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/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//
// Shared file mapping class.
//
#define LOG_TAG "filemap"
#include <utils/FileMap.h>
#include <utils/Log.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_POSIX_FILEMAP
#include <sys/mman.h>
#endif
#include <string.h>
#include <memory.h>
#include <errno.h>
#include <assert.h>
using namespace android;
/*static*/ long FileMap::mPageSize = -1;
/*
* Constructor. Create an empty object.
*/
FileMap::FileMap(void)
: mRefCount(1), mFileName(NULL), mBasePtr(NULL), mBaseLength(0),
mDataPtr(NULL), mDataLength(0)
{
}
/*
* Destructor.
*/
FileMap::~FileMap(void)
{
assert(mRefCount == 0);
//printf("+++ removing FileMap %p %u\n", mDataPtr, mDataLength);
mRefCount = -100; // help catch double-free
if (mFileName != NULL) {
free(mFileName);
}
#ifdef HAVE_POSIX_FILEMAP
if (munmap(mBasePtr, mBaseLength) != 0) {
LOGD("munmap(%p, %d) failed\n", mBasePtr, (int) mBaseLength);
}
#endif
#ifdef HAVE_WIN32_FILEMAP
if ( UnmapViewOfFile(mBasePtr) == 0) {
LOGD("UnmapViewOfFile(%p) failed, error = %ld\n", mBasePtr,
GetLastError() );
}
CloseHandle(mFileMapping);
CloseHandle(mFileHandle);
#endif
}
/*
* Create a new mapping on an open file.
*
* Closing the file descriptor does not unmap the pages, so we don't
* claim ownership of the fd.
*
* Returns "false" on failure.
*/
bool FileMap::create(const char* origFileName, int fd, off_t offset, size_t length, bool readOnly)
{
#ifdef HAVE_WIN32_FILEMAP
int adjust;
off_t adjOffset;
size_t adjLength;
if (mPageSize == -1) {
SYSTEM_INFO si;
GetSystemInfo( &si );
mPageSize = si.dwAllocationGranularity;
}
DWORD protect = readOnly ? PAGE_READONLY : PAGE_READWRITE;
mFileHandle = (HANDLE) _get_osfhandle(fd);
mFileMapping = CreateFileMapping( mFileHandle, NULL, protect, 0, 0, NULL);
if (mFileMapping == NULL) {
LOGE("CreateFileMapping(%p, %lx) failed with error %ld\n",
mFileHandle, protect, GetLastError() );
return false;
}
adjust = offset % mPageSize;
adjOffset = offset - adjust;
adjLength = length + adjust;
mBasePtr = MapViewOfFile( mFileMapping,
readOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS,
0,
(DWORD)(adjOffset),
adjLength );
if (mBasePtr == NULL) {
LOGE("MapViewOfFile(%ld, %ld) failed with error %ld\n",
adjOffset, adjLength, GetLastError() );
CloseHandle(mFileMapping);
mFileMapping = INVALID_HANDLE_VALUE;
return false;
}
#endif
#ifdef HAVE_POSIX_FILEMAP
int prot, flags, adjust;
off_t adjOffset;
size_t adjLength;
void* ptr;
assert(mRefCount == 1);
assert(fd >= 0);
assert(offset >= 0);
assert(length > 0);
/* init on first use */
if (mPageSize == -1) {
#if NOT_USING_KLIBC
mPageSize = sysconf(_SC_PAGESIZE);
if (mPageSize == -1) {
LOGE("could not get _SC_PAGESIZE\n");
return false;
}
#else
/* this holds for Linux, Darwin, Cygwin, and doesn't pain the ARM */
mPageSize = 4096;
#endif
}
adjust = offset % mPageSize;
try_again:
adjOffset = offset - adjust;
adjLength = length + adjust;
flags = MAP_SHARED;
prot = PROT_READ;
if (!readOnly)
prot |= PROT_WRITE;
ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset);
if (ptr == MAP_FAILED) {
// Cygwin does not seem to like file mapping files from an offset.
// So if we fail, try again with offset zero
if (adjOffset > 0) {
adjust = offset;
goto try_again;
}
LOGE("mmap(%ld,%ld) failed: %s\n",
(long) adjOffset, (long) adjLength, strerror(errno));
return false;
}
mBasePtr = ptr;
#endif /* HAVE_POSIX_FILEMAP */
mFileName = origFileName != NULL ? strdup(origFileName) : NULL;
mBaseLength = adjLength;
mDataOffset = offset;
mDataPtr = (char*) mBasePtr + adjust;
mDataLength = length;
assert(mBasePtr != NULL);
LOGV("MAP: base %p/%d data %p/%d\n",
mBasePtr, (int) mBaseLength, mDataPtr, (int) mDataLength);
return true;
}
/*
* Provide guidance to the system.
*/
int FileMap::advise(MapAdvice advice)
{
#if HAVE_MADVISE
int cc, sysAdvice;
switch (advice) {
case NORMAL: sysAdvice = MADV_NORMAL; break;
case RANDOM: sysAdvice = MADV_RANDOM; break;
case SEQUENTIAL: sysAdvice = MADV_SEQUENTIAL; break;
case WILLNEED: sysAdvice = MADV_WILLNEED; break;
case DONTNEED: sysAdvice = MADV_DONTNEED; break;
default:
assert(false);
return -1;
}
cc = madvise(mBasePtr, mBaseLength, sysAdvice);
if (cc != 0)
LOGW("madvise(%d) failed: %s\n", sysAdvice, strerror(errno));
return cc;
#else
return -1;
#endif // HAVE_MADVISE
}
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