1#!/bin/bash
2
3if [ $# -ne 3 ]; then
4  echo "Usage: $0 <vbmeta.img> <system.img> <VbmetaBootParams.textproto>"
5  exit 0
6fi
7
8# Example Output from 'avbtool calculate_vbmeta_digest --image $OUT/vbmeta.img':
9# 3254db8a232946c712b5c6f8c1a80b31f2a200bab98553d86f5915d06bfd5436
10#
11# Example Output from 'avbtool info_image --image $OUT/vbmeta.img':
12#
13# Minimum libavb version:   1.0
14# Header Block:             256 bytes
15# Authentication Block:     576 bytes
16# Auxiliary Block:          1600 bytes
17# Algorithm:                SHA256_RSA4096
18# Rollback Index:           0
19# Flags:                    0
20# Release String:           'avbtool 1.1.0'
21# Descriptors:
22# ...
23#
24#
25
26set -e
27
28function die {
29  echo $1 >&2
30  exit 1
31}
32
33# Incrementing major version causes emulator binaries that do not support the
34# version to ignore this file.  This can be useful if there is a change
35# not supported by older emulator binaries.
36readonly MAJOR_VERSION=2
37
38readonly VBMETAIMG=$1
39readonly SYSIMG=$2
40readonly TARGET=$3
41
42# Extract the digest
43readonly VBMETA_DIGEST=$(${AVBTOOL:-avbtool} calculate_vbmeta_digest --image $VBMETAIMG)
44
45
46readonly INFO_OUTPUT=$(${AVBTOOL:-avbtool} info_image --image $VBMETAIMG | grep "^Algorithm:")
47
48# Extract the algorithm
49readonly ALG_OUTPUT=$(echo $INFO_OUTPUT | grep "Algorithm:")
50readonly ALG_SPLIT=($(echo $ALG_OUTPUT | tr ' ' '\n'))
51readonly ORG_ALGORITHM=${ALG_SPLIT[1]}
52
53if [[ $ORG_ALGORITHM == "SHA256_RSA4096" ]]; then
54VBMETA_HASH_ALG=sha256
55else
56die "Don't know anything about $ORG_ALGORITHM"
57fi
58
59
60# extract the size
61
62function get_bytes {
63    MY_OUTPUT=$(${AVBTOOL:-avbtool} info_image --image $1 | grep "$2" )
64    MY_SPLIT=($(echo $MY_OUTPUT | tr ' ' '\n'))
65    MY_BYTES=${MY_SPLIT[2]}
66    echo $MY_BYTES
67}
68
69HEADER_SIZE=$(get_bytes $VBMETAIMG "Header Block:")
70AUTHEN_SIZE=$(get_bytes $VBMETAIMG "Authentication Block:")
71AUX_SIZE=$(get_bytes $VBMETAIMG "Auxiliary Block:")
72SYSMETA_SIZE=$(get_bytes $SYSIMG "VBMeta size:")
73
74VBMETA_SIZE=$(expr $HEADER_SIZE + $AUTHEN_SIZE + $AUX_SIZE + $SYSMETA_SIZE)
75
76
77HEADER_COMMENT="# androidboot.vbmeta.size=$VBMETA_SIZE androidboot.vbmeta.hash_alg=$VBMETA_HASH_ALG androidboot.vbmeta.digest=$VBMETA_DIGEST"
78
79echo $HEADER_COMMENT > $TARGET
80echo "major_version: $MAJOR_VERSION" >> $TARGET
81#echo "param: \"androidboot.slot_suffix=_a\"" >> $TARGET
82echo "param: \"androidboot.vbmeta.size=$VBMETA_SIZE\"" >> $TARGET
83echo "param: \"androidboot.vbmeta.hash_alg=$VBMETA_HASH_ALG\"" >> $TARGET
84echo "param: \"androidboot.vbmeta.digest=$VBMETA_DIGEST\"" >> $TARGET
85