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asysctl.c revision 1.1 
      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 }
     93