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28354d11c3
This CL introduces a new class ScopedVMMap, a fork of ScopedVMRead which maps the memory using vm_remap() instead of reading it. This is useful for Annotations which use ScopedSpinGuard to protect reads from simultaneous writes; the in-process intermediate dump handler can try to take the spin guard when reading such an Annotation and skip reading it if it the spin guard could not be obtained. Change-Id: I60d7a48d1ba4e5d2dfdb44307b78b4d9ffb73560 Bug: crashpad:437 Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/4114550 Reviewed-by: Mark Mentovai <mark@chromium.org> Commit-Queue: Ben Hamilton <benhamilton@google.com>
87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
// Copyright 2023 The Crashpad 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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#include "util/ios/scoped_vm_map.h"
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#include "util/ios/raw_logging.h"
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namespace crashpad {
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namespace internal {
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ScopedVMMapInternal::ScopedVMMapInternal()
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: data_(0),
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region_start_(0),
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region_size_(0),
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cur_protection_(VM_PROT_NONE) {}
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ScopedVMMapInternal::~ScopedVMMapInternal() {
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Reset();
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}
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bool ScopedVMMapInternal::Map(const void* data, const size_t data_length) {
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Reset();
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vm_address_t data_address = reinterpret_cast<vm_address_t>(data);
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vm_address_t page_region_address = trunc_page(data_address);
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region_size_ = round_page(data_address - page_region_address + data_length);
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if (region_size_ < data_length) {
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CRASHPAD_RAW_LOG("ScopedVMMap data_length overflow");
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return false;
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}
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// Since region_start_ is 0, vm_remap() will choose an address to which the
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// memory will be mapped and store the mapped address in region_start_ on
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// success.
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vm_prot_t max_protection;
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kern_return_t kr = vm_remap(mach_task_self(),
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®ion_start_,
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region_size_,
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0,
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TRUE,
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mach_task_self(),
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page_region_address,
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FALSE,
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&cur_protection_,
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&max_protection,
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VM_INHERIT_DEFAULT);
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if (kr != KERN_SUCCESS) {
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// It's expected that this will sometimes fail. Don't log here.
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return false;
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}
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data_ = region_start_ + (data_address - page_region_address);
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return true;
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}
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void ScopedVMMapInternal::Reset() {
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if (!region_start_) {
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return;
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}
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kern_return_t kr =
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vm_deallocate(mach_task_self(), region_start_, region_size_);
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if (kr != KERN_SUCCESS) {
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CRASHPAD_RAW_LOG_ERROR(kr, "vm_deallocate");
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}
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data_ = 0;
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region_start_ = 0;
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region_size_ = 0;
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cur_protection_ = VM_PROT_NONE;
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}
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} // namespace internal
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} // namespace crashpad
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