lib/libc/gen/asysctl.c

   1 /*      $NetBSD: asysctl.c,v 1.1 2014/06/13 15:45:05 joerg Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
   5  *      All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Joerg Sonnenberger.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __RCSID("$NetBSD: asysctl.c,v 1.1 2014/06/13 15:45:05 joerg Exp $");
  34
  35 #include "namespace.h"
  36 #include <sys/sysctl.h>
  37 #include <errno.h>
  38 #include <limits.h>
  39 #include <stdlib.h>
  40
  41 __weak_alias(asysctl,_asysctl)
  42 __weak_alias(asysctlbyname,_asysctlbyname)
  43
  44 void *
  45 asysctl(const int *oids, size_t oidlen, size_t *len)
  46 {
  47         void *data;
  48
  49         *len = 0;
  50         data = NULL;
  51
  52         for (;;) {
  53                 if (sysctl(oids, oidlen, data, len, NULL, 0) == 0) {
  54                         if (*len == 0) {
  55                                 free(data);
  56                                 return NULL;
  57                         }
  58                         if (data != NULL)
  59                                 return data;
  60                         errno = ENOMEM;
  61                 }
  62                 free(data);
  63                 if (errno == ENOMEM && *len != SIZE_MAX) {
  64                         if (*len > SIZE_MAX / 2)
  65                                 *len = SIZE_MAX;
  66                         else
  67                                 *len *= 2;
  68                         data = malloc(*len);
  69                         if (data == NULL) {
  70                                 *len = SIZE_MAX;
  71                                 return NULL;
  72                         }
  73                         continue;
  74                 }
  75                 *len = SIZE_MAX;
  76                 return NULL;
  77         }
  78 }
  79
  80 void *
  81 asysctlbyname(const char *gname, size_t *len)
  82 {
  83         int name[CTL_MAXNAME];
  84         u_int namelen;
  85
  86         if (sysctlgetmibinfo(gname, &name[0], &namelen, NULL, NULL, NULL,
  87                              SYSCTL_VERSION)) {
  88                 *len = SIZE_MAX;
  89                 return NULL;
  90         }
  91         return asysctl(&name[0], namelen, len);
  92 }