Mini Shell

#!/usr/bin/sh
#                          -*- mode: shell-script; sh-shell: "/bin/sh" -*-
# Copyright (C) 2018, 2021 g10 Code GmbH
#
# This file is free software; as a special exception the author gives
# unlimited permission to copy and/or distribute it, with or without
# modifications, as long as this notice is preserved.
#
# This file is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# SPDX-License-Identifier: FSFULLR

#### start of functions for this script

#
# Bourne shell functions for config file in pkg-config style, so that
# we can share such a config file between pkg-config and script
#

#
# get_var: Get the variable value of NAME
#
# Variables are recorded in the shell variables named "VAR_<NAME>"
#
get_var () {
    ___name=$1

    eval echo \$VAR_$___name
}

#
# get_attr: Get the attribute value of KEY
#
# Attributes are recorded in the shell variables named "ATTR_<KEY>"
#
get_attr () {
    ___name=$1

    eval echo \$ATTR_$___name
}

# variant of get_attr for list (separated by ',')
get_attr_l () {
    (IFS=', '; echo "$(get_attr $1)")
}

# Remove ${varname} part in the beginning of a string.
remove_var_expr () {
    ___varname=$1
    shift

    expr "$*" : "\${$___varname}\\(.*\\)"
}

# Given a string, substitute variables.
substitute_vars () {
    __string="$1"
    __varname=""
    __result=""

    while [ -n "$__string" ]; do
	case "$__string" in
	    \$\$*)
		__result="$__result\$"
		__string="${__string#\$\$}"
		;;
	    \${*}*)
		__varname="${__string#\$\{}"
		__varname="${__varname%%\}*}"
		__result="$__result$(get_var $__varname)"
		__string=$(remove_var_expr $__varname $__string)
		;;
	    *)
		__result="$__result$(printf %c "$__string")"
		__string="${__string#$(printf %c "$__string")}"
		;;
	esac
    done

    echo "$__result"
}

#
# Read a config from stdin
#
# Variables:
# For VAR=VALUE, value is stored in the shell variable VAR_*.
#
# Attributes:
# For KEY: VALUE, value is stored in the shell variable ATTR_*.
#
read_config_from_stdin () {
    _filename=$1
    _line=""
    _varname=""
    _value=""
    _key=""
    _reading_attrs=""

    while read _line; do
	if [ -z "$_line" ]; then
	    _reading_attrs=yes
	    continue
	elif [ -z "$_reading_attrs" ]; then
	    case "$_line" in
		*=*)
		    _varname="${_line%%=*}"
		    _value="${_line#*=}"
		    VAR_list="$VAR_list${VAR_list:+ }VAR_$_varname"
		    read VAR_$_varname <<EOF1
$(substitute_vars "$_value")
EOF1
		    continue
		    ;;
		*) _reading_attrs=yes ;;
	    esac
	fi
	if [ -n "$_reading_attrs" ]; then
	    case "$_line" in
		*:\ *)
		    _key="${_line%%:\ *}"
		    _value="${_line#*:\ }"
		    if expr "$_key" : ".*\..*" >/dev/null; then
			_key="${_key%.*}_${_key#*.}"
		    fi
		    ATTR_list="$ATTR_list${ATTR_list:+ }ATTR_$_key"
		    read ATTR_$_key <<EOF2
$(substitute_vars "$_value")
EOF2
		    ;;
		*:|*:\ ) ;;
		*)
		    echo "Error reading $_filename: $_line" 1>&2
		    exit 1
		    ;;
	    esac
	fi
    done
}


find_file_in_path () {
    _f=$1
    _p=$2
    _saved_IFS="$IFS"
    _arg=""
    IFS=":"		# On Windows it should be ";"???

    for _arg in $_p; do
	if [ -r $_arg/$_f ]; then
	    RESULT="$_arg/$_f"
	    IFS="$_saved_IFS"
	    return 0
	fi
    done
    IFS="$_saved_IFS"
    RESULT=""
    return 1
}

read_config_file () {
    if ! find_file_in_path $1.pc $2; then
	if [ -z "$want_exists" ]; then
	    echo "Can't find $1.pc" 1>&2
	fi
	exit 1
    fi
    read_config_from_stdin $RESULT < $RESULT
}

cleanup_vars_attrs () {
    eval unset $VAR_list VAR_list
    eval unset $ATTR_list ATTR_list
}

not_listed_yet () {
    ___m=$1
    ___arg=""
    shift

    for ___arg; do
	if [ $___m = $___arg ]; then
	    return 1
	fi
    done

    return 0
}

list_only_once () {
    __result=""
    __arg=""

    for __arg; do
	if not_listed_yet $__arg $__result; then
	    __result="$__result${__result:+ }$__arg"
	fi
    done

    echo $__result
}

list_only_once_for_libs () {
    __result=""
    __rev_list=""
    __arg=""

    # Scan the list and eliminate duplicates for non-"-lxxx"
    # the resulted list is in reverse order
    for __arg; do
	case "$__arg" in
	    -l*)
		# As-is
		__rev_list="$__arg${__rev_list:+ }$__rev_list"
		;;
	    *)
		if not_listed_yet $__arg $__rev_list; then
		    __rev_list="$__arg${__rev_list:+ }$__rev_list"
		fi
		;;
	esac
    done

    # Scan again
    for __arg in $__rev_list; do
	case "$__arg" in
	    -l*)
		if not_listed_yet $__arg $__result; then
		    __result="$__arg${__result:+ }$__result"
		fi
		;;
	    *)
		# As-is
		__result="$__arg${__result:+ }$__result"
		;;
	esac
    done

    echo $__result
}

arg1_is_same () {
    [ "$1" = "=" -o "$1" = ">=" -o "$1" = "<=" ]
}

arg1_is_less () {
    [ "$1" = "!=" -o "$1" = "<" -o "$1" = "<=" ]
}

arg1_is_great () {
    [ "$1" = "!=" -o "$1" = ">" -o "$1" = ">=" ]
}

#
# Evaluate comparison between versions in RPM way
#
eval_compare_version () {
    ___str1="$1"
    ___cmp="$2"
    ___str2="$3"
    ___char1=""
    ___char2=""
    ___chunk1=""
    ___chunk2=""

    while [ -n "$___str1" -a -n "$___str2" ]; do
	# Trim anything that's not alnum or tilde from the front
	___str1="$(expr "$___str1" : '[^0-9A-Za-z~]*\(.*\)')"
	___str2="$(expr "$___str2" : '[^0-9A-Za-z~]*\(.*\)')"

	# Get the first character
	___char1=${___str1%${___str1#?}}
	___char2=${___str2%${___str2#?}}

	if [ "$___char1" = ~ -o "$___char2" = ~ ]; then
	    if [ "$___char1" != ~ ]; then
		arg1_is_great $___cmp
		return
	    fi
	    if [ "$___char2" != ~ ]; then
		arg1_is_less $___cmp
		return
	    fi
	    ___str1=${___str1#~}
	    ___str2=${___str2#~}
	    continue
	fi

	if [ -z "$___char1" -o -z "$___char2" ]; then
	    break
	fi

	case "$___char1$___char2" in
	    [0-9][A-Za-z])
		arg1_is_great $___cmp
		return
		;;
	    [A-Za-z][0-9])
		arg1_is_less $___cmp
		return
		;;
	    [0-9][0-9])
		___chunk1="$(expr "$___str1" : '\([0-9]*\)')"
		___chunk2="$(expr "$___str2" : '\([0-9]*\)')"
		;;
	    [A-Za-z][A-Za-z])
		___chunk1="$(expr "$___str1" : '\([A-Za-z]*\)')"
		___chunk2="$(expr "$___str2" : '\([A-Za-z]*\)')"
		;;
	esac

	# Compare chunks numerically if digits, or lexicographically
	if expr "$___chunk1" "!=" "$___chunk2" >/dev/null; then
	    if expr "$___chunk1" ">" "$___chunk2" >/dev/null; then
		arg1_is_great $___cmp
		return
	    else
		arg1_is_less $___cmp
		return
	    fi
	fi

	# Remove the chunk
	___str1="${___str1#$___chunk1}"
	___str2="${___str2#$___chunk2}"
    done

    # Either STR1, STR2 or both is empty here
    if [ -n "$___str1" ]; then
	case "$___str1" in
	    ~*) arg1_is_less $___cmp ;;
	    *)  arg1_is_great $___cmp ;;
	esac
    elif [ -n "$___str2" ]; then
	case "$___str2" in
	    ~*) arg1_is_great $___cmp ;;
	    *)  arg1_is_less $___cmp ;;
	esac
    else
	arg1_is_same $___cmp
    fi
}

#
# Recursively solve package dependencies
#
# Result is in the PKG_LIST variable
#
all_required_config_files () {
    all_list=""
    new_list=""
    p=""
    pkg=""
    cmp=""

    list=$*
    while [ -n "$list" ]; do
	for p in $list; do
	    if [ -z "$pkg" ]; then
		pkg=$p
	    elif [ -z "$cmp" ]; then
		case "$p" in
		    "="|"!="|"<"|">"|"<="|">=") cmp=$p ;;
		    *)
			read_config_file $pkg $PKG_CONFIG_PATH
			all_list="$all_list${all_list:+ }$pkg"
			new_list="$new_list${new_list:+ }$(get_attr_l Requires)"
			if [ -n "$enable_static" ]; then
			    new_list="$new_list${new_list:+ }$(get_attr_l Requires_private)"
			fi
			cleanup_vars_attrs
			pkg=$p
			;;
		esac
	    else
		read_config_file $pkg $PKG_CONFIG_PATH
		if ! eval_compare_version "$(get_attr Version)" $cmp $p; then
		    echo "Version mismatch for $pkg $cmp $p: $(get_attr Version)" 1>&2
		    exit 1
		fi
		all_list="$all_list${all_list:+ }$pkg"
		new_list="$new_list${new_list:+ }$(get_attr_l Requires)"
		if [ -n "$enable_static" ]; then
		    new_list="$new_list${new_list:+ }$(get_attr_l Requires_private)"
		fi
		cleanup_vars_attrs
		pkg=""
		cmp=""
	    fi
	done
	if [ -n "$cmp" ]; then
	    echo "No version after comparison operator ($cmp): $pkg" 1>&2
	    exit 1
	elif [ -n "$pkg" ]; then
	    read_config_file $pkg $PKG_CONFIG_PATH
	    all_list="$all_list${all_list:+ }$pkg"
	    new_list="$new_list${new_list:+ }$(get_attr_l Requires)"
	    if [ -n "$enable_static" ]; then
		new_list="$new_list${new_list:+ }$(get_attr_l Requires_private)"
	    fi
	    cleanup_vars_attrs
	fi

	list="$new_list"
	new_list=""
    done

    PKG_LIST=$(list_only_once $all_list)
}

#
# Modify -I or -L by PKG_CONFIG_SYSROOT_DIR variable
#
sysroot () {
    _opt="$1"
    _result=""
    shift

    while [ $# -gt 0 ]; do
	if [ $1 = $_opt ]; then
	    _result="$_result${_result:+ }$_opt"
	    shift
	    _result="$_result $PKG_CONFIG_SYSROOT_DIR$1"
	elif expr "x$1" : "^x$_opt" >/dev/null; then
	    _result="$_result${_result:+ }$_opt$PKG_CONFIG_SYSROOT_DIR$(expr "x$1" : "^x$_opt\(.*\)")"
	else
	    _result="$_result${_result:+ }$1"
	fi
	shift
    done
    echo "$_result"
}

# Show usage
usage () {
    cat <<EOF
Usage: gpgrt-config [--libdir=LIBDIR] [OPTIONS] MODULES
Options:
	[--exists]
	[--modversion]
	[--libs]
	[--cflags]
	[--static]
	[--variable=VARNAME]
EOF
    exit $1
}
#### end of functions for this script

myname=${0##*/}
if [ $myname = gpgrt-config ]; then
  default_module="gpg-error"
else
  default_module=${myname%-config}
fi

# First stage to process --libdir option

libdir=""
while test $# -gt 0; do
    case $1 in
	--libdir=*)
	    libdir=${1#--libdir=}
	    shift
	    ;;
	*)
	    break
	    ;;
    esac
done

if [ x"${PKG_CONFIG_LIBDIR:+set}" = xset -a -z "$PKG_CONFIG_LIBDIR" ]; then
  # The variable set as empty, we use PKG_CONFIG_PATH in this case,
  # ignoring --libdir option
  if [ -z "$PKG_CONFIG_PATH"  ]; then
    echo "Please have valid PKG_CONFIG_PATH if PKG_CONFIG_LIBDIR is empty" 1>&2
    exit 1
  fi
else
  if [ -n "$libdir" ]; then
    # --libdir option is available, it overrides existing PKG_CONFIG_LIBDIR
    PKG_CONFIG_LIBDIR=$libdir/pkgconfig
  fi
  if [ -z "$PKG_CONFIG_LIBDIR" ]; then
    if [ -z "$PKG_CONFIG_PATH" ]; then
      echo "Please use --libdir=LIBDIR option or set PKG_CONFIG_LIBDIR" 1>&2
      echo "Or set PKG_CONFIG_PATH" 1>&2
      exit 1
    fi
  else
    # PKG_CONFIG_LIBDIR is available here
    # Modify PKG_CONFIG_PATH, prepending PKG_CONFIG_LIBDIR
    PKG_CONFIG_PATH="$PKG_CONFIG_LIBDIR${PKG_CONFIG_PATH:+:}$PKG_CONFIG_PATH"
  fi
fi
# PKG_CONFIG_PATH is ready here

#

if test $# -eq 0; then
    usage 1 1>&2
fi


# Second stage to do the main functionality

module_list=""
want_var=""
want_attr=""
want_cflags=""
want_libs=""
want_exists=""
enable_static=""

cflags=""
libs=""
mtcflags=""
mtlibs=""

output=""

mt="no"

VAR_list=VAR_pc_sysrootdir
if [ -z "$PKG_CONFIG_SYSROOT_DIR" ]; then
    VAR_pc_sysrootdir="/"
else
    VAR_pc_sysrootdir="$PKG_CONFIG_SYSROOT_DIR"
fi

while test $# -gt 0; do
    case $1 in
	#### pkg-config incompatible options: begin
	--prefix)
	    # In future, use --variable=prefix instead.
	    want_var=prefix
	    ;;
	--exec-prefix)
	    # In future, use --variable=exec_prefix instead.
	    want_var=exec_prefix
	    ;;
	--version)
	    # In future, use --modversion instead.
	    want_attr=Version
	    ;;
	--api-version)
	    # In future, use --variable=api_version instead.
	    want_var=api_version
	    ;;
	--host)
	    # In future, use --variable=host instead.
	    want_var=host
	    ;;
	--mt)
	    # In future, use --variable=mtcflags or --variable=mtlibs.
	    mt=yes
	    ;;
	#### pkg-config incompatible options: end
	--modversion)
	    want_attr=Version
	    ;;
	--exists)
	    want_exists=yes
	    ;;
	--cflags)
	    want_cflags=yes
	    ;;
	--libs)
	    want_libs=yes
	    ;;
	--static)
	    enable_static=yes
	    ;;
	--variable=*)
	    want_var=${1#*=}
	    ;;
	--help)
	    usage 0
	    ;;
	--*)
	    usage 1 1>&2
	    ;;
	*)
	    # Modules
	    module_list="$module_list${module_list:+ }$1"
	    ;;
    esac

    shift
done


if [ -z "$module_list" ]; then
    module_list=$default_module
elif expr "$module_list" : "=\|!=\|<\|>\|<=\|>=" >/dev/null; then
    module_list="$default_module $module_list"
fi

all_required_config_files $module_list

for p in $PKG_LIST; do
    read_config_file $p $PKG_CONFIG_PATH
    # For want_var or want_attr, get it from the first package
    if [ -n "$want_var" ]; then
	output="$(get_var $want_var)"
	break
    elif [ -n "$want_attr" ]; then
	output="$(get_attr $want_attr)"
	break
    else
	cflags="$cflags${cflags:+ }$(get_attr Cflags)"
	libs="$libs${libs:+ }$(get_attr Libs)"
	if [ -n "$enable_static" ]; then
	    libs="$libs${libs:+ }$(get_attr Libs_private)"
	fi

	if [ $p = "gpg-error" ]; then
	    mtcflags="$(get_var mtcflags)"
	    mtlibs="$(get_var mtlibs)"
	fi
    fi
    cleanup_vars_attrs
done

if [ -z "$want_var" -a -z "$want_attr" ]; then
    if [ -n "$want_cflags" ]; then
	output="$output${output:+ }$(sysroot -I $(list_only_once $cflags))"
	# Backward compatibility to old gpg-error-config
	if [ $mt = yes -a -n "$mtcflags" ]; then
	    output="$output${output:+ }$mtcflags"
	fi
    fi
    if [ -n "$want_libs" ]; then
	output="$output${output:+ }$(sysroot -L $(list_only_once_for_libs $libs))"
	# Backward compatibility to old gpg-error-config
	if [ $mt = yes -a -n "$mtlibs" ]; then
	    output="$output${output:+ }$mtlibs"
	fi
    fi
fi

if [ -z "$want_exists" ]; then
  echo "$output"
fi

exit 0