/*
 * Copyright (c) 2019-2024, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */

#include "tf_fuzz.hpp"

#include <ext/alloc_traits.h>
#include <ctime>  // to seed random, if seed not passed in
#include <string>
#include <vector>
#include <iostream>
#include <fstream>

#include "boilerplate.hpp"
#include "string_ops.hpp"
#include "data_blocks.hpp"
#include "psa_asset.hpp"
#include "find_or_create_asset.hpp"
#include "sst_asset.hpp"
#include "crypto_asset.hpp"
#include "psa_call.hpp"
#include "tf_fuzz_grammar.tab.hpp"
#include "variables.hpp"
#include "crypto_model.hpp"


extern FILE* yyin;  // telling lex&yacc which file to parse

using namespace std;

long psa_asset::unique_id_counter = 10;  // counts unique IDs for assets
long psa_call::unique_id_counter = 10;  // counts unique IDs for assets
    /* FYI:  Must initialize these class variables outside the class.  If
             initialized inside the class, g++ requires they be const. */

/**********************************************************************************
   Methods of class tf_fuzz_info follow:
**********************************************************************************/

asset_search tf_fuzz_info::find_or_create_sst_asset (
    psa_asset_search criterion,  // what to search on
    psa_asset_usage where,  // where to search
    string target_name,  // ignored if not searching on name
    uint64_t target_id,  // also ignored if not searching on ID (e.g., SST UID)
    long &serial_no,  // search by asset's unique serial number
    bool create_asset,  // true to create the asset if it doesn't exist
    vector<psa_asset*>::iterator &asset  // returns a pointer to requested asset
) {
    return generic_find_or_create_asset<sst_asset>(
               active_sst_asset, deleted_sst_asset,
               invalid_sst_asset, criterion, where, target_name, target_id,
               serial_no, create_asset, asset
           );
}

asset_search tf_fuzz_info::find_or_create_key_asset (
    psa_asset_search criterion,  // what to search on
    psa_asset_usage where,  // where to search
    string target_name,  // ignored if not searching on name
    uint64_t target_id,  // also ignored if not searching on ID (e.g., SST UID)
    long &serial_no,  // search by asset's unique serial number
    bool create_asset,  // true to create the asset if it doesn't exist
    vector<psa_asset*>:: iterator &asset  // returns iterator to requested asset
) {
    return generic_find_or_create_asset<key_asset>(
               active_key_asset, deleted_key_asset,
               invalid_key_asset, criterion, where, target_name, target_id,
               serial_no, create_asset, asset
           );
}

asset_search tf_fuzz_info::find_or_create_policy_asset (
    psa_asset_search criterion,  // what to search on
    psa_asset_usage where,  // where to search
    string target_name,  // ignored unless searching on name
    uint64_t target_id,  // also ignored unless searching on ID (e.g., SST UID)
    long &serial_no,  // search by asset's unique serial number
    bool create_asset,  // true to create the asset if it doesn't exist
    vector<psa_asset*>::iterator &asset  // iterator to requested asset
) {
    return generic_find_or_create_asset<policy_asset>(
               active_policy_asset, deleted_policy_asset,
               invalid_policy_asset, criterion, where, target_name, target_id,
               serial_no, create_asset, asset
           );
}

asset_search tf_fuzz_info::find_or_create_psa_asset (
    psa_asset_type asset_type,  // what type of asset to find
    psa_asset_search criterion,  // what to search on
    psa_asset_usage where,  // where to search
    string target_name,  // ignored if not searching on name
    uint64_t target_id,  // also ignored if not searching on ID (e.g., SST UID)
    long &serial_no,  // search by asset's unique serial number
    bool create_asset,  // true to create the asset if it doesn't exist
    vector<psa_asset*>::iterator &asset  // returns iterator to asset
) {
    switch (asset_type) {
        case psa_asset_type::sst:
            return find_or_create_sst_asset (
                criterion, where, target_name, target_id,
                serial_no, create_asset, asset);
            break;
        case psa_asset_type::key:
            return find_or_create_key_asset (
                criterion, where, target_name, target_id,
                serial_no, create_asset, asset);
            break;
        case psa_asset_type::policy:
            return find_or_create_policy_asset (
                criterion, where, target_name, target_id,
                serial_no, create_asset, asset);
            break;
        default:
            cerr << "\nError:  Internal:  Please report error "
                 << "#1503 to TF-Fuzz developers." << endl;
            exit (1500);
    }
}

// Return an iterator to a variable, if it exists.  If not return variable.end().
vector<variable_info>::iterator tf_fuzz_info::find_var (string var_name)
{
    vector<variable_info>::iterator the_var;
    if (variable.empty()) {
        return variable.end();
    }
    for (the_var = variable.begin();  the_var < variable.end();  the_var++) {
        if (the_var->name == var_name) {
            break;
        }
    }
    return the_var;
}
// Add a variable to the vector if not already there; return true if already there.
bool tf_fuzz_info::make_var (string var_name)
{
    bool found = false;
    variable_info new_variable;

    found = (find_var (var_name) != variable.end());
    if (!found) {
        new_variable.name.assign (var_name);
        variable.push_back (new_variable);
    }
    return found;
}


// Remove any PSA resources used in the test.  Returns success==true, fail==false.
void tf_fuzz_info::teardown_test (void)
{
    string call;
    // Traverse through the SST-assets list, writing out remove commands:
    for (auto &asset : active_sst_asset) {
      //  write once assets cannot be removed

      //  NOTE: As write once assets persist across tests, there is as
      //  chance of UID collisions between tests. There is no technical solution
      //  for this - test authors just have to be careful in their use of
      //  WRITE_ONCE.
      if (asset->set_data.flags_string.find("PSA_STORAGE_FLAG_WRITE_ONCE") !=
          std::string::npos) {
            continue;
      }
        call = bplate->bplate_string[teardown_sst];
        find_replace_1st ("$uid", to_string(asset->asset_info.id_n), call);
        call.append (bplate->bplate_string[teardown_sst_check]);
        output_C_file << call;
    }
    // Same, but with key assets:
    for (auto &asset : active_key_asset) {
        call = bplate->bplate_string[teardown_key];
        find_replace_1st ("$handle", asset->handle_str, call);
        call.append (bplate->bplate_string[teardown_key_check]);
        output_C_file << call;
    }
}

// Write out the test itself.
void tf_fuzz_info::write_test (void)
{
    string call;
    string work = bplate->bplate_string[preamble_A];  // a temporary workspace string

    // The test file should be open before calling this method.
    // Spit out the obligatory preamble:
    find_replace_all ("$purpose", test_purpose, work);
    output_C_file << work;

    // If using hashing, then spit out the hashing functions:
    if (include_hashing_code) {
        work = bplate->bplate_string[hashing_code];
        output_C_file << work;
    }

    // Print out the second part of the preamble code:
    work = bplate->bplate_string[preamble_B];
    find_replace_all ("$purpose", test_purpose, work);
    output_C_file << work;

    output_C_file << "    /* Variables (etc.) to initialize and check PSA "
                  << "assets: */" << endl;
    for (auto call : calls) {
        // Reminder:  calls is a vector of *pointers to* psa_call subclass objects.
        call->fill_in_prep_code();
        call->write_out_prep_code (output_C_file);
    }

    // Print out the final part of the preamble code:
    work = bplate->bplate_string[preamble_C];
    find_replace_all ("$purpose", test_purpose, work);
    output_C_file << work;

    output_C_file << "\n\n    /* PSA calls to test: */" << endl;
    for (auto call : calls) {
        call->fill_in_command();  // (fills in check code too)
        call->write_out_command (output_C_file);
        call->write_out_check_code (output_C_file);
    }

    output_C_file << "\n\n    /* Removing assets left over from testing: */"
                  << endl;
    teardown_test();

    // Seal the deal:
    output_C_file << bplate->bplate_string[closeout];

    // Close the template and test files:
    output_C_file.close();
    fclose (template_file);
}


/* simulate_calls() goes through the vector of generated calls calculating expected
   results for each. */
void tf_fuzz_info::simulate_calls (void){
    bool asset_state_changed = false;

    IV(cout << "Call sequence:" << endl;);

    /* The thinking logic will probably need elaborating in the future.
     *
     * The current algorithm goes through the calls, simuating their expected
     * return codes. After call simulation, assets are updated, which are then
     * allowed to react to the new information. Asset simulation loops until they
     * all agree that they're "quiescent". Finally, result information is copied
     * from the asset back to the call.
     */
    for (auto this_call : calls) {
        IV(cout << "    " << this_call->call_description << " for asset "
                << this_call->asset_info.get_name() << endl;)

        this_call->copy_policy_to_call();
        this_call->simulate();
        this_call->copy_call_to_asset();
           /* Note:  this_call->the_asset will now point to the asset
                     associated with this_call, if any such asset exists. */
    if (this_call->asset_info.the_asset != nullptr) {
      /* If the asset exists, allow changes to it to affect other active
         assets. */
      asset_state_changed = false;
      do {
        for (auto this_asset : active_sst_asset) {
          asset_state_changed |= this_asset->simulate();
        }
        for (auto this_asset : active_policy_asset) {
          asset_state_changed |= this_asset->simulate();
        }
        for (auto this_asset : active_key_asset) {
          asset_state_changed |= this_asset->simulate();
        }
      } while (asset_state_changed);
        }
        this_call->copy_asset_to_call();
    }
}


/* Parse command-line parameters.  exit() if error(s) found.  Place results into
   the resource object. */
void tf_fuzz_info::parse_cmd_line_params (int argc, char* argv[])
{
    int exit_val = 0;  // the linux return value, default 0, meaning all-good
    vector<string> cmd_line_parameter, cmd_line_switch;
        // (STL) vectors of hard cmd_line_parameter and cmd_line_switches
    int n_parameters = 0, n_switches = 0;
        // counting off cmd_line_parameter and cmd_line_switches while parsing
    char testc;

    // Parse arguments into lists of strings:
    for (int i = 1;  i < argc;  ++i) {
        if (argv[i][0] == '-') {  // cmd_line_switch
            if (argv[i][1] == '-') {  // double-dash
                cmd_line_switch.push_back (string(argv[i]+2));
            } else {  // single-dash cmd_line_switch;  fine either way
                cmd_line_switch.push_back (string(argv[i]+1));
            }
            ++n_switches;
        } else {  // hard cmd_line_parameter
            cmd_line_parameter.push_back(argv[i]);
            ++n_parameters;
        }
    }
    // If too-few or too many cmd_line_parameter supplied
    for (int i = 0;  i < n_switches;  ++i) {
        // If usage string requested...
        if (cmd_line_switch[i] == "h") {
            exit_val = 10;
        }
        // If verbose requested, make note:
        if (cmd_line_switch[i] == "v") {
            verbose_mode = true;
        }
    }
    if (exit_val == 10) {  // -h switch
        cout << "\nHow to run TF-Fuzz:" << endl;
    } else if (n_parameters < 2) {
        cerr << "\nToo few command-line parameters." << endl;
        exit_val = 11;
    } else if (n_parameters > 3) {
        cerr << "\nToo many command-line parameters." << endl;
        exit_val = 12;
    } else {
        template_file_name = cmd_line_parameter[0];
        template_file = fopen (template_file_name.c_str(), "r");
        test_output_file_name = cmd_line_parameter[1];
        output_C_file.open (test_output_file_name, ios::out);
        if (n_parameters == 3) {
            /* TODO:  The try-catch below doesn't always seem to work.  For now,
               manually "catch" the most basic problem: */
            testc = cmd_line_parameter[2][0];
            if (testc < '0' || testc > '9') {
                cerr << "\nError:  Random-seed value (third parameter) could "
                     << "not be interpreted as a number." << endl;
                rand_seed = 0;
            } else {
                try {
                    rand_seed = stol (cmd_line_parameter[2], 0, 0);
                } catch (int excep) {
                    excep = 0;  // (keep compiler from complaining about not using excep)
                    cerr << "\nWarning:  Random-seed value (third parameter) could "
                         << "not be interpreted as a number." << endl;
                    rand_seed = 0;
                }
            }
        }
        if (rand_seed == 0 || n_parameters < 3) {
            if (n_parameters < 3) {
                cout << "Info:  random seed was not specified." << endl;
            } else {
                cout << "Warning:  random seed, " << cmd_line_parameter[2]
                     << ", was not usable!" << endl;
            }
            srand((unsigned int) time(0));  // TODO:  ideally, XOR or add in PID#
            rand_seed = rand();
                /* doesn't really matter, but it just "feels better" when the
                   default seed value is itself more random. */
        }
        cout << endl << "Using seed value of " << dec << rand_seed << " " << hex
             << "(0x" << rand_seed << ")." << endl;
        srand(rand_seed);
        if (template_file == NULL) {
            cerr << "\nError:  Template file " << template_file_name
                 << " could not be opened." << endl;
            exit_val = 13;
        } else if (!output_C_file.is_open()) {
            // If test-output file couldn't be opened
            cerr << "\nError:  Output C test file " << test_output_file_name
                 << " could not be opened." << endl;
            exit_val = 14;
        }
        // Default (not entirely worthless) purpose of the test:
        test_purpose.assign (  "template = " + template_file_name + ", seed = "
                             + to_string(rand_seed));
    }
    // Bad command line, or request for usage blurb, so tell them how to run us:
    if (exit_val != 0) {
        cout << endl << argv[0] << " usage:" << endl;
        cout << "    Basic cmd_line_parameter (positional, in order, "
             << "left-to-right):" << endl;
        cout << "        Test-template file" << endl;
        cout << "        Test-output .c file" << endl;
        cout << "        (optional) random seed value" << endl;
        cout << "    Optional switches:" << endl;
        cout << "        -h or --h:  This help (command-line usage) summary."
             << endl;
        cout << "        -v or --v:  Verbose mode." << endl;
        cout << "Examples:" << endl;
        cout << "    " << argv[0] << " -h" << endl;
        cout << "    " << argv[0] << " template.txt output_test.c 0x5EED" << endl;
        exit (exit_val);
    }
}


void tf_fuzz_info::add_call (psa_call *the_call, bool append_bool,
                             bool set_barrier_bool) {
    // For testing purposes only, uncomment this to force sequential ordering:
    //append_bool = true;
    vector<psa_call*>::size_type
        barrier_pos = 0,
            // barrier pos. before which calls for this asset may not be placed
        insert_call_pos = 0,  // where to place the new call
        i;  // loop index
    bool barrier_found = false;
    psa_call *candidate = nullptr;  // (not for long)

    if (set_barrier_bool) {
        // Prevent calls regarding this asset being placed before this call:
        the_call->barrier.assign (the_call->target_barrier);
        IV(cout << "Inserted barrier for asset " << the_call->barrier << "." << endl;)
    }
    if (append_bool || calls.size() == 0) {
        // Just .push_back() onto the end if asked to, or if this is the first call:
        calls.push_back (the_call);
        IV(cout << "Appended to end of call sequence:  " << the_call->call_description
                 << "." << endl;)
        return;  // done, easy!
    }
    /* Now search for last call with a barrier for this asset.  (Note:  because
       vector<psa_call*>::size_type is unsigned, we can't search backward from
       .end(), decrementing past 0.  Also, cannot initialize barrier_pos to -1;
       must maintain boolean for that.) */
    for (i = 0ULL, barrier_found = false;  i < calls.size();  i++) {
        candidate = calls[i];
        if (candidate->barrier == the_call->target_barrier) {
            barrier_pos = i;
            barrier_found = true;
        }
    }
    if (!barrier_found) {
        /* STL-vector inserts occur *before* the stated index.  With no barrier
           found, we want to insert somewhere between before .begin() and after
           .end().  So, we want a number between 0 and calls.size(), inclusive. */
        insert_call_pos = (rand() % (calls.size() + 1));
        IV(cout << "No barrier for asset " << the_call->asset_info.get_name()
                 << " found." << endl
                 << "    Placing " << the_call->call_description
                 << " at position " << insert_call_pos << " in call sequence."
                 << endl;)
    } else {
        /* Insert at a random point between just after barrier and after the end
           (including possibly after the end, but strictly after that barrier).
           Since STL-vector inserts occur before the stated index, we want an
           insertion point between the call after the barrier and calls.end(),
           inclusive. */
        insert_call_pos = (vector<psa_call*>::size_type)
                          (   barrier_pos + 1  // must be *after* barrier-carrying call
                           + (rand() % (calls.size() - barrier_pos))
                          );
        IV(cout << "Barrier for asset " << the_call->asset_info.get_name()
                 << " found at position " << dec << barrier_pos << "." << endl;)
    }
    if (insert_call_pos == calls.size()) {
        // Insert at end:
        calls.push_back (the_call);
        IV(cout << "Insertion position is at end of call list." << endl;)
    } else {
        // Insert before insert_call_position:
        calls.insert (calls.begin() + insert_call_pos, the_call);
        IV(cout << "Inserting " << the_call->call_description
                 << " at position " << dec << insert_call_pos << " in call sequence."
                 << endl;)
    }
}


tf_fuzz_info::tf_fuzz_info (void)  // (constructor)
{
    this->bplate = new boilerplate();
    test_purpose = template_file_name = test_output_file_name = "";
    rand_seed = 0;
    verbose_mode = false;
    include_hashing_code = false;  // default
}

tf_fuzz_info::~tf_fuzz_info (void)
{
    delete bplate;
}

/**********************************************************************************
   End of methods of class tf_fuzz_info.
**********************************************************************************/


int main(int argc, char* argv[])
{
    cout << "Trusted Firmware Fuzzer (TF-Fuzz) starting..." << endl << endl;

    // Allocate "the world":
    tf_fuzz_info *rsrc = new tf_fuzz_info;

    crypto_model::init_crypto_model();

    // Parse parameters and open files:
    rsrc->parse_cmd_line_params (argc, argv);

    // Parse the test-template file:
    yyin = rsrc->template_file;
    int parse_result = yyparse (rsrc);

    if (parse_result == 1) {
        cerr << "\nError:  Template file has errors." << endl;
    } else if (parse_result == 2) {
        cerr << "\nError:  Sorry, TF-Fuzz ran out of memory." << endl;
    }
    cout << "Call sequence generated." << endl;

    cout << "Simulating call sequence..." << endl;
    rsrc->simulate_calls();

    cout << "Writing test file, " << rsrc->test_output_file_name << "." << endl;
    rsrc->write_test();
    rsrc->output_C_file.close();

    cout << endl << "TF-Fuzz test generation complete." << endl;
    return 0;
}