/*
* Parses autopilot heading message (page 1)
*/
bool tCanKingProtocol::AutopilotHeading( const quint8* pData, quint16& actualHeading )
{
if( PageNumber( pData ) == 1 )
{
actualHeading = qFromBigEndian< quint16 >( pData+4 );
return true;
}
return false;
}
PageNumber *getFrameContents (BM_BufferPool *const bm){
PageNumber (*arr)[bm->numPages];
arr=calloc(bm->numPages,sizeof(PageNumber));
for (int i =g_queue->queueSize-1;i>=0;i--)
{
(*arr)[i]=bufferInfo[i]->PageNum;
}
return *arr;
}
bool
MappableSeekableZStream::ensure(const void *addr)
{
DEBUG_LOG("ensure @%p", addr);
const void *addrPage = PageAlignedPtr(addr);
/* Find the mapping corresponding to the given page */
std::vector<LazyMap>::iterator map;
for (map = lazyMaps.begin(); map < lazyMaps.end(); ++map) {
if (map->Contains(addrPage))
break;
}
if (map == lazyMaps.end())
return false;
/* Find corresponding chunk */
off_t mapOffset = map->offsetOf(addrPage);
off_t chunk = mapOffset / zStream.GetChunkSize();
/* In the typical case, we just need to decompress the chunk entirely. But
* when the current mapping ends in the middle of the chunk, we want to
* stop at the end of the corresponding page.
* However, if another mapping needs the last part of the chunk, we still
* need to continue. As mappings are ordered by offset and length, we don't
* need to scan the entire list of mappings.
* It is safe to run through lazyMaps here because the linker is never
* going to call mmap (which adds lazyMaps) while this function is
* called. */
size_t length = zStream.GetChunkSize(chunk);
off_t chunkStart = chunk * zStream.GetChunkSize();
off_t chunkEnd = chunkStart + length;
std::vector<LazyMap>::iterator it;
for (it = map; it < lazyMaps.end(); ++it) {
if (chunkEnd <= it->endOffset())
break;
}
if ((it == lazyMaps.end()) || (chunkEnd > it->endOffset())) {
/* The mapping "it" points at now is past the interesting one */
--it;
length = it->endOffset() - chunkStart;
}
length = PageAlignedSize(length);
/* The following lock can be re-acquired by the thread holding it.
* If this happens, it means the following code is interrupted somehow by
* some signal, and ends up retriggering a chunk decompression for the
* same MappableSeekableZStream.
* If the chunk to decompress is different the second time, then everything
* is safe as the only common data touched below is chunkAvailNum, and it is
* atomically updated (leaving out any chance of an interruption while it is
* updated affecting the result). If the chunk to decompress is the same, the
* worst thing that can happen is chunkAvailNum being incremented one too
* many times, which doesn't affect functionality. The chances of it
* happening being pretty slim, and the effect being harmless, we can just
* ignore the issue. Other than that, we'd just be wasting time decompressing
* the same chunk twice. */
AutoLock lock(&mutex);
/* The very first page is mapped and accessed separately of the rest, and
* as such, only the first page of the first chunk is decompressed this way.
* When we fault in the remaining pages of that chunk, we want to decompress
* the complete chunk again. Short of doing that, we would end up with
* no data between PageSize() and chunkSize, which would effectively corrupt
* symbol resolution in the underlying library. */
if (chunkAvail[chunk] < PageNumber(length)) {
if (!zStream.DecompressChunk(*buffer + chunkStart, chunk, length))
return false;
#if defined(ANDROID) && defined(__arm__)
if (map->prot & PROT_EXEC) {
/* We just extracted data that may be executed in the future.
* We thus need to ensure Instruction and Data cache coherency. */
DEBUG_LOG("cacheflush(%p, %p)", *buffer + chunkStart, *buffer + (chunkStart + length));
cacheflush(reinterpret_cast<uintptr_t>(*buffer + chunkStart),
reinterpret_cast<uintptr_t>(*buffer + (chunkStart + length)), 0);
}
#endif
/* Only count if we haven't already decompressed parts of the chunk */
if (chunkAvail[chunk] == 0)
chunkAvailNum++;
chunkAvail[chunk] = PageNumber(length);
}
/* Flip the chunk mapping protection to the recorded flags. We could
* also flip the protection for other mappings of the same chunk,
* but it's easier to skip that and let further segfaults call
* ensure again. */
const void *chunkAddr = reinterpret_cast<const void *>
(reinterpret_cast<uintptr_t>(addrPage)
- mapOffset % zStream.GetChunkSize());
const void *chunkEndAddr = reinterpret_cast<const void *>
(reinterpret_cast<uintptr_t>(chunkAddr) + length);
const void *start = std::max(map->addr, chunkAddr);
const void *end = std::min(map->end(), chunkEndAddr);
length = reinterpret_cast<uintptr_t>(end)
- reinterpret_cast<uintptr_t>(start);
DEBUG_LOG("mprotect @%p, 0x%" PRIxSize ", 0x%x", start, length, map->prot);
if (mprotect(const_cast<void *>(start), length, map->prot) == 0)
return true;
LOG("mprotect failed");
return false;
}
