1 /*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 //
18 // Shared file mapping class.
19 //
20
21 #define LOG_TAG "filemap"
22
23 #include <utils/FileMap.h>
24 #include <utils/Log.h>
25
26 #if defined(__MINGW32__) && !defined(__USE_MINGW_ANSI_STDIO)
27 # define PRId32 "I32d"
28 # define PRIx32 "I32x"
29 # define PRId64 "I64d"
30 #else
31 #include <inttypes.h>
32 #endif
33 #include <stdio.h>
34 #include <stdlib.h>
35
36 #if !defined(__MINGW32__)
37 #include <sys/mman.h>
38 #endif
39
40 #include <string.h>
41 #include <memory.h>
42 #include <errno.h>
43 #include <assert.h>
44
45 using namespace android;
46
47 /*static*/ long FileMap::mPageSize = -1;
48
49 // Constructor. Create an empty object.
FileMap(void)50 FileMap::FileMap(void)
51 : mFileName(NULL), mBasePtr(NULL), mBaseLength(0),
52 mDataPtr(NULL), mDataLength(0)
53 {
54 }
55
56 // Destructor.
~FileMap(void)57 FileMap::~FileMap(void)
58 {
59 if (mFileName != NULL) {
60 free(mFileName);
61 }
62 #if defined(__MINGW32__)
63 if (mBasePtr && UnmapViewOfFile(mBasePtr) == 0) {
64 ALOGD("UnmapViewOfFile(%p) failed, error = %" PRId32 "\n", mBasePtr,
65 GetLastError() );
66 }
67 if (mFileMapping != INVALID_HANDLE_VALUE) {
68 CloseHandle(mFileMapping);
69 }
70 #else
71 if (mBasePtr && munmap(mBasePtr, mBaseLength) != 0) {
72 ALOGD("munmap(%p, %zu) failed\n", mBasePtr, mBaseLength);
73 }
74 #endif
75 }
76
77
78 // Create a new mapping on an open file.
79 //
80 // Closing the file descriptor does not unmap the pages, so we don't
81 // claim ownership of the fd.
82 //
83 // Returns "false" on failure.
create(const char * origFileName,int fd,off64_t offset,size_t length,bool readOnly)84 bool FileMap::create(const char* origFileName, int fd, off64_t offset, size_t length,
85 bool readOnly)
86 {
87 #if defined(__MINGW32__)
88 int adjust;
89 off64_t adjOffset;
90 size_t adjLength;
91
92 if (mPageSize == -1) {
93 SYSTEM_INFO si;
94
95 GetSystemInfo( &si );
96 mPageSize = si.dwAllocationGranularity;
97 }
98
99 DWORD protect = readOnly ? PAGE_READONLY : PAGE_READWRITE;
100
101 mFileHandle = (HANDLE) _get_osfhandle(fd);
102 mFileMapping = CreateFileMapping( mFileHandle, NULL, protect, 0, 0, NULL);
103 if (mFileMapping == NULL) {
104 ALOGE("CreateFileMapping(%p, %" PRIx32 ") failed with error %" PRId32 "\n",
105 mFileHandle, protect, GetLastError() );
106 return false;
107 }
108
109 adjust = offset % mPageSize;
110 adjOffset = offset - adjust;
111 adjLength = length + adjust;
112
113 mBasePtr = MapViewOfFile( mFileMapping,
114 readOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS,
115 0,
116 (DWORD)(adjOffset),
117 adjLength );
118 if (mBasePtr == NULL) {
119 ALOGE("MapViewOfFile(%" PRId64 ", %zu) failed with error %" PRId32 "\n",
120 adjOffset, adjLength, GetLastError() );
121 CloseHandle(mFileMapping);
122 mFileMapping = INVALID_HANDLE_VALUE;
123 return false;
124 }
125 #else // !defined(__MINGW32__)
126 int prot, flags, adjust;
127 off64_t adjOffset;
128 size_t adjLength;
129
130 void* ptr;
131
132 assert(fd >= 0);
133 assert(offset >= 0);
134 assert(length > 0);
135
136 // init on first use
137 if (mPageSize == -1) {
138 mPageSize = sysconf(_SC_PAGESIZE);
139 if (mPageSize == -1) {
140 ALOGE("could not get _SC_PAGESIZE\n");
141 return false;
142 }
143 }
144
145 adjust = offset % mPageSize;
146 adjOffset = offset - adjust;
147 adjLength = length + adjust;
148
149 flags = MAP_SHARED;
150 prot = PROT_READ;
151 if (!readOnly)
152 prot |= PROT_WRITE;
153
154 ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset);
155 if (ptr == MAP_FAILED) {
156 ALOGE("mmap(%lld,%zu) failed: %s\n",
157 (long long)adjOffset, adjLength, strerror(errno));
158 return false;
159 }
160 mBasePtr = ptr;
161 #endif // !defined(__MINGW32__)
162
163 mFileName = origFileName != NULL ? strdup(origFileName) : NULL;
164 mBaseLength = adjLength;
165 mDataOffset = offset;
166 mDataPtr = (char*) mBasePtr + adjust;
167 mDataLength = length;
168
169 assert(mBasePtr != NULL);
170
171 ALOGV("MAP: base %p/%zu data %p/%zu\n",
172 mBasePtr, mBaseLength, mDataPtr, mDataLength);
173
174 return true;
175 }
176
177 // Provide guidance to the system.
178 #if !defined(_WIN32)
advise(MapAdvice advice)179 int FileMap::advise(MapAdvice advice)
180 {
181 int cc, sysAdvice;
182
183 switch (advice) {
184 case NORMAL: sysAdvice = MADV_NORMAL; break;
185 case RANDOM: sysAdvice = MADV_RANDOM; break;
186 case SEQUENTIAL: sysAdvice = MADV_SEQUENTIAL; break;
187 case WILLNEED: sysAdvice = MADV_WILLNEED; break;
188 case DONTNEED: sysAdvice = MADV_DONTNEED; break;
189 default:
190 assert(false);
191 return -1;
192 }
193
194 cc = madvise(mBasePtr, mBaseLength, sysAdvice);
195 if (cc != 0)
196 ALOGW("madvise(%d) failed: %s\n", sysAdvice, strerror(errno));
197 return cc;
198 }
199
200 #else
advise(MapAdvice)201 int FileMap::advise(MapAdvice /* advice */)
202 {
203 return -1;
204 }
205 #endif
206