Is it possible to call "updateauth" to change account keys from within a smart contract?

Question

I am trying to write a smart contract that changes the keys of an account (not itself). The transaction will be of course be authorized by the account for which the keys are changing.

I feel like it should look something like this:

action(N(eosio), 
        N(updateauth), 
        N(eosbayitem), 
        fc::mutable_variant_object()
       ("account", "myaccount")
       ("permission", "owner")
       ("parent", "")
       ("auth",  authority("EOS8djkstZzKVY7BsWkT3CMQjngXMSgtoM2g3VAS65wZw1JLC4fML", 1)).send();

Answer 1

Yes, it is possible.

The action is in native.hpp in the eosio.system contract from eosio.cdt repository:

     [[eosio::action]]
     void updateauth(  ignore<name>  account,
                       ignore<name>  permission,
                       ignore<name>  parent,
                       ignore<authority> auth ) {}

You would use it like this:

struct authority {
  uint32_t                                           threshold = 0;
  std::vector<eosiosystem::key_weight>               keys;
  std::vector<eosiosystem::permission_level_weight>  accounts;
  std::vector<eosiosystem::wait_weight>              waits;

  EOSLIB_SERIALIZE( authority, (threshold)(keys)(accounts)(waits) )
};

// Create the authority type for auth argument of updateauth action
authority newauth;
newauth.threshold = threshold;
eosio::permission_level permission(eosio::name("account_name"), eosio::name("account_permission"));
eosiosystem::permission_level_weight accountpermission{permission, weight};
newauth.accounts.emplace_back(accountpermission);

// Send off the action to updateauth
eosio::action(eosio::permission_level(get_self(), eosio::name("active")), eosio::name("eosio"), eosio::name("updateauth"), std::tuple(eosio::name("account_name"), eosio::name("permission_name"), eosio::name("parent_name"), newauth) ).send();