xref: /netbsd/lib/libutil/getbootfile.c (revision c4a72b64)
1 /*	$NetBSD: getbootfile.c,v 1.2 2002/09/12 14:42:15 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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 __RCSID("$NetBSD: getbootfile.c,v 1.2 2002/09/12 14:42:15 christos Exp $");
42 #endif
43 
44 #include <sys/param.h>
45 #include <sys/sysctl.h>
46 #include <machine/cpu.h>
47 #include <paths.h>
48 #include <util.h>
49 
50 #ifdef CPU_BOOTED_KERNEL
51 static char name[MAXPATHLEN];
52 #endif
53 
54 const char *
55 getbootfile(void)
56 {
57 #ifdef CPU_BOOTED_KERNEL
58 	int mib[2];
59 	size_t size;
60 #endif
61 	const char *kernel;
62 
63 	kernel = _PATH_UNIX;
64 #ifdef CPU_BOOTED_KERNEL
65 	/* find real boot-kernel name */
66 	mib[0] = CTL_MACHDEP;
67 	mib[1] = CPU_BOOTED_KERNEL;
68 	size = sizeof(name) - 1;
69 	if (sysctl(mib, 2, name + 1, &size, NULL, NULL) == 0) {
70 		/*
71 		 * traditionally, this sysctl returns the relative
72 		 * path of the kernel with the leading slash stripped
73 		 * -- could be empty, though (e.g. when netbooting).
74 		 */
75 		if (name[1] != '\0') {
76 			name[0] = '/';
77 			kernel = name;
78 		}
79 
80 		/* check if we got a valid and 'secure' filename */
81 		if (strcmp(kernel, _PATH_UNIX) != 0 &&
82 		    secure_path(kernel) != 0) {
83 			/* doesn't seems so, fall back to default */
84 			kernel = _PATH_UNIX;
85 		}
86 	}
87 #endif
88 
89 	return (kernel);
90 }
91