forked from mirrors/gecko-dev
e38691d6e6
The most important part is the `GetPHCAddrInfo()` function in `exception_handler.cc`, which extracts a crash address from an `EXCEPTION_POINTERS` object. The commit also changes the code so that it works if MozStackWalk() returns an empty stack trace. This happens in practice on Windows on automation sometimes, I'm not sure why. The rest of the commit is just plumbing and the smoothing over of minor platform differences. Differential Revision: https://phabricator.services.mozilla.com/D39841 --HG-- extra : moz-landing-system : lando
91 lines
2.7 KiB
C++
91 lines
2.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef PHC_h
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#define PHC_h
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#include "mozilla/Assertions.h"
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#include "mozilla/Maybe.h"
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#include <stdint.h>
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#include <stdlib.h>
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namespace mozilla {
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namespace phc {
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// Note: a stack trace may have no frames due to a collection problem.
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//
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// Also note: a more compact stack trace representation could be achieved with
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// some effort.
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struct StackTrace {
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public:
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static const size_t kMaxFrames = 16;
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// The number of PCs in the stack trace.
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size_t mLength;
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// The PCs in the stack trace. Only the first mLength are initialized.
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const void* mPcs[kMaxFrames];
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public:
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StackTrace() : mLength(0) {}
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};
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// Info from PHC about an address in memory.
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class AddrInfo {
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public:
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enum class Kind {
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// The address is not in PHC-managed memory.
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Unknown = 0,
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// The address is within a PHC page that has never been allocated. A crash
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// involving such an address is unlikely in practice, because it would
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// require the crash to happen quite early.
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NeverAllocatedPage = 1,
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// The address is within a PHC page that is in use.
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InUsePage = 2,
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// The address is within a PHC page that has been allocated and then freed.
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// A crash involving such an address most likely indicates a
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// use-after-free. (A sufficiently wild write -- e.g. a large buffer
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// overflow -- could also trigger it, but this is less likely.)
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FreedPage = 3,
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// The address is within a PHC guard page. A crash involving such an
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// address most likely indicates a buffer overflow. (Again, a sufficiently
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// wild write could unluckily trigger it, but this is less likely.)
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//
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// NOTE: guard pages are not yet implemented. This value is present so they
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// can be added easily in the future.
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GuardPage = 4,
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};
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Kind mKind;
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// The base address of the containing PHC allocation, if there is one.
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const void* mBaseAddr;
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// The usable size of the containing PHC allocation, if there is one.
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size_t mUsableSize;
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// The allocation and free stack traces of the containing PHC allocation, if
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// there is one.
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mozilla::Maybe<StackTrace> mAllocStack;
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mozilla::Maybe<StackTrace> mFreeStack;
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// Default to no PHC info.
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AddrInfo()
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: mKind(Kind::Unknown),
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mBaseAddr(nullptr),
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mUsableSize(0),
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mAllocStack(),
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mFreeStack() {}
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};
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} // namespace phc
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} // namespace mozilla
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#endif /* PHC_h */
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