cnode_s.c

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include "erl_interface.h"
#include "ei.h"

#define BUFSIZE 1000

int main(int argc, char **argv) {
  int port;                      /* Listen port number */
  int listen;                    /* Listen socket */
  int fd;                        /* fd to Erlang node */
  ErlConnect conn;               /* Connection data */
  
  int loop = 1;                  /* Lopp flag */
  int got;                       /* Result of receive */
  unsigned char buf[BUFSIZE];    /* Buffer for incoming message */
  ErlMessage emsg;               /* Incoming message */
  
  ETERM *fromp, *tuplep, *fnp, *argp, *resp;
  int res;
  
  port = atoi(argv[1]);
  
  erl_init(NULL, 0);
  
  if (erl_connect_init(1, "secretcookie", 0) == -1)
    erl_err_quit("erl_connect_init");
  
  /* Make a listen socket */
  if ((listen = my_listen(port)) <= 0)
    erl_err_quit("my_listen");

  if (erl_publish(port) == -1)
    erl_err_quit("erl_publish");

  if ((fd = erl_accept(listen, &conn)) == ERL_ERROR)
    erl_err_quit("erl_accept");
  fprintf(stderr, "Connected to %s\n\r", conn.nodename);
  
  while (loop) {
    
    got = erl_receive_msg(fd, buf, BUFSIZE, &emsg);
    if (got == ERL_TICK) {
      /* ignore */
    } else if (got == ERL_ERROR) {
      loop = 0;
    } else {
      
      if (emsg.type == ERL_REG_SEND) {
        fromp = erl_element(2, emsg.msg);
        tuplep = erl_element(3, emsg.msg);
        fnp = erl_element(1, tuplep);
        argp = erl_element(2, tuplep);
        
        if (strncmp(ERL_ATOM_PTR(fnp), "foo", 3) == 0) {
          res = foo(ERL_INT_VALUE(argp));
        } else if (strncmp(ERL_ATOM_PTR(fnp), "bar", 3) == 0) {
          res = bar(ERL_INT_VALUE(argp));
        }
        
        resp = erl_format("{cnode, ~i}", res);
        erl_send(fd, fromp, resp);

        erl_free_term(emsg.from);
        erl_free_term(emsg.msg);
        erl_free_term(fromp);
        erl_free_term(tuplep);
        erl_free_term(fnp);
        erl_free_term(argp);
        erl_free_term(resp);
      }
    }
  } /* while */
}

int my_listen(int port) {
  int listen_fd;
  struct sockaddr_in addr;
  int on = 1;
  
  if ((listen_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    return (-1);
  
  setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on));
  
  memset((void *) &addr, 0, (size_t) sizeof (addr));
  addr.sin_family = AF_INET;
  addr.sin_port = htons(port);
  addr.sin_addr.s_addr = htonl(INADDR_ANY);
  
  if (bind(listen_fd, (struct sockaddr *) &addr, sizeof (addr)) < 0)
    return (-1);
  
  listen(listen_fd, 5);
  return listen_fd;
}