src/basic/hexdecoct.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <ctype.h>
   4 #include <errno.h>
   5 #include <stdint.h>
   6 #include <stdlib.h>
   7
   8 #include "alloc-util.h"
   9 #include "hexdecoct.h"
  10 #include "macro.h"
  11 #include "string-util.h"
  12 #include "util.h"
  13
  14 char octchar(int x) {
  15         return '0' + (x & 7);
  16 }
  17
  18 int unoctchar(char c) {
  19
  20         if (c >= '0' && c <= '7')
  21                 return c - '0';
  22
  23         return -EINVAL;
  24 }
  25
  26 char decchar(int x) {
  27         return '0' + (x % 10);
  28 }
  29
  30 int undecchar(char c) {
  31
  32         if (c >= '0' && c <= '9')
  33                 return c - '0';
  34
  35         return -EINVAL;
  36 }
  37
  38 char hexchar(int x) {
  39         static const char table[16] = "0123456789abcdef";
  40
  41         return table[x & 15];
  42 }
  43
  44 int unhexchar(char c) {
  45
  46         if (c >= '0' && c <= '9')
  47                 return c - '0';
  48
  49         if (c >= 'a' && c <= 'f')
  50                 return c - 'a' + 10;
  51
  52         if (c >= 'A' && c <= 'F')
  53                 return c - 'A' + 10;
  54
  55         return -EINVAL;
  56 }
  57
  58 char *hexmem(const void *p, size_t l) {
  59         const uint8_t *x;
  60         char *r, *z;
  61
  62         z = r = new(char, l * 2 + 1);
  63         if (!r)
  64                 return NULL;
  65
  66         for (x = p; x < (const uint8_t*) p + l; x++) {
  67                 *(z++) = hexchar(*x >> 4);
  68                 *(z++) = hexchar(*x & 15);
  69         }
  70
  71         *z = 0;
  72         return r;
  73 }
  74
  75 static int unhex_next(const char **p, size_t *l) {
  76         int r;
  77
  78         assert(p);
  79         assert(l);
  80
  81         /* Find the next non-whitespace character, and decode it. We
  82          * greedily skip all preceding and all following whitespace. */
  83
  84         for (;;) {
  85                 if (*l == 0)
  86                         return -EPIPE;
  87
  88                 if (!strchr(WHITESPACE, **p))
  89                         break;
  90
  91                 /* Skip leading whitespace */
  92                 (*p)++, (*l)--;
  93         }
  94
  95         r = unhexchar(**p);
  96         if (r < 0)
  97                 return r;
  98
  99         for (;;) {
 100                 (*p)++, (*l)--;
 101
 102                 if (*l == 0 || !strchr(WHITESPACE, **p))
 103                         break;
 104
 105                 /* Skip following whitespace */
 106         }
 107
 108         return r;
 109 }
 110
 111 int unhexmem(const char *p, size_t l, void **ret, size_t *ret_len) {
 112         _cleanup_free_ uint8_t *buf = NULL;
 113         const char *x;
 114         uint8_t *z;
 115
 116         assert(ret);
 117         assert(ret_len);
 118         assert(p || l == 0);
 119
 120         if (l == (size_t) -1)
 121                 l = strlen(p);
 122
 123         /* Note that the calculation of memory size is an upper boundary, as we ignore whitespace while decoding */
 124         buf = malloc((l + 1) / 2 + 1);
 125         if (!buf)
 126                 return -ENOMEM;
 127
 128         for (x = p, z = buf;;) {
 129                 int a, b;
 130
 131                 a = unhex_next(&x, &l);
 132                 if (a == -EPIPE) /* End of string */
 133                         break;
 134                 if (a < 0)
 135                         return a;
 136
 137                 b = unhex_next(&x, &l);
 138                 if (b < 0)
 139                         return b;
 140
 141                 *(z++) = (uint8_t) a << 4 | (uint8_t) b;
 142         }
 143
 144         *z = 0;
 145
 146         *ret_len = (size_t) (z - buf);
 147         *ret = TAKE_PTR(buf);
 148
 149         return 0;
 150 }
 151
 152 /* https://tools.ietf.org/html/rfc4648#section-6
 153  * Notice that base32hex differs from base32 in the alphabet it uses.
 154  * The distinction is that the base32hex representation preserves the
 155  * order of the underlying data when compared as bytestrings, this is
 156  * useful when representing NSEC3 hashes, as one can then verify the
 157  * order of hashes directly from their representation. */
 158 char base32hexchar(int x) {
 159         static const char table[32] = "0123456789"
 160                                       "ABCDEFGHIJKLMNOPQRSTUV";
 161
 162         return table[x & 31];
 163 }
 164
 165 int unbase32hexchar(char c) {
 166         unsigned offset;
 167
 168         if (c >= '0' && c <= '9')
 169                 return c - '0';
 170
 171         offset = '9' - '0' + 1;
 172
 173         if (c >= 'A' && c <= 'V')
 174                 return c - 'A' + offset;
 175
 176         return -EINVAL;
 177 }
 178
 179 char *base32hexmem(const void *p, size_t l, bool padding) {
 180         char *r, *z;
 181         const uint8_t *x;
 182         size_t len;
 183
 184         assert(p || l == 0);
 185
 186         if (padding)
 187                 /* five input bytes makes eight output bytes, padding is added so we must round up */
 188                 len = 8 * (l + 4) / 5;
 189         else {
 190                 /* same, but round down as there is no padding */
 191                 len = 8 * l / 5;
 192
 193                 switch (l % 5) {
 194                 case 4:
 195                         len += 7;
 196                         break;
 197                 case 3:
 198                         len += 5;
 199                         break;
 200                 case 2:
 201                         len += 4;
 202                         break;
 203                 case 1:
 204                         len += 2;
 205                         break;
 206                 }
 207         }
 208
 209         z = r = malloc(len + 1);
 210         if (!r)
 211                 return NULL;
 212
 213         for (x = p; x < (const uint8_t*) p + (l / 5) * 5; x += 5) {
 214                 /* x[0] == XXXXXXXX; x[1] == YYYYYYYY; x[2] == ZZZZZZZZ
 215                  * x[3] == QQQQQQQQ; x[4] == WWWWWWWW */
 216                 *(z++) = base32hexchar(x[0] >> 3);                    /* 000XXXXX */
 217                 *(z++) = base32hexchar((x[0] & 7) << 2 | x[1] >> 6);  /* 000XXXYY */
 218                 *(z++) = base32hexchar((x[1] & 63) >> 1);             /* 000YYYYY */
 219                 *(z++) = base32hexchar((x[1] & 1) << 4 | x[2] >> 4);  /* 000YZZZZ */
 220                 *(z++) = base32hexchar((x[2] & 15) << 1 | x[3] >> 7); /* 000ZZZZQ */
 221                 *(z++) = base32hexchar((x[3] & 127) >> 2);            /* 000QQQQQ */
 222                 *(z++) = base32hexchar((x[3] & 3) << 3 | x[4] >> 5);  /* 000QQWWW */
 223                 *(z++) = base32hexchar((x[4] & 31));                  /* 000WWWWW */
 224         }
 225
 226         switch (l % 5) {
 227         case 4:
 228                 *(z++) = base32hexchar(x[0] >> 3);                    /* 000XXXXX */
 229                 *(z++) = base32hexchar((x[0] & 7) << 2 | x[1] >> 6);  /* 000XXXYY */
 230                 *(z++) = base32hexchar((x[1] & 63) >> 1);             /* 000YYYYY */
 231                 *(z++) = base32hexchar((x[1] & 1) << 4 | x[2] >> 4);   /* 000YZZZZ */
 232                 *(z++) = base32hexchar((x[2] & 15) << 1 | x[3] >> 7); /* 000ZZZZQ */
 233                 *(z++) = base32hexchar((x[3] & 127) >> 2);            /* 000QQQQQ */
 234                 *(z++) = base32hexchar((x[3] & 3) << 3);              /* 000QQ000 */
 235                 if (padding)
 236                         *(z++) = '=';
 237
 238                 break;
 239
 240         case 3:
 241                 *(z++) = base32hexchar(x[0] >> 3);                   /* 000XXXXX */
 242                 *(z++) = base32hexchar((x[0] & 7) << 2 | x[1] >> 6); /* 000XXXYY */
 243                 *(z++) = base32hexchar((x[1] & 63) >> 1);            /* 000YYYYY */
 244                 *(z++) = base32hexchar((x[1] & 1) << 4 | x[2] >> 4); /* 000YZZZZ */
 245                 *(z++) = base32hexchar((x[2] & 15) << 1);            /* 000ZZZZ0 */
 246                 if (padding) {
 247                         *(z++) = '=';
 248                         *(z++) = '=';
 249                         *(z++) = '=';
 250                 }
 251
 252                 break;
 253
 254         case 2:
 255                 *(z++) = base32hexchar(x[0] >> 3);                   /* 000XXXXX */
 256                 *(z++) = base32hexchar((x[0] & 7) << 2 | x[1] >> 6); /* 000XXXYY */
 257                 *(z++) = base32hexchar((x[1] & 63) >> 1);            /* 000YYYYY */
 258                 *(z++) = base32hexchar((x[1] & 1) << 4);             /* 000Y0000 */
 259                 if (padding) {
 260                         *(z++) = '=';
 261                         *(z++) = '=';
 262                         *(z++) = '=';
 263                         *(z++) = '=';
 264                 }
 265
 266                 break;
 267
 268         case 1:
 269                 *(z++) = base32hexchar(x[0] >> 3);       /* 000XXXXX */
 270                 *(z++) = base32hexchar((x[0] & 7) << 2); /* 000XXX00 */
 271                 if (padding) {
 272                         *(z++) = '=';
 273                         *(z++) = '=';
 274                         *(z++) = '=';
 275                         *(z++) = '=';
 276                         *(z++) = '=';
 277                         *(z++) = '=';
 278                 }
 279
 280                 break;
 281         }
 282
 283         *z = 0;
 284         return r;
 285 }
 286
 287 int unbase32hexmem(const char *p, size_t l, bool padding, void **mem, size_t *_len) {
 288         _cleanup_free_ uint8_t *r = NULL;
 289         int a, b, c, d, e, f, g, h;
 290         uint8_t *z;
 291         const char *x;
 292         size_t len;
 293         unsigned pad = 0;
 294
 295         assert(p || l == 0);
 296         assert(mem);
 297         assert(_len);
 298
 299         if (l == (size_t) -1)
 300                 l = strlen(p);
 301
 302         /* padding ensures any base32hex input has input divisible by 8 */
 303         if (padding && l % 8 != 0)
 304                 return -EINVAL;
 305
 306         if (padding) {
 307                 /* strip the padding */
 308                 while (l > 0 && p[l - 1] == '=' && pad < 7) {
 309                         pad++;
 310                         l--;
 311                 }
 312         }
 313
 314         /* a group of eight input bytes needs five output bytes, in case of
 315          * padding we need to add some extra bytes */
 316         len = (l / 8) * 5;
 317
 318         switch (l % 8) {
 319         case 7:
 320                 len += 4;
 321                 break;
 322         case 5:
 323                 len += 3;
 324                 break;
 325         case 4:
 326                 len += 2;
 327                 break;
 328         case 2:
 329                 len += 1;
 330                 break;
 331         case 0:
 332                 break;
 333         default:
 334                 return -EINVAL;
 335         }
 336
 337         z = r = malloc(len + 1);
 338         if (!r)
 339                 return -ENOMEM;
 340
 341         for (x = p; x < p + (l / 8) * 8; x += 8) {
 342                 /* a == 000XXXXX; b == 000YYYYY; c == 000ZZZZZ; d == 000WWWWW
 343                  * e == 000SSSSS; f == 000QQQQQ; g == 000VVVVV; h == 000RRRRR */
 344                 a = unbase32hexchar(x[0]);
 345                 if (a < 0)
 346                         return -EINVAL;
 347
 348                 b = unbase32hexchar(x[1]);
 349                 if (b < 0)
 350                         return -EINVAL;
 351
 352                 c = unbase32hexchar(x[2]);
 353                 if (c < 0)
 354                         return -EINVAL;
 355
 356                 d = unbase32hexchar(x[3]);
 357                 if (d < 0)
 358                         return -EINVAL;
 359
 360                 e = unbase32hexchar(x[4]);
 361                 if (e < 0)
 362                         return -EINVAL;
 363
 364                 f = unbase32hexchar(x[5]);
 365                 if (f < 0)
 366                         return -EINVAL;
 367
 368                 g = unbase32hexchar(x[6]);
 369                 if (g < 0)
 370                         return -EINVAL;
 371
 372                 h = unbase32hexchar(x[7]);
 373                 if (h < 0)
 374                         return -EINVAL;
 375
 376                 *(z++) = (uint8_t) a << 3 | (uint8_t) b >> 2;                    /* XXXXXYYY */
 377                 *(z++) = (uint8_t) b << 6 | (uint8_t) c << 1 | (uint8_t) d >> 4; /* YYZZZZZW */
 378                 *(z++) = (uint8_t) d << 4 | (uint8_t) e >> 1;                    /* WWWWSSSS */
 379                 *(z++) = (uint8_t) e << 7 | (uint8_t) f << 2 | (uint8_t) g >> 3; /* SQQQQQVV */
 380                 *(z++) = (uint8_t) g << 5 | (uint8_t) h;                         /* VVVRRRRR */
 381         }
 382
 383         switch (l % 8) {
 384         case 7:
 385                 a = unbase32hexchar(x[0]);
 386                 if (a < 0)
 387                         return -EINVAL;
 388
 389                 b = unbase32hexchar(x[1]);
 390                 if (b < 0)
 391                         return -EINVAL;
 392
 393                 c = unbase32hexchar(x[2]);
 394                 if (c < 0)
 395                         return -EINVAL;
 396
 397                 d = unbase32hexchar(x[3]);
 398                 if (d < 0)
 399                         return -EINVAL;
 400
 401                 e = unbase32hexchar(x[4]);
 402                 if (e < 0)
 403                         return -EINVAL;
 404
 405                 f = unbase32hexchar(x[5]);
 406                 if (f < 0)
 407                         return -EINVAL;
 408
 409                 g = unbase32hexchar(x[6]);
 410                 if (g < 0)
 411                         return -EINVAL;
 412
 413                 /* g == 000VV000 */
 414                 if (g & 7)
 415                         return -EINVAL;
 416
 417                 *(z++) = (uint8_t) a << 3 | (uint8_t) b >> 2;                    /* XXXXXYYY */
 418                 *(z++) = (uint8_t) b << 6 | (uint8_t) c << 1 | (uint8_t) d >> 4; /* YYZZZZZW */
 419                 *(z++) = (uint8_t) d << 4 | (uint8_t) e >> 1;                    /* WWWWSSSS */
 420                 *(z++) = (uint8_t) e << 7 | (uint8_t) f << 2 | (uint8_t) g >> 3; /* SQQQQQVV */
 421
 422                 break;
 423         case 5:
 424                 a = unbase32hexchar(x[0]);
 425                 if (a < 0)
 426                         return -EINVAL;
 427
 428                 b = unbase32hexchar(x[1]);
 429                 if (b < 0)
 430                         return -EINVAL;
 431
 432                 c = unbase32hexchar(x[2]);
 433                 if (c < 0)
 434                         return -EINVAL;
 435
 436                 d = unbase32hexchar(x[3]);
 437                 if (d < 0)
 438                         return -EINVAL;
 439
 440                 e = unbase32hexchar(x[4]);
 441                 if (e < 0)
 442                         return -EINVAL;
 443
 444                 /* e == 000SSSS0 */
 445                 if (e & 1)
 446                         return -EINVAL;
 447
 448                 *(z++) = (uint8_t) a << 3 | (uint8_t) b >> 2;                    /* XXXXXYYY */
 449                 *(z++) = (uint8_t) b << 6 | (uint8_t) c << 1 | (uint8_t) d >> 4; /* YYZZZZZW */
 450                 *(z++) = (uint8_t) d << 4 | (uint8_t) e >> 1;                    /* WWWWSSSS */
 451
 452                 break;
 453         case 4:
 454                 a = unbase32hexchar(x[0]);
 455                 if (a < 0)
 456                         return -EINVAL;
 457
 458                 b = unbase32hexchar(x[1]);
 459                 if (b < 0)
 460                         return -EINVAL;
 461
 462                 c = unbase32hexchar(x[2]);
 463                 if (c < 0)
 464                         return -EINVAL;
 465
 466                 d = unbase32hexchar(x[3]);
 467                 if (d < 0)
 468                         return -EINVAL;
 469
 470                 /* d == 000W0000 */
 471                 if (d & 15)
 472                         return -EINVAL;
 473
 474                 *(z++) = (uint8_t) a << 3 | (uint8_t) b >> 2;                    /* XXXXXYYY */
 475                 *(z++) = (uint8_t) b << 6 | (uint8_t) c << 1 | (uint8_t) d >> 4; /* YYZZZZZW */
 476
 477                 break;
 478         case 2:
 479                 a = unbase32hexchar(x[0]);
 480                 if (a < 0)
 481                         return -EINVAL;
 482
 483                 b = unbase32hexchar(x[1]);
 484                 if (b < 0)
 485                         return -EINVAL;
 486
 487                 /* b == 000YYY00 */
 488                 if (b & 3)
 489                         return -EINVAL;
 490
 491                 *(z++) = (uint8_t) a << 3 | (uint8_t) b >> 2; /* XXXXXYYY */
 492
 493                 break;
 494         case 0:
 495                 break;
 496         default:
 497                 return -EINVAL;
 498         }
 499
 500         *z = 0;
 501
 502         *mem = TAKE_PTR(r);
 503         *_len = len;
 504
 505         return 0;
 506 }
 507
 508 /* https://tools.ietf.org/html/rfc4648#section-4 */
 509 char base64char(int x) {
 510         static const char table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 511                                       "abcdefghijklmnopqrstuvwxyz"
 512                                       "0123456789+/";
 513         return table[x & 63];
 514 }
 515
 516 int unbase64char(char c) {
 517         unsigned offset;
 518
 519         if (c >= 'A' && c <= 'Z')
 520                 return c - 'A';
 521
 522         offset = 'Z' - 'A' + 1;
 523
 524         if (c >= 'a' && c <= 'z')
 525                 return c - 'a' + offset;
 526
 527         offset += 'z' - 'a' + 1;
 528
 529         if (c >= '0' && c <= '9')
 530                 return c - '0' + offset;
 531
 532         offset += '9' - '0' + 1;
 533
 534         if (c == '+')
 535                 return offset;
 536
 537         offset++;
 538
 539         if (c == '/')
 540                 return offset;
 541
 542         return -EINVAL;
 543 }
 544
 545 ssize_t base64mem(const void *p, size_t l, char **out) {
 546         char *r, *z;
 547         const uint8_t *x;
 548
 549         assert(p || l == 0);
 550         assert(out);
 551
 552         /* three input bytes makes four output bytes, padding is added so we must round up */
 553         z = r = malloc(4 * (l + 2) / 3 + 1);
 554         if (!r)
 555                 return -ENOMEM;
 556
 557         for (x = p; x < (const uint8_t*) p + (l / 3) * 3; x += 3) {
 558                 /* x[0] == XXXXXXXX; x[1] == YYYYYYYY; x[2] == ZZZZZZZZ */
 559                 *(z++) = base64char(x[0] >> 2);                    /* 00XXXXXX */
 560                 *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4);  /* 00XXYYYY */
 561                 *(z++) = base64char((x[1] & 15) << 2 | x[2] >> 6); /* 00YYYYZZ */
 562                 *(z++) = base64char(x[2] & 63);                    /* 00ZZZZZZ */
 563         }
 564
 565         switch (l % 3) {
 566         case 2:
 567                 *(z++) = base64char(x[0] >> 2);                   /* 00XXXXXX */
 568                 *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4); /* 00XXYYYY */
 569                 *(z++) = base64char((x[1] & 15) << 2);            /* 00YYYY00 */
 570                 *(z++) = '=';
 571
 572                 break;
 573         case 1:
 574                 *(z++) = base64char(x[0] >> 2);        /* 00XXXXXX */
 575                 *(z++) = base64char((x[0] & 3) << 4);  /* 00XX0000 */
 576                 *(z++) = '=';
 577                 *(z++) = '=';
 578
 579                 break;
 580         }
 581
 582         *z = 0;
 583         *out = r;
 584         return z - r;
 585 }
 586
 587 static int base64_append_width(
 588                 char **prefix, int plen,
 589                 const char *sep, int indent,
 590                 const void *p, size_t l,
 591                 int width) {
 592
 593         _cleanup_free_ char *x = NULL;
 594         char *t, *s;
 595         ssize_t len, slen, avail, line, lines;
 596
 597         len = base64mem(p, l, &x);
 598         if (len <= 0)
 599                 return len;
 600
 601         lines = DIV_ROUND_UP(len, width);
 602
 603         slen = strlen_ptr(sep);
 604         if (lines > (SSIZE_MAX - plen - 1 - slen) / (indent + width + 1))
 605                 return -ENOMEM;
 606
 607         t = realloc(*prefix, plen + 1 + slen + (indent + width + 1) * lines);
 608         if (!t)
 609                 return -ENOMEM;
 610
 611         memcpy_safe(t + plen, sep, slen);
 612
 613         for (line = 0, s = t + plen + slen, avail = len; line < lines; line++) {
 614                 int act = MIN(width, avail);
 615
 616                 if (line > 0 || sep) {
 617                         memset(s, ' ', indent);
 618                         s += indent;
 619                 }
 620
 621                 memcpy(s, x + width * line, act);
 622                 s += act;
 623                 *(s++) = line < lines - 1 ? '\n' : '\0';
 624                 avail -= act;
 625         }
 626         assert(avail == 0);
 627
 628         *prefix = t;
 629         return 0;
 630 }
 631
 632 int base64_append(
 633                 char **prefix, int plen,
 634                 const void *p, size_t l,
 635                 int indent, int width) {
 636
 637         if (plen > width / 2 || plen + indent > width)
 638                 /* leave indent on the left, keep last column free */
 639                 return base64_append_width(prefix, plen, "\n", indent, p, l, width - indent - 1);
 640         else
 641                 /* leave plen on the left, keep last column free */
 642                 return base64_append_width(prefix, plen, NULL, plen, p, l, width - plen - 1);
 643 }
 644
 645 static int unbase64_next(const char **p, size_t *l) {
 646         int ret;
 647
 648         assert(p);
 649         assert(l);
 650
 651         /* Find the next non-whitespace character, and decode it. If we find padding, we return it as INT_MAX. We
 652          * greedily skip all preceding and all following whitespace. */
 653
 654         for (;;) {
 655                 if (*l == 0)
 656                         return -EPIPE;
 657
 658                 if (!strchr(WHITESPACE, **p))
 659                         break;
 660
 661                 /* Skip leading whitespace */
 662                 (*p)++, (*l)--;
 663         }
 664
 665         if (**p == '=')
 666                 ret = INT_MAX; /* return padding as INT_MAX */
 667         else {
 668                 ret = unbase64char(**p);
 669                 if (ret < 0)
 670                         return ret;
 671         }
 672
 673         for (;;) {
 674                 (*p)++, (*l)--;
 675
 676                 if (*l == 0)
 677                         break;
 678                 if (!strchr(WHITESPACE, **p))
 679                         break;
 680
 681                 /* Skip following whitespace */
 682         }
 683
 684         return ret;
 685 }
 686
 687 int unbase64mem(const char *p, size_t l, void **ret, size_t *ret_size) {
 688         _cleanup_free_ uint8_t *buf = NULL;
 689         const char *x;
 690         uint8_t *z;
 691         size_t len;
 692
 693         assert(p || l == 0);
 694         assert(ret);
 695         assert(ret_size);
 696
 697         if (l == (size_t) -1)
 698                 l = strlen(p);
 699
 700         /* A group of four input bytes needs three output bytes, in case of padding we need to add two or three extra
 701          * bytes. Note that this calculation is an upper boundary, as we ignore whitespace while decoding */
 702         len = (l / 4) * 3 + (l % 4 != 0 ? (l % 4) - 1 : 0);
 703
 704         buf = malloc(len + 1);
 705         if (!buf)
 706                 return -ENOMEM;
 707
 708         for (x = p, z = buf;;) {
 709                 int a, b, c, d; /* a == 00XXXXXX; b == 00YYYYYY; c == 00ZZZZZZ; d == 00WWWWWW */
 710
 711                 a = unbase64_next(&x, &l);
 712                 if (a == -EPIPE) /* End of string */
 713                         break;
 714                 if (a < 0)
 715                         return a;
 716                 if (a == INT_MAX) /* Padding is not allowed at the beginning of a 4ch block */
 717                         return -EINVAL;
 718
 719                 b = unbase64_next(&x, &l);
 720                 if (b < 0)
 721                         return b;
 722                 if (b == INT_MAX) /* Padding is not allowed at the second character of a 4ch block either */
 723                         return -EINVAL;
 724
 725                 c = unbase64_next(&x, &l);
 726                 if (c < 0)
 727                         return c;
 728
 729                 d = unbase64_next(&x, &l);
 730                 if (d < 0)
 731                         return d;
 732
 733                 if (c == INT_MAX) { /* Padding at the third character */
 734
 735                         if (d != INT_MAX) /* If the third character is padding, the fourth must be too */
 736                                 return -EINVAL;
 737
 738                         /* b == 00YY0000 */
 739                         if (b & 15)
 740                                 return -EINVAL;
 741
 742                         if (l > 0) /* Trailing rubbish? */
 743                                 return -ENAMETOOLONG;
 744
 745                         *(z++) = (uint8_t) a << 2 | (uint8_t) (b >> 4); /* XXXXXXYY */
 746                         break;
 747                 }
 748
 749                 if (d == INT_MAX) {
 750                         /* c == 00ZZZZ00 */
 751                         if (c & 3)
 752                                 return -EINVAL;
 753
 754                         if (l > 0) /* Trailing rubbish? */
 755                                 return -ENAMETOOLONG;
 756
 757                         *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */
 758                         *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */
 759                         break;
 760                 }
 761
 762                 *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */
 763                 *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */
 764                 *(z++) = (uint8_t) c << 6 | (uint8_t) d;      /* ZZWWWWWW */
 765         }
 766
 767         *z = 0;
 768
 769         *ret_size = (size_t) (z - buf);
 770         *ret = TAKE_PTR(buf);
 771
 772         return 0;
 773 }
 774
 775 void hexdump(FILE *f, const void *p, size_t s) {
 776         const uint8_t *b = p;
 777         unsigned n = 0;
 778
 779         assert(b || s == 0);
 780
 781         if (!f)
 782                 f = stdout;
 783
 784         while (s > 0) {
 785                 size_t i;
 786
 787                 fprintf(f, "%04x  ", n);
 788
 789                 for (i = 0; i < 16; i++) {
 790
 791                         if (i >= s)
 792                                 fputs("   ", f);
 793                         else
 794                                 fprintf(f, "%02x ", b[i]);
 795
 796                         if (i == 7)
 797                                 fputc(' ', f);
 798                 }
 799
 800                 fputc(' ', f);
 801
 802                 for (i = 0; i < 16; i++) {
 803
 804                         if (i >= s)
 805                                 fputc(' ', f);
 806                         else
 807                                 fputc(isprint(b[i]) ? (char) b[i] : '.', f);
 808                 }
 809
 810                 fputc('\n', f);
 811
 812                 if (s < 16)
 813                         break;
 814
 815                 n += 16;
 816                 b += 16;
 817                 s -= 16;
 818         }
 819 }