lib/libutil/getbootfile.c

   1 /*      $NetBSD: getbootfile.c,v 1.5 2008/04/28 20:23:02 martin 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 1.5 2008/04/28 20:23:02 martin Exp $");
  35 #endif
  36
  37 #include <sys/param.h>
  38 #include <sys/sysctl.h>
  39 #include <machine/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 }