c:fasync_helper.
+ // The fd value is passed to the signal recipient in siginfo.si_fd.
+ fd int
+
// regMu protects registeration and unregistration actions on e.
//
// regMu must be held while registration decisions are being made
@@ -56,6 +85,10 @@ type FileAsync struct {
mu sync.Mutex `state:"nosave"`
requester *auth.Credentials
registered bool
+ // signal is the signal to deliver upon I/O being available.
+ // The default value ("zero signal") means the default SIGIO signal will be
+ // delivered.
+ signal linux.Signal
// Only one of the following is allowed to be non-nil.
recipientPG *kernel.ProcessGroup
@@ -64,10 +97,10 @@ type FileAsync struct {
}
// Callback sends a signal.
-func (a *FileAsync) Callback(e *waiter.Entry) {
+func (a *FileAsync) Callback(e *waiter.Entry, mask waiter.EventMask) {
a.mu.Lock()
+ defer a.mu.Unlock()
if !a.registered {
- a.mu.Unlock()
return
}
t := a.recipientT
@@ -80,19 +113,34 @@ func (a *FileAsync) Callback(e *waiter.Entry) {
}
if t == nil {
// No recipient has been registered.
- a.mu.Unlock()
return
}
c := t.Credentials()
// Logic from sigio_perm in fs/fcntl.c.
- if a.requester.EffectiveKUID == 0 ||
+ permCheck := (a.requester.EffectiveKUID == 0 ||
a.requester.EffectiveKUID == c.SavedKUID ||
a.requester.EffectiveKUID == c.RealKUID ||
a.requester.RealKUID == c.SavedKUID ||
- a.requester.RealKUID == c.RealKUID {
- t.SendSignal(kernel.SignalInfoPriv(linux.SIGIO))
+ a.requester.RealKUID == c.RealKUID)
+ if !permCheck {
+ return
}
- a.mu.Unlock()
+ signalInfo := &arch.SignalInfo{
+ Signo: int32(linux.SIGIO),
+ Code: arch.SignalInfoKernel,
+ }
+ if a.signal != 0 {
+ signalInfo.Signo = int32(a.signal)
+ signalInfo.SetFD(uint32(a.fd))
+ var band int64
+ for m, bandCode := range bandTable {
+ if m&mask != 0 {
+ band |= bandCode
+ }
+ }
+ signalInfo.SetBand(band)
+ }
+ t.SendSignal(signalInfo)
}
// Register sets the file which will be monitored for IO events.
@@ -186,3 +234,25 @@ func (a *FileAsync) ClearOwner() {
a.recipientTG = nil
a.recipientPG = nil
}
+
+// Signal returns which signal will be sent to the signal recipient.
+// A value of zero means the signal to deliver wasn't customized, which means
+// the default signal (SIGIO) will be delivered.
+func (a *FileAsync) Signal() linux.Signal {
+ a.mu.Lock()
+ defer a.mu.Unlock()
+ return a.signal
+}
+
+// SetSignal overrides which signal to send when I/O is available.
+// The default behavior can be reset by specifying signal zero, which means
+// to send SIGIO.
+func (a *FileAsync) SetSignal(signal linux.Signal) error {
+ if signal != 0 && !signal.IsValid() {
+ return syserror.EINVAL
+ }
+ a.mu.Lock()
+ defer a.mu.Unlock()
+ a.signal = signal
+ return nil
+}
diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index 519066a47..8db587401 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -646,7 +646,7 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
if _, err := primitive.CopyInt32In(t, args[2].Pointer(), &set); err != nil {
return 0, nil, err
}
- fSetOwn(t, file, set)
+ fSetOwn(t, int(fd), file, set)
return 0, nil, nil
case linux.FIOGETOWN, linux.SIOCGPGRP:
@@ -901,8 +901,8 @@ func fGetOwn(t *kernel.Task, file *fs.File) int32 {
//
// If who is positive, it represents a PID. If negative, it represents a PGID.
// If the PID or PGID is invalid, the owner is silently unset.
-func fSetOwn(t *kernel.Task, file *fs.File, who int32) error {
- a := file.Async(fasync.New).(*fasync.FileAsync)
+func fSetOwn(t *kernel.Task, fd int, file *fs.File, who int32) error {
+ a := file.Async(fasync.New(fd)).(*fasync.FileAsync)
if who < 0 {
// Check for overflow before flipping the sign.
if who-1 > who {
@@ -1049,7 +1049,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
case linux.F_GETOWN:
return uintptr(fGetOwn(t, file)), nil, nil
case linux.F_SETOWN:
- return 0, nil, fSetOwn(t, file, args[2].Int())
+ return 0, nil, fSetOwn(t, int(fd), file, args[2].Int())
case linux.F_GETOWN_EX:
addr := args[2].Pointer()
owner := fGetOwnEx(t, file)
@@ -1062,7 +1062,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
if err != nil {
return 0, nil, err
}
- a := file.Async(fasync.New).(*fasync.FileAsync)
+ a := file.Async(fasync.New(int(fd))).(*fasync.FileAsync)
switch owner.Type {
case linux.F_OWNER_TID:
task := t.PIDNamespace().TaskWithID(kernel.ThreadID(owner.PID))
@@ -1111,6 +1111,12 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
}
n, err := sz.SetFifoSize(int64(args[2].Int()))
return uintptr(n), nil, err
+ case linux.F_GETSIG:
+ a := file.Async(fasync.New(int(fd))).(*fasync.FileAsync)
+ return uintptr(a.Signal()), nil, nil
+ case linux.F_SETSIG:
+ a := file.Async(fasync.New(int(fd))).(*fasync.FileAsync)
+ return 0, nil, a.SetSignal(linux.Signal(args[2].Int()))
default:
// Everything else is not yet supported.
return 0, nil, syserror.EINVAL
diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go
index 36e89700e..7dd9ef857 100644
--- a/pkg/sentry/syscalls/linux/vfs2/fd.go
+++ b/pkg/sentry/syscalls/linux/vfs2/fd.go
@@ -165,7 +165,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
ownerType = linux.F_OWNER_PGRP
who = -who
}
- return 0, nil, setAsyncOwner(t, file, ownerType, who)
+ return 0, nil, setAsyncOwner(t, int(fd), file, ownerType, who)
case linux.F_GETOWN_EX:
owner, hasOwner := getAsyncOwner(t, file)
if !hasOwner {
@@ -179,7 +179,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
if err != nil {
return 0, nil, err
}
- return 0, nil, setAsyncOwner(t, file, owner.Type, owner.PID)
+ return 0, nil, setAsyncOwner(t, int(fd), file, owner.Type, owner.PID)
case linux.F_SETPIPE_SZ:
pipefile, ok := file.Impl().(*pipe.VFSPipeFD)
if !ok {
@@ -207,6 +207,16 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
return 0, nil, err
case linux.F_SETLK, linux.F_SETLKW:
return 0, nil, posixLock(t, args, file, cmd)
+ case linux.F_GETSIG:
+ a := file.AsyncHandler()
+ if a == nil {
+ // Default behavior aka SIGIO.
+ return 0, nil, nil
+ }
+ return uintptr(a.(*fasync.FileAsync).Signal()), nil, nil
+ case linux.F_SETSIG:
+ a := file.SetAsyncHandler(fasync.NewVFS2(int(fd))).(*fasync.FileAsync)
+ return 0, nil, a.SetSignal(linux.Signal(args[2].Int()))
default:
// Everything else is not yet supported.
return 0, nil, syserror.EINVAL
@@ -241,7 +251,7 @@ func getAsyncOwner(t *kernel.Task, fd *vfs.FileDescription) (ownerEx linux.FOwne
}
}
-func setAsyncOwner(t *kernel.Task, fd *vfs.FileDescription, ownerType, pid int32) error {
+func setAsyncOwner(t *kernel.Task, fd int, file *vfs.FileDescription, ownerType, pid int32) error {
switch ownerType {
case linux.F_OWNER_TID, linux.F_OWNER_PID, linux.F_OWNER_PGRP:
// Acceptable type.
@@ -249,7 +259,7 @@ func setAsyncOwner(t *kernel.Task, fd *vfs.FileDescription, ownerType, pid int32
return syserror.EINVAL
}
- a := fd.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync)
+ a := file.SetAsyncHandler(fasync.NewVFS2(fd)).(*fasync.FileAsync)
if pid == 0 {
a.ClearOwner()
return nil
diff --git a/pkg/sentry/syscalls/linux/vfs2/ioctl.go b/pkg/sentry/syscalls/linux/vfs2/ioctl.go
index 2806c3f6f..20c264fef 100644
--- a/pkg/sentry/syscalls/linux/vfs2/ioctl.go
+++ b/pkg/sentry/syscalls/linux/vfs2/ioctl.go
@@ -100,7 +100,7 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
ownerType = linux.F_OWNER_PGRP
who = -who
}
- return 0, nil, setAsyncOwner(t, file, ownerType, who)
+ return 0, nil, setAsyncOwner(t, int(fd), file, ownerType, who)
}
ret, err := file.Ioctl(t, t.MemoryManager(), args)
diff --git a/pkg/sentry/vfs/epoll.go b/pkg/sentry/vfs/epoll.go
index a98aac52b..072655fe8 100644
--- a/pkg/sentry/vfs/epoll.go
+++ b/pkg/sentry/vfs/epoll.go
@@ -204,8 +204,8 @@ func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, event lin
file.EventRegister(&epi.waiter, wmask)
// Check if the file is already ready.
- if file.Readiness(wmask)&wmask != 0 {
- epi.Callback(nil)
+ if m := file.Readiness(wmask) & wmask; m != 0 {
+ epi.Callback(nil, m)
}
// Add epi to file.epolls so that it is removed when the last
@@ -274,8 +274,8 @@ func (ep *EpollInstance) ModifyInterest(file *FileDescription, num int32, event
file.EventRegister(&epi.waiter, wmask)
// Check if the file is already ready with the new mask.
- if file.Readiness(wmask)&wmask != 0 {
- epi.Callback(nil)
+ if m := file.Readiness(wmask) & wmask; m != 0 {
+ epi.Callback(nil, m)
}
return nil
@@ -311,7 +311,7 @@ func (ep *EpollInstance) DeleteInterest(file *FileDescription, num int32) error
}
// Callback implements waiter.EntryCallback.Callback.
-func (epi *epollInterest) Callback(*waiter.Entry) {
+func (epi *epollInterest) Callback(*waiter.Entry, waiter.EventMask) {
newReady := false
epi.epoll.mu.Lock()
if !epi.ready {
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index 51fddbaff..2153382e9 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -43,7 +43,7 @@ import (
type FileDescription struct {
FileDescriptionRefs
- // flagsMu protects statusFlags and asyncHandler below.
+ // flagsMu protects `statusFlags`, `saved`, and `asyncHandler` below.
flagsMu sync.Mutex `state:"nosave"`
// statusFlags contains status flags, "initialized by open(2) and possibly
@@ -52,6 +52,11 @@ type FileDescription struct {
// access to asyncHandler.
statusFlags uint32
+ // saved is true after beforeSave is called. This is used to prevent
+ // double-unregistration of asyncHandler. This does not work properly for
+ // save-resume, which is not currently supported in gVisor (see b/26588733).
+ saved bool `state:"nosave"`
+
// asyncHandler handles O_ASYNC signal generation. It is set with the
// F_SETOWN or F_SETOWN_EX fcntls. For asyncHandler to be used, O_ASYNC must
// also be set by fcntl(2).
@@ -184,7 +189,7 @@ func (fd *FileDescription) DecRef(ctx context.Context) {
}
fd.vd.DecRef(ctx)
fd.flagsMu.Lock()
- if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil {
+ if !fd.saved && fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil {
fd.asyncHandler.Unregister(fd)
}
fd.asyncHandler = nil
diff --git a/pkg/sentry/vfs/save_restore.go b/pkg/sentry/vfs/save_restore.go
index 7723ed643..8f070ed53 100644
--- a/pkg/sentry/vfs/save_restore.go
+++ b/pkg/sentry/vfs/save_restore.go
@@ -18,8 +18,10 @@ import (
"fmt"
"sync/atomic"
+ "gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/refsvfs2"
+ "gvisor.dev/gvisor/pkg/waiter"
)
// FilesystemImplSaveRestoreExtension is an optional extension to
@@ -120,5 +122,20 @@ func (mnt *Mount) afterLoad() {
func (epi *epollInterest) afterLoad() {
// Mark all epollInterests as ready after restore so that the next call to
// EpollInstance.ReadEvents() rechecks their readiness.
- epi.Callback(nil)
+ epi.Callback(nil, waiter.EventMaskFromLinux(epi.mask))
+}
+
+// beforeSave is called by stateify.
+func (fd *FileDescription) beforeSave() {
+ fd.saved = true
+ if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil {
+ fd.asyncHandler.Unregister(fd)
+ }
+}
+
+// afterLoad is called by stateify.
+func (fd *FileDescription) afterLoad() {
+ if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil {
+ fd.asyncHandler.Register(fd)
+ }
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 17:40:34 +0000