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 (mBasePtr && munmap(mBasePtr, mBaseLength) != 0) { 67 ALOGD("munmap(%p, %d) failed\n", mBasePtr, (int) mBaseLength); 68 } 69 #endif 70 #ifdef HAVE_WIN32_FILEMAP 71 if (mBasePtr && UnmapViewOfFile(mBasePtr) == 0) { 72 ALOGD("UnmapViewOfFile(%p) failed, error = %ld\n", mBasePtr, 73 GetLastError() ); 74 } 75 if (mFileMapping != INVALID_HANDLE_VALUE) { 76 CloseHandle(mFileMapping); 77 } 78 CloseHandle(mFileHandle); 79 #endif 80 } 81 82 83 /* 84 * Create a new mapping on an open file. 85 * 86 * Closing the file descriptor does not unmap the pages, so we don't 87 * claim ownership of the fd. 88 * 89 * Returns "false" on failure. 90 */ 91 bool FileMap::create(const char* origFileName, int fd, off64_t offset, size_t length, 92 bool readOnly) 93 { 94 #ifdef HAVE_WIN32_FILEMAP 95 int adjust; 96 off64_t adjOffset; 97 size_t adjLength; 98 99 if (mPageSize == -1) { 100 SYSTEM_INFO si; 101 102 GetSystemInfo( &si ); 103 mPageSize = si.dwAllocationGranularity; 104 } 105 106 DWORD protect = readOnly ? PAGE_READONLY : PAGE_READWRITE; 107 108 mFileHandle = (HANDLE) _get_osfhandle(fd); 109 mFileMapping = CreateFileMapping( mFileHandle, NULL, protect, 0, 0, NULL); 110 if (mFileMapping == NULL) { 111 ALOGE("CreateFileMapping(%p, %lx) failed with error %ld\n", 112 mFileHandle, protect, GetLastError() ); 113 return false; 114 } 115 116 adjust = offset % mPageSize; 117 adjOffset = offset - adjust; 118 adjLength = length + adjust; 119 120 mBasePtr = MapViewOfFile( mFileMapping, 121 readOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS, 122 0, 123 (DWORD)(adjOffset), 124 adjLength ); 125 if (mBasePtr == NULL) { 126 ALOGE("MapViewOfFile(%ld, %ld) failed with error %ld\n", 127 adjOffset, adjLength, GetLastError() ); 128 CloseHandle(mFileMapping); 129 mFileMapping = INVALID_HANDLE_VALUE; 130 return false; 131 } 132 #endif 133 #ifdef HAVE_POSIX_FILEMAP 134 int prot, flags, adjust; 135 off64_t adjOffset; 136 size_t adjLength; 137 138 void* ptr; 139 140 assert(mRefCount == 1); 141 assert(fd >= 0); 142 assert(offset >= 0); 143 assert(length > 0); 144 145 /* init on first use */ 146 if (mPageSize == -1) { 147 #if NOT_USING_KLIBC 148 mPageSize = sysconf(_SC_PAGESIZE); 149 if (mPageSize == -1) { 150 ALOGE("could not get _SC_PAGESIZE\n"); 151 return false; 152 } 153 #else 154 /* this holds for Linux, Darwin, Cygwin, and doesn't pain the ARM */ 155 mPageSize = 4096; 156 #endif 157 } 158 159 adjust = offset % mPageSize; 160 try_again: 161 adjOffset = offset - adjust; 162 adjLength = length + adjust; 163 164 flags = MAP_SHARED; 165 prot = PROT_READ; 166 if (!readOnly) 167 prot |= PROT_WRITE; 168 169 ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset); 170 if (ptr == MAP_FAILED) { 171 // Cygwin does not seem to like file mapping files from an offset. 172 // So if we fail, try again with offset zero 173 if (adjOffset > 0) { 174 adjust = offset; 175 goto try_again; 176 } 177 178 ALOGE("mmap(%ld,%ld) failed: %s\n", 179 (long) adjOffset, (long) adjLength, strerror(errno)); 180 return false; 181 } 182 mBasePtr = ptr; 183 #endif /* HAVE_POSIX_FILEMAP */ 184 185 mFileName = origFileName != NULL ? strdup(origFileName) : NULL; 186 mBaseLength = adjLength; 187 mDataOffset = offset; 188 mDataPtr = (char*) mBasePtr + adjust; 189 mDataLength = length; 190 191 assert(mBasePtr != NULL); 192 193 ALOGV("MAP: base %p/%d data %p/%d\n", 194 mBasePtr, (int) mBaseLength, mDataPtr, (int) mDataLength); 195 196 return true; 197 } 198 199 /* 200 * Provide guidance to the system. 201 */ 202 int FileMap::advise(MapAdvice advice) 203 { 204 #if HAVE_MADVISE 205 int cc, sysAdvice; 206 207 switch (advice) { 208 case NORMAL: sysAdvice = MADV_NORMAL; break; 209 case RANDOM: sysAdvice = MADV_RANDOM; break; 210 case SEQUENTIAL: sysAdvice = MADV_SEQUENTIAL; break; 211 case WILLNEED: sysAdvice = MADV_WILLNEED; break; 212 case DONTNEED: sysAdvice = MADV_DONTNEED; break; 213 default: 214 assert(false); 215 return -1; 216 } 217 218 cc = madvise(mBasePtr, mBaseLength, sysAdvice); 219 if (cc != 0) 220 ALOGW("madvise(%d) failed: %s\n", sysAdvice, strerror(errno)); 221 return cc; 222 #else 223 return -1; 224 #endif // HAVE_MADVISE 225 } 226
