edbaed16b1
Introduce `verify-ldso-abi.sh` script and architecture-specific baseline files to the build. This new verification step is integrated into the `%check` phase of the glibc build process. It uses `gdb` to dump the internal ABI layout of critical dynamic linker data structures (`_rtld_global_ro`, `_rtld_global`, `struct link_map`, `struct pthread`) and compares them against a predefined baseline. This ensures that unintentional ABI breaks in `ld.so` are detected early, maintaining stability for internal glibc components. The script also supports generating new baselines when changes are intentional. Resolves: RHEL-72564
102 lines
2.9 KiB
Bash
102 lines
2.9 KiB
Bash
#!/bin/bash
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#
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# This script verifies the ABI of ld.so by comparing the layout of
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# critical data structures against a known baseline for a given architecture.
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#
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# This is useful to prevent unintentional ABI breaks between releases.
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#
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# Usage: ./elf/verify-ld-so-abi.sh <arch> <path-to-ld.so> [--generate-baseline]
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set -euo pipefail
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if [ "$#" -lt 2 ] || [ "$#" -gt 3 ]; then
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echo "Usage: $0 <arch> <path-to-ld.so> [--generate-baseline]"
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exit 1
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fi
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ARCH="$1"
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LDSO_PATH="$2"
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GENERATE_BASELINE=false
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if [ "${3:-}" == "--generate-baseline" ]; then
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GENERATE_BASELINE=true
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fi
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# The script is expected to be in the 'elf' directory and run from the glibc root.
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SCRIPT_DIR="$(dirname "$0")"
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BASELINE_DIR="$SCRIPT_DIR"
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BASELINE_FILE="$BASELINE_DIR/ld-so-abi-$ARCH.baseline"
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# List of structs and global variables to check in ld.so.
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# These are critical for the dynamic linker's internal ABI.
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SYMBOLS_TO_CHECK=(
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"_rtld_global_ro"
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"_rtld_global"
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"struct link_map"
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"struct pthread"
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)
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# Check for dependencies.
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if ! command -v gdb &> /dev/null; then
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echo "Error: gdb is not installed. Please install it to continue." >&2
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exit 127
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fi
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if [ ! -f "$LDSO_PATH" ]; then
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echo "Error: ld.so not found at '$LDSO_PATH'" >&2
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exit 1
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fi
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TEMP_FILE=$(mktemp)
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# Ensure the temporary file is cleaned up on script exit.
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trap 'rm -f "$TEMP_FILE"' EXIT
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echo "Generating current ABI layout for '$ARCH' from '$LDSO_PATH'..."
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for symbol in "${SYMBOLS_TO_CHECK[@]}"; do
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echo "--- $symbol ---" >> "$TEMP_FILE"
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# Use ptype/o to get the struct layout with offsets.
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# If a symbol does not exist, GDB will exit with an error, which is
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# caught by 'set -e'.
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gdb -batch -ex "ptype/o $symbol" "$LDSO_PATH" >> "$TEMP_FILE"
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done
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if [ "$GENERATE_BASELINE" = true ]; then
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echo "Generating new baseline for '$ARCH'..."
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mkdir -p "$BASELINE_DIR"
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# Atomically move the new baseline into place.
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mv "$TEMP_FILE" "$BASELINE_FILE"
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echo "Baseline created at $BASELINE_FILE"
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# The temp file has been moved, so disable the trap.
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trap - EXIT
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exit 0
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fi
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# --- Comparison Mode ---
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if [ ! -f "$BASELINE_FILE" ]; then
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echo "Error: Baseline file for architecture '$ARCH' does not exist." >&2
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echo "Path: $BASELINE_FILE" >&2
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echo >&2
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echo "To generate a new baseline, run this command with the --generate-baseline flag:" >&2
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echo "$0 $ARCH '$LDSO_PATH' --generate-baseline" >&2
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exit 77
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fi
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echo "Comparing with baseline file: $BASELINE_FILE"
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# Compare the generated layout with the official baseline.
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if ! diff -u "$BASELINE_FILE" "$TEMP_FILE"; then
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echo >&2
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echo "Error: ABI layout mismatch for '$ARCH' has been detected." >&2
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echo "The layout of structs in '$LDSO_PATH' has changed." >&2
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echo >&2
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echo "If this change is intentional, update the baseline file by running:" >&2
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echo "$0 $ARCH '$LDSO_PATH' --generate-baseline" >&2
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echo "or apply the diff output using 'patch -R'"
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exit 1
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else
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echo "OK: ABI layout for '$ARCH' is consistent with the baseline."
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exit 0
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fi
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