lib/roken/getdtablesize.c

   1 /*
   2  * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 RCSID("$Id$");
  37 #endif
  38
  39 #include "roken.h"
  40
  41 #ifdef HAVE_SYS_TYPES_H
  42 #include <sys/types.h>
  43 #endif
  44 #ifdef TIME_WITH_SYS_TIME
  45 #include <sys/time.h>
  46 #include <time.h>
  47 #elif defined(HAVE_SYS_TIME_H)
  48 #include <sys/time.h>
  49 #else
  50 #include <time.h>
  51 #endif
  52 #ifdef HAVE_SYS_PARAM_H
  53 #include <sys/param.h>
  54 #endif
  55 #ifdef HAVE_UNISTD_H
  56 #include <unistd.h>
  57 #endif
  58
  59 #ifdef HAVE_SYS_RESOURCE_H
  60 #include <sys/resource.h>
  61 #endif
  62
  63 #ifdef HAVE_SYS_SYSCTL_H
  64 #include <sys/sysctl.h>
  65 #endif
  66
  67 int getdtablesize(void)
  68 {
  69   int files = -1;
  70 #if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
  71   files = sysconf(_SC_OPEN_MAX);
  72 #else /* !defined(HAVE_SYSCONF) */
  73 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
  74   struct rlimit res;
  75   if (getrlimit(RLIMIT_NOFILE, &res) == 0)
  76     files = res.rlim_cur;
  77 #else /* !definded(HAVE_GETRLIMIT) */
  78 #if defined(HAVE_SYSCTL) && defined(CTL_KERN) && defined(KERN_MAXFILES)
  79   int mib[2];
  80   size_t len;
  81
  82   mib[0] = CTL_KERN;
  83   mib[1] = KERN_MAXFILES;
  84   len = sizeof(files);
  85   sysctl(&mib, 2, &files, sizeof(files), NULL, 0);
  86 #endif /* defined(HAVE_SYSCTL) */
  87 #endif /* !definded(HAVE_GETRLIMIT) */
  88 #endif /* !defined(HAVE_SYSCONF) */
  89
  90 #ifdef OPEN_MAX
  91   if (files < 0)
  92     files = OPEN_MAX;
  93 #endif
  94
  95 #ifdef NOFILE
  96   if (files < 0)
  97     files = NOFILE;
  98 #endif
  99
 100   return files;
 101 }