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Unified Diff: src/trap-handler/handler-outside.cc

Issue 2723133003: Revert of [wasm] Initial signal handler (Closed)
Patch Set: Created 3 years, 10 months ago
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Index: src/trap-handler/handler-outside.cc
diff --git a/src/trap-handler/handler-outside.cc b/src/trap-handler/handler-outside.cc
deleted file mode 100644
index ea1500e67e67ecbff6cbb528c0ef996bb5ecb0f5..0000000000000000000000000000000000000000
--- a/src/trap-handler/handler-outside.cc
+++ /dev/null
@@ -1,191 +0,0 @@
-// Copyright 2017 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// PLEASE READ BEFORE CHANGING THIS FILE!
-//
-// This file implements the support code for the out of bounds signal handler.
-// Nothing in here actually runs in the signal handler, but the code here
-// manipulates data structures used by the signal handler so we still need to be
-// careful. In order to minimize this risk, here are some rules to follow.
-//
-// 1. Avoid introducing new external dependencies. The files in src/trap-handler
-// should be as self-contained as possible to make it easy to audit the code.
-//
-// 2. Any changes must be reviewed by someone from the crash reporting
-// or security team. Se OWNERS for suggested reviewers.
-//
-// For more information, see https://goo.gl/yMeyUY.
-//
-// For the code that runs in the signal handler itself, see handler-inside.cc.
-
-#include <signal.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <atomic>
-#include <limits>
-
-#include "src/trap-handler/trap-handler-internal.h"
-#include "src/trap-handler/trap-handler.h"
-
-namespace {
-size_t gNextCodeObject = 0;
-}
-
-namespace v8 {
-namespace internal {
-namespace trap_handler {
-
-const size_t kInitialCodeObjectSize = 1024;
-const size_t kCodeObjectGrowthFactor = 2;
-
-constexpr size_t HandlerDataSize(size_t num_protected_instructions) {
- return offsetof(CodeProtectionInfo, instructions) +
- num_protected_instructions * sizeof(ProtectedInstructionData);
-}
-
-CodeProtectionInfo* CreateHandlerData(
- void* base, size_t size, size_t num_protected_instructions,
- ProtectedInstructionData* protected_instructions) {
- const size_t alloc_size = HandlerDataSize(num_protected_instructions);
- CodeProtectionInfo* data =
- reinterpret_cast<CodeProtectionInfo*>(malloc(alloc_size));
-
- if (data == nullptr) {
- return nullptr;
- }
-
- data->base = base;
- data->size = size;
- data->num_protected_instructions = num_protected_instructions;
-
- memcpy(data->instructions, protected_instructions,
- num_protected_instructions * sizeof(ProtectedInstructionData));
-
- return data;
-}
-
-void UpdateHandlerDataCodePointer(int index, void* base) {
- MetadataLock lock;
- if (static_cast<size_t>(index) >= gNumCodeObjects) {
- abort();
- }
- CodeProtectionInfo* data = gCodeObjects[index].code_info;
- data->base = base;
-}
-
-int RegisterHandlerData(void* base, size_t size,
- size_t num_protected_instructions,
- ProtectedInstructionData* protected_instructions) {
- // TODO(eholk): in debug builds, make sure this data isn't already registered.
-
- CodeProtectionInfo* data = CreateHandlerData(
- base, size, num_protected_instructions, protected_instructions);
-
- if (data == nullptr) {
- abort();
- }
-
- MetadataLock lock;
-
- size_t i = gNextCodeObject;
-
- // Explicitly convert std::numeric_limits<int>::max() to unsigned to avoid
- // compiler warnings about signed/unsigned comparisons. We aren't worried
- // about sign extension because we know std::numeric_limits<int>::max() is
- // positive.
- const size_t int_max = std::numeric_limits<int>::max();
-
- // We didn't find an opening in the available space, so grow.
- if (i == gNumCodeObjects) {
- size_t new_size = gNumCodeObjects > 0
- ? gNumCodeObjects * kCodeObjectGrowthFactor
- : kInitialCodeObjectSize;
-
- // Because we must return an int, there is no point in allocating space for
- // more objects than can fit in an int.
- if (new_size > int_max) {
- new_size = int_max;
- }
- if (new_size == gNumCodeObjects) {
- return -1;
- }
-
- // Now that we know our new size is valid, we can go ahead and realloc the
- // array.
- gCodeObjects = static_cast<CodeProtectionInfoListEntry*>(
- realloc(gCodeObjects, sizeof(*gCodeObjects) * new_size));
-
- if (gCodeObjects == nullptr) {
- abort();
- }
-
- memset(gCodeObjects + gNumCodeObjects, 0,
- sizeof(*gCodeObjects) * (new_size - gNumCodeObjects));
- gNumCodeObjects = new_size;
- }
-
- DCHECK(gCodeObjects[i].code_info == nullptr);
-
- // Find out where the next entry should go.
- if (gCodeObjects[i].next_free == 0) {
- // if this is a fresh entry, use the next one.
- gNextCodeObject = i + 1;
- DCHECK(gNextCodeObject == gNumCodeObjects ||
- (gCodeObjects[gNextCodeObject].code_info == nullptr &&
- gCodeObjects[gNextCodeObject].next_free == 0));
- } else {
- gNextCodeObject = gCodeObjects[i].next_free - 1;
- }
-
- if (i <= int_max) {
- gCodeObjects[i].code_info = data;
- return static_cast<int>(i);
- } else {
- return -1;
- }
-}
-
-void ReleaseHandlerData(int index) {
- // Remove the data from the global list if it's there.
- CodeProtectionInfo* data = nullptr;
- {
- MetadataLock lock;
-
- data = gCodeObjects[index].code_info;
- gCodeObjects[index].code_info = nullptr;
-
- // +1 because we reserve {next_entry == 0} to indicate a fresh list entry.
- gCodeObjects[index].next_free = gNextCodeObject + 1;
- gNextCodeObject = index;
- }
- // TODO(eholk): on debug builds, ensure there are no more copies in
- // the list.
- free(data);
-}
-
-bool RegisterDefaultSignalHandler() {
-#if V8_TRAP_HANDLER_SUPPORTED
- struct sigaction action;
- action.sa_sigaction = HandleSignal;
- action.sa_flags = SA_SIGINFO;
- sigemptyset(&action.sa_mask);
- // {sigaction} installs a new custom segfault handler. On success, it returns
- // 0. If we get a nonzero value, we report an error to the caller by returning
- // false.
- if (sigaction(SIGSEGV, &action, nullptr) != 0) {
- return false;
- }
-
- return true;
-#else
- return false;
-#endif
-}
-
-} // namespace trap_handler
-} // namespace internal
-} // namespace v8
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