socket.c

linux下的BBS

#include "socket.h"


int
get_connect (char *serv_name, unsigned short port_num)
{
  struct hostent *hp;
  struct sockaddr_in sa;
  int sockfd;

#ifdef DEBUG
  printf ("FUNC get_connect: getting IP address of server %s\n", serv_name);
#endif
  if ((hp = gethostbyname (serv_name)) == NULL) {
#ifdef DEBUG
    printf ("FUNC get_connect: Server does not exist: %s\n", serv_name);
#endif
    return SOCK_NOEXIST;
  }
#ifdef DEBUG
  printf ("FUNC get_connect: initializing the socket address of server.\n");
#endif
  memset (&sa, 0, sizeof (sa));
  memcpy ((char *) &(sa.sin_addr), hp->h_addr, hp->h_length);
  sa.sin_family = AF_INET;
  sa.sin_port = htons (port_num);

  if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {
#ifdef DEBUG
    perror (" FUNC: get_connect: socket cannot be opened\n");
#endif
    return SOCK_ERROR;
  }
  if (connect (sockfd, (struct sockaddr *) &sa, sizeof (sa)) < 0) {
#ifdef DEBUG
    printf ("FUNC: get_connect: can't connect to server: %s\n", serv_name);
#endif
    close (sockfd);
    return SOCK_NORESPOND;
  }
#ifdef DEBUG
  printf ("FUNC get_connect: Successfully connected to server %s\n",
    serv_name);
  printf ("FUNC get_connect: Socket number is %d\n", sockfd);
#endif
  return sockfd;
}

int
writesock (int sockfd, char *buff, int bufflen)
{
#ifdef DEBUG
  printf ("FUNC writesock: the buffer is %s\n", buff);
  printf ("FUNC writesock: the bufferlen is %d\n", bufflen);
  printf ("FUNC writesock: the sockfd is %d\n", sockfd);
#endif
  if ((send (sockfd, buff, bufflen, 0)) < 0) {
#ifdef DEBUG
    printf ("FUNC writesock: ERROR in writing line to socket.\n");
#endif
    return SOCK_ERROR;
  }
  return 0;
}


int
readsock (int sockfd, char *buff, int bufflen)
{
  int count, len_of_line = 1;

  if (recv (sockfd, buff, bufflen, MSG_PEEK) < 1) {
#ifdef DEBUG
    printf ("FUNC readsock: Error in reading line from socket.\n");
#endif
    return SOCK_ERROR;
  }
  for (count = 0; (buff[count] != '\n') && (count < (bufflen - 2));
    count++, len_of_line++);

  recv (sockfd, buff, len_of_line, 0);
  buff[len_of_line] = '\0';

  return 0;
}

int
writeln (int sockfd, char *buf)
{

  if ((writesock (sockfd, buf, strlen (buf))) == 0)
    return 0;
  else
    return SOCK_ERROR;
}

int
sockprintf (int socket, char *format, ...)
{
  va_list ap;
  char buf[8192];

  va_start (ap, format);
  vsprintf (buf, format, ap);
  va_end (ap);
  return writesock (socket, buf, strlen (buf));
}

int
sockgetline (int socket, char *buf, int len)
{
  while (--len) {
    if (read (socket, buf, 1) != 1)
      return -1;
    if (*buf == '\n')
      break;
    if (*buf != '\r')
      buf++;
  }
  *buf = 0;
  return 0;
}