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/system/raw_shared_buffer.h"
6
7 #include <windows.h>
8
9 #include <limits>
10
11 #include "base/logging.h"
12 #include "base/sys_info.h"
13 #include "mojo/embedder/platform_handle.h"
14 #include "mojo/embedder/scoped_platform_handle.h"
15
16 namespace mojo {
17 namespace system {
18
19 // RawSharedBuffer -------------------------------------------------------------
20
Init()21 bool RawSharedBuffer::Init() {
22 DCHECK(!handle_.is_valid());
23
24 // TODO(vtl): Currently, we only support mapping up to 2^32-1 bytes.
25 if (static_cast<uint64_t>(num_bytes_) >
26 static_cast<uint64_t>(std::numeric_limits<DWORD>::max())) {
27 return false;
28 }
29
30 // IMPORTANT NOTE: Unnamed objects are NOT SECURABLE. Thus if we ever want to
31 // share read-only to other processes, we'll have to name our file mapping
32 // object.
33 // TODO(vtl): Unlike |base::SharedMemory|, we don't round up the size (to a
34 // multiple of 64 KB). This may cause problems with NaCl. Cross this bridge
35 // when we get there. crbug.com/210609
36 handle_.reset(embedder::PlatformHandle(CreateFileMapping(
37 INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0,
38 static_cast<DWORD>(num_bytes_), NULL)));
39 if (!handle_.is_valid()) {
40 PLOG(ERROR) << "CreateFileMapping";
41 return false;
42 }
43
44 return true;
45 }
46
InitFromPlatformHandle(embedder::ScopedPlatformHandle platform_handle)47 bool RawSharedBuffer::InitFromPlatformHandle(
48 embedder::ScopedPlatformHandle platform_handle) {
49 DCHECK(!handle_.is_valid());
50
51 // TODO(vtl): Implement.
52 NOTIMPLEMENTED();
53 return false;
54 }
55
MapImpl(size_t offset,size_t length)56 scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::MapImpl(size_t offset,
57 size_t length) {
58 size_t offset_rounding = offset % base::SysInfo::VMAllocationGranularity();
59 size_t real_offset = offset - offset_rounding;
60 size_t real_length = length + offset_rounding;
61
62 // This should hold (since we checked |num_bytes| versus the maximum value of
63 // |off_t| on creation, but it never hurts to be paranoid.
64 DCHECK_LE(static_cast<uint64_t>(real_offset),
65 static_cast<uint64_t>(std::numeric_limits<DWORD>::max()));
66
67 void* real_base = MapViewOfFile(
68 handle_.get().handle, FILE_MAP_READ | FILE_MAP_WRITE, 0,
69 static_cast<DWORD>(real_offset), real_length);
70 if (!real_base) {
71 PLOG(ERROR) << "MapViewOfFile";
72 return scoped_ptr<RawSharedBufferMapping>();
73 }
74
75 void* base = static_cast<char*>(real_base) + offset_rounding;
76 return make_scoped_ptr(
77 new RawSharedBufferMapping(base, length, real_base, real_length));
78 }
79
80 // RawSharedBufferMapping ------------------------------------------------------
81
Unmap()82 void RawSharedBufferMapping::Unmap() {
83 BOOL result = UnmapViewOfFile(real_base_);
84 PLOG_IF(ERROR, !result) << "UnmapViewOfFile";
85 }
86
87 } // namespace system
88 } // namespace mojo
89