Read card ID (IDm) by Pasori reader and send it by socket communication

felica_dump.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#include "config.h"
#include "libpafe.h"

#define RAW_ID_SIZE 8
#define ID_SIZE RAW_ID_SIZE*2

void error(const char *msg)
{
    perror(msg);
    exit(0);
}

char * mydump(uint8 * p)
{
  int i;
  char * id = (char *)malloc(ID_SIZE*sizeof(char));
  for (i = 0; i != RAW_ID_SIZE; i++) {
    sprintf(id+i*2,"%02X", p[i]);
  }
  return id;
}

int main(int argc, char ** argv)
{
  pasori * p;
  char * last_id = (char *)malloc(ID_SIZE*sizeof(char));
  char * current_id, * man_id;
  p = pasori_open();
  if (!p) {
    printf("error\n");
    exit(-1);
  }

  /*  Socket section */
  int sockfd, portno, n;
  struct sockaddr_in serv_addr;
  struct hostent *server;
  if (argc < 3) {
      fprintf(stderr,"Usage: %s hostname port\n", argv[0]);
      exit(0);
  }
  /* Socket section end */

  for(;;) {
    felica * f;
    pasori_init(p);
    f = felica_polling(p, FELICA_POLLING_ANY, 0, 0);
    if (!f) continue;

    current_id = (char *)mydump(f->IDm);
    man_id = (char *)mydump(f->PMm);
    // Iff haven't read this, sleep 1 sec
    if(strncmp(last_id, current_id, ID_SIZE)!=0) sleep(1);
    // printf("%s: %s\n\a", current_id, man_id);
    printf("%s\n", current_id);

    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
      fprintf(stderr,"ERROR, no such host\n");
      exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr,
    (char *)&serv_addr.sin_addr.s_addr,
    server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) {
          fprintf(stderr,"ERROR connecting, retrying in 2 seconds...\n");
          sleep(2);
          continue;
    }
    n = write(sockfd,current_id,strlen(current_id));
    if (n < 0) error("ERROR writing to socket");
    strcpy(last_id, current_id);

    close(sockfd);
    free(f);
    sleep(5);
  }
  pasori_close(p);
  return 0;
}