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 	int	 xbit;
76 	char	*old;
77 	char	*new;
78 	char	 cid[41];
79 	char	 blob[41];
80 	struct got_patch_hunk_head head;
81 };
82 
83 struct patch_args {
84 	got_patch_progress_cb progress_cb;
85 	void	*progress_arg;
86 	struct got_patch_hunk_head *head;
87 };
88 
89 static mode_t
90 apply_umask(mode_t mode)
91 {
92 	mode_t um;
93 
94 	um = umask(000);
95 	umask(um);
96 	return mode & ~um;
97 }
98 
99 static const struct got_error *
100 send_patch(struct imsgbuf *ibuf, int fd)
101 {
102 	const struct got_error *err = NULL;
103 
104 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
105 	    NULL, 0) == -1) {
106 		err = got_error_from_errno(
107 		    "imsg_compose GOT_IMSG_PATCH_FILE");
108 		close(fd);
109 		return err;
110 	}
111 
112 	return got_privsep_flush_imsg(ibuf);
113 }
114 
115 static void
116 patch_free(struct got_patch *p)
117 {
118 	struct got_patch_hunk *h;
119 	size_t i;
120 
121 	while (!STAILQ_EMPTY(&p->head)) {
122 		h = STAILQ_FIRST(&p->head);
123 		STAILQ_REMOVE_HEAD(&p->head, entries);
124 
125 		for (i = 0; i < h->len; ++i)
126 			free(h->lines[i]);
127 		free(h->lines);
128 		free(h);
129 	}
130 
131 	free(p->new);
132 	free(p->old);
133 
134 	memset(p, 0, sizeof(*p));
135 	STAILQ_INIT(&p->head);
136 }
137 
138 static const struct got_error *
139 pushline(struct got_patch_hunk *h, const char *line)
140 {
141 	void 	*t;
142 	size_t	 newcap;
143 
144 	if (h->len == h->cap) {
145 		if ((newcap = h->cap * 1.5) == 0)
146 			newcap = 16;
147 		t = recallocarray(h->lines, h->cap, newcap,
148 		    sizeof(h->lines[0]));
149 		if (t == NULL)
150 			return got_error_from_errno("recallocarray");
151 		h->lines = t;
152 		h->cap = newcap;
153 	}
154 
155 	if ((t = strdup(line)) == NULL)
156 		return got_error_from_errno("strdup");
157 
158 	h->lines[h->len++] = t;
159 	return NULL;
160 }
161 
162 static const struct got_error *
163 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
164 {
165 	const struct got_error *err = NULL;
166 	struct imsg imsg;
167 	struct got_imsg_patch_hunk hdr;
168 	struct got_imsg_patch patch;
169 	struct got_patch_hunk *h = NULL;
170 	size_t datalen;
171 	int lastmode = -1;
172 
173 	memset(p, 0, sizeof(*p));
174 	STAILQ_INIT(&p->head);
175 
176 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
177 	if (err)
178 		return err;
179 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
180 		*done = 1;
181 		goto done;
182 	}
183 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
184 		err = got_error(GOT_ERR_PRIVSEP_MSG);
185 		goto done;
186 	}
187 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
188 	if (datalen != sizeof(patch)) {
189 		err = got_error(GOT_ERR_PRIVSEP_LEN);
190 		goto done;
191 	}
192 	memcpy(&patch, imsg.data, sizeof(patch));
193 
194 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
195 	    patch.new[sizeof(patch.new)-1] != '\0' ||
196 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
197 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
198 		err = got_error(GOT_ERR_PRIVSEP_LEN);
199 		goto done;
200 	}
201 
202 	if (*patch.cid != '\0')
203 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
204 
205 	if (*patch.blob != '\0')
206 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
207 
208 	p->xbit = patch.xbit;
209 
210 	/* automatically set strip=1 for git-style diffs */
211 	if (strip == -1 && patch.git &&
212 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
213 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
214 		strip = 1;
215 
216 	/* prefer the new name if not /dev/null for not git-style diffs */
217 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
218 		err = got_path_strip(&p->old, patch.new, strip);
219 		if (err)
220 			goto done;
221 	} else if (*patch.old != '\0') {
222 		err = got_path_strip(&p->old, patch.old, strip);
223 		if (err)
224 			goto done;
225 	}
226 
227 	if (*patch.new != '\0') {
228 		err = got_path_strip(&p->new, patch.new, strip);
229 		if (err)
230 			goto done;
231 	}
232 
233 	if (p->old == NULL && p->new == NULL) {
234 		err = got_error(GOT_ERR_PATCH_MALFORMED);
235 		goto done;
236 	}
237 
238 	imsg_free(&imsg);
239 
240 	for (;;) {
241 		char *t;
242 
243 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
244 		if (err) {
245 			patch_free(p);
246 			return err;
247 		}
248 
249 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
250 		switch (imsg.hdr.type) {
251 		case GOT_IMSG_PATCH_DONE:
252 			if (h != NULL && h->len == 0)
253 				err = got_error(GOT_ERR_PATCH_MALFORMED);
254 			goto done;
255 		case GOT_IMSG_PATCH_HUNK:
256 			if (h != NULL &&
257 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
258 				err = got_error(GOT_ERR_PATCH_MALFORMED);
259 				goto done;
260 			}
261 			lastmode = -1;
262 			if (datalen != sizeof(hdr)) {
263 				err = got_error(GOT_ERR_PRIVSEP_LEN);
264 				goto done;
265 			}
266 			memcpy(&hdr, imsg.data, sizeof(hdr));
267 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
268 				err = got_error(GOT_ERR_PRIVSEP_LEN);
269 				goto done;
270 			}
271 			if ((h = calloc(1, sizeof(*h))) == NULL) {
272 				err = got_error_from_errno("calloc");
273 				goto done;
274 			}
275 			h->old_from = hdr.oldfrom;
276 			h->old_lines = hdr.oldlines;
277 			h->new_from = hdr.newfrom;
278 			h->new_lines = hdr.newlines;
279 			STAILQ_INSERT_TAIL(&p->head, h, entries);
280 			break;
281 		case GOT_IMSG_PATCH_LINE:
282 			if (h == NULL) {
283 				err = got_error(GOT_ERR_PRIVSEP_MSG);
284 				goto done;
285 			}
286 			t = imsg.data;
287 			/* at least one char */
288 			if (datalen < 2 || t[datalen-1] != '\0') {
289 				err = got_error(GOT_ERR_PRIVSEP_MSG);
290 				goto done;
291 			}
292 			if (*t != ' ' && *t != '-' && *t != '+' &&
293 			    *t != '\\') {
294 				err = got_error(GOT_ERR_PRIVSEP_MSG);
295 				goto done;
296 			}
297 
298 			if (*t != '\\')
299 				err = pushline(h, t);
300 			else if (lastmode == '-')
301 				h->old_nonl = 1;
302 			else if (lastmode == '+')
303 				h->new_nonl = 1;
304 			else
305 				err = got_error(GOT_ERR_PATCH_MALFORMED);
306 
307 			if (err)
308 				goto done;
309 
310 			lastmode = *t;
311 			break;
312 		default:
313 			err = got_error(GOT_ERR_PRIVSEP_MSG);
314 			goto done;
315 		}
316 
317 		imsg_free(&imsg);
318 	}
319 
320 done:
321 	if (err)
322 		patch_free(p);
323 
324 	imsg_free(&imsg);
325 	return err;
326 }
327 
328 static void
329 reverse_patch(struct got_patch *p)
330 {
331 	struct got_patch_hunk *h;
332 	size_t i;
333 	int tmp;
334 
335 	STAILQ_FOREACH(h, &p->head, entries) {
336 		tmp = h->old_from;
337 		h->old_from = h->new_from;
338 		h->new_from = tmp;
339 
340 		tmp = h->old_lines;
341 		h->old_lines = h->new_lines;
342 		h->new_lines = tmp;
343 
344 		tmp = h->old_nonl;
345 		h->old_nonl = h->new_nonl;
346 		h->new_nonl = tmp;
347 
348 		for (i = 0; i < h->len; ++i) {
349 			if (*h->lines[i] == '+')
350 				*h->lines[i] = '-';
351 			else if (*h->lines[i] == '-')
352 				*h->lines[i] = '+';
353 		}
354 	}
355 }
356 
357 /*
358  * Copy data from orig starting at copypos until pos into tmp.
359  * If pos is -1, copy until EOF.
360  */
361 static const struct got_error *
362 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
363 {
364 	char buf[BUFSIZ];
365 	size_t len, r, w;
366 
367 	if (fseeko(orig, copypos, SEEK_SET) == -1)
368 		return got_error_from_errno("fseeko");
369 
370 	while (pos == -1 || copypos < pos) {
371 		len = sizeof(buf);
372 		if (pos > 0)
373 			len = MIN(len, (size_t)pos - copypos);
374 		r = fread(buf, 1, len, orig);
375 		if (r != len && ferror(orig))
376 			return got_error_from_errno("fread");
377 		w = fwrite(buf, 1, r, tmp);
378 		if (w != r)
379 			return got_error_from_errno("fwrite");
380 		copypos += len;
381 		if (r != len && feof(orig)) {
382 			if (pos == -1)
383 				return NULL;
384 			return got_error(GOT_ERR_HUNK_FAILED);
385 		}
386 	}
387 	return NULL;
388 }
389 
390 static int linecmp(const char *, const char *, int *);
391 
392 static const struct got_error *
393 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
394 {
395 	const struct got_error *err = NULL;
396 	char *line = NULL;
397 	char mode = *h->lines[0];
398 	size_t linesize = 0;
399 	ssize_t linelen;
400 	off_t match = -1;
401 	int mangled = 0, match_lineno = -1;
402 
403 	for (;;) {
404 		linelen = getline(&line, &linesize, orig);
405 		if (linelen == -1) {
406 			if (ferror(orig))
407 				err = got_error_from_errno("getline");
408 			else if (match == -1)
409 				err = got_error(GOT_ERR_HUNK_FAILED);
410 			break;
411 		}
412 		if (line[linelen - 1] == '\n')
413 			line[linelen - 1] = '\0';
414 		(*lineno)++;
415 
416 		if ((mode == ' ' && !linecmp(h->lines[0] + 1, line, &mangled)) ||
417 		    (mode == '-' && !linecmp(h->lines[0] + 1, line, &mangled)) ||
418 		    (mode == '+' && *lineno == h->old_from)) {
419 			match = ftello(orig);
420 			if (match == -1) {
421 				err = got_error_from_errno("ftello");
422 				break;
423 			}
424 			match -= linelen;
425 			match_lineno = (*lineno)-1;
426 		}
427 
428 		if (*lineno >= h->old_from && match != -1) {
429 			if (mangled)
430 				h->ws_mangled = 1;
431 			break;
432 		}
433 	}
434 
435 	if (err == NULL) {
436 		*pos = match;
437 		*lineno = match_lineno;
438 		if (fseeko(orig, match, SEEK_SET) == -1)
439 			err = got_error_from_errno("fseeko");
440 	}
441 
442 	free(line);
443 	return err;
444 }
445 
446 static int
447 linecmp(const char *a, const char *b, int *mangled)
448 {
449 	int c;
450 
451 	*mangled = 0;
452 	c = strcmp(a, b);
453 	if (c == 0)
454 		return c;
455 
456 	*mangled = 1;
457 	for (;;) {
458 		while (*a == '\t' || *a == ' ' || *a == '\f')
459 			a++;
460 		while (*b == '\t' || *b == ' ' || *b == '\f')
461 			b++;
462 		if (*a == '\0' || *a != *b)
463 			break;
464 		a++, b++;
465 	}
466 
467 	return *a - *b;
468 }
469 
470 static const struct got_error *
471 test_hunk(FILE *orig, struct got_patch_hunk *h)
472 {
473 	const struct got_error *err = NULL;
474 	char *line = NULL;
475 	size_t linesize = 0, i = 0;
476 	ssize_t linelen;
477 	int mangled;
478 
479 	for (i = 0; i < h->len; ++i) {
480 		switch (*h->lines[i]) {
481 		case '+':
482 			continue;
483 		case ' ':
484 		case '-':
485 			linelen = getline(&line, &linesize, orig);
486 			if (linelen == -1) {
487 				if (ferror(orig))
488 					err = got_error_from_errno("getline");
489 				else
490 					err = got_error(
491 					    GOT_ERR_HUNK_FAILED);
492 				goto done;
493 			}
494 			if (line[linelen - 1] == '\n')
495 				line[linelen - 1] = '\0';
496 			if (linecmp(h->lines[i] + 1, line, &mangled)) {
497 				err = got_error(GOT_ERR_HUNK_FAILED);
498 				goto done;
499 			}
500 			if (mangled)
501 				h->ws_mangled = 1;
502 			break;
503 		}
504 	}
505 
506 done:
507 	free(line);
508 	return err;
509 }
510 
511 static const struct got_error *
512 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
513     off_t from)
514 {
515 	const struct got_error *err = NULL;
516 	const char *t;
517 	size_t linesize = 0, i, new = 0;
518 	char *line = NULL;
519 	char mode;
520 	ssize_t linelen;
521 
522 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
523 		return got_error_from_errno("fseeko");
524 
525 	for (i = 0; i < h->len; ++i) {
526 		switch (mode = *h->lines[i]) {
527 		case '-':
528 		case ' ':
529 			(*lineno)++;
530 			if (orig != NULL) {
531 				linelen = getline(&line, &linesize, orig);
532 				if (linelen == -1) {
533 					err = got_error_from_errno("getline");
534 					goto done;
535 				}
536 				if (line[linelen - 1] == '\n')
537 					line[linelen - 1] = '\0';
538 				t = line;
539 			} else
540 				t = h->lines[i] + 1;
541 			if (mode == '-')
542 				continue;
543 			if (fprintf(tmp, "%s\n", t) < 0) {
544 				err = got_error_from_errno("fprintf");
545 				goto done;
546 			}
547 			break;
548 		case '+':
549 			new++;
550 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0) {
551 				err = got_error_from_errno("fprintf");
552 				goto done;
553 			}
554 			if (new != h->new_lines || !h->new_nonl) {
555 				if (fprintf(tmp, "\n") < 0) {
556 					err = got_error_from_errno("fprintf");
557 					goto done;
558 				}
559 			}
560 			break;
561 		}
562 	}
563 
564 done:
565 	free(line);
566 	return err;
567 }
568 
569 static const struct got_error *
570 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
571 {
572 	const struct got_error *err = NULL;
573 	struct got_patch_hunk *h;
574 	struct stat sb;
575 	int lineno = 0;
576 	off_t copypos, pos;
577 	char *line = NULL;
578 	size_t linesize = 0;
579 	ssize_t linelen;
580 
581 	if (p->old == NULL) {				/* create */
582 		h = STAILQ_FIRST(&p->head);
583 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
584 			return got_error(GOT_ERR_PATCH_MALFORMED);
585 		return apply_hunk(orig, tmp, h, &lineno, 0);
586 	}
587 
588 	/* When deleting binary files there are no hunks to apply. */
589 	if (p->new == NULL && STAILQ_EMPTY(&p->head))
590 		return NULL;
591 
592 	if (fstat(fileno(orig), &sb) == -1)
593 		return got_error_from_errno("fstat");
594 
595 	copypos = 0;
596 	STAILQ_FOREACH(h, &p->head, entries) {
597 	tryagain:
598 		err = locate_hunk(orig, h, &pos, &lineno);
599 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
600 			h->err = err;
601 		if (err != NULL)
602 			return err;
603 		err = copy(tmp, orig, copypos, pos);
604 		if (err != NULL)
605 			return err;
606 		copypos = pos;
607 
608 		err = test_hunk(orig, h);
609 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
610 			/*
611 			 * try to apply the hunk again starting the search
612 			 * after the previous partial match.
613 			 */
614 			if (fseeko(orig, pos, SEEK_SET) == -1)
615 				return got_error_from_errno("fseeko");
616 			linelen = getline(&line, &linesize, orig);
617 			if (linelen == -1)
618 				return got_error_from_errno("getline");
619 			lineno++;
620 			goto tryagain;
621 		}
622 		if (err != NULL)
623 			return err;
624 
625 		if (lineno + 1 != h->old_from)
626 			h->offset = lineno + 1 - h->old_from;
627 
628 		err = apply_hunk(orig, tmp, h, &lineno, pos);
629 		if (err != NULL)
630 			return err;
631 
632 		copypos = ftello(orig);
633 		if (copypos == -1)
634 			return got_error_from_errno("ftello");
635 	}
636 
637 	if (p->new == NULL && sb.st_size != copypos) {
638 		h = STAILQ_FIRST(&p->head);
639 		h->err = got_error(GOT_ERR_HUNK_FAILED);
640 		err = h->err;
641 	} else if (!feof(orig))
642 		err = copy(tmp, orig, copypos, -1);
643 
644 	return err;
645 }
646 
647 static const struct got_error *
648 report_progress(struct patch_args *pa, const char *old, const char *new,
649     unsigned char status, const struct got_error *orig_error)
650 {
651 	const struct got_error *err;
652 	struct got_patch_hunk *h;
653 
654 	err = pa->progress_cb(pa->progress_arg, old, new, status,
655 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
656 	if (err)
657 		return err;
658 
659 	STAILQ_FOREACH(h, pa->head, entries) {
660 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
661 			continue;
662 
663 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
664 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
665 		    h->offset, h->ws_mangled, h->err);
666 		if (err)
667 			return err;
668 	}
669 
670 	return NULL;
671 }
672 
673 static const struct got_error *
674 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
675     const char *path)
676 {
677 	return report_progress(arg, path, NULL, status, NULL);
678 }
679 
680 static const struct got_error *
681 patch_add(void *arg, unsigned char status, const char *path)
682 {
683 	return report_progress(arg, NULL, path, status, NULL);
684 }
685 
686 static const struct got_error *
687 open_blob(char **path, FILE **fp, const char *blobid,
688     struct got_repository *repo)
689 {
690 	const struct got_error *err = NULL;
691 	struct got_blob_object *blob = NULL;
692 	struct got_object_id id, *idptr, *matched_id = NULL;
693 	int fd = -1;
694 
695 	*fp = NULL;
696 	*path = NULL;
697 
698 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
699 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
700 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
701 		    repo);
702 		if (err)
703 			return err;
704 		idptr = matched_id;
705 	} else {
706 		if (!got_parse_sha1_digest(id.sha1, blobid))
707 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
708 		idptr = &id;
709 	}
710 
711 	fd = got_opentempfd();
712 	if (fd == -1) {
713 		err = got_error_from_errno("got_opentempfd");
714 		goto done;
715 	}
716 
717 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
718 	if (err)
719 		goto done;
720 
721 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob",
722 	    "");
723 	if (err)
724 		goto done;
725 
726 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
727 	if (err)
728 		goto done;
729 
730 done:
731 	if (fd != -1 && close(fd) == -1 && err == NULL)
732 		err = got_error_from_errno("close");
733 	if (blob)
734 		got_object_blob_close(blob);
735 	if (matched_id != NULL)
736 		free(matched_id);
737 	if (err) {
738 		if (*fp != NULL)
739 			fclose(*fp);
740 		if (*path != NULL)
741 			unlink(*path);
742 		free(*path);
743 		*fp = NULL;
744 		*path = NULL;
745 	}
746 	return err;
747 }
748 
749 static const struct got_error *
750 prepare_merge(int *do_merge, char **apath, FILE **afile,
751     struct got_worktree *worktree, struct got_repository *repo,
752     struct got_patch *p, struct got_object_id *commit_id,
753     struct got_tree_object *tree, const char *path)
754 {
755 	const struct got_error *err = NULL;
756 
757 	*do_merge = 0;
758 	*apath = NULL;
759 	*afile = NULL;
760 
761 	/* don't run the diff3 merge on creations/deletions */
762 	if (p->old == NULL || p->new == NULL)
763 		return NULL;
764 
765 	if (commit_id) {
766 		struct got_object_id *id;
767 
768 		err = got_object_tree_find_path(&id, NULL, repo, tree, path);
769 		if (err)
770 			return err;
771 		got_sha1_digest_to_str(id->sha1, p->blob, sizeof(p->blob));
772 		got_sha1_digest_to_str(commit_id->sha1, p->cid, sizeof(p->cid));
773 		free(id);
774 		err = open_blob(apath, afile, p->blob, repo);
775 		*do_merge = err == NULL;
776 	} else if (*p->blob != '\0') {
777 		err = open_blob(apath, afile, p->blob, repo);
778 		/*
779 		 * ignore failures to open this blob, we might have
780 		 * parsed gibberish.
781 		 */
782 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
783 		    err->code != GOT_ERR_NO_OBJ)
784 			return err;
785 		*do_merge = err == NULL;
786 		err = NULL;
787 	}
788 
789 	return err;
790 }
791 
792 static const struct got_error *
793 apply_patch(int *overlapcnt, struct got_worktree *worktree,
794     struct got_repository *repo, struct got_fileindex *fileindex,
795     const char *old, const char *new, struct got_patch *p, int nop,
796     int reverse, struct got_object_id *commit_id,
797     struct got_tree_object *tree, struct patch_args *pa,
798     got_cancel_cb cancel_cb, void *cancel_arg)
799 {
800 	const struct got_error *err = NULL;
801 	struct stat sb;
802 	int do_merge = 0, file_renamed = 0;
803 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
804 	char *oldpath = NULL, *newpath = NULL;
805 	char *tmppath = NULL, *template = NULL;
806 	char *apath = NULL, *mergepath = NULL;
807 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
808 	int outfd;
809 	mode_t mode = GOT_DEFAULT_FILE_MODE;
810 
811 	*overlapcnt = 0;
812 
813 	err = prepare_merge(&do_merge, &apath, &afile, worktree, repo, p,
814 	    commit_id, tree, old);
815 	if (err)
816 		return err;
817 
818 	if (reverse && !do_merge)
819 		reverse_patch(p);
820 
821 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
822 	    old) == -1) {
823 		err = got_error_from_errno("asprintf");
824 		goto done;
825 	}
826 
827 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
828 	    new) == -1) {
829 		err = got_error_from_errno("asprintf");
830 		goto done;
831 	}
832 
833 	file_renamed = strcmp(oldpath, newpath);
834 
835 	if (asprintf(&template, "%s/got-patch",
836 	    got_worktree_get_root_path(worktree)) == -1) {
837 		err = got_error_from_errno(template);
838 		goto done;
839 	}
840 
841 	if (p->old != NULL) {
842 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
843 			err = got_error_from_errno2("open", oldpath);
844 			goto done;
845 		}
846 		if (fstat(fileno(oldfile), &sb) == -1) {
847 			err = got_error_from_errno2("fstat", oldpath);
848 			goto done;
849 		}
850 		mode = sb.st_mode;
851 	} else if (p->xbit)
852 		mode |= (S_IXUSR | S_IXGRP | S_IXOTH);
853 
854 	err = got_opentemp_named(&tmppath, &tmpfile, template, "");
855 	if (err)
856 		goto done;
857 	outfd = fileno(tmpfile);
858 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
859 	if (err)
860 		goto done;
861 
862 	if (do_merge) {
863 		const char *type, *id;
864 
865 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
866 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
867 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
868 			err = got_error_from_errno("fseeko");
869 			goto done;
870 		}
871 
872 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
873 			err = got_error_from_errno("asprintf");
874 			oldlabel = NULL;
875 			goto done;
876 		}
877 
878 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
879 			err = got_error_from_errno("asprintf");
880 			newlabel = NULL;
881 			goto done;
882 		}
883 
884 		if (*p->cid != '\0') {
885 			type = "commit";
886 			id = p->cid;
887 		} else {
888 			type = "blob";
889 			id = p->blob;
890 		}
891 
892 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
893 			err = got_error_from_errno("asprintf");
894 			anclabel = NULL;
895 			goto done;
896 		}
897 
898 		if (reverse) {
899 			char *s;
900 			FILE *t;
901 
902 			s = anclabel;
903 			anclabel = newlabel;
904 			newlabel = s;
905 
906 			t = afile;
907 			afile = tmpfile;
908 			tmpfile = t;
909 		}
910 
911 		err = got_opentemp_named(&mergepath, &mergefile, template, "");
912 		if (err)
913 			goto done;
914 		outfd = fileno(mergefile);
915 
916 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
917 		    oldfile, oldlabel, anclabel, newlabel,
918 		    GOT_DIFF_ALGORITHM_PATIENCE);
919 		if (err)
920 			goto done;
921 	}
922 
923 	if (nop)
924 		goto done;
925 
926 	if (p->old != NULL && p->new == NULL) {
927 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
928 		    fileindex, patch_delete, pa);
929 		goto done;
930 	}
931 
932 	if (fchmod(outfd, apply_umask(mode)) == -1) {
933 		err = got_error_from_errno2("chmod", tmppath);
934 		goto done;
935 	}
936 
937 	if (mergepath) {
938 		err = got_path_move_file(mergepath, newpath);
939 		if (err)
940 			goto done;
941 		free(mergepath);
942 		mergepath = NULL;
943 	} else {
944 		err = got_path_move_file(tmppath, newpath);
945 		if (err)
946 			goto done;
947 		free(tmppath);
948 		tmppath = NULL;
949 	}
950 
951 	if (file_renamed) {
952 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
953 		    fileindex, patch_delete, pa);
954 		if (err == NULL)
955 			err = got_worktree_patch_schedule_add(new, repo,
956 			    worktree, fileindex, patch_add,
957 			    pa);
958 		if (err)
959 			unlink(newpath);
960 	} else if (p->old == NULL) {
961 		err = got_worktree_patch_schedule_add(new, repo, worktree,
962 		    fileindex, patch_add, pa);
963 		if (err)
964 			unlink(newpath);
965 	} else if (*overlapcnt != 0)
966 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
967 	else if (do_merge)
968 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
969 	else
970 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
971 
972 done:
973 	free(template);
974 
975 	if (tmppath != NULL && unlink(tmppath) == -1 && err == NULL)
976 		err = got_error_from_errno("unlink");
977 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
978 		err = got_error_from_errno("fclose");
979 	free(tmppath);
980 
981 	free(oldpath);
982 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
983 		err = got_error_from_errno("fclose");
984 
985 	if (apath != NULL && unlink(apath) == -1 && err == NULL)
986 		err = got_error_from_errno("unlink");
987 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
988 		err = got_error_from_errno("fclose");
989 	free(apath);
990 
991 	if (mergepath != NULL && unlink(mergepath) == -1 && err == NULL)
992 		err = got_error_from_errno("unlink");
993 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
994 		err = got_error_from_errno("fclose");
995 	free(mergepath);
996 
997 	free(newpath);
998 	free(oldlabel);
999 	free(newlabel);
1000 	free(anclabel);
1001 	return err;
1002 }
1003 
1004 const struct got_error *
1005 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
1006     int nop, int strip, int reverse, struct got_object_id *commit_id,
1007     got_patch_progress_cb progress_cb, void *progress_arg,
1008     got_cancel_cb cancel_cb, void *cancel_arg)
1009 {
1010 	const struct got_error *err = NULL, *complete_err = NULL;
1011 	struct got_fileindex *fileindex = NULL;
1012 	struct got_commit_object *commit = NULL;
1013 	struct got_tree_object *tree = NULL;
1014 	char *fileindex_path = NULL;
1015 	char *oldpath, *newpath;
1016 	struct imsgbuf *ibuf;
1017 	int imsg_fds[2] = {-1, -1};
1018 	int overlapcnt, done = 0, failed = 0;
1019 	pid_t pid;
1020 
1021 	ibuf = calloc(1, sizeof(*ibuf));
1022 	if (ibuf == NULL) {
1023 		err = got_error_from_errno("calloc");
1024 		goto done;
1025 	}
1026 
1027 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1028 		err = got_error_from_errno("socketpair");
1029 		goto done;
1030 	}
1031 
1032 	pid = fork();
1033 	if (pid == -1) {
1034 		err = got_error_from_errno("fork");
1035 		goto done;
1036 	} else if (pid == 0) {
1037 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
1038 		    NULL);
1039 		/* not reached */
1040 	}
1041 
1042 	if (close(imsg_fds[1]) == -1) {
1043 		err = got_error_from_errno("close");
1044 		goto done;
1045 	}
1046 	imsg_fds[1] = -1;
1047 	imsg_init(ibuf, imsg_fds[0]);
1048 
1049 	err = send_patch(ibuf, fd);
1050 	fd = -1;
1051 	if (err)
1052 		goto done;
1053 
1054 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
1055 	    worktree);
1056 	if (err)
1057 		goto done;
1058 
1059 	if (commit_id) {
1060 		err = got_object_open_as_commit(&commit, repo, commit_id);
1061 		if (err)
1062 			goto done;
1063 
1064 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1065 		if (err)
1066 			goto done;
1067 	}
1068 
1069 	while (!done && err == NULL) {
1070 		struct got_patch p;
1071 		struct patch_args pa;
1072 
1073 		pa.progress_cb = progress_cb;
1074 		pa.progress_arg = progress_arg;
1075 		pa.head = &p.head;
1076 
1077 		err = recv_patch(ibuf, &done, &p, strip);
1078 		if (err || done)
1079 			break;
1080 
1081 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1082 		    &newpath, worktree, repo, fileindex);
1083 		if (err == NULL)
1084 			err = apply_patch(&overlapcnt, worktree, repo,
1085 			    fileindex, oldpath, newpath, &p, nop, reverse,
1086 			    commit_id, tree, &pa, cancel_cb, cancel_arg);
1087 		if (err != NULL) {
1088 			failed = 1;
1089 			/* recoverable errors */
1090 			if (err->code == GOT_ERR_FILE_STATUS ||
1091 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1092 				err = report_progress(&pa, p.old, p.new,
1093 				    GOT_STATUS_CANNOT_UPDATE, err);
1094 			else if (err->code == GOT_ERR_HUNK_FAILED)
1095 				err = report_progress(&pa, p.old, p.new,
1096 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1097 		}
1098 		if (overlapcnt != 0)
1099 			failed = 1;
1100 
1101 		free(oldpath);
1102 		free(newpath);
1103 		patch_free(&p);
1104 
1105 		if (err)
1106 			break;
1107 	}
1108 
1109 done:
1110 	if (fileindex != NULL)
1111 		complete_err = got_worktree_patch_complete(fileindex,
1112 		    fileindex_path);
1113 	if (complete_err && err == NULL)
1114 		err = complete_err;
1115 	free(fileindex_path);
1116 	if (tree)
1117 		got_object_tree_close(tree);
1118 	if (commit)
1119 		got_object_commit_close(commit);
1120 	if (fd != -1 && close(fd) == -1 && err == NULL)
1121 		err = got_error_from_errno("close");
1122 	if (ibuf != NULL)
1123 		imsg_clear(ibuf);
1124 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1125 		err = got_error_from_errno("close");
1126 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1127 		err = got_error_from_errno("close");
1128 	if (err == NULL && failed)
1129 		err = got_error(GOT_ERR_PATCH_FAILED);
1130 	return err;
1131 }