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// Copyright 2021 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.
//go:build amd64
// +build amd64
package systrap
import (
"fmt"
"runtime"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/sentry/arch"
)
func (t *syscallThread) detach() {
p := t.thread
// The syscall thread can't handle any signals and doesn't expect to
// receive anything.
t.maskAllSignalsAttached()
regs := p.initRegs
regs.Rsp = 0
regs.R12 = uint64(t.stubAddr)
regs.R13 = uint64(t.sentryMessage.state + 1)
if t.seccompNotify != nil {
regs.Rbx = _RUN_SECCOMP_LOOP
} else {
regs.Rbx = _RUN_SYSCALL_LOOP
}
// Skip the syscall instruction.
regs.Rip += arch.SyscallWidth
if err := p.setRegs(®s); err != nil {
panic(fmt.Sprintf("ptrace set regs failed: %v", err))
}
p.detach()
if _, _, e := unix.RawSyscall(unix.SYS_TGKILL, uintptr(p.tgid), uintptr(p.tid), uintptr(unix.SIGCONT)); e != 0 {
panic(fmt.Sprintf("tkill failed: %v", e))
}
runtime.UnlockOSThread()
if t.seccompNotify != nil {
if err := t.waitForSeccompNotify(); err != nil {
panic(fmt.Sprintf("%s", err))
}
}
}
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