source4/lib/util/data_blob.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Easy management of byte-length data
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Andrew Bartlett 2001
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 /**
  24  * @file
  25  * @brief Manipulation of arbitrary data blobs
  26  **/
  27
  28 /**
  29  construct a data blob, must be freed with data_blob_free()
  30  you can pass NULL for p and get a blank data blob
  31 **/
  32 _PUBLIC_ DATA_BLOB data_blob_named(const void *p, size_t length, const char *name)
  33 {
  34         DATA_BLOB ret;
  35
  36         if (p == NULL && length == 0) {
  37                 ZERO_STRUCT(ret);
  38                 return ret;
  39         }
  40
  41         if (p) {
  42                 ret.data = (uint8_t *)talloc_memdup(NULL, p, length);
  43         } else {
  44                 ret.data = talloc_array(NULL, uint8_t, length);
  45         }
  46         if (ret.data == NULL) {
  47                 ret.length = 0;
  48                 return ret;
  49         }
  50         talloc_set_name_const(ret.data, name);
  51         ret.length = length;
  52         return ret;
  53 }
  54
  55 /**
  56  construct a data blob, using supplied TALLOC_CTX
  57 **/
  58 _PUBLIC_ DATA_BLOB data_blob_talloc_named(TALLOC_CTX *mem_ctx, const void *p, size_t length, const char *name)
  59 {
  60         DATA_BLOB ret = data_blob_named(p, length, name);
  61
  62         if (ret.data) {
  63                 talloc_steal(mem_ctx, ret.data);
  64         }
  65         return ret;
  66 }
  67
  68
  69 /**
  70  reference a data blob, to the supplied TALLOC_CTX.
  71  Returns a NULL DATA_BLOB on failure
  72 **/
  73 _PUBLIC_ DATA_BLOB data_blob_talloc_reference(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
  74 {
  75         DATA_BLOB ret = *blob;
  76
  77         ret.data = talloc_reference(mem_ctx, blob->data);
  78
  79         if (!ret.data) {
  80                 return data_blob(NULL, 0);
  81         }
  82         return ret;
  83 }
  84
  85 /**
  86  construct a zero data blob, using supplied TALLOC_CTX.
  87  use this sparingly as it initialises data - better to initialise
  88  yourself if you want specific data in the blob
  89 **/
  90 _PUBLIC_ DATA_BLOB data_blob_talloc_zero(TALLOC_CTX *mem_ctx, size_t length)
  91 {
  92         DATA_BLOB blob = data_blob_talloc(mem_ctx, NULL, length);
  93         data_blob_clear(&blob);
  94         return blob;
  95 }
  96
  97 /**
  98 free a data blob
  99 **/
 100 _PUBLIC_ void data_blob_free(DATA_BLOB *d)
 101 {
 102         if (d) {
 103                 talloc_free(d->data);
 104                 d->data = NULL;
 105                 d->length = 0;
 106         }
 107 }
 108
 109 /**
 110 clear a DATA_BLOB's contents
 111 **/
 112 _PUBLIC_ void data_blob_clear(DATA_BLOB *d)
 113 {
 114         if (d->data) {
 115                 memset(d->data, 0, d->length);
 116         }
 117 }
 118
 119 /**
 120 free a data blob and clear its contents
 121 **/
 122 _PUBLIC_ void data_blob_clear_free(DATA_BLOB *d)
 123 {
 124         data_blob_clear(d);
 125         data_blob_free(d);
 126 }
 127
 128
 129 /**
 130 check if two data blobs are equal
 131 **/
 132 _PUBLIC_ int data_blob_cmp(const DATA_BLOB *d1, const DATA_BLOB *d2)
 133 {
 134         int ret;
 135         if (d1->data == NULL && d2->data != NULL) {
 136                 return -1;
 137         }
 138         if (d1->data != NULL && d2->data == NULL) {
 139                 return 1;
 140         }
 141         if (d1->data == d2->data) {
 142                 return d1->length - d2->length;
 143         }
 144         ret = memcmp(d1->data, d2->data, MIN(d1->length, d2->length));
 145         if (ret == 0) {
 146                 return d1->length - d2->length;
 147         }
 148         return ret;
 149 }
 150
 151 /**
 152 print the data_blob as hex string
 153 **/
 154 _PUBLIC_ char *data_blob_hex_string(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob)
 155 {
 156         int i;
 157         char *hex_string;
 158
 159         hex_string = talloc_array(mem_ctx, char, (blob->length*2)+1);
 160         if (!hex_string) {
 161                 return NULL;
 162         }
 163
 164         for (i = 0; i < blob->length; i++)
 165                 slprintf(&hex_string[i*2], 3, "%02X", blob->data[i]);
 166
 167         hex_string[(blob->length*2)] = '\0';
 168         return hex_string;
 169 }
 170
 171 /**
 172   useful for constructing data blobs in test suites, while
 173   avoiding const warnings
 174 **/
 175 _PUBLIC_ DATA_BLOB data_blob_string_const(const char *str)
 176 {
 177         DATA_BLOB blob;
 178         blob.data = discard_const_p(uint8_t, str);
 179         blob.length = str ? strlen(str) : 0;
 180         return blob;
 181 }
 182
 183 /**
 184  * Create a new data blob from const data
 185  */
 186
 187 _PUBLIC_ DATA_BLOB data_blob_const(const void *p, size_t length)
 188 {
 189         DATA_BLOB blob;
 190         blob.data = discard_const_p(uint8_t, p);
 191         blob.length = length;
 192         return blob;
 193 }
 194
 195
 196 /**
 197   realloc a data_blob
 198 **/
 199 _PUBLIC_ bool data_blob_realloc(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, size_t length)
 200 {
 201         blob->data = talloc_realloc(mem_ctx, blob->data, uint8_t, length);
 202         if (blob->data == NULL)
 203                 return false;
 204         blob->length = length;
 205         return true;
 206 }
 207
 208
 209 /**
 210   append some data to a data blob
 211 **/
 212 _PUBLIC_ bool data_blob_append(TALLOC_CTX *mem_ctx, DATA_BLOB *blob,
 213                                    const void *p, size_t length)
 214 {
 215         size_t old_len = blob->length;
 216         size_t new_len = old_len + length;
 217         if (new_len < length || new_len < old_len) {
 218                 return false;
 219         }
 220
 221         if ((const uint8_t *)p + length < (const uint8_t *)p) {
 222                 return false;
 223         }
 224
 225         if (!data_blob_realloc(mem_ctx, blob, new_len)) {
 226                 return false;
 227         }
 228
 229         memcpy(blob->data + old_len, p, length);
 230         return true;
 231 }
 232