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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 <limits> | |
| 8 #include "base/logging.h" | |
| 9 #include "base/macros.h" | |
| 10 #include "mojo/edk/system/configuration.h" | |
| 11 #include "mojo/edk/system/dispatcher.h" | |
| 12 | |
| 13 namespace mojo { | |
| 14 namespace system { | |
| 15 | |
| 16 HandleTable::Entry::Entry() : busy(false) { | |
| 17 } | |
| 18 | |
| 19 HandleTable::Entry::Entry(const scoped_refptr<Dispatcher>& dispatcher) | |
| 20 : dispatcher(dispatcher), busy(false) { | |
| 21 } | |
| 22 | |
| 23 HandleTable::Entry::~Entry() { | |
| 24 DCHECK(!busy); | |
| 25 } | |
| 26 | |
| 27 HandleTable::HandleTable() : next_handle_(MOJO_HANDLE_INVALID + 1) { | |
| 28 } | |
| 29 | |
| 30 HandleTable::~HandleTable() { | |
| 31 // This should usually not be reached (the only instance should be owned by | |
| 32 // the singleton |Core|, which lives forever), except in tests. | |
| 33 } | |
| 34 | |
| 35 Dispatcher* HandleTable::GetDispatcher(MojoHandle handle) { | |
| 36 DCHECK_NE(handle, MOJO_HANDLE_INVALID); | |
| 37 | |
| 38 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handle); | |
| 39 if (it == handle_to_entry_map_.end()) | |
| 40 return nullptr; | |
| 41 return it->second.dispatcher.get(); | |
| 42 } | |
| 43 | |
| 44 MojoResult HandleTable::GetAndRemoveDispatcher( | |
| 45 MojoHandle handle, | |
| 46 scoped_refptr<Dispatcher>* dispatcher) { | |
| 47 DCHECK_NE(handle, MOJO_HANDLE_INVALID); | |
| 48 DCHECK(dispatcher); | |
| 49 | |
| 50 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handle); | |
| 51 if (it == handle_to_entry_map_.end()) | |
| 52 return MOJO_RESULT_INVALID_ARGUMENT; | |
| 53 if (it->second.busy) | |
| 54 return MOJO_RESULT_BUSY; | |
| 55 *dispatcher = it->second.dispatcher; | |
| 56 handle_to_entry_map_.erase(it); | |
| 57 | |
| 58 return MOJO_RESULT_OK; | |
| 59 } | |
| 60 | |
| 61 MojoHandle HandleTable::AddDispatcher( | |
| 62 const scoped_refptr<Dispatcher>& dispatcher) { | |
| 63 if (handle_to_entry_map_.size() >= GetConfiguration().max_handle_table_size) | |
| 64 return MOJO_HANDLE_INVALID; | |
| 65 return AddDispatcherNoSizeCheck(dispatcher); | |
| 66 } | |
| 67 | |
| 68 std::pair<MojoHandle, MojoHandle> HandleTable::AddDispatcherPair( | |
| 69 const scoped_refptr<Dispatcher>& dispatcher0, | |
| 70 const scoped_refptr<Dispatcher>& dispatcher1) { | |
| 71 if (handle_to_entry_map_.size() + 1 >= | |
| 72 GetConfiguration().max_handle_table_size) | |
| 73 return std::make_pair(MOJO_HANDLE_INVALID, MOJO_HANDLE_INVALID); | |
| 74 return std::make_pair(AddDispatcherNoSizeCheck(dispatcher0), | |
| 75 AddDispatcherNoSizeCheck(dispatcher1)); | |
| 76 } | |
| 77 | |
| 78 bool HandleTable::AddDispatcherVector(const DispatcherVector& dispatchers, | |
| 79 MojoHandle* handles) { | |
| 80 size_t max_message_num_handles = GetConfiguration().max_message_num_handles; | |
| 81 size_t max_handle_table_size = GetConfiguration().max_handle_table_size; | |
| 82 | |
| 83 DCHECK_LE(dispatchers.size(), max_message_num_handles); | |
| 84 DCHECK(handles); | |
| 85 DCHECK_LT( | |
| 86 static_cast<uint64_t>(max_handle_table_size) + max_message_num_handles, | |
| 87 std::numeric_limits<size_t>::max()) | |
| 88 << "Addition may overflow"; | |
| 89 | |
| 90 if (handle_to_entry_map_.size() + dispatchers.size() > max_handle_table_size) | |
| 91 return false; | |
| 92 | |
| 93 for (size_t i = 0; i < dispatchers.size(); i++) { | |
| 94 if (dispatchers[i]) { | |
| 95 handles[i] = AddDispatcherNoSizeCheck(dispatchers[i]); | |
| 96 } else { | |
| 97 LOG(WARNING) << "Invalid dispatcher at index " << i; | |
| 98 handles[i] = MOJO_HANDLE_INVALID; | |
| 99 } | |
| 100 } | |
| 101 return true; | |
| 102 } | |
| 103 | |
| 104 MojoResult HandleTable::MarkBusyAndStartTransport( | |
| 105 MojoHandle disallowed_handle, | |
| 106 const MojoHandle* handles, | |
| 107 uint32_t num_handles, | |
| 108 std::vector<DispatcherTransport>* transports) { | |
| 109 DCHECK_NE(disallowed_handle, MOJO_HANDLE_INVALID); | |
| 110 DCHECK(handles); | |
| 111 DCHECK_LE(num_handles, GetConfiguration().max_message_num_handles); | |
| 112 DCHECK(transports); | |
| 113 DCHECK_EQ(transports->size(), num_handles); | |
| 114 | |
| 115 std::vector<Entry*> entries(num_handles); | |
| 116 | |
| 117 // First verify all the handles and get their dispatchers. | |
| 118 uint32_t i; | |
| 119 MojoResult error_result = MOJO_RESULT_INTERNAL; | |
| 120 for (i = 0; i < num_handles; i++) { | |
| 121 // Sending your own handle is not allowed (and, for consistency, returns | |
| 122 // "busy"). | |
| 123 if (handles[i] == disallowed_handle) { | |
| 124 error_result = MOJO_RESULT_BUSY; | |
| 125 break; | |
| 126 } | |
| 127 | |
| 128 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 129 if (it == handle_to_entry_map_.end()) { | |
| 130 error_result = MOJO_RESULT_INVALID_ARGUMENT; | |
| 131 break; | |
| 132 } | |
| 133 | |
| 134 entries[i] = &it->second; | |
| 135 if (entries[i]->busy) { | |
| 136 error_result = MOJO_RESULT_BUSY; | |
| 137 break; | |
| 138 } | |
| 139 // Note: By marking the handle as busy here, we're also preventing the | |
| 140 // same handle from being sent multiple times in the same message. | |
| 141 entries[i]->busy = true; | |
| 142 | |
| 143 // Try to start the transport. | |
| 144 DispatcherTransport transport = | |
| 145 Dispatcher::HandleTableAccess::TryStartTransport( | |
| 146 entries[i]->dispatcher.get()); | |
| 147 if (!transport.is_valid()) { | |
| 148 // Only log for Debug builds, since this is not a problem with the system | |
| 149 // code, but with user code. | |
| 150 DLOG(WARNING) << "Likely race condition in user code detected: attempt " | |
| 151 "to transfer handle " << handles[i] | |
| 152 << " while it is in use on a different thread"; | |
| 153 | |
| 154 // Unset the busy flag (since it won't be unset below). | |
| 155 entries[i]->busy = false; | |
| 156 error_result = MOJO_RESULT_BUSY; | |
| 157 break; | |
| 158 } | |
| 159 | |
| 160 // Check if the dispatcher is busy (e.g., in a two-phase read/write). | |
| 161 // (Note that this must be done after the dispatcher's lock is acquired.) | |
| 162 if (transport.IsBusy()) { | |
| 163 // Unset the busy flag and end the transport (since it won't be done | |
| 164 // below). | |
| 165 entries[i]->busy = false; | |
| 166 transport.End(); | |
| 167 error_result = MOJO_RESULT_BUSY; | |
| 168 break; | |
| 169 } | |
| 170 | |
| 171 // Hang on to the transport (which we'll need to end the transport). | |
| 172 (*transports)[i] = transport; | |
| 173 } | |
| 174 if (i < num_handles) { | |
| 175 DCHECK_NE(error_result, MOJO_RESULT_INTERNAL); | |
| 176 | |
| 177 // Unset the busy flags and release the locks. | |
| 178 for (uint32_t j = 0; j < i; j++) { | |
| 179 DCHECK(entries[j]->busy); | |
| 180 entries[j]->busy = false; | |
| 181 (*transports)[j].End(); | |
| 182 } | |
| 183 return error_result; | |
| 184 } | |
| 185 | |
| 186 return MOJO_RESULT_OK; | |
| 187 } | |
| 188 | |
| 189 MojoHandle HandleTable::AddDispatcherNoSizeCheck( | |
| 190 const scoped_refptr<Dispatcher>& dispatcher) { | |
| 191 DCHECK(dispatcher); | |
| 192 DCHECK_LT(handle_to_entry_map_.size(), | |
| 193 GetConfiguration().max_handle_table_size); | |
| 194 DCHECK_NE(next_handle_, MOJO_HANDLE_INVALID); | |
| 195 | |
| 196 // TODO(vtl): Maybe we want to do something different/smarter. (Or maybe try | |
| 197 // assigning randomly?) | |
| 198 while (handle_to_entry_map_.find(next_handle_) != | |
| 199 handle_to_entry_map_.end()) { | |
| 200 next_handle_++; | |
| 201 if (next_handle_ == MOJO_HANDLE_INVALID) | |
| 202 next_handle_++; | |
| 203 } | |
| 204 | |
| 205 MojoHandle new_handle = next_handle_; | |
| 206 handle_to_entry_map_[new_handle] = Entry(dispatcher); | |
| 207 | |
| 208 next_handle_++; | |
| 209 if (next_handle_ == MOJO_HANDLE_INVALID) | |
| 210 next_handle_++; | |
| 211 | |
| 212 return new_handle; | |
| 213 } | |
| 214 | |
| 215 void HandleTable::RemoveBusyHandles(const MojoHandle* handles, | |
| 216 uint32_t num_handles) { | |
| 217 DCHECK(handles); | |
| 218 DCHECK_LE(num_handles, GetConfiguration().max_message_num_handles); | |
| 219 | |
| 220 for (uint32_t i = 0; i < num_handles; i++) { | |
| 221 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 222 DCHECK(it != handle_to_entry_map_.end()); | |
| 223 DCHECK(it->second.busy); | |
| 224 it->second.busy = false; // For the sake of a |DCHECK()|. | |
| 225 handle_to_entry_map_.erase(it); | |
| 226 } | |
| 227 } | |
| 228 | |
| 229 void HandleTable::RestoreBusyHandles(const MojoHandle* handles, | |
| 230 uint32_t num_handles) { | |
| 231 DCHECK(handles); | |
| 232 DCHECK_LE(num_handles, GetConfiguration().max_message_num_handles); | |
| 233 | |
| 234 for (uint32_t i = 0; i < num_handles; i++) { | |
| 235 HandleToEntryMap::iterator it = handle_to_entry_map_.find(handles[i]); | |
| 236 DCHECK(it != handle_to_entry_map_.end()); | |
| 237 DCHECK(it->second.busy); | |
| 238 it->second.busy = false; | |
| 239 } | |
| 240 } | |
| 241 | |
| 242 } // namespace system | |
| 243 } // namespace mojo | |
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Chromium Code Reviews
Issue 814543006:
Move //mojo/{public, edk} underneath //third_party (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master