ipc/glue/SharedMemory.h@6474c204b198 (annotated)
ipc/glue/SharedMemory.h
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
| michael@0 | 2 | * vim: sw=2 ts=8 et : |
| michael@0 | 3 | */ |
| michael@0 | 4 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 5 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 6 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 7 | |
| michael@0 | 8 | #ifndef mozilla_ipc_SharedMemory_h |
| michael@0 | 9 | #define mozilla_ipc_SharedMemory_h |
| michael@0 | 10 | |
| michael@0 | 11 | #include "nsDebug.h" |
| michael@0 | 12 | #include "nsISupportsImpl.h" // NS_INLINE_DECL_REFCOUNTING |
| michael@0 | 13 | #include "mozilla/Attributes.h" |
| michael@0 | 14 | |
| michael@0 | 15 | // |
| michael@0 | 16 | // This is a low-level wrapper around platform shared memory. Don't |
| michael@0 | 17 | // use it directly; use Shmem allocated through IPDL interfaces. |
| michael@0 | 18 | // |
| michael@0 | 19 | namespace { |
| michael@0 | 20 | enum Rights { |
| michael@0 | 21 | RightsNone = 0, |
| michael@0 | 22 | RightsRead = 1 << 0, |
| michael@0 | 23 | RightsWrite = 1 << 1 |
| michael@0 | 24 | }; |
| michael@0 | 25 | } |
| michael@0 | 26 | |
| michael@0 | 27 | namespace mozilla { |
| michael@0 | 28 | namespace ipc { |
| michael@0 | 29 | |
| michael@0 | 30 | class SharedMemory |
| michael@0 | 31 | { |
| michael@0 | 32 | public: |
| michael@0 | 33 | virtual ~SharedMemory() |
| michael@0 | 34 | { |
| michael@0 | 35 | MOZ_COUNT_DTOR(SharedMemory); |
| michael@0 | 36 | Unmapped(); |
| michael@0 | 37 | Destroyed(); |
| michael@0 | 38 | } |
| michael@0 | 39 | |
| michael@0 | 40 | enum SharedMemoryType { |
| michael@0 | 41 | TYPE_BASIC, |
| michael@0 | 42 | TYPE_SYSV, |
| michael@0 | 43 | TYPE_UNKNOWN |
| michael@0 | 44 | }; |
| michael@0 | 45 | |
| michael@0 | 46 | size_t Size() const { return mMappedSize; } |
| michael@0 | 47 | |
| michael@0 | 48 | virtual void* memory() const = 0; |
| michael@0 | 49 | |
| michael@0 | 50 | virtual bool Create(size_t size) = 0; |
| michael@0 | 51 | virtual bool Map(size_t nBytes) = 0; |
| michael@0 | 52 | |
| michael@0 | 53 | virtual SharedMemoryType Type() const = 0; |
| michael@0 | 54 | |
| michael@0 | 55 | void |
| michael@0 | 56 | Protect(char* aAddr, size_t aSize, int aRights) |
| michael@0 | 57 | { |
| michael@0 | 58 | char* memStart = reinterpret_cast<char*>(memory()); |
| michael@0 | 59 | if (!memStart) |
| michael@0 | 60 | NS_RUNTIMEABORT("SharedMemory region points at NULL!"); |
| michael@0 | 61 | char* memEnd = memStart + Size(); |
| michael@0 | 62 | |
| michael@0 | 63 | char* protStart = aAddr; |
| michael@0 | 64 | if (!protStart) |
| michael@0 | 65 | NS_RUNTIMEABORT("trying to Protect() a NULL region!"); |
| michael@0 | 66 | char* protEnd = protStart + aSize; |
| michael@0 | 67 | |
| michael@0 | 68 | if (!(memStart <= protStart |
| michael@0 | 69 | && protEnd <= memEnd)) |
| michael@0 | 70 | NS_RUNTIMEABORT("attempt to Protect() a region outside this SharedMemory"); |
| michael@0 | 71 | |
| michael@0 | 72 | // checks alignment etc. |
| michael@0 | 73 | SystemProtect(aAddr, aSize, aRights); |
| michael@0 | 74 | } |
| michael@0 | 75 | |
| michael@0 | 76 | NS_INLINE_DECL_REFCOUNTING(SharedMemory) |
| michael@0 | 77 | |
| michael@0 | 78 | static void SystemProtect(char* aAddr, size_t aSize, int aRights); |
| michael@0 | 79 | static size_t SystemPageSize(); |
| michael@0 | 80 | static size_t PageAlignedSize(size_t aSize); |
| michael@0 | 81 | |
| michael@0 | 82 | protected: |
| michael@0 | 83 | SharedMemory(); |
| michael@0 | 84 | |
| michael@0 | 85 | // Implementations should call these methods on shmem usage changes, |
| michael@0 | 86 | // but *only if* the OS-specific calls are known to have succeeded. |
| michael@0 | 87 | // The methods are expected to be called in the pattern |
| michael@0 | 88 | // |
| michael@0 | 89 | // Created (Mapped Unmapped)* Destroy |
| michael@0 | 90 | // |
| michael@0 | 91 | // but this isn't checked. |
| michael@0 | 92 | void Created(size_t aNBytes); |
| michael@0 | 93 | void Mapped(size_t aNBytes); |
| michael@0 | 94 | void Unmapped(); |
| michael@0 | 95 | void Destroyed(); |
| michael@0 | 96 | |
| michael@0 | 97 | // The size of the shmem region requested in Create(), if |
| michael@0 | 98 | // successful. SharedMemory instances that are opened from a |
| michael@0 | 99 | // foreign handle have an alloc size of 0, even though they have |
| michael@0 | 100 | // access to the alloc-size information. |
| michael@0 | 101 | size_t mAllocSize; |
| michael@0 | 102 | // The size of the region mapped in Map(), if successful. All |
| michael@0 | 103 | // SharedMemorys that are mapped have a non-zero mapped size. |
| michael@0 | 104 | size_t mMappedSize; |
| michael@0 | 105 | }; |
| michael@0 | 106 | |
| michael@0 | 107 | } // namespace ipc |
| michael@0 | 108 | } // namespace mozilla |
| michael@0 | 109 | |
| michael@0 | 110 | |
| michael@0 | 111 | #endif // ifndef mozilla_ipc_SharedMemory_h |
