contrib/libarchive-2/libarchive/archive_check_magic.c

   1 /*-
   2  * Copyright (c) 2003-2007 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  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "archive_platform.h"
  27 __FBSDID("$FreeBSD: src/lib/libarchive/archive_check_magic.c,v 1.8 2007/04/02 00:15:45 kientzle Exp $");
  28
  29 #ifdef HAVE_SYS_TYPES_H
  30 #include <sys/types.h>
  31 #endif
  32
  33 #include <stdio.h>
  34 #ifdef HAVE_STDLIB_H
  35 #include <stdlib.h>
  36 #endif
  37 #ifdef HAVE_STRING_H
  38 #include <string.h>
  39 #endif
  40 #ifdef HAVE_UNISTD_H
  41 #include <unistd.h>
  42 #endif
  43
  44 #include "archive_private.h"
  45
  46 static void
  47 errmsg(const char *m)
  48 {
  49         write(STDERR_FILENO, m, strlen(m));
  50 }
  51
  52 static void
  53 diediedie(void)
  54 {
  55         *(char *)0 = 1; /* Deliberately segfault and force a coredump. */
  56         _exit(1);       /* If that didn't work, just exit with an error. */
  57 }
  58
  59 static const char *
  60 state_name(unsigned s)
  61 {
  62         switch (s) {
  63         case ARCHIVE_STATE_NEW:         return ("new");
  64         case ARCHIVE_STATE_HEADER:      return ("header");
  65         case ARCHIVE_STATE_DATA:        return ("data");
  66         case ARCHIVE_STATE_EOF:         return ("eof");
  67         case ARCHIVE_STATE_CLOSED:      return ("closed");
  68         case ARCHIVE_STATE_FATAL:       return ("fatal");
  69         default:                        return ("??");
  70         }
  71 }
  72
  73
  74 static void
  75 write_all_states(unsigned int states)
  76 {
  77         unsigned int lowbit;
  78
  79         /* A trick for computing the lowest set bit. */
  80         while ((lowbit = states & (-states)) != 0) {
  81                 states &= ~lowbit;              /* Clear the low bit. */
  82                 errmsg(state_name(lowbit));
  83                 if (states != 0)
  84                         errmsg("/");
  85         }
  86 }
  87
  88 /*
  89  * Check magic value and current state; bail if it isn't valid.
  90  *
  91  * This is designed to catch serious programming errors that violate
  92  * the libarchive API.
  93  */
  94 void
  95 __archive_check_magic(struct archive *a, unsigned int magic,
  96     unsigned int state, const char *function)
  97 {
  98         if (a->magic != magic) {
  99                 errmsg("INTERNAL ERROR: Function ");
 100                 errmsg(function);
 101                 errmsg(" invoked with invalid struct archive structure.\n");
 102                 diediedie();
 103         }
 104
 105         if (state == ARCHIVE_STATE_ANY)
 106                 return;
 107
 108         if ((a->state & state) == 0) {
 109                 errmsg("INTERNAL ERROR: Function '");
 110                 errmsg(function);
 111                 errmsg("' invoked with archive structure in state '");
 112                 write_all_states(a->state);
 113                 errmsg("', should be in state '");
 114                 write_all_states(state);
 115                 errmsg("'\n");
 116                 diediedie();
 117         }
 118 }