busybox/libbb/kernel_version.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"
/* After libbb.h, since it needs sys/types.h on some systems */
#include <sys/utsname.h>  /* for uname(2) */

/* Returns current kernel version encoded as major*65536 + minor*256 + patch,
 * so, for example,  to check if the kernel is greater than 2.2.11:
 *
 *     if (get_linux_version_code() > KERNEL_VERSION(2,2,11)) { <stuff> }
 */
int FAST_FUNC get_linux_version_code(void)
{
	struct utsname name;
	char *t;
	int r;

	uname(&name); /* never fails */
	t = name.release - 1;
	r = 1;
	do {
		r <<= 8;
		if (t) {
			r += atoi(++t);
			t = strchr(t, '.');
		}
	} while (r < 0x1000000);
	return r - 0x1000000;
}