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