Доброго всем!
Решил освоить, однако лезут ошибки в талмутном примере.
представлюсь:
uname -a
Linux myhost 2.6.31-ARCH #1 SMP PREEMPT Tue Oct 13 13:36:23 CEST 2009 i686 Intel(R) Celeron(R) M processor 1.60GHz GenuineIntel GNU/Linux

/***********************************************************************
* Code listing from "Advanced Linux Programming," by CodeSourcery LLC  *
* Copyright (C) 2001 by New Riders Publishing                          *
* See COPYRIGHT for license information.                               *
***********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
/* Read text from the socket and print it out.  Continue until the
   socket closes.  Return non-zero if the client sent a "quit"
   message, zero otherwise.  */
int server (int client_socket)
{
  while (1) {
    int length;
    char* text;
    /* First, read the length of the text message from the socket.  If
       read returns zero, the client closed the connection.  */
    if (read (client_socket, &length, sizeof (length)) == 0)
      return 0;
    /* Allocate a buffer to hold the text.  */
    text = (char*) malloc (length);
    /* Read the text itself, and print it.  */
    read (client_socket, text, length);
    printf ("%s\n", text);
    /* Free the buffer.  */
    free (text);
    /* If the client sent the message "quit", we're all done.  */
    if (!strcmp (text, "quit"))
      return 1;
  }
}
int main (int argc, char* const argv[])
{
  const char* const socket_name = argv[1];
  int socket_fd;
  struct sockaddr_un name;
  int client_sent_quit_message;
  /* Create the socket.  */
  socket_fd = socket (PF_LOCAL, SOCK_STREAM, 0);
  /* Indicate this is a server.  */
  name.sun_family = AF_LOCAL;
  strcpy (name.sun_path, socket_name);
  bind (socket_fd, &name, SUN_LEN (&name));
  /* Listen for connections.  */
  listen (socket_fd, 5);
  /* Repeatedly accept connections, spinning off one server() to deal
     with each client.  Continue until a client sends a "quit" message.  */
  do {
    struct sockaddr_un client_name;
    socklen_t client_name_len;
    int client_socket_fd;
    /* Accept a connection.  */
    client_socket_fd = accept (socket_fd, &client_name, &client_name_len);
    /* Handle the connection.  */
    client_sent_quit_message = server (client_socket_fd);
    /* Close our end of the connection.  */
    close (client_socket_fd);
  }
  while (!client_sent_quit_message);
  /* Remove the socket file.  */
  close (socket_fd);
  unlink (socket_name);
  return 0;
}

при компиляции имею:

socket-server.c: In function 'main':
socket-server.c:53: warning: passing argument 2 of 'bind' from incompatible pointer type
/usr/include/sys/socket.h:115: note: expected 'const struct sockaddr *' but argument is of type 'struct sockaddr_un *'
socket-server.c:65: warning: passing argument 2 of 'accept' from incompatible pointer type
/usr/include/sys/socket.h:214: note: expected 'struct sockaddr * __restrict__' but argument is of type 'struct sockaddr_un *'

запуск делаю:
./socket-server /tmp/socket

клиентской программой отправляю сообщение ./socket-client ./tmp "hi"
и получаю на сервере "Segmentation fault"

клиентский код, наврятли, но если нужен:

/***********************************************************************
* Code listing from "Advanced Linux Programming," by CodeSourcery LLC  *
* Copyright (C) 2001 by New Riders Publishing                          *
* See COPYRIGHT for license information.                               *
***********************************************************************/
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
/* Write TEXT to the socket given by file descriptor SOCKET_FD.  */
void write_text (int socket_fd, const char* text)
{
  /* Write the number of bytes in the string, including
     NUL-termination.  */
  int length = strlen (text) + 1;
  write (socket_fd, &length, sizeof (length));
  /* Write the string.  */
  write (socket_fd, text, length);
}
int main (int argc, char* const argv[])
{
  const char* const socket_name = argv[1];
  const char* const message = argv[2];
  int socket_fd;
  struct sockaddr_un name;
  /* Create the socket.  */
  socket_fd = socket (PF_LOCAL, SOCK_STREAM, 0);
  /* Store the server's name in the socket address.  */
  name.sun_family = AF_LOCAL;
  strcpy (name.sun_path, socket_name);
  /* Connect the socket.  */
  connect (socket_fd, &name, SUN_LEN (&name));
  /* Write the text on the command line to the socket.  */
  write_text (socket_fd, message);
  close (socket_fd);
  return 0;
}

google послал гулять далеко на восток :(