OLD | NEW |
1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "base/memory/shared_memory.h" | 5 #include "base/memory/shared_memory.h" |
6 | 6 |
7 #include <errno.h> | 7 #include <errno.h> |
8 #include <fcntl.h> | 8 #include <fcntl.h> |
9 #include <stddef.h> | 9 #include <stddef.h> |
10 #include <sys/mman.h> | 10 #include <sys/mman.h> |
(...skipping 354 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
365 *path = temp_dir.AppendASCII(name_base + ".shmem." + mem_name); | 365 *path = temp_dir.AppendASCII(name_base + ".shmem." + mem_name); |
366 return true; | 366 return true; |
367 } | 367 } |
368 #endif // !defined(OS_ANDROID) | 368 #endif // !defined(OS_ANDROID) |
369 | 369 |
370 SharedMemoryHandle SharedMemory::GetReadOnlyHandle() { | 370 SharedMemoryHandle SharedMemory::GetReadOnlyHandle() { |
371 CHECK(readonly_shm_.IsValid()); | 371 CHECK(readonly_shm_.IsValid()); |
372 return readonly_shm_.Duplicate(); | 372 return readonly_shm_.Duplicate(); |
373 } | 373 } |
374 | 374 |
375 bool SharedMemory::GetUniqueId(SharedMemory::UniqueId* id) const { | |
376 // This function is called just after mmap. fstat is a system call that might | |
377 // cause I/O. It's safe to call fstat here because mmap for shared memory is | |
378 // called in two cases: | |
379 // 1) To handle file-mapped memory | |
380 // 2) To handle annonymous shared memory | |
381 // In 1), I/O is already permitted. In 2), the backend is on page cache and | |
382 // fstat doesn't cause I/O access to the disk. See the discussion at | |
383 // crbug.com/604726#c41. | |
384 base::ThreadRestrictions::ScopedAllowIO allow_io; | |
385 struct stat file_stat; | |
386 if (HANDLE_EINTR( | |
387 ::fstat(static_cast<int>(handle().GetHandle()), &file_stat)) != 0) | |
388 return false; | |
389 id->first = file_stat.st_dev; | |
390 id->second = file_stat.st_ino; | |
391 return true; | |
392 } | |
393 | |
394 } // namespace base | 375 } // namespace base |
OLD | NEW |