/*      $NetBSD: asysctl.c,v 1.2 2017/01/10 17:45:58 christos Exp $ */

/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
*      All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Joerg Sonnenberger.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: asysctl.c,v 1.2 2017/01/10 17:45:58 christos Exp $");

#include "namespace.h"
#include <sys/sysctl.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>

__weak_alias(asysctl,_asysctl)
__weak_alias(asysctlbyname,_asysctlbyname)

void *
asysctl(const int *oids, size_t oidlen, size_t *len)
{
       void *data;

       *len = 0;
       data = NULL;

       for (;;) {
               if (sysctl(oids, (u_int)oidlen, data, len, NULL, 0) == 0) {
                       if (*len == 0) {
                               free(data);
                               return NULL;
                       }
                       if (data != NULL)
                               return data;
                       errno = ENOMEM;
               }
               free(data);
               if (errno == ENOMEM && *len != SIZE_MAX) {
                       if (*len > SIZE_MAX / 2)
                               *len = SIZE_MAX;
                       else
                               *len *= 2;
                       data = malloc(*len);
                       if (data == NULL) {
                               *len = SIZE_MAX;
                               return NULL;
                       }
                       continue;
               }
               *len = SIZE_MAX;
               return NULL;
       }
}

void *
asysctlbyname(const char *gname, size_t *len)
{
       int name[CTL_MAXNAME];
       u_int namelen;

       if (sysctlgetmibinfo(gname, &name[0], &namelen, NULL, NULL, NULL,
                            SYSCTL_VERSION)) {
               *len = SIZE_MAX;
               return NULL;
       }
       return asysctl(&name[0], namelen, len);
}