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      1 /*	$NetBSD: getbootfile.c,v 1.6 2016/01/25 18:14:04 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Thomas Klausner.
      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 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: getbootfile.c,v 1.6 2016/01/25 18:14:04 christos Exp $");
     35 #endif
     36 
     37 #include <sys/param.h>
     38 #include <sys/sysctl.h>
     39 #include <sys/cpu.h>
     40 #include <string.h>
     41 #include <paths.h>
     42 #include <util.h>
     43 
     44 #ifdef CPU_BOOTED_KERNEL
     45 static char name[MAXPATHLEN];
     46 #endif
     47 
     48 const char *
     49 getbootfile(void)
     50 {
     51 #ifdef CPU_BOOTED_KERNEL
     52 	int mib[2];
     53 	size_t size;
     54 #endif
     55 	const char *kernel;
     56 
     57 	kernel = _PATH_UNIX;
     58 #ifdef CPU_BOOTED_KERNEL
     59 	/* find real boot-kernel name */
     60 	mib[0] = CTL_MACHDEP;
     61 	mib[1] = CPU_BOOTED_KERNEL;
     62 	size = sizeof(name) - 1;
     63 	if (sysctl(mib, 2, name + 1, &size, NULL, 0) == 0) {
     64 		/*
     65 		 * traditionally, this sysctl returns the relative
     66 		 * path of the kernel with the leading slash stripped
     67 		 * -- could be empty, though (e.g. when netbooting).
     68 		 */
     69 		if (name[1] != '\0') {
     70 			name[0] = '/';
     71 			kernel = name;
     72 		}
     73 
     74 		/* check if we got a valid and 'secure' filename */
     75 		if (strcmp(kernel, _PATH_UNIX) != 0 &&
     76 		    secure_path(kernel) != 0) {
     77 			/* doesn't seems so, fall back to default */
     78 			kernel = _PATH_UNIX;
     79 		}
     80 	}
     81 #endif
     82 
     83 	return (kernel);
     84 }
     85