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