nmap/nsock/src/netutils.c

/***************************************************************************
 * netutils.c -- This contains some useful little network/socket related   *
 * utility functions.                                                      *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
 *                                                                         *
 * The nsock parallel socket event library is (C) 1999-2012 Insecure.Com   *
 * LLC This library is free software; you may redistribute and/or          *
 * modify it under the terms of the GNU General Public License as          *
 * published by the Free Software Foundation; Version 2.  This guarantees  *
 * your right to use, modify, and redistribute this software under certain *
 * conditions.  If this license is unacceptable to you, Insecure.Com LLC   *
 * may be willing to sell alternative licenses (contact                    *
 * sales@insecure.com ).                                                   *
 *                                                                         *
 * As a special exception to the GPL terms, Insecure.Com LLC grants        *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included docs/licenses/OpenSSL.txt file, and distribute   *
 * linked combinations including the two. You must obey the GNU GPL in all *
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 * but you are not obligated to do so.                                     *
 *                                                                         *
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 * agreement takes precedence over this comment.                           *
 *                                                                         *
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 * have been found so far).                                                *
 *                                                                         *
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 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       *
 * General Public License v2.0 for more details                            *
 * (http://www.gnu.org/licenses/gpl-2.0.html).                             *
 *                                                                         *
 ***************************************************************************/

/* $Id$ */

#include "netutils.h"
#include "error.h"

#if WIN32
#include "Winsock2.h"
#endif

#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif

static int netutils_debugging = 0;

/* maximize the number of file descriptors (including sockets) allowed for this
 * process and return that maximum value (note -- you better not actually open
 * this many -- stdin, stdout, other files opened by libraries you use, etc. all
 * count toward this limit.  Leave a little slack */
int maximize_fdlimit(void) { 

#ifndef WIN32
  struct rlimit r; 
  static int maxfds = -1;

  if (maxfds > 0)
    return maxfds;

#if(defined(RLIMIT_NOFILE))
  if (!getrlimit(RLIMIT_NOFILE, &r)) {
    r.rlim_cur = r.rlim_max;
    if (setrlimit(RLIMIT_NOFILE, &r))
      if (netutils_debugging)
        perror("setrlimit RLIMIT_NOFILE failed");

    if (!getrlimit(RLIMIT_NOFILE, &r)) {
      maxfds = r.rlim_cur;
      return maxfds;
    } else {
      return 0;
    }
  }
#endif

#if(defined(RLIMIT_OFILE) && !defined(RLIMIT_NOFILE))
  if (!getrlimit(RLIMIT_OFILE, &r)) {
    r.rlim_cur = r.rlim_max;
    if (setrlimit(RLIMIT_OFILE, &r))
      if (netutils_debugging)
        perror("setrlimit RLIMIT_OFILE failed");

    if (!getrlimit(RLIMIT_OFILE, &r)) {
      maxfds = r.rlim_cur;
      return maxfds;
    } else {
      return 0;
    }
  }
#endif
#endif /* !WIN32 */
  return 0;
}