freshlybakedca.ke
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1# Support routines for hand-crafting weird or malicious packs.
2#
3# You can make a complete pack like:
4#
5# pack_header 2 >foo.pack &&
6# pack_obj e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 >>foo.pack &&
7# pack_obj e68fe8129b546b101aee9510c5328e7f21ca1d18 >>foo.pack &&
8# pack_trailer foo.pack
9
10# Print the big-endian 4-byte octal representation of $1
11uint32_octal () {
12 n=$1
13 printf '\\%o' $(($n / 16777216)); n=$((n % 16777216))
14 printf '\\%o' $(($n / 65536)); n=$((n % 65536))
15 printf '\\%o' $(($n / 256)); n=$((n % 256))
16 printf '\\%o' $(($n ));
17}
18
19# Print the big-endian 4-byte binary representation of $1
20uint32_binary () {
21 printf "$(uint32_octal "$1")"
22}
23
24# Print a pack header, version 2, for a pack with $1 objects
25pack_header () {
26 printf 'PACK' &&
27 printf '\0\0\0\2' &&
28 uint32_binary "$1"
29}
30
31# Print the pack data for object $1, as a delta against object $2 (or as a full
32# object if $2 is missing or empty). The output is suitable for including
33# directly in the packfile, and represents the entirety of the object entry.
34# Doing this on the fly (especially picking your deltas) is quite tricky, so we
35# have hardcoded some well-known objects. See the case statements below for the
36# complete list.
37pack_obj () {
38 case "$1" in
39 # empty blob
40 $EMPTY_BLOB)
41 case "$2" in
42 '')
43 printf '\060\170\234\003\0\0\0\0\1'
44 return
45 ;;
46 esac
47 ;;
48
49 # blob containing "\7\76"
50 $(test_oid packlib_7_76))
51 case "$2" in
52 '')
53 printf '\062\170\234\143\267\3\0\0\116\0\106'
54 return
55 ;;
56 01d7713666f4de822776c7622c10f1b07de280dc)
57 printf '\165\1\327\161\66\146\364\336\202\47\166' &&
58 printf '\307\142\54\20\361\260\175\342\200\334\170' &&
59 printf '\234\143\142\142\142\267\003\0\0\151\0\114'
60 return
61 ;;
62 37c8e2c15bb22b912e59b43fd51a4f7e9465ed0b5084c5a1411d991cbe630683)
63 printf '\165\67\310\342\301\133\262\53\221\56\131' &&
64 printf '\264\77\325\32\117\176\224\145\355\13\120' &&
65 printf '\204\305\241\101\35\231\34\276\143\6\203\170' &&
66 printf '\234\143\142\142\142\267\003\0\0\151\0\114'
67 return
68 ;;
69 esac
70 ;;
71
72 # blob containing "\7\0"
73 $(test_oid packlib_7_0))
74 case "$2" in
75 '')
76 printf '\062\170\234\143\147\0\0\0\20\0\10'
77 return
78 ;;
79 e68fe8129b546b101aee9510c5328e7f21ca1d18)
80 printf '\165\346\217\350\22\233\124\153\20\32\356' &&
81 printf '\225\20\305\62\216\177\41\312\35\30\170\234' &&
82 printf '\143\142\142\142\147\0\0\0\53\0\16'
83 return
84 ;;
85 5d8e6fc40f2dab00e6983a48523fe57e621f46434cb58dbd4422fba03380d886)
86 printf '\165\135\216\157\304\17\55\253\0\346\230\72' &&
87 printf '\110\122\77\345\176\142\37\106\103\114\265' &&
88 printf '\215\275\104\42\373\240\63\200\330\206\170\234' &&
89 printf '\143\142\142\142\147\0\0\0\53\0\16'
90 return
91 ;;
92 esac
93 ;;
94 # blob containing "\3\326"
95 471819e8c52bf11513f100b2810a8aa0622d5cd3d1c913758a071dd4b3bad8fe)
96 case "$2" in
97 '')
98 printf '\062\170\234\143\276\006\000\000\336\000\332'
99 return
100 ;;
101 esac
102 esac
103
104 # If it's not a delta, we can convince pack-objects to generate a pack
105 # with just our entry, and then strip off the header (12 bytes) and
106 # trailer (20 bytes).
107 if test -z "$2"
108 then
109 echo "$1" | git pack-objects --stdout >pack_obj.tmp &&
110 size=$(wc -c <pack_obj.tmp) &&
111 dd if=pack_obj.tmp bs=1 count=$((size - $(test_oid rawsz) - 12)) skip=12 &&
112 rm -f pack_obj.tmp
113 return
114 fi
115
116 echo >&2 "BUG: don't know how to print $1${2:+ (from $2)}"
117 return 1
118}
119
120# Compute and append pack trailer to "$1"
121pack_trailer () {
122 test-tool $(test_oid algo) -b <"$1" >trailer.tmp &&
123 cat trailer.tmp >>"$1" &&
124 rm -f trailer.tmp
125}
126
127# Remove any existing packs to make sure that
128# whatever we index next will be the pack that we
129# actually use.
130clear_packs () {
131 rm -f .git/objects/pack/*
132}
133
134test_oid_cache <<-EOF
135packlib_7_0 sha1:01d7713666f4de822776c7622c10f1b07de280dc
136packlib_7_0 sha256:37c8e2c15bb22b912e59b43fd51a4f7e9465ed0b5084c5a1411d991cbe630683
137
138packlib_7_76 sha1:e68fe8129b546b101aee9510c5328e7f21ca1d18
139packlib_7_76 sha256:5d8e6fc40f2dab00e6983a48523fe57e621f46434cb58dbd4422fba03380d886
140EOF