aboutsummaryrefslogtreecommitdiff
path: root/src/util/crypto_hash_file.c
blob: e070918d34ebc722a8e79c0c3f8e6e3358e56f35 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
     This file is part of GNUnet.
     Copyright (C) 2001-2013 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later

 */
/**
 * @file util/crypto_hash_file.c
 * @brief incremental hashing of files
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include <gcrypt.h>

#define LOG(kind, ...) GNUNET_log_from (kind, "util-crypto-hash-file", \
                                        __VA_ARGS__)

#define LOG_STRERROR_FILE(kind, syscall, \
                          filename) GNUNET_log_from_strerror_file (kind, \
                                                                   "util-crypto-hash-file", \
                                                                   syscall, \
                                                                   filename)


/**
 * Context used when hashing a file.
 */
struct GNUNET_CRYPTO_FileHashContext
{
  /**
   * Function to call upon completion.
   */
  GNUNET_CRYPTO_HashCompletedCallback callback;

  /**
   * Closure for callback.
   */
  void *callback_cls;

  /**
   * IO buffer.
   */
  unsigned char *buffer;

  /**
   * Name of the file we are hashing.
   */
  char *filename;

  /**
   * File descriptor.
   */
  struct GNUNET_DISK_FileHandle *fh;

  /**
   * Cummulated hash.
   */
  gcry_md_hd_t md;

  /**
   * Size of the file.
   */
  uint64_t fsize;

  /**
   * Current offset.
   */
  uint64_t offset;

  /**
   * Current task for hashing.
   */
  struct GNUNET_SCHEDULER_Task *task;

  /**
   * Priority we use.
   */
  enum GNUNET_SCHEDULER_Priority priority;

  /**
   * Blocksize.
   */
  size_t bsize;
};


/**
 * Report result of hash computation to callback
 * and free associated resources.
 */
static void
file_hash_finish (struct GNUNET_CRYPTO_FileHashContext *fhc,
                  const struct GNUNET_HashCode *res)
{
  fhc->callback (fhc->callback_cls, res);
  GNUNET_free (fhc->filename);
  if (! GNUNET_DISK_handle_invalid (fhc->fh))
    GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
  gcry_md_close (fhc->md);
  GNUNET_free (fhc);             /* also frees fhc->buffer */
}


/**
 * File hashing task.
 *
 * @param cls closure
 */
static void
file_hash_task (void *cls)
{
  struct GNUNET_CRYPTO_FileHashContext *fhc = cls;
  struct GNUNET_HashCode *res;
  size_t delta;
  ssize_t sret;

  fhc->task = NULL;
  GNUNET_assert (fhc->offset <= fhc->fsize);
  delta = fhc->bsize;
  if (fhc->fsize - fhc->offset < delta)
    delta = fhc->fsize - fhc->offset;
  sret = GNUNET_DISK_file_read (fhc->fh,
                                fhc->buffer,
                                delta);
  if ((sret < 0) ||
      (delta != (size_t) sret))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "read",
                       fhc->filename);
    file_hash_finish (fhc,
                      NULL);
    return;
  }
  gcry_md_write (fhc->md,
                 fhc->buffer,
                 delta);
  fhc->offset += delta;
  if (fhc->offset == fhc->fsize)
  {
    res = (struct GNUNET_HashCode *) gcry_md_read (fhc->md,
                                                   GCRY_MD_SHA512);
    file_hash_finish (fhc, res);
    return;
  }
  fhc->task = GNUNET_SCHEDULER_add_with_priority (fhc->priority,
                                                  &file_hash_task,
                                                  fhc);
}


/**
 * Compute the hash of an entire file.
 *
 * @param priority scheduling priority to use
 * @param filename name of file to hash
 * @param blocksize number of bytes to process in one task
 * @param callback function to call upon completion
 * @param callback_cls closure for @a callback
 * @return NULL on (immediate) errror
 */
struct GNUNET_CRYPTO_FileHashContext *
GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
                         const char *filename,
                         size_t blocksize,
                         GNUNET_CRYPTO_HashCompletedCallback callback,
                         void *callback_cls)
{
  struct GNUNET_CRYPTO_FileHashContext *fhc;

  GNUNET_assert (blocksize > 0);
  fhc =
    GNUNET_malloc (sizeof(struct GNUNET_CRYPTO_FileHashContext) + blocksize);
  fhc->callback = callback;
  fhc->callback_cls = callback_cls;
  fhc->buffer = (unsigned char *) &fhc[1];
  fhc->filename = GNUNET_strdup (filename);
  if (GPG_ERR_NO_ERROR != gcry_md_open (&fhc->md, GCRY_MD_SHA512, 0))
  {
    GNUNET_break (0);
    GNUNET_free (fhc);
    return NULL;
  }
  fhc->bsize = blocksize;
  if (GNUNET_OK !=
      GNUNET_DISK_file_size (filename,
                             &fhc->fsize,
                             GNUNET_NO,
                             GNUNET_YES))
  {
    GNUNET_free (fhc->filename);
    GNUNET_free (fhc);
    return NULL;
  }
  fhc->fh = GNUNET_DISK_file_open (filename,
                                   GNUNET_DISK_OPEN_READ,
                                   GNUNET_DISK_PERM_NONE);
  if (! fhc->fh)
  {
    GNUNET_free (fhc->filename);
    GNUNET_free (fhc);
    return NULL;
  }
  fhc->priority = priority;
  fhc->task = GNUNET_SCHEDULER_add_with_priority (priority,
                                                  &file_hash_task,
                                                  fhc);
  return fhc;
}


/**
 * Cancel a file hashing operation.
 *
 * @param fhc operation to cancel (callback must not yet have been invoked)
 */
void
GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc)
{
  GNUNET_SCHEDULER_cancel (fhc->task);
  GNUNET_free (fhc->filename);
  GNUNET_break (GNUNET_OK ==
                GNUNET_DISK_file_close (fhc->fh));
  GNUNET_free (fhc);
}


/* end of crypto_hash_file.c */