diff options
| -rw-r--r-- | eshld/link.esh | 102 | ||||
| -rw-r--r-- | eshld/main.esh | 113 |
2 files changed, 215 insertions, 0 deletions
diff --git a/eshld/link.esh b/eshld/link.esh new file mode 100644 index 0000000..d01fc4d --- /dev/null +++ b/eshld/link.esh @@ -0,0 +1,102 @@ +# Eggshell Linker entry point +# +# Copyright (C) 2015 Patrick "P. J." McDermott +# +# This file is part of the Eggshell Linker. +# +# The Eggshell Linker 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 3 of +# the License, or (at your option) any later version. +# +# The Eggshell Linker 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 the Eggshell Linker If not, see +# <http://www.gnu.org/licenses/>. + +interpreter= +entry_point= +output= +make_executable= + +die() +{ + local fmt="${1}" + shift 1 + + printf "eshld: ${fmt}\n" "${@}" >&2 + exit 2 +} + +link_begin() +{ + local interp="${1}" + local entry="${2}" + local out="${3}" + local mkexec="${4}" + shift 4 + + interpreter="${interp}" + entry_point="${entry}" + output="${out}" + make_executable=${mkexec} + + # Open output file. + if ! exec 3>"${output}~"; then + die 'Cannot open file "%s"' "${output}~" + fi + + # Write magic number and interpreter path. + if ${make_executable}; then + printf '#!%s\n' "${interpreter}" >&3 + fi + + # Write __init() function. + cat >&3 <<-'EOF' + __init_funcs='' + __init() + { + __init_funcs="${__init_funcs} ${1}" + } + EOF + +} + +link_file() +{ + local input="${1}" + + if ! cat "${input}" >&3; then + die 'Cannot read file "%s"' "${input}" + fi +} + +link_end() +{ + # Add call to init functions. + cat >&3 <<-'EOF' + for __func in ${__init_funcs}; do + ${__func} + done + EOF + + # Add call to entry point. + if ${make_executable}; then + printf '%s "${@}"\n' "${entry_point}" >&3 + fi + + # Close output file, make it executable, and set its name. + exec 3>&- + if ${make_executable}; then + if ! chmod a+x "${output}~"; then + die 'Cannot set mode of file "%s"' "${output}~" + fi + fi + if ! mv "${output}~" "${output}"; then + die 'Cannot rename file to "%s"' "${output}" + fi +} diff --git a/eshld/main.esh b/eshld/main.esh new file mode 100644 index 0000000..775179f --- /dev/null +++ b/eshld/main.esh @@ -0,0 +1,113 @@ +# Eggshell Linker entry point +# +# Copyright (C) 2015 Patrick "P. J." McDermott +# +# This file is part of the Eggshell Linker. +# +# The Eggshell Linker 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 3 of +# the License, or (at your option) any later version. +# +# The Eggshell Linker 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 the Eggshell Linker If not, see +# <http://www.gnu.org/licenses/>. + +set -u + +VERSION='0.1.0' + +usage() +{ + printf 'Usage: %s [option ...] <file>...\n' "${0}" +} + +help() +{ + usage + cat <<EOF +Options: + -h Display this information + -V Display linker version information + -I <interp> Use <interp> as the interpreter for your program, instead of the + default of "/bin/sh" + -e <entry> Use <entry> as the function for beginning execution of your + program, instead of the default of "main" + -o <output> Use <output> as the name of the program produced by eshld, + instead of the default of "out.sh" +EOF +} + +version() +{ + cat <<EOF +eshld ${VERSION} +Copyright (C) 2015 Patrick "P. J." McDermott +License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. +This is free software: you are free to change and redistribute it. +There is NO WARRANTY, to the extent permitted by law. +EOF +} + +main() +{ + local opt= + local interpreter= + local entry_point= + local output= + local make_executable= + local input= + + interpreter='/bin/sh' + entry_point='main' + output='out.sh' + make_executable=true + + while getopts 'hVI:e:o:' opt; do + case "${opt}" in + 'h') + help + return 0 + ;; + 'V') + version + return 0 + ;; + 'I') + interpreter="${OPTARG}" + ;; + 'e') + entry_point="${OPTARG}" + ;; + 'o') + output="${OPTARG}" + ;; + esac + done + shift $(($OPTIND - 1)) + + if [ ${#} -lt 1 ]; then + usage >&2 + return 1 + fi + + if ! link_begin "${interpreter}" "${entry_point}" "${output}" \ + ${make_executable}; then + return 1 + fi + for input in "${@}"; do + if ! link_file "${input}"; then + return 1 + fi + done + if ! link_end; then + return 1 + fi + + return 0 +} |