Simple Contribution to gdb (fwd)

[David Whedon <davidw@gordian.com>]

I sent this to bug-gdb, but perhaps this is a better place to send it.

-David

---------- Forwarded message ----------
Date: Tue, 4 Aug 1998 12:49:32 -0700 (PDT)
From: David Whedon <davidw@gordian.com>
To: bug-gdb@prep.ai.mit.edu
Subject: Simple Contribution to gdb

Gdb Maintainers,

I made some small changes to ser-tcp.c that I hope will be incorporated in
the next release of gdb.  Debugging remotely over the ethernet is a whole
lot easier if UDP packets are sent rather than tcp packets since the code
on the stub side ends up being simpler.  All the changes were made in
tcp_open(), in ser-tcp.c.

I changed the function so that a UDP socket will be opened if:
 
target remote hostname:port/udp

is entered on the command line.

Thanks for your time maintaining such a useful tool,

David Whedon

-------begin modified tcp_open() -------------

/* Open up a raw tcp socket */

static int
tcp_open(scb, name)
     serial_t scb;
     const char *name;
{

  /* 
     this function has been modified to support UDP between the host and
the 
     remote target.  UDP is specified by the command:
     target remote hostname:port/udp
  */

  char *port_str; 
  int port;
  struct hostent *hostent;
  struct sockaddr_in sockaddr;
  int tmp;
  char hostname[100];
  struct protoent *protoent;
  int i;

  char protocol[16];

  port_str = strchr (name, ':');
  
  if (!port_str)
    error ("tcp_open: No colon in host name!"); /* Shouldn't ever happen
*/
  
  tmp = min (port_str - name, (int) sizeof hostname - 1);
  strncpy (hostname, name, tmp); /* Don't want colon */
  hostname[tmp] = '\000';       /* Tie off host name */
  
  port = atoi (port_str + 1);
  
  if(strchr (name, '/')!= NULL){  
    strncpy(protocol , strchr (name, '/')+1, sizeof(protocol));
    if( strncmp(protocol, "udp", sizeof("udp") )){
        error("tcp_open: unknown protocol");
    }
  }
  else
    strcpy(protocol, "tcp");
  
  
  hostent = gethostbyname (hostname);
  
  if (!hostent)
    {
      fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
      errno = ENOENT;
      return -1;
    }
  
  for (i = 1; i <= 15; i++)
    {
      
      if(!strcmp(protocol, "udp")){
        scb->fd = socket (PF_INET, SOCK_DGRAM, 0);
        if (scb->fd < 0)
          return -1;
      }
      else { /* if(!strcmp(protocol, "tcp")); */
        scb->fd = socket (PF_INET, SOCK_STREAM, 0);
        if (scb->fd < 0)
          return -1;
      }
      
      /* Allow rapid reuse of this port. */
      tmp = 1;
      setsockopt (scb->fd, SOL_SOCKET, SO_REUSEADDR, (char *)&tmp,
sizeof(tmp));

      /* Enable TCP keep alive process. */
      tmp = 1;
      setsockopt (scb->fd, SOL_SOCKET, SO_KEEPALIVE, (char *)&tmp,
sizeof(tmp));

      sockaddr.sin_family = PF_INET;
      sockaddr.sin_port = htons(port);
   memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
              sizeof (struct in_addr));

      if (!connect (scb->fd, (struct sockaddr *) &sockaddr,
sizeof(sockaddr)))
        break;

      close (scb->fd);
      scb->fd = -1;
      
/* We retry for ECONNREFUSED because that is often a temporary condition,
which
   happens when the server is being restarted.  */

      if (errno != ECONNREFUSED)
        return -1;
      
      sleep (1);
    }
  
  
  if(!strcmp(protocol, "tcp")){
    protoent = getprotobyname ("tcp");
    if (!protoent)
      return -1;
    
    tmp = 1;
    if (setsockopt (scb->fd, protoent->p_proto, TCP_NODELAY,
                    (char *)&tmp, sizeof(tmp)))
      return -1;
  }
  
  signal(SIGPIPE, SIG_IGN);     /* If we don't do this, then GDB simply
exits
                                   when the remote side dies.  */
  
  return 0;
}




------------end tcp_open()---------------------