From 0e2f1b7abd219f39d67cc2cecd00c441a13eeb29 Mon Sep 17 00:00:00 2001 From: Adin Scannell Date: Mon, 27 Jan 2020 15:17:58 -0800 Subject: Update package locations. Because the abi will depend on the core types for marshalling (usermem, context, safemem, safecopy), these need to be flattened from the sentry directory. These packages contain no sentry-specific details. PiperOrigin-RevId: 291811289 --- pkg/sentry/platform/safecopy/safecopy.go | 144 ------------------------------- 1 file changed, 144 deletions(-) delete mode 100644 pkg/sentry/platform/safecopy/safecopy.go (limited to 'pkg/sentry/platform/safecopy/safecopy.go') diff --git a/pkg/sentry/platform/safecopy/safecopy.go b/pkg/sentry/platform/safecopy/safecopy.go deleted file mode 100644 index 2fb7e5809..000000000 --- a/pkg/sentry/platform/safecopy/safecopy.go +++ /dev/null @@ -1,144 +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 safecopy provides an efficient implementation of functions to access -// memory that may result in SIGSEGV or SIGBUS being sent to the accessor. -package safecopy - -import ( - "fmt" - "reflect" - "runtime" - "syscall" - - "gvisor.dev/gvisor/pkg/syserror" -) - -// SegvError is returned when a safecopy function receives SIGSEGV. -type SegvError struct { - // Addr is the address at which the SIGSEGV occurred. - Addr uintptr -} - -// Error implements error.Error. -func (e SegvError) Error() string { - return fmt.Sprintf("SIGSEGV at %#x", e.Addr) -} - -// BusError is returned when a safecopy function receives SIGBUS. -type BusError struct { - // Addr is the address at which the SIGBUS occurred. - Addr uintptr -} - -// Error implements error.Error. -func (e BusError) Error() string { - return fmt.Sprintf("SIGBUS at %#x", e.Addr) -} - -// AlignmentError is returned when a safecopy function is passed an address -// that does not meet alignment requirements. -type AlignmentError struct { - // Addr is the invalid address. - Addr uintptr - - // Alignment is the required alignment. - Alignment uintptr -} - -// Error implements error.Error. -func (e AlignmentError) Error() string { - return fmt.Sprintf("address %#x is not aligned to a %d-byte boundary", e.Addr, e.Alignment) -} - -var ( - // The begin and end addresses below are for the functions that are - // checked by the signal handler. - memcpyBegin uintptr - memcpyEnd uintptr - memclrBegin uintptr - memclrEnd uintptr - swapUint32Begin uintptr - swapUint32End uintptr - swapUint64Begin uintptr - swapUint64End uintptr - compareAndSwapUint32Begin uintptr - compareAndSwapUint32End uintptr - loadUint32Begin uintptr - loadUint32End uintptr - - // savedSigSegVHandler is a pointer to the SIGSEGV handler that was - // configured before we replaced it with our own. We still call into it - // when we get a SIGSEGV that is not interesting to us. - savedSigSegVHandler uintptr - - // same a above, but for SIGBUS signals. - savedSigBusHandler uintptr -) - -// signalHandler is our replacement signal handler for SIGSEGV and SIGBUS -// signals. -func signalHandler() - -// FindEndAddress returns the end address (one byte beyond the last) of the -// function that contains the specified address (begin). -func FindEndAddress(begin uintptr) uintptr { - f := runtime.FuncForPC(begin) - if f != nil { - for p := begin; ; p++ { - g := runtime.FuncForPC(p) - if f != g { - return p - } - } - } - return begin -} - -// initializeAddresses initializes the addresses used by the signal handler. -func initializeAddresses() { - // The following functions are written in assembly language, so they won't - // be inlined by the existing compiler/linker. Tests will fail if this - // assumption is violated. - memcpyBegin = reflect.ValueOf(memcpy).Pointer() - memcpyEnd = FindEndAddress(memcpyBegin) - memclrBegin = reflect.ValueOf(memclr).Pointer() - memclrEnd = FindEndAddress(memclrBegin) - swapUint32Begin = reflect.ValueOf(swapUint32).Pointer() - swapUint32End = FindEndAddress(swapUint32Begin) - swapUint64Begin = reflect.ValueOf(swapUint64).Pointer() - swapUint64End = FindEndAddress(swapUint64Begin) - compareAndSwapUint32Begin = reflect.ValueOf(compareAndSwapUint32).Pointer() - compareAndSwapUint32End = FindEndAddress(compareAndSwapUint32Begin) - loadUint32Begin = reflect.ValueOf(loadUint32).Pointer() - loadUint32End = FindEndAddress(loadUint32Begin) -} - -func init() { - initializeAddresses() - if err := ReplaceSignalHandler(syscall.SIGSEGV, reflect.ValueOf(signalHandler).Pointer(), &savedSigSegVHandler); err != nil { - panic(fmt.Sprintf("Unable to set handler for SIGSEGV: %v", err)) - } - if err := ReplaceSignalHandler(syscall.SIGBUS, reflect.ValueOf(signalHandler).Pointer(), &savedSigBusHandler); err != nil { - panic(fmt.Sprintf("Unable to set handler for SIGBUS: %v", err)) - } - syserror.AddErrorUnwrapper(func(e error) (syscall.Errno, bool) { - switch e.(type) { - case SegvError, BusError, AlignmentError: - return syscall.EFAULT, true - default: - return 0, false - } - }) -} -- cgit v1.2.3