15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "chrome/app/image_pre_reader_win.h" 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <windows.h> 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <algorithm> 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <limits> 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <vector> 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/logging.h" 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/scoped_ptr.h" 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/thread_restrictions.h" 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/win/pe_image.h" 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/win/scoped_handle.h" 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/win/windows_version.h" 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace { 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The minimum buffer size to allocate when reading the PE file headers. 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The PE file headers usually fit into a single 1KB page, and a PE file must 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// at least contain the initial page with the headers. That said, as long as 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// we expect at least sizeof(IMAGE_DOS_HEADER) bytes, we're ok. 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)const size_t kMinHeaderBufferSize = 0x400; 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A handy symbolic constant. 29d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles)const size_t kOneHundredPercent = 100; 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void StaticAssertions() { 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) COMPILE_ASSERT(kMinHeaderBufferSize >= sizeof(IMAGE_DOS_HEADER), 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) min_header_buffer_size_at_least_as_big_as_the_dos_header); 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This struct provides a deallocation functor for use with scoped_ptr<T> 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// allocated with ::VirtualAlloc(). 385d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)struct VirtualFreeDeleter { 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void operator() (void* ptr) { 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ::VirtualFree(ptr, 0, MEM_RELEASE); 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A wrapper for the Win32 ::SetFilePointer() function with some error checking. 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool SetFilePointer(HANDLE file_handle, size_t position) { 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return position <= static_cast<size_t>(std::numeric_limits<LONG>::max()) && 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ::SetFilePointer(file_handle, 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<LONG>(position), 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL, 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FILE_BEGIN) != INVALID_SET_FILE_POINTER; 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A helper function to read the next |bytes_to_read| bytes from the file 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// given by |file_handle| into |buffer|. 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ReadNextBytes(HANDLE file_handle, void* buffer, size_t bytes_to_read) { 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(file_handle != INVALID_HANDLE_VALUE); 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(buffer != NULL); 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(bytes_to_read > 0); 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DWORD bytes_read = 0; 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return bytes_to_read <= std::numeric_limits<DWORD>::max() && 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ::ReadFile(file_handle, 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) buffer, 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<DWORD>(bytes_to_read), 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) &bytes_read, 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL) && 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bytes_read == bytes_to_read; 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A helper function to extend the |current_buffer| of bytes such that it 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// contains |desired_length| bytes read from the file given by |file_handle|. 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// It is assumed that |file_handle| has been used to sequentially populate 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// |current_buffer| thus far and is already positioned at the appropriate 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// read location. 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ReadMissingBytes(HANDLE file_handle, 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::vector<uint8>* current_buffer, 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t desired_length) { 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(file_handle != INVALID_HANDLE_VALUE); 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(current_buffer != NULL); 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t current_length = current_buffer->size(); 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (current_length >= desired_length) 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t bytes_to_read = desired_length - current_length; 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) current_buffer->resize(desired_length); 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ReadNextBytes(file_handle, 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) &(current_buffer->at(current_length)), 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bytes_to_read); 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Return a |percentage| of the number of initialized bytes in the given 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// |section|. 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This returns a percentage of the lesser of the size of the raw data in 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// the section and the virtual size of the section. 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Note that sections can have their tails implicitly initialized to zero 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// (i.e., their virtual size is larger than the raw size) and that raw data 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// is padded to the PE page size if the entire section is initialized (i.e., 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// their raw data size will be larger than the virtual size). 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Any data after the initialized portion of the section will be soft-faulted 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// in (very quickly) as needed, so we don't need to include it in the returned 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// length. 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)size_t GetPercentageOfSectionLength(const IMAGE_SECTION_HEADER* section, 108d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) size_t percentage) { 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(section != NULL); 110d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) DCHECK_GT(percentage, 0u); 1115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK_LE(percentage, kOneHundredPercent); 1125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t initialized_length = std::min(section->SizeOfRawData, 1145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) section->Misc.VirtualSize); 1155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (initialized_length == 0) 1175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return 0; 1185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t length = (initialized_length * percentage) / kOneHundredPercent; 1205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return std::max<size_t>(length, 1); 1225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Helper function to read through a |percentage| of the given |section| 1255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// of the file denoted by |file_handle|. The |temp_buffer| is (re)used as 1265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// a transient storage area as the section is read in chunks of 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// |temp_buffer_size| bytes. 1285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ReadThroughSection(HANDLE file_handle, 1295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const IMAGE_SECTION_HEADER* section, 130d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) size_t percentage, 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void* temp_buffer, 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t temp_buffer_size) { 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(file_handle != INVALID_HANDLE_VALUE); 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(section != NULL); 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK_LE(percentage, kOneHundredPercent); 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(temp_buffer != NULL); 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(temp_buffer_size > 0); 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t bytes_to_read = GetPercentageOfSectionLength(section, percentage); 1405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (bytes_to_read == 0) 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!SetFilePointer(file_handle, section->PointerToRawData)) 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Read all chunks except the last one. 1475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (bytes_to_read > temp_buffer_size) { 1485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!ReadNextBytes(file_handle, temp_buffer, temp_buffer_size)) 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bytes_to_read -= temp_buffer_size; 1515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Read the last (possibly partial) chunk and return. 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(bytes_to_read > 0); 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(bytes_to_read <= temp_buffer_size); 1565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ReadNextBytes(file_handle, temp_buffer, bytes_to_read); 1575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A helper function to touch all pages in the range 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// [base_addr, base_addr + length). 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void TouchPagesInRange(void* base_addr, size_t length) { 1625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(base_addr != NULL); 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(length > 0); 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Get the system info so we know the page size. Also, make sure we use a 1665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // non-zero value for the page size; GetSystemInfo() is hookable/patchable, 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // and you never know what shenanigans someone could get up to. 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SYSTEM_INFO system_info = {}; 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) GetSystemInfo(&system_info); 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (system_info.dwPageSize == 0) 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) system_info.dwPageSize = 4096; 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // We don't want to read outside the byte range (which could trigger an 1745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // access violation), so let's figure out the exact locations of the first 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // and final bytes we want to read. 1765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) volatile uint8* touch_ptr = reinterpret_cast<uint8*>(base_addr); 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) volatile uint8* final_touch_ptr = touch_ptr + length - 1; 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Read the memory in the range [touch_ptr, final_touch_ptr] with a stride 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // of the system page size, to ensure that it's been paged in. 1815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) uint8 dummy; 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (touch_ptr < final_touch_ptr) { 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dummy = *touch_ptr; 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) touch_ptr += system_info.dwPageSize; 1855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dummy = *final_touch_ptr; 1875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace 1905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ImagePreReader::PartialPreReadImageOnDisk(const wchar_t* file_path, 192d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) size_t percentage, 1935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t max_chunk_size) { 1945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // TODO(rogerm): change this to have the number of bytes pre-read per 1955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // section be driven by a static table within the PE file (defaulting to 1965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // full read if it's not there?) that's initialized by the optimization 1975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // toolchain. 1985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(file_path != NULL); 1995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (percentage == 0) 2015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 2025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (percentage > kOneHundredPercent) 2045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) percentage = kOneHundredPercent; 2055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Validate/setup max_chunk_size, imposing a 1MB minimum on the chunk size. 2075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const size_t kMinChunkSize = 1024 * 1024; 2085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) max_chunk_size = std::max(max_chunk_size, kMinChunkSize); 2095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Open the file. 2115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::win::ScopedHandle file( 2125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CreateFile(file_path, 2135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) GENERIC_READ, 2145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 2155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL, 2165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) OPEN_EXISTING, 2175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FILE_FLAG_SEQUENTIAL_SCAN, 2185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL)); 2195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!file.IsValid()) 2215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Allocate a resizable buffer for the headers. We initially reserve as much 2245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // space as we typically see as the header size for chrome.dll and other 2255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // PE images. 2265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::vector<uint8> headers; 2275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) headers.reserve(kMinHeaderBufferSize); 2285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Read, hopefully, all of the headers. 2305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!ReadMissingBytes(file, &headers, kMinHeaderBufferSize)) 2315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The DOS header starts at offset 0 and allows us to get the offset of the 2345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // NT headers. Let's ensure we've read enough to capture the NT headers. 2355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t nt_headers_start = 2365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) reinterpret_cast<IMAGE_DOS_HEADER*>(&headers[0])->e_lfanew; 2375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t nt_headers_end = nt_headers_start + sizeof(IMAGE_NT_HEADERS); 2385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!ReadMissingBytes(file, &headers, nt_headers_end)) 2395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Now that we've got the NT headers we can get the total header size, 2425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // including all of the section headers. Let's ensure we've read enough 2435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // to capture all of the header data. 2445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t size_of_headers = reinterpret_cast<IMAGE_NT_HEADERS*>( 2455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) &headers[nt_headers_start])->OptionalHeader.SizeOfHeaders; 2465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!ReadMissingBytes(file, &headers, size_of_headers)) 2475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Now we have all of the headers. This is enough to let us use the PEImage 2505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // wrapper to query the structure of the image. 2515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::win::PEImage pe_image(reinterpret_cast<HMODULE>(&headers[0])); 2525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK(pe_image.VerifyMagic()); 2535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Allocate a buffer to hold the pre-read bytes. 2555d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) scoped_ptr<uint8, VirtualFreeDeleter> buffer( 2565d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) static_cast<uint8*>( 2575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ::VirtualAlloc(NULL, max_chunk_size, MEM_COMMIT, PAGE_READWRITE))); 2585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (buffer.get() == NULL) 2595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Iterate over each section, reading in a percentage of each. 2625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const IMAGE_SECTION_HEADER* section = NULL; 2635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (UINT i = 0; (section = pe_image.GetSectionHeader(i)) != NULL; ++i) { 2645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK_LE(reinterpret_cast<const uint8*>(section + 1), 2655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) &headers[0] + headers.size()); 2665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!ReadThroughSection( 2675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) file, section, percentage, buffer.get(), max_chunk_size)) 2685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // We're done. 2725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 2735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 2745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ImagePreReader::PartialPreReadImageInMemory(const wchar_t* file_path, 276d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) size_t percentage) { 2775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // TODO(rogerm): change this to have the number of bytes pre-read per 2785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // section be driven by a static table within the PE file (defaulting to 2795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // full read if it's not there?) that's initialized by the optimization 2805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // toolchain. 2815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(file_path != NULL); 2825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (percentage == 0) 2845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 2855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (percentage > kOneHundredPercent) 2875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) percentage = kOneHundredPercent; 2885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) HMODULE dll_module = ::LoadLibraryExW( 2905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) file_path, 2915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL, 2925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LOAD_WITH_ALTERED_SEARCH_PATH | DONT_RESOLVE_DLL_REFERENCES); 2935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!dll_module) 2955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::win::PEImage pe_image(dll_module); 2985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK(pe_image.VerifyMagic()); 2995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Iterate over each section, stepping through a percentage of each to page 3015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // it in off the disk. 3025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const IMAGE_SECTION_HEADER* section = NULL; 3035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (UINT i = 0; (section = pe_image.GetSectionHeader(i)) != NULL; ++i) { 3045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Get the extent we want to touch. 3055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t length = GetPercentageOfSectionLength(section, percentage); 3065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (length == 0) 3075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) continue; 3085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) uint8* start = 3095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint8*>(pe_image.RVAToAddr(section->VirtualAddress)); 3105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Verify that the extent we're going to touch falls inside the section 3125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // we expect it to (and by implication, inside the pe_image). 3135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK_EQ(section, 3145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) pe_image.GetImageSectionFromAddr(start)); 3155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK_EQ(section, 3165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) pe_image.GetImageSectionFromAddr(start + length - 1)); 3175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Page in the section range. 3195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) TouchPagesInRange(start, length); 3205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 3215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FreeLibrary(dll_module); 3235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 3255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 3265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ImagePreReader::PreReadImage(const wchar_t* file_path, 3285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t size_to_read, 3295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t step_size) { 3305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::ThreadRestrictions::AssertIOAllowed(); 3315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (base::win::GetVersion() > base::win::VERSION_XP) { 3325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Vista+ branch. On these OSes, the forced reads through the DLL actually 3335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // slows warm starts. The solution is to sequentially read file contents 3345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // with an optional cap on total amount to read. 3355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::win::ScopedHandle file( 3365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CreateFile(file_path, 3375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) GENERIC_READ, 3385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 3395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL, 3405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) OPEN_EXISTING, 3415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FILE_FLAG_SEQUENTIAL_SCAN, 3425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL)); 3435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!file.IsValid()) 3455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 3465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Default to 1MB sequential reads. 3485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const DWORD actual_step_size = std::max(static_cast<DWORD>(step_size), 3495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<DWORD>(1024*1024)); 3505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LPVOID buffer = ::VirtualAlloc(NULL, 3515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) actual_step_size, 3525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) MEM_COMMIT, 3535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) PAGE_READWRITE); 3545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (buffer == NULL) 3565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 3575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DWORD len; 3595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t total_read = 0; 3605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (::ReadFile(file, buffer, actual_step_size, &len, NULL) && 3615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len > 0 && 3625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (size_to_read ? total_read < size_to_read : true)) { 3635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) total_read += static_cast<size_t>(len); 3645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 3655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ::VirtualFree(buffer, 0, MEM_RELEASE); 3665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 3675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // WinXP branch. Here, reading the DLL from disk doesn't do 3685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // what we want so instead we pull the pages into memory by loading 3695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the DLL and touching pages at a stride. We use the system's page 3705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // size as the stride, ignoring the passed in step_size, to make sure 3715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // each page in the range is touched. 3725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) HMODULE dll_module = ::LoadLibraryExW( 3735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) file_path, 3745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NULL, 3755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LOAD_WITH_ALTERED_SEARCH_PATH | DONT_RESOLVE_DLL_REFERENCES); 3765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!dll_module) 3785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 3795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::win::PEImage pe_image(dll_module); 3815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CHECK(pe_image.VerifyMagic()); 3825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // We don't want to read past the end of the module (which could trigger 3845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // an access violation), so make sure to check the image size. 3855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) PIMAGE_NT_HEADERS nt_headers = pe_image.GetNTHeaders(); 3865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t dll_module_length = std::min( 3875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_to_read ? size_to_read : ~0, 3885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<size_t>(nt_headers->OptionalHeader.SizeOfImage)); 3895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Page in then release the module. 3915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) TouchPagesInRange(dll_module, dll_module_length); 3925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FreeLibrary(dll_module); 3935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 3945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 3965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 3975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 3985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool ImagePreReader::PartialPreReadImage(const wchar_t* file_path, 399d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles) size_t percentage, 4005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t max_chunk_size) { 4015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::ThreadRestrictions::AssertIOAllowed(); 4025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 4035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (percentage >= kOneHundredPercent) { 4045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If we're reading the whole image, we don't need to parse headers and 4055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // navigate sections, the basic PreReadImage() can be used to just step 4065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // blindly through the entire file / address-space. 4075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return PreReadImage(file_path, 0, max_chunk_size); 4085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 4095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 4105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (base::win::GetVersion() > base::win::VERSION_XP) { 4115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Vista+ branch. On these OSes, we warm up the Image by reading its 4125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // file off the disk. 4135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return PartialPreReadImageOnDisk(file_path, percentage, max_chunk_size); 4145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 4155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 4165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // WinXP branch. For XP, reading the image from disk doesn't do what we want 4175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // so instead we pull the pages into memory by loading the DLL and touching 4185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // initialized pages at a stride. 4195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return PartialPreReadImageInMemory(file_path, percentage); 4205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 421