contrib/libarchive-1.3.1/libarchive/archive_check_magic.c

   1 /*-
   2  * Copyright (c) 2003-2004 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "archive_platform.h"
  28 __FBSDID("$FreeBSD: src/lib/libarchive/archive_check_magic.c,v 1.5 2004/10/18 04:34:30 kientzle Exp $");
  29
  30 #include <sys/types.h>
  31
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35
  36 #include "archive_private.h"
  37
  38 static void
  39 errmsg(const char *m)
  40 {
  41         write(STDERR_FILENO, m, strlen(m));
  42 }
  43
  44 static void
  45 diediedie(void)
  46 {
  47         *(char *)0 = 1; /* Deliberately segfault and force a coredump. */
  48         _exit(1);       /* If that didn't work, just exit with an error. */
  49 }
  50
  51 static const char *
  52 state_name(unsigned s)
  53 {
  54         switch (s) {
  55         case ARCHIVE_STATE_NEW:         return ("new");
  56         case ARCHIVE_STATE_HEADER:      return ("header");
  57         case ARCHIVE_STATE_DATA:        return ("data");
  58         case ARCHIVE_STATE_EOF:         return ("eof");
  59         case ARCHIVE_STATE_CLOSED:      return ("closed");
  60         case ARCHIVE_STATE_FATAL:       return ("fatal");
  61         default:                        return ("??");
  62         }
  63 }
  64
  65
  66 static void
  67 write_all_states(int states)
  68 {
  69         unsigned lowbit;
  70
  71         /* A trick for computing the lowest set bit. */
  72         while ((lowbit = states & (-states)) != 0) {
  73                 states &= ~lowbit;              /* Clear the low bit. */
  74                 errmsg(state_name(lowbit));
  75                 if (states != 0)
  76                         errmsg("/");
  77         }
  78 }
  79
  80 /*
  81  * Check magic value and current state; bail if it isn't valid.
  82  *
  83  * This is designed to catch serious programming errors that violate
  84  * the libarchive API.
  85  */
  86 void
  87 __archive_check_magic(struct archive *a, unsigned magic, unsigned state,
  88     const char *function)
  89 {
  90         if (a->magic != magic) {
  91                 errmsg("INTERNAL ERROR: Function ");
  92                 errmsg(function);
  93                 errmsg(" invoked with invalid struct archive structure.\n");
  94                 diediedie();
  95         }
  96
  97         if (state == ARCHIVE_STATE_ANY)
  98                 return;
  99
 100         if ((a->state & state) == 0) {
 101                 errmsg("INTERNAL ERROR: Function '");
 102                 errmsg(function);
 103                 errmsg("' invoked with archive structure in state '");
 104                 write_all_states(a->state);
 105                 errmsg("', should be in state '");
 106                 write_all_states(state);
 107                 errmsg("'\n");
 108                 diediedie();
 109         }
 110 }