1 /*
2  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  *
16  * Apply patches.
17  *
18  * Things that we may want to support:
19  *     + support indented patches?
20  *     + support other kinds of patches?
21  */
22 
23 #include <sys/types.h>
24 #include <sys/queue.h>
25 #include <sys/socket.h>
26 #include <sys/stat.h>
27 #include <sys/uio.h>
28 
29 #include <ctype.h>
30 #include <errno.h>
31 #include <limits.h>
32 #include <sha1.h>
33 #include <sha2.h>
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39 #include <imsg.h>
40 
41 #include "got_error.h"
42 #include "got_object.h"
43 #include "got_path.h"
44 #include "got_reference.h"
45 #include "got_cancel.h"
46 #include "got_worktree.h"
47 #include "got_repository.h"
48 #include "got_opentemp.h"
49 #include "got_patch.h"
50 #include "got_diff.h"
51 
52 #include "got_lib_delta.h"
53 #include "got_lib_diff.h"
54 #include "got_lib_object.h"
55 #include "got_lib_privsep.h"
56 #include "got_lib_hash.h"
57 
58 #ifndef MIN
59 #define MIN(a, b) ((a) < (b) ? (a) : (b))
60 #endif
61 
62 struct got_patch_line {
63 	char	 mode;
64 	char	*line;
65 	size_t	 len;
66 };
67 
68 struct got_patch_hunk {
69 	STAILQ_ENTRY(got_patch_hunk) entries;
70 	const struct got_error *err;
71 	int	ws_mangled;
72 	int	offset;
73 	int	old_nonl;
74 	int	new_nonl;
75 	int	old_from;
76 	int	old_lines;
77 	int	new_from;
78 	int	new_lines;
79 	size_t	len;
80 	size_t	cap;
81 	struct got_patch_line *lines;
82 };
83 
84 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
85 struct got_patch {
86 	int	 xbit;
87 	char	*old;
88 	char	*new;
89 	char	 cid[41];
90 	char	 blob[41];
91 	struct got_patch_hunk_head head;
92 };
93 
94 struct patch_args {
95 	got_patch_progress_cb progress_cb;
96 	void	*progress_arg;
97 	struct got_patch_hunk_head *head;
98 };
99 
100 static mode_t
101 apply_umask(mode_t mode)
102 {
103 	mode_t um;
104 
105 	um = umask(000);
106 	umask(um);
107 	return mode & ~um;
108 }
109 
110 static const struct got_error *
111 send_patch(struct imsgbuf *ibuf, int fd)
112 {
113 	const struct got_error *err = NULL;
114 
115 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
116 	    NULL, 0) == -1) {
117 		err = got_error_from_errno(
118 		    "imsg_compose GOT_IMSG_PATCH_FILE");
119 		close(fd);
120 		return err;
121 	}
122 
123 	return got_privsep_flush_imsg(ibuf);
124 }
125 
126 static void
127 patch_free(struct got_patch *p)
128 {
129 	struct got_patch_hunk *h;
130 	size_t i;
131 
132 	while (!STAILQ_EMPTY(&p->head)) {
133 		h = STAILQ_FIRST(&p->head);
134 		STAILQ_REMOVE_HEAD(&p->head, entries);
135 
136 		for (i = 0; i < h->len; ++i)
137 			free(h->lines[i].line);
138 		free(h->lines);
139 		free(h);
140 	}
141 
142 	free(p->new);
143 	free(p->old);
144 
145 	memset(p, 0, sizeof(*p));
146 	STAILQ_INIT(&p->head);
147 }
148 
149 static const struct got_error *
150 pushline(struct got_patch_hunk *h, const char *line, size_t len)
151 {
152 	void 	*t;
153 	size_t	 newcap;
154 
155 	if (h->len == h->cap) {
156 		if ((newcap = h->cap * 1.5) == 0)
157 			newcap = 16;
158 		t = recallocarray(h->lines, h->cap, newcap,
159 		    sizeof(h->lines[0]));
160 		if (t == NULL)
161 			return got_error_from_errno("recallocarray");
162 		h->lines = t;
163 		h->cap = newcap;
164 	}
165 
166 	if ((t = malloc(len - 1)) == NULL)
167 		return got_error_from_errno("malloc");
168 	memcpy(t, line + 1, len - 1);	/* skip the line type */
169 
170 	h->lines[h->len].mode = *line;
171 	h->lines[h->len].line = t;
172 	h->lines[h->len].len = len - 2;	/* line type and trailing NUL */
173 	h->len++;
174 	return NULL;
175 }
176 
177 static const struct got_error *
178 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
179 {
180 	const struct got_error *err = NULL;
181 	struct imsg imsg;
182 	struct got_imsg_patch_hunk hdr;
183 	struct got_imsg_patch patch;
184 	struct got_patch_hunk *h = NULL;
185 	size_t datalen;
186 	int lastmode = -1;
187 
188 	memset(p, 0, sizeof(*p));
189 	STAILQ_INIT(&p->head);
190 
191 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
192 	if (err)
193 		return err;
194 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
195 		*done = 1;
196 		goto done;
197 	}
198 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
199 		err = got_error(GOT_ERR_PRIVSEP_MSG);
200 		goto done;
201 	}
202 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
203 	if (datalen != sizeof(patch)) {
204 		err = got_error(GOT_ERR_PRIVSEP_LEN);
205 		goto done;
206 	}
207 	memcpy(&patch, imsg.data, sizeof(patch));
208 
209 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
210 	    patch.new[sizeof(patch.new)-1] != '\0' ||
211 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
212 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
213 		err = got_error(GOT_ERR_PRIVSEP_LEN);
214 		goto done;
215 	}
216 
217 	if (*patch.cid != '\0')
218 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
219 
220 	if (*patch.blob != '\0')
221 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
222 
223 	p->xbit = patch.xbit;
224 
225 	/* automatically set strip=1 for git-style diffs */
226 	if (strip == -1 && patch.git &&
227 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
228 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
229 		strip = 1;
230 
231 	/* prefer the new name if not /dev/null for not git-style diffs */
232 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
233 		err = got_path_strip(&p->old, patch.new, strip);
234 		if (err)
235 			goto done;
236 	} else if (*patch.old != '\0') {
237 		err = got_path_strip(&p->old, patch.old, strip);
238 		if (err)
239 			goto done;
240 	}
241 
242 	if (*patch.new != '\0') {
243 		err = got_path_strip(&p->new, patch.new, strip);
244 		if (err)
245 			goto done;
246 	}
247 
248 	if (p->old == NULL && p->new == NULL) {
249 		err = got_error(GOT_ERR_PATCH_MALFORMED);
250 		goto done;
251 	}
252 
253 	imsg_free(&imsg);
254 
255 	for (;;) {
256 		char *t;
257 
258 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
259 		if (err) {
260 			patch_free(p);
261 			return err;
262 		}
263 
264 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
265 		switch (imsg.hdr.type) {
266 		case GOT_IMSG_PATCH_DONE:
267 			if (h != NULL && h->len == 0)
268 				err = got_error(GOT_ERR_PATCH_MALFORMED);
269 			goto done;
270 		case GOT_IMSG_PATCH_HUNK:
271 			if (h != NULL &&
272 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
273 				err = got_error(GOT_ERR_PATCH_MALFORMED);
274 				goto done;
275 			}
276 			lastmode = -1;
277 			if (datalen != sizeof(hdr)) {
278 				err = got_error(GOT_ERR_PRIVSEP_LEN);
279 				goto done;
280 			}
281 			memcpy(&hdr, imsg.data, sizeof(hdr));
282 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
283 				err = got_error(GOT_ERR_PRIVSEP_LEN);
284 				goto done;
285 			}
286 			if ((h = calloc(1, sizeof(*h))) == NULL) {
287 				err = got_error_from_errno("calloc");
288 				goto done;
289 			}
290 			h->old_from = hdr.oldfrom;
291 			h->old_lines = hdr.oldlines;
292 			h->new_from = hdr.newfrom;
293 			h->new_lines = hdr.newlines;
294 			STAILQ_INSERT_TAIL(&p->head, h, entries);
295 			break;
296 		case GOT_IMSG_PATCH_LINE:
297 			if (h == NULL) {
298 				err = got_error(GOT_ERR_PRIVSEP_MSG);
299 				goto done;
300 			}
301 			t = imsg.data;
302 			/* at least one char */
303 			if (datalen < 2 || t[datalen-1] != '\0') {
304 				err = got_error(GOT_ERR_PRIVSEP_MSG);
305 				goto done;
306 			}
307 			if (*t != ' ' && *t != '-' && *t != '+' &&
308 			    *t != '\\') {
309 				err = got_error(GOT_ERR_PRIVSEP_MSG);
310 				goto done;
311 			}
312 
313 			if (*t != '\\')
314 				err = pushline(h, t, datalen);
315 			else if (lastmode == '-')
316 				h->old_nonl = 1;
317 			else if (lastmode == '+')
318 				h->new_nonl = 1;
319 			else
320 				err = got_error(GOT_ERR_PATCH_MALFORMED);
321 
322 			if (err)
323 				goto done;
324 
325 			lastmode = *t;
326 			break;
327 		default:
328 			err = got_error(GOT_ERR_PRIVSEP_MSG);
329 			goto done;
330 		}
331 
332 		imsg_free(&imsg);
333 	}
334 
335 done:
336 	if (err)
337 		patch_free(p);
338 
339 	imsg_free(&imsg);
340 	return err;
341 }
342 
343 static void
344 reverse_patch(struct got_patch *p)
345 {
346 	struct got_patch_hunk *h;
347 	size_t i;
348 	int tmp;
349 
350 	STAILQ_FOREACH(h, &p->head, entries) {
351 		tmp = h->old_from;
352 		h->old_from = h->new_from;
353 		h->new_from = tmp;
354 
355 		tmp = h->old_lines;
356 		h->old_lines = h->new_lines;
357 		h->new_lines = tmp;
358 
359 		tmp = h->old_nonl;
360 		h->old_nonl = h->new_nonl;
361 		h->new_nonl = tmp;
362 
363 		for (i = 0; i < h->len; ++i) {
364 			if (h->lines[i].mode == '+')
365 				h->lines[i].mode = '-';
366 			else if (h->lines[i].mode == '-')
367 				h->lines[i].mode = '+';
368 		}
369 	}
370 }
371 
372 /*
373  * Copy data from orig starting at copypos until pos into tmp.
374  * If pos is -1, copy until EOF.
375  */
376 static const struct got_error *
377 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
378 {
379 	char buf[BUFSIZ];
380 	size_t len, r, w;
381 
382 	if (fseeko(orig, copypos, SEEK_SET) == -1)
383 		return got_error_from_errno("fseeko");
384 
385 	while (pos == -1 || copypos < pos) {
386 		len = sizeof(buf);
387 		if (pos > 0)
388 			len = MIN(len, (size_t)pos - copypos);
389 		r = fread(buf, 1, len, orig);
390 		if (r != len && ferror(orig))
391 			return got_error_from_errno("fread");
392 		w = fwrite(buf, 1, r, tmp);
393 		if (w != r)
394 			return got_error_from_errno("fwrite");
395 		copypos += len;
396 		if (r != len && feof(orig)) {
397 			if (pos == -1)
398 				return NULL;
399 			return got_error(GOT_ERR_HUNK_FAILED);
400 		}
401 	}
402 	return NULL;
403 }
404 
405 static int lines_eq(struct got_patch_line *, const char *, size_t, int *);
406 
407 static const struct got_error *
408 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
409 {
410 	const struct got_error *err = NULL;
411 	struct got_patch_line *l = &h->lines[0];
412 	char *line = NULL;
413 	char mode = l->mode;
414 	size_t linesize = 0;
415 	ssize_t linelen;
416 	off_t match = -1;
417 	int mangled = 0, match_lineno = -1;
418 
419 	for (;;) {
420 		linelen = getline(&line, &linesize, orig);
421 		if (linelen == -1) {
422 			if (ferror(orig))
423 				err = got_error_from_errno("getline");
424 			else if (match == -1)
425 				err = got_error(GOT_ERR_HUNK_FAILED);
426 			break;
427 		}
428 		(*lineno)++;
429 
430 		if ((mode == ' ' && lines_eq(l, line, linelen, &mangled)) ||
431 		    (mode == '-' && lines_eq(l, line, linelen, &mangled)) ||
432 		    (mode == '+' && *lineno == h->old_from)) {
433 			match = ftello(orig);
434 			if (match == -1) {
435 				err = got_error_from_errno("ftello");
436 				break;
437 			}
438 			match -= linelen;
439 			match_lineno = (*lineno)-1;
440 		}
441 
442 		if (*lineno >= h->old_from && match != -1) {
443 			if (mangled)
444 				h->ws_mangled = 1;
445 			break;
446 		}
447 	}
448 
449 	if (err == NULL) {
450 		*pos = match;
451 		*lineno = match_lineno;
452 		if (fseeko(orig, match, SEEK_SET) == -1)
453 			err = got_error_from_errno("fseeko");
454 	}
455 
456 	free(line);
457 	return err;
458 }
459 
460 static int
461 lines_eq(struct got_patch_line *l, const char *b, size_t len, int *mangled)
462 {
463 	char *a = l->line;
464 	size_t i, j;
465 
466 	if (len > 00 && b[len - 1] == '\n')
467 		len--;
468 
469 	*mangled = 0;
470 	if (l->len == len && !memcmp(a, b, len))
471 		return 1;
472 
473 	*mangled = 1;
474 
475 	i = j = 0;
476 	for (;;) {
477 		while (i < l->len &&
478 		    (a[i] == '\t' || a[i] == ' ' || a[i] == '\f'))
479 			i++;
480 		while (j < len &&
481 		    (b[j] == '\t' || b[j] == ' ' || b[j] == '\f'))
482 			j++;
483 		if (i == l->len || j == len || a[i] != b[j])
484 			break;
485 		i++, j++;
486 	}
487 
488 	return (i == l->len && j == len);
489 }
490 
491 static const struct got_error *
492 test_hunk(FILE *orig, struct got_patch_hunk *h)
493 {
494 	const struct got_error *err = NULL;
495 	char *line = NULL;
496 	size_t linesize = 0, i = 0;
497 	ssize_t linelen;
498 	int mangled;
499 
500 	for (i = 0; i < h->len; ++i) {
501 		switch (h->lines[i].mode) {
502 		case '+':
503 			continue;
504 		case ' ':
505 		case '-':
506 			linelen = getline(&line, &linesize, orig);
507 			if (linelen == -1) {
508 				if (ferror(orig))
509 					err = got_error_from_errno("getline");
510 				else
511 					err = got_error(
512 					    GOT_ERR_HUNK_FAILED);
513 				goto done;
514 			}
515 			if (!lines_eq(&h->lines[i], line, linelen, &mangled)) {
516 				err = got_error(GOT_ERR_HUNK_FAILED);
517 				goto done;
518 			}
519 			if (mangled)
520 				h->ws_mangled = 1;
521 			break;
522 		}
523 	}
524 
525 done:
526 	free(line);
527 	return err;
528 }
529 
530 static const struct got_error *
531 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
532     off_t from)
533 {
534 	const struct got_error *err = NULL;
535 	const char *t;
536 	size_t linesize = 0, i, new = 0;
537 	char *line = NULL;
538 	char mode;
539 	size_t l;
540 	ssize_t linelen;
541 
542 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
543 		return got_error_from_errno("fseeko");
544 
545 	for (i = 0; i < h->len; ++i) {
546 		switch (mode = h->lines[i].mode) {
547 		case '-':
548 		case ' ':
549 			(*lineno)++;
550 			if (orig != NULL) {
551 				linelen = getline(&line, &linesize, orig);
552 				if (linelen == -1) {
553 					err = got_error_from_errno("getline");
554 					goto done;
555 				}
556 				if (line[linelen - 1] == '\n')
557 					line[linelen - 1] = '\0';
558 				t = line;
559 				l = linelen - 1;
560 			} else {
561 				t = h->lines[i].line;
562 				l = h->lines[i].len;
563 			}
564 			if (mode == '-')
565 				continue;
566 			if (fwrite(t, 1, l, tmp) != l ||
567 			    fputc('\n', tmp) == EOF) {
568 				err = got_error_from_errno("fprintf");
569 				goto done;
570 			}
571 			break;
572 		case '+':
573 			new++;
574 			t = h->lines[i].line;
575 			l = h->lines[i].len;
576 			if (fwrite(t, 1, l, tmp) != l) {
577 				err = got_error_from_errno("fprintf");
578 				goto done;
579 			}
580 			if (new != h->new_lines || !h->new_nonl) {
581 				if (fprintf(tmp, "\n") < 0) {
582 					err = got_error_from_errno("fprintf");
583 					goto done;
584 				}
585 			}
586 			break;
587 		}
588 	}
589 
590 done:
591 	free(line);
592 	return err;
593 }
594 
595 static const struct got_error *
596 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
597 {
598 	const struct got_error *err = NULL;
599 	struct got_patch_hunk *h;
600 	struct stat sb;
601 	int lineno = 0;
602 	off_t copypos, pos;
603 	char *line = NULL;
604 	size_t linesize = 0;
605 	ssize_t linelen;
606 
607 	if (p->old == NULL) {				/* create */
608 		h = STAILQ_FIRST(&p->head);
609 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
610 			return got_error(GOT_ERR_PATCH_MALFORMED);
611 		return apply_hunk(orig, tmp, h, &lineno, 0);
612 	}
613 
614 	/* When deleting binary files there are no hunks to apply. */
615 	if (p->new == NULL && STAILQ_EMPTY(&p->head))
616 		return NULL;
617 
618 	if (fstat(fileno(orig), &sb) == -1)
619 		return got_error_from_errno("fstat");
620 
621 	copypos = 0;
622 	STAILQ_FOREACH(h, &p->head, entries) {
623 	tryagain:
624 		err = locate_hunk(orig, h, &pos, &lineno);
625 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
626 			h->err = err;
627 		if (err != NULL)
628 			return err;
629 		err = copy(tmp, orig, copypos, pos);
630 		if (err != NULL)
631 			return err;
632 		copypos = pos;
633 
634 		err = test_hunk(orig, h);
635 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
636 			/*
637 			 * try to apply the hunk again starting the search
638 			 * after the previous partial match.
639 			 */
640 			if (fseeko(orig, pos, SEEK_SET) == -1)
641 				return got_error_from_errno("fseeko");
642 			linelen = getline(&line, &linesize, orig);
643 			if (linelen == -1)
644 				return got_error_from_errno("getline");
645 			lineno++;
646 			goto tryagain;
647 		}
648 		if (err != NULL)
649 			return err;
650 
651 		if (lineno + 1 != h->old_from)
652 			h->offset = lineno + 1 - h->old_from;
653 
654 		err = apply_hunk(orig, tmp, h, &lineno, pos);
655 		if (err != NULL)
656 			return err;
657 
658 		copypos = ftello(orig);
659 		if (copypos == -1)
660 			return got_error_from_errno("ftello");
661 	}
662 
663 	if (p->new == NULL && sb.st_size != copypos) {
664 		h = STAILQ_FIRST(&p->head);
665 		h->err = got_error(GOT_ERR_HUNK_FAILED);
666 		err = h->err;
667 	} else if (!feof(orig))
668 		err = copy(tmp, orig, copypos, -1);
669 
670 	return err;
671 }
672 
673 static const struct got_error *
674 report_progress(struct patch_args *pa, const char *old, const char *new,
675     unsigned char status, const struct got_error *orig_error)
676 {
677 	const struct got_error *err;
678 	struct got_patch_hunk *h;
679 
680 	err = pa->progress_cb(pa->progress_arg, old, new, status,
681 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
682 	if (err)
683 		return err;
684 
685 	STAILQ_FOREACH(h, pa->head, entries) {
686 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
687 			continue;
688 
689 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
690 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
691 		    h->offset, h->ws_mangled, h->err);
692 		if (err)
693 			return err;
694 	}
695 
696 	return NULL;
697 }
698 
699 static const struct got_error *
700 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
701     const char *path)
702 {
703 	return report_progress(arg, path, NULL, status, NULL);
704 }
705 
706 static const struct got_error *
707 patch_add(void *arg, unsigned char status, const char *path)
708 {
709 	return report_progress(arg, NULL, path, status, NULL);
710 }
711 
712 static const struct got_error *
713 open_blob(char **path, FILE **fp, const char *blobid,
714     struct got_repository *repo)
715 {
716 	const struct got_error *err = NULL;
717 	struct got_blob_object *blob = NULL;
718 	struct got_object_id id, *idptr, *matched_id = NULL;
719 	int fd = -1;
720 
721 	*fp = NULL;
722 	*path = NULL;
723 
724 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
725 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
726 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
727 		    repo);
728 		if (err)
729 			return err;
730 		idptr = matched_id;
731 	} else {
732 		if (!got_parse_object_id(&id, blobid, GOT_HASH_SHA1))
733 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
734 		idptr = &id;
735 	}
736 
737 	fd = got_opentempfd();
738 	if (fd == -1) {
739 		err = got_error_from_errno("got_opentempfd");
740 		goto done;
741 	}
742 
743 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
744 	if (err)
745 		goto done;
746 
747 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob",
748 	    "");
749 	if (err)
750 		goto done;
751 
752 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
753 	if (err)
754 		goto done;
755 
756 done:
757 	if (fd != -1 && close(fd) == -1 && err == NULL)
758 		err = got_error_from_errno("close");
759 	if (blob)
760 		got_object_blob_close(blob);
761 	if (matched_id != NULL)
762 		free(matched_id);
763 	if (err) {
764 		if (*fp != NULL)
765 			fclose(*fp);
766 		if (*path != NULL)
767 			unlink(*path);
768 		free(*path);
769 		*fp = NULL;
770 		*path = NULL;
771 	}
772 	return err;
773 }
774 
775 static const struct got_error *
776 prepare_merge(int *do_merge, char **apath, FILE **afile,
777     struct got_worktree *worktree, struct got_repository *repo,
778     struct got_patch *p, struct got_object_id *commit_id,
779     struct got_tree_object *tree, const char *path)
780 {
781 	const struct got_error *err = NULL;
782 
783 	*do_merge = 0;
784 	*apath = NULL;
785 	*afile = NULL;
786 
787 	/* don't run the diff3 merge on creations/deletions */
788 	if (p->old == NULL || p->new == NULL)
789 		return NULL;
790 
791 	if (commit_id) {
792 		struct got_object_id *id;
793 
794 		err = got_object_tree_find_path(&id, NULL, repo, tree, path);
795 		if (err)
796 			return err;
797 		got_sha1_digest_to_str(id->sha1, p->blob, sizeof(p->blob));
798 		got_sha1_digest_to_str(commit_id->sha1, p->cid, sizeof(p->cid));
799 		free(id);
800 		err = open_blob(apath, afile, p->blob, repo);
801 		*do_merge = err == NULL;
802 	} else if (*p->blob != '\0') {
803 		err = open_blob(apath, afile, p->blob, repo);
804 		/*
805 		 * ignore failures to open this blob, we might have
806 		 * parsed gibberish.
807 		 */
808 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
809 		    err->code != GOT_ERR_NO_OBJ)
810 			return err;
811 		*do_merge = err == NULL;
812 		err = NULL;
813 	}
814 
815 	return err;
816 }
817 
818 static const struct got_error *
819 apply_patch(int *overlapcnt, struct got_worktree *worktree,
820     struct got_repository *repo, struct got_fileindex *fileindex,
821     const char *old, const char *new, struct got_patch *p, int nop,
822     int reverse, struct got_object_id *commit_id,
823     struct got_tree_object *tree, struct patch_args *pa,
824     got_cancel_cb cancel_cb, void *cancel_arg)
825 {
826 	const struct got_error *err = NULL;
827 	struct stat sb;
828 	int do_merge = 0, file_renamed = 0;
829 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
830 	char *oldpath = NULL, *newpath = NULL;
831 	char *tmppath = NULL, *template = NULL;
832 	char *apath = NULL, *mergepath = NULL;
833 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
834 	int outfd;
835 	mode_t mode = GOT_DEFAULT_FILE_MODE;
836 
837 	*overlapcnt = 0;
838 
839 	err = prepare_merge(&do_merge, &apath, &afile, worktree, repo, p,
840 	    commit_id, tree, old);
841 	if (err)
842 		return err;
843 
844 	if (reverse && !do_merge)
845 		reverse_patch(p);
846 
847 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
848 	    old) == -1) {
849 		err = got_error_from_errno("asprintf");
850 		goto done;
851 	}
852 
853 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
854 	    new) == -1) {
855 		err = got_error_from_errno("asprintf");
856 		goto done;
857 	}
858 
859 	file_renamed = strcmp(oldpath, newpath);
860 
861 	if (asprintf(&template, "%s/got-patch",
862 	    got_worktree_get_root_path(worktree)) == -1) {
863 		err = got_error_from_errno(template);
864 		goto done;
865 	}
866 
867 	if (p->old != NULL) {
868 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
869 			err = got_error_from_errno2("open", oldpath);
870 			goto done;
871 		}
872 		if (fstat(fileno(oldfile), &sb) == -1) {
873 			err = got_error_from_errno2("fstat", oldpath);
874 			goto done;
875 		}
876 		mode = sb.st_mode;
877 	} else if (p->xbit)
878 		mode |= (S_IXUSR | S_IXGRP | S_IXOTH);
879 
880 	err = got_opentemp_named(&tmppath, &tmpfile, template, "");
881 	if (err)
882 		goto done;
883 	outfd = fileno(tmpfile);
884 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
885 	if (err)
886 		goto done;
887 
888 	if (do_merge) {
889 		const char *type, *id;
890 
891 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
892 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
893 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
894 			err = got_error_from_errno("fseeko");
895 			goto done;
896 		}
897 
898 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
899 			err = got_error_from_errno("asprintf");
900 			oldlabel = NULL;
901 			goto done;
902 		}
903 
904 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
905 			err = got_error_from_errno("asprintf");
906 			newlabel = NULL;
907 			goto done;
908 		}
909 
910 		if (*p->cid != '\0') {
911 			type = "commit";
912 			id = p->cid;
913 		} else {
914 			type = "blob";
915 			id = p->blob;
916 		}
917 
918 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
919 			err = got_error_from_errno("asprintf");
920 			anclabel = NULL;
921 			goto done;
922 		}
923 
924 		if (reverse) {
925 			char *s;
926 			FILE *t;
927 
928 			s = anclabel;
929 			anclabel = newlabel;
930 			newlabel = s;
931 
932 			t = afile;
933 			afile = tmpfile;
934 			tmpfile = t;
935 		}
936 
937 		err = got_opentemp_named(&mergepath, &mergefile, template, "");
938 		if (err)
939 			goto done;
940 		outfd = fileno(mergefile);
941 
942 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
943 		    oldfile, oldlabel, anclabel, newlabel,
944 		    GOT_DIFF_ALGORITHM_PATIENCE);
945 		if (err)
946 			goto done;
947 	}
948 
949 	if (nop)
950 		goto done;
951 
952 	if (p->old != NULL && p->new == NULL) {
953 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
954 		    fileindex, patch_delete, pa);
955 		goto done;
956 	}
957 
958 	if (fchmod(outfd, apply_umask(mode)) == -1) {
959 		err = got_error_from_errno2("chmod", tmppath);
960 		goto done;
961 	}
962 
963 	if (mergepath) {
964 		err = got_path_move_file(mergepath, newpath);
965 		if (err)
966 			goto done;
967 		free(mergepath);
968 		mergepath = NULL;
969 	} else {
970 		err = got_path_move_file(tmppath, newpath);
971 		if (err)
972 			goto done;
973 		free(tmppath);
974 		tmppath = NULL;
975 	}
976 
977 	if (file_renamed) {
978 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
979 		    fileindex, patch_delete, pa);
980 		if (err == NULL)
981 			err = got_worktree_patch_schedule_add(new, repo,
982 			    worktree, fileindex, patch_add,
983 			    pa);
984 		if (err)
985 			unlink(newpath);
986 	} else if (p->old == NULL) {
987 		err = got_worktree_patch_schedule_add(new, repo, worktree,
988 		    fileindex, patch_add, pa);
989 		if (err)
990 			unlink(newpath);
991 	} else if (*overlapcnt != 0)
992 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
993 	else if (do_merge)
994 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
995 	else
996 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
997 
998 done:
999 	free(template);
1000 
1001 	if (tmppath != NULL && unlink(tmppath) == -1 && err == NULL)
1002 		err = got_error_from_errno("unlink");
1003 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
1004 		err = got_error_from_errno("fclose");
1005 	free(tmppath);
1006 
1007 	free(oldpath);
1008 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
1009 		err = got_error_from_errno("fclose");
1010 
1011 	if (apath != NULL && unlink(apath) == -1 && err == NULL)
1012 		err = got_error_from_errno("unlink");
1013 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
1014 		err = got_error_from_errno("fclose");
1015 	free(apath);
1016 
1017 	if (mergepath != NULL && unlink(mergepath) == -1 && err == NULL)
1018 		err = got_error_from_errno("unlink");
1019 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
1020 		err = got_error_from_errno("fclose");
1021 	free(mergepath);
1022 
1023 	free(newpath);
1024 	free(oldlabel);
1025 	free(newlabel);
1026 	free(anclabel);
1027 	return err;
1028 }
1029 
1030 const struct got_error *
1031 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
1032     int nop, int strip, int reverse, struct got_object_id *commit_id,
1033     got_patch_progress_cb progress_cb, void *progress_arg,
1034     got_cancel_cb cancel_cb, void *cancel_arg)
1035 {
1036 	const struct got_error *err = NULL, *complete_err = NULL;
1037 	struct got_fileindex *fileindex = NULL;
1038 	struct got_commit_object *commit = NULL;
1039 	struct got_tree_object *tree = NULL;
1040 	char *fileindex_path = NULL;
1041 	char *oldpath, *newpath;
1042 	struct imsgbuf *ibuf;
1043 	int imsg_fds[2] = {-1, -1};
1044 	int overlapcnt, done = 0, failed = 0;
1045 	pid_t pid;
1046 
1047 	ibuf = calloc(1, sizeof(*ibuf));
1048 	if (ibuf == NULL) {
1049 		err = got_error_from_errno("calloc");
1050 		goto done;
1051 	}
1052 
1053 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1054 		err = got_error_from_errno("socketpair");
1055 		goto done;
1056 	}
1057 
1058 	pid = fork();
1059 	if (pid == -1) {
1060 		err = got_error_from_errno("fork");
1061 		goto done;
1062 	} else if (pid == 0) {
1063 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
1064 		    NULL);
1065 		/* not reached */
1066 	}
1067 
1068 	if (close(imsg_fds[1]) == -1) {
1069 		err = got_error_from_errno("close");
1070 		goto done;
1071 	}
1072 	imsg_fds[1] = -1;
1073 	imsg_init(ibuf, imsg_fds[0]);
1074 
1075 	err = send_patch(ibuf, fd);
1076 	fd = -1;
1077 	if (err)
1078 		goto done;
1079 
1080 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
1081 	    worktree);
1082 	if (err)
1083 		goto done;
1084 
1085 	if (commit_id) {
1086 		err = got_object_open_as_commit(&commit, repo, commit_id);
1087 		if (err)
1088 			goto done;
1089 
1090 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1091 		if (err)
1092 			goto done;
1093 	}
1094 
1095 	while (!done && err == NULL) {
1096 		struct got_patch p;
1097 		struct patch_args pa;
1098 
1099 		pa.progress_cb = progress_cb;
1100 		pa.progress_arg = progress_arg;
1101 		pa.head = &p.head;
1102 
1103 		err = recv_patch(ibuf, &done, &p, strip);
1104 		if (err || done)
1105 			break;
1106 
1107 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1108 		    &newpath, worktree, repo, fileindex);
1109 		if (err == NULL)
1110 			err = apply_patch(&overlapcnt, worktree, repo,
1111 			    fileindex, oldpath, newpath, &p, nop, reverse,
1112 			    commit_id, tree, &pa, cancel_cb, cancel_arg);
1113 		if (err != NULL) {
1114 			failed = 1;
1115 			/* recoverable errors */
1116 			if (err->code == GOT_ERR_FILE_STATUS ||
1117 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1118 				err = report_progress(&pa, p.old, p.new,
1119 				    GOT_STATUS_CANNOT_UPDATE, err);
1120 			else if (err->code == GOT_ERR_HUNK_FAILED)
1121 				err = report_progress(&pa, p.old, p.new,
1122 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1123 		}
1124 		if (overlapcnt != 0)
1125 			failed = 1;
1126 
1127 		free(oldpath);
1128 		free(newpath);
1129 		patch_free(&p);
1130 
1131 		if (err)
1132 			break;
1133 	}
1134 
1135 done:
1136 	if (fileindex != NULL)
1137 		complete_err = got_worktree_patch_complete(fileindex,
1138 		    fileindex_path);
1139 	if (complete_err && err == NULL)
1140 		err = complete_err;
1141 	free(fileindex_path);
1142 	if (tree)
1143 		got_object_tree_close(tree);
1144 	if (commit)
1145 		got_object_commit_close(commit);
1146 	if (fd != -1 && close(fd) == -1 && err == NULL)
1147 		err = got_error_from_errno("close");
1148 	if (ibuf != NULL)
1149 		imsg_clear(ibuf);
1150 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1151 		err = got_error_from_errno("close");
1152 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1153 		err = got_error_from_errno("close");
1154 	if (err == NULL && failed)
1155 		err = got_error(GOT_ERR_PATCH_FAILED);
1156 	return err;
1157 }