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116 lines
4.2 KiB
C++
116 lines
4.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=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 AutoObjectMapper_h
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#define AutoObjectMapper_h
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#include <string>
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#include "mozilla/Attributes.h"
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#include "PlatformMacros.h"
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// A (nearly-) RAII class that maps an object in and then unmaps it on
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// destruction. This base class version uses the "normal" POSIX
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// functions: open, fstat, close, mmap, munmap.
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class MOZ_STACK_CLASS AutoObjectMapperPOSIX {
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public:
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// The constructor does not attempt to map the file, because that
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// might fail. Instead, once the object has been constructed,
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// call Map() to attempt the mapping. There is no corresponding
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// Unmap() since the unmapping is done in the destructor. Failure
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// messages are sent to |aLog|.
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explicit AutoObjectMapperPOSIX(void(*aLog)(const char*));
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// Unmap the file on destruction of this object.
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~AutoObjectMapperPOSIX();
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// Map |fileName| into the address space and return the mapping
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// extents. If the file is zero sized this will fail. The file is
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// mapped read-only and private. Returns true iff the mapping
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// succeeded, in which case *start and *length hold its extent.
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// Once a call to Map succeeds, all subsequent calls to it will
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// fail.
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bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);
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protected:
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// If we are currently holding a mapped object, these record the
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// mapped address range.
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void* mImage;
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size_t mSize;
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// A logging sink, for complaining about mapping failures.
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void (*mLog)(const char*);
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private:
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// Are we currently holding a mapped object? This is private to
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// the base class. Derived classes need to have their own way to
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// track whether they are holding a mapped object.
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bool mIsMapped;
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// Disable copying and assignment.
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AutoObjectMapperPOSIX(const AutoObjectMapperPOSIX&);
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AutoObjectMapperPOSIX& operator=(const AutoObjectMapperPOSIX&);
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// Disable heap allocation of this class.
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void* operator new(size_t);
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void* operator new[](size_t);
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void operator delete(void*);
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void operator delete[](void*);
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};
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#if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
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// This is a variant of AutoObjectMapperPOSIX suitable for use in
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// conjunction with faulty.lib on Android. How it behaves depends on
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// the name of the file to be mapped. There are three possible cases:
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//
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// (1) /foo/bar/xyzzy/blah.apk!/libwurble.so
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// We hand it as-is to faulty.lib and let it fish the relevant
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// bits out of the APK.
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//
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// (2) libmozglue.so
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// This is part of the Fennec installation, but is not in the
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// APK. Instead we have to figure out the installation path
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// and look for it there. Because of faulty.lib limitations,
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// we have to use regular open/mmap instead of faulty.lib.
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//
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// (3) libanythingelse.so
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// faulty.lib assumes this is a system library, and prepends
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// "/system/lib/" to the path. So as in (1), we can give it
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// as-is to faulty.lib.
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//
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// Hence (1) and (3) require special-casing here. Case (2) simply
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// hands the problem to the parent class.
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class MOZ_STACK_CLASS AutoObjectMapperFaultyLib : public AutoObjectMapperPOSIX {
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public:
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AutoObjectMapperFaultyLib(void(*aLog)(const char*));
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~AutoObjectMapperFaultyLib();
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bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);
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private:
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// faulty.lib requires us to maintain an abstract handle that can be
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// used later to unmap the area. If this is non-NULL, it is assumed
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// that unmapping is to be done by faulty.lib. Otherwise it goes
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// via the normal mechanism.
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void* mHdl;
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// Disable copying and assignment.
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AutoObjectMapperFaultyLib(const AutoObjectMapperFaultyLib&);
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AutoObjectMapperFaultyLib& operator=(const AutoObjectMapperFaultyLib&);
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// Disable heap allocation of this class.
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void* operator new(size_t);
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void* operator new[](size_t);
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void operator delete(void*);
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void operator delete[](void*);
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};
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#endif // defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
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#endif // AutoObjectMapper_h
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