compat/bswap.h: simplify MSVC endianness detection
[git] / t / lib-pack.sh
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
11 uint32_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 $1
20 uint32_binary () {
21         printf "$(uint32_octal "$1")"
22 }
23
24 # Print a pack header, version 2, for a pack with $1 objects
25 pack_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.
37 pack_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"
121 pack_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.
130 clear_packs () {
131         rm -f .git/objects/pack/*
132 }
133
134 test_oid_cache <<-EOF
135 packlib_7_0 sha1:01d7713666f4de822776c7622c10f1b07de280dc
136 packlib_7_0 sha256:37c8e2c15bb22b912e59b43fd51a4f7e9465ed0b5084c5a1411d991cbe630683
137
138 packlib_7_76 sha1:e68fe8129b546b101aee9510c5328e7f21ca1d18
139 packlib_7_76 sha256:5d8e6fc40f2dab00e6983a48523fe57e621f46434cb58dbd4422fba03380d886
140 EOF