# sysdeps common
#
# Written in 2020 by Francesco Palumbo phranz@subfc.net
#
# To the extent possible under law, the author(s) have dedicated 
# all copyright and related and neighboring rights to this software 
# to the public domain worldwide. 
# This software is distributed without any warranty.
# You should have received a copy of the CC0 Public Domain Dedication 
# along with this software. 
# If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.


LDCONFPATH = '/etc/ld.so.conf'

DEPMARK = 'NEEDED'.freeze
ELF = 'ELF'.freeze
SYM = 'symbolic'.freeze
LINK = 'link'.freeze
EMPTY = ''.freeze


readlink_absolute = ->(path) {
    curdir = Dir.getwd
    Dir.chdir(File.dirname path)
    abs = File.absolute_path(File.readlink(File.basename path))
    Dir.chdir curdir 
    abs }


get_syslibs = ->(paths) {
    ldconf_paths = File.file?(LDCONFPATH) && File.readable?(LDCONFPATH) ? File.read(LDCONFPATH).split : []
    ldpaths = ldconf_paths.union(paths).join ' '
    sopat = /\.so\.?/

    %x(find #{ldpaths} \\( -type f -o -type l \\) 2>/dev/null)
        .split
        .select { |l| 
            l[sopat] }
        .map { |l| 
            File.ftype(l) == LINK ? [l, readlink_absolute(l)] : l }
        .flatten }


get_program_dependencies = ->(prg) {
    return prg if not prg
    prgpath = nil

    prgpath = File.exist?(prg) ? prg : %x(which #{prg} 2>/dev/null).chomp
    
    return nil unless File.exist?(prgpath)
    
    prgpath = readlink_absolute(prgpath) if File.ftype(prgpath) == LINK
    
    return nil if %x(file #{prgpath}).split[1] != ELF

    deppat = /\s+#{DEPMARK}\s+/
    %x(objdump -p #{prgpath})
        .split("\n")
        .select { |r| r.include? DEPMARK }
        .map { |r| r.gsub(deppat, EMPTY) }}


get_programs_dependencies = ->() {
    prog_deps = {}
    deppat = /\s+#{DEPMARK}\s+/
    paths = ENV['PATH'].split(':').join(' ')

    IO.popen("find #{paths} -type f -executable 2>/dev/null") { |find_io|
        find_io.each_with_object({}) { |l, o|
            next if %x{file #{l}}.split[1] != ELF

            o[l.chomp] = 
                %x{objdump -p #{l}}
                .split("\n")
                .select { |r| r.include? DEPMARK }
                .map { |r| r.gsub(deppat, EMPTY) }}}}


get_libraries_dependencies = ->(syslibs) {
    deppat = /\s+#{DEPMARK}\s+/
    
    syslibs.each_with_object({}) { |sl, o|
        sl = readlink_absolute(sl) if File.ftype(sl) == LINK

        next if %x{file #{sl}}.split[1] != ELF

        o[sl.chomp] = 
            %x{objdump -p #{sl}}
            .split("\n")
            .select { |r| r.include? DEPMARK }
            .map { |r| r.gsub(deppat, EMPTY) }}}


get_programs_by_deps = ->(prog_deps, pattern) {
    rex = Regexp.new pattern, Regexp::IGNORECASE

    prog_deps.each_with_object({}) { |(prog, deps), o|
        deps.each { |d|
            if d[rex]
                lms = $~.string
                o[lms] ? o[lms] << prog : o[lms] = [prog]
            end }}}


get_total_deps = ->(deps) { deps.values.flatten.uniq }


get_missing_libs = ->(syslibs, libs) {
    syslibs =  syslibs.map { |l| File.basename l }
    libs.select { |l| !syslibs.include? l }}


group_failed_by_lib = ->(deps, missing) {
    missing.each_with_object({}) { |l, o|
        o[l] = []

        deps.each { |prg, libs|
            o[l] << prg if libs.include? l }}}


SysDeps = Module.new { 
    local_variables.each { |f| 
        define_method(f, eval(f.to_s)) }}