64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
/*-
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* Copyright (c) 2008 Yahoo!, Inc.
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* All rights reserved.
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* Written by: John Baldwin <jhb@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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/*
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* Returns true if the named feature is present in the currently
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* running kernel. A feature's presence is indicated by an integer
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* sysctl node called kern.feature.<feature> that is non-zero.
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*/
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int
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feature_present(const char *feature)
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{
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char *mib;
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size_t len;
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int i;
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if (asprintf(&mib, "kern.features.%s", feature) < 0)
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return (0);
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len = sizeof(i);
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if (sysctlbyname(mib, &i, &len, NULL, 0) < 0) {
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free(mib);
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return (0);
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}
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free(mib);
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if (len != sizeof(i))
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return (0);
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return (i != 0);
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}
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