diff options
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/sighandling/BUILD | 16 | ||||
| -rw-r--r-- | pkg/sentry/sighandling/sighandling.go | 102 | ||||
| -rw-r--r-- | pkg/sentry/sighandling/sighandling_unsafe.go | 39 |
3 files changed, 0 insertions, 157 deletions
diff --git a/pkg/sentry/sighandling/BUILD b/pkg/sentry/sighandling/BUILD deleted file mode 100644 index 1790d57c9..000000000 --- a/pkg/sentry/sighandling/BUILD +++ /dev/null @@ -1,16 +0,0 @@ -load("//tools:defs.bzl", "go_library") - -package(licenses = ["notice"]) - -go_library( - name = "sighandling", - srcs = [ - "sighandling.go", - "sighandling_unsafe.go", - ], - visibility = ["//pkg/sentry:internal"], - deps = [ - "//pkg/abi/linux", - "@org_golang_x_sys//unix:go_default_library", - ], -) diff --git a/pkg/sentry/sighandling/sighandling.go b/pkg/sentry/sighandling/sighandling.go deleted file mode 100644 index bdaf8af29..000000000 --- a/pkg/sentry/sighandling/sighandling.go +++ /dev/null @@ -1,102 +0,0 @@ -// 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 sighandling contains helpers for handling signals to applications. -package sighandling - -import ( - "os" - "os/signal" - "reflect" - - "golang.org/x/sys/unix" - "gvisor.dev/gvisor/pkg/abi/linux" -) - -// numSignals is the number of normal (non-realtime) signals on Linux. -const numSignals = 32 - -// handleSignals listens for incoming signals and calls the given handler -// function. -// -// It stops when the stop channel is closed. The done channel is closed once it -// will no longer deliver signals to k. -func handleSignals(sigchans []chan os.Signal, handler func(linux.Signal), stop, done chan struct{}) { - // Build a select case. - sc := []reflect.SelectCase{{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(stop)}} - for _, sigchan := range sigchans { - sc = append(sc, reflect.SelectCase{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(sigchan)}) - } - - for { - // Wait for a notification. - index, _, ok := reflect.Select(sc) - - // Was it the stop channel? - if index == 0 { - if !ok { - // Stop forwarding and notify that it's done. - close(done) - return - } - continue - } - - // How about a different close? - if !ok { - panic("signal channel closed unexpectedly") - } - - // Otherwise, it was a signal on channel N. Index 0 represents the stop - // channel, so index N represents the channel for signal N. - handler(linux.Signal(index)) - } -} - -// StartSignalForwarding ensures that synchronous signals are passed to the -// given handler function and returns a callback that stops signal delivery. -// -// Note that this function permanently takes over signal handling. After the -// stop callback, signals revert to the default Go runtime behavior, which -// cannot be overridden with external calls to signal.Notify. -func StartSignalForwarding(handler func(linux.Signal)) func() { - stop := make(chan struct{}) - done := make(chan struct{}) - - // Register individual channels. One channel per standard signal is - // required as os.Notify() is non-blocking and may drop signals. To avoid - // this, standard signals have to be queued separately. Channel size 1 is - // enough for standard signals as their semantics allow de-duplication. - // - // External real-time signals are not supported. We rely on the go-runtime - // for their handling. - var sigchans []chan os.Signal - for sig := 1; sig <= numSignals+1; sig++ { - sigchan := make(chan os.Signal, 1) - sigchans = append(sigchans, sigchan) - - // SIGURG is used by Go's runtime scheduler. - if sig == int(linux.SIGURG) { - continue - } - signal.Notify(sigchan, unix.Signal(sig)) - } - // Start up our listener. - go handleSignals(sigchans, handler, stop, done) // S/R-SAFE: synchronized by Kernel.extMu. - - return func() { - close(stop) - <-done - } -} diff --git a/pkg/sentry/sighandling/sighandling_unsafe.go b/pkg/sentry/sighandling/sighandling_unsafe.go deleted file mode 100644 index 3fe5c6770..000000000 --- a/pkg/sentry/sighandling/sighandling_unsafe.go +++ /dev/null @@ -1,39 +0,0 @@ -// 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 sighandling - -import ( - "unsafe" - - "golang.org/x/sys/unix" - "gvisor.dev/gvisor/pkg/abi/linux" -) - -// IgnoreChildStop sets the SA_NOCLDSTOP flag, causing child processes to not -// generate SIGCHLD when they stop. -func IgnoreChildStop() error { - var sa linux.SigAction - - // Get the existing signal handler information, and set the flag. - if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), 0, uintptr(unsafe.Pointer(&sa)), linux.SignalSetSize, 0, 0); e != 0 { - return e - } - sa.Flags |= linux.SA_NOCLDSTOP - if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), uintptr(unsafe.Pointer(&sa)), 0, linux.SignalSetSize, 0, 0); e != 0 { - return e - } - - return nil -} |