fsfw/hal/src/fsfw_hal/linux/CommandExecutor.cpp

#include "CommandExecutor.h"

#include <unistd.h>

#include <cstring>

#include "fsfw/container/DynamicFIFO.h"
#include "fsfw/container/SimpleRingBuffer.h"
#include "fsfw/serviceinterface.h"

CommandExecutor::CommandExecutor(const size_t maxSize) : readVec(maxSize) {
  waiter.events = POLLIN;
}

ReturnValue_t CommandExecutor::load(std::string command, bool blocking, bool printOutput) {
  if (state == States::PENDING) {
    return COMMAND_PENDING;
  }

  currentCmd = command;
  this->blocking = blocking;
  this->printOutput = printOutput;
  if (state == States::IDLE) {
    state = States::COMMAND_LOADED;
  }
  return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t CommandExecutor::execute() {
  if (state == States::IDLE) {
    return NO_COMMAND_LOADED_OR_PENDING;
  } else if (state == States::PENDING) {
    return COMMAND_PENDING;
  }
  currentCmdFile = popen(currentCmd.c_str(), "r");
  if (currentCmdFile == nullptr) {
    lastError = errno;
    return HasReturnvaluesIF::RETURN_FAILED;
  }
  if (blocking) {
    ReturnValue_t result = executeBlocking();
    state = States::IDLE;
    return result;
  } else {
    currentFd = fileno(currentCmdFile);
    waiter.fd = currentFd;
  }
  state = States::PENDING;
  return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t CommandExecutor::close() {
  if (state == States::PENDING) {
    // Attempt to close process, irrespective of if it is running or not
    if (currentCmdFile != nullptr) {
      pclose(currentCmdFile);
    }
  }
  return HasReturnvaluesIF::RETURN_OK;
}

void CommandExecutor::printLastError(std::string funcName) const {
  if (lastError != 0) {
#if FSFW_CPP_OSTREAM_ENABLED == 1
    sif::warning << funcName << " pclose failed with code " << lastError << ": "
                 << strerror(lastError) << std::endl;
#else
    sif::printError("%s pclose failed with code %d: %s\n", funcName, lastError,
                    strerror(lastError));
#endif
  }
}

void CommandExecutor::setRingBuffer(SimpleRingBuffer* ringBuffer,
                                    DynamicFIFO<uint16_t>* sizesFifo) {
  this->ringBuffer = ringBuffer;
  this->sizesFifo = sizesFifo;
}

ReturnValue_t CommandExecutor::check(bool& replyReceived) {
  if (blocking) {
    return HasReturnvaluesIF::RETURN_OK;
  }
  switch (state) {
    case (States::IDLE):
    case (States::COMMAND_LOADED): {
      return NO_COMMAND_LOADED_OR_PENDING;
    }
    case (States::PENDING): {
      break;
    }
  }

  int result = poll(&waiter, 1, 0);
  switch (result) {
    case (0): {
      return HasReturnvaluesIF::RETURN_OK;
      break;
    }
    case (1): {
      if (waiter.revents & POLLIN) {
        ssize_t readBytes = read(currentFd, readVec.data(), readVec.size());
        if (readBytes == 0) {
          // Should not happen
#if FSFW_CPP_OSTREAM_ENABLED == 1
          sif::warning << "CommandExecutor::check: No bytes read "
                          "after poll event.."
                       << std::endl;
#else
          sif::printWarning("CommandExecutor::check: No bytes read after poll event..\n");
#endif
          break;
        } else if (readBytes > 0) {
          replyReceived = true;
          if (printOutput) {
            // It is assumed the command output is line terminated
#if FSFW_CPP_OSTREAM_ENABLED == 1
            sif::info << currentCmd << " | " << readVec.data();
#else
            sif::printInfo("%s | %s", currentCmd, readVec.data());
#endif
          }
          if (ringBuffer != nullptr) {
            ringBuffer->writeData(reinterpret_cast<const uint8_t*>(readVec.data()), readBytes);
          }
          if (sizesFifo != nullptr) {
            if (not sizesFifo->full()) {
              sizesFifo->insert(readBytes);
            }
          }
        } else {
          // Should also not happen
#if FSFW_CPP_OSTREAM_ENABLED == 1
          sif::warning << "CommandExecutor::check: Error " << errno << ": " << strerror(errno)
                       << std::endl;
#else
          sif::printWarning("CommandExecutor::check: Error %d: %s\n", errno, strerror(errno));
#endif
        }
      }
      if (waiter.revents & POLLERR) {
#if FSFW_CPP_OSTREAM_ENABLED == 1
        sif::warning << "CommandExecuter::check: Poll error" << std::endl;
#else
        sif::printWarning("CommandExecuter::check: Poll error\n");
#endif
        return COMMAND_ERROR;
      }
      if (waiter.revents & POLLHUP) {
        result = pclose(currentCmdFile);
        ReturnValue_t retval = EXECUTION_FINISHED;
        if (result != 0) {
          lastError = result;
          retval = HasReturnvaluesIF::RETURN_FAILED;
        }
        state = States::IDLE;
        currentCmdFile = nullptr;
        currentFd = 0;
        return retval;
      }
      break;
    }
  }
  return HasReturnvaluesIF::RETURN_OK;
}

void CommandExecutor::reset() {
  CommandExecutor::close();
  currentCmdFile = nullptr;
  currentFd = 0;
  state = States::IDLE;
}

int CommandExecutor::getLastError() const {
  // See:
  // https://stackoverflow.com/questions/808541/any-benefit-in-using-wexitstatus-macro-in-c-over-division-by-256-on-exit-statu
  return WEXITSTATUS(this->lastError);
}

CommandExecutor::States CommandExecutor::getCurrentState() const { return state; }

ReturnValue_t CommandExecutor::executeBlocking() {
  while (fgets(readVec.data(), readVec.size(), currentCmdFile) != nullptr) {
    std::string output(readVec.data());
    if (printOutput) {
#if FSFW_CPP_OSTREAM_ENABLED == 1
      sif::info << currentCmd << " | " << output;
#else
      sif::printInfo("%s | %s", currentCmd, output);
#endif
    }
    if (ringBuffer != nullptr) {
      ringBuffer->writeData(reinterpret_cast<const uint8_t*>(output.data()), output.size());
    }
    if (sizesFifo != nullptr) {
      if (not sizesFifo->full()) {
        sizesFifo->insert(output.size());
      }
    }
  }
  int result = pclose(currentCmdFile);
  if (result != 0) {
    lastError = result;
    return HasReturnvaluesIF::RETURN_FAILED;
  }
  return HasReturnvaluesIF::RETURN_OK;
}