Include @<ctype.h>@.

[mLib] / ident.c

/* -*-c-*-
 *
 * $Id: ident.c,v 1.3 2000/10/08 11:17:45 mdw Exp $
 *
 * Nonblocking RFC931 client
 *
 * (c) 1999 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: ident.c,v $
 * Revision 1.3  2000/10/08 11:17:45  mdw
 * (ident_socket): change sizes to be @size_t@.
 *
 * Revision 1.2  2000/06/17 10:38:35  mdw
 * Track changes to selbuf interface.
 *
 * Revision 1.1  1999/10/04 21:41:58  mdw
 * Added ident client from `fw'.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <unistd.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include "conn.h"
#include "dstr.h"
#include "exc.h"
#include "ident.h"
#include "selbuf.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @next@ --- *
 *
 * Arguments:	@char **pp@ = address of string pointer
 *
 * Returns:	Address of next token.
 *
 * Use:		Reads the next token from the result string.  Tokens are
 *		terminated by whitespace, or `:' or `,' characters.  The
 *		result string has had `\' escapes removed; it's stored in
 *		the same memory as the input string.  The actual content
 *		of the delimiter doesn't seem to be interesting, so it
 *		gets thrown away.
 */

static char *next(char **pp)
{
  char *p, *q, *r;

  /* --- Deal with reads past the end of the string --- */

  if (!*pp)
    return ("");

  /* --- Initialize various pointers into the string --- */

  p = q = r = *pp;

  /* --- Skip past any leading whitespace --- */

  while (isspace((unsigned char)*p))
    p++;

  /* --- Now start work on the string itself --- */

  for (;;) {
    if (*p == 0 || *p == ':' || *p == ',' || isspace((unsigned char)*p))
      break;
    else if (*p == '\\') {
      p++;
      if (!*p) {
	*q++ = '\\';
	break;
      }
    }
    *q++ = *p++;
  }

  /* --- Tidy up afterwards --- */

  while (isspace((unsigned char)*p))
    p++;
  if (*p == 0)
    *pp = 0;
  else if (*p == ':' || *p == ',')
    *pp = p + 1;
  else
    *pp = p;
  *q = 0;

  return (r);
}

/* --- @parse@ --- *
 *
 * Arguments:	@char *p@ = pointer to input string from identd
 *		@ident_reply *i@ = pointer to output block
 *
 * Returns:	---
 *
 * Use:		Parses a result string from an RFC931 (identd) server.
 */

static void parse(char *p, ident_reply *i)
{
  char *q;

  /* --- Read the source and destination port numbers --- */

  i->sport = atoi(next(&p));
  i->dport = atoi(next(&p));

  /* --- Find out what sort of a reply this is --- */

  q = next(&p);
  if (strcmp(q, "USERID") == 0) {
    i->type = IDENT_USERID;
    i->u.userid.os = next(&p);
    i->u.userid.user = next(&p);
  } else if (strcmp(q, "ERROR") == 0) {
    i->type = IDENT_ERROR;
    i->u.error = next(&p);
  } else
    i->type = IDENT_BAD;
}

/* --- @line@ --- *
 *
 * Arguments:	@char *s@ = pointer to string from ident server
 *		@void *p@ = pointer to my request block
 *
 * Returns:	---
 *
 * Use:		Handles a string from an ident server.
 */

static void line(char *s, void *p)
{
  ident_request *rq = p;

  rq->state = IDENT_DONE;
  close(rq->b.reader.fd);
  if (!s)
    rq->func(0, rq->p);
  else {
    ident_reply i;
    parse(s, &i);
    rq->func(&i, rq->p);
  }
  selbuf_destroy(&rq->b);
}

/* --- @connected@ --- *
 *
 * Arguments:	@int fd@ = file descriptor
 *		@void *p@ = pointer to request block
 *
 * Returns:	---
 *
 * Use:		Handles a connection to a remote ident server.
 */

static void connected(int fd, void *p)
{
  ident_request *rq = p;
  dstr d = DSTR_INIT;

  /* --- Handle an error during the connect --- */

  if (fd < 0)
    goto fail_0;

  /* --- Initialize the string to send to the remote host --- */

  TRY {
    dstr_putf(&d, "%u, %u\r\n",
	      ntohs(rq->remote.sin_port), ntohs(rq->local.sin_port));
  } CATCH switch (exc_type) {
    case EXC_NOMEM:
      EXIT_TRY;
      goto fail_1;
    default:
      RETHROW;
  } END_TRY;

  /* --- Do the rest of the work --- */

  if (write(fd, d.buf, d.len) < d.len)
    goto fail_1;
  dstr_destroy(&d);
  rq->state = IDENT_READ;
  selbuf_init(&rq->b, rq->s, fd, line, rq);
  return;

  /* --- Tidy up after misfortunes --- */

fail_1:
  dstr_destroy(&d);
  close(fd);
fail_0:
  rq->state = IDENT_DONE;
  rq->func(0, rq->p);
}

/* --- @ident_abort@ --- *
 *
 * Arguments:	@ident_request *rq@ = pointer to request block
 *
 * Returns:	---
 *
 * Use:		Cancels an ident request in progress.
 */

void ident_abort(ident_request *rq)
{
  switch (rq->state) {
    case IDENT_CONN:
      conn_kill(&rq->c);
      break;
    case IDENT_READ:
      close(rq->b.reader.fd);
      selbuf_destroy(&rq->b);
      break;
  }
}

/* --- @go@ --- *
 *
 * Arguments:	@ident_request *rq@ = pointer to request block
 *
 * Returns:	---
 *
 * Use:		Starts a connection to the remote ident server.
 */

static void go(ident_request *rq)
{
  int fd;
  struct sockaddr_in sin;
  int opt;

  /* --- Create the socket I'll use --- */
  
  if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
    goto fail_0;
  memset(&sin, 0, sizeof(sin));
  sin.sin_family = AF_INET;
  sin.sin_port = 0;
  sin.sin_addr = rq->local.sin_addr;
  if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
    goto fail_1;

  /* --- Out-of-band data would confuse us --- */

  opt = 1;
  setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));

  /* --- Start a connection to the remote server --- */

  sin.sin_family = AF_INET;
  sin.sin_port = htons(113);
  sin.sin_addr = rq->remote.sin_addr;
  conn_init(&rq->c, rq->s, fd, (struct sockaddr *)&sin, sizeof(sin),
	    connected, rq);

  /* --- Finish off initializing the block --- */

  rq->state = IDENT_CONN;
  return;

  /* --- Tidy up after lossage --- */

fail_1:
  close(fd);
fail_0:
  rq->state = IDENT_DONE;
  rq->func(0, rq->p);
}

/* --- @ident@ --- *
 *
 * Arguments:	@ident_request *rq@ = pointer to request block
 *		@sel_state *s@ = I/O multiplexor
 *		@const struct sockaddr_in *local, *remote@ = addresses
 *		@void (*func)(ident_reply *i, void *p)@ = handler function
 *		@void *p@ = argument for handler
 *
 * Returns:	---
 *
 * Use:		Initializes an ident request.
 */

void ident(ident_request *rq, sel_state *s,
	   const struct sockaddr_in *local,
	   const struct sockaddr_in *remote, 
	   void (*func)(ident_reply */*i*/, void */*p*/),
	   void *p)
{
  memcpy(&rq->local, local, sizeof(rq->local));
  memcpy(&rq->remote, remote, sizeof(rq->remote));
  rq->func = func;
  rq->p = p;
  rq->s = s;
  go(rq);
}

/* --- @ident_socket@ --- *
 *
 * Arguments:	@ident_request *rq@ = pointer to request block
 *		@sel_state *s@ = I/O multiplexor
 *		@int sk@ = connected socket file descriptor
 *		@void (*func)(ident_reply *i, void *p)@ = handler function
 *		@void *p@ = argument for handler
 *
 * Returns:	---
 *
 * Use:		An alternative interface to @ident@.  Initializes an ident
 *		request from a connected socket, rather than from an explicit
 *		address.  This will call @getsockname@ and @getpeername@ to
 *		find out what the socket is actually connected to, which adds
 *		convenience but wastes time.
 */

void ident_socket(ident_request *rq, sel_state *s, int sk,
		  void (*func)(ident_reply */*i*/, void */*p*/),
		  void *p)
{
  size_t sinsz;
  if ((sinsz = sizeof(struct sockaddr_in),
       getsockname(sk, (struct sockaddr *)&rq->local, &sinsz)) ||
      (sinsz = sizeof(struct sockaddr_in),
       getpeername(sk, (struct sockaddr *)&rq->remote, &sinsz))) {
    rq->state = IDENT_DONE;
    func(0, p);
    return;
  }

  rq->func = func;
  rq->p = p;
  rq->s = s;
  go(rq);
}

/*----- That's all, folks -------------------------------------------------*/