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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "mojo/edk/system/handle_table.h" | |
| 6 | |
| 7 #include "base/logging.h" | |
| 8 #include "base/macros.h" | |
| 9 #include "mojo/edk/system/constants.h" | |
| 10 #include "mojo/edk/system/dispatcher.h" | |
| 11 | |
| 12 namespace mojo { | |
| 13 namespace system { | |
| 14 | |
| 15 HandleTable::Entry::Entry() : busy(false) { | |
| 16 } | |
| 17 | |
| 18 HandleTable::Entry::Entry(const scoped_refptr<Dispatcher>& dispatcher) | |
| 19 : dispatcher(dispatcher), busy(false) { | |
| 20 } | |
| 21 | |
| 22 HandleTable::Entry::~Entry() { | |
| 23 DCHECK(!busy); | |
| 24 } | |
| 25 | |
| 26 HandleTable::HandleTable() : next_handle_(MOJO_HANDLE_INVALID + 1) { | |
| 27 } | |
| 28 | |
| 29 HandleTable::~HandleTable() { | |
| 30 // This should usually not be reached (the only instance should be owned by | |
| 31 // the singleton |Core|, which lives forever), except in tests. | |
| 32 } | |
| 33 | |
| 34 Dispatcher* HandleTable::GetDispatcher(MojoHandle handle) { | |
| 35 DCHECK_NE(handle, MOJO_HANDLE_INVALID); | |
| 36 | |
| 37 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handle); | |
| 38 if (it == handle_to_entry_map_.end()) | |
| 39 return nullptr; | |
| 40 return it->second.dispatcher.get(); | |
| 41 } | |
| 42 | |
| 43 MojoResult HandleTable::GetAndRemoveDispatcher( | |
| 44 MojoHandle handle, | |
| 45 scoped_refptr<Dispatcher>* dispatcher) { | |
| 46 DCHECK_NE(handle, MOJO_HANDLE_INVALID); | |
| 47 DCHECK(dispatcher); | |
| 48 | |
| 49 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handle); | |
| 50 if (it == handle_to_entry_map_.end()) | |
| 51 return MOJO_RESULT_INVALID_ARGUMENT; | |
| 52 if (it->second.busy) | |
| 53 return MOJO_RESULT_BUSY; | |
| 54 *dispatcher = it->second.dispatcher; | |
| 55 handle_to_entry_map_.erase(it); | |
| 56 | |
| 57 return MOJO_RESULT_OK; | |
| 58 } | |
| 59 | |
| 60 MojoHandle HandleTable::AddDispatcher( | |
| 61 const scoped_refptr<Dispatcher>& dispatcher) { | |
| 62 if (handle_to_entry_map_.size() >= kMaxHandleTableSize) | |
| 63 return MOJO_HANDLE_INVALID; | |
| 64 return AddDispatcherNoSizeCheck(dispatcher); | |
| 65 } | |
| 66 | |
| 67 std::pair<MojoHandle, MojoHandle> HandleTable::AddDispatcherPair( | |
| 68 const scoped_refptr<Dispatcher>& dispatcher0, | |
| 69 const scoped_refptr<Dispatcher>& dispatcher1) { | |
| 70 if (handle_to_entry_map_.size() + 1 >= kMaxHandleTableSize) | |
| 71 return std::make_pair(MOJO_HANDLE_INVALID, MOJO_HANDLE_INVALID); | |
| 72 return std::make_pair(AddDispatcherNoSizeCheck(dispatcher0), | |
| 73 AddDispatcherNoSizeCheck(dispatcher1)); | |
| 74 } | |
| 75 | |
| 76 bool HandleTable::AddDispatcherVector(const DispatcherVector& dispatchers, | |
| 77 MojoHandle* handles) { | |
| 78 DCHECK_LE(dispatchers.size(), kMaxMessageNumHandles); | |
| 79 DCHECK(handles); | |
| 80 // TODO(vtl): |std::numeric_limits<size_t>::max()| isn't a compile-time | |
| 81 // expression in C++03. | |
| 82 static_assert( | |
| 83 static_cast<uint64_t>(kMaxHandleTableSize) + kMaxMessageNumHandles < | |
| 84 (sizeof(size_t) == 8 ? kuint64max | |
| 85 : static_cast<uint64_t>(kuint32max)), | |
| 86 "Addition may overflow"); | |
| 87 | |
| 88 if (handle_to_entry_map_.size() + dispatchers.size() > kMaxHandleTableSize) | |
| 89 return false; | |
| 90 | |
| 91 for (size_t i = 0; i < dispatchers.size(); i++) { | |
| 92 if (dispatchers[i].get()) { | |
| 93 handles[i] = AddDispatcherNoSizeCheck(dispatchers[i]); | |
| 94 } else { | |
| 95 LOG(WARNING) << "Invalid dispatcher at index " << i; | |
| 96 handles[i] = MOJO_HANDLE_INVALID; | |
| 97 } | |
| 98 } | |
| 99 return true; | |
| 100 } | |
| 101 | |
| 102 MojoResult HandleTable::MarkBusyAndStartTransport( | |
| 103 MojoHandle disallowed_handle, | |
| 104 const MojoHandle* handles, | |
| 105 uint32_t num_handles, | |
| 106 std::vector<DispatcherTransport>* transports) { | |
| 107 DCHECK_NE(disallowed_handle, MOJO_HANDLE_INVALID); | |
| 108 DCHECK(handles); | |
| 109 DCHECK_LE(num_handles, kMaxMessageNumHandles); | |
| 110 DCHECK(transports); | |
| 111 DCHECK_EQ(transports->size(), num_handles); | |
| 112 | |
| 113 std::vector<Entry*> entries(num_handles); | |
| 114 | |
| 115 // First verify all the handles and get their dispatchers. | |
| 116 uint32_t i; | |
| 117 MojoResult error_result = MOJO_RESULT_INTERNAL; | |
| 118 for (i = 0; i < num_handles; i++) { | |
| 119 // Sending your own handle is not allowed (and, for consistency, returns | |
| 120 // "busy"). | |
| 121 if (handles[i] == disallowed_handle) { | |
| 122 error_result = MOJO_RESULT_BUSY; | |
| 123 break; | |
| 124 } | |
| 125 | |
| 126 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 127 if (it == handle_to_entry_map_.end()) { | |
| 128 error_result = MOJO_RESULT_INVALID_ARGUMENT; | |
| 129 break; | |
| 130 } | |
| 131 | |
| 132 entries[i] = &it->second; | |
| 133 if (entries[i]->busy) { | |
| 134 error_result = MOJO_RESULT_BUSY; | |
| 135 break; | |
| 136 } | |
| 137 // Note: By marking the handle as busy here, we're also preventing the | |
| 138 // same handle from being sent multiple times in the same message. | |
| 139 entries[i]->busy = true; | |
| 140 | |
| 141 // Try to start the transport. | |
| 142 DispatcherTransport transport = | |
| 143 Dispatcher::HandleTableAccess::TryStartTransport( | |
| 144 entries[i]->dispatcher.get()); | |
| 145 if (!transport.is_valid()) { | |
| 146 // Only log for Debug builds, since this is not a problem with the system | |
| 147 // code, but with user code. | |
| 148 DLOG(WARNING) << "Likely race condition in user code detected: attempt " | |
| 149 "to transfer handle " << handles[i] | |
| 150 << " while it is in use on a different thread"; | |
| 151 | |
| 152 // Unset the busy flag (since it won't be unset below). | |
| 153 entries[i]->busy = false; | |
| 154 error_result = MOJO_RESULT_BUSY; | |
| 155 break; | |
| 156 } | |
| 157 | |
| 158 // Check if the dispatcher is busy (e.g., in a two-phase read/write). | |
| 159 // (Note that this must be done after the dispatcher's lock is acquired.) | |
| 160 if (transport.IsBusy()) { | |
| 161 // Unset the busy flag and end the transport (since it won't be done | |
| 162 // below). | |
| 163 entries[i]->busy = false; | |
| 164 transport.End(); | |
| 165 error_result = MOJO_RESULT_BUSY; | |
| 166 break; | |
| 167 } | |
| 168 | |
| 169 // Hang on to the transport (which we'll need to end the transport). | |
| 170 (*transports)[i] = transport; | |
| 171 } | |
| 172 if (i < num_handles) { | |
| 173 DCHECK_NE(error_result, MOJO_RESULT_INTERNAL); | |
| 174 | |
| 175 // Unset the busy flags and release the locks. | |
| 176 for (uint32_t j = 0; j < i; j++) { | |
| 177 DCHECK(entries[j]->busy); | |
| 178 entries[j]->busy = false; | |
| 179 (*transports)[j].End(); | |
| 180 } | |
| 181 return error_result; | |
| 182 } | |
| 183 | |
| 184 return MOJO_RESULT_OK; | |
| 185 } | |
| 186 | |
| 187 MojoHandle HandleTable::AddDispatcherNoSizeCheck( | |
| 188 const scoped_refptr<Dispatcher>& dispatcher) { | |
| 189 DCHECK(dispatcher.get()); | |
| 190 DCHECK_LT(handle_to_entry_map_.size(), kMaxHandleTableSize); | |
| 191 DCHECK_NE(next_handle_, MOJO_HANDLE_INVALID); | |
| 192 | |
| 193 // TODO(vtl): Maybe we want to do something different/smarter. (Or maybe try | |
| 194 // assigning randomly?) | |
| 195 while (handle_to_entry_map_.find(next_handle_) != | |
| 196 handle_to_entry_map_.end()) { | |
| 197 next_handle_++; | |
| 198 if (next_handle_ == MOJO_HANDLE_INVALID) | |
| 199 next_handle_++; | |
| 200 } | |
| 201 | |
| 202 MojoHandle new_handle = next_handle_; | |
| 203 handle_to_entry_map_[new_handle] = Entry(dispatcher); | |
| 204 | |
| 205 next_handle_++; | |
| 206 if (next_handle_ == MOJO_HANDLE_INVALID) | |
| 207 next_handle_++; | |
| 208 | |
| 209 return new_handle; | |
| 210 } | |
| 211 | |
| 212 void HandleTable::RemoveBusyHandles(const MojoHandle* handles, | |
| 213 uint32_t num_handles) { | |
| 214 DCHECK(handles); | |
| 215 DCHECK_LE(num_handles, kMaxMessageNumHandles); | |
| 216 | |
| 217 for (uint32_t i = 0; i < num_handles; i++) { | |
| 218 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 219 DCHECK(it != handle_to_entry_map_.end()); | |
| 220 DCHECK(it->second.busy); | |
| 221 it->second.busy = false; // For the sake of a |DCHECK()|. | |
| 222 handle_to_entry_map_.erase(it); | |
| 223 } | |
| 224 } | |
| 225 | |
| 226 void HandleTable::RestoreBusyHandles(const MojoHandle* handles, | |
| 227 uint32_t num_handles) { | |
| 228 DCHECK(handles); | |
| 229 DCHECK_LE(num_handles, kMaxMessageNumHandles); | |
| 230 | |
| 231 for (uint32_t i = 0; i < num_handles; i++) { | |
| 232 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 233 DCHECK(it != handle_to_entry_map_.end()); | |
| 234 DCHECK(it->second.busy); | |
| 235 it->second.busy = false; | |
| 236 } | |
| 237 } | |
| 238 | |
| 239 } // namespace system | |
| 240 } // namespace mojo | |
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Chromium Code Reviews
Issue 623883002:
Revert "Move mojo edk into mojo/edk" (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master