141 lines
4.0 KiB
Bash
141 lines
4.0 KiB
Bash
# Support routines for hand-crafting weird or malicious packs.
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#
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# You can make a complete pack like:
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#
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# pack_header 2 >foo.pack &&
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# pack_obj e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 >>foo.pack &&
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# pack_obj e68fe8129b546b101aee9510c5328e7f21ca1d18 >>foo.pack &&
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# pack_trailer foo.pack
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# Print the big-endian 4-byte octal representation of $1
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uint32_octal () {
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n=$1
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printf '\\%o' $(($n / 16777216)); n=$((n % 16777216))
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printf '\\%o' $(($n / 65536)); n=$((n % 65536))
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printf '\\%o' $(($n / 256)); n=$((n % 256))
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printf '\\%o' $(($n ));
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}
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# Print the big-endian 4-byte binary representation of $1
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uint32_binary () {
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printf "$(uint32_octal "$1")"
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}
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# Print a pack header, version 2, for a pack with $1 objects
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pack_header () {
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printf 'PACK' &&
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printf '\0\0\0\2' &&
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uint32_binary "$1"
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}
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# Print the pack data for object $1, as a delta against object $2 (or as a full
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# object if $2 is missing or empty). The output is suitable for including
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# directly in the packfile, and represents the entirety of the object entry.
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# Doing this on the fly (especially picking your deltas) is quite tricky, so we
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# have hardcoded some well-known objects. See the case statements below for the
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# complete list.
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pack_obj () {
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case "$1" in
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# empty blob
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$EMPTY_BLOB)
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case "$2" in
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'')
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printf '\060\170\234\003\0\0\0\0\1'
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return
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;;
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esac
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;;
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# blob containing "\7\76"
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$(test_oid packlib_7_76))
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case "$2" in
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'')
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printf '\062\170\234\143\267\3\0\0\116\0\106'
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return
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;;
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01d7713666f4de822776c7622c10f1b07de280dc)
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printf '\165\1\327\161\66\146\364\336\202\47\166' &&
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printf '\307\142\54\20\361\260\175\342\200\334\170' &&
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printf '\234\143\142\142\142\267\003\0\0\151\0\114'
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return
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;;
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37c8e2c15bb22b912e59b43fd51a4f7e9465ed0b5084c5a1411d991cbe630683)
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printf '\165\67\310\342\301\133\262\53\221\56\131' &&
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printf '\264\77\325\32\117\176\224\145\355\13\120' &&
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printf '\204\305\241\101\35\231\34\276\143\6\203\170' &&
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printf '\234\143\142\142\142\267\003\0\0\151\0\114'
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return
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;;
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esac
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;;
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# blob containing "\7\0"
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$(test_oid packlib_7_0))
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case "$2" in
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'')
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printf '\062\170\234\143\147\0\0\0\20\0\10'
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return
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;;
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e68fe8129b546b101aee9510c5328e7f21ca1d18)
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printf '\165\346\217\350\22\233\124\153\20\32\356' &&
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printf '\225\20\305\62\216\177\41\312\35\30\170\234' &&
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printf '\143\142\142\142\147\0\0\0\53\0\16'
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return
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;;
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5d8e6fc40f2dab00e6983a48523fe57e621f46434cb58dbd4422fba03380d886)
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printf '\165\135\216\157\304\17\55\253\0\346\230\72' &&
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printf '\110\122\77\345\176\142\37\106\103\114\265' &&
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printf '\215\275\104\42\373\240\63\200\330\206\170\234' &&
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printf '\143\142\142\142\147\0\0\0\53\0\16'
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return
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;;
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esac
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;;
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# blob containing "\3\326"
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471819e8c52bf11513f100b2810a8aa0622d5cd3d1c913758a071dd4b3bad8fe)
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case "$2" in
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'')
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printf '\062\170\234\143\276\006\000\000\336\000\332'
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return
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;;
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esac
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esac
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# If it's not a delta, we can convince pack-objects to generate a pack
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# with just our entry, and then strip off the header (12 bytes) and
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# trailer (20 bytes).
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if test -z "$2"
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then
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echo "$1" | git pack-objects --stdout >pack_obj.tmp &&
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size=$(wc -c <pack_obj.tmp) &&
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dd if=pack_obj.tmp bs=1 count=$((size - $(test_oid rawsz) - 12)) skip=12 &&
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rm -f pack_obj.tmp
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return
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fi
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echo >&2 "BUG: don't know how to print $1${2:+ (from $2)}"
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return 1
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}
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# Compute and append pack trailer to "$1"
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pack_trailer () {
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test-tool $(test_oid algo) -b <"$1" >trailer.tmp &&
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cat trailer.tmp >>"$1" &&
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rm -f trailer.tmp
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}
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# Remove any existing packs to make sure that
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# whatever we index next will be the pack that we
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# actually use.
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clear_packs () {
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rm -f .git/objects/pack/*
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}
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test_oid_cache <<-EOF
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packlib_7_0 sha1:01d7713666f4de822776c7622c10f1b07de280dc
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packlib_7_0 sha256:37c8e2c15bb22b912e59b43fd51a4f7e9465ed0b5084c5a1411d991cbe630683
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packlib_7_76 sha1:e68fe8129b546b101aee9510c5328e7f21ca1d18
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packlib_7_76 sha256:5d8e6fc40f2dab00e6983a48523fe57e621f46434cb58dbd4422fba03380d886
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EOF
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