diff options
author | jhb <jhb@FreeBSD.org> | 2008-01-10 22:11:21 +0000 |
---|---|---|
committer | jhb <jhb@FreeBSD.org> | 2008-01-10 22:11:21 +0000 |
commit | 34de26d1084ed5c82db694fb4ad5ca112722aa29 (patch) | |
tree | 6186b6f0c2a3d20926552fb47b23634d0326c0ef /lib/libc/gen/feature_present.c | |
parent | f261f9865b0f750ea6f3b27feebcf093412d9dbf (diff) | |
download | FreeBSD-src-34de26d1084ed5c82db694fb4ad5ca112722aa29.zip FreeBSD-src-34de26d1084ed5c82db694fb4ad5ca112722aa29.tar.gz |
Add a feature_present(3) function which checks to see if a named kernel
feature is present by checking the kern.features sysctl MIB.
MFC after: 1 week
Diffstat (limited to 'lib/libc/gen/feature_present.c')
-rw-r--r-- | lib/libc/gen/feature_present.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/lib/libc/gen/feature_present.c b/lib/libc/gen/feature_present.c new file mode 100644 index 0000000..7a2c282 --- /dev/null +++ b/lib/libc/gen/feature_present.c @@ -0,0 +1,62 @@ +/*- + * Copyright (c) 2008 Yahoo!, Inc. + * All rights reserved. + * Written by: John Baldwin <jhb@FreeBSD.org> + * + * 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. + * 3. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/sysctl.h> +#include <stdio.h> +#include <stdlib.h> + +/* + * Returns true if the named feature is present in the currently + * running kernel. A feature's presence is indicated by an integer + * sysctl node called kern.feature.<feature> that is non-zero. + */ +int +feature_present(const char *feature) +{ + char *mib; + size_t len; + int i; + + if (asprintf(&mib, "kern.features.%s", feature) < 0) + return (0); + len = sizeof(i); + if (sysctlbyname(mib, &i, &len, NULL, 0) < 0) { + free(mib); + return (0); + } + free(mib); + if (len != sizeof(i)) + return (0); + return (i != 0); +} |