#!/bin/sh # SPDX-License-Identifier: GPL-2.0-only # # Copyright (C) 2022 Masahiro Yamada <masahiroy@kernel.org> # Copyright (C) 2022 Owen Rafferty <owen@owenrafferty.com> # # Exit with error if a local exported symbol is found. # EXPORT_SYMBOL should be used for global symbols. set -e pid=$$ # If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows # 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by # '2>/dev/null'. However, it suppresses real error messages as well. Add a # hand-crafted error message here. # # TODO: # Use --quiet instead of 2>/dev/null when we upgrade the minimum version of # binutils to 2.37, llvm to 13.0.0. # Then, the following line will be simpler: # { ${NM} --quiet ${1} || kill 0; } | { ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; kill $pid; } } | ${AWK} -v "file=${1}" ' BEGIN { i = 0 } # Skip the line if the number of fields is less than 3. # # case 1) # For undefined symbols, the first field (value) is empty. # The outout looks like this: # " U _printk" # It is unneeded to record undefined symbols. # # case 2) # For Clang LTO, llvm-nm outputs a line with type t but empty name: # "---------------- t" !length($3) { next } # save (name, type) in the associative array { symbol_types[$3]=$2 } # append the exported symbol to the array ($3 ~ /^__ksymtab_/) { export_symbols[i] = $3 sub(/^__ksymtab_/, "", export_symbols[i]) i++ } END { exit_code = 0 for (j = 0; j < i; ++j) { name = export_symbols[j] # nm(3) says "If lowercase, the symbol is usually local" if (symbol_types[name] ~ /[a-z]/) { printf "%s: error: local symbol %s was exported\n", file, name | "cat 1>&2" exit_code = 1 } } exit exit_code }' exit $?