Related
I am working on a school project. I have to build a robot that will push the other robot off the table.
the robot should have a camera and move by it self, but my teacher said that if i manage to connect xbox controller to it it will be fine.
I was given an esp8266 NodeMCU v3, Arduino uno, 2 motors, l298n motor driver and nothing else.
I have writen a code in python and ArduinoIDE
void setup()
{
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(12, OUTPUT);
pinMode(14, OUTPUT);
Serial.begin(9600);
}
void rr(int value1, int value2)
{
analogWrite(4, value1);
analogWrite(5, value2);
}
void rl(int value1, int value2)
{
analogWrite(12, value1);
analogWrite(14, value2);
}
void loop()
{
String read = Serial.readString();
int power = read.toInt();
rr(power, 0);
rl(power, 0);
}
import pygame, sys, serial
import time
time.sleep(1.0)
ser = serial.Serial("COM5", 9600)
pygame.joystick.init()
joystick = [pygame.joystick.Joystick(x) for x in range(pygame.joystick.get_count())]
pygame.init()
clock = pygame.time.Clock()
def map_range(x, a, b, c, d):
y = (x-a) * (d-c) / (b-a) + c
return y
while True:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
position = round(pygame.joystick.Joystick(0).get_axis(5))
#position = 100
ser.write(str(map_range(position, -1, 1, 0, 255)).encode("utf-8"))
I wonder if it possible to wirelessly update "power" variable so i can controll the robot speed.
I have done lots of reserch and i was not able to find anything that will work
Why the interpreter complains that library named "math" does not exist?
As far as I know, this library is loaded when invoking luaL_newstate on Lua-5.3.5.
#include "lua.hpp"
#include <iostream>
#include <assert.h>
#include <fstream>
int main()
{
struct lua_State *L = luaL_newstate();
int ret;
std::string fileName("co.lua");
if(fileName.empty())
{
std::cout << "the filename is empty" << std::endl;
return -1;
}
std::ifstream fileScript(fileName, fileScript.in|std::ios::ate);
if(!fileScript.is_open())
{
std::cout << "open file failed" << std::endl;
return -2;
}
size_t size = fileScript.tellg();
if(size <= 0)
{
std::cout << "file has no valid content" << std::endl;
return -3;
}
std::string textCont(size, '\0');
fileScript.seekg(0);
fileScript.read(&textCont[0], size);
if((ret=luaL_loadbuffer(L, textCont.data(), textCont.length(), "co.lua")) == LUA_OK)
{
if((ret=lua_pcall(L, 0, LUA_MULTRET, 0)) != LUA_OK)
{
std::cout << "error in invoking lua_pcall():" << ret << std::endl;
if(lua_isstring(L, -1))
{
const char *errMsg = lua_tostring(L, -1);
lua_pop(L, 1);
std::cout << "script run encounter err:" << errMsg << std::endl;
}
}
}
}
Here is the code snippet(it's very simple) for the file named "co.lua":
a = 1;
b=2;
a=a+1;
math.sin(a)
Here is the error message in the console:
error in invoking lua_pcall():2
script run encounter err:[string "co.lua"]:29: attempt to index a nil value (global 'math')
The documentation states that you need to call luaL_openlibs or luaL_requiref which does not seem to be the case with your posted program.
To have access to these libraries, the C host program should call the luaL_openlibs function, which opens all standard libraries.
Alternatively (emphasis mine):
Alternatively, the host program can open them individually by using luaL_requiref to call:
luaopen_base (for the basic library)
luaopen_package (for the package library)
luaopen_coroutine (for the coroutine library)
luaopen_string (for the string library)
luaopen_utf8 (for the UTF8 library)
luaopen_table (for the table library)
luaopen_math (for the mathematical library)
luaopen_io (for the I/O library)
luaopen_os (for the operating system library)
luaopen_debug (for the debug library).
These functions are declared in lualib.h.
So change your program's first few lines to something like below.
You also need to compare the return value from luaL_newstate with NULL and handle that error condition.
int main()
{
struct lua_State *L = luaL_newstate();
if( L == NULL ) {
puts( "Lua failed to initialize." );
exit(1);
}
luaL_openlibs( L );
// etc
I am trying to make a child class of LeafSystem whose output is sinusoidal and its derivative.
I wrote the code and try to plot it but signal logger doesn't log correctly.
#include "drake/systems/framework/leaf_system.h"
#include "drake/systems/analysis/simulator.h"
#include "drake/systems/framework/diagram.h"
#include "drake/systems/framework/diagram_builder.h"
#include "drake/systems/primitives/signal_logger.h"
#include "drake/common/proto/call_python.h"
class Sinusoid : public drake::systems::LeafSystem<double>
{
public:
Sinusoid (double tstart, double freq, double amp, double offset) :
m_freq(freq), m_amp(amp), m_offset(offset), m_tstart(tstart) {
this->DeclareVectorOutputPort(
drake::systems::BasicVector<double>(2), &Sinusoid::output);
}
private:
void output(const drake::systems::Context<double>& c, drake::systems::BasicVector<double>* output) const {
double t(c.get_time());
double tknot(t - m_tstart);
if (t > m_tstart) {
output->SetAtIndex(0, std::sin(tknot*m_freq + m_offset)*m_amp);
output->SetAtIndex(1, std::cos(tknot*m_freq + m_offset)*m_amp*m_freq);
} else {
output->SetAtIndex(0, 0.0);
output->SetAtIndex(1, 0.0);
}
}
double m_freq{0.0}, m_amp{0.0}, m_offset{0.0}, m_tstart{0.0};
};
int main(int argc, char *argv[])
{
// Add System and Connect
drake::systems::DiagramBuilder<double> builder;
auto system = builder.AddSystem<Sinusoid>(1.0, 2.*M_PI*1., 3., 0.);
auto logger = LogOutput(system->get_output_port(0), &builder);
auto diagram = builder.Build();
// Construct Simulator
drake::systems::Simulator<double> simulator(*diagram);
// Run simulation
simulator.StepTo(100);
// Plot with Python
auto sample_time = logger->sample_times();
auto sample_data = logger->data();
std::cout << sample_time.size() << std::endl;
for (int i = 0; i < sample_time.size(); ++i) {
std::cout << sample_time(i) << " : " << sample_data(i, 0) << " " << sample_data(i, 1) << std::endl;
}
std::cout << "END" << std::endl;
return 0;
}
The output of the code is
2
0 : 0 0
0 : 0 0
END
Whatever number I used in StepTo function, signal logger only cate 2 data whose sampled times are both 0.
The code looks good. Note that TrajectorySource does this almost exactly (and used SingleOutputVectorSource as a base class, which you might consider, too). The only problem is that you do not have anything telling the simulator that there is a reason to evaluate the output port. The logger block will pull on that for every publish event, but you haven't told the simulator to publish.
The solution is to call
simulator.set_publish_every_timestep(true)
http://drake.mit.edu/doxygen_cxx/classdrake_1_1systems_1_1_simulator.html#aef1dc6aeb821503379ab1dd8c6044562
If you want to further control the timestep of the integrator, you could set the parameters of the integrator (e.g. simalator.get_integerator), then calls like set_fixed_step_mode.
Context
I've got a pcap file containing a bunch of beacon frames (in other words, I put my Wi-Fi adapter in monitor mode, started capturing while filtering on "wlan.fc.type_subtype == 0x08", and saved that).
Now, I want to, somehow, display specific fields of these packets. Among others:
SSID (wlan_mgt.ssid)
MAC (wlan.ta)
Current channel (wlan_mgt.ds.current_channel)
Group Cipher (wlan_mgt.rsn.gcs.type)
PairWise Ciphers (wlan_mgt.rsn.pcs.type)
Authentication Suite (wlan_mgt.rsn.akms.type)
I don't really care about the representation: plain text, xml, json, csv, X. I'm fine with it. I just don't want more data than I really need and the output needs to be meaningful to the human (wireshark newb) eye.
Eventually, I also want to filter the pcap to get a unique set and count the occurrences (some "|sort|uniq -c" will do), but let's not go there for now.
My solution so far
The first step could be, for example:
$ tshark -r capture.pcap -c 1 -T fields -e wlan_mgt.ssid -e wlan.ta -e wlan_mgt.ds.current_channel -e wlan_mgt.rsn.gcs.type -e wlan_mgt.rsn.pcs.type -e wlan_mgt.rsn.akms.type
MySSID XX:XX:XX:XX:XX:XX 2 4 4 2
After (manually) matching the numbers to their textual meaning, you get this:
SSID = MySSID
MAC (wlan.ta) = XX:XX:XX:XX:XX:XX
Current channel = 2
Group Cipher = Group Cipher Suite type: AES (CCM) (4)
PairWise Ciphers = Pairwise Cipher Suite type: AES (CCM) (4)
Authentication Suite = Auth Key Management (AKM) type: PSK (2)
This is what I'm looking for. But, as stated, I have to do it manually, which is not an option.
Question
Above you can see my current approach to the said goal. By doing
tshark -r capture.pcap -c 1 -T pdml
I get, for example (cutout):
<field name="wlan_mgt.rsn.pcs.list" showname="Pairwise Cipher Suite List 00-0f-ac (Ieee8021) AES (CCM)" size="4" pos="112" show="" value="">
<field name="wlan_mgt.rsn.pcs" showname="Pairwise Cipher Suite: 00-0f-ac (Ieee8021) AES (CCM)" size="4" pos="112" show="1027076" value="000fac04">
<field name="wlan_mgt.rsn.pcs.oui" showname="Pairwise Cipher Suite OUI: 00-0f-ac (Ieee8021)" size="3" pos="112" show="4012" value="000fac"/>
<field name="wlan_mgt.rsn.pcs.type" showname="Pairwise Cipher Suite type: AES (CCM) (4)" size="1" pos="115" show="4" value="04"/>
</field>
</field>
..., which tells me that tshark does have the information I need (in the form of the "showname" attribute).
Apparently, when working with "-T fields -e X", tshark outputs the value that's in the "show" attribute". I feel like I want what's behind the "showname" attribute. Unfortunately, after annoying google for a while I still don't know how or if this is even possible.
I'm also open to radically different ideas, but the main takeaway is that I can't part from the pcap file (which rules out iwlist, kismet, etc). I also preferably don't start writing search and replace rules to replace the meaningless numbers with their textual representation. I hope to solve it in cleaner way.
I kept messing with tshark for a while, until I decided that it couldn't be done. A little bit of programming using the amazing C++ library libtins got me where I needed to be.
The source is down below. Enjoy :)
#include <tins/tins.h>
#include <algorithm>
#include <iostream>
#include <map>
#include <string>
using namespace Tins;
using namespace std;
/*
* Container class for the data that is retrieved from the beacon.
*/
class Unit {
public:
/*
* Constructor. Parses the Dot11Beacon object and takes all the necessary
* data from it.
*/
Unit(Dot11Beacon& beacon);
Unit() = default;
unsigned getCount();
void incrementCount();
/*
* Prints this object onto the command line, in CSV format
*/
void print();
private:
string ssid;
string bssid;
unsigned channel;
unsigned count;
string gcs; // Group Cipher Suite
string pcs; // Pairwise Cipher Suite
string akm; // Authentication suite
/*
* Returns a string representation of a RSNInformation::CypherSuites enum value
*/
string type_to_string(const RSNInformation::CypherSuites& type);
/*
* Returns a string representation of a RSNInformation::AKMSuites enum value
*/
string type_to_string(const RSNInformation::AKMSuites& type);
};
Unit::Unit(Dot11Beacon& beacon) :
count {1} /* When this unit is created, it has been seen exactly once */ {
ssid = beacon.ssid();
bssid = beacon.addr3().to_string();
channel = unsigned(beacon.ds_parameter_set());
RSNInformation rsn;
for(const auto &opt : beacon.options()) {
if (opt.option() == Dot11::RSN) {
rsn = beacon.rsn_information();
// Put all authentication suite types in a string
const RSNInformation::akm_type& akmTypeList = rsn.akm_cyphers();
for (const auto& akmIt : akmTypeList) {
if (akm.size() == 0)
akm += type_to_string(akmIt);
else
akm += ";" + type_to_string(akmIt);
}
// Put all group cipher types in a string
const RSNInformation::CypherSuites& gcsType = rsn.group_suite();
gcs = type_to_string(gcsType);
// Put all pairwise ciphers in a string
const RSNInformation::cyphers_type& pcsTypeList = rsn.pairwise_cyphers();
for (const auto& pcsIt : pcsTypeList) {
if (pcs.size() == 0)
pcs += type_to_string(pcsIt);
else
pcs += ";" + type_to_string(pcsIt);
}
}
}
}
unsigned Unit::getCount() {
return count;
}
void Unit::incrementCount() {
count += 1;
}
void Unit::print() {
string ssid_to_print;
if (ssid.length() == 0) {
ssid_to_print = "<ZERO_LENGTH>";
} else if (!isprint(ssid[0])) {
ssid_to_print = to_string(static_cast<int>(ssid[0]));
} else {
ssid_to_print = ssid;
}
if (find(ssid_to_print.begin(), ssid_to_print.end(), ',') != ssid_to_print.end()) {
ssid_to_print = "\"" + ssid_to_print + "\"";
}
cout << ssid_to_print << ","
<< bssid << ","
<< to_string(channel) << ","
<< to_string(count) << ","
<< gcs << ","
<< pcs << ","
<< akm << endl;
}
string Unit::type_to_string(const RSNInformation::CypherSuites& type) {
switch (type) {
case RSNInformation::CypherSuites::CCMP:
return "CCMP";
break;
case RSNInformation::CypherSuites::TKIP:
return "TKIP";
break;
case RSNInformation::CypherSuites::WEP_104:
return "WEP_104";
break;
case RSNInformation::CypherSuites::WEP_40:
return "WEP_40";
break;
}
}
string Unit::type_to_string(const RSNInformation::AKMSuites& type) {
switch (type) {
case RSNInformation::AKMSuites::PMKSA:
return "PMKSA";
break;
case RSNInformation::AKMSuites::PSK:
return "PSK";
break;
}
}
/*
* Class that reads the pcap, keeps track of the units and writes out one
* beacon frame in pcap format for each unique AP it finds. This file is called
* "unique_beacons.pcap"
*/
class PCAPParser {
public:
/*
* Constructor. It takes the exact parameters that it will pas on to its
* FileSniffer object (a FileSniffer is actually just a file reader).
*/
PCAPParser(const string& pcapFilename, const string& filter);
/*
* Start reading the file.
*/
bool run();
/*
* Print CSV header and ask all of our collected Unit objects to print themselves
*/
void print();
private:
FileSniffer sniffer;
PacketWriter writer;
map<string, Unit> apMap; // stands for Access Point Map
bool handler(PDU&);
};
PCAPParser::PCAPParser(const string& pcapFilename, const string& filter) :
sniffer {pcapFilename, filter},
writer {"unique_beacons.pcap", PacketWriter::RADIOTAP} {
for (auto it = apMap.begin(); it != apMap.end(); it++) {
it->second.print();
}
}
bool PCAPParser::run() {
sniffer.sniff_loop( [this] (PDU& pdu) { return (bool) this->handler (pdu); } );
return true;
}
bool PCAPParser::handler(PDU& pdu) {
Dot11Beacon& beacon = pdu.rfind_pdu<Dot11Beacon>();
// An ESSID may span multiple BSSID's. Also, it's nice to keep track of what
// channels an AP has been on. Therefore, the combination of SSID, BSSID and
// channel is considered key.
const string& ssid = beacon.ssid();
const string& mac = beacon.addr3().to_string();
const unsigned channel = unsigned(beacon.ds_parameter_set());
const string key = ssid + mac + to_string(channel);
if (apMap.find(key) == apMap.end()) { // we've got a new one
Unit unit(beacon);
apMap[key] = unit;
writer.write(pdu);
} else {
apMap[key].incrementCount();
}
return true;
}
void PCAPParser::print() {
// Print the headers for the CSV output
cout << "SSID,BSSID,Current_channel,Count,Group_Cipher,Pairwise_Ciphers,Authentication_Suite" << endl;
// Ask each of the units to print themselves for the CSV output
for (auto it = apMap.begin(); it != apMap.end(); it++) {
it->second.print();
}
}
int main(int argc, char *argv[]) {
if(argc != 2) {
std::cout << "Usage: " << *argv << " <PCAP_FILE>\n";
return 1;
}
PCAPParser pcapParser(argv[1], "wlan type mgt subtype beacon");
pcapParser.run();
pcapParser.print();
}
Compile with:
g++ pcapreader.cpp -o pcapreader -O3 -std=c++11 -lpthread -ltins
The output is:
$ ./pcapreader capture.pcap
SSID,BSSID,Current_channel,Count,Group_Cipher, Pairwise_Ciphers,Authentication_Suite
MyWiFi,XX:XX:XX:XX:XX:XX,13,2,TKIP,TKIP;CCMP,PSK
...
...
Final note: if you open unique_beacons.pcap, you may find a lot of [Malformed Packet]. Apparently, a frame can still be successfully parsed if some of the tagged parameters are received wrongly. You could try to modify the code so that it only writes out frames to the pcap file that are completely intact.
tshark will print the "showname" attribute for text output only. You can control the output with a custom formatted by setting the gui.column.format preference. To print just SSID columns:
$ tshark -r capture.pcap -c 1 -T text -o 'gui.column.format:"SSID","%Cus:wlan.ssid"'
How do you end a long running Lua script?
I have two threads, one runs the main program and the other controls a user supplied Lua script. I need to kill the thread that's running Lua, but first I need the script to exit.
Is there a way to force a script to exit?
I have read that the suggested approach is to return a Lua exception. However, it's not garanteed that the user's script will ever call an api function ( it could be in a tight busy loop). Further, the user could prevent errors from causing his script to exit by using a pcall.
You could use setjmp and longjump, just like the Lua library does internally. That will get you out of pcalls and stuff just fine without need to continuously error, preventing the script from attempting to handle your bogus errors and still getting you out of execution. (I have no idea how well this plays with threads though.)
#include <stdio.h>
#include <setjmp.h>
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
jmp_buf place;
void hook(lua_State* L, lua_Debug *ar)
{
static int countdown = 10;
if (countdown > 0)
{
--countdown;
printf("countdown: %d!\n", countdown);
}
else
{
longjmp(place, 1);
}
}
int main(int argc, const char *argv[])
{
lua_State* L = luaL_newstate();
luaL_openlibs(L);
lua_sethook(L, hook, LUA_MASKCOUNT, 100);
if (setjmp(place) == 0)
luaL_dostring(L, "function test() pcall(test) print 'recursing' end pcall(test)");
lua_close(L);
printf("Done!");
return 0;
}
You could set a variable somewhere in your program and call it something like forceQuitLuaScript. Then, you use a hook, described here to run every n instructions. After n instructions, it'll run your hook which just checks if forceQuitLuaScript is set, and if it is do any clean up you need to do and kill the thread.
Edit: Here's a cheap example of how it could work, only this is single threaded. This is just to illustrate how you might handle pcall and such:
#include <stdlib.h>
#include "lauxlib.h"
void hook(lua_State* L, lua_Debug *ar)
{
static int countdown = 10;
if (countdown > 0)
{
--countdown;
printf("countdown: %d!\n", countdown);
}
else
{
// From now on, as soon as a line is executed, error
// keep erroring until you're script reaches the top
lua_sethook(L, hook, LUA_MASKLINE, 0);
luaL_error(L, "");
}
}
int main(int argc, const char *argv[])
{
lua_State* L = luaL_newstate();
luaL_openlibs(L);
lua_sethook(L, hook, LUA_MASKCOUNT, 100);
// Infinitely recurse into pcalls
luaL_dostring(L, "function test() pcall(test) print 'recursing' end pcall(test)");
lua_close(L);
printf("Done!");
return 0;
}
The way to end a script is to raise an error by calling error. However, if the user has called the script via pcall then this error will be caught.
It seems like you could terminate the thread externally (from your main thread) since the lua script is user supplied and you can't signal it to exit.
If that isn't an option, you could try the debug API. You could use lua_sethook to enable you to regain control assuming you have a way to gracefully terminate your thread in the hook.
I haven't found a way to cleanly kill a thread that is executing a long running lua script without relying on some intervention from the script itself. Here are some approaches I have taken in the past:
If the script is long running it is most likely in some loop. The script can check the value of some global variable on each iteration. By setting this variable from outside of the script you can then terminate the thread.
You can start the thread by using lua_resume. The script can then exit by using yield().
You could provide your own implementation of pcall that checks for a specific type of error. The script could then call error() with a custom error type that your version of pcall could watch for:
function()
local there_is_an_error = do_something()
if (there_is_an_error) then
error({code = 900, msg = "Custom error"})
end
end
possibly useless, but in the lua I use (luaplayer or PGELua), I exit with
os.exit()
or
pge.exit()
If you're using coroutines to start the threads, you could maybe use coroutine.yield() to stop it.
You might wanna take look at
https://github.com/amilamad/preemptive-task-scheduler-for-lua
project. its preemptive scheduler for lua.
It uses a lua_yeild function inside the hook. So you can suspend your lua thread. It also uses longjmp inside but its is much safer.
session:destroy();
Use this single line code on that where you are want to destroy lua script.
lua_KFunction cont(lua_State* L);
int my_yield_with_res(lua_State* L, int res) {
cout << " my_yield_with_res \n" << endl;
return lua_yieldk(L, 0, lua_yield(L, res), cont(L));/* int lua_yieldk(lua_State * L, int res, lua_KContext ctx, lua_KFunction k);
Приостанавливает выполнение сопрограммы(поток). Когда функция C вызывает lua_yieldk, работающая
сопрограмма приостанавливает свое выполнение и вызывает lua_resume, которая начинает возврат данной сопрограммы.
Параметр res - это число значений из стека, которые будут переданы в качестве результатов в lua_resume.
Когда сопрограмма снова возобновит выполнение, Lua вызовет заданную функцию продолжения k для продолжения выполнения
приостановленной C функции(смотрите §4.7). */
};
int hookFunc(lua_State* L, lua_Debug* ar) {
cout << " hookFunc \n" << endl;
return my_yield_with_res(L, 0);// хук./
};
lua_KFunction cont(lua_State* L) {// функция продолжения.
cout << " hooh off \n" << endl;
lua_sethook(L, (lua_Hook)hookFunc, LUA_MASKCOUNT, 0);// отключить хук foo.
return 0;
};
struct Func_resume {
Func_resume(lua_State* L, const char* funcrun, unsigned int Args) : m_L(L), m_funcrun(funcrun), m_Args(Args) {}
//имена функций, кол-во агрументов.
private:
void func_block(lua_State* L, const char* functionName, unsigned int Count, unsigned int m_Args) {
lua_sethook(m_L, (lua_Hook)hookFunc, LUA_MASKCOUNT, Count); //вызов функции с заданной паузой.
if (m_Args == 0) {
lua_getglobal(L, functionName);// получить имя функции.
lua_resume(L, L, m_Args);
}
if (m_Args != 0) {
int size = m_Args + 1;
lua_getglobal(L, functionName);
for (int i = 1; i < size; i++) {
lua_pushvalue(L, i);
}
lua_resume(L, L, m_Args);
}
};
public:
void Update(float dt) {
unsigned int Count = dt * 100.0;// Время работы потока.
func_block(m_L, m_funcrun, Count, m_Args);
};
~Func_resume() {}
private:
lua_State* m_L;
const char* m_funcrun; // имя функции.
unsigned int m_Count;// число итерации.
unsigned int m_Args;
};
const char* LUA = R"(
function main(y)
--print(" func main arg, a = ".. a.." y = ".. y)
for i = 1, y do
print(" func main count = ".. i)
end
end
)";
int main(int argc, char* argv[]) {
lua_State* L = luaL_newstate();/*Функция создает новое Lua состояние. */
luaL_openlibs(L);
luaL_dostring(L, LUA);
//..pushlua(L, 12);
pushlua(L, 32);
//do {
Func_resume func_resume(L, "main", 2);
func_resume.Update(1.7);
lua_close(L);
// } while (LUA_OK != lua_status(L)); // Пока поток не завершен.
return 0;
};