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git.stella-ops.org/devops/docker/repro-builders/debian/scripts/extract-functions.sh
StellaOps Bot cec4265a40 save progress
2025-12-28 01:40:52 +02:00

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#!/bin/bash
# Extract function fingerprints from ELF binaries
# Outputs JSON array with function name, offset, size, and hashes
set -euo pipefail
DIR="${1:-.}"
extract_functions_from_binary() {
local binary="$1"
# Skip non-ELF files
file "$binary" 2>/dev/null | grep -q "ELF" || return 0
# Get function symbols with objdump
objdump -t "$binary" 2>/dev/null | \
awk '/\.text.*[0-9a-f]+.*F/ {
gsub(/\*.*\*/, "", $1)
if ($5 != "" && length($4) > 0) {
size = strtonum("0x" $4)
if (size >= 16) {
print $1, $4, $NF
}
}
}' | while read -r offset size name; do
# Skip compiler-generated symbols
case "$name" in
__*|_GLOBAL_*|.plt*|.text*|frame_dummy|register_tm_clones|deregister_tm_clones|_start|_init|_fini)
continue
;;
esac
# Convert hex size
dec_size=$((16#$size))
# Compute hash of function bytes
local hash=$(objdump -d --start-address="0x$offset" --stop-address="$((16#$offset + dec_size))" "$binary" 2>/dev/null | \
grep -E "^[[:space:]]*[0-9a-f]+:" | \
awk '{for(i=2;i<=NF;i++){if($i~/^[0-9a-f]{2}$/){printf "%s", $i}}}' | \
sha256sum | cut -d' ' -f1)
[ -n "$hash" ] || hash="unknown"
printf '{"name":"%s","offset":"0x%s","size":%d,"hash":"%s"}\n' \
"$name" "$offset" "$dec_size" "$hash"
done
}
# Output JSON array
echo "["
first=true
find "$DIR" -type f \( -executable -o -name "*.so" -o -name "*.so.*" \) 2>/dev/null | while read -r binary; do
file "$binary" 2>/dev/null | grep -q "ELF" || continue
extract_functions_from_binary "$binary" | while read -r json; do
[ -z "$json" ] && continue
if [ "$first" = "true" ]; then
first=false
echo "$json"
else
echo ",$json"
fi
done
done
echo "]"