scpitester.c

/* Compile with -DUSE_READLINE and -lreadline to use readline for input. */

#include <arpa/inet.h>
#include <errno.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

#ifdef USE_READLINE
#include <readline/history.h>
#include <readline/readline.h>
#endif /* USE_READLINE */

#define NETBFRLEN 1024

int clientsocket;

void closeclient() {
  if (clientsocket != -1 && clientsocket != 0) {
    // shutdown(clientsocket, SHUT_WR);
    // shutdown(clientsocket, SHUT_RD);
    close(clientsocket);
  }
}

void sighandler(int s) {
  closeclient();
  _exit(0);
}

int main(int argc, char** argv) {
  if (argc == 1) {
    fprintf(stderr, "Please supply address and port\n");
    return 1;
  }

  struct sigaction sigint_handler;
  sigint_handler.sa_handler = sighandler;
  sigemptyset(&sigint_handler.sa_mask);
  sigint_handler.sa_flags = 0;
  sigaction(SIGINT, &sigint_handler, NULL);

  char inbuffer[NETBFRLEN] = {0};
  struct sockaddr_in server_addr;
  socklen_t addr_size;

  if ((clientsocket = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
    perror("socket");
    return 1;
  }

  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(atoi(argv[2]));
  server_addr.sin_addr.s_addr = inet_addr(argv[1]);
  memset(server_addr.sin_zero, 0, sizeof(server_addr.sin_zero));

  addr_size = sizeof(server_addr);
#if 0
  if (connect(clientsocket, (struct sockaddr*)&serverAddr, addr_size) == -1) {
    perror("connect");
    return 1;
  }
#endif

#ifndef USE_READLINE
  char input[256] = {0};
#else
  char* input;
#endif /* USE_READLINE */
  ssize_t outbytes, inbytes;
  int status;

  struct pollfd pfd;
  pfd.events = POLLIN;
  pfd.fd = clientsocket;

  puts("Enter SCPI commands here.\n"
       "Queries will timeout after 1 second.\n"
       "Type 'quit', 'exit', or Control-C to quit.");

#ifdef USE_READLINE
  puts("Readline line editing features are supported.");
#endif /* USE_READLINE */

  while (1) {
#ifndef USE_READLINE
    printf("> ");
    scanf(" %253[^\n]", input);
#else
    input = readline("> ");
    if (!input) {
      closeclient();
      return 0;
    }
#endif /* USE_READLINE */

    if (0 == strcmp(input, "quit") || 0 == strcmp(input, "exit")) {
      closeclient();
      return 0;
    }

#ifdef USE_READLINE
    add_history(input);
#endif /* USE_READLINE */

    size_t l = strlen(input);
#ifdef USE_READLINE
    input = realloc(input, l + 3);
    if (!input) {
      perror("realloc");
      closeclient();
      return 1;
    }
#endif /* USE_READLINE */

    strcpy(input + l, "\r\n");

    // outbytes = write(clientsocket, input, strlen(input));
    outbytes = sendto(clientsocket, input, strlen(input), 0,
                      (struct sockaddr*)&server_addr, addr_size);
    if (outbytes == -1) {
      perror("write");
      closeclient();
      return 1;
    }

    if (NULL != strchr(input, '?')) {
      status = poll(&pfd, 1, 1000);
      if (status == 0) {
        printf("No response from server within 1 second!\n");
      } else if (status == -1) {
        perror("poll");
        closeclient();
        return 1;
      } else {
        inbytes = read(clientsocket, inbuffer, NETBFRLEN);
        if (inbytes == -1) {
          perror("read");
          closeclient();
          return 1;
        }

        printf("%s", inbuffer);
        memset(inbuffer, 0, NETBFRLEN);
      }
    }

#ifdef USE_READLINE
    free(input);
#endif /* USE_READLINE */
  }

  return 0;
}