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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Permission is hereby granted, free of charge, to any person
      5  * obtaining a copy of this software and associated documentation
      6  * files (the "Software"), to deal in the Software without
      7  * restriction, including without limitation the rights to use, copy,
      8  * modify, merge, publish, distribute, sublicense, and/or sell copies
      9  * of the Software, and to permit persons to whom the Software is
     10  * furnished to do so, subject to the following conditions:
     11  *
     12  * The above copyright notice and this permission notice shall be
     13  * included in all copies or substantial portions of the Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     22  * SOFTWARE.
     23  */
     24 
     25 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
     26 #error "Never include this file directly, include libavb.h instead."
     27 #endif
     28 
     29 #ifndef AVB_FOOTER_H_
     30 #define AVB_FOOTER_H_
     31 
     32 #include "avb_sysdeps.h"
     33 
     34 #ifdef __cplusplus
     35 extern "C" {
     36 #endif
     37 
     38 /* Magic for the footer. */
     39 #define AVB_FOOTER_MAGIC "AVBf"
     40 #define AVB_FOOTER_MAGIC_LEN 4
     41 
     42 /* Size of the footer. */
     43 #define AVB_FOOTER_SIZE 64
     44 
     45 /* The current footer version used - keep in sync with avbtool. */
     46 #define AVB_FOOTER_VERSION_MAJOR 1
     47 #define AVB_FOOTER_VERSION_MINOR 0
     48 
     49 /* The struct used as a footer used on partitions, used to find the
     50  * AvbVBMetaImageHeader struct. This struct is always stored at the
     51  * end of a partition.
     52  */
     53 typedef struct AvbFooter {
     54   /*   0: Four bytes equal to "AVBf" (AVB_FOOTER_MAGIC). */
     55   uint8_t magic[AVB_FOOTER_MAGIC_LEN];
     56   /*   4: The major version of the footer struct. */
     57   uint32_t version_major;
     58   /*   8: The minor version of the footer struct. */
     59   uint32_t version_minor;
     60 
     61   /*  12: The original size of the image on the partition. */
     62   uint64_t original_image_size;
     63 
     64   /*  20: The offset of the |AvbVBMetaImageHeader| struct. */
     65   uint64_t vbmeta_offset;
     66 
     67   /*  28: The size of the vbmeta block (header + auth + aux blocks). */
     68   uint64_t vbmeta_size;
     69 
     70   /*  36: Padding to ensure struct is size AVB_FOOTER_SIZE bytes. This
     71    * must be set to zeroes.
     72    */
     73   uint8_t reserved[28];
     74 } AVB_ATTR_PACKED AvbFooter;
     75 
     76 /* Copies |src| to |dest| and validates, byte-swapping fields in the
     77  * process if needed. Returns true if valid, false if invalid.
     78  */
     79 bool avb_footer_validate_and_byteswap(const AvbFooter* src, AvbFooter* dest)
     80     AVB_ATTR_WARN_UNUSED_RESULT;
     81 
     82 #ifdef __cplusplus
     83 }
     84 #endif
     85 
     86 #endif /* AVB_FOOTER_H_ */
     87