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Date:: Mon Aug 1 13:47:24 2022 UTC
Message:: locate_hunk: set mangled earlier for clarity suggested by stsp@; no functional change.
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1 /*
2  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  *
16  * Apply patches.
17  *
18  * Things that we may want to support:
19  *     + support indented patches?
20  *     + support other kinds of patches?
21  */
22 
23 #include <sys/types.h>
24 #include <sys/queue.h>
25 #include <sys/socket.h>
26 #include <sys/stat.h>
27 #include <sys/uio.h>
28 
29 #include <ctype.h>
30 #include <errno.h>
31 #include <limits.h>
32 #include <sha1.h>
33 #include <stdint.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <imsg.h>
39 
40 #include "got_error.h"
41 #include "got_object.h"
42 #include "got_path.h"
43 #include "got_reference.h"
44 #include "got_cancel.h"
45 #include "got_worktree.h"
46 #include "got_repository.h"
47 #include "got_opentemp.h"
48 #include "got_patch.h"
49 #include "got_diff.h"
50 
51 #include "got_lib_delta.h"
52 #include "got_lib_diff.h"
53 #include "got_lib_object.h"
54 #include "got_lib_privsep.h"
55 #include "got_lib_sha1.h"
56 
57 #define MIN(a, b) ((a) < (b) ? (a) : (b))
58 
59 struct got_patch_hunk {
60 	STAILQ_ENTRY(got_patch_hunk) entries;
61 	const struct got_error *err;
62 	int	ws_mangled;
63 	int	offset;
64 	int	old_nonl;
65 	int	new_nonl;
66 	int	old_from;
67 	int	old_lines;
68 	int	new_from;
69 	int	new_lines;
70 	size_t	len;
71 	size_t	cap;
72 	char	**lines;
73 };
74 
75 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
76 struct got_patch {
77 	char	*old;
78 	char	*new;
79 	char	 cid[41];
80 	char	 blob[41];
81 	struct got_patch_hunk_head head;
82 };
83 
84 struct patch_args {
85 	got_patch_progress_cb progress_cb;
86 	void	*progress_arg;
87 	struct got_patch_hunk_head *head;
88 };
89 
90 static const struct got_error *
91 send_patch(struct imsgbuf *ibuf, int fd)
92 {
93 	const struct got_error *err = NULL;
94 
95 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
96 	    NULL, 0) == -1) {
97 		err = got_error_from_errno(
98 		    "imsg_compose GOT_IMSG_PATCH_FILE");
99 		close(fd);
100 		return err;
101 	}
102 
103 	return got_privsep_flush_imsg(ibuf);
104 }
105 
106 static void
107 patch_free(struct got_patch *p)
108 {
109 	struct got_patch_hunk *h;
110 	size_t i;
111 
112 	while (!STAILQ_EMPTY(&p->head)) {
113 		h = STAILQ_FIRST(&p->head);
114 		STAILQ_REMOVE_HEAD(&p->head, entries);
115 
116 		for (i = 0; i < h->len; ++i)
117 			free(h->lines[i]);
118 		free(h->lines);
119 		free(h);
120 	}
121 
122 	free(p->new);
123 	free(p->old);
124 
125 	memset(p, 0, sizeof(*p));
126 	STAILQ_INIT(&p->head);
127 }
128 
129 static const struct got_error *
130 pushline(struct got_patch_hunk *h, const char *line)
131 {
132 	void 	*t;
133 	size_t	 newcap;
134 
135 	if (h->len == h->cap) {
136 		if ((newcap = h->cap * 1.5) == 0)
137 			newcap = 16;
138 		t = recallocarray(h->lines, h->cap, newcap,
139 		    sizeof(h->lines[0]));
140 		if (t == NULL)
141 			return got_error_from_errno("recallocarray");
142 		h->lines = t;
143 		h->cap = newcap;
144 	}
145 
146 	if ((t = strdup(line)) == NULL)
147 		return got_error_from_errno("strdup");
148 
149 	h->lines[h->len++] = t;
150 	return NULL;
151 }
152 
153 static const struct got_error *
154 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
155 {
156 	const struct got_error *err = NULL;
157 	struct imsg imsg;
158 	struct got_imsg_patch_hunk hdr;
159 	struct got_imsg_patch patch;
160 	struct got_patch_hunk *h = NULL;
161 	size_t datalen;
162 	int lastmode = -1;
163 
164 	memset(p, 0, sizeof(*p));
165 	STAILQ_INIT(&p->head);
166 
167 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
168 	if (err)
169 		return err;
170 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
171 		*done = 1;
172 		goto done;
173 	}
174 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
175 		err = got_error(GOT_ERR_PRIVSEP_MSG);
176 		goto done;
177 	}
178 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
179 	if (datalen != sizeof(patch)) {
180 		err = got_error(GOT_ERR_PRIVSEP_LEN);
181 		goto done;
182 	}
183 	memcpy(&patch, imsg.data, sizeof(patch));
184 
185 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
186 	    patch.new[sizeof(patch.new)-1] != '\0' ||
187 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
188 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
189 		err = got_error(GOT_ERR_PRIVSEP_LEN);
190 		goto done;
191 	}
192 
193 	if (*patch.cid != '\0')
194 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
195 
196 	if (*patch.blob != '\0')
197 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
198 
199 	/* automatically set strip=1 for git-style diffs */
200 	if (strip == -1 && patch.git &&
201 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
202 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
203 		strip = 1;
204 
205 	/* prefer the new name if not /dev/null for not git-style diffs */
206 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
207 		err = got_path_strip(&p->old, patch.new, strip);
208 		if (err)
209 			goto done;
210 	} else if (*patch.old != '\0') {
211 		err = got_path_strip(&p->old, patch.old, strip);
212 		if (err)
213 			goto done;
214 	}
215 
216 	if (*patch.new != '\0') {
217 		err = got_path_strip(&p->new, patch.new, strip);
218 		if (err)
219 			goto done;
220 	}
221 
222 	if (p->old == NULL && p->new == NULL) {
223 		err = got_error(GOT_ERR_PATCH_MALFORMED);
224 		goto done;
225 	}
226 
227 	imsg_free(&imsg);
228 
229 	for (;;) {
230 		char *t;
231 
232 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
233 		if (err) {
234 			patch_free(p);
235 			return err;
236 		}
237 
238 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
239 		switch (imsg.hdr.type) {
240 		case GOT_IMSG_PATCH_DONE:
241 			if (h != NULL && h->len == 0)
242 				err = got_error(GOT_ERR_PATCH_MALFORMED);
243 			goto done;
244 		case GOT_IMSG_PATCH_HUNK:
245 			if (h != NULL &&
246 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
247 				err = got_error(GOT_ERR_PATCH_MALFORMED);
248 				goto done;
249 			}
250 			lastmode = -1;
251 			if (datalen != sizeof(hdr)) {
252 				err = got_error(GOT_ERR_PRIVSEP_LEN);
253 				goto done;
254 			}
255 			memcpy(&hdr, imsg.data, sizeof(hdr));
256 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
257 				err = got_error(GOT_ERR_PRIVSEP_LEN);
258 				goto done;
259 			}
260 			if ((h = calloc(1, sizeof(*h))) == NULL) {
261 				err = got_error_from_errno("calloc");
262 				goto done;
263 			}
264 			h->old_from = hdr.oldfrom;
265 			h->old_lines = hdr.oldlines;
266 			h->new_from = hdr.newfrom;
267 			h->new_lines = hdr.newlines;
268 			STAILQ_INSERT_TAIL(&p->head, h, entries);
269 			break;
270 		case GOT_IMSG_PATCH_LINE:
271 			if (h == NULL) {
272 				err = got_error(GOT_ERR_PRIVSEP_MSG);
273 				goto done;
274 			}
275 			t = imsg.data;
276 			/* at least one char */
277 			if (datalen < 2 || t[datalen-1] != '\0') {
278 				err = got_error(GOT_ERR_PRIVSEP_MSG);
279 				goto done;
280 			}
281 			if (*t != ' ' && *t != '-' && *t != '+' &&
282 			    *t != '\\') {
283 				err = got_error(GOT_ERR_PRIVSEP_MSG);
284 				goto done;
285 			}
286 
287 			if (*t != '\\')
288 				err = pushline(h, t);
289 			else if (lastmode == '-')
290 				h->old_nonl = 1;
291 			else if (lastmode == '+')
292 				h->new_nonl = 1;
293 			else
294 				err = got_error(GOT_ERR_PATCH_MALFORMED);
295 
296 			if (err)
297 				goto done;
298 
299 			lastmode = *t;
300 			break;
301 		default:
302 			err = got_error(GOT_ERR_PRIVSEP_MSG);
303 			goto done;
304 		}
305 
306 		imsg_free(&imsg);
307 	}
308 
309 done:
310 	if (err)
311 		patch_free(p);
312 
313 	imsg_free(&imsg);
314 	return err;
315 }
316 
317 static void
318 reverse_patch(struct got_patch *p)
319 {
320 	struct got_patch_hunk *h;
321 	size_t i;
322 	int tmp;
323 
324 	STAILQ_FOREACH(h, &p->head, entries) {
325 		tmp = h->old_from;
326 		h->old_from = h->new_from;
327 		h->new_from = tmp;
328 
329 		tmp = h->old_lines;
330 		h->old_lines = h->new_lines;
331 		h->new_lines = tmp;
332 
333 		tmp = h->old_nonl;
334 		h->old_nonl = h->new_nonl;
335 		h->new_nonl = tmp;
336 
337 		for (i = 0; i < h->len; ++i) {
338 			if (*h->lines[i] == '+')
339 				*h->lines[i] = '-';
340 			else if (*h->lines[i] == '-')
341 				*h->lines[i] = '+';
342 		}
343 	}
344 }
345 
346 /*
347  * Copy data from orig starting at copypos until pos into tmp.
348  * If pos is -1, copy until EOF.
349  */
350 static const struct got_error *
351 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
352 {
353 	char buf[BUFSIZ];
354 	size_t len, r, w;
355 
356 	if (fseeko(orig, copypos, SEEK_SET) == -1)
357 		return got_error_from_errno("fseeko");
358 
359 	while (pos == -1 || copypos < pos) {
360 		len = sizeof(buf);
361 		if (pos > 0)
362 			len = MIN(len, (size_t)pos - copypos);
363 		r = fread(buf, 1, len, orig);
364 		if (r != len && ferror(orig))
365 			return got_error_from_errno("fread");
366 		w = fwrite(buf, 1, r, tmp);
367 		if (w != r)
368 			return got_error_from_errno("fwrite");
369 		copypos += len;
370 		if (r != len && feof(orig)) {
371 			if (pos == -1)
372 				return NULL;
373 			return got_error(GOT_ERR_HUNK_FAILED);
374 		}
375 	}
376 	return NULL;
377 }
378 
379 static int linecmp(const char *, const char *, int *);
380 
381 static const struct got_error *
382 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
383 {
384 	const struct got_error *err = NULL;
385 	char *line = NULL;
386 	char mode = *h->lines[0];
387 	size_t linesize = 0;
388 	ssize_t linelen;
389 	off_t match = -1;
390 	int mangled = 0, match_lineno = -1;
391 
392 	for (;;) {
393 		linelen = getline(&line, &linesize, orig);
394 		if (linelen == -1) {
395 			if (ferror(orig))
396 				err = got_error_from_errno("getline");
397 			else if (match == -1)
398 				err = got_error(GOT_ERR_HUNK_FAILED);
399 			break;
400 		}
401 		if (line[linelen - 1] == '\n')
402 			line[linelen - 1] = '\0';
403 		(*lineno)++;
404 
405 		if ((mode == ' ' && !linecmp(h->lines[0] + 1, line, &mangled)) ||
406 		    (mode == '-' && !linecmp(h->lines[0] + 1, line, &mangled)) ||
407 		    (mode == '+' && *lineno == h->old_from)) {
408 			match = ftello(orig);
409 			if (match == -1) {
410 				err = got_error_from_errno("ftello");
411 				break;
412 			}
413 			match -= linelen;
414 			match_lineno = (*lineno)-1;
415 		}
416 
417 		if (*lineno >= h->old_from && match != -1) {
418 			if (mangled)
419 				h->ws_mangled = 1;
420 			break;
421 		}
422 	}
423 
424 	if (err == NULL) {
425 		*pos = match;
426 		*lineno = match_lineno;
427 		if (fseeko(orig, match, SEEK_SET) == -1)
428 			err = got_error_from_errno("fseeko");
429 	}
430 
431 	free(line);
432 	return err;
433 }
434 
435 static int
436 linecmp(const char *a, const char *b, int *mangled)
437 {
438 	int c;
439 
440 	*mangled = 0;
441 	c = strcmp(a, b);
442 	if (c == 0)
443 		return c;
444 
445 	*mangled = 1;
446 	for (;;) {
447 		while (*a == '\t' || *a == ' ' || *a == '\f')
448 			a++;
449 		while (*b == '\t' || *b == ' ' || *b == '\f')
450 			b++;
451 		if (*a == '\0' || *a != *b)
452 			break;
453 		a++, b++;
454 	}
455 
456 	return *a - *b;
457 }
458 
459 static const struct got_error *
460 test_hunk(FILE *orig, struct got_patch_hunk *h)
461 {
462 	const struct got_error *err = NULL;
463 	char *line = NULL;
464 	size_t linesize = 0, i = 0;
465 	ssize_t linelen;
466 	int mangled;
467 
468 	for (i = 0; i < h->len; ++i) {
469 		switch (*h->lines[i]) {
470 		case '+':
471 			continue;
472 		case ' ':
473 		case '-':
474 			linelen = getline(&line, &linesize, orig);
475 			if (linelen == -1) {
476 				if (ferror(orig))
477 					err = got_error_from_errno("getline");
478 				else
479 					err = got_error(
480 					    GOT_ERR_HUNK_FAILED);
481 				goto done;
482 			}
483 			if (line[linelen - 1] == '\n')
484 				line[linelen - 1] = '\0';
485 			if (linecmp(h->lines[i] + 1, line, &mangled)) {
486 				err = got_error(GOT_ERR_HUNK_FAILED);
487 				goto done;
488 			}
489 			if (mangled)
490 				h->ws_mangled = 1;
491 			break;
492 		}
493 	}
494 
495 done:
496 	free(line);
497 	return err;
498 }
499 
500 static const struct got_error *
501 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
502     off_t from)
503 {
504 	const struct got_error *err = NULL;
505 	const char *t;
506 	size_t linesize = 0, i, new = 0;
507 	char *line = NULL;
508 	char mode;
509 	ssize_t linelen;
510 
511 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
512 		return got_error_from_errno("fseeko");
513 
514 	for (i = 0; i < h->len; ++i) {
515 		switch (mode = *h->lines[i]) {
516 		case '-':
517 		case ' ':
518 			(*lineno)++;
519 			if (orig != NULL) {
520 				linelen = getline(&line, &linesize, orig);
521 				if (linelen == -1) {
522 					err = got_error_from_errno("getline");
523 					goto done;
524 				}
525 				if (line[linelen - 1] == '\n')
526 					line[linelen - 1] = '\0';
527 				t = line;
528 			} else
529 				t = h->lines[i] + 1;
530 			if (mode == '-')
531 				continue;
532 			if (fprintf(tmp, "%s\n", t) < 0) {
533 				err = got_error_from_errno("fprintf");
534 				goto done;
535 			}
536 			break;
537 		case '+':
538 			new++;
539 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0) {
540 				err = got_error_from_errno("fprintf");
541 				goto done;
542 			}
543 			if (new != h->new_lines || !h->new_nonl) {
544 				if (fprintf(tmp, "\n") < 0) {
545 					err = got_error_from_errno("fprintf");
546 					goto done;
547 				}
548 			}
549 			break;
550 		}
551 	}
552 
553 done:
554 	free(line);
555 	return err;
556 }
557 
558 static const struct got_error *
559 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
560 {
561 	const struct got_error *err = NULL;
562 	struct got_patch_hunk *h;
563 	struct stat sb;
564 	int lineno = 0;
565 	off_t copypos, pos;
566 	char *line = NULL;
567 	size_t linesize = 0;
568 	ssize_t linelen;
569 
570 	if (p->old == NULL) {				/* create */
571 		h = STAILQ_FIRST(&p->head);
572 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
573 			return got_error(GOT_ERR_PATCH_MALFORMED);
574 		return apply_hunk(orig, tmp, h, &lineno, 0);
575 	}
576 
577 	if (fstat(fileno(orig), &sb) == -1)
578 		return got_error_from_errno("fstat");
579 
580 	copypos = 0;
581 	STAILQ_FOREACH(h, &p->head, entries) {
582 	tryagain:
583 		err = locate_hunk(orig, h, &pos, &lineno);
584 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
585 			h->err = err;
586 		if (err != NULL)
587 			return err;
588 		err = copy(tmp, orig, copypos, pos);
589 		if (err != NULL)
590 			return err;
591 		copypos = pos;
592 
593 		err = test_hunk(orig, h);
594 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
595 			/*
596 			 * try to apply the hunk again starting the search
597 			 * after the previous partial match.
598 			 */
599 			if (fseeko(orig, pos, SEEK_SET) == -1)
600 				return got_error_from_errno("fseeko");
601 			linelen = getline(&line, &linesize, orig);
602 			if (linelen == -1)
603 				return got_error_from_errno("getline");
604 			lineno++;
605 			goto tryagain;
606 		}
607 		if (err != NULL)
608 			return err;
609 
610 		if (lineno + 1 != h->old_from)
611 			h->offset = lineno + 1 - h->old_from;
612 
613 		err = apply_hunk(orig, tmp, h, &lineno, pos);
614 		if (err != NULL)
615 			return err;
616 
617 		copypos = ftello(orig);
618 		if (copypos == -1)
619 			return got_error_from_errno("ftello");
620 	}
621 
622 	if (p->new == NULL && sb.st_size != copypos) {
623 		h = STAILQ_FIRST(&p->head);
624 		h->err = got_error(GOT_ERR_HUNK_FAILED);
625 		err = h->err;
626 	} else if (!feof(orig))
627 		err = copy(tmp, orig, copypos, -1);
628 
629 	return err;
630 }
631 
632 static const struct got_error *
633 report_progress(struct patch_args *pa, const char *old, const char *new,
634     unsigned char status, const struct got_error *orig_error)
635 {
636 	const struct got_error *err;
637 	struct got_patch_hunk *h;
638 
639 	err = pa->progress_cb(pa->progress_arg, old, new, status,
640 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
641 	if (err)
642 		return err;
643 
644 	STAILQ_FOREACH(h, pa->head, entries) {
645 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
646 			continue;
647 
648 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
649 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
650 		    h->offset, h->ws_mangled, h->err);
651 		if (err)
652 			return err;
653 	}
654 
655 	return NULL;
656 }
657 
658 static const struct got_error *
659 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
660     const char *path)
661 {
662 	return report_progress(arg, path, NULL, status, NULL);
663 }
664 
665 static const struct got_error *
666 patch_add(void *arg, unsigned char status, const char *path)
667 {
668 	return report_progress(arg, NULL, path, status, NULL);
669 }
670 
671 static const struct got_error *
672 open_blob(char **path, FILE **fp, const char *blobid,
673     struct got_repository *repo)
674 {
675 	const struct got_error *err = NULL;
676 	struct got_blob_object *blob = NULL;
677 	struct got_object_id id, *idptr, *matched_id = NULL;
678 	int fd = -1;
679 
680 	*fp = NULL;
681 	*path = NULL;
682 
683 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
684 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
685 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
686 		    repo);
687 		if (err)
688 			return err;
689 		idptr = matched_id;
690 	} else {
691 		if (!got_parse_sha1_digest(id.sha1, blobid))
692 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
693 		idptr = &id;
694 	}
695 
696 	fd = got_opentempfd();
697 	if (fd == -1) {
698 		err = got_error_from_errno("got_opentempfd");
699 		goto done;
700 	}
701 
702 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
703 	if (err)
704 		goto done;
705 
706 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
707 	if (err)
708 		goto done;
709 
710 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
711 	if (err)
712 		goto done;
713 
714 done:
715 	if (fd != -1 && close(fd) == -1 && err == NULL)
716 		err = got_error_from_errno("close");
717 	if (blob)
718 		got_object_blob_close(blob);
719 	if (matched_id != NULL)
720 		free(matched_id);
721 	if (err) {
722 		if (*fp != NULL)
723 			fclose(*fp);
724 		if (*path != NULL)
725 			unlink(*path);
726 		free(*path);
727 		*fp = NULL;
728 		*path = NULL;
729 	}
730 	return err;
731 }
732 
733 static const struct got_error *
734 prepare_merge(int *do_merge, char **apath, FILE **afile,
735     struct got_worktree *worktree, struct got_repository *repo,
736     struct got_patch *p, struct got_object_id *commit_id,
737     struct got_tree_object *tree, const char *path)
738 {
739 	const struct got_error *err = NULL;
740 
741 	*do_merge = 0;
742 	*apath = NULL;
743 	*afile = NULL;
744 
745 	/* don't run the diff3 merge on creations/deletions */
746 	if (p->old == NULL || p->new == NULL)
747 		return NULL;
748 
749 	if (commit_id) {
750 		struct got_object_id *id;
751 
752 		err = got_object_tree_find_path(&id, NULL, repo, tree, path);
753 		if (err)
754 			return err;
755 		got_sha1_digest_to_str(id->sha1, p->blob, sizeof(p->blob));
756 		got_sha1_digest_to_str(commit_id->sha1, p->cid, sizeof(p->cid));
757 		free(id);
758 		err = open_blob(apath, afile, p->blob, repo);
759 		*do_merge = err == NULL;
760 	} else if (*p->blob != '\0') {
761 		err = open_blob(apath, afile, p->blob, repo);
762 		/*
763 		 * ignore failures to open this blob, we might have
764 		 * parsed gibberish.
765 		 */
766 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
767 		    err->code != GOT_ERR_NO_OBJ)
768 			return err;
769 		*do_merge = err == NULL;
770 		err = NULL;
771 	}
772 
773 	return err;
774 }
775 
776 static const struct got_error *
777 apply_patch(int *overlapcnt, struct got_worktree *worktree,
778     struct got_repository *repo, struct got_fileindex *fileindex,
779     const char *old, const char *new, struct got_patch *p, int nop,
780     int reverse, struct got_object_id *commit_id,
781     struct got_tree_object *tree, struct patch_args *pa,
782     got_cancel_cb cancel_cb, void *cancel_arg)
783 {
784 	const struct got_error *err = NULL;
785 	struct stat sb;
786 	int do_merge = 0, file_renamed = 0;
787 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
788 	char *oldpath = NULL, *newpath = NULL;
789 	char *tmppath = NULL, *template = NULL, *parent = NULL;
790 	char *apath = NULL, *mergepath = NULL;
791 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
792 	int outfd;
793 	const char *outpath;
794 	mode_t mode = GOT_DEFAULT_FILE_MODE;
795 
796 	*overlapcnt = 0;
797 
798 	err = prepare_merge(&do_merge, &apath, &afile, worktree, repo, p,
799 	    commit_id, tree, old);
800 	if (err)
801 		return err;
802 
803 	if (reverse && !do_merge)
804 		reverse_patch(p);
805 
806 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
807 	    old) == -1) {
808 		err = got_error_from_errno("asprintf");
809 		goto done;
810 	}
811 
812 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
813 	    new) == -1) {
814 		err = got_error_from_errno("asprintf");
815 		goto done;
816 	}
817 
818 	file_renamed = strcmp(oldpath, newpath);
819 
820 	if (asprintf(&template, "%s/got-patch",
821 	    got_worktree_get_root_path(worktree)) == -1) {
822 		err = got_error_from_errno(template);
823 		goto done;
824 	}
825 
826 	if (p->old != NULL) {
827 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
828 			err = got_error_from_errno2("open", oldpath);
829 			goto done;
830 		}
831 		if (fstat(fileno(oldfile), &sb) == -1) {
832 			err = got_error_from_errno2("fstat", oldpath);
833 			goto done;
834 		}
835 		mode = sb.st_mode;
836 	}
837 
838 	err = got_opentemp_named(&tmppath, &tmpfile, template);
839 	if (err)
840 		goto done;
841 	outpath = tmppath;
842 	outfd = fileno(tmpfile);
843 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
844 	if (err)
845 		goto done;
846 
847 	if (do_merge) {
848 		const char *type, *id;
849 
850 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
851 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
852 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
853 			err = got_error_from_errno("fseeko");
854 			goto done;
855 		}
856 
857 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
858 			err = got_error_from_errno("asprintf");
859 			oldlabel = NULL;
860 			goto done;
861 		}
862 
863 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
864 			err = got_error_from_errno("asprintf");
865 			newlabel = NULL;
866 			goto done;
867 		}
868 
869 		if (*p->cid != '\0') {
870 			type = "commit";
871 			id = p->cid;
872 		} else {
873 			type = "blob";
874 			id = p->blob;
875 		}
876 
877 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
878 			err = got_error_from_errno("asprintf");
879 			anclabel = NULL;
880 			goto done;
881 		}
882 
883 		if (reverse) {
884 			char *s;
885 			FILE *t;
886 
887 			s = anclabel;
888 			anclabel = newlabel;
889 			newlabel = s;
890 
891 			t = afile;
892 			afile = tmpfile;
893 			tmpfile = t;
894 		}
895 
896 		err = got_opentemp_named(&mergepath, &mergefile, template);
897 		if (err)
898 			goto done;
899 		outpath = mergepath;
900 		outfd = fileno(mergefile);
901 
902 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
903 		    oldfile, oldlabel, anclabel, newlabel,
904 		    GOT_DIFF_ALGORITHM_PATIENCE);
905 		if (err)
906 			goto done;
907 	}
908 
909 	if (nop)
910 		goto done;
911 
912 	if (p->old != NULL && p->new == NULL) {
913 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
914 		    fileindex, patch_delete, pa);
915 		goto done;
916 	}
917 
918 	if (fchmod(outfd, mode) == -1) {
919 		err = got_error_from_errno2("chmod", tmppath);
920 		goto done;
921 	}
922 
923 	if (rename(outpath, newpath) == -1) {
924 		if (errno != ENOENT) {
925 			err = got_error_from_errno3("rename", outpath,
926 			    newpath);
927 			goto done;
928 		}
929 
930 		err = got_path_dirname(&parent, newpath);
931 		if (err != NULL)
932 			goto done;
933 		err = got_path_mkdir(parent);
934 		if (err != NULL)
935 			goto done;
936 		if (rename(outpath, newpath) == -1) {
937 			err = got_error_from_errno3("rename", outpath,
938 			    newpath);
939 			goto done;
940 		}
941 	}
942 
943 	if (file_renamed) {
944 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
945 		    fileindex, patch_delete, pa);
946 		if (err == NULL)
947 			err = got_worktree_patch_schedule_add(new, repo,
948 			    worktree, fileindex, patch_add,
949 			    pa);
950 		if (err)
951 			unlink(newpath);
952 	} else if (p->old == NULL) {
953 		err = got_worktree_patch_schedule_add(new, repo, worktree,
954 		    fileindex, patch_add, pa);
955 		if (err)
956 			unlink(newpath);
957 	} else if (*overlapcnt != 0)
958 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
959 	else if (do_merge)
960 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
961 	else
962 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
963 
964 done:
965 	free(parent);
966 	free(template);
967 
968 	if (tmppath != NULL)
969 		unlink(tmppath);
970 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
971 		err = got_error_from_errno("fclose");
972 	free(tmppath);
973 
974 	free(oldpath);
975 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
976 		err = got_error_from_errno("fclose");
977 
978 	if (apath != NULL)
979 		unlink(apath);
980 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
981 		err = got_error_from_errno("fclose");
982 	free(apath);
983 
984 	if (mergepath != NULL)
985 		unlink(mergepath);
986 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
987 		err = got_error_from_errno("fclose");
988 	free(mergepath);
989 
990 	free(newpath);
991 	free(oldlabel);
992 	free(newlabel);
993 	free(anclabel);
994 	return err;
995 }
996 
997 const struct got_error *
998 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
999     int nop, int strip, int reverse, struct got_object_id *commit_id,
1000     got_patch_progress_cb progress_cb, void *progress_arg,
1001     got_cancel_cb cancel_cb, void *cancel_arg)
1002 {
1003 	const struct got_error *err = NULL, *complete_err = NULL;
1004 	struct got_fileindex *fileindex = NULL;
1005 	struct got_commit_object *commit = NULL;
1006 	struct got_tree_object *tree = NULL;
1007 	char *fileindex_path = NULL;
1008 	char *oldpath, *newpath;
1009 	struct imsgbuf *ibuf;
1010 	int imsg_fds[2] = {-1, -1};
1011 	int overlapcnt, done = 0, failed = 0;
1012 	pid_t pid;
1013 
1014 	ibuf = calloc(1, sizeof(*ibuf));
1015 	if (ibuf == NULL) {
1016 		err = got_error_from_errno("calloc");
1017 		goto done;
1018 	}
1019 
1020 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1021 		err = got_error_from_errno("socketpair");
1022 		goto done;
1023 	}
1024 
1025 	pid = fork();
1026 	if (pid == -1) {
1027 		err = got_error_from_errno("fork");
1028 		goto done;
1029 	} else if (pid == 0) {
1030 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
1031 		    NULL);
1032 		/* not reached */
1033 	}
1034 
1035 	if (close(imsg_fds[1]) == -1) {
1036 		err = got_error_from_errno("close");
1037 		goto done;
1038 	}
1039 	imsg_fds[1] = -1;
1040 	imsg_init(ibuf, imsg_fds[0]);
1041 
1042 	err = send_patch(ibuf, fd);
1043 	fd = -1;
1044 	if (err)
1045 		goto done;
1046 
1047 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
1048 	    worktree);
1049 	if (err)
1050 		goto done;
1051 
1052 	if (commit_id) {
1053 		err = got_object_open_as_commit(&commit, repo, commit_id);
1054 		if (err)
1055 			goto done;
1056 
1057 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1058 		if (err)
1059 			goto done;
1060 	}
1061 
1062 	while (!done && err == NULL) {
1063 		struct got_patch p;
1064 		struct patch_args pa;
1065 
1066 		pa.progress_cb = progress_cb;
1067 		pa.progress_arg = progress_arg;
1068 		pa.head = &p.head;
1069 
1070 		err = recv_patch(ibuf, &done, &p, strip);
1071 		if (err || done)
1072 			break;
1073 
1074 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1075 		    &newpath, worktree, repo, fileindex);
1076 		if (err == NULL)
1077 			err = apply_patch(&overlapcnt, worktree, repo,
1078 			    fileindex, oldpath, newpath, &p, nop, reverse,
1079 			    commit_id, tree, &pa, cancel_cb, cancel_arg);
1080 		if (err != NULL) {
1081 			failed = 1;
1082 			/* recoverable errors */
1083 			if (err->code == GOT_ERR_FILE_STATUS ||
1084 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1085 				err = report_progress(&pa, p.old, p.new,
1086 				    GOT_STATUS_CANNOT_UPDATE, err);
1087 			else if (err->code == GOT_ERR_HUNK_FAILED)
1088 				err = report_progress(&pa, p.old, p.new,
1089 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1090 		}
1091 		if (overlapcnt != 0)
1092 			failed = 1;
1093 
1094 		free(oldpath);
1095 		free(newpath);
1096 		patch_free(&p);
1097 
1098 		if (err)
1099 			break;
1100 	}
1101 
1102 done:
1103 	if (fileindex != NULL)
1104 		complete_err = got_worktree_patch_complete(fileindex,
1105 		    fileindex_path);
1106 	if (complete_err && err == NULL)
1107 		err = complete_err;
1108 	free(fileindex_path);
1109 	if (tree)
1110 		got_object_tree_close(tree);
1111 	if (commit)
1112 		got_object_commit_close(commit);
1113 	if (fd != -1 && close(fd) == -1 && err == NULL)
1114 		err = got_error_from_errno("close");
1115 	if (ibuf != NULL)
1116 		imsg_clear(ibuf);
1117 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1118 		err = got_error_from_errno("close");
1119 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1120 		err = got_error_from_errno("close");
1121 	if (err == NULL && failed)
1122 		err = got_error(GOT_ERR_PATCH_FAILED);
1123 	return err;
1124 }