lib/libarchive/archive_read_open_memory.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("$FreeBSD$");
  28
  29 #include <errno.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "archive.h"
  34
  35 /*
  36  * Glue to read an archive from a block of memory.
  37  *
  38  * This is mostly a huge help in building test harnesses;
  39  * test programs can build archives in memory and read them
  40  * back again without having to mess with files on disk.
  41  */
  42
  43 struct read_memory_data {
  44         unsigned char   *buffer;
  45         unsigned char   *end;
  46         ssize_t  read_size;
  47 };
  48
  49 static int      memory_read_close(struct archive *, void *);
  50 static int      memory_read_open(struct archive *, void *);
  51 #if ARCHIVE_API_VERSION < 2
  52 static ssize_t  memory_read_skip(struct archive *, void *, size_t request);
  53 #else
  54 static off_t    memory_read_skip(struct archive *, void *, off_t request);
  55 #endif
  56 static ssize_t  memory_read(struct archive *, void *, const void **buff);
  57
  58 int
  59 archive_read_open_memory(struct archive *a, void *buff, size_t size)
  60 {
  61         return archive_read_open_memory2(a, buff, size, size);
  62 }
  63
  64 /*
  65  * Don't use _open_memory2() in production code; the archive_read_open_memory()
  66  * version is the one you really want.  This is just here so that
  67  * test harnesses can exercise block operations inside the library.
  68  */
  69 int
  70 archive_read_open_memory2(struct archive *a, void *buff,
  71     size_t size, size_t read_size)
  72 {
  73         struct read_memory_data *mine;
  74
  75         mine = (struct read_memory_data *)malloc(sizeof(*mine));
  76         if (mine == NULL) {
  77                 archive_set_error(a, ENOMEM, "No memory");
  78                 return (ARCHIVE_FATAL);
  79         }
  80         memset(mine, 0, sizeof(*mine));
  81         mine->buffer = (unsigned char *)buff;
  82         mine->end = mine->buffer + size;
  83         mine->read_size = read_size;
  84         return (archive_read_open2(a, mine, memory_read_open,
  85                     memory_read, memory_read_skip, memory_read_close));
  86 }
  87
  88 /*
  89  * There's nothing to open.
  90  */
  91 static int
  92 memory_read_open(struct archive *a, void *client_data)
  93 {
  94         (void)a; /* UNUSED */
  95         (void)client_data; /* UNUSED */
  96         return (ARCHIVE_OK);
  97 }
  98
  99 /*
 100  * This is scary simple:  Just advance a pointer.  Limiting
 101  * to read_size is not technically necessary, but it exercises
 102  * more of the internal logic when used with a small block size
 103  * in a test harness.  Production use should not specify a block
 104  * size; then this is much faster.
 105  */
 106 static ssize_t
 107 memory_read(struct archive *a, void *client_data, const void **buff)
 108 {
 109         struct read_memory_data *mine = (struct read_memory_data *)client_data;
 110         ssize_t size;
 111
 112         (void)a; /* UNUSED */
 113         *buff = mine->buffer;
 114         size = mine->end - mine->buffer;
 115         if (size > mine->read_size)
 116                 size = mine->read_size;
 117         mine->buffer += size;
 118         return (size);
 119 }
 120
 121 /*
 122  * Advancing is just as simple.  Again, this is doing more than
 123  * necessary in order to better exercise internal code when used
 124  * as a test harness.
 125  */
 126 #if ARCHIVE_API_VERSION < 2
 127 static ssize_t
 128 memory_read_skip(struct archive *a, void *client_data, size_t skip)
 129 #else
 130 static off_t
 131 memory_read_skip(struct archive *a, void *client_data, off_t skip)
 132 #endif
 133 {
 134         struct read_memory_data *mine = (struct read_memory_data *)client_data;
 135
 136         (void)a; /* UNUSED */
 137         if ((off_t)skip > (off_t)(mine->end - mine->buffer))
 138                 skip = mine->end - mine->buffer;
 139         /* Round down to block size. */
 140         skip /= mine->read_size;
 141         skip *= mine->read_size;
 142         mine->buffer += skip;
 143         return (skip);
 144 }
 145
 146 /*
 147  * Close is just cleaning up our one small bit of data.
 148  */
 149 static int
 150 memory_read_close(struct archive *a, void *client_data)
 151 {
 152         struct read_memory_data *mine = (struct read_memory_data *)client_data;
 153         (void)a; /* UNUSED */
 154         free(mine);
 155         return (ARCHIVE_OK);
 156 }