#! /bin/sh

# Written by Zack Weinberg <zackw at panix.com> in 2017.

# To the extent possible under law, Zack Weinberg has waived all

# copyright and related or neighboring rights to this work.

#

# See https://creativecommons.org/publicdomain/zero/1.0/ for further

# details.

# This test is only run if we are building a shared library intended

# to be binary backward compatible with GNU libc (libcrypt.so.1).

# It locates any installed version of libcrypt.so.1, and verifies that

# each public symbol exposed by that library is also exposed by our

# libcrypt.so.1 with a matching symbol version.

#

# Due to limitations in Automake, this program takes parameters from

# the environment:

# $lib_la - full pathname of libcrypt.la

set -e

LC_ALL=C; export LC_ALL

get_symbols_with_versions ()

{

    nm -gD --with-symbol-versions "$1" |

        grep -v ' U ' | cut -d' ' -f3 |

        sed -e 's/@@*/ /; /^\([A-Z0-9_.]*\) \1$/d' |

        sort -u

}

get_our_symbols_with_versions ()

{

    eval $(grep dlname= "$1")

    get_symbols_with_versions "${1%/*}/.libs/${dlname}"

    unset dlname

}

get_their_symbols_with_versions ()

{

    (

        set -e

        cd "$1"

        cat >test.c <<\EOF

extern char *crypt(const char *, const char *);

int main(int argc, char **argv)

{

  return !!crypt(argv[0], argv[1]);

}

EOF

        ${CC-cc} test.c -lcrypt >&2 || exit 77

        if ldd ./a.out | grep -qF libcrypt.so.1; then

            get_symbols_with_versions $(ldd ./a.out | grep -F libcrypt.so.1 |

                                            cut -d' ' -f3)

        else

            exit 77

        fi

    )

    if [ $? -ne 0 ]; then exit $?; fi

}

if [ ! -f "$lib_la" ]; then

    echo "Usage: lib_la=/path/to/library.la $0" >&2

    exit 1

fi

# If 'nm' and/or 'ldd' are not available, this test will not work.

command -v nm > /dev/null 2>&1 || {

    echo "Error: 'nm' is unavailable" >&2

    exit 77

}

command -v ldd > /dev/null 2>&1 || {

    echo "Error: 'ldd' is unavailable" >&2

    exit 77

}

workdir=""

trap '[ -z "$workdir" ] || rm -rf "$workdir" || :' 0

workdir="$(mktemp -d)"

get_our_symbols_with_versions "$lib_la" > "$workdir/our_symbols"

get_their_symbols_with_versions "$workdir" > "$workdir/their_symbols"

# It's okay if we define more symbol (versions) than they do, but every

# symbol they define should have a matching definition in our library.

missing_symbols="$(comm -13 "$workdir/our_symbols" "$workdir/their_symbols")"

if [ -n "$missing_symbols" ]; then

    printf '*** Missing symbols: %s\n' "$missing_symbols" >&2

    exit 1

fi

exit 0