#!/usr/bin/env bash

# Copyright (C) 2016 Samuel Martin <s.martin49@gmail.com>
# Copyright (C) 2017 Wolfgang Grandegger <wg@grandegger.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

usage() {
  cat <<EOF >&2
Usage:  ${0} TREE_KIND

Description:

    This script scans a tree and sanitize ELF files' RPATH found in there.

    Sanitization behaves the same whatever the kind of the processed tree,
    but the resulting RPATH differs. The rpath sanitization is done using
    "patchelf --make-rpath-relative".

Arguments:

    TREE_KIND    Kind of tree to be processed.
                 Allowed values: host, target, staging

Environment:

    PATCHELF     patchelf program to use
                 (default: HOST_DIR/bin/patchelf)

    HOST_DIR     host directory
    STAGING_DIR  staging directory
    TARGET_DIR   target directory

    TOOLCHAIN_EXTERNAL_DOWNLOAD_INSTALL_DIR
                 (default HOST_DIR/opt/ext-toolchain)

    PARALLEL_JOBS number of parallel jobs to run

Returns:         0 if success or 1 in case of error

EOF
}

: "${PATCHELF:=${HOST_DIR}/bin/patchelf}"

# ELF files should not be in these sub-directories
HOST_EXCLUDEPATHS="/share/terminfo"
STAGING_EXCLUDEPATHS="/usr/include /usr/share/terminfo"
TARGET_EXCLUDEPATHS="/lib/firmware"

patch_file() {
    local PATCHELF rootdir file
    local -a sanitize_extra_args

    PATCHELF="${1}"
    rootdir="${2}"
    file="${3}"
    shift 3
    sanitize_extra_args=("${@}")

    # check if it's an ELF file
    rpath="$("${PATCHELF}" --print-rpath "${file}" 2>&1)"
    if test $? -ne 0 ; then
        return 0
    fi

    # make files writable if necessary
    changed="$(chmod -c u+w "${file}")"

    # With per-package directory support, most RPATH of host
    # binaries will point to per-package directories. This won't
    # work with the --make-rpath-relative ${rootdir} invocation as
    # the per-package host directory is not within ${rootdir}. So,
    # we rewrite all RPATHs pointing to per-package directories so
    # that they point to the global host directry.
    # shellcheck disable=SC2001 # ${var//search/replace} hard when search or replace have / in them
    changed_rpath="$(echo "${rpath}" | sed "s@${PER_PACKAGE_DIR}/[^/]\+/host@${HOST_DIR}@")"
    if test "${rpath}" != "${changed_rpath}" ; then
        "${PATCHELF}" --set-rpath "${changed_rpath}" "${file}"
    fi

    # call patchelf to sanitize the rpath
    "${PATCHELF}" --make-rpath-relative "${rootdir}" "${sanitize_extra_args[@]}" "${file}"
    # restore the original permission
    test "${changed}" != "" && chmod u-w "${file}"
}

main() {
    local rootdir tree
    local -a find_args sanitize_extra_args

    tree="${1}"

    if ! "${PATCHELF}" --version > /dev/null 2>&1; then
        echo "Error: can't execute patchelf utility '${PATCHELF}'"
        exit 1
    fi

    case "${tree}" in
        host)
            rootdir="${HOST_DIR}"

            # do not process the sysroot (only contains target binaries)
            find_args+=( "-path" "${STAGING_DIR}" "-prune" "-o" )

            # do not process the external toolchain installation directory to
            # avoid breaking it.
            test "${TOOLCHAIN_EXTERNAL_DOWNLOAD_INSTALL_DIR}" != "" && \
                find_args+=( "-path" "${TOOLCHAIN_EXTERNAL_DOWNLOAD_INSTALL_DIR}" "-prune" "-o" )

            for excludepath in ${HOST_EXCLUDEPATHS}; do
                find_args+=( "-path" "${HOST_DIR}""${excludepath}" "-prune" "-o" )
            done

            # do not process the patchelf binary but a copy to work-around "file in use"
            find_args+=( "-path" "${PATCHELF}" "-prune" "-o" )
            cp "${PATCHELF}" "${PATCHELF}.__to_be_patched"

            # we always want $ORIGIN-based rpaths to make it relocatable.
            sanitize_extra_args+=( "--relative-to-file" )
            ;;

        staging)
            rootdir="${STAGING_DIR}"

            # ELF files should not be in these sub-directories
            for excludepath in ${STAGING_EXCLUDEPATHS}; do
                find_args+=( "-path" "${STAGING_DIR}""${excludepath}" "-prune" "-o" )
            done

            # should be like for the target tree below
            sanitize_extra_args+=( "--no-standard-lib-dirs" )
            ;;

        target)
            rootdir="${TARGET_DIR}"

            for excludepath in ${TARGET_EXCLUDEPATHS}; do
                find_args+=( "-path" "${TARGET_DIR}""${excludepath}" "-prune" "-o" )
            done

            # we don't want $ORIGIN-based rpaths but absolute paths without rootdir.
            # we also want to remove rpaths pointing to /lib or /usr/lib.
            sanitize_extra_args+=( "--no-standard-lib-dirs" )
            ;;

        *)
            usage
            exit 1
            ;;
    esac

    find_args+=( "-type" "f" "-print0" )

    export -f patch_file
    # Limit the number of cores used
    # shellcheck disable=SC2016  # ${@} has to be expanded in the sub-shell.
    find "${rootdir}" "${find_args[@]}" \
    | xargs -0 -r -P "${PARALLEL_JOBS:-1}" -I {} \
            bash -c 'patch_file "${@}"' _ "${PATCHELF}" "${rootdir}" {} "${sanitize_extra_args[@]}"

    # Restore patched patchelf utility
    test "${tree}" = "host" && mv "${PATCHELF}.__to_be_patched" "${PATCHELF}"

    # ignore errors
    return 0
}

main "${@}"