#!/bin/bash

# Copyright (C) 2008 Steve Youngs

# Author:     Steve Youngs <steve@sxemacs.org>
# Maintainer: Steve Youngs <steve@sxemacs.org>
# Created:    <2008-03-10>
# Time-stamp: <Tuesday Apr  1, 2008 00:52:35 steve>
# Homepage:   N/A
# Keywords:   utils package-management

# This file is part of pkgusr.

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# 3. Neither the name of the author nor the names of any contributors
#    may be used to endorse or promote products derived from this
#    software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
# IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

## Commentary:
# 
#  This script is used to locate libraries that define a symbol
#  (function).  It comes in very handy when package builds fail with
#  "undefined reference..." errors.  By default, only defined syms
#  are searched for, but with -a option, all syms, both defined and
#  undefined are searched.
#
#  First, it tries with nm(1), and if that gets nowhere (like in the
#  case of stripped libraries), fall back on objdump(1).

## Code:
ourname=${0##*/}

# Usage
if [ $# -lt 1 -o "$1" = "--help" -o "$1" = "--usage" -o "$1" = "-h" ]; then
	echo 1>&2
	echo 1>&2 'USAGE:  ${ourname} [ -a ] <symbol_regexp>'
	echo 1>&2
	echo 1>&2 '  Find libraries that export symbol matching <symbol_regexp>.'
	echo 1>&2 '  By default, only libraries that define the symbol are reported.'
	echo 1>&2 '  With the '"'-a'"' option, libraries that have the symbol, but'
	echo 1>&2 '  it is undefined, or a debugging symbol, are also listed.'
	echo 1>&2
	echo 1>&2 '  See grep(1), '"'REGULAR EXPRESSIONS'"' for the syntax of regexps'
	echo 1>&2 '  used by this script.'
	echo 1>&2
	exit 1
fi

# Library directories.
# These are the directories we search.  If you have other lib directories
# such as /usr/local/lib, /opt/lib, add them here.
lib_dirs=(/usr/lib /usr/X11/lib /lib)

if [ "$1" = "-a" ]; then
    nm_opts="--demangle=gnu-v3 --debug-syms"
    shift
else
    nm_opts="--demangle=gnu-v3 --defined-only --dynamic"
fi
obj_opts="--demangle=gnu-v3 --reloc --dynamic-reloc --syms --dynamic-syms"

# $1 should now be the symbol (or symbol regexp) to search for
sym=${1}

all_libs=$(find -H -L ${lib_dirs[*]} -type f \( -name "lib*.so" -o -name "lib*.a" \) -print)

for lib in ${all_libs} ; do
    unset good_file lib_syms
    good_file="$(file ${lib}|grep \(\(shared object\)\|\(ar archive\)\) 2>/dev/null)"
    if [ -n "${good_file}" ]; then
	lib_syms=$(nm ${nm_opts} ${lib} 2>/dev/null)
	if [ -n "${lib_syms}" ]; then
	    echo ${lib_syms}|grep -E ${sym} 1>/dev/null && echo ${lib}
	else
	    objdump ${obj_opts} ${lib} 2>/dev/null |
	        grep -E ${sym} 1>/dev/null &&
	        echo ${lib}
	fi
    fi
done

## library-symbol-search ends here