| 1 | #!/usr/bin/env bash |
| 2 | # SPDX-License-Identifier: GPL-2.0-only |
| 3 | # |
| 4 | # Copyright (C) 2022 Masahiro Yamada <[email protected]> |
| 5 | # |
| 6 | # Exit with error if a local exported symbol is found. |
| 7 | # EXPORT_SYMBOL should be used for global symbols. |
| 8 | |
| 9 | set -e |
| 10 | |
| 11 | # catch errors from ${NM} |
| 12 | set -o pipefail |
| 13 | |
| 14 | # Run the last element of a pipeline in the current shell. |
| 15 | # Without this, the while-loop would be executed in a subshell, and |
| 16 | # the changes made to 'symbol_types' and 'export_symbols' would be lost. |
| 17 | shopt -s lastpipe |
| 18 | |
| 19 | declare -A symbol_types |
| 20 | declare -a export_symbols |
| 21 | |
| 22 | exit_code=0 |
| 23 | |
| 24 | # If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows |
| 25 | # 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by |
| 26 | # '2>/dev/null'. However, it suppresses real error messages as well. Add a |
| 27 | # hand-crafted error message here. |
| 28 | # |
| 29 | # TODO: |
| 30 | # Use --quiet instead of 2>/dev/null when we upgrade the minimum version of |
| 31 | # binutils to 2.37, llvm to 13.0.0. |
| 32 | # Then, the following line will be really simple: |
| 33 | # ${NM} --quiet ${1} | |
| 34 | |
| 35 | { ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; false; } } | |
| 36 | while read value type name |
| 37 | do |
| 38 | # Skip the line if the number of fields is less than 3. |
| 39 | # |
| 40 | # case 1) |
| 41 | # For undefined symbols, the first field (value) is empty. |
| 42 | # The outout looks like this: |
| 43 | # " U _printk" |
| 44 | # It is unneeded to record undefined symbols. |
| 45 | # |
| 46 | # case 2) |
| 47 | # For Clang LTO, llvm-nm outputs a line with type 't' but empty name: |
| 48 | # "---------------- t" |
| 49 | if [[ -z ${name} ]]; then |
| 50 | continue |
| 51 | fi |
| 52 | |
| 53 | # save (name, type) in the associative array |
| 54 | symbol_types[${name}]=${type} |
| 55 | |
| 56 | # append the exported symbol to the array |
| 57 | if [[ ${name} == __ksymtab_* ]]; then |
| 58 | export_symbols+=(${name#__ksymtab_}) |
| 59 | fi |
| 60 | done |
| 61 | |
| 62 | for name in "${export_symbols[@]}" |
| 63 | do |
| 64 | # nm(3) says "If lowercase, the symbol is usually local" |
| 65 | if [[ ${symbol_types[$name]} =~ [a-z] ]]; then |
| 66 | echo "$@: error: local symbol '${name}' was exported" >&2 |
| 67 | exit_code=1 |
| 68 | fi |
| 69 | done |
| 70 | |
| 71 | exit ${exit_code} |