lxsh/src/debashify.cpp

#include "debashify.hpp"

#include "recursive.hpp"
#include "util.hpp"
#include "parse.hpp"
#include "struc_helper.hpp"

bool debashify_bashtest(cmd* in)
{
  if(in->firstarg_string() == "[[")
    throw std::runtime_error("Cannot debashify '[[ ]]'");

  return false;
}

bool debashify_declare(cmd* in)
{
  if(in->firstarg_string() == "declare")
    throw std::runtime_error("Cannot debashify 'declare'");
  return false;
}

bool debashify_array_def(cmd* in)
{
  for(auto it: in->var_assigns)
  {
    if(it.second->size()>0 && it.second->sa[0]->type == _obj::subarg_string && it.second->sa[0]->generate(0) == "(")
      throw std::runtime_error("Cannot debashify VAR=() variable arrays");
  }
  return false;
}

bool debashify_herestring(pipeline* pl)
{
  return false;
}

// replace &>, &>> and >&:
// add 2>&1 as redirect
bool debashify_combined_redirects(block* in)
{
  bool has_replaced=false;

  for(uint32_t i=0; i<in->redirs.size() ; i++)
  {
    if(in->redirs[i]->op == "&>" || in->redirs[i]->op == "&>>" || in->redirs[i]->op == ">&")
    {
      // resolve new operator
      std::string newop = ">";
      if( in->redirs[i]->op == "&>>" )
        newop = ">>";
      // create new redir with target
      redirect* newredir = new redirect(newop, in->redirs[i]->target);
      in->redirs[i]->target=nullptr;
      // replace old redir
      delete in->redirs[i];
      in->redirs[i] = newredir;
      // insert merge redir
      i++;
      in->redirs.insert(in->redirs.begin()+i, new redirect("2>&1"));

      has_replaced=true;
    }
  }

  return has_replaced;
}

// replace <<< and
// <<< : TODO
bool debashify_extended_redirects(pipeline* in)
{
  return false;
}

// replace <() and >()
/*
 <() replacer:
REPLACE: CMD <(PSUB)
TO:
  fifoN=${TMPDIR-/tmp}/lxshfifo_$(__lxsh_random 10)
  mkfifo "$fifoN"
  ( {PSUB;} > "$fifoN" ; rm "$fifoN") &
  CMD "$fifoN"

REPLACE CMD >(PSUB)
TO:
  fifoN=${TMPDIR-/tmp}/lxshfifo_$(__lxsh_random 10)
  mkfifo "$fifoN"
  ( {PSUB;} < "$fifoN" ; rm "$fifoN") &
  jobN
  CMD "$fifoN"
  wait "$jobN"
*/
bool debashify_procsub(list* lst)
{
  bool has_replaced=false;
  for(uint32_t li=0; li<lst->cls.size(); li++)
  {
    std::vector<std::pair<arg*,bool>> affected_args;
    // iterate all applicable args of the cl
    for(auto plit: lst->cls[li]->pls)
    {
      for(auto cmit: plit->cmds)
      {
        if(cmit->type == _obj::block_cmd)
        {
          cmd* t = dynamic_cast<cmd*>(cmit);
          if(t->args != nullptr)
          {
            for(auto ait: t->args->args)
            {
              if(ait->size() == 1 && ait->sa[0]->type == _obj::subarg_procsub)
              {
                procsub_subarg* st = dynamic_cast<procsub_subarg*>(ait->sa[0]);
                affected_args.push_back( std::make_pair(ait, st->is_output) );
              }
            }
          }
        }
      }
    }
    // perform the replace
    if(affected_args.size()>0)
    {
      has_replaced=true;
      list* lst_insert = new list;
      std::string mkfifocmd="mkfifo";
      for(uint32_t i=0; i<affected_args.size(); i++)
      {
        // fifoN=${TMPDIR-/tmp}/lxshfifo_$(__lxsh_random 10)
        lst_insert->add( make_condlist( strf("__lxshfifo%u=${TMPDIR-/tmp}/lxshfifo_$(__lxsh_random 10)", i) ) );
        mkfifocmd += strf(" \"$__lxshfifo%u\"", i);
      }
      // mkfifo "$fifoN"
      lst_insert->add( make_condlist(mkfifocmd) );
      for(uint32_t i=0; i<affected_args.size(); i++)
      {
        // create ( {PSUB;} > "$fifoN" ; rm "$fifoN") &
        subshell* psub = new subshell(new list);
        procsub_subarg* st = dynamic_cast<procsub_subarg*>(affected_args[i].first->sa[0]);
        // {PSUB;}
        brace* cbr = new brace(st->sbsh->lst);
        // deindex list
        st->sbsh->lst=nullptr;
        // {PSUB;} > "$__lxshfifoN"
        cbr->redirs.push_back( new redirect( affected_args[i].second ? "<" : ">", make_arg(strf("\"$__lxshfifo%u\"", i)) ) );
        // ( {PSUB;} > "$__lxshfifoN" )
        psub->lst->add( new condlist(cbr) );
        // ( {PSUB;} > "$__lxshfifoN" ; rm "$__lxshfifoN" )
        psub->lst->add( make_condlist(strf("rm \"$__lxshfifo%u\"", i)) );
        // ( {PSUB;} > "$__lxshfifoN" ; rm "$__lxshfifoN" ) &
        condlist* pscl = new condlist(psub);
        pscl->parallel=true;
        lst_insert->add( pscl );

        // replace the arg
        delete affected_args[i].first->sa[0];
        affected_args[i].first->sa[0] = new string_subarg("\"");
        affected_args[i].first->add( new variable_subarg(strf("__lxshfifo%u", i)) );
        affected_args[i].first->add( new string_subarg("\"") );
      }
      lst->insert(li, *lst_insert );
      li+= lst_insert->size();
      //cleanup
      lst_insert->cls.resize(0);
      delete lst_insert;
    }
  }
  return has_replaced;
}

function* create_random_func()
{
  std::string code="{ tr -cd '[:alnum:]' </dev/urandom | head -c $1; }";
  function* fct=parse_function(code.c_str(), code.size(), 0).first;
  fct->name="__lxsh_random";
  return fct;
}

bool r_debashify(_obj* o, bool* need_random_func)
{
  switch(o->type)
  {
    case _obj::_list: {
      list* t = dynamic_cast<list*>(o);
      if(debashify_procsub(t))
        *need_random_func = true;
    } break;
    case _obj::block_cmd: {
      cmd* t = dynamic_cast<cmd*>(o);
      debashify_combined_redirects(t);
      debashify_bashtest(t);
      debashify_declare(t);
      debashify_array_def(t);
    } break;
    case _obj::block_subshell: {
      subshell* t = dynamic_cast<subshell*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_brace: {
      brace* t = dynamic_cast<brace*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_main: {
      shmain* t = dynamic_cast<shmain*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_function: {
      function* t = dynamic_cast<function*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_case: {
      case_block* t = dynamic_cast<case_block*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_if: {
      if_block* t = dynamic_cast<if_block*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_while: {
      while_block* t = dynamic_cast<while_block*>(o);
      debashify_combined_redirects(t);
    } break;
    case _obj::block_for: {
      for_block* t = dynamic_cast<for_block*>(o);
      debashify_combined_redirects(t);
    } break;
    default: break;
  }
  return true;
}

void debashify(shmain* sh)
{
  bool need_random_func=false;
  sh->shebang = "#!/bin/sh";
  recurse(r_debashify, sh, &need_random_func);
  if(need_random_func)
    sh->lst->insert(0, new condlist(create_random_func()));
}