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      1 /*
      2  * Copyright (C) 2008 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 #define LOG_TAG "MemoryHeapBase"
     18 
     19 #include <stdlib.h>
     20 #include <stdint.h>
     21 #include <unistd.h>
     22 #include <fcntl.h>
     23 #include <errno.h>
     24 #include <sys/types.h>
     25 #include <sys/stat.h>
     26 #include <sys/ioctl.h>
     27 
     28 #include <cutils/log.h>
     29 #include <cutils/ashmem.h>
     30 #include <cutils/atomic.h>
     31 
     32 #include <binder/MemoryHeapBase.h>
     33 
     34 namespace android {
     35 
     36 // ---------------------------------------------------------------------------
     37 
     38 MemoryHeapBase::MemoryHeapBase()
     39     : mFD(-1), mSize(0), mBase(MAP_FAILED),
     40       mDevice(NULL), mNeedUnmap(false), mOffset(0)
     41 {
     42 }
     43 
     44 MemoryHeapBase::MemoryHeapBase(size_t size, uint32_t flags, char const * name)
     45     : mFD(-1), mSize(0), mBase(MAP_FAILED), mFlags(flags),
     46       mDevice(0), mNeedUnmap(false), mOffset(0)
     47 {
     48     const size_t pagesize = getpagesize();
     49     size = ((size + pagesize-1) & ~(pagesize-1));
     50     int fd = ashmem_create_region(name == NULL ? "MemoryHeapBase" : name, size);
     51     ALOGE_IF(fd<0, "error creating ashmem region: %s", strerror(errno));
     52     if (fd >= 0) {
     53         if (mapfd(fd, size) == NO_ERROR) {
     54             if (flags & READ_ONLY) {
     55                 ashmem_set_prot_region(fd, PROT_READ);
     56             }
     57         }
     58     }
     59 }
     60 
     61 MemoryHeapBase::MemoryHeapBase(const char* device, size_t size, uint32_t flags)
     62     : mFD(-1), mSize(0), mBase(MAP_FAILED), mFlags(flags),
     63       mDevice(0), mNeedUnmap(false), mOffset(0)
     64 {
     65     int open_flags = O_RDWR;
     66     if (flags & NO_CACHING)
     67         open_flags |= O_SYNC;
     68 
     69     int fd = open(device, open_flags);
     70     ALOGE_IF(fd<0, "error opening %s: %s", device, strerror(errno));
     71     if (fd >= 0) {
     72         const size_t pagesize = getpagesize();
     73         size = ((size + pagesize-1) & ~(pagesize-1));
     74         if (mapfd(fd, size) == NO_ERROR) {
     75             mDevice = device;
     76         }
     77     }
     78 }
     79 
     80 MemoryHeapBase::MemoryHeapBase(int fd, size_t size, uint32_t flags, uint32_t offset)
     81     : mFD(-1), mSize(0), mBase(MAP_FAILED), mFlags(flags),
     82       mDevice(0), mNeedUnmap(false), mOffset(0)
     83 {
     84     const size_t pagesize = getpagesize();
     85     size = ((size + pagesize-1) & ~(pagesize-1));
     86     mapfd(dup(fd), size, offset);
     87 }
     88 
     89 status_t MemoryHeapBase::init(int fd, void *base, int size, int flags, const char* device)
     90 {
     91     if (mFD != -1) {
     92         return INVALID_OPERATION;
     93     }
     94     mFD = fd;
     95     mBase = base;
     96     mSize = size;
     97     mFlags = flags;
     98     mDevice = device;
     99     return NO_ERROR;
    100 }
    101 
    102 status_t MemoryHeapBase::mapfd(int fd, size_t size, uint32_t offset)
    103 {
    104     if (size == 0) {
    105         // try to figure out the size automatically
    106         struct stat sb;
    107         if (fstat(fd, &sb) == 0)
    108             size = sb.st_size;
    109         // if it didn't work, let mmap() fail.
    110     }
    111 
    112     if ((mFlags & DONT_MAP_LOCALLY) == 0) {
    113         void* base = (uint8_t*)mmap(0, size,
    114                 PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
    115         if (base == MAP_FAILED) {
    116             ALOGE("mmap(fd=%d, size=%u) failed (%s)",
    117                     fd, uint32_t(size), strerror(errno));
    118             close(fd);
    119             return -errno;
    120         }
    121         //ALOGD("mmap(fd=%d, base=%p, size=%lu)", fd, base, size);
    122         mBase = base;
    123         mNeedUnmap = true;
    124     } else  {
    125         mBase = 0; // not MAP_FAILED
    126         mNeedUnmap = false;
    127     }
    128     mFD = fd;
    129     mSize = size;
    130     mOffset = offset;
    131     return NO_ERROR;
    132 }
    133 
    134 MemoryHeapBase::~MemoryHeapBase()
    135 {
    136     dispose();
    137 }
    138 
    139 void MemoryHeapBase::dispose()
    140 {
    141     int fd = android_atomic_or(-1, &mFD);
    142     if (fd >= 0) {
    143         if (mNeedUnmap) {
    144             //ALOGD("munmap(fd=%d, base=%p, size=%lu)", fd, mBase, mSize);
    145             munmap(mBase, mSize);
    146         }
    147         mBase = 0;
    148         mSize = 0;
    149         close(fd);
    150     }
    151 }
    152 
    153 int MemoryHeapBase::getHeapID() const {
    154     return mFD;
    155 }
    156 
    157 void* MemoryHeapBase::getBase() const {
    158     return mBase;
    159 }
    160 
    161 size_t MemoryHeapBase::getSize() const {
    162     return mSize;
    163 }
    164 
    165 uint32_t MemoryHeapBase::getFlags() const {
    166     return mFlags;
    167 }
    168 
    169 const char* MemoryHeapBase::getDevice() const {
    170     return mDevice;
    171 }
    172 
    173 uint32_t MemoryHeapBase::getOffset() const {
    174     return mOffset;
    175 }
    176 
    177 // ---------------------------------------------------------------------------
    178 }; // namespace android
    179