xref: /vim-8.2.3635/src/bufwrite.c (revision 95a9dd1e)
1 /* vi:set ts=8 sts=4 sw=4 noet:
2  *
3  * VIM - Vi IMproved	by Bram Moolenaar
4  *
5  * Do ":help uganda"  in Vim to read copying and usage conditions.
6  * Do ":help credits" in Vim to see a list of people who contributed.
7  * See README.txt for an overview of the Vim source code.
8  */
9 
10 /*
11  * bufwrite.c: functions for writing a buffer
12  */
13 
14 #include "vim.h"
15 
16 #if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
17 # include <utime.h>		// for struct utimbuf
18 #endif
19 
20 #define SMALLBUFSIZE	256	// size of emergency write buffer
21 
22 /*
23  * Structure to pass arguments from buf_write() to buf_write_bytes().
24  */
25 struct bw_info
26 {
27     int		bw_fd;		// file descriptor
28     char_u	*bw_buf;	// buffer with data to be written
29     int		bw_len;		// length of data
30     int		bw_flags;	// FIO_ flags
31 #ifdef FEAT_CRYPT
32     buf_T	*bw_buffer;	// buffer being written
33 #endif
34     char_u	bw_rest[CONV_RESTLEN]; // not converted bytes
35     int		bw_restlen;	// nr of bytes in bw_rest[]
36     int		bw_first;	// first write call
37     char_u	*bw_conv_buf;	// buffer for writing converted chars
38     size_t	bw_conv_buflen; // size of bw_conv_buf
39     int		bw_conv_error;	// set for conversion error
40     linenr_T	bw_conv_error_lnum;  // first line with error or zero
41     linenr_T	bw_start_lnum;  // line number at start of buffer
42 #ifdef USE_ICONV
43     iconv_t	bw_iconv_fd;	// descriptor for iconv() or -1
44 #endif
45 };
46 
47 /*
48  * Convert a Unicode character to bytes.
49  * Return TRUE for an error, FALSE when it's OK.
50  */
51     static int
52 ucs2bytes(
53     unsigned	c,		// in: character
54     char_u	**pp,		// in/out: pointer to result
55     int		flags)		// FIO_ flags
56 {
57     char_u	*p = *pp;
58     int		error = FALSE;
59     int		cc;
60 
61 
62     if (flags & FIO_UCS4)
63     {
64 	if (flags & FIO_ENDIAN_L)
65 	{
66 	    *p++ = c;
67 	    *p++ = (c >> 8);
68 	    *p++ = (c >> 16);
69 	    *p++ = (c >> 24);
70 	}
71 	else
72 	{
73 	    *p++ = (c >> 24);
74 	    *p++ = (c >> 16);
75 	    *p++ = (c >> 8);
76 	    *p++ = c;
77 	}
78     }
79     else if (flags & (FIO_UCS2 | FIO_UTF16))
80     {
81 	if (c >= 0x10000)
82 	{
83 	    if (flags & FIO_UTF16)
84 	    {
85 		// Make two words, ten bits of the character in each.  First
86 		// word is 0xd800 - 0xdbff, second one 0xdc00 - 0xdfff
87 		c -= 0x10000;
88 		if (c >= 0x100000)
89 		    error = TRUE;
90 		cc = ((c >> 10) & 0x3ff) + 0xd800;
91 		if (flags & FIO_ENDIAN_L)
92 		{
93 		    *p++ = cc;
94 		    *p++ = ((unsigned)cc >> 8);
95 		}
96 		else
97 		{
98 		    *p++ = ((unsigned)cc >> 8);
99 		    *p++ = cc;
100 		}
101 		c = (c & 0x3ff) + 0xdc00;
102 	    }
103 	    else
104 		error = TRUE;
105 	}
106 	if (flags & FIO_ENDIAN_L)
107 	{
108 	    *p++ = c;
109 	    *p++ = (c >> 8);
110 	}
111 	else
112 	{
113 	    *p++ = (c >> 8);
114 	    *p++ = c;
115 	}
116     }
117     else    // Latin1
118     {
119 	if (c >= 0x100)
120 	{
121 	    error = TRUE;
122 	    *p++ = 0xBF;
123 	}
124 	else
125 	    *p++ = c;
126     }
127 
128     *pp = p;
129     return error;
130 }
131 
132 /*
133  * Call write() to write a number of bytes to the file.
134  * Handles encryption and 'encoding' conversion.
135  *
136  * Return FAIL for failure, OK otherwise.
137  */
138     static int
139 buf_write_bytes(struct bw_info *ip)
140 {
141     int		wlen;
142     char_u	*buf = ip->bw_buf;	// data to write
143     int		len = ip->bw_len;	// length of data
144     int		flags = ip->bw_flags;	// extra flags
145 
146     // Skip conversion when writing the crypt magic number or the BOM.
147     if (!(flags & FIO_NOCONVERT))
148     {
149 	char_u		*p;
150 	unsigned	c;
151 	int		n;
152 
153 	if (flags & FIO_UTF8)
154 	{
155 	    // Convert latin1 in the buffer to UTF-8 in the file.
156 	    p = ip->bw_conv_buf;	// translate to buffer
157 	    for (wlen = 0; wlen < len; ++wlen)
158 		p += utf_char2bytes(buf[wlen], p);
159 	    buf = ip->bw_conv_buf;
160 	    len = (int)(p - ip->bw_conv_buf);
161 	}
162 	else if (flags & (FIO_UCS4 | FIO_UTF16 | FIO_UCS2 | FIO_LATIN1))
163 	{
164 	    // Convert UTF-8 bytes in the buffer to UCS-2, UCS-4, UTF-16 or
165 	    // Latin1 chars in the file.
166 	    if (flags & FIO_LATIN1)
167 		p = buf;	// translate in-place (can only get shorter)
168 	    else
169 		p = ip->bw_conv_buf;	// translate to buffer
170 	    for (wlen = 0; wlen < len; wlen += n)
171 	    {
172 		if (wlen == 0 && ip->bw_restlen != 0)
173 		{
174 		    int		l;
175 
176 		    // Use remainder of previous call.  Append the start of
177 		    // buf[] to get a full sequence.  Might still be too
178 		    // short!
179 		    l = CONV_RESTLEN - ip->bw_restlen;
180 		    if (l > len)
181 			l = len;
182 		    mch_memmove(ip->bw_rest + ip->bw_restlen, buf, (size_t)l);
183 		    n = utf_ptr2len_len(ip->bw_rest, ip->bw_restlen + l);
184 		    if (n > ip->bw_restlen + len)
185 		    {
186 			// We have an incomplete byte sequence at the end to
187 			// be written.  We can't convert it without the
188 			// remaining bytes.  Keep them for the next call.
189 			if (ip->bw_restlen + len > CONV_RESTLEN)
190 			    return FAIL;
191 			ip->bw_restlen += len;
192 			break;
193 		    }
194 		    if (n > 1)
195 			c = utf_ptr2char(ip->bw_rest);
196 		    else
197 			c = ip->bw_rest[0];
198 		    if (n >= ip->bw_restlen)
199 		    {
200 			n -= ip->bw_restlen;
201 			ip->bw_restlen = 0;
202 		    }
203 		    else
204 		    {
205 			ip->bw_restlen -= n;
206 			mch_memmove(ip->bw_rest, ip->bw_rest + n,
207 						      (size_t)ip->bw_restlen);
208 			n = 0;
209 		    }
210 		}
211 		else
212 		{
213 		    n = utf_ptr2len_len(buf + wlen, len - wlen);
214 		    if (n > len - wlen)
215 		    {
216 			// We have an incomplete byte sequence at the end to
217 			// be written.  We can't convert it without the
218 			// remaining bytes.  Keep them for the next call.
219 			if (len - wlen > CONV_RESTLEN)
220 			    return FAIL;
221 			ip->bw_restlen = len - wlen;
222 			mch_memmove(ip->bw_rest, buf + wlen,
223 						      (size_t)ip->bw_restlen);
224 			break;
225 		    }
226 		    if (n > 1)
227 			c = utf_ptr2char(buf + wlen);
228 		    else
229 			c = buf[wlen];
230 		}
231 
232 		if (ucs2bytes(c, &p, flags) && !ip->bw_conv_error)
233 		{
234 		    ip->bw_conv_error = TRUE;
235 		    ip->bw_conv_error_lnum = ip->bw_start_lnum;
236 		}
237 		if (c == NL)
238 		    ++ip->bw_start_lnum;
239 	    }
240 	    if (flags & FIO_LATIN1)
241 		len = (int)(p - buf);
242 	    else
243 	    {
244 		buf = ip->bw_conv_buf;
245 		len = (int)(p - ip->bw_conv_buf);
246 	    }
247 	}
248 
249 #ifdef MSWIN
250 	else if (flags & FIO_CODEPAGE)
251 	{
252 	    // Convert UTF-8 or codepage to UCS-2 and then to MS-Windows
253 	    // codepage.
254 	    char_u	*from;
255 	    size_t	fromlen;
256 	    char_u	*to;
257 	    int		u8c;
258 	    BOOL	bad = FALSE;
259 	    int		needed;
260 
261 	    if (ip->bw_restlen > 0)
262 	    {
263 		// Need to concatenate the remainder of the previous call and
264 		// the bytes of the current call.  Use the end of the
265 		// conversion buffer for this.
266 		fromlen = len + ip->bw_restlen;
267 		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
268 		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
269 		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
270 	    }
271 	    else
272 	    {
273 		from = buf;
274 		fromlen = len;
275 	    }
276 
277 	    to = ip->bw_conv_buf;
278 	    if (enc_utf8)
279 	    {
280 		// Convert from UTF-8 to UCS-2, to the start of the buffer.
281 		// The buffer has been allocated to be big enough.
282 		while (fromlen > 0)
283 		{
284 		    n = (int)utf_ptr2len_len(from, (int)fromlen);
285 		    if (n > (int)fromlen)	// incomplete byte sequence
286 			break;
287 		    u8c = utf_ptr2char(from);
288 		    *to++ = (u8c & 0xff);
289 		    *to++ = (u8c >> 8);
290 		    fromlen -= n;
291 		    from += n;
292 		}
293 
294 		// Copy remainder to ip->bw_rest[] to be used for the next
295 		// call.
296 		if (fromlen > CONV_RESTLEN)
297 		{
298 		    // weird overlong sequence
299 		    ip->bw_conv_error = TRUE;
300 		    return FAIL;
301 		}
302 		mch_memmove(ip->bw_rest, from, fromlen);
303 		ip->bw_restlen = (int)fromlen;
304 	    }
305 	    else
306 	    {
307 		// Convert from enc_codepage to UCS-2, to the start of the
308 		// buffer.  The buffer has been allocated to be big enough.
309 		ip->bw_restlen = 0;
310 		needed = MultiByteToWideChar(enc_codepage,
311 			     MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen,
312 								     NULL, 0);
313 		if (needed == 0)
314 		{
315 		    // When conversion fails there may be a trailing byte.
316 		    needed = MultiByteToWideChar(enc_codepage,
317 			 MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen - 1,
318 								     NULL, 0);
319 		    if (needed == 0)
320 		    {
321 			// Conversion doesn't work.
322 			ip->bw_conv_error = TRUE;
323 			return FAIL;
324 		    }
325 		    // Save the trailing byte for the next call.
326 		    ip->bw_rest[0] = from[fromlen - 1];
327 		    ip->bw_restlen = 1;
328 		}
329 		needed = MultiByteToWideChar(enc_codepage, MB_ERR_INVALID_CHARS,
330 				(LPCSTR)from, (int)(fromlen - ip->bw_restlen),
331 							  (LPWSTR)to, needed);
332 		if (needed == 0)
333 		{
334 		    // Safety check: Conversion doesn't work.
335 		    ip->bw_conv_error = TRUE;
336 		    return FAIL;
337 		}
338 		to += needed * 2;
339 	    }
340 
341 	    fromlen = to - ip->bw_conv_buf;
342 	    buf = to;
343 # ifdef CP_UTF8	// VC 4.1 doesn't define CP_UTF8
344 	    if (FIO_GET_CP(flags) == CP_UTF8)
345 	    {
346 		// Convert from UCS-2 to UTF-8, using the remainder of the
347 		// conversion buffer.  Fails when out of space.
348 		for (from = ip->bw_conv_buf; fromlen > 1; fromlen -= 2)
349 		{
350 		    u8c = *from++;
351 		    u8c += (*from++ << 8);
352 		    to += utf_char2bytes(u8c, to);
353 		    if (to + 6 >= ip->bw_conv_buf + ip->bw_conv_buflen)
354 		    {
355 			ip->bw_conv_error = TRUE;
356 			return FAIL;
357 		    }
358 		}
359 		len = (int)(to - buf);
360 	    }
361 	    else
362 # endif
363 	    {
364 		// Convert from UCS-2 to the codepage, using the remainder of
365 		// the conversion buffer.  If the conversion uses the default
366 		// character "0", the data doesn't fit in this encoding, so
367 		// fail.
368 		len = WideCharToMultiByte(FIO_GET_CP(flags), 0,
369 			(LPCWSTR)ip->bw_conv_buf, (int)fromlen / sizeof(WCHAR),
370 			(LPSTR)to, (int)(ip->bw_conv_buflen - fromlen), 0,
371 									&bad);
372 		if (bad)
373 		{
374 		    ip->bw_conv_error = TRUE;
375 		    return FAIL;
376 		}
377 	    }
378 	}
379 #endif
380 
381 #ifdef MACOS_CONVERT
382 	else if (flags & FIO_MACROMAN)
383 	{
384 	    // Convert UTF-8 or latin1 to Apple MacRoman.
385 	    char_u	*from;
386 	    size_t	fromlen;
387 
388 	    if (ip->bw_restlen > 0)
389 	    {
390 		// Need to concatenate the remainder of the previous call and
391 		// the bytes of the current call.  Use the end of the
392 		// conversion buffer for this.
393 		fromlen = len + ip->bw_restlen;
394 		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
395 		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
396 		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
397 	    }
398 	    else
399 	    {
400 		from = buf;
401 		fromlen = len;
402 	    }
403 
404 	    if (enc2macroman(from, fromlen,
405 			ip->bw_conv_buf, &len, ip->bw_conv_buflen,
406 			ip->bw_rest, &ip->bw_restlen) == FAIL)
407 	    {
408 		ip->bw_conv_error = TRUE;
409 		return FAIL;
410 	    }
411 	    buf = ip->bw_conv_buf;
412 	}
413 #endif
414 
415 #ifdef USE_ICONV
416 	if (ip->bw_iconv_fd != (iconv_t)-1)
417 	{
418 	    const char	*from;
419 	    size_t	fromlen;
420 	    char	*to;
421 	    size_t	tolen;
422 
423 	    // Convert with iconv().
424 	    if (ip->bw_restlen > 0)
425 	    {
426 		char *fp;
427 
428 		// Need to concatenate the remainder of the previous call and
429 		// the bytes of the current call.  Use the end of the
430 		// conversion buffer for this.
431 		fromlen = len + ip->bw_restlen;
432 		fp = (char *)ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
433 		mch_memmove(fp, ip->bw_rest, (size_t)ip->bw_restlen);
434 		mch_memmove(fp + ip->bw_restlen, buf, (size_t)len);
435 		from = fp;
436 		tolen = ip->bw_conv_buflen - fromlen;
437 	    }
438 	    else
439 	    {
440 		from = (const char *)buf;
441 		fromlen = len;
442 		tolen = ip->bw_conv_buflen;
443 	    }
444 	    to = (char *)ip->bw_conv_buf;
445 
446 	    if (ip->bw_first)
447 	    {
448 		size_t	save_len = tolen;
449 
450 		// output the initial shift state sequence
451 		(void)iconv(ip->bw_iconv_fd, NULL, NULL, &to, &tolen);
452 
453 		// There is a bug in iconv() on Linux (which appears to be
454 		// wide-spread) which sets "to" to NULL and messes up "tolen".
455 		if (to == NULL)
456 		{
457 		    to = (char *)ip->bw_conv_buf;
458 		    tolen = save_len;
459 		}
460 		ip->bw_first = FALSE;
461 	    }
462 
463 	    // If iconv() has an error or there is not enough room, fail.
464 	    if ((iconv(ip->bw_iconv_fd, (void *)&from, &fromlen, &to, &tolen)
465 			== (size_t)-1 && ICONV_ERRNO != ICONV_EINVAL)
466 						    || fromlen > CONV_RESTLEN)
467 	    {
468 		ip->bw_conv_error = TRUE;
469 		return FAIL;
470 	    }
471 
472 	    // copy remainder to ip->bw_rest[] to be used for the next call.
473 	    if (fromlen > 0)
474 		mch_memmove(ip->bw_rest, (void *)from, fromlen);
475 	    ip->bw_restlen = (int)fromlen;
476 
477 	    buf = ip->bw_conv_buf;
478 	    len = (int)((char_u *)to - ip->bw_conv_buf);
479 	}
480 #endif
481     }
482 
483     if (ip->bw_fd < 0)
484 	// Only checking conversion, which is OK if we get here.
485 	return OK;
486 
487 #ifdef FEAT_CRYPT
488     if (flags & FIO_ENCRYPTED)
489     {
490 	// Encrypt the data. Do it in-place if possible, otherwise use an
491 	// allocated buffer.
492 # ifdef CRYPT_NOT_INPLACE
493 	if (crypt_works_inplace(ip->bw_buffer->b_cryptstate))
494 	{
495 # endif
496 	    crypt_encode_inplace(ip->bw_buffer->b_cryptstate, buf, len);
497 # ifdef CRYPT_NOT_INPLACE
498 	}
499 	else
500 	{
501 	    char_u *outbuf;
502 
503 	    len = crypt_encode_alloc(curbuf->b_cryptstate, buf, len, &outbuf);
504 	    if (len == 0)
505 		return OK;  // Crypt layer is buffering, will flush later.
506 	    wlen = write_eintr(ip->bw_fd, outbuf, len);
507 	    vim_free(outbuf);
508 	    return (wlen < len) ? FAIL : OK;
509 	}
510 # endif
511     }
512 #endif
513 
514     wlen = write_eintr(ip->bw_fd, buf, len);
515     return (wlen < len) ? FAIL : OK;
516 }
517 
518 /*
519  * Check modification time of file, before writing to it.
520  * The size isn't checked, because using a tool like "gzip" takes care of
521  * using the same timestamp but can't set the size.
522  */
523     static int
524 check_mtime(buf_T *buf, stat_T *st)
525 {
526     if (buf->b_mtime_read != 0
527 	    && time_differs((long)st->st_mtime, buf->b_mtime_read))
528     {
529 	msg_scroll = TRUE;	    // don't overwrite messages here
530 	msg_silent = 0;		    // must give this prompt
531 	// don't use emsg() here, don't want to flush the buffers
532 	msg_attr(_("WARNING: The file has been changed since reading it!!!"),
533 						       HL_ATTR(HLF_E));
534 	if (ask_yesno((char_u *)_("Do you really want to write to it"),
535 								 TRUE) == 'n')
536 	    return FAIL;
537 	msg_scroll = FALSE;	    // always overwrite the file message now
538     }
539     return OK;
540 }
541 
542 /*
543  * Generate a BOM in "buf[4]" for encoding "name".
544  * Return the length of the BOM (zero when no BOM).
545  */
546     static int
547 make_bom(char_u *buf, char_u *name)
548 {
549     int		flags;
550     char_u	*p;
551 
552     flags = get_fio_flags(name);
553 
554     // Can't put a BOM in a non-Unicode file.
555     if (flags == FIO_LATIN1 || flags == 0)
556 	return 0;
557 
558     if (flags == FIO_UTF8)	// UTF-8
559     {
560 	buf[0] = 0xef;
561 	buf[1] = 0xbb;
562 	buf[2] = 0xbf;
563 	return 3;
564     }
565     p = buf;
566     (void)ucs2bytes(0xfeff, &p, flags);
567     return (int)(p - buf);
568 }
569 
570 #ifdef UNIX
571     static void
572 set_file_time(
573     char_u  *fname,
574     time_t  atime,	    // access time
575     time_t  mtime)	    // modification time
576 {
577 # if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
578     struct utimbuf  buf;
579 
580     buf.actime	= atime;
581     buf.modtime	= mtime;
582     (void)utime((char *)fname, &buf);
583 # else
584 #  if defined(HAVE_UTIMES)
585     struct timeval  tvp[2];
586 
587     tvp[0].tv_sec   = atime;
588     tvp[0].tv_usec  = 0;
589     tvp[1].tv_sec   = mtime;
590     tvp[1].tv_usec  = 0;
591 #   ifdef NeXT
592     (void)utimes((char *)fname, tvp);
593 #   else
594     (void)utimes((char *)fname, (const struct timeval *)&tvp);
595 #   endif
596 #  endif
597 # endif
598 }
599 #endif // UNIX
600 
601 /*
602  * buf_write() - write to file "fname" lines "start" through "end"
603  *
604  * We do our own buffering here because fwrite() is so slow.
605  *
606  * If "forceit" is true, we don't care for errors when attempting backups.
607  * In case of an error everything possible is done to restore the original
608  * file.  But when "forceit" is TRUE, we risk losing it.
609  *
610  * When "reset_changed" is TRUE and "append" == FALSE and "start" == 1 and
611  * "end" == curbuf->b_ml.ml_line_count, reset curbuf->b_changed.
612  *
613  * This function must NOT use NameBuff (because it's called by autowrite()).
614  *
615  * return FAIL for failure, OK otherwise
616  */
617     int
618 buf_write(
619     buf_T	    *buf,
620     char_u	    *fname,
621     char_u	    *sfname,
622     linenr_T	    start,
623     linenr_T	    end,
624     exarg_T	    *eap,		// for forced 'ff' and 'fenc', can be
625 					// NULL!
626     int		    append,		// append to the file
627     int		    forceit,
628     int		    reset_changed,
629     int		    filtering)
630 {
631     int		    fd;
632     char_u	    *backup = NULL;
633     int		    backup_copy = FALSE; // copy the original file?
634     int		    dobackup;
635     char_u	    *ffname;
636     char_u	    *wfname = NULL;	// name of file to write to
637     char_u	    *s;
638     char_u	    *ptr;
639     char_u	    c;
640     int		    len;
641     linenr_T	    lnum;
642     long	    nchars;
643     char_u	    *errmsg = NULL;
644     int		    errmsg_allocated = FALSE;
645     char_u	    *errnum = NULL;
646     char_u	    *buffer;
647     char_u	    smallbuf[SMALLBUFSIZE];
648     char_u	    *backup_ext;
649     int		    bufsize;
650     long	    perm;		    // file permissions
651     int		    retval = OK;
652     int		    newfile = FALSE;	    // TRUE if file doesn't exist yet
653     int		    msg_save = msg_scroll;
654     int		    overwriting;	    // TRUE if writing over original
655     int		    no_eol = FALSE;	    // no end-of-line written
656     int		    device = FALSE;	    // writing to a device
657     stat_T	    st_old;
658     int		    prev_got_int = got_int;
659     int		    checking_conversion;
660     int		    file_readonly = FALSE;  // overwritten file is read-only
661     static char	    *err_readonly = "is read-only (cannot override: \"W\" in 'cpoptions')";
662 #if defined(UNIX)			    // XXX fix me sometime?
663     int		    made_writable = FALSE;  // 'w' bit has been set
664 #endif
665 					// writing everything
666     int		    whole = (start == 1 && end == buf->b_ml.ml_line_count);
667     linenr_T	    old_line_count = buf->b_ml.ml_line_count;
668     int		    attr;
669     int		    fileformat;
670     int		    write_bin;
671     struct bw_info  write_info;		// info for buf_write_bytes()
672     int		    converted = FALSE;
673     int		    notconverted = FALSE;
674     char_u	    *fenc;		// effective 'fileencoding'
675     char_u	    *fenc_tofree = NULL; // allocated "fenc"
676     int		    wb_flags = 0;
677 #ifdef HAVE_ACL
678     vim_acl_T	    acl = NULL;		// ACL copied from original file to
679 					// backup or new file
680 #endif
681 #ifdef FEAT_PERSISTENT_UNDO
682     int		    write_undo_file = FALSE;
683     context_sha256_T sha_ctx;
684 #endif
685     unsigned int    bkc = get_bkc_value(buf);
686     pos_T	    orig_start = buf->b_op_start;
687     pos_T	    orig_end = buf->b_op_end;
688 
689     if (fname == NULL || *fname == NUL)	// safety check
690 	return FAIL;
691     if (buf->b_ml.ml_mfp == NULL)
692     {
693 	// This can happen during startup when there is a stray "w" in the
694 	// vimrc file.
695 	emsg(_(e_emptybuf));
696 	return FAIL;
697     }
698 
699     // Disallow writing from .exrc and .vimrc in current directory for
700     // security reasons.
701     if (check_secure())
702 	return FAIL;
703 
704     // Avoid a crash for a long name.
705     if (STRLEN(fname) >= MAXPATHL)
706     {
707 	emsg(_(e_longname));
708 	return FAIL;
709     }
710 
711     // must init bw_conv_buf and bw_iconv_fd before jumping to "fail"
712     write_info.bw_conv_buf = NULL;
713     write_info.bw_conv_error = FALSE;
714     write_info.bw_conv_error_lnum = 0;
715     write_info.bw_restlen = 0;
716 #ifdef USE_ICONV
717     write_info.bw_iconv_fd = (iconv_t)-1;
718 #endif
719 #ifdef FEAT_CRYPT
720     write_info.bw_buffer = buf;
721 #endif
722 
723     // After writing a file changedtick changes but we don't want to display
724     // the line.
725     ex_no_reprint = TRUE;
726 
727     // If there is no file name yet, use the one for the written file.
728     // BF_NOTEDITED is set to reflect this (in case the write fails).
729     // Don't do this when the write is for a filter command.
730     // Don't do this when appending.
731     // Only do this when 'cpoptions' contains the 'F' flag.
732     if (buf->b_ffname == NULL
733 	    && reset_changed
734 	    && whole
735 	    && buf == curbuf
736 #ifdef FEAT_QUICKFIX
737 	    && !bt_nofilename(buf)
738 #endif
739 	    && !filtering
740 	    && (!append || vim_strchr(p_cpo, CPO_FNAMEAPP) != NULL)
741 	    && vim_strchr(p_cpo, CPO_FNAMEW) != NULL)
742     {
743 	if (set_rw_fname(fname, sfname) == FAIL)
744 	    return FAIL;
745 	buf = curbuf;	    // just in case autocmds made "buf" invalid
746     }
747 
748     if (sfname == NULL)
749 	sfname = fname;
750     // For Unix: Use the short file name whenever possible.
751     // Avoids problems with networks and when directory names are changed.
752     // Don't do this for MS-DOS, a "cd" in a sub-shell may have moved us to
753     // another directory, which we don't detect
754     ffname = fname;			    // remember full fname
755 #ifdef UNIX
756     fname = sfname;
757 #endif
758 
759     if (buf->b_ffname != NULL && fnamecmp(ffname, buf->b_ffname) == 0)
760 	overwriting = TRUE;
761     else
762 	overwriting = FALSE;
763 
764     if (exiting)
765 	settmode(TMODE_COOK);	    // when exiting allow typeahead now
766 
767     ++no_wait_return;		    // don't wait for return yet
768 
769     // Set '[ and '] marks to the lines to be written.
770     buf->b_op_start.lnum = start;
771     buf->b_op_start.col = 0;
772     buf->b_op_end.lnum = end;
773     buf->b_op_end.col = 0;
774 
775     {
776 	aco_save_T	aco;
777 	int		buf_ffname = FALSE;
778 	int		buf_sfname = FALSE;
779 	int		buf_fname_f = FALSE;
780 	int		buf_fname_s = FALSE;
781 	int		did_cmd = FALSE;
782 	int		nofile_err = FALSE;
783 	int		empty_memline = (buf->b_ml.ml_mfp == NULL);
784 	bufref_T	bufref;
785 
786 	// Apply PRE autocommands.
787 	// Set curbuf to the buffer to be written.
788 	// Careful: The autocommands may call buf_write() recursively!
789 	if (ffname == buf->b_ffname)
790 	    buf_ffname = TRUE;
791 	if (sfname == buf->b_sfname)
792 	    buf_sfname = TRUE;
793 	if (fname == buf->b_ffname)
794 	    buf_fname_f = TRUE;
795 	if (fname == buf->b_sfname)
796 	    buf_fname_s = TRUE;
797 
798 	// set curwin/curbuf to buf and save a few things
799 	aucmd_prepbuf(&aco, buf);
800 	set_bufref(&bufref, buf);
801 
802 	if (append)
803 	{
804 	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEAPPENDCMD,
805 					 sfname, sfname, FALSE, curbuf, eap)))
806 	    {
807 #ifdef FEAT_QUICKFIX
808 		if (overwriting && bt_nofilename(curbuf))
809 		    nofile_err = TRUE;
810 		else
811 #endif
812 		    apply_autocmds_exarg(EVENT_FILEAPPENDPRE,
813 					  sfname, sfname, FALSE, curbuf, eap);
814 	    }
815 	}
816 	else if (filtering)
817 	{
818 	    apply_autocmds_exarg(EVENT_FILTERWRITEPRE,
819 					    NULL, sfname, FALSE, curbuf, eap);
820 	}
821 	else if (reset_changed && whole)
822 	{
823 	    int was_changed = curbufIsChanged();
824 
825 	    did_cmd = apply_autocmds_exarg(EVENT_BUFWRITECMD,
826 					  sfname, sfname, FALSE, curbuf, eap);
827 	    if (did_cmd)
828 	    {
829 		if (was_changed && !curbufIsChanged())
830 		{
831 		    // Written everything correctly and BufWriteCmd has reset
832 		    // 'modified': Correct the undo information so that an
833 		    // undo now sets 'modified'.
834 		    u_unchanged(curbuf);
835 		    u_update_save_nr(curbuf);
836 		}
837 	    }
838 	    else
839 	    {
840 #ifdef FEAT_QUICKFIX
841 		if (overwriting && bt_nofilename(curbuf))
842 		    nofile_err = TRUE;
843 		else
844 #endif
845 		    apply_autocmds_exarg(EVENT_BUFWRITEPRE,
846 					  sfname, sfname, FALSE, curbuf, eap);
847 	    }
848 	}
849 	else
850 	{
851 	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEWRITECMD,
852 					 sfname, sfname, FALSE, curbuf, eap)))
853 	    {
854 #ifdef FEAT_QUICKFIX
855 		if (overwriting && bt_nofilename(curbuf))
856 		    nofile_err = TRUE;
857 		else
858 #endif
859 		    apply_autocmds_exarg(EVENT_FILEWRITEPRE,
860 					  sfname, sfname, FALSE, curbuf, eap);
861 	    }
862 	}
863 
864 	// restore curwin/curbuf and a few other things
865 	aucmd_restbuf(&aco);
866 
867 	// In three situations we return here and don't write the file:
868 	// 1. the autocommands deleted or unloaded the buffer.
869 	// 2. The autocommands abort script processing.
870 	// 3. If one of the "Cmd" autocommands was executed.
871 	if (!bufref_valid(&bufref))
872 	    buf = NULL;
873 	if (buf == NULL || (buf->b_ml.ml_mfp == NULL && !empty_memline)
874 				       || did_cmd || nofile_err
875 #ifdef FEAT_EVAL
876 				       || aborting()
877 #endif
878 				       )
879 	{
880 	    if (buf != NULL && cmdmod.lockmarks)
881 	    {
882 		// restore the original '[ and '] positions
883 		buf->b_op_start = orig_start;
884 		buf->b_op_end = orig_end;
885 	    }
886 
887 	    --no_wait_return;
888 	    msg_scroll = msg_save;
889 	    if (nofile_err)
890 		emsg(_("E676: No matching autocommands for acwrite buffer"));
891 
892 	    if (nofile_err
893 #ifdef FEAT_EVAL
894 		    || aborting()
895 #endif
896 		    )
897 		// An aborting error, interrupt or exception in the
898 		// autocommands.
899 		return FAIL;
900 	    if (did_cmd)
901 	    {
902 		if (buf == NULL)
903 		    // The buffer was deleted.  We assume it was written
904 		    // (can't retry anyway).
905 		    return OK;
906 		if (overwriting)
907 		{
908 		    // Assume the buffer was written, update the timestamp.
909 		    ml_timestamp(buf);
910 		    if (append)
911 			buf->b_flags &= ~BF_NEW;
912 		    else
913 			buf->b_flags &= ~BF_WRITE_MASK;
914 		}
915 		if (reset_changed && buf->b_changed && !append
916 			&& (overwriting || vim_strchr(p_cpo, CPO_PLUS) != NULL))
917 		    // Buffer still changed, the autocommands didn't work
918 		    // properly.
919 		    return FAIL;
920 		return OK;
921 	    }
922 #ifdef FEAT_EVAL
923 	    if (!aborting())
924 #endif
925 		emsg(_("E203: Autocommands deleted or unloaded buffer to be written"));
926 	    return FAIL;
927 	}
928 
929 	// The autocommands may have changed the number of lines in the file.
930 	// When writing the whole file, adjust the end.
931 	// When writing part of the file, assume that the autocommands only
932 	// changed the number of lines that are to be written (tricky!).
933 	if (buf->b_ml.ml_line_count != old_line_count)
934 	{
935 	    if (whole)						// write all
936 		end = buf->b_ml.ml_line_count;
937 	    else if (buf->b_ml.ml_line_count > old_line_count)	// more lines
938 		end += buf->b_ml.ml_line_count - old_line_count;
939 	    else						// less lines
940 	    {
941 		end -= old_line_count - buf->b_ml.ml_line_count;
942 		if (end < start)
943 		{
944 		    --no_wait_return;
945 		    msg_scroll = msg_save;
946 		    emsg(_("E204: Autocommand changed number of lines in unexpected way"));
947 		    return FAIL;
948 		}
949 	    }
950 	}
951 
952 	// The autocommands may have changed the name of the buffer, which may
953 	// be kept in fname, ffname and sfname.
954 	if (buf_ffname)
955 	    ffname = buf->b_ffname;
956 	if (buf_sfname)
957 	    sfname = buf->b_sfname;
958 	if (buf_fname_f)
959 	    fname = buf->b_ffname;
960 	if (buf_fname_s)
961 	    fname = buf->b_sfname;
962     }
963 
964     if (cmdmod.lockmarks)
965     {
966 	// restore the original '[ and '] positions
967 	buf->b_op_start = orig_start;
968 	buf->b_op_end = orig_end;
969     }
970 
971 #ifdef FEAT_NETBEANS_INTG
972     if (netbeans_active() && isNetbeansBuffer(buf))
973     {
974 	if (whole)
975 	{
976 	    // b_changed can be 0 after an undo, but we still need to write
977 	    // the buffer to NetBeans.
978 	    if (buf->b_changed || isNetbeansModified(buf))
979 	    {
980 		--no_wait_return;		// may wait for return now
981 		msg_scroll = msg_save;
982 		netbeans_save_buffer(buf);	// no error checking...
983 		return retval;
984 	    }
985 	    else
986 	    {
987 		errnum = (char_u *)"E656: ";
988 		errmsg = (char_u *)_("NetBeans disallows writes of unmodified buffers");
989 		buffer = NULL;
990 		goto fail;
991 	    }
992 	}
993 	else
994 	{
995 	    errnum = (char_u *)"E657: ";
996 	    errmsg = (char_u *)_("Partial writes disallowed for NetBeans buffers");
997 	    buffer = NULL;
998 	    goto fail;
999 	}
1000     }
1001 #endif
1002 
1003     if (shortmess(SHM_OVER) && !exiting)
1004 	msg_scroll = FALSE;	    // overwrite previous file message
1005     else
1006 	msg_scroll = TRUE;	    // don't overwrite previous file message
1007     if (!filtering)
1008 	filemess(buf,
1009 #ifndef UNIX
1010 		sfname,
1011 #else
1012 		fname,
1013 #endif
1014 		    (char_u *)"", 0);	// show that we are busy
1015     msg_scroll = FALSE;		    // always overwrite the file message now
1016 
1017     buffer = alloc(WRITEBUFSIZE);
1018     if (buffer == NULL)		    // can't allocate big buffer, use small
1019 				    // one (to be able to write when out of
1020 				    // memory)
1021     {
1022 	buffer = smallbuf;
1023 	bufsize = SMALLBUFSIZE;
1024     }
1025     else
1026 	bufsize = WRITEBUFSIZE;
1027 
1028     // Get information about original file (if there is one).
1029 #if defined(UNIX)
1030     st_old.st_dev = 0;
1031     st_old.st_ino = 0;
1032     perm = -1;
1033     if (mch_stat((char *)fname, &st_old) < 0)
1034 	newfile = TRUE;
1035     else
1036     {
1037 	perm = st_old.st_mode;
1038 	if (!S_ISREG(st_old.st_mode))		// not a file
1039 	{
1040 	    if (S_ISDIR(st_old.st_mode))
1041 	    {
1042 		errnum = (char_u *)"E502: ";
1043 		errmsg = (char_u *)_("is a directory");
1044 		goto fail;
1045 	    }
1046 	    if (mch_nodetype(fname) != NODE_WRITABLE)
1047 	    {
1048 		errnum = (char_u *)"E503: ";
1049 		errmsg = (char_u *)_("is not a file or writable device");
1050 		goto fail;
1051 	    }
1052 	    // It's a device of some kind (or a fifo) which we can write to
1053 	    // but for which we can't make a backup.
1054 	    device = TRUE;
1055 	    newfile = TRUE;
1056 	    perm = -1;
1057 	}
1058     }
1059 #else // !UNIX
1060     // Check for a writable device name.
1061     c = mch_nodetype(fname);
1062     if (c == NODE_OTHER)
1063     {
1064 	errnum = (char_u *)"E503: ";
1065 	errmsg = (char_u *)_("is not a file or writable device");
1066 	goto fail;
1067     }
1068     if (c == NODE_WRITABLE)
1069     {
1070 # if defined(MSWIN)
1071 	// MS-Windows allows opening a device, but we will probably get stuck
1072 	// trying to write to it.
1073 	if (!p_odev)
1074 	{
1075 	    errnum = (char_u *)"E796: ";
1076 	    errmsg = (char_u *)_("writing to device disabled with 'opendevice' option");
1077 	    goto fail;
1078 	}
1079 # endif
1080 	device = TRUE;
1081 	newfile = TRUE;
1082 	perm = -1;
1083     }
1084     else
1085     {
1086 	perm = mch_getperm(fname);
1087 	if (perm < 0)
1088 	    newfile = TRUE;
1089 	else if (mch_isdir(fname))
1090 	{
1091 	    errnum = (char_u *)"E502: ";
1092 	    errmsg = (char_u *)_("is a directory");
1093 	    goto fail;
1094 	}
1095 	if (overwriting)
1096 	    (void)mch_stat((char *)fname, &st_old);
1097     }
1098 #endif // !UNIX
1099 
1100     if (!device && !newfile)
1101     {
1102 	// Check if the file is really writable (when renaming the file to
1103 	// make a backup we won't discover it later).
1104 	file_readonly = check_file_readonly(fname, (int)perm);
1105 
1106 	if (!forceit && file_readonly)
1107 	{
1108 	    if (vim_strchr(p_cpo, CPO_FWRITE) != NULL)
1109 	    {
1110 		errnum = (char_u *)"E504: ";
1111 		errmsg = (char_u *)_(err_readonly);
1112 	    }
1113 	    else
1114 	    {
1115 		errnum = (char_u *)"E505: ";
1116 		errmsg = (char_u *)_("is read-only (add ! to override)");
1117 	    }
1118 	    goto fail;
1119 	}
1120 
1121 	// Check if the timestamp hasn't changed since reading the file.
1122 	if (overwriting)
1123 	{
1124 	    retval = check_mtime(buf, &st_old);
1125 	    if (retval == FAIL)
1126 		goto fail;
1127 	}
1128     }
1129 
1130 #ifdef HAVE_ACL
1131     // For systems that support ACL: get the ACL from the original file.
1132     if (!newfile)
1133 	acl = mch_get_acl(fname);
1134 #endif
1135 
1136     // If 'backupskip' is not empty, don't make a backup for some files.
1137     dobackup = (p_wb || p_bk || *p_pm != NUL);
1138 #ifdef FEAT_WILDIGN
1139     if (dobackup && *p_bsk != NUL && match_file_list(p_bsk, sfname, ffname))
1140 	dobackup = FALSE;
1141 #endif
1142 
1143     // Save the value of got_int and reset it.  We don't want a previous
1144     // interruption cancel writing, only hitting CTRL-C while writing should
1145     // abort it.
1146     prev_got_int = got_int;
1147     got_int = FALSE;
1148 
1149     // Mark the buffer as 'being saved' to prevent changed buffer warnings
1150     buf->b_saving = TRUE;
1151 
1152     // If we are not appending or filtering, the file exists, and the
1153     // 'writebackup', 'backup' or 'patchmode' option is set, need a backup.
1154     // When 'patchmode' is set also make a backup when appending.
1155     //
1156     // Do not make any backup, if 'writebackup' and 'backup' are both switched
1157     // off.  This helps when editing large files on almost-full disks.
1158     if (!(append && *p_pm == NUL) && !filtering && perm >= 0 && dobackup)
1159     {
1160 #if defined(UNIX) || defined(MSWIN)
1161 	stat_T	    st;
1162 #endif
1163 
1164 	if ((bkc & BKC_YES) || append)	// "yes"
1165 	    backup_copy = TRUE;
1166 #if defined(UNIX) || defined(MSWIN)
1167 	else if ((bkc & BKC_AUTO))	// "auto"
1168 	{
1169 	    int		i;
1170 
1171 # ifdef UNIX
1172 	    // Don't rename the file when:
1173 	    // - it's a hard link
1174 	    // - it's a symbolic link
1175 	    // - we don't have write permission in the directory
1176 	    // - we can't set the owner/group of the new file
1177 	    if (st_old.st_nlink > 1
1178 		    || mch_lstat((char *)fname, &st) < 0
1179 		    || st.st_dev != st_old.st_dev
1180 		    || st.st_ino != st_old.st_ino
1181 #  ifndef HAVE_FCHOWN
1182 		    || st.st_uid != st_old.st_uid
1183 		    || st.st_gid != st_old.st_gid
1184 #  endif
1185 		    )
1186 		backup_copy = TRUE;
1187 	    else
1188 # else
1189 #  ifdef MSWIN
1190 	    // On NTFS file systems hard links are possible.
1191 	    if (mch_is_linked(fname))
1192 		backup_copy = TRUE;
1193 	    else
1194 #  endif
1195 # endif
1196 	    {
1197 		// Check if we can create a file and set the owner/group to
1198 		// the ones from the original file.
1199 		// First find a file name that doesn't exist yet (use some
1200 		// arbitrary numbers).
1201 		STRCPY(IObuff, fname);
1202 		for (i = 4913; ; i += 123)
1203 		{
1204 		    sprintf((char *)gettail(IObuff), "%d", i);
1205 		    if (mch_lstat((char *)IObuff, &st) < 0)
1206 			break;
1207 		}
1208 		fd = mch_open((char *)IObuff,
1209 				    O_CREAT|O_WRONLY|O_EXCL|O_NOFOLLOW, perm);
1210 		if (fd < 0)	// can't write in directory
1211 		    backup_copy = TRUE;
1212 		else
1213 		{
1214 # ifdef UNIX
1215 #  ifdef HAVE_FCHOWN
1216 		    vim_ignored = fchown(fd, st_old.st_uid, st_old.st_gid);
1217 #  endif
1218 		    if (mch_stat((char *)IObuff, &st) < 0
1219 			    || st.st_uid != st_old.st_uid
1220 			    || st.st_gid != st_old.st_gid
1221 			    || (long)st.st_mode != perm)
1222 			backup_copy = TRUE;
1223 # endif
1224 		    // Close the file before removing it, on MS-Windows we
1225 		    // can't delete an open file.
1226 		    close(fd);
1227 		    mch_remove(IObuff);
1228 # ifdef MSWIN
1229 		    // MS-Windows may trigger a virus scanner to open the
1230 		    // file, we can't delete it then.  Keep trying for half a
1231 		    // second.
1232 		    {
1233 			int try;
1234 
1235 			for (try = 0; try < 10; ++try)
1236 			{
1237 			    if (mch_lstat((char *)IObuff, &st) < 0)
1238 				break;
1239 			    ui_delay(50L, TRUE);  // wait 50 msec
1240 			    mch_remove(IObuff);
1241 			}
1242 		    }
1243 # endif
1244 		}
1245 	    }
1246 	}
1247 
1248 	// Break symlinks and/or hardlinks if we've been asked to.
1249 	if ((bkc & BKC_BREAKSYMLINK) || (bkc & BKC_BREAKHARDLINK))
1250 	{
1251 # ifdef UNIX
1252 	    int	lstat_res;
1253 
1254 	    lstat_res = mch_lstat((char *)fname, &st);
1255 
1256 	    // Symlinks.
1257 	    if ((bkc & BKC_BREAKSYMLINK)
1258 		    && lstat_res == 0
1259 		    && st.st_ino != st_old.st_ino)
1260 		backup_copy = FALSE;
1261 
1262 	    // Hardlinks.
1263 	    if ((bkc & BKC_BREAKHARDLINK)
1264 		    && st_old.st_nlink > 1
1265 		    && (lstat_res != 0 || st.st_ino == st_old.st_ino))
1266 		backup_copy = FALSE;
1267 # else
1268 #  if defined(MSWIN)
1269 	    // Symlinks.
1270 	    if ((bkc & BKC_BREAKSYMLINK) && mch_is_symbolic_link(fname))
1271 		backup_copy = FALSE;
1272 
1273 	    // Hardlinks.
1274 	    if ((bkc & BKC_BREAKHARDLINK) && mch_is_hard_link(fname))
1275 		backup_copy = FALSE;
1276 #  endif
1277 # endif
1278 	}
1279 
1280 #endif
1281 
1282 	// make sure we have a valid backup extension to use
1283 	if (*p_bex == NUL)
1284 	    backup_ext = (char_u *)".bak";
1285 	else
1286 	    backup_ext = p_bex;
1287 
1288 	if (backup_copy
1289 		&& (fd = mch_open((char *)fname, O_RDONLY | O_EXTRA, 0)) >= 0)
1290 	{
1291 	    int		bfd;
1292 	    char_u	*copybuf, *wp;
1293 	    int		some_error = FALSE;
1294 	    stat_T	st_new;
1295 	    char_u	*dirp;
1296 	    char_u	*rootname;
1297 #if defined(UNIX) || defined(MSWIN)
1298 	    char_u      *p;
1299 #endif
1300 #if defined(UNIX)
1301 	    int		did_set_shortname;
1302 	    mode_t	umask_save;
1303 #endif
1304 
1305 	    copybuf = alloc(WRITEBUFSIZE + 1);
1306 	    if (copybuf == NULL)
1307 	    {
1308 		some_error = TRUE;	    // out of memory
1309 		goto nobackup;
1310 	    }
1311 
1312 	    // Try to make the backup in each directory in the 'bdir' option.
1313 	    //
1314 	    // Unix semantics has it, that we may have a writable file,
1315 	    // that cannot be recreated with a simple open(..., O_CREAT, ) e.g:
1316 	    //  - the directory is not writable,
1317 	    //  - the file may be a symbolic link,
1318 	    //  - the file may belong to another user/group, etc.
1319 	    //
1320 	    // For these reasons, the existing writable file must be truncated
1321 	    // and reused. Creation of a backup COPY will be attempted.
1322 	    dirp = p_bdir;
1323 	    while (*dirp)
1324 	    {
1325 #ifdef UNIX
1326 		st_new.st_ino = 0;
1327 		st_new.st_dev = 0;
1328 		st_new.st_gid = 0;
1329 #endif
1330 
1331 		// Isolate one directory name, using an entry in 'bdir'.
1332 		(void)copy_option_part(&dirp, copybuf, WRITEBUFSIZE, ",");
1333 
1334 #if defined(UNIX) || defined(MSWIN)
1335 		p = copybuf + STRLEN(copybuf);
1336 		if (after_pathsep(copybuf, p) && p[-1] == p[-2])
1337 		    // Ends with '//', use full path
1338 		    if ((p = make_percent_swname(copybuf, fname)) != NULL)
1339 		    {
1340 			backup = modname(p, backup_ext, FALSE);
1341 			vim_free(p);
1342 		    }
1343 #endif
1344 		rootname = get_file_in_dir(fname, copybuf);
1345 		if (rootname == NULL)
1346 		{
1347 		    some_error = TRUE;	    // out of memory
1348 		    goto nobackup;
1349 		}
1350 
1351 #if defined(UNIX)
1352 		did_set_shortname = FALSE;
1353 #endif
1354 
1355 		// May try twice if 'shortname' not set.
1356 		for (;;)
1357 		{
1358 		    // Make the backup file name.
1359 		    if (backup == NULL)
1360 			backup = buf_modname((buf->b_p_sn || buf->b_shortname),
1361 						 rootname, backup_ext, FALSE);
1362 		    if (backup == NULL)
1363 		    {
1364 			vim_free(rootname);
1365 			some_error = TRUE;		// out of memory
1366 			goto nobackup;
1367 		    }
1368 
1369 		    // Check if backup file already exists.
1370 		    if (mch_stat((char *)backup, &st_new) >= 0)
1371 		    {
1372 #ifdef UNIX
1373 			// Check if backup file is same as original file.
1374 			// May happen when modname() gave the same file back.
1375 			// E.g. silly link, or file name-length reached.
1376 			// If we don't check here, we either ruin the file
1377 			// when copying or erase it after writing. jw.
1378 			if (st_new.st_dev == st_old.st_dev
1379 					    && st_new.st_ino == st_old.st_ino)
1380 			{
1381 			    VIM_CLEAR(backup);	// no backup file to delete
1382 			    // may try again with 'shortname' set
1383 			    if (!(buf->b_shortname || buf->b_p_sn))
1384 			    {
1385 				buf->b_shortname = TRUE;
1386 				did_set_shortname = TRUE;
1387 				continue;
1388 			    }
1389 				// setting shortname didn't help
1390 			    if (did_set_shortname)
1391 				buf->b_shortname = FALSE;
1392 			    break;
1393 			}
1394 #endif
1395 
1396 			// If we are not going to keep the backup file, don't
1397 			// delete an existing one, try to use another name.
1398 			// Change one character, just before the extension.
1399 			if (!p_bk)
1400 			{
1401 			    wp = backup + STRLEN(backup) - 1
1402 							 - STRLEN(backup_ext);
1403 			    if (wp < backup)	// empty file name ???
1404 				wp = backup;
1405 			    *wp = 'z';
1406 			    while (*wp > 'a'
1407 				    && mch_stat((char *)backup, &st_new) >= 0)
1408 				--*wp;
1409 			    // They all exist??? Must be something wrong.
1410 			    if (*wp == 'a')
1411 				VIM_CLEAR(backup);
1412 			}
1413 		    }
1414 		    break;
1415 		}
1416 		vim_free(rootname);
1417 
1418 		// Try to create the backup file
1419 		if (backup != NULL)
1420 		{
1421 		    // remove old backup, if present
1422 		    mch_remove(backup);
1423 		    // Open with O_EXCL to avoid the file being created while
1424 		    // we were sleeping (symlink hacker attack?). Reset umask
1425 		    // if possible to avoid mch_setperm() below.
1426 #ifdef UNIX
1427 		    umask_save = umask(0);
1428 #endif
1429 		    bfd = mch_open((char *)backup,
1430 				O_WRONLY|O_CREAT|O_EXTRA|O_EXCL|O_NOFOLLOW,
1431 								 perm & 0777);
1432 #ifdef UNIX
1433 		    (void)umask(umask_save);
1434 #endif
1435 		    if (bfd < 0)
1436 			VIM_CLEAR(backup);
1437 		    else
1438 		    {
1439 			// Set file protection same as original file, but
1440 			// strip s-bit.  Only needed if umask() wasn't used
1441 			// above.
1442 #ifndef UNIX
1443 			(void)mch_setperm(backup, perm & 0777);
1444 #else
1445 			// Try to set the group of the backup same as the
1446 			// original file. If this fails, set the protection
1447 			// bits for the group same as the protection bits for
1448 			// others.
1449 			if (st_new.st_gid != st_old.st_gid
1450 # ifdef HAVE_FCHOWN  // sequent-ptx lacks fchown()
1451 				&& fchown(bfd, (uid_t)-1, st_old.st_gid) != 0
1452 # endif
1453 						)
1454 			    mch_setperm(backup,
1455 					  (perm & 0707) | ((perm & 07) << 3));
1456 # if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
1457 			mch_copy_sec(fname, backup);
1458 # endif
1459 #endif
1460 
1461 			// copy the file.
1462 			write_info.bw_fd = bfd;
1463 			write_info.bw_buf = copybuf;
1464 			write_info.bw_flags = FIO_NOCONVERT;
1465 			while ((write_info.bw_len = read_eintr(fd, copybuf,
1466 							    WRITEBUFSIZE)) > 0)
1467 			{
1468 			    if (buf_write_bytes(&write_info) == FAIL)
1469 			    {
1470 				errmsg = (char_u *)_("E506: Can't write to backup file (add ! to override)");
1471 				break;
1472 			    }
1473 			    ui_breakcheck();
1474 			    if (got_int)
1475 			    {
1476 				errmsg = (char_u *)_(e_interr);
1477 				break;
1478 			    }
1479 			}
1480 
1481 			if (close(bfd) < 0 && errmsg == NULL)
1482 			    errmsg = (char_u *)_("E507: Close error for backup file (add ! to override)");
1483 			if (write_info.bw_len < 0)
1484 			    errmsg = (char_u *)_("E508: Can't read file for backup (add ! to override)");
1485 #ifdef UNIX
1486 			set_file_time(backup, st_old.st_atime, st_old.st_mtime);
1487 #endif
1488 #ifdef HAVE_ACL
1489 			mch_set_acl(backup, acl);
1490 #endif
1491 #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
1492 			mch_copy_sec(fname, backup);
1493 #endif
1494 			break;
1495 		    }
1496 		}
1497 	    }
1498     nobackup:
1499 	    close(fd);		// ignore errors for closing read file
1500 	    vim_free(copybuf);
1501 
1502 	    if (backup == NULL && errmsg == NULL)
1503 		errmsg = (char_u *)_("E509: Cannot create backup file (add ! to override)");
1504 	    // ignore errors when forceit is TRUE
1505 	    if ((some_error || errmsg != NULL) && !forceit)
1506 	    {
1507 		retval = FAIL;
1508 		goto fail;
1509 	    }
1510 	    errmsg = NULL;
1511 	}
1512 	else
1513 	{
1514 	    char_u	*dirp;
1515 	    char_u	*p;
1516 	    char_u	*rootname;
1517 
1518 	    // Make a backup by renaming the original file.
1519 
1520 	    // If 'cpoptions' includes the "W" flag, we don't want to
1521 	    // overwrite a read-only file.  But rename may be possible
1522 	    // anyway, thus we need an extra check here.
1523 	    if (file_readonly && vim_strchr(p_cpo, CPO_FWRITE) != NULL)
1524 	    {
1525 		errnum = (char_u *)"E504: ";
1526 		errmsg = (char_u *)_(err_readonly);
1527 		goto fail;
1528 	    }
1529 
1530 	    // Form the backup file name - change path/fo.o.h to
1531 	    // path/fo.o.h.bak Try all directories in 'backupdir', first one
1532 	    // that works is used.
1533 	    dirp = p_bdir;
1534 	    while (*dirp)
1535 	    {
1536 		// Isolate one directory name and make the backup file name.
1537 		(void)copy_option_part(&dirp, IObuff, IOSIZE, ",");
1538 
1539 #if defined(UNIX) || defined(MSWIN)
1540 		p = IObuff + STRLEN(IObuff);
1541 		if (after_pathsep(IObuff, p) && p[-1] == p[-2])
1542 		    // path ends with '//', use full path
1543 		    if ((p = make_percent_swname(IObuff, fname)) != NULL)
1544 		    {
1545 			backup = modname(p, backup_ext, FALSE);
1546 			vim_free(p);
1547 		    }
1548 #endif
1549 		if (backup == NULL)
1550 		{
1551 		    rootname = get_file_in_dir(fname, IObuff);
1552 		    if (rootname == NULL)
1553 			backup = NULL;
1554 		    else
1555 		    {
1556 			backup = buf_modname(
1557 				(buf->b_p_sn || buf->b_shortname),
1558 						rootname, backup_ext, FALSE);
1559 			vim_free(rootname);
1560 		    }
1561 		}
1562 
1563 		if (backup != NULL)
1564 		{
1565 		    // If we are not going to keep the backup file, don't
1566 		    // delete an existing one, try to use another name.
1567 		    // Change one character, just before the extension.
1568 		    if (!p_bk && mch_getperm(backup) >= 0)
1569 		    {
1570 			p = backup + STRLEN(backup) - 1 - STRLEN(backup_ext);
1571 			if (p < backup)	// empty file name ???
1572 			    p = backup;
1573 			*p = 'z';
1574 			while (*p > 'a' && mch_getperm(backup) >= 0)
1575 			    --*p;
1576 			// They all exist??? Must be something wrong!
1577 			if (*p == 'a')
1578 			    VIM_CLEAR(backup);
1579 		    }
1580 		}
1581 		if (backup != NULL)
1582 		{
1583 		    // Delete any existing backup and move the current version
1584 		    // to the backup.	For safety, we don't remove the backup
1585 		    // until the write has finished successfully. And if the
1586 		    // 'backup' option is set, leave it around.
1587 
1588 		    // If the renaming of the original file to the backup file
1589 		    // works, quit here.
1590 		    if (vim_rename(fname, backup) == 0)
1591 			break;
1592 
1593 		    VIM_CLEAR(backup);   // don't do the rename below
1594 		}
1595 	    }
1596 	    if (backup == NULL && !forceit)
1597 	    {
1598 		errmsg = (char_u *)_("E510: Can't make backup file (add ! to override)");
1599 		goto fail;
1600 	    }
1601 	}
1602     }
1603 
1604 #if defined(UNIX)
1605     // When using ":w!" and the file was read-only: make it writable
1606     if (forceit && perm >= 0 && !(perm & 0200) && st_old.st_uid == getuid()
1607 				     && vim_strchr(p_cpo, CPO_FWRITE) == NULL)
1608     {
1609 	perm |= 0200;
1610 	(void)mch_setperm(fname, perm);
1611 	made_writable = TRUE;
1612     }
1613 #endif
1614 
1615     // When using ":w!" and writing to the current file, 'readonly' makes no
1616     // sense, reset it, unless 'Z' appears in 'cpoptions'.
1617     if (forceit && overwriting && vim_strchr(p_cpo, CPO_KEEPRO) == NULL)
1618     {
1619 	buf->b_p_ro = FALSE;
1620 #ifdef FEAT_TITLE
1621 	need_maketitle = TRUE;	    // set window title later
1622 #endif
1623 	status_redraw_all();	    // redraw status lines later
1624     }
1625 
1626     if (end > buf->b_ml.ml_line_count)
1627 	end = buf->b_ml.ml_line_count;
1628     if (buf->b_ml.ml_flags & ML_EMPTY)
1629 	start = end + 1;
1630 
1631     // If the original file is being overwritten, there is a small chance that
1632     // we crash in the middle of writing. Therefore the file is preserved now.
1633     // This makes all block numbers positive so that recovery does not need
1634     // the original file.
1635     // Don't do this if there is a backup file and we are exiting.
1636     if (reset_changed && !newfile && overwriting
1637 					      && !(exiting && backup != NULL))
1638     {
1639 	ml_preserve(buf, FALSE);
1640 	if (got_int)
1641 	{
1642 	    errmsg = (char_u *)_(e_interr);
1643 	    goto restore_backup;
1644 	}
1645     }
1646 
1647 #ifdef VMS
1648     vms_remove_version(fname); // remove version
1649 #endif
1650     // Default: write the file directly.  May write to a temp file for
1651     // multi-byte conversion.
1652     wfname = fname;
1653 
1654     // Check for forced 'fileencoding' from "++opt=val" argument.
1655     if (eap != NULL && eap->force_enc != 0)
1656     {
1657 	fenc = eap->cmd + eap->force_enc;
1658 	fenc = enc_canonize(fenc);
1659 	fenc_tofree = fenc;
1660     }
1661     else
1662 	fenc = buf->b_p_fenc;
1663 
1664     // Check if the file needs to be converted.
1665     converted = need_conversion(fenc);
1666 
1667     // Check if UTF-8 to UCS-2/4 or Latin1 conversion needs to be done.  Or
1668     // Latin1 to Unicode conversion.  This is handled in buf_write_bytes().
1669     // Prepare the flags for it and allocate bw_conv_buf when needed.
1670     if (converted && (enc_utf8 || STRCMP(p_enc, "latin1") == 0))
1671     {
1672 	wb_flags = get_fio_flags(fenc);
1673 	if (wb_flags & (FIO_UCS2 | FIO_UCS4 | FIO_UTF16 | FIO_UTF8))
1674 	{
1675 	    // Need to allocate a buffer to translate into.
1676 	    if (wb_flags & (FIO_UCS2 | FIO_UTF16 | FIO_UTF8))
1677 		write_info.bw_conv_buflen = bufsize * 2;
1678 	    else // FIO_UCS4
1679 		write_info.bw_conv_buflen = bufsize * 4;
1680 	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
1681 	    if (write_info.bw_conv_buf == NULL)
1682 		end = 0;
1683 	}
1684     }
1685 
1686 #ifdef MSWIN
1687     if (converted && wb_flags == 0 && (wb_flags = get_win_fio_flags(fenc)) != 0)
1688     {
1689 	// Convert UTF-8 -> UCS-2 and UCS-2 -> DBCS.  Worst-case * 4:
1690 	write_info.bw_conv_buflen = bufsize * 4;
1691 	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
1692 	if (write_info.bw_conv_buf == NULL)
1693 	    end = 0;
1694     }
1695 #endif
1696 
1697 #ifdef MACOS_CONVERT
1698     if (converted && wb_flags == 0 && (wb_flags = get_mac_fio_flags(fenc)) != 0)
1699     {
1700 	write_info.bw_conv_buflen = bufsize * 3;
1701 	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
1702 	if (write_info.bw_conv_buf == NULL)
1703 	    end = 0;
1704     }
1705 #endif
1706 
1707 #if defined(FEAT_EVAL) || defined(USE_ICONV)
1708     if (converted && wb_flags == 0)
1709     {
1710 # ifdef USE_ICONV
1711 	// Use iconv() conversion when conversion is needed and it's not done
1712 	// internally.
1713 	write_info.bw_iconv_fd = (iconv_t)my_iconv_open(fenc,
1714 					enc_utf8 ? (char_u *)"utf-8" : p_enc);
1715 	if (write_info.bw_iconv_fd != (iconv_t)-1)
1716 	{
1717 	    // We're going to use iconv(), allocate a buffer to convert in.
1718 	    write_info.bw_conv_buflen = bufsize * ICONV_MULT;
1719 	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
1720 	    if (write_info.bw_conv_buf == NULL)
1721 		end = 0;
1722 	    write_info.bw_first = TRUE;
1723 	}
1724 #  ifdef FEAT_EVAL
1725 	else
1726 #  endif
1727 # endif
1728 
1729 # ifdef FEAT_EVAL
1730 	    // When the file needs to be converted with 'charconvert' after
1731 	    // writing, write to a temp file instead and let the conversion
1732 	    // overwrite the original file.
1733 	    if (*p_ccv != NUL)
1734 	    {
1735 		wfname = vim_tempname('w', FALSE);
1736 		if (wfname == NULL)	// Can't write without a tempfile!
1737 		{
1738 		    errmsg = (char_u *)_("E214: Can't find temp file for writing");
1739 		    goto restore_backup;
1740 		}
1741 	    }
1742 # endif
1743     }
1744 #endif
1745     if (converted && wb_flags == 0
1746 #ifdef USE_ICONV
1747 	    && write_info.bw_iconv_fd == (iconv_t)-1
1748 # endif
1749 # ifdef FEAT_EVAL
1750 	    && wfname == fname
1751 # endif
1752 	    )
1753     {
1754 	if (!forceit)
1755 	{
1756 	    errmsg = (char_u *)_("E213: Cannot convert (add ! to write without conversion)");
1757 	    goto restore_backup;
1758 	}
1759 	notconverted = TRUE;
1760     }
1761 
1762     // If conversion is taking place, we may first pretend to write and check
1763     // for conversion errors.  Then loop again to write for real.
1764     // When not doing conversion this writes for real right away.
1765     for (checking_conversion = TRUE; ; checking_conversion = FALSE)
1766     {
1767 	// There is no need to check conversion when:
1768 	// - there is no conversion
1769 	// - we make a backup file, that can be restored in case of conversion
1770 	//   failure.
1771 	if (!converted || dobackup)
1772 	    checking_conversion = FALSE;
1773 
1774 	if (checking_conversion)
1775 	{
1776 	    // Make sure we don't write anything.
1777 	    fd = -1;
1778 	    write_info.bw_fd = fd;
1779 	}
1780 	else
1781 	{
1782 #ifdef HAVE_FTRUNCATE
1783 # define TRUNC_ON_OPEN 0
1784 #else
1785 # define TRUNC_ON_OPEN O_TRUNC
1786 #endif
1787 	    // Open the file "wfname" for writing.
1788 	    // We may try to open the file twice: If we can't write to the file
1789 	    // and forceit is TRUE we delete the existing file and try to
1790 	    // create a new one. If this still fails we may have lost the
1791 	    // original file!  (this may happen when the user reached his
1792 	    // quotum for number of files).
1793 	    // Appending will fail if the file does not exist and forceit is
1794 	    // FALSE.
1795 	    while ((fd = mch_open((char *)wfname, O_WRONLY | O_EXTRA | (append
1796 				? (forceit ? (O_APPEND | O_CREAT) : O_APPEND)
1797 				: (O_CREAT | TRUNC_ON_OPEN))
1798 				, perm < 0 ? 0666 : (perm & 0777))) < 0)
1799 	    {
1800 		// A forced write will try to create a new file if the old one
1801 		// is still readonly. This may also happen when the directory
1802 		// is read-only. In that case the mch_remove() will fail.
1803 		if (errmsg == NULL)
1804 		{
1805 #ifdef UNIX
1806 		    stat_T	st;
1807 
1808 		    // Don't delete the file when it's a hard or symbolic link.
1809 		    if ((!newfile && st_old.st_nlink > 1)
1810 			    || (mch_lstat((char *)fname, &st) == 0
1811 				&& (st.st_dev != st_old.st_dev
1812 				    || st.st_ino != st_old.st_ino)))
1813 			errmsg = (char_u *)_("E166: Can't open linked file for writing");
1814 		    else
1815 #endif
1816 		    {
1817 			errmsg = (char_u *)_("E212: Can't open file for writing");
1818 			if (forceit && vim_strchr(p_cpo, CPO_FWRITE) == NULL
1819 								  && perm >= 0)
1820 			{
1821 #ifdef UNIX
1822 			    // we write to the file, thus it should be marked
1823 			    // writable after all
1824 			    if (!(perm & 0200))
1825 				made_writable = TRUE;
1826 			    perm |= 0200;
1827 			    if (st_old.st_uid != getuid()
1828 						  || st_old.st_gid != getgid())
1829 				perm &= 0777;
1830 #endif
1831 			    if (!append)  // don't remove when appending
1832 				mch_remove(wfname);
1833 			    continue;
1834 			}
1835 		    }
1836 		}
1837 
1838 restore_backup:
1839 		{
1840 		    stat_T	st;
1841 
1842 		    // If we failed to open the file, we don't need a backup.
1843 		    // Throw it away.  If we moved or removed the original file
1844 		    // try to put the backup in its place.
1845 		    if (backup != NULL && wfname == fname)
1846 		    {
1847 			if (backup_copy)
1848 			{
1849 			    // There is a small chance that we removed the
1850 			    // original, try to move the copy in its place.
1851 			    // This may not work if the vim_rename() fails.
1852 			    // In that case we leave the copy around.
1853 
1854 			    // If file does not exist, put the copy in its
1855 			    // place
1856 			    if (mch_stat((char *)fname, &st) < 0)
1857 				vim_rename(backup, fname);
1858 			    // if original file does exist throw away the copy
1859 			    if (mch_stat((char *)fname, &st) >= 0)
1860 				mch_remove(backup);
1861 			}
1862 			else
1863 			{
1864 			    // try to put the original file back
1865 			    vim_rename(backup, fname);
1866 			}
1867 		    }
1868 
1869 		    // if original file no longer exists give an extra warning
1870 		    if (!newfile && mch_stat((char *)fname, &st) < 0)
1871 			end = 0;
1872 		}
1873 
1874 		if (wfname != fname)
1875 		    vim_free(wfname);
1876 		goto fail;
1877 	    }
1878 	    write_info.bw_fd = fd;
1879 
1880 #if defined(UNIX)
1881 	    {
1882 		stat_T	st;
1883 
1884 		// Double check we are writing the intended file before making
1885 		// any changes.
1886 		if (overwriting
1887 			&& (!dobackup || backup_copy)
1888 			&& fname == wfname
1889 			&& perm >= 0
1890 			&& mch_fstat(fd, &st) == 0
1891 			&& st.st_ino != st_old.st_ino)
1892 		{
1893 		    close(fd);
1894 		    errmsg = (char_u *)_("E949: File changed while writing");
1895 		    goto fail;
1896 		}
1897 	    }
1898 #endif
1899 #ifdef HAVE_FTRUNCATE
1900 	    if (!append)
1901 		vim_ignored = ftruncate(fd, (off_t)0);
1902 #endif
1903 
1904 #if defined(MSWIN)
1905 	    if (backup != NULL && overwriting && !append)
1906 	    {
1907 		if (backup_copy)
1908 		    (void)mch_copy_file_attribute(wfname, backup);
1909 		else
1910 		    (void)mch_copy_file_attribute(backup, wfname);
1911 	    }
1912 
1913 	    if (!overwriting && !append)
1914 	    {
1915 		if (buf->b_ffname != NULL)
1916 		    (void)mch_copy_file_attribute(buf->b_ffname, wfname);
1917 		// Should copy resource fork
1918 	    }
1919 #endif
1920 
1921 #ifdef FEAT_CRYPT
1922 	    if (*buf->b_p_key != NUL && !filtering)
1923 	    {
1924 		char_u		*header;
1925 		int		header_len;
1926 
1927 		buf->b_cryptstate = crypt_create_for_writing(
1928 						      crypt_get_method_nr(buf),
1929 					   buf->b_p_key, &header, &header_len);
1930 		if (buf->b_cryptstate == NULL || header == NULL)
1931 		    end = 0;
1932 		else
1933 		{
1934 		    // Write magic number, so that Vim knows how this file is
1935 		    // encrypted when reading it back.
1936 		    write_info.bw_buf = header;
1937 		    write_info.bw_len = header_len;
1938 		    write_info.bw_flags = FIO_NOCONVERT;
1939 		    if (buf_write_bytes(&write_info) == FAIL)
1940 			end = 0;
1941 		    wb_flags |= FIO_ENCRYPTED;
1942 		    vim_free(header);
1943 		}
1944 	    }
1945 #endif
1946 	}
1947 	errmsg = NULL;
1948 
1949 	write_info.bw_buf = buffer;
1950 	nchars = 0;
1951 
1952 	// use "++bin", "++nobin" or 'binary'
1953 	if (eap != NULL && eap->force_bin != 0)
1954 	    write_bin = (eap->force_bin == FORCE_BIN);
1955 	else
1956 	    write_bin = buf->b_p_bin;
1957 
1958 	// The BOM is written just after the encryption magic number.
1959 	// Skip it when appending and the file already existed, the BOM only
1960 	// makes sense at the start of the file.
1961 	if (buf->b_p_bomb && !write_bin && (!append || perm < 0))
1962 	{
1963 	    write_info.bw_len = make_bom(buffer, fenc);
1964 	    if (write_info.bw_len > 0)
1965 	    {
1966 		// don't convert, do encryption
1967 		write_info.bw_flags = FIO_NOCONVERT | wb_flags;
1968 		if (buf_write_bytes(&write_info) == FAIL)
1969 		    end = 0;
1970 		else
1971 		    nchars += write_info.bw_len;
1972 	    }
1973 	}
1974 	write_info.bw_start_lnum = start;
1975 
1976 #ifdef FEAT_PERSISTENT_UNDO
1977 	write_undo_file = (buf->b_p_udf
1978 			    && overwriting
1979 			    && !append
1980 			    && !filtering
1981 			    && reset_changed
1982 			    && !checking_conversion);
1983 	if (write_undo_file)
1984 	    // Prepare for computing the hash value of the text.
1985 	    sha256_start(&sha_ctx);
1986 #endif
1987 
1988 	write_info.bw_len = bufsize;
1989 	write_info.bw_flags = wb_flags;
1990 	fileformat = get_fileformat_force(buf, eap);
1991 	s = buffer;
1992 	len = 0;
1993 	for (lnum = start; lnum <= end; ++lnum)
1994 	{
1995 	    // The next while loop is done once for each character written.
1996 	    // Keep it fast!
1997 	    ptr = ml_get_buf(buf, lnum, FALSE) - 1;
1998 #ifdef FEAT_PERSISTENT_UNDO
1999 	    if (write_undo_file)
2000 		sha256_update(&sha_ctx, ptr + 1,
2001 					      (UINT32_T)(STRLEN(ptr + 1) + 1));
2002 #endif
2003 	    while ((c = *++ptr) != NUL)
2004 	    {
2005 		if (c == NL)
2006 		    *s = NUL;		// replace newlines with NULs
2007 		else if (c == CAR && fileformat == EOL_MAC)
2008 		    *s = NL;		// Mac: replace CRs with NLs
2009 		else
2010 		    *s = c;
2011 		++s;
2012 		if (++len != bufsize)
2013 		    continue;
2014 		if (buf_write_bytes(&write_info) == FAIL)
2015 		{
2016 		    end = 0;		// write error: break loop
2017 		    break;
2018 		}
2019 		nchars += bufsize;
2020 		s = buffer;
2021 		len = 0;
2022 		write_info.bw_start_lnum = lnum;
2023 	    }
2024 	    // write failed or last line has no EOL: stop here
2025 	    if (end == 0
2026 		    || (lnum == end
2027 			&& (write_bin || !buf->b_p_fixeol)
2028 			&& (lnum == buf->b_no_eol_lnum
2029 			    || (lnum == buf->b_ml.ml_line_count
2030 							   && !buf->b_p_eol))))
2031 	    {
2032 		++lnum;			// written the line, count it
2033 		no_eol = TRUE;
2034 		break;
2035 	    }
2036 	    if (fileformat == EOL_UNIX)
2037 		*s++ = NL;
2038 	    else
2039 	    {
2040 		*s++ = CAR;		    // EOL_MAC or EOL_DOS: write CR
2041 		if (fileformat == EOL_DOS)  // write CR-NL
2042 		{
2043 		    if (++len == bufsize)
2044 		    {
2045 			if (buf_write_bytes(&write_info) == FAIL)
2046 			{
2047 			    end = 0;	// write error: break loop
2048 			    break;
2049 			}
2050 			nchars += bufsize;
2051 			s = buffer;
2052 			len = 0;
2053 		    }
2054 		    *s++ = NL;
2055 		}
2056 	    }
2057 	    if (++len == bufsize && end)
2058 	    {
2059 		if (buf_write_bytes(&write_info) == FAIL)
2060 		{
2061 		    end = 0;		// write error: break loop
2062 		    break;
2063 		}
2064 		nchars += bufsize;
2065 		s = buffer;
2066 		len = 0;
2067 
2068 		ui_breakcheck();
2069 		if (got_int)
2070 		{
2071 		    end = 0;		// Interrupted, break loop
2072 		    break;
2073 		}
2074 	    }
2075 #ifdef VMS
2076 	    // On VMS there is a problem: newlines get added when writing
2077 	    // blocks at a time. Fix it by writing a line at a time.
2078 	    // This is much slower!
2079 	    // Explanation: VAX/DECC RTL insists that records in some RMS
2080 	    // structures end with a newline (carriage return) character, and
2081 	    // if they don't it adds one.
2082 	    // With other RMS structures it works perfect without this fix.
2083 # ifndef MIN
2084 // Older DECC compiler for VAX doesn't define MIN()
2085 #  define MIN(a, b) ((a) < (b) ? (a) : (b))
2086 # endif
2087 	    if (buf->b_fab_rfm == FAB$C_VFC
2088 		    || ((buf->b_fab_rat & (FAB$M_FTN | FAB$M_CR)) != 0))
2089 	    {
2090 		int b2write;
2091 
2092 		buf->b_fab_mrs = (buf->b_fab_mrs == 0
2093 			? MIN(4096, bufsize)
2094 			: MIN(buf->b_fab_mrs, bufsize));
2095 
2096 		b2write = len;
2097 		while (b2write > 0)
2098 		{
2099 		    write_info.bw_len = MIN(b2write, buf->b_fab_mrs);
2100 		    if (buf_write_bytes(&write_info) == FAIL)
2101 		    {
2102 			end = 0;
2103 			break;
2104 		    }
2105 		    b2write -= MIN(b2write, buf->b_fab_mrs);
2106 		}
2107 		write_info.bw_len = bufsize;
2108 		nchars += len;
2109 		s = buffer;
2110 		len = 0;
2111 	    }
2112 #endif
2113 	}
2114 	if (len > 0 && end > 0)
2115 	{
2116 	    write_info.bw_len = len;
2117 	    if (buf_write_bytes(&write_info) == FAIL)
2118 		end = 0;		    // write error
2119 	    nchars += len;
2120 	}
2121 
2122 	// Stop when writing done or an error was encountered.
2123 	if (!checking_conversion || end == 0)
2124 	    break;
2125 
2126 	// If no error happened until now, writing should be ok, so loop to
2127 	// really write the buffer.
2128     }
2129 
2130     // If we started writing, finish writing. Also when an error was
2131     // encountered.
2132     if (!checking_conversion)
2133     {
2134 #if defined(UNIX) && defined(HAVE_FSYNC)
2135 	// On many journalling file systems there is a bug that causes both the
2136 	// original and the backup file to be lost when halting the system
2137 	// right after writing the file.  That's because only the meta-data is
2138 	// journalled.  Syncing the file slows down the system, but assures it
2139 	// has been written to disk and we don't lose it.
2140 	// For a device do try the fsync() but don't complain if it does not
2141 	// work (could be a pipe).
2142 	// If the 'fsync' option is FALSE, don't fsync().  Useful for laptops.
2143 	if (p_fs && vim_fsync(fd) != 0 && !device)
2144 	{
2145 	    errmsg = (char_u *)_(e_fsync);
2146 	    end = 0;
2147 	}
2148 #endif
2149 
2150 #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
2151 	// Probably need to set the security context.
2152 	if (!backup_copy)
2153 	    mch_copy_sec(backup, wfname);
2154 #endif
2155 
2156 #ifdef UNIX
2157 	// When creating a new file, set its owner/group to that of the
2158 	// original file.  Get the new device and inode number.
2159 	if (backup != NULL && !backup_copy)
2160 	{
2161 # ifdef HAVE_FCHOWN
2162 	    stat_T	st;
2163 
2164 	    // Don't change the owner when it's already OK, some systems remove
2165 	    // permission or ACL stuff.
2166 	    if (mch_stat((char *)wfname, &st) < 0
2167 		    || st.st_uid != st_old.st_uid
2168 		    || st.st_gid != st_old.st_gid)
2169 	    {
2170 		// changing owner might not be possible
2171 		vim_ignored = fchown(fd, st_old.st_uid, -1);
2172 		// if changing group fails clear the group permissions
2173 		if (fchown(fd, -1, st_old.st_gid) == -1 && perm > 0)
2174 		    perm &= ~070;
2175 	    }
2176 # endif
2177 	    buf_setino(buf);
2178 	}
2179 	else if (!buf->b_dev_valid)
2180 	    // Set the inode when creating a new file.
2181 	    buf_setino(buf);
2182 #endif
2183 
2184 #ifdef UNIX
2185 	if (made_writable)
2186 	    perm &= ~0200;	// reset 'w' bit for security reasons
2187 #endif
2188 #ifdef HAVE_FCHMOD
2189 	// set permission of new file same as old file
2190 	if (perm >= 0)
2191 	    (void)mch_fsetperm(fd, perm);
2192 #endif
2193 	if (close(fd) != 0)
2194 	{
2195 	    errmsg = (char_u *)_("E512: Close failed");
2196 	    end = 0;
2197 	}
2198 
2199 #ifndef HAVE_FCHMOD
2200 	// set permission of new file same as old file
2201 	if (perm >= 0)
2202 	    (void)mch_setperm(wfname, perm);
2203 #endif
2204 #ifdef HAVE_ACL
2205 	// Probably need to set the ACL before changing the user (can't set the
2206 	// ACL on a file the user doesn't own).
2207 	// On Solaris, with ZFS and the aclmode property set to "discard" (the
2208 	// default), chmod() discards all part of a file's ACL that don't
2209 	// represent the mode of the file.  It's non-trivial for us to discover
2210 	// whether we're in that situation, so we simply always re-set the ACL.
2211 # ifndef HAVE_SOLARIS_ZFS_ACL
2212 	if (!backup_copy)
2213 # endif
2214 	    mch_set_acl(wfname, acl);
2215 #endif
2216 #ifdef FEAT_CRYPT
2217 	if (buf->b_cryptstate != NULL)
2218 	{
2219 	    crypt_free_state(buf->b_cryptstate);
2220 	    buf->b_cryptstate = NULL;
2221 	}
2222 #endif
2223 
2224 #if defined(FEAT_EVAL)
2225 	if (wfname != fname)
2226 	{
2227 	    // The file was written to a temp file, now it needs to be
2228 	    // converted with 'charconvert' to (overwrite) the output file.
2229 	    if (end != 0)
2230 	    {
2231 		if (eval_charconvert(enc_utf8 ? (char_u *)"utf-8" : p_enc,
2232 						  fenc, wfname, fname) == FAIL)
2233 		{
2234 		    write_info.bw_conv_error = TRUE;
2235 		    end = 0;
2236 		}
2237 	    }
2238 	    mch_remove(wfname);
2239 	    vim_free(wfname);
2240 	}
2241 #endif
2242     }
2243 
2244     if (end == 0)
2245     {
2246 	// Error encountered.
2247 	if (errmsg == NULL)
2248 	{
2249 	    if (write_info.bw_conv_error)
2250 	    {
2251 		if (write_info.bw_conv_error_lnum == 0)
2252 		    errmsg = (char_u *)_("E513: write error, conversion failed (make 'fenc' empty to override)");
2253 		else
2254 		{
2255 		    errmsg_allocated = TRUE;
2256 		    errmsg = alloc(300);
2257 		    vim_snprintf((char *)errmsg, 300, _("E513: write error, conversion failed in line %ld (make 'fenc' empty to override)"),
2258 					 (long)write_info.bw_conv_error_lnum);
2259 		}
2260 	    }
2261 	    else if (got_int)
2262 		errmsg = (char_u *)_(e_interr);
2263 	    else
2264 		errmsg = (char_u *)_("E514: write error (file system full?)");
2265 	}
2266 
2267 	// If we have a backup file, try to put it in place of the new file,
2268 	// because the new file is probably corrupt.  This avoids losing the
2269 	// original file when trying to make a backup when writing the file a
2270 	// second time.
2271 	// When "backup_copy" is set we need to copy the backup over the new
2272 	// file.  Otherwise rename the backup file.
2273 	// If this is OK, don't give the extra warning message.
2274 	if (backup != NULL)
2275 	{
2276 	    if (backup_copy)
2277 	    {
2278 		// This may take a while, if we were interrupted let the user
2279 		// know we got the message.
2280 		if (got_int)
2281 		{
2282 		    msg(_(e_interr));
2283 		    out_flush();
2284 		}
2285 		if ((fd = mch_open((char *)backup, O_RDONLY | O_EXTRA, 0)) >= 0)
2286 		{
2287 		    if ((write_info.bw_fd = mch_open((char *)fname,
2288 				    O_WRONLY | O_CREAT | O_TRUNC | O_EXTRA,
2289 							   perm & 0777)) >= 0)
2290 		    {
2291 			// copy the file.
2292 			write_info.bw_buf = smallbuf;
2293 			write_info.bw_flags = FIO_NOCONVERT;
2294 			while ((write_info.bw_len = read_eintr(fd, smallbuf,
2295 						      SMALLBUFSIZE)) > 0)
2296 			    if (buf_write_bytes(&write_info) == FAIL)
2297 				break;
2298 
2299 			if (close(write_info.bw_fd) >= 0
2300 						   && write_info.bw_len == 0)
2301 			    end = 1;		// success
2302 		    }
2303 		    close(fd);	// ignore errors for closing read file
2304 		}
2305 	    }
2306 	    else
2307 	    {
2308 		if (vim_rename(backup, fname) == 0)
2309 		    end = 1;
2310 	    }
2311 	}
2312 	goto fail;
2313     }
2314 
2315     lnum -= start;	    // compute number of written lines
2316     --no_wait_return;	    // may wait for return now
2317 
2318 #if !(defined(UNIX) || defined(VMS))
2319     fname = sfname;	    // use shortname now, for the messages
2320 #endif
2321     if (!filtering)
2322     {
2323 	msg_add_fname(buf, fname);	// put fname in IObuff with quotes
2324 	c = FALSE;
2325 	if (write_info.bw_conv_error)
2326 	{
2327 	    STRCAT(IObuff, _(" CONVERSION ERROR"));
2328 	    c = TRUE;
2329 	    if (write_info.bw_conv_error_lnum != 0)
2330 		vim_snprintf_add((char *)IObuff, IOSIZE, _(" in line %ld;"),
2331 			(long)write_info.bw_conv_error_lnum);
2332 	}
2333 	else if (notconverted)
2334 	{
2335 	    STRCAT(IObuff, _("[NOT converted]"));
2336 	    c = TRUE;
2337 	}
2338 	else if (converted)
2339 	{
2340 	    STRCAT(IObuff, _("[converted]"));
2341 	    c = TRUE;
2342 	}
2343 	if (device)
2344 	{
2345 	    STRCAT(IObuff, _("[Device]"));
2346 	    c = TRUE;
2347 	}
2348 	else if (newfile)
2349 	{
2350 	    STRCAT(IObuff, shortmess(SHM_NEW) ? _("[New]") : _("[New File]"));
2351 	    c = TRUE;
2352 	}
2353 	if (no_eol)
2354 	{
2355 	    msg_add_eol();
2356 	    c = TRUE;
2357 	}
2358 	// may add [unix/dos/mac]
2359 	if (msg_add_fileformat(fileformat))
2360 	    c = TRUE;
2361 #ifdef FEAT_CRYPT
2362 	if (wb_flags & FIO_ENCRYPTED)
2363 	{
2364 	    crypt_append_msg(buf);
2365 	    c = TRUE;
2366 	}
2367 #endif
2368 	msg_add_lines(c, (long)lnum, nchars);	// add line/char count
2369 	if (!shortmess(SHM_WRITE))
2370 	{
2371 	    if (append)
2372 		STRCAT(IObuff, shortmess(SHM_WRI) ? _(" [a]") : _(" appended"));
2373 	    else
2374 		STRCAT(IObuff, shortmess(SHM_WRI) ? _(" [w]") : _(" written"));
2375 	}
2376 
2377 	set_keep_msg((char_u *)msg_trunc_attr((char *)IObuff, FALSE, 0), 0);
2378     }
2379 
2380     // When written everything correctly: reset 'modified'.  Unless not
2381     // writing to the original file and '+' is not in 'cpoptions'.
2382     if (reset_changed && whole && !append
2383 	    && !write_info.bw_conv_error
2384 	    && (overwriting || vim_strchr(p_cpo, CPO_PLUS) != NULL))
2385     {
2386 	unchanged(buf, TRUE, FALSE);
2387 	// b:changedtick is may be incremented in unchanged() but that
2388 	// should not trigger a TextChanged event.
2389 	if (buf->b_last_changedtick + 1 == CHANGEDTICK(buf))
2390 	    buf->b_last_changedtick = CHANGEDTICK(buf);
2391 	u_unchanged(buf);
2392 	u_update_save_nr(buf);
2393     }
2394 
2395     // If written to the current file, update the timestamp of the swap file
2396     // and reset the BF_WRITE_MASK flags. Also sets buf->b_mtime.
2397     if (overwriting)
2398     {
2399 	ml_timestamp(buf);
2400 	if (append)
2401 	    buf->b_flags &= ~BF_NEW;
2402 	else
2403 	    buf->b_flags &= ~BF_WRITE_MASK;
2404     }
2405 
2406     // If we kept a backup until now, and we are in patch mode, then we make
2407     // the backup file our 'original' file.
2408     if (*p_pm && dobackup)
2409     {
2410 	char *org = (char *)buf_modname((buf->b_p_sn || buf->b_shortname),
2411 							  fname, p_pm, FALSE);
2412 
2413 	if (backup != NULL)
2414 	{
2415 	    stat_T	st;
2416 
2417 	    // If the original file does not exist yet
2418 	    // the current backup file becomes the original file
2419 	    if (org == NULL)
2420 		emsg(_("E205: Patchmode: can't save original file"));
2421 	    else if (mch_stat(org, &st) < 0)
2422 	    {
2423 		vim_rename(backup, (char_u *)org);
2424 		VIM_CLEAR(backup);	    // don't delete the file
2425 #ifdef UNIX
2426 		set_file_time((char_u *)org, st_old.st_atime, st_old.st_mtime);
2427 #endif
2428 	    }
2429 	}
2430 	// If there is no backup file, remember that a (new) file was
2431 	// created.
2432 	else
2433 	{
2434 	    int empty_fd;
2435 
2436 	    if (org == NULL
2437 		    || (empty_fd = mch_open(org,
2438 				      O_CREAT | O_EXTRA | O_EXCL | O_NOFOLLOW,
2439 					perm < 0 ? 0666 : (perm & 0777))) < 0)
2440 	      emsg(_("E206: patchmode: can't touch empty original file"));
2441 	    else
2442 	      close(empty_fd);
2443 	}
2444 	if (org != NULL)
2445 	{
2446 	    mch_setperm((char_u *)org, mch_getperm(fname) & 0777);
2447 	    vim_free(org);
2448 	}
2449     }
2450 
2451     // Remove the backup unless 'backup' option is set or there was a
2452     // conversion error.
2453     if (!p_bk && backup != NULL && !write_info.bw_conv_error
2454 	    && mch_remove(backup) != 0)
2455 	emsg(_("E207: Can't delete backup file"));
2456 
2457     goto nofail;
2458 
2459     // Finish up.  We get here either after failure or success.
2460 fail:
2461     --no_wait_return;		// may wait for return now
2462 nofail:
2463 
2464     // Done saving, we accept changed buffer warnings again
2465     buf->b_saving = FALSE;
2466 
2467     vim_free(backup);
2468     if (buffer != smallbuf)
2469 	vim_free(buffer);
2470     vim_free(fenc_tofree);
2471     vim_free(write_info.bw_conv_buf);
2472 #ifdef USE_ICONV
2473     if (write_info.bw_iconv_fd != (iconv_t)-1)
2474     {
2475 	iconv_close(write_info.bw_iconv_fd);
2476 	write_info.bw_iconv_fd = (iconv_t)-1;
2477     }
2478 #endif
2479 #ifdef HAVE_ACL
2480     mch_free_acl(acl);
2481 #endif
2482 
2483     if (errmsg != NULL)
2484     {
2485 	int numlen = errnum != NULL ? (int)STRLEN(errnum) : 0;
2486 
2487 	attr = HL_ATTR(HLF_E);	// set highlight for error messages
2488 	msg_add_fname(buf,
2489 #ifndef UNIX
2490 		sfname
2491 #else
2492 		fname
2493 #endif
2494 		     );		// put file name in IObuff with quotes
2495 	if (STRLEN(IObuff) + STRLEN(errmsg) + numlen >= IOSIZE)
2496 	    IObuff[IOSIZE - STRLEN(errmsg) - numlen - 1] = NUL;
2497 	// If the error message has the form "is ...", put the error number in
2498 	// front of the file name.
2499 	if (errnum != NULL)
2500 	{
2501 	    STRMOVE(IObuff + numlen, IObuff);
2502 	    mch_memmove(IObuff, errnum, (size_t)numlen);
2503 	}
2504 	STRCAT(IObuff, errmsg);
2505 	emsg((char *)IObuff);
2506 	if (errmsg_allocated)
2507 	    vim_free(errmsg);
2508 
2509 	retval = FAIL;
2510 	if (end == 0)
2511 	{
2512 	    msg_puts_attr(_("\nWARNING: Original file may be lost or damaged\n"),
2513 		    attr | MSG_HIST);
2514 	    msg_puts_attr(_("don't quit the editor until the file is successfully written!"),
2515 		    attr | MSG_HIST);
2516 
2517 	    // Update the timestamp to avoid an "overwrite changed file"
2518 	    // prompt when writing again.
2519 	    if (mch_stat((char *)fname, &st_old) >= 0)
2520 	    {
2521 		buf_store_time(buf, &st_old, fname);
2522 		buf->b_mtime_read = buf->b_mtime;
2523 	    }
2524 	}
2525     }
2526     msg_scroll = msg_save;
2527 
2528 #ifdef FEAT_PERSISTENT_UNDO
2529     // When writing the whole file and 'undofile' is set, also write the undo
2530     // file.
2531     if (retval == OK && write_undo_file)
2532     {
2533 	char_u	    hash[UNDO_HASH_SIZE];
2534 
2535 	sha256_finish(&sha_ctx, hash);
2536 	u_write_undo(NULL, FALSE, buf, hash);
2537     }
2538 #endif
2539 
2540 #ifdef FEAT_EVAL
2541     if (!should_abort(retval))
2542 #else
2543     if (!got_int)
2544 #endif
2545     {
2546 	aco_save_T	aco;
2547 
2548 	curbuf->b_no_eol_lnum = 0;  // in case it was set by the previous read
2549 
2550 	// Apply POST autocommands.
2551 	// Careful: The autocommands may call buf_write() recursively!
2552 	aucmd_prepbuf(&aco, buf);
2553 
2554 	if (append)
2555 	    apply_autocmds_exarg(EVENT_FILEAPPENDPOST, fname, fname,
2556 							  FALSE, curbuf, eap);
2557 	else if (filtering)
2558 	    apply_autocmds_exarg(EVENT_FILTERWRITEPOST, NULL, fname,
2559 							  FALSE, curbuf, eap);
2560 	else if (reset_changed && whole)
2561 	    apply_autocmds_exarg(EVENT_BUFWRITEPOST, fname, fname,
2562 							  FALSE, curbuf, eap);
2563 	else
2564 	    apply_autocmds_exarg(EVENT_FILEWRITEPOST, fname, fname,
2565 							  FALSE, curbuf, eap);
2566 
2567 	// restore curwin/curbuf and a few other things
2568 	aucmd_restbuf(&aco);
2569 
2570 #ifdef FEAT_EVAL
2571 	if (aborting())	    // autocmds may abort script processing
2572 	    retval = FALSE;
2573 #endif
2574     }
2575 
2576     got_int |= prev_got_int;
2577 
2578     return retval;
2579 }
2580