ipc/glue/FileDescriptor.h@6474c204b198 (annotated)
ipc/glue/FileDescriptor.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 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | #ifndef mozilla_ipc_FileDescriptor_h |
| michael@0 | 6 | #define mozilla_ipc_FileDescriptor_h |
| michael@0 | 7 | |
| michael@0 | 8 | #include "base/basictypes.h" |
| michael@0 | 9 | #include "base/process.h" |
| michael@0 | 10 | #include "mozilla/DebugOnly.h" |
| michael@0 | 11 | #include "nscore.h" |
| michael@0 | 12 | |
| michael@0 | 13 | #ifdef XP_WIN |
| michael@0 | 14 | // Need the HANDLE typedef. |
| michael@0 | 15 | #include <winnt.h> |
| michael@0 | 16 | #else |
| michael@0 | 17 | #include "base/file_descriptor_posix.h" |
| michael@0 | 18 | #endif |
| michael@0 | 19 | |
| michael@0 | 20 | namespace mozilla { |
| michael@0 | 21 | namespace ipc { |
| michael@0 | 22 | |
| michael@0 | 23 | // This class is used by IPDL to share file descriptors across processes. When |
| michael@0 | 24 | // sending a FileDescriptor IPDL will first duplicate a platform-specific file |
| michael@0 | 25 | // handle type ('PlatformHandleType') into a handle that is valid in the other |
| michael@0 | 26 | // process. Then IPDL will convert the duplicated handle into a type suitable |
| michael@0 | 27 | // for pickling ('PickleType') and then send that through the IPC pipe. In the |
| michael@0 | 28 | // receiving process the pickled data is converted into a platform-specific file |
| michael@0 | 29 | // handle and then returned to the receiver. |
| michael@0 | 30 | // |
| michael@0 | 31 | // To use this class add 'FileDescriptor' as an argument in the IPDL protocol |
| michael@0 | 32 | // and then pass a file descriptor from C++ to the Call/Send method. The |
| michael@0 | 33 | // Answer/Recv method will receive a FileDescriptor& on which PlatformHandle() |
| michael@0 | 34 | // can be called to return the platform file handle. |
| michael@0 | 35 | class FileDescriptor |
| michael@0 | 36 | { |
| michael@0 | 37 | public: |
| michael@0 | 38 | typedef base::ProcessHandle ProcessHandle; |
| michael@0 | 39 | |
| michael@0 | 40 | #ifdef XP_WIN |
| michael@0 | 41 | typedef HANDLE PlatformHandleType; |
| michael@0 | 42 | typedef HANDLE PickleType; |
| michael@0 | 43 | #else |
| michael@0 | 44 | typedef int PlatformHandleType; |
| michael@0 | 45 | typedef base::FileDescriptor PickleType; |
| michael@0 | 46 | #endif |
| michael@0 | 47 | |
| michael@0 | 48 | // This should only ever be created by IPDL. |
| michael@0 | 49 | struct IPDLPrivate |
| michael@0 | 50 | {}; |
| michael@0 | 51 | |
| michael@0 | 52 | FileDescriptor(); |
| michael@0 | 53 | |
| michael@0 | 54 | FileDescriptor(const FileDescriptor& aOther) |
| michael@0 | 55 | : mHandleCreatedByOtherProcess(false), |
| michael@0 | 56 | mHandleCreatedByOtherProcessWasUsed(false) |
| michael@0 | 57 | { |
| michael@0 | 58 | // Don't use operator= here because that will call |
| michael@0 | 59 | // CloseCurrentProcessHandle() on this (uninitialized) object. |
| michael@0 | 60 | Assign(aOther); |
| michael@0 | 61 | } |
| michael@0 | 62 | |
| michael@0 | 63 | FileDescriptor(PlatformHandleType aHandle); |
| michael@0 | 64 | |
| michael@0 | 65 | FileDescriptor(const IPDLPrivate&, const PickleType& aPickle) |
| michael@0 | 66 | #ifdef XP_WIN |
| michael@0 | 67 | : mHandle(aPickle) |
| michael@0 | 68 | #else |
| michael@0 | 69 | : mHandle(aPickle.fd) |
| michael@0 | 70 | #endif |
| michael@0 | 71 | , mHandleCreatedByOtherProcess(true) |
| michael@0 | 72 | , mHandleCreatedByOtherProcessWasUsed(false) |
| michael@0 | 73 | { } |
| michael@0 | 74 | |
| michael@0 | 75 | ~FileDescriptor() |
| michael@0 | 76 | { |
| michael@0 | 77 | CloseCurrentProcessHandle(); |
| michael@0 | 78 | } |
| michael@0 | 79 | |
| michael@0 | 80 | FileDescriptor& |
| michael@0 | 81 | operator=(const FileDescriptor& aOther) |
| michael@0 | 82 | { |
| michael@0 | 83 | CloseCurrentProcessHandle(); |
| michael@0 | 84 | Assign(aOther); |
| michael@0 | 85 | return *this; |
| michael@0 | 86 | } |
| michael@0 | 87 | |
| michael@0 | 88 | // Performs platform-specific actions to duplicate mHandle in the other |
| michael@0 | 89 | // process (e.g. dup() on POSIX, DuplicateHandle() on Windows). Returns a |
| michael@0 | 90 | // pickled value that can be passed to the other process via IPC. |
| michael@0 | 91 | PickleType |
| michael@0 | 92 | ShareTo(const IPDLPrivate&, ProcessHandle aOtherProcess) const; |
| michael@0 | 93 | |
| michael@0 | 94 | // Tests mHandle against a well-known invalid platform-specific file handle |
| michael@0 | 95 | // (e.g. -1 on POSIX, INVALID_HANDLE_VALUE on Windows). |
| michael@0 | 96 | bool |
| michael@0 | 97 | IsValid() const |
| michael@0 | 98 | { |
| michael@0 | 99 | return IsValid(mHandle); |
| michael@0 | 100 | } |
| michael@0 | 101 | |
| michael@0 | 102 | PlatformHandleType |
| michael@0 | 103 | PlatformHandle() const |
| michael@0 | 104 | { |
| michael@0 | 105 | if (mHandleCreatedByOtherProcess) { |
| michael@0 | 106 | mHandleCreatedByOtherProcessWasUsed = true; |
| michael@0 | 107 | } |
| michael@0 | 108 | return mHandle; |
| michael@0 | 109 | } |
| michael@0 | 110 | |
| michael@0 | 111 | bool |
| michael@0 | 112 | operator==(const FileDescriptor& aOther) const |
| michael@0 | 113 | { |
| michael@0 | 114 | return mHandle == aOther.mHandle; |
| michael@0 | 115 | } |
| michael@0 | 116 | |
| michael@0 | 117 | private: |
| michael@0 | 118 | void |
| michael@0 | 119 | Assign(const FileDescriptor& aOther) |
| michael@0 | 120 | { |
| michael@0 | 121 | if (aOther.mHandleCreatedByOtherProcess) { |
| michael@0 | 122 | mHandleCreatedByOtherProcess = true; |
| michael@0 | 123 | mHandleCreatedByOtherProcessWasUsed = |
| michael@0 | 124 | aOther.mHandleCreatedByOtherProcessWasUsed; |
| michael@0 | 125 | mHandle = aOther.PlatformHandle(); |
| michael@0 | 126 | } else { |
| michael@0 | 127 | DuplicateInCurrentProcess(aOther.PlatformHandle()); |
| michael@0 | 128 | mHandleCreatedByOtherProcess = false; |
| michael@0 | 129 | mHandleCreatedByOtherProcessWasUsed = false; |
| michael@0 | 130 | } |
| michael@0 | 131 | } |
| michael@0 | 132 | |
| michael@0 | 133 | static bool |
| michael@0 | 134 | IsValid(PlatformHandleType aHandle); |
| michael@0 | 135 | |
| michael@0 | 136 | void |
| michael@0 | 137 | DuplicateInCurrentProcess(PlatformHandleType aHandle); |
| michael@0 | 138 | |
| michael@0 | 139 | void |
| michael@0 | 140 | CloseCurrentProcessHandle(); |
| michael@0 | 141 | |
| michael@0 | 142 | PlatformHandleType mHandle; |
| michael@0 | 143 | |
| michael@0 | 144 | // If this is true then this instance is created by IPDL to ferry a handle to |
| michael@0 | 145 | // its eventual consumer and we never close the handle. If this is false then |
| michael@0 | 146 | // we are a RAII wrapper around the handle and we close the handle on |
| michael@0 | 147 | // destruction. |
| michael@0 | 148 | bool mHandleCreatedByOtherProcess; |
| michael@0 | 149 | |
| michael@0 | 150 | // This is to ensure that we don't leak the handle (which is only possible |
| michael@0 | 151 | // when we're in the receiving process). |
| michael@0 | 152 | mutable DebugOnly<bool> mHandleCreatedByOtherProcessWasUsed; |
| michael@0 | 153 | }; |
| michael@0 | 154 | |
| michael@0 | 155 | } // namespace ipc |
| michael@0 | 156 | } // namespace mozilla |
| michael@0 | 157 | |
| michael@0 | 158 | #endif // mozilla_ipc_FileDescriptor_h |
