1 /* 2 * Copyright (C) 2018 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 #pragma once 17 18 #include <stdint.h> 19 20 #include <memory> 21 #include <string> 22 23 #include "common/libs/fs/shared_fd.h" 24 25 namespace cvd { 26 27 // Unpacks the boot image and extracts kernel, ramdisk and kernel arguments 28 class BootImageUnpacker { 29 public: 30 // Reads header section of boot image at path and returns a BootImageUnpacker 31 // preloaded with all the metadata. 32 static std::unique_ptr<BootImageUnpacker> FromImages( 33 const std::string& boot_image_path, 34 const std::string& vendor_boot_image_path); 35 36 ~BootImageUnpacker() = default; 37 38 std::string kernel_cmdline() const; 39 HasKernelImage()40 bool HasKernelImage() const { return kernel_image_size_ > 0; } HasRamdiskImage()41 bool HasRamdiskImage() const { return ramdisk_image_size_ > 0; } HasVendorRamdiskImage()42 bool HasVendorRamdiskImage() const { return vendor_ramdisk_image_size_ > 0; } 43 44 bool Unpack(const std::string& ramdisk_image_path, 45 const std::string& vendor_ramdisk_image_path, 46 const std::string& kernel_image_path); 47 48 private: BootImageUnpacker(SharedFD boot_image,const std::string & cmdline,uint32_t kernel_image_size,uint32_t kernel_image_offset,uint32_t ramdisk_image_size,uint32_t ramdisk_image_offset,SharedFD vendor_boot_image,uint32_t vendor_ramdisk_image_size,uint32_t vendor_ramdisk_image_offset)49 BootImageUnpacker(SharedFD boot_image, const std::string& cmdline, 50 uint32_t kernel_image_size, uint32_t kernel_image_offset, 51 uint32_t ramdisk_image_size, uint32_t ramdisk_image_offset, 52 SharedFD vendor_boot_image, 53 uint32_t vendor_ramdisk_image_size, 54 uint32_t vendor_ramdisk_image_offset) 55 : boot_image_(boot_image), 56 vendor_boot_image_(vendor_boot_image), 57 kernel_cmdline_(cmdline), 58 kernel_image_size_(kernel_image_size), 59 kernel_image_offset_(kernel_image_offset), 60 ramdisk_image_size_(ramdisk_image_size), 61 ramdisk_image_offset_(ramdisk_image_offset), 62 vendor_ramdisk_image_size_(vendor_ramdisk_image_size), 63 vendor_ramdisk_image_offset_(vendor_ramdisk_image_offset) {} 64 65 // Mutable because we only read from the fd, but do not modify its contents 66 mutable SharedFD boot_image_; 67 mutable SharedFD vendor_boot_image_; 68 std::string kernel_cmdline_; 69 // When buidling the boot image a particular page size is assumed, which may 70 // not match the actual page size of the system. 71 uint32_t kernel_image_size_; 72 uint32_t kernel_image_offset_; 73 uint32_t ramdisk_image_size_; 74 uint32_t ramdisk_image_offset_; 75 uint32_t vendor_ramdisk_image_size_; 76 uint32_t vendor_ramdisk_image_offset_; 77 78 // Extracts the kernel image to the given path 79 bool ExtractKernelImage(const std::string& path) const; 80 // Extracts the ramdisk image to the given path. It may return false if the 81 // boot image does not contain a ramdisk, which is the case when having system 82 // as root. 83 bool ExtractRamdiskImage(const std::string& path) const; 84 // Extracts the vendor ramdisk image to the given path 85 bool ExtractVendorRamdiskImage(const std::string& path) const; 86 }; 87 88 } // namespace cvd 89