#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-only
# Script to check commits for UAPI backwards compatibility
set -o errexit
set -o pipefail
print_usage() {
name=$(basename "$0")
cat << EOF
$name - check for UAPI header stability across Git commits
By default, the script will check to make sure the latest commit (or current
dirty changes) did not introduce ABI changes when compared to HEAD^1. You can
check against additional commit ranges with the -b and -p options.
The script will not check UAPI headers for architectures other than the one
defined in ARCH.
Usage: $name [-b BASE_REF] [-p PAST_REF] [-j N] [-l ERROR_LOG] [-i] [-q] [-v]
Options:
-b BASE_REF Base git reference to use for comparison. If unspecified or empty,
will use any dirty changes in tree to UAPI files. If there are no
dirty changes, HEAD will be used.
-p PAST_REF Compare BASE_REF to PAST_REF (e.g. -p v6.1). If unspecified or empty,
will use BASE_REF^1. Must be an ancestor of BASE_REF. Only headers
that exist on PAST_REF will be checked for compatibility.
-j JOBS Number of checks to run in parallel (default: number of CPU cores).
-l ERROR_LOG Write error log to file (default: no error log is generated).
-i Ignore ambiguous changes that may or may not break UAPI compatibility.
-q Quiet operation.
-v Verbose operation (print more information about each header being checked).
Environmental args:
ABIDIFF Custom path to abidiff binary
CC C compiler (default is "gcc")
ARCH Target architecture for the UAPI check (default is host arch)
Exit codes:
$SUCCESS) Success
$FAIL_ABI) ABI difference detected
$FAIL_PREREQ) Prerequisite not met
EOF
}
readonly SUCCESS=0
readonly FAIL_ABI=1
readonly FAIL_PREREQ=2
# Print to stderr
eprintf() {
# shellcheck disable=SC2059
printf "$@" >&2
}
# Expand an array with a specific character (similar to Python string.join())
join() {
local IFS="$1"
shift
printf "%s" "$*"
}
# Create abidiff suppressions
gen_suppressions() {
# Common enum variant names which we don't want to worry about
# being shifted when new variants are added.
local -a enum_regex=(
".*_AFTER_LAST$"
".*_CNT$"
".*_COUNT$"
".*_END$"
".*_LAST$"
".*_MASK$"
".*_MAX$"
".*_MAX_BIT$"
".*_MAX_BPF_ATTACH_TYPE$"
".*_MAX_ID$"
".*_MAX_SHIFT$"
".*_NBITS$"
".*_NETDEV_NUMHOOKS$"
".*_NFT_META_IIFTYPE$"
".*_NL80211_ATTR$"
".*_NLDEV_NUM_OPS$"
".*_NUM$"
".*_NUM_ELEMS$"
".*_NUM_IRQS$"
".*_SIZE$"
".*_TLSMAX$"
"^MAX_.*"
"^NUM_.*"
)
# Common padding field names which can be expanded into
# without worrying about users.
local -a padding_regex=(
".*end$"
".*pad$"
".*pad[0-9]?$"
".*pad_[0-9]?$"
".*padding$"
".*padding[0-9]?$"
".*padding_[0-9]?$"
".*res$"
".*resv$"
".*resv[0-9]?$"
".*resv_[0-9]?$"
".*reserved$"
".*reserved[0-9]?$"
".*reserved_[0-9]?$"
".*rsvd[0-9]?$"
".*unused$"
)
cat << EOF
[suppress_type]
type_kind = enum
changed_enumerators_regexp = $(join , "${enum_regex[@]}")
EOF
for p in "${padding_regex[@]}"; do
cat << EOF
[suppress_type]
type_kind = struct
has_data_member_inserted_at = offset_of_first_data_member_regexp(${p})
EOF
done
if [ "$IGNORE_AMBIGUOUS_CHANGES" = "true" ]; then
cat << EOF
[suppress_type]
type_kind = struct
has_data_member_inserted_at = end
has_size_change = yes
EOF
fi
}
# Check if git tree is dirty
tree_is_dirty() {
! git diff --quiet
}
# Get list of files installed in $ref
get_file_list() {
local -r ref="$1"
local -r tree="$(get_header_tree "$ref")"
# Print all installed headers, filtering out ones that can't be compiled
find "$tree" -type f -name '*.h' -printf '%P\n' | grep -v -f "$INCOMPAT_LIST"
}
# Add to the list of incompatible headers
add_to_incompat_list() {
local -r ref="$1"
# Start with the usr/include/Makefile to get a list of the headers
# that don't compile using this method.
if [ ! -f usr/include/Makefile ]; then
eprintf "error - no usr/include/Makefile present at %s\n" "$ref"
eprintf "Note: usr/include/Makefile was added in the v5.3 kernel release\n"
exit "$FAIL_PREREQ"
fi
{
# shellcheck disable=SC2016
printf 'all: ; @echo $(no-header-test)\n'
cat usr/include/Makefile
} | SRCARCH="$ARCH" make --always-make -f - | tr " " "\n" \
| grep -v "asm-generic" >> "$INCOMPAT_LIST"
# The makefile also skips all asm-generic files, but prints "asm-generic/%"
# which won't work for our grep match. Instead, print something grep will match.
printf "asm-generic/.*\.h\n" >> "$INCOMPAT_LIST"
}
# Compile the simple test app
do_compile() {
local -r inc_dir="$1"
local -r header="$2"
local -r out="$3"
printf "int main(void) { return 0; }\n" | \
"$CC" -c \
-o "$out" \
-x c \
-O0 \
-std=c90 \
-fno-eliminate-unused-debug-types \
-g \
"-I${inc_dir}" \
-include "$header" \
-
}
# Run make headers_install
run_make_headers_install() {
local -r ref="$1"
local -r install_dir="$(get_header_tree "$ref")"
make -j "$MAX_THREADS" ARCH="$ARCH" INSTALL_HDR_PATH="$install_dir" \
headers_install > /dev/null
}
# Install headers for both git refs
install_headers() {
local -r base_ref="$1"
local -r past_ref="$2"
for ref in "$base_ref" "$past_ref"; do
printf "Installing user-facing UAPI headers from %s... " "${ref:-dirty tree}"
if [ -n "$ref" ]; then
git archive --format=tar --prefix="${ref}-archive/" "$ref" \
| (cd "$TMP_DIR" && tar xf -)
(
cd "${TMP_DIR}/${ref}-archive"
run_make_headers_install "$ref"
add_to_incompat_list "$ref" "$INCOMPAT_LIST"
)
else
run_make_headers_install "$ref"
add_to_incompat_list "$ref" "$INCOMPAT_LIST"
fi
printf "OK\n"
done
sort -u -o "$INCOMPAT_LIST" "$INCOMPAT_LIST"
sed -i -e '/^$/d' "$INCOMPAT_LIST"
}
# Print the path to the headers_install tree for a given ref
get_header_tree() {
local -r ref="$1"
printf "%s" "${TMP_DIR}/${ref}/usr"
}
# Check file list for UAPI compatibility
check_uapi_files() {
local -r base_ref="$1"
local -r past_ref="$2"
local -r abi_error_log="$3"
local passed=0;
local failed=0;
local -a threads=()
set -o errexit
printf "Checking changes to UAPI headers between %s and %s...\n" "$past_ref" "${base_ref:-dirty tree}"
# Loop over all UAPI headers that were installed by $past_ref (if they only exist on $base_ref,
# there's no way they're broken and no way to compare anyway)
while read -r file; do
if [ "${#threads[@]}" -ge "$MAX_THREADS" ]; then
if wait "${threads[0]}"; then
passed=$((passed + 1))
else
failed=$((failed + 1))
fi
threads=("${threads[@]:1}")
fi
check_individual_file "$base_ref" "$past_ref" "$file" &
threads+=("$!")
done < <(get_file_list "$past_ref")
for t in "${threads[@]}"; do
if wait "$t"; then
passed=$((passed + 1))
else
failed=$((failed + 1))
fi
done
if [ -n "$abi_error_log" ]; then
printf 'Generated by "%s %s" from git ref %s\n\n' \
"$0" "$*" "$(git rev-parse HEAD)" > "$abi_error_log"
fi
while read -r error_file; do
{
cat "$error_file"
printf "\n\n"
} | tee -a "${abi_error_log:-/dev/null}" >&2
done < <(find "$TMP_DIR" -type f -name '*.error' | sort)
total="$((passed + failed))"
if [ "$failed" -gt 0 ]; then
eprintf "error - %d/%d UAPI headers compatible with %s appear _not_ to be backwards compatible\n" \
"$failed" "$total" "$ARCH"
if [ -n "$abi_error_log" ]; then
eprintf "Failure summary saved to %s\n" "$abi_error_log"
fi
else
printf "All %d UAPI headers compatible with %s appear to be backwards compatible\n" \
"$total" "$ARCH"
fi
return "$failed"
}
# Check an individual file for UAPI compatibility
check_individual_file() {
local -r base_ref="$1"
local -r past_ref="$2"
local -r file="$3"
local -r base_header="$(get_header_tree "$base_ref")/${file}"
local -r past_header="$(get_header_tree "$past_ref")/${file}"
if [ ! -f "$base_header" ]; then
mkdir -p "$(dirname "$base_header")"
printf "==== UAPI header %s was removed between %s and %s ====" \
"$file" "$past_ref" "$base_ref" \
> "${base_header}.error"
return 1
fi
compare_abi "$file" "$base_header" "$past_header" "$base_ref" "$past_ref"
}
# Perform the A/B compilation and compare output ABI
compare_abi() {
local -r file="$1"
local -r base_header="$2"
local -r past_header="$3"
local -r base_ref="$4"
local -r past_ref="$5"
local -r log="${TMP_DIR}/log/${file}.log"
local -r error_log="${TMP_DIR}/log/${file}.error"
mkdir -p "$(dirname "$log")"
if ! do_compile "$(get_header_tree "$base_ref")/include" "$base_header" "${base_header}.bin" 2> "$log"; then
{
warn_str=$(printf "==== Could not compile version of UAPI header %s at %s ====\n" \
"$file" "$base_ref")
printf "%s\n" "$warn_str"
cat "$log"
printf -- "=%.0s" $(seq 0 ${#warn_str})
} > "$error_log"
return 1
fi
if ! do_compile "$(get_header_tree "$past_ref")/include" "$past_header" "${past_header}.bin" 2> "$log"; then
{
warn_str=$(printf "==== Could not compile version of UAPI header %s at %s ====\n" \
"$file" "$past_ref")
printf "%s\n" "$warn_str"
cat "$log"
printf -- "=%.0s" $(seq 0 ${#warn_str})
} > "$error_log"
return 1
fi
local ret=0
"$ABIDIFF" --non-reachable-types \
--suppressions "$SUPPRESSIONS" \
"${past_header}.bin" "${base_header}.bin" > "$log" || ret="$?"
if [ "$ret" -eq 0 ]; then
if [ "$VERBOSE" = "true" ]; then
printf "No ABI differences detected in %s from %s -> %s\n" \
"$file" "$past_ref" "$base_ref"
fi
else
# Bits in abidiff's return code can be used to determine the type of error
if [ $((ret & 0x2)) -gt 0 ]; then
eprintf "error - abidiff did not run properly\n"
exit 1
fi
if [ "$IGNORE_AMBIGUOUS_CHANGES" = "true" ] && [ "$ret" -eq 4 ]; then
return 0
fi
# If the only changes were additions (not modifications to existing APIs), then
# there's no problem. Ignore these diffs.
if grep "Unreachable types summary" "$log" | grep -q "0 removed" &&
grep "Unreachable types summary" "$log" | grep -q "0 changed"; then
return 0
fi
{
warn_str=$(printf "==== ABI differences detected in %s from %s -> %s ====" \
"$file" "$past_ref" "$base_ref")
printf "%s\n" "$warn_str"
sed -e '/summary:/d' -e '/changed type/d' -e '/^$/d' -e 's/^/ /g' "$log"
printf -- "=%.0s" $(seq 0 ${#warn_str})
if cmp "$past_header" "$base_header" > /dev/null 2>&1; then
printf "\n%s did not change between %s and %s...\n" "$file" "$past_ref" "${base_ref:-dirty tree}"
printf "It's possible a change to one of the headers it includes caused this error:\n"
grep '^#include' "$base_header"
printf "\n"
fi
} > "$error_log"
return 1
fi
}
# Check that a minimum software version number is satisfied
min_version_is_satisfied() {
local -r min_version="$1"
local -r version_installed="$2"
printf "%s\n%s\n" "$min_version" "$version_installed" \
| sort -Vc > /dev/null 2>&1
}
# Make sure we have the tools we need and the arguments make sense
check_deps() {
ABIDIFF="${ABIDIFF:-abidiff}"
CC="${CC:-gcc}"
ARCH="${ARCH:-$(uname -m)}"
if [ "$ARCH" = "x86_64" ]; then
ARCH="x86"
fi
local -r abidiff_min_version="2.4"
local -r libdw_min_version_if_clang="0.171"
if ! command -v "$ABIDIFF" > /dev/null 2>&1; then
eprintf "error - abidiff not found!\n"
eprintf "Please install abigail-tools version %s or greater\n" "$abidiff_min_version"
eprintf "See: https://sourceware.org/libabigail/manual/libabigail-overview.html\n"
return 1
fi
local -r abidiff_version="$("$ABIDIFF" --version | cut -d ' ' -f 2)"
if ! min_version_is_satisfied "$abidiff_min_version" "$abidiff_version"; then
eprintf "error - abidiff version too old: %s\n" "$abidiff_version"
eprintf "Please install abigail-tools version %s or greater\n" "$abidiff_min_version"
eprintf "See: https://sourceware.org/libabigail/manual/libabigail-overview.html\n"
return 1
fi
if ! command -v "$CC" > /dev/null 2>&1; then
eprintf 'error - %s not found\n' "$CC"
return 1
fi
if "$CC" --version | grep -q clang; then
local -r libdw_version="$(ldconfig -v 2>/dev/null | grep -v SKIPPED | grep -m 1 -o 'libdw-[0-9]\+.[0-9]\+' | cut -c 7-)"
if ! min_version_is_satisfied "$libdw_min_version_if_clang" "$libdw_version"; then
eprintf "error - libdw version too old for use with clang: %s\n" "$libdw_version"
eprintf "Please install libdw from elfutils version %s or greater\n" "$libdw_min_version_if_clang"
eprintf "See: https://sourceware.org/elfutils/\n"
return 1
fi
fi
if [ ! -d "arch/${ARCH}" ]; then
eprintf 'error - ARCH "%s" is not a subdirectory under arch/\n' "$ARCH"
eprintf "Please set ARCH to one of:\n%s\n" "$(find arch -maxdepth 1 -mindepth 1 -type d -printf '%f ' | fmt)"
return 1
fi
if ! git rev-parse --is-inside-work-tree > /dev/null 2>&1; then
eprintf "error - this script requires the kernel tree to be initialized with Git\n"
return 1
fi
if ! git rev-parse --verify "$past_ref" > /dev/null 2>&1; then
printf 'error - invalid git reference "%s"\n' "$past_ref"
return 1
fi
if [ -n "$base_ref" ]; then
if ! git merge-base --is-ancestor "$past_ref" "$base_ref" > /dev/null 2>&1; then
printf 'error - "%s" is not an ancestor of base ref "%s"\n' "$past_ref" "$base_ref"
return 1
fi
if [ "$(git rev-parse "$base_ref")" = "$(git rev-parse "$past_ref")" ]; then
printf 'error - "%s" and "%s" are the same reference\n' "$past_ref" "$base_ref"
return 1
fi
fi
}
run() {
local base_ref="$1"
local past_ref="$2"
local abi_error_log="$3"
shift 3
if [ -z "$KERNEL_SRC" ]; then
KERNEL_SRC="$(realpath "$(dirname "$0")"/..)"
fi
cd "$KERNEL_SRC"
if [ -z "$base_ref" ] && ! tree_is_dirty; then
base_ref=HEAD
fi
if [ -z "$past_ref" ]; then
if [ -n "$base_ref" ]; then
past_ref="${base_ref}^1"
else
past_ref=HEAD
fi
fi
if ! check_deps; then
exit "$FAIL_PREREQ"
fi
TMP_DIR=$(mktemp -d)
readonly TMP_DIR
trap 'rm -rf "$TMP_DIR"' EXIT
readonly INCOMPAT_LIST="${TMP_DIR}/incompat_list.txt"
touch "$INCOMPAT_LIST"
readonly SUPPRESSIONS="${TMP_DIR}/suppressions.txt"
gen_suppressions > "$SUPPRESSIONS"
# Run make install_headers for both refs
install_headers "$base_ref" "$past_ref"
# Check for any differences in the installed header trees
if diff -r -q "$(get_header_tree "$base_ref")" "$(get_header_tree "$past_ref")" > /dev/null 2>&1; then
printf "No changes to UAPI headers were applied between %s and %s\n" "$past_ref" "${base_ref:-dirty tree}"
exit "$SUCCESS"
fi
if ! check_uapi_files "$base_ref" "$past_ref" "$abi_error_log"; then
exit "$FAIL_ABI"
fi
}
main() {
MAX_THREADS=$(nproc)
VERBOSE="false"
IGNORE_AMBIGUOUS_CHANGES="false"
quiet="false"
local base_ref=""
while getopts "hb:p:j:l:iqv" opt; do
case $opt in
h)
print_usage
exit "$SUCCESS"
;;
b)
base_ref="$OPTARG"
;;
p)
past_ref="$OPTARG"
;;
j)
MAX_THREADS="$OPTARG"
;;
l)
abi_error_log="$OPTARG"
;;
i)
IGNORE_AMBIGUOUS_CHANGES="true"
;;
q)
quiet="true"
VERBOSE="false"
;;
v)
VERBOSE="true"
quiet="false"
;;
*)
exit "$FAIL_PREREQ"
esac
done
if [ "$quiet" = "true" ]; then
exec > /dev/null 2>&1
fi
run "$base_ref" "$past_ref" "$abi_error_log" "$@"
}
main "$@"
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