1 /* $Id: preconv.c,v 1.6 2013/06/02 03:52:21 schwarze 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.
36 */
37
38 enum enc {
39 ENC_UTF_8, /* UTF-8 */
40 ENC_US_ASCII, /* US-ASCII */
41 ENC_LATIN_1, /* Latin-1 */
42 ENC__MAX
43 };
44
45 struct buf {
46 char *buf; /* binary input buffer */
47 size_t sz; /* size of binary buffer */
48 size_t offs; /* starting buffer offset */
49 };
50
51 struct encode {
52 const char *name;
53 int (*conv)(const struct buf *);
54 };
55
56 static int cue_enc(const struct buf *, size_t *, enum enc *);
57 static int conv_latin_1(const struct buf *);
58 static int conv_us_ascii(const struct buf *);
59 static int conv_utf_8(const struct buf *);
60 static int read_whole_file(const char *, int,
61 struct buf *, int *);
62 static void resize_buf(struct buf *, size_t);
63 static void usage(void);
64
65 static const struct encode encs[ENC__MAX] = {
66 { "utf-8", conv_utf_8 }, /* ENC_UTF_8 */
67 { "us-ascii", conv_us_ascii }, /* ENC_US_ASCII */
68 { "latin-1", conv_latin_1 }, /* ENC_LATIN_1 */
69 };
70
71 static const char *progname;
72
73 static void
74 usage(void)
75 {
76
77 fprintf(stderr, "usage: %s "
78 "[-D enc] "
79 "[-e ENC] "
80 "[file]\n", progname);
81 }
82
83 static int
84 conv_latin_1(const struct buf *b)
85 {
86 size_t i;
87 unsigned char cu;
88 const char *cp;
89
90 cp = b->buf + (int)b->offs;
91
92 /*
93 * Latin-1 falls into the first 256 code-points of Unicode, so
94 * there's no need for any sort of translation. Just make the
95 * 8-bit characters use the Unicode escape.
96 * Note that binary values 128 < v < 160 are passed through
97 * unmodified to mandoc.
98 */
99
100 for (i = b->offs; i < b->sz; i++) {
101 cu = (unsigned char)*cp++;
102 cu < 160U ? putchar(cu) : printf("\\[u%.4X]", cu);
103 }
104
105 return(1);
106 }
107
108 static int
109 conv_us_ascii(const struct buf *b)
110 {
111
112 /*
113 * US-ASCII has no conversion since it falls into the first 128
114 * bytes of Unicode.
115 */
116
117 fwrite(b->buf, 1, b->sz, stdout);
118 return(1);
119 }
120
121 static int
122 conv_utf_8(const struct buf *b)
123 {
124 int state, be;
125 unsigned int accum;
126 size_t i;
127 unsigned char cu;
128 const char *cp;
129 const long one = 1L;
130
131 cp = b->buf + (int)b->offs;
132 state = 0;
133 accum = 0U;
134 be = 0;
135
136 /* Quick test for big-endian value. */
137
138 if ( ! (*((const char *)(&one))))
139 be = 1;
140
141 for (i = b->offs; i < b->sz; i++) {
142 cu = (unsigned char)*cp++;
143 if (state) {
144 if ( ! (cu & 128) || (cu & 64)) {
145 /* Bad sequence header. */
146 return(0);
147 }
148
149 /* Accept only legitimate bit patterns. */
150
151 if (cu > 191 || cu < 128) {
152 /* Bad in-sequence bits. */
153 return(0);
154 }
155
156 accum |= (cu & 63) << --state * 6;
157
158 /*
159 * Accum is held in little-endian order as
160 * stipulated by the UTF-8 sequence coding. We
161 * need to convert to a native big-endian if our
162 * architecture requires it.
163 */
164
165 if (0 == state && be)
166 accum = (accum >> 24) |
167 ((accum << 8) & 0x00FF0000) |
168 ((accum >> 8) & 0x0000FF00) |
169 (accum << 24);
170
171 if (0 == state) {
172 accum < 128U ? putchar(accum) :
173 printf("\\[u%.4X]", accum);
174 accum = 0U;
175 }
176 } else if (cu & (1 << 7)) {
177 /*
178 * Entering a UTF-8 state: if we encounter a
179 * UTF-8 bitmask, calculate the expected UTF-8
180 * state from it.
181 */
182 for (state = 0; state < 7; state++)
183 if ( ! (cu & (1 << (7 - state))))
184 break;
185
186 /* Accept only legitimate bit patterns. */
187
188 switch (state) {
189 case (4):
190 if (cu <= 244 && cu >= 240) {
191 accum = (cu & 7) << 18;
192 break;
193 }
194 /* Bad 4-sequence start bits. */
195 return(0);
196 case (3):
197 if (cu <= 239 && cu >= 224) {
198 accum = (cu & 15) << 12;
199 break;
200 }
201 /* Bad 3-sequence start bits. */
202 return(0);
203 case (2):
204 if (cu <= 223 && cu >= 194) {
205 accum = (cu & 31) << 6;
206 break;
207 }
208 /* Bad 2-sequence start bits. */
209 return(0);
210 default:
211 /* Bad sequence bit mask. */
212 return(0);
213 }
214 state--;
215 } else
216 putchar(cu);
217 }
218
219 if (0 != state) {
220 /* Bad trailing bits. */
221 return(0);
222 }
223
224 return(1);
225 }
226
227 static void
228 resize_buf(struct buf *buf, size_t initial)
229 {
230
231 buf->sz = buf->sz > initial / 2 ?
232 2 * buf->sz : initial;
233
234 buf->buf = realloc(buf->buf, buf->sz);
235 if (NULL == buf->buf) {
236 perror(NULL);
237 exit(EXIT_FAILURE);
238 }
239 }
240
241 static int
242 read_whole_file(const char *f, int fd,
243 struct buf *fb, int *with_mmap)
244 {
245 size_t off;
246 ssize_t ssz;
247
248 #ifdef HAVE_MMAP
249 struct stat st;
250 if (-1 == fstat(fd, &st)) {
251 perror(f);
252 return(0);
253 }
254
255 /*
256 * If we're a regular file, try just reading in the whole entry
257 * via mmap(). This is faster than reading it into blocks, and
258 * since each file is only a few bytes to begin with, I'm not
259 * concerned that this is going to tank any machines.
260 */
261
262 if (S_ISREG(st.st_mode) && st.st_size >= (1U << 31)) {
263 fprintf(stderr, "%s: input too large\n", f);
264 return(0);
265 }
266
267 if (S_ISREG(st.st_mode)) {
268 *with_mmap = 1;
269 fb->sz = (size_t)st.st_size;
270 fb->buf = mmap(NULL, fb->sz, PROT_READ, MAP_SHARED, fd, 0);
271 if (fb->buf != MAP_FAILED)
272 return(1);
273 }
274 #endif
275
276 /*
277 * If this isn't a regular file (like, say, stdin), then we must
278 * go the old way and just read things in bit by bit.
279 */
280
281 *with_mmap = 0;
282 off = 0;
283 fb->sz = 0;
284 fb->buf = NULL;
285 for (;;) {
286 if (off == fb->sz && fb->sz == (1U << 31)) {
287 fprintf(stderr, "%s: input too large\n", f);
288 break;
289 }
290
291 if (off == fb->sz)
292 resize_buf(fb, 65536);
293
294 ssz = read(fd, fb->buf + (int)off, fb->sz - off);
295 if (ssz == 0) {
296 fb->sz = off;
297 return(1);
298 }
299 if (ssz == -1) {
300 perror(f);
301 break;
302 }
303 off += (size_t)ssz;
304 }
305
306 free(fb->buf);
307 fb->buf = NULL;
308 return(0);
309 }
310
311 static int
312 cue_enc(const struct buf *b, size_t *offs, enum enc *enc)
313 {
314 const char *ln, *eoln, *eoph;
315 size_t sz, phsz, nsz;
316 int i;
317
318 ln = b->buf + (int)*offs;
319 sz = b->sz - *offs;
320
321 /* Look for the end-of-line. */
322
323 if (NULL == (eoln = memchr(ln, '\n', sz)))
324 return(-1);
325
326 /* Set next-line marker. */
327
328 *offs = (size_t)((eoln + 1) - b->buf);
329
330 /* Check if we have the correct header/trailer. */
331
332 if ((sz = (size_t)(eoln - ln)) < 10 ||
333 memcmp(ln, ".\\\" -*-", 7) ||
334 memcmp(eoln - 3, "-*-", 3))
335 return(0);
336
337 /* Move after the header and adjust for the trailer. */
338
339 ln += 7;
340 sz -= 10;
341
342 while (sz > 0) {
343 while (sz > 0 && ' ' == *ln) {
344 ln++;
345 sz--;
346 }
347 if (0 == sz)
348 break;
349
350 /* Find the end-of-phrase marker (or eoln). */
351
352 if (NULL == (eoph = memchr(ln, ';', sz)))
353 eoph = eoln - 3;
354 else
355 eoph++;
356
357 /* Only account for the "coding" phrase. */
358
359 if ((phsz = (size_t)(eoph - ln)) < 7 ||
360 strncasecmp(ln, "coding:", 7)) {
361 sz -= phsz;
362 ln += phsz;
363 continue;
364 }
365
366 sz -= 7;
367 ln += 7;
368
369 while (sz > 0 && ' ' == *ln) {
370 ln++;
371 sz--;
372 }
373 if (0 == sz)
374 break;
375
376 /* Check us against known encodings. */
377
378 for (i = 0; i < (int)ENC__MAX; i++) {
379 nsz = strlen(encs[i].name);
380 if (phsz < nsz)
381 continue;
382 if (strncasecmp(ln, encs[i].name, nsz))
383 continue;
384
385 *enc = (enum enc)i;
386 return(1);
387 }
388
389 /* Unknown encoding. */
390
391 *enc = ENC__MAX;
392 return(1);
393 }
394
395 return(0);
396 }
397
398 int
399 main(int argc, char *argv[])
400 {
401 int i, ch, map, fd, rc;
402 struct buf b;
403 const char *fn;
404 enum enc enc, def;
405 unsigned char bom[3] = { 0xEF, 0xBB, 0xBF };
406 size_t offs;
407 extern int optind;
408 extern char *optarg;
409
410 progname = strrchr(argv[0], '/');
411 if (progname == NULL)
412 progname = argv[0];
413 else
414 ++progname;
415
416 fn = "<stdin>";
417 fd = STDIN_FILENO;
418 rc = EXIT_FAILURE;
419 enc = def = ENC__MAX;
420 map = 0;
421
422 memset(&b, 0, sizeof(struct buf));
423
424 while (-1 != (ch = getopt(argc, argv, "D:e:rdvh")))
425 switch (ch) {
426 case ('D'):
427 /* FALLTHROUGH */
428 case ('e'):
429 for (i = 0; i < (int)ENC__MAX; i++) {
430 if (strcasecmp(optarg, encs[i].name))
431 continue;
432 break;
433 }
434 if (i < (int)ENC__MAX) {
435 if ('D' == ch)
436 def = (enum enc)i;
437 else
438 enc = (enum enc)i;
439 break;
440 }
441
442 fprintf(stderr, "%s: Bad encoding\n", optarg);
443 return(EXIT_FAILURE);
444 case ('r'):
445 /* FALLTHROUGH */
446 case ('d'):
447 /* FALLTHROUGH */
448 case ('v'):
449 /* Compatibility with GNU preconv. */
450 break;
451 case ('h'):
452 /* Compatibility with GNU preconv. */
453 /* FALLTHROUGH */
454 default:
455 usage();
456 return(EXIT_FAILURE);
457 }
458
459 argc -= optind;
460 argv += optind;
461
462 /*
463 * Open and read the first argument on the command-line.
464 * If we don't have one, we default to stdin.
465 */
466
467 if (argc > 0) {
468 fn = *argv;
469 fd = open(fn, O_RDONLY, 0);
470 if (-1 == fd) {
471 perror(fn);
472 return(EXIT_FAILURE);
473 }
474 }
475
476 if ( ! read_whole_file(fn, fd, &b, &map))
477 goto out;
478
479 /* Try to read the UTF-8 BOM. */
480
481 if (ENC__MAX == enc)
482 if (b.sz > 3 && 0 == memcmp(b.buf, bom, 3)) {
483 b.offs = 3;
484 enc = ENC_UTF_8;
485 }
486
487 /* Try reading from the "-*-" cue. */
488
489 if (ENC__MAX == enc) {
490 offs = b.offs;
491 ch = cue_enc(&b, &offs, &enc);
492 if (0 == ch)
493 ch = cue_enc(&b, &offs, &enc);
494 }
495
496 /*
497 * No encoding has been detected.
498 * Thus, we either fall into our default encoder, if specified,
499 * or use Latin-1 if all else fails.
500 */
501
502 if (ENC__MAX == enc)
503 enc = ENC__MAX == def ? ENC_LATIN_1 : def;
504
505 if ( ! (*encs[(int)enc].conv)(&b)) {
506 fprintf(stderr, "%s: Bad encoding\n", fn);
507 goto out;
508 }
509
510 rc = EXIT_SUCCESS;
511 out:
512 #ifdef HAVE_MMAP
513 if (map)
514 munmap(b.buf, b.sz);
515 else
516 #endif
517 free(b.buf);
518
519 if (fd > STDIN_FILENO)
520 close(fd);
521
522 return(rc);
523 }