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 #include "got_compat.h"
23 
24 #include <sys/types.h>
25 #include <sys/queue.h>
26 #include <sys/socket.h>
27 #include <sys/stat.h>
28 #include <sys/uio.h>
29 
30 #include <ctype.h>
31 #include <errno.h>
32 #include <limits.h>
33 #include <stdint.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <unistd.h>
38 
39 #include "got_error.h"
40 #include "got_object.h"
41 #include "got_path.h"
42 #include "got_reference.h"
43 #include "got_cancel.h"
44 #include "got_worktree.h"
45 #include "got_repository.h"
46 #include "got_opentemp.h"
47 #include "got_patch.h"
48 #include "got_diff.h"
49 
50 #include "got_lib_delta.h"
51 #include "got_lib_diff.h"
52 #include "got_lib_object.h"
53 #include "got_lib_privsep.h"
54 #include "got_lib_hash.h"
55 
56 #ifndef MIN
57 #define MIN(a, b) ((a) < (b) ? (a) : (b))
58 #endif
59 
60 struct got_patch_line {
61 	char	 mode;
62 	char	*line;
63 	size_t	 len;
64 };
65 
66 struct got_patch_hunk {
67 	STAILQ_ENTRY(got_patch_hunk) entries;
68 	const struct got_error *err;
69 	int	ws_mangled;
70 	int	offset;
71 	int	old_nonl;
72 	int	new_nonl;
73 	int	old_from;
74 	int	old_lines;
75 	int	new_from;
76 	int	new_lines;
77 	size_t	len;
78 	size_t	cap;
79 	struct got_patch_line *lines;
80 };
81 
82 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
83 struct got_patch {
84 	int	 xbit;
85 	char	*old;
86 	char	*new;
87 	char	 cid[41];
88 	char	 blob[41];
89 	struct got_patch_hunk_head head;
90 };
91 
92 struct patch_args {
93 	got_patch_progress_cb progress_cb;
94 	void	*progress_arg;
95 	struct got_patch_hunk_head *head;
96 };
97 
98 static mode_t
99 apply_umask(mode_t mode)
100 {
101 	mode_t um;
102 
103 	um = umask(000);
104 	umask(um);
105 	return mode & ~um;
106 }
107 
108 static const struct got_error *
109 send_patch(struct imsgbuf *ibuf, int fd)
110 {
111 	const struct got_error *err = NULL;
112 
113 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
114 	    NULL, 0) == -1) {
115 		err = got_error_from_errno(
116 		    "imsg_compose GOT_IMSG_PATCH_FILE");
117 		close(fd);
118 		return err;
119 	}
120 
121 	return got_privsep_flush_imsg(ibuf);
122 }
123 
124 static void
125 patch_free(struct got_patch *p)
126 {
127 	struct got_patch_hunk *h;
128 	size_t i;
129 
130 	while (!STAILQ_EMPTY(&p->head)) {
131 		h = STAILQ_FIRST(&p->head);
132 		STAILQ_REMOVE_HEAD(&p->head, entries);
133 
134 		for (i = 0; i < h->len; ++i)
135 			free(h->lines[i].line);
136 		free(h->lines);
137 		free(h);
138 	}
139 
140 	free(p->new);
141 	free(p->old);
142 
143 	memset(p, 0, sizeof(*p));
144 	STAILQ_INIT(&p->head);
145 }
146 
147 static const struct got_error *
148 pushline(struct got_patch_hunk *h, const char *line, size_t len)
149 {
150 	void 	*t;
151 	size_t	 newcap;
152 
153 	if (h->len == h->cap) {
154 		if ((newcap = h->cap * 1.5) == 0)
155 			newcap = 16;
156 		t = recallocarray(h->lines, h->cap, newcap,
157 		    sizeof(h->lines[0]));
158 		if (t == NULL)
159 			return got_error_from_errno("recallocarray");
160 		h->lines = t;
161 		h->cap = newcap;
162 	}
163 
164 	if ((t = malloc(len - 1)) == NULL)
165 		return got_error_from_errno("malloc");
166 	memcpy(t, line + 1, len - 1);	/* skip the line type */
167 
168 	h->lines[h->len].mode = *line;
169 	h->lines[h->len].line = t;
170 	h->lines[h->len].len = len - 2;	/* line type and trailing NUL */
171 	h->len++;
172 	return NULL;
173 }
174 
175 static const struct got_error *
176 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
177 {
178 	const struct got_error *err = NULL;
179 	struct imsg imsg;
180 	struct got_imsg_patch_hunk hdr;
181 	struct got_imsg_patch patch;
182 	struct got_patch_hunk *h = NULL;
183 	size_t datalen;
184 	int lastmode = -1;
185 
186 	memset(p, 0, sizeof(*p));
187 	STAILQ_INIT(&p->head);
188 
189 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
190 	if (err)
191 		return err;
192 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
193 		*done = 1;
194 		goto done;
195 	}
196 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
197 		err = got_error(GOT_ERR_PRIVSEP_MSG);
198 		goto done;
199 	}
200 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
201 	if (datalen != sizeof(patch)) {
202 		err = got_error(GOT_ERR_PRIVSEP_LEN);
203 		goto done;
204 	}
205 	memcpy(&patch, imsg.data, sizeof(patch));
206 
207 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
208 	    patch.new[sizeof(patch.new)-1] != '\0' ||
209 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
210 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
211 		err = got_error(GOT_ERR_PRIVSEP_LEN);
212 		goto done;
213 	}
214 
215 	if (*patch.cid != '\0')
216 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
217 
218 	if (*patch.blob != '\0')
219 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
220 
221 	p->xbit = patch.xbit;
222 
223 	/* automatically set strip=1 for git-style diffs */
224 	if (strip == -1 && patch.git &&
225 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
226 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
227 		strip = 1;
228 
229 	/* prefer the new name if not /dev/null for not git-style diffs */
230 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
231 		err = got_path_strip(&p->old, patch.new, strip);
232 		if (err)
233 			goto done;
234 	} else if (*patch.old != '\0') {
235 		err = got_path_strip(&p->old, patch.old, strip);
236 		if (err)
237 			goto done;
238 	}
239 
240 	if (*patch.new != '\0') {
241 		err = got_path_strip(&p->new, patch.new, strip);
242 		if (err)
243 			goto done;
244 	}
245 
246 	if (p->old == NULL && p->new == NULL) {
247 		err = got_error(GOT_ERR_PATCH_MALFORMED);
248 		goto done;
249 	}
250 
251 	imsg_free(&imsg);
252 
253 	for (;;) {
254 		char *t;
255 
256 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
257 		if (err) {
258 			patch_free(p);
259 			return err;
260 		}
261 
262 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
263 		switch (imsg.hdr.type) {
264 		case GOT_IMSG_PATCH_DONE:
265 			if (h != NULL && h->len == 0)
266 				err = got_error(GOT_ERR_PATCH_MALFORMED);
267 			goto done;
268 		case GOT_IMSG_PATCH_HUNK:
269 			if (h != NULL &&
270 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
271 				err = got_error(GOT_ERR_PATCH_MALFORMED);
272 				goto done;
273 			}
274 			lastmode = -1;
275 			if (datalen != sizeof(hdr)) {
276 				err = got_error(GOT_ERR_PRIVSEP_LEN);
277 				goto done;
278 			}
279 			memcpy(&hdr, imsg.data, sizeof(hdr));
280 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
281 				err = got_error(GOT_ERR_PRIVSEP_LEN);
282 				goto done;
283 			}
284 			if ((h = calloc(1, sizeof(*h))) == NULL) {
285 				err = got_error_from_errno("calloc");
286 				goto done;
287 			}
288 			h->old_from = hdr.oldfrom;
289 			h->old_lines = hdr.oldlines;
290 			h->new_from = hdr.newfrom;
291 			h->new_lines = hdr.newlines;
292 			STAILQ_INSERT_TAIL(&p->head, h, entries);
293 			break;
294 		case GOT_IMSG_PATCH_LINE:
295 			if (h == NULL) {
296 				err = got_error(GOT_ERR_PRIVSEP_MSG);
297 				goto done;
298 			}
299 			t = imsg.data;
300 			/* at least one char */
301 			if (datalen < 2 || t[datalen-1] != '\0') {
302 				err = got_error(GOT_ERR_PRIVSEP_MSG);
303 				goto done;
304 			}
305 			if (*t != ' ' && *t != '-' && *t != '+' &&
306 			    *t != '\\') {
307 				err = got_error(GOT_ERR_PRIVSEP_MSG);
308 				goto done;
309 			}
310 
311 			if (*t != '\\')
312 				err = pushline(h, t, datalen);
313 			else if (lastmode == '-')
314 				h->old_nonl = 1;
315 			else if (lastmode == '+')
316 				h->new_nonl = 1;
317 			else
318 				err = got_error(GOT_ERR_PATCH_MALFORMED);
319 
320 			if (err)
321 				goto done;
322 
323 			lastmode = *t;
324 			break;
325 		default:
326 			err = got_error(GOT_ERR_PRIVSEP_MSG);
327 			goto done;
328 		}
329 
330 		imsg_free(&imsg);
331 	}
332 
333 done:
334 	if (err)
335 		patch_free(p);
336 
337 	imsg_free(&imsg);
338 	return err;
339 }
340 
341 static void
342 reverse_patch(struct got_patch *p)
343 {
344 	struct got_patch_hunk *h;
345 	size_t i;
346 	int tmp;
347 
348 	STAILQ_FOREACH(h, &p->head, entries) {
349 		tmp = h->old_from;
350 		h->old_from = h->new_from;
351 		h->new_from = tmp;
352 
353 		tmp = h->old_lines;
354 		h->old_lines = h->new_lines;
355 		h->new_lines = tmp;
356 
357 		tmp = h->old_nonl;
358 		h->old_nonl = h->new_nonl;
359 		h->new_nonl = tmp;
360 
361 		for (i = 0; i < h->len; ++i) {
362 			if (h->lines[i].mode == '+')
363 				h->lines[i].mode = '-';
364 			else if (h->lines[i].mode == '-')
365 				h->lines[i].mode = '+';
366 		}
367 	}
368 }
369 
370 /*
371  * Copy data from orig starting at copypos until pos into tmp.
372  * If pos is -1, copy until EOF.
373  */
374 static const struct got_error *
375 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
376 {
377 	char buf[BUFSIZ];
378 	size_t len, r, w;
379 
380 	if (fseeko(orig, copypos, SEEK_SET) == -1)
381 		return got_error_from_errno("fseeko");
382 
383 	while (pos == -1 || copypos < pos) {
384 		len = sizeof(buf);
385 		if (pos > 0)
386 			len = MIN(len, (size_t)pos - copypos);
387 		r = fread(buf, 1, len, orig);
388 		if (r != len && ferror(orig))
389 			return got_error_from_errno("fread");
390 		w = fwrite(buf, 1, r, tmp);
391 		if (w != r)
392 			return got_error_from_errno("fwrite");
393 		copypos += len;
394 		if (r != len && feof(orig)) {
395 			if (pos == -1)
396 				return NULL;
397 			return got_error(GOT_ERR_HUNK_FAILED);
398 		}
399 	}
400 	return NULL;
401 }
402 
403 static int lines_eq(struct got_patch_line *, const char *, size_t, int *);
404 
405 static const struct got_error *
406 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
407 {
408 	const struct got_error *err = NULL;
409 	struct got_patch_line *l = &h->lines[0];
410 	char *line = NULL;
411 	char mode = l->mode;
412 	size_t linesize = 0;
413 	ssize_t linelen;
414 	off_t match = -1;
415 	int mangled = 0, match_lineno = -1;
416 
417 	for (;;) {
418 		linelen = getline(&line, &linesize, orig);
419 		if (linelen == -1) {
420 			if (ferror(orig))
421 				err = got_error_from_errno("getline");
422 			else if (match == -1)
423 				err = got_error(GOT_ERR_HUNK_FAILED);
424 			break;
425 		}
426 		(*lineno)++;
427 
428 		if ((mode == ' ' && lines_eq(l, line, linelen, &mangled)) ||
429 		    (mode == '-' && lines_eq(l, line, linelen, &mangled)) ||
430 		    (mode == '+' && *lineno == h->old_from)) {
431 			match = ftello(orig);
432 			if (match == -1) {
433 				err = got_error_from_errno("ftello");
434 				break;
435 			}
436 			match -= linelen;
437 			match_lineno = (*lineno)-1;
438 		}
439 
440 		if (*lineno >= h->old_from && match != -1) {
441 			if (mangled)
442 				h->ws_mangled = 1;
443 			break;
444 		}
445 	}
446 
447 	if (err == NULL) {
448 		*pos = match;
449 		*lineno = match_lineno;
450 		if (fseeko(orig, match, SEEK_SET) == -1)
451 			err = got_error_from_errno("fseeko");
452 	}
453 
454 	free(line);
455 	return err;
456 }
457 
458 static int
459 lines_eq(struct got_patch_line *l, const char *b, size_t len, int *mangled)
460 {
461 	char *a = l->line;
462 	size_t i, j;
463 
464 	if (len > 00 && b[len - 1] == '\n')
465 		len--;
466 
467 	*mangled = 0;
468 	if (l->len == len && !memcmp(a, b, len))
469 		return 1;
470 
471 	*mangled = 1;
472 
473 	i = j = 0;
474 	for (;;) {
475 		while (i < l->len &&
476 		    (a[i] == '\t' || a[i] == ' ' || a[i] == '\f'))
477 			i++;
478 		while (j < len &&
479 		    (b[j] == '\t' || b[j] == ' ' || b[j] == '\f'))
480 			j++;
481 		if (i == l->len || j == len || a[i] != b[j])
482 			break;
483 		i++, j++;
484 	}
485 
486 	return (i == l->len && j == len);
487 }
488 
489 static const struct got_error *
490 test_hunk(FILE *orig, struct got_patch_hunk *h)
491 {
492 	const struct got_error *err = NULL;
493 	char *line = NULL;
494 	size_t linesize = 0, i = 0;
495 	ssize_t linelen;
496 	int mangled;
497 
498 	for (i = 0; i < h->len; ++i) {
499 		switch (h->lines[i].mode) {
500 		case '+':
501 			continue;
502 		case ' ':
503 		case '-':
504 			linelen = getline(&line, &linesize, orig);
505 			if (linelen == -1) {
506 				if (ferror(orig))
507 					err = got_error_from_errno("getline");
508 				else
509 					err = got_error(
510 					    GOT_ERR_HUNK_FAILED);
511 				goto done;
512 			}
513 			if (!lines_eq(&h->lines[i], line, linelen, &mangled)) {
514 				err = got_error(GOT_ERR_HUNK_FAILED);
515 				goto done;
516 			}
517 			if (mangled)
518 				h->ws_mangled = 1;
519 			break;
520 		}
521 	}
522 
523 done:
524 	free(line);
525 	return err;
526 }
527 
528 static const struct got_error *
529 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
530     off_t from)
531 {
532 	const struct got_error *err = NULL;
533 	const char *t;
534 	size_t linesize = 0, i, new = 0;
535 	char *line = NULL;
536 	char mode;
537 	size_t l;
538 	ssize_t linelen;
539 
540 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
541 		return got_error_from_errno("fseeko");
542 
543 	for (i = 0; i < h->len; ++i) {
544 		switch (mode = h->lines[i].mode) {
545 		case '-':
546 		case ' ':
547 			(*lineno)++;
548 			if (orig != NULL) {
549 				linelen = getline(&line, &linesize, orig);
550 				if (linelen == -1) {
551 					err = got_error_from_errno("getline");
552 					goto done;
553 				}
554 				if (line[linelen - 1] == '\n')
555 					line[linelen - 1] = '\0';
556 				t = line;
557 				l = linelen - 1;
558 			} else {
559 				t = h->lines[i].line;
560 				l = h->lines[i].len;
561 			}
562 			if (mode == '-')
563 				continue;
564 			if (fwrite(t, 1, l, tmp) != l ||
565 			    fputc('\n', tmp) == EOF) {
566 				err = got_error_from_errno("fprintf");
567 				goto done;
568 			}
569 			break;
570 		case '+':
571 			new++;
572 			t = h->lines[i].line;
573 			l = h->lines[i].len;
574 			if (fwrite(t, 1, l, tmp) != l) {
575 				err = got_error_from_errno("fprintf");
576 				goto done;
577 			}
578 			if (new != h->new_lines || !h->new_nonl) {
579 				if (fprintf(tmp, "\n") < 0) {
580 					err = got_error_from_errno("fprintf");
581 					goto done;
582 				}
583 			}
584 			break;
585 		}
586 	}
587 
588 done:
589 	free(line);
590 	return err;
591 }
592 
593 static const struct got_error *
594 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
595 {
596 	const struct got_error *err = NULL;
597 	struct got_patch_hunk *h;
598 	struct stat sb;
599 	int lineno = 0;
600 	off_t copypos, pos;
601 	char *line = NULL;
602 	size_t linesize = 0;
603 	ssize_t linelen;
604 
605 	if (p->old == NULL) {				/* create */
606 		h = STAILQ_FIRST(&p->head);
607 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
608 			return got_error(GOT_ERR_PATCH_MALFORMED);
609 		return apply_hunk(orig, tmp, h, &lineno, 0);
610 	}
611 
612 	/* When deleting binary files there are no hunks to apply. */
613 	if (p->new == NULL && STAILQ_EMPTY(&p->head))
614 		return NULL;
615 
616 	if (fstat(fileno(orig), &sb) == -1)
617 		return got_error_from_errno("fstat");
618 
619 	copypos = 0;
620 	STAILQ_FOREACH(h, &p->head, entries) {
621 	tryagain:
622 		err = locate_hunk(orig, h, &pos, &lineno);
623 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
624 			h->err = err;
625 		if (err != NULL)
626 			return err;
627 		err = copy(tmp, orig, copypos, pos);
628 		if (err != NULL)
629 			return err;
630 		copypos = pos;
631 
632 		err = test_hunk(orig, h);
633 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
634 			/*
635 			 * try to apply the hunk again starting the search
636 			 * after the previous partial match.
637 			 */
638 			if (fseeko(orig, pos, SEEK_SET) == -1)
639 				return got_error_from_errno("fseeko");
640 			linelen = getline(&line, &linesize, orig);
641 			if (linelen == -1)
642 				return got_error_from_errno("getline");
643 			lineno++;
644 			goto tryagain;
645 		}
646 		if (err != NULL)
647 			return err;
648 
649 		if (lineno + 1 != h->old_from)
650 			h->offset = lineno + 1 - h->old_from;
651 
652 		err = apply_hunk(orig, tmp, h, &lineno, pos);
653 		if (err != NULL)
654 			return err;
655 
656 		copypos = ftello(orig);
657 		if (copypos == -1)
658 			return got_error_from_errno("ftello");
659 	}
660 
661 	if (p->new == NULL && sb.st_size != copypos) {
662 		h = STAILQ_FIRST(&p->head);
663 		h->err = got_error(GOT_ERR_HUNK_FAILED);
664 		err = h->err;
665 	} else if (!feof(orig))
666 		err = copy(tmp, orig, copypos, -1);
667 
668 	return err;
669 }
670 
671 static const struct got_error *
672 report_progress(struct patch_args *pa, const char *old, const char *new,
673     unsigned char status, const struct got_error *orig_error)
674 {
675 	const struct got_error *err;
676 	struct got_patch_hunk *h;
677 
678 	err = pa->progress_cb(pa->progress_arg, old, new, status,
679 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
680 	if (err)
681 		return err;
682 
683 	STAILQ_FOREACH(h, pa->head, entries) {
684 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
685 			continue;
686 
687 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
688 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
689 		    h->offset, h->ws_mangled, h->err);
690 		if (err)
691 			return err;
692 	}
693 
694 	return NULL;
695 }
696 
697 static const struct got_error *
698 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
699     const char *path)
700 {
701 	return report_progress(arg, path, NULL, status, NULL);
702 }
703 
704 static const struct got_error *
705 patch_add(void *arg, unsigned char status, const char *path)
706 {
707 	return report_progress(arg, NULL, path, status, NULL);
708 }
709 
710 static const struct got_error *
711 open_blob(char **path, FILE **fp, const char *blobid,
712     struct got_repository *repo)
713 {
714 	const struct got_error *err = NULL;
715 	struct got_blob_object *blob = NULL;
716 	struct got_object_id id, *idptr, *matched_id = NULL;
717 	int fd = -1;
718 
719 	*fp = NULL;
720 	*path = NULL;
721 
722 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
723 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
724 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
725 		    repo);
726 		if (err)
727 			return err;
728 		idptr = matched_id;
729 	} else {
730 		if (!got_parse_object_id(&id, blobid, GOT_HASH_SHA1))
731 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
732 		idptr = &id;
733 	}
734 
735 	fd = got_opentempfd();
736 	if (fd == -1) {
737 		err = got_error_from_errno("got_opentempfd");
738 		goto done;
739 	}
740 
741 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
742 	if (err)
743 		goto done;
744 
745 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob",
746 	    "");
747 	if (err)
748 		goto done;
749 
750 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
751 	if (err)
752 		goto done;
753 
754 done:
755 	if (fd != -1 && close(fd) == -1 && err == NULL)
756 		err = got_error_from_errno("close");
757 	if (blob)
758 		got_object_blob_close(blob);
759 	if (matched_id != NULL)
760 		free(matched_id);
761 	if (err) {
762 		if (*fp != NULL)
763 			fclose(*fp);
764 		if (*path != NULL)
765 			unlink(*path);
766 		free(*path);
767 		*fp = NULL;
768 		*path = NULL;
769 	}
770 	return err;
771 }
772 
773 static const struct got_error *
774 prepare_merge(int *do_merge, char **apath, FILE **afile,
775     struct got_worktree *worktree, struct got_repository *repo,
776     struct got_patch *p, struct got_object_id *commit_id,
777     struct got_tree_object *tree, const char *path)
778 {
779 	const struct got_error *err = NULL;
780 
781 	*do_merge = 0;
782 	*apath = NULL;
783 	*afile = NULL;
784 
785 	/* don't run the diff3 merge on creations/deletions */
786 	if (p->old == NULL || p->new == NULL)
787 		return NULL;
788 
789 	if (commit_id) {
790 		struct got_object_id *id;
791 
792 		err = got_object_tree_find_path(&id, NULL, repo, tree, path);
793 		if (err)
794 			return err;
795 		got_sha1_digest_to_str(id->sha1, p->blob, sizeof(p->blob));
796 		got_sha1_digest_to_str(commit_id->sha1, p->cid, sizeof(p->cid));
797 		free(id);
798 		err = open_blob(apath, afile, p->blob, repo);
799 		*do_merge = err == NULL;
800 	} else if (*p->blob != '\0') {
801 		err = open_blob(apath, afile, p->blob, repo);
802 		/*
803 		 * ignore failures to open this blob, we might have
804 		 * parsed gibberish.
805 		 */
806 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
807 		    err->code != GOT_ERR_NO_OBJ)
808 			return err;
809 		*do_merge = err == NULL;
810 		err = NULL;
811 	}
812 
813 	return err;
814 }
815 
816 static const struct got_error *
817 apply_patch(int *overlapcnt, struct got_worktree *worktree,
818     struct got_repository *repo, struct got_fileindex *fileindex,
819     const char *old, const char *new, struct got_patch *p, int nop,
820     int reverse, struct got_object_id *commit_id,
821     struct got_tree_object *tree, struct patch_args *pa,
822     got_cancel_cb cancel_cb, void *cancel_arg)
823 {
824 	const struct got_error *err = NULL;
825 	struct stat sb;
826 	int do_merge = 0, file_renamed = 0;
827 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
828 	char *oldpath = NULL, *newpath = NULL;
829 	char *tmppath = NULL, *template = NULL;
830 	char *apath = NULL, *mergepath = NULL;
831 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
832 	int outfd;
833 	mode_t mode = GOT_DEFAULT_FILE_MODE;
834 
835 	*overlapcnt = 0;
836 
837 	err = prepare_merge(&do_merge, &apath, &afile, worktree, repo, p,
838 	    commit_id, tree, old);
839 	if (err)
840 		return err;
841 
842 	if (reverse && !do_merge)
843 		reverse_patch(p);
844 
845 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
846 	    old) == -1) {
847 		err = got_error_from_errno("asprintf");
848 		goto done;
849 	}
850 
851 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
852 	    new) == -1) {
853 		err = got_error_from_errno("asprintf");
854 		goto done;
855 	}
856 
857 	file_renamed = strcmp(oldpath, newpath);
858 
859 	if (asprintf(&template, "%s/got-patch",
860 	    got_worktree_get_root_path(worktree)) == -1) {
861 		err = got_error_from_errno(template);
862 		goto done;
863 	}
864 
865 	if (p->old != NULL) {
866 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
867 			err = got_error_from_errno2("open", oldpath);
868 			goto done;
869 		}
870 		if (fstat(fileno(oldfile), &sb) == -1) {
871 			err = got_error_from_errno2("fstat", oldpath);
872 			goto done;
873 		}
874 		mode = sb.st_mode;
875 	} else if (p->xbit)
876 		mode |= (S_IXUSR | S_IXGRP | S_IXOTH);
877 
878 	err = got_opentemp_named(&tmppath, &tmpfile, template, "");
879 	if (err)
880 		goto done;
881 	outfd = fileno(tmpfile);
882 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
883 	if (err)
884 		goto done;
885 
886 	if (do_merge) {
887 		const char *type, *id;
888 
889 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
890 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
891 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
892 			err = got_error_from_errno("fseeko");
893 			goto done;
894 		}
895 
896 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
897 			err = got_error_from_errno("asprintf");
898 			oldlabel = NULL;
899 			goto done;
900 		}
901 
902 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
903 			err = got_error_from_errno("asprintf");
904 			newlabel = NULL;
905 			goto done;
906 		}
907 
908 		if (*p->cid != '\0') {
909 			type = "commit";
910 			id = p->cid;
911 		} else {
912 			type = "blob";
913 			id = p->blob;
914 		}
915 
916 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
917 			err = got_error_from_errno("asprintf");
918 			anclabel = NULL;
919 			goto done;
920 		}
921 
922 		if (reverse) {
923 			char *s;
924 			FILE *t;
925 
926 			s = anclabel;
927 			anclabel = newlabel;
928 			newlabel = s;
929 
930 			t = afile;
931 			afile = tmpfile;
932 			tmpfile = t;
933 		}
934 
935 		err = got_opentemp_named(&mergepath, &mergefile, template, "");
936 		if (err)
937 			goto done;
938 		outfd = fileno(mergefile);
939 
940 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
941 		    oldfile, oldlabel, anclabel, newlabel,
942 		    GOT_DIFF_ALGORITHM_PATIENCE);
943 		if (err)
944 			goto done;
945 	}
946 
947 	if (nop)
948 		goto done;
949 
950 	if (p->old != NULL && p->new == NULL) {
951 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
952 		    fileindex, patch_delete, pa);
953 		goto done;
954 	}
955 
956 	if (fchmod(outfd, apply_umask(mode)) == -1) {
957 		err = got_error_from_errno2("chmod", tmppath);
958 		goto done;
959 	}
960 
961 	if (mergepath) {
962 		err = got_path_move_file(mergepath, newpath);
963 		if (err)
964 			goto done;
965 		free(mergepath);
966 		mergepath = NULL;
967 	} else {
968 		err = got_path_move_file(tmppath, newpath);
969 		if (err)
970 			goto done;
971 		free(tmppath);
972 		tmppath = NULL;
973 	}
974 
975 	if (file_renamed) {
976 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
977 		    fileindex, patch_delete, pa);
978 		if (err == NULL)
979 			err = got_worktree_patch_schedule_add(new, repo,
980 			    worktree, fileindex, patch_add,
981 			    pa);
982 		if (err)
983 			unlink(newpath);
984 	} else if (p->old == NULL) {
985 		err = got_worktree_patch_schedule_add(new, repo, worktree,
986 		    fileindex, patch_add, pa);
987 		if (err)
988 			unlink(newpath);
989 	} else if (*overlapcnt != 0)
990 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
991 	else if (do_merge)
992 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
993 	else
994 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
995 
996 done:
997 	free(template);
998 
999 	if (tmppath != NULL && unlink(tmppath) == -1 && err == NULL)
1000 		err = got_error_from_errno("unlink");
1001 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
1002 		err = got_error_from_errno("fclose");
1003 	free(tmppath);
1004 
1005 	free(oldpath);
1006 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
1007 		err = got_error_from_errno("fclose");
1008 
1009 	if (apath != NULL && unlink(apath) == -1 && err == NULL)
1010 		err = got_error_from_errno("unlink");
1011 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
1012 		err = got_error_from_errno("fclose");
1013 	free(apath);
1014 
1015 	if (mergepath != NULL && unlink(mergepath) == -1 && err == NULL)
1016 		err = got_error_from_errno("unlink");
1017 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
1018 		err = got_error_from_errno("fclose");
1019 	free(mergepath);
1020 
1021 	free(newpath);
1022 	free(oldlabel);
1023 	free(newlabel);
1024 	free(anclabel);
1025 	return err;
1026 }
1027 
1028 const struct got_error *
1029 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
1030     int nop, int strip, int reverse, struct got_object_id *commit_id,
1031     got_patch_progress_cb progress_cb, void *progress_arg,
1032     got_cancel_cb cancel_cb, void *cancel_arg)
1033 {
1034 	const struct got_error *err = NULL, *complete_err = NULL;
1035 	struct got_fileindex *fileindex = NULL;
1036 	struct got_commit_object *commit = NULL;
1037 	struct got_tree_object *tree = NULL;
1038 	char *fileindex_path = NULL;
1039 	char *oldpath, *newpath;
1040 	struct imsgbuf *ibuf;
1041 	int imsg_fds[2] = {-1, -1};
1042 	int overlapcnt, done = 0, failed = 0;
1043 	pid_t pid;
1044 
1045 	ibuf = calloc(1, sizeof(*ibuf));
1046 	if (ibuf == NULL) {
1047 		err = got_error_from_errno("calloc");
1048 		goto done;
1049 	}
1050 
1051 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1052 		err = got_error_from_errno("socketpair");
1053 		goto done;
1054 	}
1055 
1056 	pid = fork();
1057 	if (pid == -1) {
1058 		err = got_error_from_errno("fork");
1059 		goto done;
1060 	} else if (pid == 0) {
1061 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
1062 		    NULL);
1063 		/* not reached */
1064 	}
1065 
1066 	if (close(imsg_fds[1]) == -1) {
1067 		err = got_error_from_errno("close");
1068 		goto done;
1069 	}
1070 	imsg_fds[1] = -1;
1071 	imsg_init(ibuf, imsg_fds[0]);
1072 
1073 	err = send_patch(ibuf, fd);
1074 	fd = -1;
1075 	if (err)
1076 		goto done;
1077 
1078 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
1079 	    worktree);
1080 	if (err)
1081 		goto done;
1082 
1083 	if (commit_id) {
1084 		err = got_object_open_as_commit(&commit, repo, commit_id);
1085 		if (err)
1086 			goto done;
1087 
1088 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1089 		if (err)
1090 			goto done;
1091 	}
1092 
1093 	while (!done && err == NULL) {
1094 		struct got_patch p;
1095 		struct patch_args pa;
1096 
1097 		pa.progress_cb = progress_cb;
1098 		pa.progress_arg = progress_arg;
1099 		pa.head = &p.head;
1100 
1101 		err = recv_patch(ibuf, &done, &p, strip);
1102 		if (err || done)
1103 			break;
1104 
1105 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1106 		    &newpath, worktree, repo, fileindex);
1107 		if (err == NULL)
1108 			err = apply_patch(&overlapcnt, worktree, repo,
1109 			    fileindex, oldpath, newpath, &p, nop, reverse,
1110 			    commit_id, tree, &pa, cancel_cb, cancel_arg);
1111 		if (err != NULL) {
1112 			failed = 1;
1113 			/* recoverable errors */
1114 			if (err->code == GOT_ERR_FILE_STATUS ||
1115 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1116 				err = report_progress(&pa, p.old, p.new,
1117 				    GOT_STATUS_CANNOT_UPDATE, err);
1118 			else if (err->code == GOT_ERR_HUNK_FAILED)
1119 				err = report_progress(&pa, p.old, p.new,
1120 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1121 		}
1122 		if (overlapcnt != 0)
1123 			failed = 1;
1124 
1125 		free(oldpath);
1126 		free(newpath);
1127 		patch_free(&p);
1128 
1129 		if (err)
1130 			break;
1131 	}
1132 
1133 done:
1134 	if (fileindex != NULL)
1135 		complete_err = got_worktree_patch_complete(fileindex,
1136 		    fileindex_path);
1137 	if (complete_err && err == NULL)
1138 		err = complete_err;
1139 	free(fileindex_path);
1140 	if (tree)
1141 		got_object_tree_close(tree);
1142 	if (commit)
1143 		got_object_commit_close(commit);
1144 	if (fd != -1 && close(fd) == -1 && err == NULL)
1145 		err = got_error_from_errno("close");
1146 	if (ibuf != NULL)
1147 		imsg_clear(ibuf);
1148 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1149 		err = got_error_from_errno("close");
1150 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1151 		err = got_error_from_errno("close");
1152 	if (err == NULL && failed)
1153 		err = got_error(GOT_ERR_PATCH_FAILED);
1154 	return err;
1155 }