xref: /freebsd/crypto/heimdal/lib/roken/getdtablesize.c (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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 #include <config.h>
35 
36 #include "roken.h"
37 
38 #ifdef HAVE_SYS_TYPES_H
39 #include <sys/types.h>
40 #endif
41 #ifdef TIME_WITH_SYS_TIME
42 #include <sys/time.h>
43 #include <time.h>
44 #elif defined(HAVE_SYS_TIME_H)
45 #include <sys/time.h>
46 #else
47 #include <time.h>
48 #endif
49 #ifdef HAVE_SYS_PARAM_H
50 #include <sys/param.h>
51 #endif
52 #ifdef HAVE_UNISTD_H
53 #include <unistd.h>
54 #endif
55 
56 #ifdef HAVE_SYS_RESOURCE_H
57 #include <sys/resource.h>
58 #endif
59 
60 #ifdef HAVE_SYS_SYSCTL_H
61 #include <sys/sysctl.h>
62 #endif
63 
64 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
65 getdtablesize(void)
66 {
67   int files = -1;
68 #if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
69   files = sysconf(_SC_OPEN_MAX);
70 #else /* !defined(HAVE_SYSCONF) */
71 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
72   struct rlimit res;
73   if (getrlimit(RLIMIT_NOFILE, &res) == 0)
74     files = res.rlim_cur;
75 #else /* !definded(HAVE_GETRLIMIT) */
76 #if defined(HAVE_SYSCTL) && defined(CTL_KERN) && defined(KERN_MAXFILES)
77   int mib[2];
78   size_t len;
79 
80   mib[0] = CTL_KERN;
81   mib[1] = KERN_MAXFILES;
82   len = sizeof(files);
83   sysctl(&mib, 2, &files, sizeof(files), NULL, 0);
84 #endif /* defined(HAVE_SYSCTL) */
85 #endif /* !definded(HAVE_GETRLIMIT) */
86 #endif /* !defined(HAVE_SYSCONF) */
87 
88 #ifdef OPEN_MAX
89   if (files < 0)
90     files = OPEN_MAX;
91 #endif
92 
93 #ifdef NOFILE
94   if (files < 0)
95     files = NOFILE;
96 #endif
97 
98   return files;
99 }
100