2c4ae3b0a4
Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для неё не нужна. Module path github.com/sagernet/gvisor сохранён намеренно: на него опирается replace-директива суперпроекта. Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show и переносилась на новый пин копированием. SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH
103 lines
3.3 KiB
Go
103 lines
3.3 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build linux
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// +build linux
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package sighandling
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import (
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"fmt"
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"os"
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"unsafe"
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"github.com/sagernet/gvisor/pkg/abi/linux"
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"golang.org/x/sys/unix"
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)
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// IgnoreChildStop sets the SA_NOCLDSTOP flag, causing child processes to not
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// generate SIGCHLD when they stop.
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func IgnoreChildStop() error {
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var sa linux.SigAction
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// Get the existing signal handler information, and set the flag.
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if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), 0, uintptr(unsafe.Pointer(&sa)), linux.SignalSetSize, 0, 0); e != 0 {
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return e
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}
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sa.Flags |= linux.SA_NOCLDSTOP
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if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(unix.SIGCHLD), uintptr(unsafe.Pointer(&sa)), 0, linux.SignalSetSize, 0, 0); e != 0 {
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return e
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}
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return nil
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}
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// ReplaceSignalHandler replaces the existing signal handler for the provided
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// signal with the function pointer at `handler`. This bypasses the Go runtime
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// signal handlers, and should only be used for low-level signal handlers where
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// use of signal.Notify is not appropriate.
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//
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// It stores the value of the previously set handler in previous.
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func ReplaceSignalHandler(sig unix.Signal, handler uintptr, previous *uintptr) error {
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var sa linux.SigAction
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const maskLen = 8
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// Get the existing signal handler information, and save the current
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// handler. Once we replace it, we will use this pointer to fall back to
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// it when we receive other signals.
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if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
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return e
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}
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// Fail if there isn't a previous handler.
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if sa.Handler == 0 {
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return fmt.Errorf("previous handler for signal %x isn't set", sig)
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}
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*previous = uintptr(sa.Handler)
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// Install our own handler.
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sa.Handler = uint64(handler)
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if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
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return e
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}
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return nil
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}
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// KillItself sends SIGKILL to the current process, bypassing the init process
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// restriction.
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//
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// The standard `kill(getpid(), SIGKILL)` syscall doesn't work when the current
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// process is the init process within its PID namespace. This is a "known"
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// Linux feature.
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//
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// This function uses the rt_tgqueueinfo syscall to send a "kernel-generated"
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// SIGKILL.
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func KillItself() error {
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pid := os.Getpid()
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tid, _, _ := unix.RawSyscall(unix.SYS_GETTID, 0, 0, 0)
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info := linux.SignalInfo{Code: linux.SI_KERNEL}
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// The current thread can send a fake kernel siginfo to itself.
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if _, _, e := unix.RawSyscall6(
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unix.SYS_RT_TGSIGQUEUEINFO,
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uintptr(pid), uintptr(tid),
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uintptr(linux.SIGKILL),
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uintptr(unsafe.Pointer(&info)),
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0, 0,
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); e != 0 {
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return e
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}
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panic("unreachable")
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}
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