xref: /freebsd/contrib/libc-vis/vis.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*	$NetBSD: vis.c,v 1.83 2023/08/12 12:48:52 riastradh Exp $	*/
2 
3 /*-
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*-
33  * Copyright (c) 1999, 2005 The NetBSD Foundation, Inc.
34  * All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  *
45  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
46  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
47  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
48  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
49  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
50  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
51  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
52  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
53  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
54  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
55  * POSSIBILITY OF SUCH DAMAGE.
56  */
57 
58 #include <sys/cdefs.h>
59 #if defined(LIBC_SCCS) && !defined(lint)
60 __RCSID("$NetBSD: vis.c,v 1.83 2023/08/12 12:48:52 riastradh Exp $");
61 #endif /* LIBC_SCCS and not lint */
62 #ifdef __FBSDID
63 __FBSDID("$FreeBSD$");
64 #define	_DIAGASSERT(x)	assert(x)
65 #endif
66 
67 #include "namespace.h"
68 #include <sys/types.h>
69 #include <sys/param.h>
70 
71 #include <assert.h>
72 #include <vis.h>
73 #include <errno.h>
74 #include <stdint.h>
75 #include <stdlib.h>
76 #include <wchar.h>
77 #include <wctype.h>
78 
79 #ifdef __weak_alias
80 __weak_alias(strvisx,_strvisx)
81 #endif
82 
83 #if !HAVE_VIS || !HAVE_SVIS
84 #include <ctype.h>
85 #include <limits.h>
86 #include <stdio.h>
87 #include <string.h>
88 
89 /*
90  * The reason for going through the trouble to deal with character encodings
91  * in vis(3), is that we use this to safe encode output of commands. This
92  * safe encoding varies depending on the character set. For example if we
93  * display ps output in French, we don't want to display French characters
94  * as M-foo.
95  */
96 
97 static wchar_t *do_svis(wchar_t *, wint_t, int, wint_t, const wchar_t *);
98 
99 #undef BELL
100 #define BELL L'\a'
101 
102 #if defined(LC_C_LOCALE)
103 #define iscgraph(c)      isgraph_l(c, LC_C_LOCALE)
104 #else
105 /* Keep it simple for now, no locale stuff */
106 #define iscgraph(c)	isgraph(c)
107 #ifdef notyet
108 #include <locale.h>
109 static int
110 iscgraph(int c) {
111 	int rv;
112 	char *ol;
113 
114 	ol = setlocale(LC_CTYPE, "C");
115 	rv = isgraph(c);
116 	if (ol)
117 		setlocale(LC_CTYPE, ol);
118 	return rv;
119 }
120 #endif
121 #endif
122 
123 #define ISGRAPH(flags, c) \
124     (((flags) & VIS_NOLOCALE) ? iscgraph(c) : iswgraph(c))
125 
126 #define iswoctal(c)	(((u_char)(c)) >= L'0' && ((u_char)(c)) <= L'7')
127 #define iswwhite(c)	(c == L' ' || c == L'\t' || c == L'\n')
128 #define iswsafe(c)	(c == L'\b' || c == BELL || c == L'\r')
129 #define xtoa(c)		L"0123456789abcdef"[c]
130 #define XTOA(c)		L"0123456789ABCDEF"[c]
131 
132 #define MAXEXTRAS	30
133 
134 static const wchar_t char_shell[] = L"'`\";&<>()|{}]\\$!^~";
135 static const wchar_t char_glob[] = L"*?[#";
136 
137 #if !HAVE_NBTOOL_CONFIG_H
138 #ifndef __NetBSD__
139 /*
140  * On NetBSD MB_LEN_MAX is currently 32 which does not fit on any integer
141  * integral type and it is probably wrong, since currently the maximum
142  * number of bytes and character needs is 6. Until this is fixed, the
143  * loops below are using sizeof(uint64_t) - 1 instead of MB_LEN_MAX, and
144  * the assertion is commented out.
145  */
146 #ifdef __FreeBSD__
147 /*
148  * On FreeBSD including <sys/systm.h> for CTASSERT only works in kernel
149  * mode.
150  */
151 #ifndef CTASSERT
152 #define CTASSERT(x)             _CTASSERT(x, __LINE__)
153 #define _CTASSERT(x, y)         __CTASSERT(x, y)
154 #define __CTASSERT(x, y)        typedef char __assert ## y[(x) ? 1 : -1]
155 #endif
156 #endif /* __FreeBSD__ */
157 CTASSERT(MB_LEN_MAX <= sizeof(uint64_t));
158 #endif /* !__NetBSD__ */
159 #endif
160 
161 /*
162  * This is do_hvis, for HTTP style (RFC 1808)
163  */
164 static wchar_t *
165 do_hvis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
166 {
167 	if (iswalnum(c)
168 	    /* safe */
169 	    || c == L'$' || c == L'-' || c == L'_' || c == L'.' || c == L'+'
170 	    /* extra */
171 	    || c == L'!' || c == L'*' || c == L'\'' || c == L'(' || c == L')'
172 	    || c == L',')
173 		dst = do_svis(dst, c, flags, nextc, extra);
174 	else {
175 		*dst++ = L'%';
176 		*dst++ = xtoa(((unsigned int)c >> 4) & 0xf);
177 		*dst++ = xtoa((unsigned int)c & 0xf);
178 	}
179 
180 	return dst;
181 }
182 
183 /*
184  * This is do_mvis, for Quoted-Printable MIME (RFC 2045)
185  * NB: No handling of long lines or CRLF.
186  */
187 static wchar_t *
188 do_mvis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
189 {
190 	if ((c != L'\n') &&
191 	    /* Space at the end of the line */
192 	    ((iswspace(c) && (nextc == L'\r' || nextc == L'\n')) ||
193 	    /* Out of range */
194 	    (!iswspace(c) && (c < 33 || (c > 60 && c < 62) || c > 126)) ||
195 	    /* Specific char to be escaped */
196 	    wcschr(L"#$@[\\]^`{|}~", c) != NULL)) {
197 		*dst++ = L'=';
198 		*dst++ = XTOA(((unsigned int)c >> 4) & 0xf);
199 		*dst++ = XTOA((unsigned int)c & 0xf);
200 	} else
201 		dst = do_svis(dst, c, flags, nextc, extra);
202 	return dst;
203 }
204 
205 /*
206  * Output single byte of multibyte character.
207  */
208 static wchar_t *
209 do_mbyte(wchar_t *dst, wint_t c, int flags, wint_t nextc, int iswextra)
210 {
211 	if (flags & VIS_CSTYLE) {
212 		switch (c) {
213 		case L'\n':
214 			*dst++ = L'\\'; *dst++ = L'n';
215 			return dst;
216 		case L'\r':
217 			*dst++ = L'\\'; *dst++ = L'r';
218 			return dst;
219 		case L'\b':
220 			*dst++ = L'\\'; *dst++ = L'b';
221 			return dst;
222 		case BELL:
223 			*dst++ = L'\\'; *dst++ = L'a';
224 			return dst;
225 		case L'\v':
226 			*dst++ = L'\\'; *dst++ = L'v';
227 			return dst;
228 		case L'\t':
229 			*dst++ = L'\\'; *dst++ = L't';
230 			return dst;
231 		case L'\f':
232 			*dst++ = L'\\'; *dst++ = L'f';
233 			return dst;
234 		case L' ':
235 			*dst++ = L'\\'; *dst++ = L's';
236 			return dst;
237 		case L'\0':
238 			*dst++ = L'\\'; *dst++ = L'0';
239 			if (iswoctal(nextc)) {
240 				*dst++ = L'0';
241 				*dst++ = L'0';
242 			}
243 			return dst;
244 		/* We cannot encode these characters in VIS_CSTYLE
245 		 * because they special meaning */
246 		case L'n':
247 		case L'r':
248 		case L'b':
249 		case L'a':
250 		case L'v':
251 		case L't':
252 		case L'f':
253 		case L's':
254 		case L'0':
255 		case L'M':
256 		case L'^':
257 		case L'$': /* vis(1) -l */
258 			break;
259 		default:
260 			if (ISGRAPH(flags, c) && !iswoctal(c)) {
261 				*dst++ = L'\\';
262 				*dst++ = c;
263 				return dst;
264 			}
265 		}
266 	}
267 	if (iswextra || ((c & 0177) == L' ') || (flags & VIS_OCTAL)) {
268 		*dst++ = L'\\';
269 		*dst++ = (u_char)(((u_int32_t)(u_char)c >> 6) & 03) + L'0';
270 		*dst++ = (u_char)(((u_int32_t)(u_char)c >> 3) & 07) + L'0';
271 		*dst++ =			     (c	      & 07) + L'0';
272 	} else {
273 		if ((flags & VIS_NOSLASH) == 0)
274 			*dst++ = L'\\';
275 
276 		if (c & 0200) {
277 			c &= 0177;
278 			*dst++ = L'M';
279 		}
280 
281 		if (iswcntrl(c)) {
282 			*dst++ = L'^';
283 			if (c == 0177)
284 				*dst++ = L'?';
285 			else
286 				*dst++ = c + L'@';
287 		} else {
288 			*dst++ = L'-';
289 			*dst++ = c;
290 		}
291 	}
292 
293 	return dst;
294 }
295 
296 /*
297  * This is do_vis, the central code of vis.
298  * dst:	      Pointer to the destination buffer
299  * c:	      Character to encode
300  * flags:     Flags word
301  * nextc:     The character following 'c'
302  * extra:     Pointer to the list of extra characters to be
303  *	      backslash-protected.
304  */
305 static wchar_t *
306 do_svis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
307 {
308 	int iswextra, i, shft;
309 	uint64_t bmsk, wmsk;
310 
311 	iswextra = wcschr(extra, c) != NULL;
312 	if (!iswextra && (ISGRAPH(flags, c) || iswwhite(c) ||
313 	    ((flags & VIS_SAFE) && iswsafe(c)))) {
314 		*dst++ = c;
315 		return dst;
316 	}
317 
318 	/* See comment in istrsenvisx() output loop, below. */
319 	wmsk = 0;
320 	for (i = sizeof(wmsk) - 1; i >= 0; i--) {
321 		shft = i * NBBY;
322 		bmsk = (uint64_t)0xffLL << shft;
323 		wmsk |= bmsk;
324 		if ((c & wmsk) || i == 0)
325 			dst = do_mbyte(dst, (wint_t)(
326 			    (uint64_t)(c & bmsk) >> shft),
327 			    flags, nextc, iswextra);
328 	}
329 
330 	return dst;
331 }
332 
333 typedef wchar_t *(*visfun_t)(wchar_t *, wint_t, int, wint_t, const wchar_t *);
334 
335 /*
336  * Return the appropriate encoding function depending on the flags given.
337  */
338 static visfun_t
339 getvisfun(int flags)
340 {
341 	if (flags & VIS_HTTPSTYLE)
342 		return do_hvis;
343 	if (flags & VIS_MIMESTYLE)
344 		return do_mvis;
345 	return do_svis;
346 }
347 
348 /*
349  * Expand list of extra characters to not visually encode.
350  */
351 static wchar_t *
352 makeextralist(int flags, const char *src)
353 {
354 	wchar_t *dst, *d;
355 	size_t len;
356 	const wchar_t *s;
357 	mbstate_t mbstate;
358 
359 	bzero(&mbstate, sizeof(mbstate));
360 	len = strlen(src);
361 	if ((dst = calloc(len + MAXEXTRAS, sizeof(*dst))) == NULL)
362 		return NULL;
363 
364 	memset(&mbstate, 0, sizeof(mbstate));
365 	if ((flags & VIS_NOLOCALE)
366 	    || mbsrtowcs(dst, &src, len, &mbstate) == (size_t)-1) {
367 		size_t i;
368 		for (i = 0; i < len; i++)
369 			dst[i] = (wchar_t)(u_char)src[i];
370 		d = dst + len;
371 	} else
372 		d = dst + wcslen(dst);
373 
374 	if (flags & VIS_GLOB)
375 		for (s = char_glob; *s; *d++ = *s++)
376 			continue;
377 
378 	if (flags & VIS_SHELL)
379 		for (s = char_shell; *s; *d++ = *s++)
380 			continue;
381 
382 	if (flags & VIS_SP) *d++ = L' ';
383 	if (flags & VIS_TAB) *d++ = L'\t';
384 	if (flags & VIS_NL) *d++ = L'\n';
385 	if (flags & VIS_DQ) *d++ = L'"';
386 	if ((flags & VIS_NOSLASH) == 0) *d++ = L'\\';
387 	*d = L'\0';
388 
389 	return dst;
390 }
391 
392 /*
393  * istrsenvisx()
394  * 	The main internal function.
395  *	All user-visible functions call this one.
396  */
397 static int
398 istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
399     int flags, const char *mbextra, int *cerr_ptr)
400 {
401 	char mbbuf[MB_LEN_MAX];
402 	wchar_t *dst, *src, *pdst, *psrc, *start, *extra;
403 	size_t len, olen;
404 	uint64_t bmsk, wmsk;
405 	wint_t c;
406 	visfun_t f;
407 	int clen = 0, cerr, error = -1, i, shft;
408 	char *mbdst, *mbwrite, *mdst;
409 	size_t mbslength;
410 	size_t maxolen;
411 	mbstate_t mbstate;
412 
413 	_DIAGASSERT(mbdstp != NULL);
414 	_DIAGASSERT(mbsrc != NULL || mblength == 0);
415 	_DIAGASSERT(mbextra != NULL);
416 
417 	mbslength = mblength;
418 	/*
419 	 * When inputing a single character, must also read in the
420 	 * next character for nextc, the look-ahead character.
421 	 */
422 	if (mbslength == 1)
423 		mbslength++;
424 
425 	/*
426 	 * Input (mbsrc) is a char string considered to be multibyte
427 	 * characters.  The input loop will read this string pulling
428 	 * one character, possibly multiple bytes, from mbsrc and
429 	 * converting each to wchar_t in src.
430 	 *
431 	 * The vis conversion will be done using the wide char
432 	 * wchar_t string.
433 	 *
434 	 * This will then be converted back to a multibyte string to
435 	 * return to the caller.
436 	 */
437 
438 	/*
439 	 * Guarantee the arithmetic on input to calloc won't overflow.
440 	 */
441 	if (mbslength > (SIZE_MAX - 1)/16) {
442 		errno = ENOMEM;
443 		return -1;
444 	}
445 
446 	/* Allocate space for the wide char strings */
447 	psrc = pdst = extra = NULL;
448 	mdst = NULL;
449 	if ((psrc = calloc(mbslength + 1, sizeof(*psrc))) == NULL)
450 		return -1;
451 	if ((pdst = calloc((16 * mbslength) + 1, sizeof(*pdst))) == NULL)
452 		goto out;
453 	if (*mbdstp == NULL) {
454 		if ((mdst = calloc((16 * mbslength) + 1, sizeof(*mdst))) == NULL)
455 			goto out;
456 		*mbdstp = mdst;
457 	}
458 
459 	mbdst = *mbdstp;
460 	dst = pdst;
461 	src = psrc;
462 
463 	if (flags & VIS_NOLOCALE) {
464 		/* Do one byte at a time conversion */
465 		cerr = 1;
466 	} else {
467 		/* Use caller's multibyte conversion error flag. */
468 		cerr = cerr_ptr ? *cerr_ptr : 0;
469 	}
470 
471 	/*
472 	 * Input loop.
473 	 * Handle up to mblength characters (not bytes).  We do not
474 	 * stop at NULs because we may be processing a block of data
475 	 * that includes NULs.
476 	 */
477 	memset(&mbstate, 0, sizeof(mbstate));
478 	while (mbslength > 0) {
479 		/* Convert one multibyte character to wchar_t. */
480 		if (!cerr) {
481 			clen = mbrtowc(src, mbsrc,
482 			    (mbslength < MB_LEN_MAX
483 				? mbslength
484 				: MB_LEN_MAX),
485 			    &mbstate);
486 			assert(clen < 0 || (size_t)clen <= mbslength);
487 			assert(clen <= MB_LEN_MAX);
488 		}
489 		if (cerr || clen < 0) {
490 			/* Conversion error, process as a byte instead. */
491 			*src = (wint_t)(u_char)*mbsrc;
492 			clen = 1;
493 			cerr = 1;
494 		}
495 		if (clen == 0) {
496 			/*
497 			 * NUL in input gives 0 return value. process
498 			 * as single NUL byte and keep going.
499 			 */
500 			clen = 1;
501 		}
502 		/*
503 		 * Let n := MIN(mbslength, MB_LEN_MAX).  We have:
504 		 *
505 		 *	mbslength >= 1
506 		 *	mbrtowc(..., n, &mbstate) <= n,
507 		 *		by the contract of mbrtowc
508 		 *
509 		 *  clen is either
510 		 *  (a) mbrtowc(..., n, &mbstate), in which case
511 		 *      clen <= n <= mbslength; or
512 		 *  (b) 1, in which case clen = 1 <= mbslength.
513 		 */
514 		assert(clen > 0);
515 		assert((size_t)clen <= mbslength);
516 		/* Advance buffer character pointer. */
517 		src++;
518 		/* Advance input pointer by number of bytes read. */
519 		mbsrc += clen;
520 		/* Decrement input byte count. */
521 		mbslength -= clen;
522 	}
523 	len = src - psrc;
524 	src = psrc;
525 
526 	/*
527 	 * In the single character input case, we will have actually
528 	 * processed two characters, c and nextc.  Reset len back to
529 	 * just a single character.
530 	 */
531 	if (mblength < len)
532 		len = mblength;
533 
534 	/* Convert extra argument to list of characters for this mode. */
535 	extra = makeextralist(flags, mbextra);
536 	if (!extra) {
537 		if (dlen && *dlen == 0) {
538 			errno = ENOSPC;
539 			goto out;
540 		}
541 		*mbdst = '\0';	/* can't create extra, return "" */
542 		error = 0;
543 		goto out;
544 	}
545 
546 	/* Look up which processing function to call. */
547 	f = getvisfun(flags);
548 
549 	/*
550 	 * Main processing loop.
551 	 * Call do_Xvis processing function one character at a time
552 	 * with next character available for look-ahead.
553 	 */
554 	for (start = dst; len > 0; len--) {
555 		c = *src++;
556 		dst = (*f)(dst, c, flags, len >= 1 ? *src : L'\0', extra);
557 		if (dst == NULL) {
558 			errno = ENOSPC;
559 			goto out;
560 		}
561 	}
562 
563 	/* Terminate the string in the buffer. */
564 	*dst = L'\0';
565 
566 	/*
567 	 * Output loop.
568 	 * Convert wchar_t string back to multibyte output string.
569 	 * If we have hit a multi-byte conversion error on input,
570 	 * output byte-by-byte here.  Else use wctomb().
571 	 */
572 	len = wcslen(start);
573 	if (dlen) {
574 		maxolen = *dlen;
575 		if (maxolen == 0) {
576 			errno = ENOSPC;
577 			goto out;
578 		}
579 	} else {
580 		if (len > (SIZE_MAX - 1)/MB_LEN_MAX) {
581 			errno = ENOSPC;
582 			goto out;
583 		}
584 		maxolen = len*MB_LEN_MAX + 1;
585 	}
586 	olen = 0;
587 	memset(&mbstate, 0, sizeof(mbstate));
588 	for (dst = start; len > 0; len--) {
589 		if (!cerr) {
590 			/*
591 			 * If we have at least MB_CUR_MAX bytes in the buffer,
592 			 * we'll just do the conversion in-place into mbdst.  We
593 			 * need to be a little more conservative when we get to
594 			 * the end of the buffer, as we may not have MB_CUR_MAX
595 			 * bytes but we may not need it.
596 			 */
597 			if (maxolen - olen > MB_CUR_MAX)
598 				mbwrite = mbdst;
599 			else
600 				mbwrite = mbbuf;
601 			clen = wcrtomb(mbwrite, *dst, &mbstate);
602 			if (clen > 0 && mbwrite != mbdst) {
603 				/*
604 				 * Don't break past our output limit, noting
605 				 * that maxolen includes the nul terminator so
606 				 * we can't write past maxolen - 1 here.
607 				 */
608 				if (olen + clen >= maxolen) {
609 					errno = ENOSPC;
610 					goto out;
611 				}
612 
613 				memcpy(mbdst, mbwrite, clen);
614 			}
615 		}
616 		if (cerr || clen < 0) {
617 			/*
618 			 * Conversion error, process as a byte(s) instead.
619 			 * Examine each byte and higher-order bytes for
620 			 * data.  E.g.,
621 			 *	0x000000000000a264 -> a2 64
622 			 *	0x000000001f00a264 -> 1f 00 a2 64
623 			 */
624 			clen = 0;
625 			wmsk = 0;
626 			for (i = sizeof(wmsk) - 1; i >= 0; i--) {
627 				shft = i * NBBY;
628 				bmsk = (uint64_t)0xffLL << shft;
629 				wmsk |= bmsk;
630 				if ((*dst & wmsk) || i == 0) {
631 					if (olen + clen + 1 >= maxolen) {
632 						errno = ENOSPC;
633 						goto out;
634 					}
635 
636 					mbdst[clen++] = (char)(
637 					    (uint64_t)(*dst & bmsk) >>
638 					    shft);
639 				}
640 			}
641 			cerr = 1;
642 		}
643 
644 		/*
645 		 * We'll be dereferencing mbdst[clen] after this to write the
646 		 * nul terminator; the above paths should have checked for a
647 		 * possible overflow already.
648 		 */
649 		assert(olen + clen < maxolen);
650 
651 		/* Advance output pointer by number of bytes written. */
652 		mbdst += clen;
653 		/* Advance buffer character pointer. */
654 		dst++;
655 		/* Incrment output character count. */
656 		olen += clen;
657 	}
658 
659 	/* Terminate the output string. */
660 	assert(olen < maxolen);
661 	*mbdst = '\0';
662 
663 	if (flags & VIS_NOLOCALE) {
664 		/* Pass conversion error flag out. */
665 		if (cerr_ptr)
666 			*cerr_ptr = cerr;
667 	}
668 
669 	free(extra);
670 	free(pdst);
671 	free(psrc);
672 
673 	return (int)olen;
674 out:
675 	free(extra);
676 	free(pdst);
677 	free(psrc);
678 	free(mdst);
679 	return error;
680 }
681 
682 static int
683 istrsenvisxl(char **mbdstp, size_t *dlen, const char *mbsrc,
684     int flags, const char *mbextra, int *cerr_ptr)
685 {
686 	return istrsenvisx(mbdstp, dlen, mbsrc,
687 	    mbsrc != NULL ? strlen(mbsrc) : 0, flags, mbextra, cerr_ptr);
688 }
689 
690 #endif
691 
692 #if !HAVE_SVIS
693 /*
694  *	The "svis" variants all take an "extra" arg that is a pointer
695  *	to a NUL-terminated list of characters to be encoded, too.
696  *	These functions are useful e. g. to encode strings in such a
697  *	way so that they are not interpreted by a shell.
698  */
699 
700 char *
701 svis(char *mbdst, int c, int flags, int nextc, const char *mbextra)
702 {
703 	char cc[2];
704 	int ret;
705 
706 	cc[0] = c;
707 	cc[1] = nextc;
708 
709 	ret = istrsenvisx(&mbdst, NULL, cc, 1, flags, mbextra, NULL);
710 	if (ret < 0)
711 		return NULL;
712 	return mbdst + ret;
713 }
714 
715 char *
716 snvis(char *mbdst, size_t dlen, int c, int flags, int nextc, const char *mbextra)
717 {
718 	char cc[2];
719 	int ret;
720 
721 	cc[0] = c;
722 	cc[1] = nextc;
723 
724 	ret = istrsenvisx(&mbdst, &dlen, cc, 1, flags, mbextra, NULL);
725 	if (ret < 0)
726 		return NULL;
727 	return mbdst + ret;
728 }
729 
730 int
731 strsvis(char *mbdst, const char *mbsrc, int flags, const char *mbextra)
732 {
733 	return istrsenvisxl(&mbdst, NULL, mbsrc, flags, mbextra, NULL);
734 }
735 
736 int
737 strsnvis(char *mbdst, size_t dlen, const char *mbsrc, int flags, const char *mbextra)
738 {
739 	return istrsenvisxl(&mbdst, &dlen, mbsrc, flags, mbextra, NULL);
740 }
741 
742 int
743 strsvisx(char *mbdst, const char *mbsrc, size_t len, int flags, const char *mbextra)
744 {
745 	return istrsenvisx(&mbdst, NULL, mbsrc, len, flags, mbextra, NULL);
746 }
747 
748 int
749 strsnvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
750     const char *mbextra)
751 {
752 	return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, mbextra, NULL);
753 }
754 
755 int
756 strsenvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
757     const char *mbextra, int *cerr_ptr)
758 {
759 	return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, mbextra, cerr_ptr);
760 }
761 #endif
762 
763 #if !HAVE_VIS
764 /*
765  * vis - visually encode characters
766  */
767 char *
768 vis(char *mbdst, int c, int flags, int nextc)
769 {
770 	char cc[2];
771 	int ret;
772 
773 	cc[0] = c;
774 	cc[1] = nextc;
775 
776 	ret = istrsenvisx(&mbdst, NULL, cc, 1, flags, "", NULL);
777 	if (ret < 0)
778 		return NULL;
779 	return mbdst + ret;
780 }
781 
782 char *
783 nvis(char *mbdst, size_t dlen, int c, int flags, int nextc)
784 {
785 	char cc[2];
786 	int ret;
787 
788 	cc[0] = c;
789 	cc[1] = nextc;
790 
791 	ret = istrsenvisx(&mbdst, &dlen, cc, 1, flags, "", NULL);
792 	if (ret < 0)
793 		return NULL;
794 	return mbdst + ret;
795 }
796 
797 /*
798  * strvis - visually encode characters from src into dst
799  *
800  *	Dst must be 4 times the size of src to account for possible
801  *	expansion.  The length of dst, not including the trailing NULL,
802  *	is returned.
803  */
804 
805 int
806 strvis(char *mbdst, const char *mbsrc, int flags)
807 {
808 	return istrsenvisxl(&mbdst, NULL, mbsrc, flags, "", NULL);
809 }
810 
811 int
812 strnvis(char *mbdst, size_t dlen, const char *mbsrc, int flags)
813 {
814 	return istrsenvisxl(&mbdst, &dlen, mbsrc, flags, "", NULL);
815 }
816 
817 int
818 stravis(char **mbdstp, const char *mbsrc, int flags)
819 {
820 	*mbdstp = NULL;
821 	return istrsenvisxl(mbdstp, NULL, mbsrc, flags, "", NULL);
822 }
823 
824 /*
825  * strvisx - visually encode characters from src into dst
826  *
827  *	Dst must be 4 times the size of src to account for possible
828  *	expansion.  The length of dst, not including the trailing NULL,
829  *	is returned.
830  *
831  *	Strvisx encodes exactly len characters from src into dst.
832  *	This is useful for encoding a block of data.
833  */
834 
835 int
836 strvisx(char *mbdst, const char *mbsrc, size_t len, int flags)
837 {
838 	return istrsenvisx(&mbdst, NULL, mbsrc, len, flags, "", NULL);
839 }
840 
841 int
842 strnvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags)
843 {
844 	return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, "", NULL);
845 }
846 
847 int
848 strenvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
849     int *cerr_ptr)
850 {
851 	return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, "", cerr_ptr);
852 }
853 #endif
854