| 1 | /* $Id: preconv.c,v 1.5 2011/07/24 18:15:14 kristaps Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv> |
| 4 | * |
| 5 | * Permission to use, copy, modify, and distribute this software for any |
| 6 | * purpose with or without fee is hereby granted, provided that the above |
| 7 | * copyright notice and this permission notice appear in all copies. |
| 8 | * |
| 9 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| 15 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 16 | */ |
| 17 | #ifdef HAVE_CONFIG_H |
| 18 | #include "config.h" |
| 19 | #endif |
| 20 | |
| 21 | #ifdef HAVE_MMAP |
| 22 | #include <sys/stat.h> |
| 23 | #include <sys/mman.h> |
| 24 | #endif |
| 25 | |
| 26 | #include <assert.h> |
| 27 | #include <fcntl.h> |
| 28 | #include <stdio.h> |
| 29 | #include <stdlib.h> |
| 30 | #include <string.h> |
| 31 | #include <unistd.h> |
| 32 | |
| 33 | /* |
| 34 | * The read_whole_file() and resize_buf() functions are copied from |
| 35 | * read.c, including all dependency code (MAP_FILE, etc.). |
| 36 | */ |
| 37 | |
| 38 | #ifndef MAP_FILE |
| 39 | #define MAP_FILE 0 |
| 40 | #endif |
| 41 | |
| 42 | enum enc { |
| 43 | ENC_UTF_8, /* UTF-8 */ |
| 44 | ENC_US_ASCII, /* US-ASCII */ |
| 45 | ENC_LATIN_1, /* Latin-1 */ |
| 46 | ENC__MAX |
| 47 | }; |
| 48 | |
| 49 | struct buf { |
| 50 | char *buf; /* binary input buffer */ |
| 51 | size_t sz; /* size of binary buffer */ |
| 52 | size_t offs; /* starting buffer offset */ |
| 53 | }; |
| 54 | |
| 55 | struct encode { |
| 56 | const char *name; |
| 57 | int (*conv)(const struct buf *); |
| 58 | }; |
| 59 | |
| 60 | static int cue_enc(const struct buf *, size_t *, enum enc *); |
| 61 | static int conv_latin_1(const struct buf *); |
| 62 | static int conv_us_ascii(const struct buf *); |
| 63 | static int conv_utf_8(const struct buf *); |
| 64 | static int read_whole_file(const char *, int, |
| 65 | struct buf *, int *); |
| 66 | static void resize_buf(struct buf *, size_t); |
| 67 | static void usage(void); |
| 68 | |
| 69 | static const struct encode encs[ENC__MAX] = { |
| 70 | { "utf-8", conv_utf_8 }, /* ENC_UTF_8 */ |
| 71 | { "us-ascii", conv_us_ascii }, /* ENC_US_ASCII */ |
| 72 | { "latin-1", conv_latin_1 }, /* ENC_LATIN_1 */ |
| 73 | }; |
| 74 | |
| 75 | static const char *progname; |
| 76 | |
| 77 | static void |
| 78 | usage(void) |
| 79 | { |
| 80 | |
| 81 | fprintf(stderr, "usage: %s " |
| 82 | "[-D enc] " |
| 83 | "[-e ENC] " |
| 84 | "[file]\n", progname); |
| 85 | } |
| 86 | |
| 87 | static int |
| 88 | conv_latin_1(const struct buf *b) |
| 89 | { |
| 90 | size_t i; |
| 91 | unsigned char cu; |
| 92 | const char *cp; |
| 93 | |
| 94 | cp = b->buf + (int)b->offs; |
| 95 | |
| 96 | /* |
| 97 | * Latin-1 falls into the first 256 code-points of Unicode, so |
| 98 | * there's no need for any sort of translation. Just make the |
| 99 | * 8-bit characters use the Unicode escape. |
| 100 | * Note that binary values 128 < v < 160 are passed through |
| 101 | * unmodified to mandoc. |
| 102 | */ |
| 103 | |
| 104 | for (i = b->offs; i < b->sz; i++) { |
| 105 | cu = (unsigned char)*cp++; |
| 106 | cu < 160U ? putchar(cu) : printf("\\[u%.4X]", cu); |
| 107 | } |
| 108 | |
| 109 | return(1); |
| 110 | } |
| 111 | |
| 112 | static int |
| 113 | conv_us_ascii(const struct buf *b) |
| 114 | { |
| 115 | |
| 116 | /* |
| 117 | * US-ASCII has no conversion since it falls into the first 128 |
| 118 | * bytes of Unicode. |
| 119 | */ |
| 120 | |
| 121 | fwrite(b->buf, 1, b->sz, stdout); |
| 122 | return(1); |
| 123 | } |
| 124 | |
| 125 | static int |
| 126 | conv_utf_8(const struct buf *b) |
| 127 | { |
| 128 | int state, be; |
| 129 | unsigned int accum; |
| 130 | size_t i; |
| 131 | unsigned char cu; |
| 132 | const char *cp; |
| 133 | const long one = 1L; |
| 134 | |
| 135 | cp = b->buf + (int)b->offs; |
| 136 | state = 0; |
| 137 | accum = 0U; |
| 138 | be = 0; |
| 139 | |
| 140 | /* Quick test for big-endian value. */ |
| 141 | |
| 142 | if ( ! (*((const char *)(&one)))) |
| 143 | be = 1; |
| 144 | |
| 145 | for (i = b->offs; i < b->sz; i++) { |
| 146 | cu = (unsigned char)*cp++; |
| 147 | if (state) { |
| 148 | if ( ! (cu & 128) || (cu & 64)) { |
| 149 | /* Bad sequence header. */ |
| 150 | return(0); |
| 151 | } |
| 152 | |
| 153 | /* Accept only legitimate bit patterns. */ |
| 154 | |
| 155 | if (cu > 191 || cu < 128) { |
| 156 | /* Bad in-sequence bits. */ |
| 157 | return(0); |
| 158 | } |
| 159 | |
| 160 | accum |= (cu & 63) << --state * 6; |
| 161 | |
| 162 | /* |
| 163 | * Accum is held in little-endian order as |
| 164 | * stipulated by the UTF-8 sequence coding. We |
| 165 | * need to convert to a native big-endian if our |
| 166 | * architecture requires it. |
| 167 | */ |
| 168 | |
| 169 | if (0 == state && be) |
| 170 | accum = (accum >> 24) | |
| 171 | ((accum << 8) & 0x00FF0000) | |
| 172 | ((accum >> 8) & 0x0000FF00) | |
| 173 | (accum << 24); |
| 174 | |
| 175 | if (0 == state) { |
| 176 | accum < 128U ? putchar(accum) : |
| 177 | printf("\\[u%.4X]", accum); |
| 178 | accum = 0U; |
| 179 | } |
| 180 | } else if (cu & (1 << 7)) { |
| 181 | /* |
| 182 | * Entering a UTF-8 state: if we encounter a |
| 183 | * UTF-8 bitmask, calculate the expected UTF-8 |
| 184 | * state from it. |
| 185 | */ |
| 186 | for (state = 0; state < 7; state++) |
| 187 | if ( ! (cu & (1 << (7 - state)))) |
| 188 | break; |
| 189 | |
| 190 | /* Accept only legitimate bit patterns. */ |
| 191 | |
| 192 | switch (state) { |
| 193 | case (4): |
| 194 | if (cu <= 244 && cu >= 240) { |
| 195 | accum = (cu & 7) << 18; |
| 196 | break; |
| 197 | } |
| 198 | /* Bad 4-sequence start bits. */ |
| 199 | return(0); |
| 200 | case (3): |
| 201 | if (cu <= 239 && cu >= 224) { |
| 202 | accum = (cu & 15) << 12; |
| 203 | break; |
| 204 | } |
| 205 | /* Bad 3-sequence start bits. */ |
| 206 | return(0); |
| 207 | case (2): |
| 208 | if (cu <= 223 && cu >= 194) { |
| 209 | accum = (cu & 31) << 6; |
| 210 | break; |
| 211 | } |
| 212 | /* Bad 2-sequence start bits. */ |
| 213 | return(0); |
| 214 | default: |
| 215 | /* Bad sequence bit mask. */ |
| 216 | return(0); |
| 217 | } |
| 218 | state--; |
| 219 | } else |
| 220 | putchar(cu); |
| 221 | } |
| 222 | |
| 223 | if (0 != state) { |
| 224 | /* Bad trailing bits. */ |
| 225 | return(0); |
| 226 | } |
| 227 | |
| 228 | return(1); |
| 229 | } |
| 230 | |
| 231 | static void |
| 232 | resize_buf(struct buf *buf, size_t initial) |
| 233 | { |
| 234 | |
| 235 | buf->sz = buf->sz > initial / 2 ? |
| 236 | 2 * buf->sz : initial; |
| 237 | |
| 238 | buf->buf = realloc(buf->buf, buf->sz); |
| 239 | if (NULL == buf->buf) { |
| 240 | perror(NULL); |
| 241 | exit(EXIT_FAILURE); |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | static int |
| 246 | read_whole_file(const char *f, int fd, |
| 247 | struct buf *fb, int *with_mmap) |
| 248 | { |
| 249 | size_t off; |
| 250 | ssize_t ssz; |
| 251 | |
| 252 | #ifdef HAVE_MMAP |
| 253 | struct stat st; |
| 254 | if (-1 == fstat(fd, &st)) { |
| 255 | perror(f); |
| 256 | return(0); |
| 257 | } |
| 258 | |
| 259 | /* |
| 260 | * If we're a regular file, try just reading in the whole entry |
| 261 | * via mmap(). This is faster than reading it into blocks, and |
| 262 | * since each file is only a few bytes to begin with, I'm not |
| 263 | * concerned that this is going to tank any machines. |
| 264 | */ |
| 265 | |
| 266 | if (S_ISREG(st.st_mode) && st.st_size >= (1U << 31)) { |
| 267 | fprintf(stderr, "%s: input too large\n", f); |
| 268 | return(0); |
| 269 | } |
| 270 | |
| 271 | if (S_ISREG(st.st_mode)) { |
| 272 | *with_mmap = 1; |
| 273 | fb->sz = (size_t)st.st_size; |
| 274 | fb->buf = mmap(NULL, fb->sz, PROT_READ, |
| 275 | MAP_FILE|MAP_SHARED, fd, 0); |
| 276 | if (fb->buf != MAP_FAILED) |
| 277 | return(1); |
| 278 | } |
| 279 | #endif |
| 280 | |
| 281 | /* |
| 282 | * If this isn't a regular file (like, say, stdin), then we must |
| 283 | * go the old way and just read things in bit by bit. |
| 284 | */ |
| 285 | |
| 286 | *with_mmap = 0; |
| 287 | off = 0; |
| 288 | fb->sz = 0; |
| 289 | fb->buf = NULL; |
| 290 | for (;;) { |
| 291 | if (off == fb->sz && fb->sz == (1U << 31)) { |
| 292 | fprintf(stderr, "%s: input too large\n", f); |
| 293 | break; |
| 294 | } |
| 295 | |
| 296 | if (off == fb->sz) |
| 297 | resize_buf(fb, 65536); |
| 298 | |
| 299 | ssz = read(fd, fb->buf + (int)off, fb->sz - off); |
| 300 | if (ssz == 0) { |
| 301 | fb->sz = off; |
| 302 | return(1); |
| 303 | } |
| 304 | if (ssz == -1) { |
| 305 | perror(f); |
| 306 | break; |
| 307 | } |
| 308 | off += (size_t)ssz; |
| 309 | } |
| 310 | |
| 311 | free(fb->buf); |
| 312 | fb->buf = NULL; |
| 313 | return(0); |
| 314 | } |
| 315 | |
| 316 | static int |
| 317 | cue_enc(const struct buf *b, size_t *offs, enum enc *enc) |
| 318 | { |
| 319 | const char *ln, *eoln, *eoph; |
| 320 | size_t sz, phsz, nsz; |
| 321 | int i; |
| 322 | |
| 323 | ln = b->buf + (int)*offs; |
| 324 | sz = b->sz - *offs; |
| 325 | |
| 326 | /* Look for the end-of-line. */ |
| 327 | |
| 328 | if (NULL == (eoln = memchr(ln, '\n', sz))) |
| 329 | return(-1); |
| 330 | |
| 331 | /* Set next-line marker. */ |
| 332 | |
| 333 | *offs = (size_t)((eoln + 1) - b->buf); |
| 334 | |
| 335 | /* Check if we have the correct header/trailer. */ |
| 336 | |
| 337 | if ((sz = (size_t)(eoln - ln)) < 10 || |
| 338 | memcmp(ln, ".\\\" -*-", 7) || |
| 339 | memcmp(eoln - 3, "-*-", 3)) |
| 340 | return(0); |
| 341 | |
| 342 | /* Move after the header and adjust for the trailer. */ |
| 343 | |
| 344 | ln += 7; |
| 345 | sz -= 10; |
| 346 | |
| 347 | while (sz > 0) { |
| 348 | while (sz > 0 && ' ' == *ln) { |
| 349 | ln++; |
| 350 | sz--; |
| 351 | } |
| 352 | if (0 == sz) |
| 353 | break; |
| 354 | |
| 355 | /* Find the end-of-phrase marker (or eoln). */ |
| 356 | |
| 357 | if (NULL == (eoph = memchr(ln, ';', sz))) |
| 358 | eoph = eoln - 3; |
| 359 | else |
| 360 | eoph++; |
| 361 | |
| 362 | /* Only account for the "coding" phrase. */ |
| 363 | |
| 364 | if ((phsz = (size_t)(eoph - ln)) < 7 || |
| 365 | strncasecmp(ln, "coding:", 7)) { |
| 366 | sz -= phsz; |
| 367 | ln += phsz; |
| 368 | continue; |
| 369 | } |
| 370 | |
| 371 | sz -= 7; |
| 372 | ln += 7; |
| 373 | |
| 374 | while (sz > 0 && ' ' == *ln) { |
| 375 | ln++; |
| 376 | sz--; |
| 377 | } |
| 378 | if (0 == sz) |
| 379 | break; |
| 380 | |
| 381 | /* Check us against known encodings. */ |
| 382 | |
| 383 | for (i = 0; i < (int)ENC__MAX; i++) { |
| 384 | nsz = strlen(encs[i].name); |
| 385 | if (phsz < nsz) |
| 386 | continue; |
| 387 | if (strncasecmp(ln, encs[i].name, nsz)) |
| 388 | continue; |
| 389 | |
| 390 | *enc = (enum enc)i; |
| 391 | return(1); |
| 392 | } |
| 393 | |
| 394 | /* Unknown encoding. */ |
| 395 | |
| 396 | *enc = ENC__MAX; |
| 397 | return(1); |
| 398 | } |
| 399 | |
| 400 | return(0); |
| 401 | } |
| 402 | |
| 403 | int |
| 404 | main(int argc, char *argv[]) |
| 405 | { |
| 406 | int i, ch, map, fd, rc; |
| 407 | struct buf b; |
| 408 | const char *fn; |
| 409 | enum enc enc, def; |
| 410 | unsigned char bom[3] = { 0xEF, 0xBB, 0xBF }; |
| 411 | size_t offs; |
| 412 | extern int optind; |
| 413 | extern char *optarg; |
| 414 | |
| 415 | progname = strrchr(argv[0], '/'); |
| 416 | if (progname == NULL) |
| 417 | progname = argv[0]; |
| 418 | else |
| 419 | ++progname; |
| 420 | |
| 421 | fn = "<stdin>"; |
| 422 | fd = STDIN_FILENO; |
| 423 | rc = EXIT_FAILURE; |
| 424 | enc = def = ENC__MAX; |
| 425 | map = 0; |
| 426 | |
| 427 | memset(&b, 0, sizeof(struct buf)); |
| 428 | |
| 429 | while (-1 != (ch = getopt(argc, argv, "D:e:rdvh"))) |
| 430 | switch (ch) { |
| 431 | case ('D'): |
| 432 | /* FALLTHROUGH */ |
| 433 | case ('e'): |
| 434 | for (i = 0; i < (int)ENC__MAX; i++) { |
| 435 | if (strcasecmp(optarg, encs[i].name)) |
| 436 | continue; |
| 437 | break; |
| 438 | } |
| 439 | if (i < (int)ENC__MAX) { |
| 440 | if ('D' == ch) |
| 441 | def = (enum enc)i; |
| 442 | else |
| 443 | enc = (enum enc)i; |
| 444 | break; |
| 445 | } |
| 446 | |
| 447 | fprintf(stderr, "%s: Bad encoding\n", optarg); |
| 448 | return(EXIT_FAILURE); |
| 449 | case ('r'): |
| 450 | /* FALLTHROUGH */ |
| 451 | case ('d'): |
| 452 | /* FALLTHROUGH */ |
| 453 | case ('v'): |
| 454 | /* Compatibility with GNU preconv. */ |
| 455 | break; |
| 456 | case ('h'): |
| 457 | /* Compatibility with GNU preconv. */ |
| 458 | /* FALLTHROUGH */ |
| 459 | default: |
| 460 | usage(); |
| 461 | return(EXIT_FAILURE); |
| 462 | } |
| 463 | |
| 464 | argc -= optind; |
| 465 | argv += optind; |
| 466 | |
| 467 | /* |
| 468 | * Open and read the first argument on the command-line. |
| 469 | * If we don't have one, we default to stdin. |
| 470 | */ |
| 471 | |
| 472 | if (argc > 0) { |
| 473 | fn = *argv; |
| 474 | fd = open(fn, O_RDONLY, 0); |
| 475 | if (-1 == fd) { |
| 476 | perror(fn); |
| 477 | return(EXIT_FAILURE); |
| 478 | } |
| 479 | } |
| 480 | |
| 481 | if ( ! read_whole_file(fn, fd, &b, &map)) |
| 482 | goto out; |
| 483 | |
| 484 | /* Try to read the UTF-8 BOM. */ |
| 485 | |
| 486 | if (ENC__MAX == enc) |
| 487 | if (b.sz > 3 && 0 == memcmp(b.buf, bom, 3)) { |
| 488 | b.offs = 3; |
| 489 | enc = ENC_UTF_8; |
| 490 | } |
| 491 | |
| 492 | /* Try reading from the "-*-" cue. */ |
| 493 | |
| 494 | if (ENC__MAX == enc) { |
| 495 | offs = b.offs; |
| 496 | ch = cue_enc(&b, &offs, &enc); |
| 497 | if (0 == ch) |
| 498 | ch = cue_enc(&b, &offs, &enc); |
| 499 | } |
| 500 | |
| 501 | /* |
| 502 | * No encoding has been detected. |
| 503 | * Thus, we either fall into our default encoder, if specified, |
| 504 | * or use Latin-1 if all else fails. |
| 505 | */ |
| 506 | |
| 507 | if (ENC__MAX == enc) |
| 508 | enc = ENC__MAX == def ? ENC_LATIN_1 : def; |
| 509 | |
| 510 | if ( ! (*encs[(int)enc].conv)(&b)) { |
| 511 | fprintf(stderr, "%s: Bad encoding\n", fn); |
| 512 | goto out; |
| 513 | } |
| 514 | |
| 515 | rc = EXIT_SUCCESS; |
| 516 | out: |
| 517 | #ifdef HAVE_MMAP |
| 518 | if (map) |
| 519 | munmap(b.buf, b.sz); |
| 520 | else |
| 521 | #endif |
| 522 | free(b.buf); |
| 523 | |
| 524 | if (fd > STDIN_FILENO) |
| 525 | close(fd); |
| 526 | |
| 527 | return(rc); |
| 528 | } |