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 #include <stdio.h> 27 #include <stdlib.h> 28 29 #ifdef HAVE_POSIX_FILEMAP 30 #include <sys/mman.h> 31 #endif 32 33 #include <string.h> 34 #include <memory.h> 35 #include <errno.h> 36 #include <assert.h> 37 38 using namespace android; 39 40 /*static*/ long FileMap::mPageSize = -1; 41 42 43 /* 44 * Constructor. Create an empty object. 45 */ 46 FileMap::FileMap(void) 47 : mRefCount(1), mFileName(NULL), mBasePtr(NULL), mBaseLength(0), 48 mDataPtr(NULL), mDataLength(0) 49 { 50 } 51 52 /* 53 * Destructor. 54 */ 55 FileMap::~FileMap(void) 56 { 57 assert(mRefCount == 0); 58 59 //printf("+++ removing FileMap %p %u\n", mDataPtr, mDataLength); 60 61 mRefCount = -100; // help catch double-free 62 if (mFileName != NULL) { 63 free(mFileName); 64 } 65 #ifdef HAVE_POSIX_FILEMAP 66 if (munmap(mBasePtr, mBaseLength) != 0) { 67 LOGD("munmap(%p, %d) failed\n", mBasePtr, (int) mBaseLength); 68 } 69 #endif 70 #ifdef HAVE_WIN32_FILEMAP 71 if ( UnmapViewOfFile(mBasePtr) == 0) { 72 LOGD("UnmapViewOfFile(%p) failed, error = %ld\n", mBasePtr, 73 GetLastError() ); 74 } 75 CloseHandle(mFileMapping); 76 CloseHandle(mFileHandle); 77 #endif 78 } 79 80 81 /* 82 * Create a new mapping on an open file. 83 * 84 * Closing the file descriptor does not unmap the pages, so we don't 85 * claim ownership of the fd. 86 * 87 * Returns "false" on failure. 88 */ 89 bool FileMap::create(const char* origFileName, int fd, off_t offset, size_t length, bool readOnly) 90 { 91 #ifdef HAVE_WIN32_FILEMAP 92 int adjust; 93 off_t adjOffset; 94 size_t adjLength; 95 96 if (mPageSize == -1) { 97 SYSTEM_INFO si; 98 99 GetSystemInfo( &si ); 100 mPageSize = si.dwAllocationGranularity; 101 } 102 103 DWORD protect = readOnly ? PAGE_READONLY : PAGE_READWRITE; 104 105 mFileHandle = (HANDLE) _get_osfhandle(fd); 106 mFileMapping = CreateFileMapping( mFileHandle, NULL, protect, 0, 0, NULL); 107 if (mFileMapping == NULL) { 108 LOGE("CreateFileMapping(%p, %lx) failed with error %ld\n", 109 mFileHandle, protect, GetLastError() ); 110 return false; 111 } 112 113 adjust = offset % mPageSize; 114 adjOffset = offset - adjust; 115 adjLength = length + adjust; 116 117 mBasePtr = MapViewOfFile( mFileMapping, 118 readOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS, 119 0, 120 (DWORD)(adjOffset), 121 adjLength ); 122 if (mBasePtr == NULL) { 123 LOGE("MapViewOfFile(%ld, %ld) failed with error %ld\n", 124 adjOffset, adjLength, GetLastError() ); 125 CloseHandle(mFileMapping); 126 mFileMapping = INVALID_HANDLE_VALUE; 127 return false; 128 } 129 #endif 130 #ifdef HAVE_POSIX_FILEMAP 131 int prot, flags, adjust; 132 off_t adjOffset; 133 size_t adjLength; 134 135 void* ptr; 136 137 assert(mRefCount == 1); 138 assert(fd >= 0); 139 assert(offset >= 0); 140 assert(length > 0); 141 142 /* init on first use */ 143 if (mPageSize == -1) { 144 #if NOT_USING_KLIBC 145 mPageSize = sysconf(_SC_PAGESIZE); 146 if (mPageSize == -1) { 147 LOGE("could not get _SC_PAGESIZE\n"); 148 return false; 149 } 150 #else 151 /* this holds for Linux, Darwin, Cygwin, and doesn't pain the ARM */ 152 mPageSize = 4096; 153 #endif 154 } 155 156 adjust = offset % mPageSize; 157 try_again: 158 adjOffset = offset - adjust; 159 adjLength = length + adjust; 160 161 flags = MAP_SHARED; 162 prot = PROT_READ; 163 if (!readOnly) 164 prot |= PROT_WRITE; 165 166 ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset); 167 if (ptr == MAP_FAILED) { 168 // Cygwin does not seem to like file mapping files from an offset. 169 // So if we fail, try again with offset zero 170 if (adjOffset > 0) { 171 adjust = offset; 172 goto try_again; 173 } 174 175 LOGE("mmap(%ld,%ld) failed: %s\n", 176 (long) adjOffset, (long) adjLength, strerror(errno)); 177 return false; 178 } 179 mBasePtr = ptr; 180 #endif /* HAVE_POSIX_FILEMAP */ 181 182 mFileName = origFileName != NULL ? strdup(origFileName) : NULL; 183 mBaseLength = adjLength; 184 mDataOffset = offset; 185 mDataPtr = (char*) mBasePtr + adjust; 186 mDataLength = length; 187 188 assert(mBasePtr != NULL); 189 190 LOGV("MAP: base %p/%d data %p/%d\n", 191 mBasePtr, (int) mBaseLength, mDataPtr, (int) mDataLength); 192 193 return true; 194 } 195 196 /* 197 * Provide guidance to the system. 198 */ 199 int FileMap::advise(MapAdvice advice) 200 { 201 #if HAVE_MADVISE 202 int cc, sysAdvice; 203 204 switch (advice) { 205 case NORMAL: sysAdvice = MADV_NORMAL; break; 206 case RANDOM: sysAdvice = MADV_RANDOM; break; 207 case SEQUENTIAL: sysAdvice = MADV_SEQUENTIAL; break; 208 case WILLNEED: sysAdvice = MADV_WILLNEED; break; 209 case DONTNEED: sysAdvice = MADV_DONTNEED; break; 210 default: 211 assert(false); 212 return -1; 213 } 214 215 cc = madvise(mBasePtr, mBaseLength, sysAdvice); 216 if (cc != 0) 217 LOGW("madvise(%d) failed: %s\n", sysAdvice, strerror(errno)); 218 return cc; 219 #else 220 return -1; 221 #endif // HAVE_MADVISE 222 } 223
