src/base64.c

   1 /* Base64 encode/decode strings or files.
   2    Copyright (C) 2004-2016 Free Software Foundation, Inc.
   3
   4    This file is part of Base64.
   5
   6    This program is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation, either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
  18
  19 /* Written by Simon Josefsson <simon@josefsson.org>.  */
  20
  21 #include <config.h>
  22
  23 #include <stdio.h>
  24 #include <getopt.h>
  25 #include <sys/types.h>
  26
  27 #include "system.h"
  28 #include "error.h"
  29 #include "fadvise.h"
  30 #include "quote.h"
  31 #include "xstrtol.h"
  32 #include "xdectoint.h"
  33 #include "xfreopen.h"
  34
  35 #define AUTHORS proper_name ("Simon Josefsson")
  36
  37 #if BASE_TYPE == 32
  38 # include "base32.h"
  39 # define PROGRAM_NAME "base32"
  40 #else
  41 # include "base64.h"
  42 # define PROGRAM_NAME "base64"
  43 #endif
  44
  45
  46 static struct option const long_options[] =
  47 {
  48   {"decode", no_argument, 0, 'd'},
  49   {"wrap", required_argument, 0, 'w'},
  50   {"ignore-garbage", no_argument, 0, 'i'},
  51
  52   {GETOPT_HELP_OPTION_DECL},
  53   {GETOPT_VERSION_OPTION_DECL},
  54   {NULL, 0, NULL, 0}
  55 };
  56
  57 void
  58 usage (int status)
  59 {
  60   if (status != EXIT_SUCCESS)
  61     emit_try_help ();
  62   else
  63     {
  64       printf (_("\
  65 Usage: %s [OPTION]... [FILE]\n\
  66 Base%d encode or decode FILE, or standard input, to standard output.\n\
  67 "), program_name, BASE_TYPE);
  68
  69       emit_stdin_note ();
  70       emit_mandatory_arg_note ();
  71
  72       fputs (_("\
  73   -d, --decode          decode data\n\
  74   -i, --ignore-garbage  when decoding, ignore non-alphabet characters\n\
  75   -w, --wrap=COLS       wrap encoded lines after COLS character (default 76).\n\
  76                           Use 0 to disable line wrapping\n\
  77 \n\
  78 "), stdout);
  79       fputs (HELP_OPTION_DESCRIPTION, stdout);
  80       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  81       printf (_("\
  82 \n\
  83 The data are encoded as described for the %s alphabet in RFC 4648.\n\
  84 When decoding, the input may contain newlines in addition to the bytes of\n\
  85 the formal %s alphabet.  Use --ignore-garbage to attempt to recover\n\
  86 from any other non-alphabet bytes in the encoded stream.\n"),
  87               PROGRAM_NAME, PROGRAM_NAME);
  88       emit_ancillary_info (PROGRAM_NAME);
  89     }
  90
  91   exit (status);
  92 }
  93
  94 #define ENC_BLOCKSIZE (1024*3*10)
  95
  96 #if BASE_TYPE == 32
  97 # define BASE_LENGTH BASE32_LENGTH
  98 /* Note that increasing this may decrease performance if --ignore-garbage
  99    is used, because of the memmove operation below.  */
 100 # define DEC_BLOCKSIZE (1024*5)
 101
 102 /* Ensure that BLOCKSIZE is a multiple of 5 and 8.  */
 103 verify (ENC_BLOCKSIZE % 40 == 0);  /* So padding chars only on last block.  */
 104 verify (DEC_BLOCKSIZE % 40 == 0);  /* So complete encoded blocks are used.  */
 105
 106 # define base_encode base32_encode
 107 # define base_decode_context base32_decode_context
 108 # define base_decode_ctx_init base32_decode_ctx_init
 109 # define base_decode_ctx base32_decode_ctx
 110 # define isbase isbase32
 111 #else
 112 # define BASE_LENGTH BASE64_LENGTH
 113 /* Note that increasing this may decrease performance if --ignore-garbage
 114    is used, because of the memmove operation below.  */
 115 # define DEC_BLOCKSIZE (1024*3)
 116
 117 /* Ensure that BLOCKSIZE is a multiple of 3 and 4.  */
 118 verify (ENC_BLOCKSIZE % 12 == 0);  /* So padding chars only on last block.  */
 119 verify (DEC_BLOCKSIZE % 12 == 0);  /* So complete encoded blocks are used.  */
 120
 121 # define base_encode base64_encode
 122 # define base_decode_context base64_decode_context
 123 # define base_decode_ctx_init base64_decode_ctx_init
 124 # define base_decode_ctx base64_decode_ctx
 125 # define isbase isbase64
 126 #endif
 127
 128 static void
 129 wrap_write (const char *buffer, size_t len,
 130             uintmax_t wrap_column, size_t *current_column, FILE *out)
 131 {
 132   size_t written;
 133
 134   if (wrap_column == 0)
 135     {
 136       /* Simple write. */
 137       if (fwrite (buffer, 1, len, stdout) < len)
 138         error (EXIT_FAILURE, errno, _("write error"));
 139     }
 140   else
 141     for (written = 0; written < len;)
 142       {
 143         uintmax_t cols_remaining = wrap_column - *current_column;
 144         size_t to_write = MIN (cols_remaining, SIZE_MAX);
 145         to_write = MIN (to_write, len - written);
 146
 147         if (to_write == 0)
 148           {
 149             if (fputc ('\n', out) == EOF)
 150               error (EXIT_FAILURE, errno, _("write error"));
 151             *current_column = 0;
 152           }
 153         else
 154           {
 155             if (fwrite (buffer + written, 1, to_write, stdout) < to_write)
 156               error (EXIT_FAILURE, errno, _("write error"));
 157             *current_column += to_write;
 158             written += to_write;
 159           }
 160       }
 161 }
 162
 163 static void
 164 do_encode (FILE *in, FILE *out, uintmax_t wrap_column)
 165 {
 166   size_t current_column = 0;
 167   char inbuf[ENC_BLOCKSIZE];
 168   char outbuf[BASE_LENGTH (ENC_BLOCKSIZE)];
 169   size_t sum;
 170
 171   do
 172     {
 173       size_t n;
 174
 175       sum = 0;
 176       do
 177         {
 178           n = fread (inbuf + sum, 1, ENC_BLOCKSIZE - sum, in);
 179           sum += n;
 180         }
 181       while (!feof (in) && !ferror (in) && sum < ENC_BLOCKSIZE);
 182
 183       if (sum > 0)
 184         {
 185           /* Process input one block at a time.  Note that ENC_BLOCKSIZE
 186              is sized so that no pad chars will appear in output. */
 187           base_encode (inbuf, sum, outbuf, BASE_LENGTH (sum));
 188
 189           wrap_write (outbuf, BASE_LENGTH (sum), wrap_column,
 190                       &current_column, out);
 191         }
 192     }
 193   while (!feof (in) && !ferror (in) && sum == ENC_BLOCKSIZE);
 194
 195   /* When wrapping, terminate last line. */
 196   if (wrap_column && current_column > 0 && fputc ('\n', out) == EOF)
 197     error (EXIT_FAILURE, errno, _("write error"));
 198
 199   if (ferror (in))
 200     error (EXIT_FAILURE, errno, _("read error"));
 201 }
 202
 203 static void
 204 do_decode (FILE *in, FILE *out, bool ignore_garbage)
 205 {
 206   char inbuf[BASE_LENGTH (DEC_BLOCKSIZE)];
 207   char outbuf[DEC_BLOCKSIZE];
 208   size_t sum;
 209   struct base_decode_context ctx;
 210
 211   base_decode_ctx_init (&ctx);
 212
 213   do
 214     {
 215       bool ok;
 216       size_t n;
 217       unsigned int k;
 218
 219       sum = 0;
 220       do
 221         {
 222           n = fread (inbuf + sum, 1, BASE_LENGTH (DEC_BLOCKSIZE) - sum, in);
 223
 224           if (ignore_garbage)
 225             {
 226               size_t i;
 227               for (i = 0; n > 0 && i < n;)
 228                 if (isbase (inbuf[sum + i]) || inbuf[sum + i] == '=')
 229                   i++;
 230                 else
 231                   memmove (inbuf + sum + i, inbuf + sum + i + 1, --n - i);
 232             }
 233
 234           sum += n;
 235
 236           if (ferror (in))
 237             error (EXIT_FAILURE, errno, _("read error"));
 238         }
 239       while (sum < BASE_LENGTH (DEC_BLOCKSIZE) && !feof (in));
 240
 241       /* The following "loop" is usually iterated just once.
 242          However, when it processes the final input buffer, we want
 243          to iterate it one additional time, but with an indicator
 244          telling it to flush what is in CTX.  */
 245       for (k = 0; k < 1 + !!feof (in); k++)
 246         {
 247           if (k == 1 && ctx.i == 0)
 248             break;
 249           n = DEC_BLOCKSIZE;
 250           ok = base_decode_ctx (&ctx, inbuf, (k == 0 ? sum : 0), outbuf, &n);
 251
 252           if (fwrite (outbuf, 1, n, out) < n)
 253             error (EXIT_FAILURE, errno, _("write error"));
 254
 255           if (!ok)
 256             error (EXIT_FAILURE, 0, _("invalid input"));
 257         }
 258     }
 259   while (!feof (in));
 260 }
 261
 262 int
 263 main (int argc, char **argv)
 264 {
 265   int opt;
 266   FILE *input_fh;
 267   const char *infile;
 268
 269   /* True if --decode has been given and we should decode data. */
 270   bool decode = false;
 271   /* True if we should ignore non-base-alphabetic characters. */
 272   bool ignore_garbage = false;
 273   /* Wrap encoded data around the 76:th column, by default. */
 274   uintmax_t wrap_column = 76;
 275
 276   initialize_main (&argc, &argv);
 277   set_program_name (argv[0]);
 278   setlocale (LC_ALL, "");
 279   bindtextdomain (PACKAGE, LOCALEDIR);
 280   textdomain (PACKAGE);
 281
 282   atexit (close_stdout);
 283
 284   while ((opt = getopt_long (argc, argv, "diw:", long_options, NULL)) != -1)
 285     switch (opt)
 286       {
 287       case 'd':
 288         decode = true;
 289         break;
 290
 291       case 'w':
 292         wrap_column = xdectoumax (optarg, 0, UINTMAX_MAX, "",
 293                                   _("invalid wrap size"), 0);
 294         break;
 295
 296       case 'i':
 297         ignore_garbage = true;
 298         break;
 299
 300       case_GETOPT_HELP_CHAR;
 301
 302       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 303
 304       default:
 305         usage (EXIT_FAILURE);
 306         break;
 307       }
 308
 309   if (argc - optind > 1)
 310     {
 311       error (0, 0, _("extra operand %s"), quote (argv[optind]));
 312       usage (EXIT_FAILURE);
 313     }
 314
 315   if (optind < argc)
 316     infile = argv[optind];
 317   else
 318     infile = "-";
 319
 320   if (STREQ (infile, "-"))
 321     {
 322       if (O_BINARY)
 323         xfreopen (NULL, "rb", stdin);
 324       input_fh = stdin;
 325     }
 326   else
 327     {
 328       input_fh = fopen (infile, "rb");
 329       if (input_fh == NULL)
 330         error (EXIT_FAILURE, errno, "%s", quotef (infile));
 331     }
 332
 333   fadvise (input_fh, FADVISE_SEQUENTIAL);
 334
 335   if (decode)
 336     do_decode (input_fh, stdout, ignore_garbage);
 337   else
 338     do_encode (input_fh, stdout, wrap_column);
 339
 340   if (fclose (input_fh) == EOF)
 341     {
 342       if (STREQ (infile, "-"))
 343         error (EXIT_FAILURE, errno, _("closing standard input"));
 344       else
 345         error (EXIT_FAILURE, errno, "%s", quotef (infile));
 346     }
 347
 348   return EXIT_SUCCESS;
 349 }