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-rw-r--r--pkg/sentry/fsimpl/signalfd/BUILD20
-rw-r--r--pkg/sentry/fsimpl/signalfd/signalfd.go135
-rw-r--r--pkg/sentry/syscalls/linux/sigset.go8
-rw-r--r--pkg/sentry/syscalls/linux/sys_epoll.go2
-rw-r--r--pkg/sentry/syscalls/linux/sys_poll.go4
-rw-r--r--pkg/sentry/syscalls/linux/sys_signal.go6
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/BUILD2
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/signal.go100
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/vfs2.go4
-rw-r--r--pkg/sentry/vfs/BUILD1
10 files changed, 272 insertions, 10 deletions
diff --git a/pkg/sentry/fsimpl/signalfd/BUILD b/pkg/sentry/fsimpl/signalfd/BUILD
new file mode 100644
index 000000000..067c1657f
--- /dev/null
+++ b/pkg/sentry/fsimpl/signalfd/BUILD
@@ -0,0 +1,20 @@
+load("//tools:defs.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+ name = "signalfd",
+ srcs = ["signalfd.go"],
+ visibility = ["//pkg/sentry:internal"],
+ deps = [
+ "//pkg/abi/linux",
+ "//pkg/binary",
+ "//pkg/context",
+ "//pkg/sentry/kernel",
+ "//pkg/sentry/vfs",
+ "//pkg/sync",
+ "//pkg/syserror",
+ "//pkg/usermem",
+ "//pkg/waiter",
+ ],
+)
diff --git a/pkg/sentry/fsimpl/signalfd/signalfd.go b/pkg/sentry/fsimpl/signalfd/signalfd.go
new file mode 100644
index 000000000..d29ef3f83
--- /dev/null
+++ b/pkg/sentry/fsimpl/signalfd/signalfd.go
@@ -0,0 +1,135 @@
+// Copyright 2019 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 signalfd
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+ "gvisor.dev/gvisor/pkg/waiter"
+)
+
+// SignalFileDescription implements FileDescriptionImpl for signal fds.
+type SignalFileDescription struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+
+ // target is the original signal target task.
+ //
+ // The semantics here are a bit broken. Linux will always use current
+ // for all reads, regardless of where the signalfd originated. We can't
+ // do exactly that because we need to plumb the context through
+ // EventRegister in order to support proper blocking behavior. This
+ // will undoubtedly become very complicated quickly.
+ target *kernel.Task
+
+ // mu protects mask.
+ mu sync.Mutex
+
+ // mask is the signal mask. Protected by mu.
+ mask linux.SignalSet
+}
+
+var _ vfs.FileDescriptionImpl = (*SignalFileDescription)(nil)
+
+// New creates a new signal fd.
+func New(vfsObj *vfs.VirtualFilesystem, target *kernel.Task, mask linux.SignalSet, flags uint32) (*vfs.FileDescription, error) {
+ vd := vfsObj.NewAnonVirtualDentry("[signalfd]")
+ defer vd.DecRef()
+ sfd := &SignalFileDescription{
+ target: target,
+ mask: mask,
+ }
+ if err := sfd.vfsfd.Init(sfd, flags, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{
+ UseDentryMetadata: true,
+ DenyPRead: true,
+ DenyPWrite: true,
+ }); err != nil {
+ return nil, err
+ }
+ return &sfd.vfsfd, nil
+}
+
+// Mask returns the signal mask.
+func (sfd *SignalFileDescription) Mask() linux.SignalSet {
+ sfd.mu.Lock()
+ defer sfd.mu.Unlock()
+ return sfd.mask
+}
+
+// SetMask sets the signal mask.
+func (sfd *SignalFileDescription) SetMask(mask linux.SignalSet) {
+ sfd.mu.Lock()
+ defer sfd.mu.Unlock()
+ sfd.mask = mask
+}
+
+// Read implements FileDescriptionImpl.Read.
+func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) {
+ // Attempt to dequeue relevant signals.
+ info, err := sfd.target.Sigtimedwait(sfd.Mask(), 0)
+ if err != nil {
+ // There must be no signal available.
+ return 0, syserror.ErrWouldBlock
+ }
+
+ // Copy out the signal info using the specified format.
+ var buf [128]byte
+ binary.Marshal(buf[:0], usermem.ByteOrder, &linux.SignalfdSiginfo{
+ Signo: uint32(info.Signo),
+ Errno: info.Errno,
+ Code: info.Code,
+ PID: uint32(info.Pid()),
+ UID: uint32(info.Uid()),
+ Status: info.Status(),
+ Overrun: uint32(info.Overrun()),
+ Addr: info.Addr(),
+ })
+ n, err := dst.CopyOut(ctx, buf[:])
+ return int64(n), err
+}
+
+// Readiness implements waiter.Waitable.Readiness.
+func (sfd *SignalFileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
+ sfd.mu.Lock()
+ defer sfd.mu.Unlock()
+ if mask&waiter.EventIn != 0 && sfd.target.PendingSignals()&sfd.mask != 0 {
+ return waiter.EventIn // Pending signals.
+ }
+ return 0
+}
+
+// EventRegister implements waiter.Waitable.EventRegister.
+func (sfd *SignalFileDescription) EventRegister(entry *waiter.Entry, _ waiter.EventMask) {
+ sfd.mu.Lock()
+ defer sfd.mu.Unlock()
+ // Register for the signal set; ignore the passed events.
+ sfd.target.SignalRegister(entry, waiter.EventMask(sfd.mask))
+}
+
+// EventUnregister implements waiter.Waitable.EventUnregister.
+func (sfd *SignalFileDescription) EventUnregister(entry *waiter.Entry) {
+ // Unregister the original entry.
+ sfd.target.SignalUnregister(entry)
+}
+
+// Release implements FileDescriptionImpl.Release()
+func (sfd *SignalFileDescription) Release() {}
diff --git a/pkg/sentry/syscalls/linux/sigset.go b/pkg/sentry/syscalls/linux/sigset.go
index 2ddb2b146..434559b80 100644
--- a/pkg/sentry/syscalls/linux/sigset.go
+++ b/pkg/sentry/syscalls/linux/sigset.go
@@ -21,9 +21,13 @@ import (
"gvisor.dev/gvisor/pkg/usermem"
)
-// copyInSigSet copies in a sigset_t, checks its size, and ensures that KILL and
+// 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) {
+//
+// TODO(gvisor.dev/issue/1624): This is only exported because
+// syscalls/vfs2/signal.go depends on it. Once vfs1 is deleted and the vfs2
+// syscalls are moved into this package, then they can be unexported.
+func CopyInSigSet(t *kernel.Task, sigSetAddr usermem.Addr, size uint) (linux.SignalSet, error) {
if size != linux.SignalSetSize {
return 0, syserror.EINVAL
}
diff --git a/pkg/sentry/syscalls/linux/sys_epoll.go b/pkg/sentry/syscalls/linux/sys_epoll.go
index 51bf205cf..7f460d30b 100644
--- a/pkg/sentry/syscalls/linux/sys_epoll.go
+++ b/pkg/sentry/syscalls/linux/sys_epoll.go
@@ -131,7 +131,7 @@ func EpollPwait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy
maskSize := uint(args[5].Uint())
if maskAddr != 0 {
- mask, err := copyInSigSet(t, maskAddr, maskSize)
+ mask, err := CopyInSigSet(t, maskAddr, maskSize)
if err != nil {
return 0, nil, err
}
diff --git a/pkg/sentry/syscalls/linux/sys_poll.go b/pkg/sentry/syscalls/linux/sys_poll.go
index 4f8762d7d..f0198141c 100644
--- a/pkg/sentry/syscalls/linux/sys_poll.go
+++ b/pkg/sentry/syscalls/linux/sys_poll.go
@@ -443,7 +443,7 @@ func Ppoll(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
}
if maskAddr != 0 {
- mask, err := copyInSigSet(t, maskAddr, maskSize)
+ mask, err := CopyInSigSet(t, maskAddr, maskSize)
if err != nil {
return 0, nil, err
}
@@ -525,7 +525,7 @@ func Pselect(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca
}
if maskAddr != 0 {
- mask, err := copyInSigSet(t, maskAddr, size)
+ mask, err := CopyInSigSet(t, maskAddr, size)
if err != nil {
return 0, nil, err
}
diff --git a/pkg/sentry/syscalls/linux/sys_signal.go b/pkg/sentry/syscalls/linux/sys_signal.go
index 582d37e03..d2b0012ae 100644
--- a/pkg/sentry/syscalls/linux/sys_signal.go
+++ b/pkg/sentry/syscalls/linux/sys_signal.go
@@ -295,7 +295,7 @@ func RtSigprocmask(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel
}
oldmask := t.SignalMask()
if setaddr != 0 {
- mask, err := copyInSigSet(t, setaddr, sigsetsize)
+ mask, err := CopyInSigSet(t, setaddr, sigsetsize)
if err != nil {
return 0, nil, err
}
@@ -366,7 +366,7 @@ func RtSigtimedwait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne
timespec := args[2].Pointer()
sigsetsize := args[3].SizeT()
- mask, err := copyInSigSet(t, sigset, sigsetsize)
+ mask, err := CopyInSigSet(t, sigset, sigsetsize)
if err != nil {
return 0, nil, err
}
@@ -518,7 +518,7 @@ func RestartSyscall(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne
// sharedSignalfd is shared between the two calls.
func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize uint, flags int32) (uintptr, *kernel.SyscallControl, error) {
// Copy in the signal mask.
- mask, err := copyInSigSet(t, sigset, sigsetsize)
+ mask, err := CopyInSigSet(t, sigset, sigsetsize)
if err != nil {
return 0, nil, err
}
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD
index 4c7b8f819..14838aa2c 100644
--- a/pkg/sentry/syscalls/linux/vfs2/BUILD
+++ b/pkg/sentry/syscalls/linux/vfs2/BUILD
@@ -19,6 +19,7 @@ go_library(
"poll.go",
"read_write.go",
"setstat.go",
+ "signal.go",
"socket.go",
"stat.go",
"stat_amd64.go",
@@ -39,6 +40,7 @@ go_library(
"//pkg/sentry/arch",
"//pkg/sentry/fsbridge",
"//pkg/sentry/fsimpl/pipefs",
+ "//pkg/sentry/fsimpl/signalfd",
"//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/kernel/pipe",
diff --git a/pkg/sentry/syscalls/linux/vfs2/signal.go b/pkg/sentry/syscalls/linux/vfs2/signal.go
new file mode 100644
index 000000000..623992f6f
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/vfs2/signal.go
@@ -0,0 +1,100 @@
+// Copyright 2018 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 (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/fsimpl/signalfd"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// sharedSignalfd is shared between the two calls.
+func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize uint, flags int32) (uintptr, *kernel.SyscallControl, error) {
+ // Copy in the signal mask.
+ mask, err := slinux.CopyInSigSet(t, sigset, sigsetsize)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ // Always check for valid flags, even if not creating.
+ if flags&^(linux.SFD_NONBLOCK|linux.SFD_CLOEXEC) != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ // Is this a change to an existing signalfd?
+ //
+ // The spec indicates that this should adjust the mask.
+ if fd != -1 {
+ file := t.GetFileVFS2(fd)
+ if file == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer file.DecRef()
+
+ // Is this a signalfd?
+ if sfd, ok := file.Impl().(*signalfd.SignalFileDescription); ok {
+ sfd.SetMask(mask)
+ return 0, nil, nil
+ }
+
+ // Not a signalfd.
+ return 0, nil, syserror.EINVAL
+ }
+
+ fileFlags := uint32(linux.O_RDWR)
+ if flags&linux.SFD_NONBLOCK != 0 {
+ fileFlags |= linux.O_NONBLOCK
+ }
+
+ // Create a new file.
+ vfsObj := t.Kernel().VFS()
+ file, err := signalfd.New(vfsObj, t, mask, fileFlags)
+ if err != nil {
+ return 0, nil, err
+ }
+ defer file.DecRef()
+
+ // Create a new descriptor.
+ fd, err = t.NewFDFromVFS2(0, file, kernel.FDFlags{
+ CloseOnExec: flags&linux.SFD_CLOEXEC != 0,
+ })
+ if err != nil {
+ return 0, nil, err
+ }
+
+ // Done.
+ return uintptr(fd), nil, nil
+}
+
+// Signalfd implements the linux syscall signalfd(2).
+func Signalfd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ sigset := args[1].Pointer()
+ sigsetsize := args[2].SizeT()
+ return sharedSignalfd(t, fd, sigset, sigsetsize, 0)
+}
+
+// Signalfd4 implements the linux syscall signalfd4(2).
+func Signalfd4(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ sigset := args[1].Pointer()
+ sigsetsize := args[2].SizeT()
+ flags := args[3].Int()
+ return sharedSignalfd(t, fd, sigset, sigsetsize, flags)
+}
diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
index f1b697844..9c04677f1 100644
--- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go
+++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
@@ -139,14 +139,14 @@ func Override() {
s.Table[277] = syscalls.Supported("sync_file_range", SyncFileRange)
s.Table[280] = syscalls.Supported("utimensat", Utimensat)
s.Table[281] = syscalls.Supported("epoll_pwait", EpollPwait)
- delete(s.Table, 282) // signalfd
+ s.Table[282] = syscalls.Supported("signalfd", Signalfd)
s.Table[283] = syscalls.Supported("timerfd_create", TimerfdCreate)
s.Table[284] = syscalls.Supported("eventfd", Eventfd)
delete(s.Table, 285) // fallocate
s.Table[286] = syscalls.Supported("timerfd_settime", TimerfdSettime)
s.Table[287] = syscalls.Supported("timerfd_gettime", TimerfdGettime)
s.Table[288] = syscalls.Supported("accept4", Accept4)
- delete(s.Table, 289) // signalfd4
+ s.Table[289] = syscalls.Supported("signalfd4", Signalfd4)
s.Table[290] = syscalls.Supported("eventfd2", Eventfd2)
s.Table[291] = syscalls.Supported("epoll_create1", EpollCreate1)
s.Table[292] = syscalls.Supported("dup3", Dup3)
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index c62505fe2..86046dd99 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -43,6 +43,7 @@ go_library(
visibility = ["//pkg/sentry:internal"],
deps = [
"//pkg/abi/linux",
+ "//pkg/binary",
"//pkg/context",
"//pkg/fd",
"//pkg/fdnotifier",
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 11:04:44 +0000