lib/libarchive/archive_write_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  * This is a little tricky.  I used to allow the
  37  * compression handling layer to fork the compressor,
  38  * which means this write function gets invoked in
  39  * a separate process.  That would, of course, make it impossible
  40  * to actually use the data stored into memory here.
  41  * Fortunately, none of the compressors fork today and
  42  * I'm reluctant to use that route in the future but, if
  43  * forking compressors ever do reappear, this will have
  44  * to get a lot more complicated.
  45  */
  46
  47 struct write_memory_data {
  48         size_t  used;
  49         size_t  size;
  50         size_t * client_size;
  51         unsigned char * buff;
  52 };
  53
  54 static int      memory_write_close(struct archive *, void *);
  55 static int      memory_write_open(struct archive *, void *);
  56 static ssize_t  memory_write(struct archive *, void *, const void *buff, size_t);
  57
  58 /*
  59  * Client provides a pointer to a block of memory to receive
  60  * the data.  The 'size' param both tells us the size of the
  61  * client buffer and lets us tell the client the final size.
  62  */
  63 int
  64 archive_write_open_memory(struct archive *a, void *buff, size_t buffSize, size_t *used)
  65 {
  66         struct write_memory_data *mine;
  67
  68         mine = (struct write_memory_data *)malloc(sizeof(*mine));
  69         if (mine == NULL) {
  70                 archive_set_error(a, ENOMEM, "No memory");
  71                 return (ARCHIVE_FATAL);
  72         }
  73         memset(mine, 0, sizeof(*mine));
  74         mine->buff = buff;
  75         mine->size = buffSize;
  76         mine->client_size = used;
  77         return (archive_write_open(a, mine,
  78                     memory_write_open, memory_write, memory_write_close));
  79 }
  80
  81 static int
  82 memory_write_open(struct archive *a, void *client_data)
  83 {
  84         struct write_memory_data *mine;
  85         mine = client_data;
  86         mine->used = 0;
  87         if (mine->client_size != NULL)
  88                 *mine->client_size = mine->used;
  89         /* Disable padding if it hasn't been set explicitly. */
  90         if (-1 == archive_write_get_bytes_in_last_block(a))
  91                 archive_write_set_bytes_in_last_block(a, 1);
  92         return (ARCHIVE_OK);
  93 }
  94
  95 /*
  96  * Copy the data into the client buffer.
  97  * Note that we update mine->client_size on every write.
  98  * In particular, this means the client can follow exactly
  99  * how much has been written into their buffer at any time.
 100  */
 101 static ssize_t
 102 memory_write(struct archive *a, void *client_data, const void *buff, size_t length)
 103 {
 104         struct write_memory_data *mine;
 105         mine = client_data;
 106
 107         if (mine->used + length > mine->size) {
 108                 archive_set_error(a, ENOMEM, "Buffer exhausted");
 109                 return (ARCHIVE_FATAL);
 110         }
 111         memcpy(mine->buff + mine->used, buff, length);
 112         mine->used += length;
 113         if (mine->client_size != NULL)
 114                 *mine->client_size = mine->used;
 115         return (length);
 116 }
 117
 118 static int
 119 memory_write_close(struct archive *a, void *client_data)
 120 {
 121         struct write_memory_data *mine;
 122         (void)a; /* UNUSED */
 123         mine = client_data;
 124         free(mine);
 125         return (ARCHIVE_OK);
 126 }