#!/bin/bash
#
# Copyright (c) 2014 Michael Palimaka <kensington@gentoo.org>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# A tool to report both undeclared and potentially-unused runtime dependencies.
#
# Depends on app-misc/pax-utils, app-portage/portage-utils and
# sys-apps/gentoo-functions.

DEBUG=FALSE
IGNORE_DEPS=( "sys-libs/glibc" "sys-devel/gcc" )
IGNORE_LINKS=( "/lib64/libgcc_s.so.1" )
PKG_DIR="/var/db/pkg/"

. /lib/gentoo/functions.sh

bold() {
	echo $@
	return
	local bold=$(tput bold)
	local normal=$(tput sgr0)
	echo "${bold}${@}${normal}"
}

debug() {
	if [ $DEBUG = TRUE ]; then
		# write to stderr so as not to interfere with function returns
		echo "$@" 1>&2
	fi
}

# app-foo/bar-1.2.3-r1 -> app-foo/bar
remove_atom_version() {
	local atom=`qatom "${1}" | cut -d " " -f 1-2 | tr " " /`
	echo $atom
}

virtualcheck() {
	debug Checking if ${libowner_pn} is provided by a virtual
	for virtual in $(qdepends --nocolor --name-only --rdepend --query ${libowner_pn} | grep ^virtual/)
	do
		debug Checking if ${virtual} is in dependencies
		local isvirtualdep
		isvirtualdep=$(qdepends --${1} ${atom} | grep ${virtual})

		if [ $? -eq 0 ]; then
			used_virtuals+=( ${virtual} )
			local resolved=true
			break
		fi
	done

	if [[ ! ${resolved} ]]; then
		if [ "${1}" = "depend" ]; then
			eerror "${obj} links to ${link}"
		fi
		eindent
		eerror Missing ${1^^} on $(bold ${libowner_pn})
		eoutdent
	fi

	errors=1
}

check_atom() {

	local errors=0
	local atom=$1
	local checked=()
	local rdepends=()
	local used_virtuals=()

	local objects=`qlist -qo ${atom}`

	if [ ! "${objects}" ]; then
		einfo ${atom} does not have any objects installed, skipping...
		echo
		return
	fi

	if [ -z "${INSIDE_PORTAGE}" ]; then
		einfo Checking ${atom} for undeclared dependencies
		eindent
	fi

	local obj
	for obj in $objects
	do
		debug "Checking ${obj}"

		readelf -h ${obj} > /dev/null 2>&1

		# can it have stuff linked to it?
		if [ $? -ne 0 ]; then
			debug "It can't have links, skipping"
			continue
		fi

		local elf=`scanelf --format "#f%n" --nobanner --use-ldpath ${obj} 2>&1`
		local links=`echo ${elf} | tr "," " "`

		# get a list of everything that it's linked to
		local link
		for link in $links
		do
			local ignore
			for ignore in "${IGNORE_LINKS[@]}"; do
				if [ "${ignore}" = "${link}" ]; then
					debug "Ignoring ${link} due to blacklist"
					continue 2
				fi
			done

			# only check a library once per atom for performance reasons
			local check
			for check in "${checked[@]}"; do
				if [ "${check}" = "${link}" ]; then
					debug "Already checked ${link} for this atom, skipping"
					continue 2
				fi
			done

			checked=( "${checked[@]}" "${link}" )

			debug "Found ${link}"

			local libowner=`qfile -vqC ${link} | uniq`

			if [ ! "${libowner}" ]; then
				local dereferenced=`qfile -vqC $(readlink -f ${link}) | uniq`
				if [ "${dereferenced}" ]; then
					debug "Deferenced symlink and found real lib owner"
					libowner=${dereferenced}
				else
					ewarn "Warning: installed file ${obj} is linked to ${link} which is not owned by any installed atom."
					continue
				fi
			fi

			debug "Owning package for ${link} is ${libowner}"

			local libowner_pn=$(remove_atom_version ${libowner})
			local my_pn=$(remove_atom_version ${atom})

			rdepends+=( "${libowner_pn}" )

			if [ "${libowner_pn}" = "${my_pn}" ]; then
				debug "Owning package is self, ignoring"
				continue
			fi

			local ignorelib
			for ignorelib in "${IGNORE_DEPS[@]}"
			do
				if [ "${libowner_pn}" = "${ignorelib}" ]; then
					debug "Ignoring objects belonging to ${ignorelib}"
					continue 2
				fi
			done

			debug "Checking if ${libowner_pn} is in the [R]DEPEND list of ${atom}"

			local isdep
			isdep=`qdepends -d ${atom} | grep ${libowner_pn}`
			if [ $? -ne 0 ]; then
				virtualcheck depend
			fi

			local isrdep
			isrdep=`qdepends -r ${atom} | grep ${libowner_pn}`
			if [ $? -ne 0 ]; then
				virtualcheck rdepend
			fi


		done

	done

	local ebuild_rdepends=()
	for rdepend in $(qdepends --nocolor --quiet --rdepend ${atom} | sed -e "s/\[[^]]*\]//g" | cut -d : -f 2-)
	do
		if [[ ${rdepend} = !* ]] ; then
			debug Skipping blocker: ${rdepend}
			continue
		elif [[ ${rdepend} = virtual/* ]] ; then
			for virtual in "${used_virtuals[@]}"
			do
				if [[ ${virtual} == $(remove_atom_version ${rdepend}) ]]; then
					debug Skipping virtual: ${rdepend}
					continue 2
				fi
			done
		fi
		ebuild_rdepends+=( $(remove_atom_version $rdepend) )
	done

	debug "Ebuild RDEPENDS: ${ebuild_rdepends[@]}"
	debug "Linked RDEPENDS: ${rdepends[@]}"

	local suspect_rdepends=$(comm -13 <(echo ${rdepends[@]} | sed 's/ /\n/g' | sort -u) <(echo ${ebuild_rdepends[@]} | sed 's/ /\n/g' | sort -u))
	if [ "${suspect_rdepends}" ]; then
		ewarn "Suspect RDEPEND: $(bold ${suspect_rdepends})"
	fi

	if [ -z "${INSIDE_PORTAGE}" ]; then
		eoutdent
		if [ -n "${CAT}" ]; then
			echo
		fi
	fi

	return $errors

}

check_package() {

	local package=$1
	local atoms=`qlist -IcCS ${package} | tr ' ' '-' | cut -d : -f1`

	debug Package ${package} own atoms: ${atoms}

	if [ ! "${atoms}" ]; then
		eerror ERROR: ${package} is not a valid atom
		exit 1
	fi

	for atom in ${atoms}; do
		check_atom ${atom}
	done

}

check_category() {

	local errors=0

	for package in `ls "${PKG_DIR}/${1}"`; do

		check_package "${1}/${package}"

		if [ $? -ne 0 ]; then
			errors=1
		fi

	done;

	return $errors

}

BINNAME=`basename ${0}`
if [ -z $1 ]; then
	echo "Checks emerged package(s) for undeclared depedencies"
	echo
        echo "Usage: ${BINNAME} [ atom | -c category | -a ]"
	echo
        echo "Examples:"
	echo "Check a single package: ${BINNAME} app-foo/bar-1.2.3"
	echo "Check a category: ${BINNAME} -c app-foo"
	echo "Check everything: ${BINNAME} -a"
	exit 1
fi

# check a particular category
if [ "$1" = "-c" ]; then

	CAT=$2

	if [ ! -d "${PKG_DIR}/${CAT}" ]; then
		eerror ERROR: No packages from the category ${CAT} have been emerged yet
		exit 1
	fi

	check_category $CAT

# check everything
elif [ "$1" = "-a" ]; then

	for category in `ls ${PKG_DIR}`; do
		check_category $category
	done;

else
	check_package $1
fi

if [ $DEBUG = TRUE ]; then
	if [ $? -eq 0 ]; then
		einfo Checking complete, no errors found
	else
		eerror Checking complete, errors found
	fi
fi