summaryrefslogtreecommitdiff
path: root/src/base64.c
blob: c7cf034da43e5c78962baa8f670452d82c638638 (plain)
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
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
/* Base64 encode/decode strings or files.
   Copyright (C) 2004-2009 Free Software Foundation, Inc.

   This file is part of Base64.

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

   This program 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 General Public License for more details.

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

/* Written by Simon Josefsson <simon@josefsson.org>.  */

#include <config.h>

#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>

#include "system.h"
#include "error.h"
#include "xstrtol.h"
#include "quote.h"
#include "quotearg.h"

#include "base64.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "base64"

#define AUTHORS proper_name ("Simon Josefsson")

static struct option const long_options[] =
{
  {"decode", no_argument, 0, 'd'},
  {"wrap", required_argument, 0, 'w'},
  {"ignore-garbage", no_argument, 0, 'i'},

  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
             program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... [FILE]\n\
Base64 encode or decode FILE, or standard input, to standard output.\n\
\n"), program_name);
      fputs (_("\
  -w, --wrap=COLS       Wrap encoded lines after COLS character (default 76).\n\
                        Use 0 to disable line wrapping.\n\
\n\
  -d, --decode          Decode data.\n\
  -i, --ignore-garbage  When decoding, ignore non-alphabet characters.\n\
\n\
"), stdout);
      fputs (_("\
      --help            Display this help and exit.\n\
      --version         Output version information and exit.\n"), stdout);
      fputs (_("\
\n\
With no FILE, or when FILE is -, read standard input.\n"), stdout);
      fputs (_("\
\n\
The data are encoded as described for the base64 alphabet in RFC 3548.\n\
When decoding, the input may contain newlines in addition to the bytes of\n\
the formal base64 alphabet.  Use --ignore-garbage to attempt to recover\n\
from any other non-alphabet bytes in the encoded stream.\n"),
             stdout);
      emit_bug_reporting_address ();
    }

  exit (status);
}

/* Note that increasing this may decrease performance if --ignore-garbage
   is used, because of the memmove operation below. */
#define BLOCKSIZE 3072
#define B64BLOCKSIZE BASE64_LENGTH (BLOCKSIZE)

/* Ensure that BLOCKSIZE is a multiple of 3 and 4.  */
#if BLOCKSIZE % 12 != 0
# error "invalid BLOCKSIZE"
#endif

static void
wrap_write (const char *buffer, size_t len,
            uintmax_t wrap_column, size_t *current_column, FILE *out)
{
  size_t written;

  if (wrap_column == 0)
    {
      /* Simple write. */
      if (fwrite (buffer, 1, len, stdout) < len)
        error (EXIT_FAILURE, errno, _("write error"));
    }
  else
    for (written = 0; written < len;)
      {
        uintmax_t cols_remaining = wrap_column - *current_column;
        size_t to_write = MIN (cols_remaining, SIZE_MAX);
        to_write = MIN (to_write, len - written);

        if (to_write == 0)
          {
            if (fputs ("\n", out) < 0)
              error (EXIT_FAILURE, errno, _("write error"));
            *current_column = 0;
          }
        else
          {
            if (fwrite (buffer + written, 1, to_write, stdout) < to_write)
              error (EXIT_FAILURE, errno, _("write error"));
            *current_column += to_write;
            written += to_write;
          }
      }
}

static void
do_encode (FILE *in, FILE *out, uintmax_t wrap_column)
{
  size_t current_column = 0;
  char inbuf[BLOCKSIZE];
  char outbuf[B64BLOCKSIZE];
  size_t sum;

  do
    {
      size_t n;

      sum = 0;
      do
        {
          n = fread (inbuf + sum, 1, BLOCKSIZE - sum, in);
          sum += n;
        }
      while (!feof (in) && !ferror (in) && sum < BLOCKSIZE);

      if (sum > 0)
        {
          /* Process input one block at a time.  Note that BLOCKSIZE %
             3 == 0, so that no base64 pads will appear in output. */
          base64_encode (inbuf, sum, outbuf, BASE64_LENGTH (sum));

          wrap_write (outbuf, BASE64_LENGTH (sum), wrap_column,
                      &current_column, out);
        }
    }
  while (!feof (in) && !ferror (in) && sum == BLOCKSIZE);

  /* When wrapping, terminate last line. */
  if (wrap_column && current_column > 0 && fputs ("\n", out) < 0)
    error (EXIT_FAILURE, errno, _("write error"));

  if (ferror (in))
    error (EXIT_FAILURE, errno, _("read error"));
}

static void
do_decode (FILE *in, FILE *out, bool ignore_garbage)
{
  char inbuf[B64BLOCKSIZE];
  char outbuf[BLOCKSIZE];
  size_t sum;
  struct base64_decode_context ctx;

  base64_decode_ctx_init (&ctx);

  do
    {
      bool ok;
      size_t n;
      unsigned int k;

      sum = 0;
      do
        {
          n = fread (inbuf + sum, 1, B64BLOCKSIZE - sum, in);

          if (ignore_garbage)
            {
              size_t i;
              for (i = 0; n > 0 && i < n;)
                if (isbase64 (inbuf[sum + i]) || inbuf[sum + i] == '=')
                  i++;
                else
                  memmove (inbuf + sum + i, inbuf + sum + i + 1, --n - i);
            }

          sum += n;

          if (ferror (in))
            error (EXIT_FAILURE, errno, _("read error"));
        }
      while (sum < B64BLOCKSIZE && !feof (in));

      /* The following "loop" is usually iterated just once.
         However, when it processes the final input buffer, we want
         to iterate it one additional time, but with an indicator
         telling it to flush what is in CTX.  */
      for (k = 0; k < 1 + !!feof (in); k++)
        {
          if (k == 1 && ctx.i == 0)
            break;
          n = BLOCKSIZE;
          ok = base64_decode_ctx (&ctx, inbuf, (k == 0 ? sum : 0), outbuf, &n);

          if (fwrite (outbuf, 1, n, out) < n)
            error (EXIT_FAILURE, errno, _("write error"));

          if (!ok)
            error (EXIT_FAILURE, 0, _("invalid input"));
        }
    }
  while (!feof (in));
}

int
main (int argc, char **argv)
{
  int opt;
  FILE *input_fh;
  const char *infile;

  /* True if --decode has been given and we should decode data. */
  bool decode = false;
  /* True if we should ignore non-base64-alphabetic characters. */
  bool ignore_garbage = false;
  /* Wrap encoded base64 data around the 76:th column, by default. */
  uintmax_t wrap_column = 76;

  initialize_main (&argc, &argv);
  set_program_name (argv[0]);
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  while ((opt = getopt_long (argc, argv, "diw:", long_options, NULL)) != -1)
    switch (opt)
      {
      case 'd':
        decode = true;
        break;

      case 'w':
        if (xstrtoumax (optarg, NULL, 0, &wrap_column, NULL) != LONGINT_OK)
          error (EXIT_FAILURE, 0, _("invalid wrap size: %s"),
                 quotearg (optarg));
        break;

      case 'i':
        ignore_garbage = true;
        break;

        case_GETOPT_HELP_CHAR;

        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

      default:
        usage (EXIT_FAILURE);
        break;
      }

  if (argc - optind > 1)
    {
      error (0, 0, _("extra operand %s"), quote (argv[optind]));
      usage (EXIT_FAILURE);
    }

  if (optind < argc)
    infile = argv[optind];
  else
    infile = "-";

  if (STREQ (infile, "-"))
    input_fh = stdin;
  else
    {
      input_fh = fopen (infile, "r");
      if (input_fh == NULL)
        error (EXIT_FAILURE, errno, "%s", infile);
    }

  if (decode)
    do_decode (input_fh, stdout, ignore_garbage);
  else
    do_encode (input_fh, stdout, wrap_column);

  if (fclose (input_fh) == EOF)
    {
      if (STREQ (infile, "-"))
        error (EXIT_FAILURE, errno, _("closing standard input"));
      else
        error (EXIT_FAILURE, errno, "%s", infile);
    }

  exit (EXIT_SUCCESS);
}