forked from OSchip/llvm-project
325 lines
12 KiB
C++
325 lines
12 KiB
C++
//===-- DataBufferMemoryMap.cpp ---------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// C Includes
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#include <fcntl.h>
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#include <sys/stat.h>
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#ifdef _WIN32
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#include "lldb/Host/windows/windows.h"
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#else
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#include <sys/mman.h>
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#endif
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// C++ Includes
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#include <cerrno>
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#include <climits>
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// Other libraries and framework includes
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#include "llvm/Support/MathExtras.h"
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// Project includes
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#include "lldb/Core/DataBufferMemoryMap.h"
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#include "lldb/Core/Error.h"
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#include "lldb/Host/File.h"
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#include "lldb/Host/FileSpec.h"
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#include "lldb/Host/HostInfo.h"
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#include "lldb/Core/Log.h"
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using namespace lldb;
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using namespace lldb_private;
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//----------------------------------------------------------------------
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// Default Constructor
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//----------------------------------------------------------------------
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DataBufferMemoryMap::DataBufferMemoryMap() :
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m_mmap_addr(nullptr),
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m_mmap_size(0),
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m_data(nullptr),
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m_size(0)
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{
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}
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//----------------------------------------------------------------------
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// Virtual destructor since this class inherits from a pure virtual
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// base class.
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//----------------------------------------------------------------------
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DataBufferMemoryMap::~DataBufferMemoryMap()
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{
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Clear();
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}
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//----------------------------------------------------------------------
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// Return a pointer to the bytes owned by this object, or nullptr if
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// the object contains no bytes.
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//----------------------------------------------------------------------
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uint8_t *
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DataBufferMemoryMap::GetBytes()
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{
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return m_data;
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}
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//----------------------------------------------------------------------
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// Return a const pointer to the bytes owned by this object, or nullptr
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// if the object contains no bytes.
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//----------------------------------------------------------------------
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const uint8_t *
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DataBufferMemoryMap::GetBytes() const
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{
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return m_data;
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}
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//----------------------------------------------------------------------
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// Return the number of bytes this object currently contains.
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//----------------------------------------------------------------------
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uint64_t
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DataBufferMemoryMap::GetByteSize() const
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{
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return m_size;
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}
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//----------------------------------------------------------------------
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// Reverts this object to an empty state by unmapping any memory
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// that is currently owned.
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//----------------------------------------------------------------------
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void
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DataBufferMemoryMap::Clear()
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{
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if (m_mmap_addr != nullptr)
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{
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Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_MMAP));
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if (log)
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log->Printf("DataBufferMemoryMap::Clear() m_mmap_addr = %p, m_mmap_size = %" PRIu64 "", (void *)m_mmap_addr,
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(uint64_t)m_mmap_size);
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#ifdef _WIN32
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UnmapViewOfFile(m_mmap_addr);
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#else
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::munmap((void *)m_mmap_addr, m_mmap_size);
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#endif
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m_mmap_addr = nullptr;
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m_mmap_size = 0;
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m_data = nullptr;
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m_size = 0;
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}
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}
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//----------------------------------------------------------------------
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// Memory map "length" bytes from "file" starting "offset"
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// bytes into the file. If "length" is set to SIZE_MAX, then
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// map as many bytes as possible.
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//
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// Returns the number of bytes mapped starting from the requested
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// offset.
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//----------------------------------------------------------------------
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size_t
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DataBufferMemoryMap::MemoryMapFromFileSpec (const FileSpec* filespec,
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lldb::offset_t offset,
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size_t length,
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bool writeable)
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{
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if (filespec != nullptr)
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{
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Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_MMAP));
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if (log)
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{
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log->Printf("DataBufferMemoryMap::MemoryMapFromFileSpec(file=\"%s\", offset=0x%" PRIx64 ", length=0x%" PRIx64 ", writeable=%i",
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filespec->GetPath().c_str(),
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offset,
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(uint64_t)length,
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writeable);
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}
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char path[PATH_MAX];
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if (filespec->GetPath(path, sizeof(path)))
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{
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uint32_t options = File::eOpenOptionRead;
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if (writeable)
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options |= File::eOpenOptionWrite;
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File file;
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Error error (file.Open(path, options));
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if (error.Success())
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{
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const bool fd_is_file = true;
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return MemoryMapFromFileDescriptor (file.GetDescriptor(), offset, length, writeable, fd_is_file);
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}
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}
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}
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// We should only get here if there was an error
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Clear();
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return 0;
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}
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#ifdef _WIN32
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static size_t win32memmapalignment = 0;
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void LoadWin32MemMapAlignment ()
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{
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SYSTEM_INFO data;
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GetSystemInfo(&data);
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win32memmapalignment = data.dwAllocationGranularity;
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}
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#endif
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//----------------------------------------------------------------------
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// The file descriptor FD is assumed to already be opened as read only
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// and the STAT structure is assumed to a valid pointer and already
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// containing valid data from a call to stat().
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//
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// Memory map FILE_LENGTH bytes in FILE starting FILE_OFFSET bytes into
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// the file. If FILE_LENGTH is set to SIZE_MAX, then map as many bytes
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// as possible.
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//
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// RETURNS
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// Number of bytes mapped starting from the requested offset.
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//----------------------------------------------------------------------
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size_t
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DataBufferMemoryMap::MemoryMapFromFileDescriptor (int fd,
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lldb::offset_t offset,
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size_t length,
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bool writeable,
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bool fd_is_file)
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{
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Clear();
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if (fd >= 0)
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{
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Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_MMAP|LIBLLDB_LOG_VERBOSE));
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if (log)
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{
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log->Printf("DataBufferMemoryMap::MemoryMapFromFileDescriptor(fd=%i, offset=0x%" PRIx64 ", length=0x%" PRIx64 ", writeable=%i, fd_is_file=%i)",
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fd,
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offset,
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(uint64_t)length,
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writeable,
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fd_is_file);
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}
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#ifdef _WIN32
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HANDLE handle = (HANDLE)_get_osfhandle(fd);
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DWORD file_size_low, file_size_high;
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file_size_low = GetFileSize(handle, &file_size_high);
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const lldb::offset_t file_size = llvm::Make_64(file_size_high, file_size_low);
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const lldb::offset_t max_bytes_available = file_size - offset;
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const size_t max_bytes_mappable = (size_t)std::min<lldb::offset_t>(SIZE_MAX, max_bytes_available);
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if (length == SIZE_MAX || length > max_bytes_mappable)
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{
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// Cap the length if too much data was requested
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length = max_bytes_mappable;
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}
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if (length > 0)
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{
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HANDLE fileMapping = CreateFileMapping(handle, nullptr, writeable ? PAGE_READWRITE : PAGE_READONLY, file_size_high, file_size_low, nullptr);
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if (fileMapping != nullptr)
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{
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if (win32memmapalignment == 0) LoadWin32MemMapAlignment();
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lldb::offset_t realoffset = offset;
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lldb::offset_t delta = 0;
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if (realoffset % win32memmapalignment != 0) {
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realoffset = realoffset / win32memmapalignment * win32memmapalignment;
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delta = offset - realoffset;
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}
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LPVOID data = MapViewOfFile(fileMapping, writeable ? FILE_MAP_WRITE : FILE_MAP_READ, 0, realoffset, length + delta);
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m_mmap_addr = (uint8_t *)data;
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if (!data) {
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Error error;
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error.SetErrorToErrno ();
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} else {
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m_data = m_mmap_addr + delta;
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m_size = length;
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}
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CloseHandle(fileMapping);
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}
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}
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#else
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struct stat stat;
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if (::fstat(fd, &stat) == 0)
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{
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if (S_ISREG(stat.st_mode) &&
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(stat.st_size > static_cast<off_t>(offset)))
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{
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const size_t max_bytes_available = stat.st_size - offset;
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if (length == SIZE_MAX)
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{
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length = max_bytes_available;
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}
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else if (length > max_bytes_available)
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{
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// Cap the length if too much data was requested
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length = max_bytes_available;
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}
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if (length > 0)
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{
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int prot = PROT_READ;
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if (writeable)
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prot |= PROT_WRITE;
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int flags = MAP_PRIVATE;
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if (fd_is_file)
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flags |= MAP_FILE;
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m_mmap_addr = (uint8_t *)::mmap(nullptr, length, prot, flags, fd, offset);
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Error error;
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if (m_mmap_addr == (void*)-1)
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{
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error.SetErrorToErrno ();
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if (error.GetError() == EINVAL)
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{
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// We may still have a shot at memory mapping if we align things correctly
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size_t page_offset = offset % HostInfo::GetPageSize();
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if (page_offset != 0)
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{
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m_mmap_addr = (uint8_t *)::mmap(nullptr, length + page_offset, prot, flags, fd, offset - page_offset);
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if (m_mmap_addr == (void*)-1)
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{
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// Failed to map file
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m_mmap_addr = nullptr;
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}
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else if (m_mmap_addr != nullptr)
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{
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// We recovered and were able to memory map
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// after we aligned things to page boundaries
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// Save the actual mmap'ed size
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m_mmap_size = length + page_offset;
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// Our data is at an offset into the mapped data
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m_data = m_mmap_addr + page_offset;
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// Our pretend size is the size that was requested
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m_size = length;
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}
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}
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}
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if (error.GetError() == ENOMEM)
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{
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error.SetErrorStringWithFormat("could not allocate %" PRId64 " bytes of memory to mmap in file", (uint64_t) length);
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}
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}
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else
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{
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// We were able to map the requested data in one chunk
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// where our mmap and actual data are the same.
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m_mmap_size = length;
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m_data = m_mmap_addr;
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m_size = length;
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}
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if (log)
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{
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log->Printf(
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"DataBufferMemoryMap::MemoryMapFromFileSpec() m_mmap_addr = %p, m_mmap_size = %" PRIu64
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", error = %s",
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(void *)m_mmap_addr, (uint64_t)m_mmap_size, error.AsCString());
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}
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}
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}
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}
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#endif
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}
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return GetByteSize ();
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}
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