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 <errno.h>
30 #include <limits.h>
31 #include <sha1.h>
32 #include <stdint.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 #include <imsg.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_opentemp.h"
46 #include "got_patch.h"
47 
48 #include "got_lib_delta.h"
49 #include "got_lib_object.h"
50 #include "got_lib_privsep.h"
51 
52 #define MIN(a, b) ((a) < (b) ? (a) : (b))
53 
54 struct got_patch_hunk {
55 	STAILQ_ENTRY(got_patch_hunk) entries;
56 	const struct got_error *err;
57 	int	offset;
58 	int	old_nonl;
59 	int	new_nonl;
60 	int	old_from;
61 	int	old_lines;
62 	int	new_from;
63 	int	new_lines;
64 	size_t	len;
65 	size_t	cap;
66 	char	**lines;
67 };
68 
69 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
70 struct got_patch {
71 	char	*old;
72 	char	*new;
73 	struct got_patch_hunk_head head;
74 };
75 
76 struct patch_args {
77 	got_patch_progress_cb progress_cb;
78 	void	*progress_arg;
79 	struct got_patch_hunk_head *head;
80 };
81 
82 static const struct got_error *
83 send_patch(struct imsgbuf *ibuf, int fd)
84 {
85 	const struct got_error *err = NULL;
86 
87 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
88 	    NULL, 0) == -1) {
89 		err = got_error_from_errno(
90 		    "imsg_compose GOT_IMSG_PATCH_FILE");
91 		close(fd);
92 		return err;
93 	}
94 
95 	if (imsg_flush(ibuf) == -1) {
96 		err = got_error_from_errno("imsg_flush");
97 		imsg_clear(ibuf);
98 	}
99 
100 	return err;
101 }
102 
103 static void
104 patch_free(struct got_patch *p)
105 {
106 	struct got_patch_hunk *h;
107 	size_t i;
108 
109 	while (!STAILQ_EMPTY(&p->head)) {
110 		h = STAILQ_FIRST(&p->head);
111 		STAILQ_REMOVE_HEAD(&p->head, entries);
112 
113 		for (i = 0; i < h->len; ++i)
114 			free(h->lines[i]);
115 		free(h->lines);
116 		free(h);
117 	}
118 
119 	free(p->new);
120 	free(p->old);
121 
122 	memset(p, 0, sizeof(*p));
123 	STAILQ_INIT(&p->head);
124 }
125 
126 static const struct got_error *
127 pushline(struct got_patch_hunk *h, const char *line)
128 {
129 	void 	*t;
130 	size_t	 newcap;
131 
132 	if (h->len == h->cap) {
133 		if ((newcap = h->cap * 1.5) == 0)
134 			newcap = 16;
135 		t = recallocarray(h->lines, h->cap, newcap,
136 		    sizeof(h->lines[0]));
137 		if (t == NULL)
138 			return got_error_from_errno("recallocarray");
139 		h->lines = t;
140 		h->cap = newcap;
141 	}
142 
143 	if ((t = strdup(line)) == NULL)
144 		return got_error_from_errno("strdup");
145 
146 	h->lines[h->len++] = t;
147 	return NULL;
148 }
149 
150 static const struct got_error *
151 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
152 {
153 	const struct got_error *err = NULL;
154 	struct imsg imsg;
155 	struct got_imsg_patch_hunk hdr;
156 	struct got_imsg_patch patch;
157 	struct got_patch_hunk *h = NULL;
158 	size_t datalen;
159 	int lastmode = -1;
160 
161 	memset(p, 0, sizeof(*p));
162 	STAILQ_INIT(&p->head);
163 
164 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
165 	if (err)
166 		return err;
167 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
168 		*done = 1;
169 		goto done;
170 	}
171 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
172 		err = got_error(GOT_ERR_PRIVSEP_MSG);
173 		goto done;
174 	}
175 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
176 	if (datalen != sizeof(patch)) {
177 		err = got_error(GOT_ERR_PRIVSEP_LEN);
178 		goto done;
179 	}
180 	memcpy(&patch, imsg.data, sizeof(patch));
181 
182 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
183 	    patch.new[sizeof(patch.new)-1] != '\0') {
184 		err = got_error(GOT_ERR_PRIVSEP_LEN);
185 		goto done;
186 	}
187 
188 	/* automatically set strip=1 for git-style diffs */
189 	if (strip == -1 && patch.git &&
190 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
191 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
192 		strip = 1;
193 
194 	/* prefer the new name if not /dev/null for not git-style diffs */
195 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
196 		err = got_path_strip(&p->old, patch.new, strip);
197 		if (err)
198 			goto done;
199 	} else if (*patch.old != '\0') {
200 		err = got_path_strip(&p->old, patch.old, strip);
201 		if (err)
202 			goto done;
203 	}
204 
205 	if (*patch.new != '\0') {
206 		err = got_path_strip(&p->new, patch.new, strip);
207 		if (err)
208 			goto done;
209 	}
210 
211 	if (p->old == NULL && p->new == NULL) {
212 		err = got_error(GOT_ERR_PATCH_MALFORMED);
213 		goto done;
214 	}
215 
216 	imsg_free(&imsg);
217 
218 	for (;;) {
219 		char *t;
220 
221 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
222 		if (err) {
223 			patch_free(p);
224 			return err;
225 		}
226 
227 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
228 		switch (imsg.hdr.type) {
229 		case GOT_IMSG_PATCH_DONE:
230 			if (h != NULL && h->len == 0)
231 				err = got_error(GOT_ERR_PATCH_MALFORMED);
232 			goto done;
233 		case GOT_IMSG_PATCH_HUNK:
234 			if (h != NULL &&
235 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
236 				err = got_error(GOT_ERR_PATCH_MALFORMED);
237 				goto done;
238 			}
239 			lastmode = -1;
240 			if (datalen != sizeof(hdr)) {
241 				err = got_error(GOT_ERR_PRIVSEP_LEN);
242 				goto done;
243 			}
244 			memcpy(&hdr, imsg.data, sizeof(hdr));
245 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
246 				err = got_error(GOT_ERR_PRIVSEP_LEN);
247 				goto done;
248 			}
249 			if ((h = calloc(1, sizeof(*h))) == NULL) {
250 				err = got_error_from_errno("calloc");
251 				goto done;
252 			}
253 			h->old_from = hdr.oldfrom;
254 			h->old_lines = hdr.oldlines;
255 			h->new_from = hdr.newfrom;
256 			h->new_lines = hdr.newlines;
257 			STAILQ_INSERT_TAIL(&p->head, h, entries);
258 			break;
259 		case GOT_IMSG_PATCH_LINE:
260 			if (h == NULL) {
261 				err = got_error(GOT_ERR_PRIVSEP_MSG);
262 				goto done;
263 			}
264 			t = imsg.data;
265 			/* at least one char */
266 			if (datalen < 2 || t[datalen-1] != '\0') {
267 				err = got_error(GOT_ERR_PRIVSEP_MSG);
268 				goto done;
269 			}
270 			if (*t != ' ' && *t != '-' && *t != '+' &&
271 			    *t != '\\') {
272 				err = got_error(GOT_ERR_PRIVSEP_MSG);
273 				goto done;
274 			}
275 
276 			if (*t != '\\')
277 				err = pushline(h, t);
278 			else if (lastmode == '-')
279 				h->old_nonl = 1;
280 			else if (lastmode == '+')
281 				h->new_nonl = 1;
282 			else
283 				err = got_error(GOT_ERR_PATCH_MALFORMED);
284 
285 			if (err)
286 				goto done;
287 
288 			lastmode = *t;
289 			break;
290 		default:
291 			err = got_error(GOT_ERR_PRIVSEP_MSG);
292 			goto done;
293 		}
294 
295 		imsg_free(&imsg);
296 	}
297 
298 done:
299 	if (err)
300 		patch_free(p);
301 
302 	imsg_free(&imsg);
303 	return err;
304 }
305 
306 /*
307  * Copy data from orig starting at copypos until pos into tmp.
308  * If pos is -1, copy until EOF.
309  */
310 static const struct got_error *
311 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
312 {
313 	char buf[BUFSIZ];
314 	size_t len, r, w;
315 
316 	if (fseeko(orig, copypos, SEEK_SET) == -1)
317 		return got_error_from_errno("fseeko");
318 
319 	while (pos == -1 || copypos < pos) {
320 		len = sizeof(buf);
321 		if (pos > 0)
322 			len = MIN(len, (size_t)pos - copypos);
323 		r = fread(buf, 1, len, orig);
324 		if (r != len && ferror(orig))
325 			return got_error_from_errno("fread");
326 		w = fwrite(buf, 1, r, tmp);
327 		if (w != r)
328 			return got_error_from_errno("fwrite");
329 		copypos += len;
330 		if (r != len && feof(orig)) {
331 			if (pos == -1)
332 				return NULL;
333 			return got_error(GOT_ERR_HUNK_FAILED);
334 		}
335 	}
336 	return NULL;
337 }
338 
339 static const struct got_error *
340 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
341 {
342 	const struct got_error *err = NULL;
343 	char *line = NULL;
344 	char mode = *h->lines[0];
345 	size_t linesize = 0;
346 	ssize_t linelen;
347 	off_t match = -1;
348 	int match_lineno = -1;
349 
350 	for (;;) {
351 		linelen = getline(&line, &linesize, orig);
352 		if (linelen == -1) {
353 			if (ferror(orig))
354 				err = got_error_from_errno("getline");
355 			else if (match == -1)
356 				err = got_error(GOT_ERR_HUNK_FAILED);
357 			break;
358 		}
359 		if (line[linelen - 1] == '\n')
360 			line[linelen - 1] = '\0';
361 		(*lineno)++;
362 
363 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
364 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
365 		    (mode == '+' && *lineno == h->old_from)) {
366 			match = ftello(orig);
367 			if (match == -1) {
368 				err = got_error_from_errno("ftello");
369 				break;
370 			}
371 			match -= linelen;
372 			match_lineno = (*lineno)-1;
373 		}
374 
375 		if (*lineno >= h->old_from && match != -1)
376 			break;
377 	}
378 
379 	if (err == NULL) {
380 		*pos = match;
381 		*lineno = match_lineno;
382 		if (fseeko(orig, match, SEEK_SET) == -1)
383 			err = got_error_from_errno("fseeko");
384 	}
385 
386 	free(line);
387 	return err;
388 }
389 
390 static const struct got_error *
391 test_hunk(FILE *orig, struct got_patch_hunk *h)
392 {
393 	const struct got_error *err = NULL;
394 	char *line = NULL;
395 	size_t linesize = 0, i = 0;
396 	ssize_t linelen;
397 
398 	for (i = 0; i < h->len; ++i) {
399 		switch (*h->lines[i]) {
400 		case '+':
401 			continue;
402 		case ' ':
403 		case '-':
404 			linelen = getline(&line, &linesize, orig);
405 			if (linelen == -1) {
406 				if (ferror(orig))
407 					err = got_error_from_errno("getline");
408 				else
409 					err = got_error(
410 					    GOT_ERR_HUNK_FAILED);
411 				goto done;
412 			}
413 			if (line[linelen - 1] == '\n')
414 				line[linelen - 1] = '\0';
415 			if (strcmp(h->lines[i] + 1, line)) {
416 				err = got_error(GOT_ERR_HUNK_FAILED);
417 				goto done;
418 			}
419 			break;
420 		}
421 	}
422 
423 done:
424 	free(line);
425 	return err;
426 }
427 
428 static const struct got_error *
429 apply_hunk(FILE *tmp, struct got_patch_hunk *h, int *lineno)
430 {
431 	size_t i, new = 0;
432 
433 	for (i = 0; i < h->len; ++i) {
434 		switch (*h->lines[i]) {
435 		case ' ':
436 			if (fprintf(tmp, "%s\n", h->lines[i] + 1) < 0)
437 				return got_error_from_errno("fprintf");
438 			/* fallthrough */
439 		case '-':
440 			(*lineno)++;
441 			break;
442 		case '+':
443 			new++;
444 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0)
445 				return got_error_from_errno("fprintf");
446 			if (new != h->new_lines || !h->new_nonl) {
447 				if (fprintf(tmp, "\n") < 0)
448 					return got_error_from_errno(
449 					    "fprintf");
450 			}
451 			break;
452 		}
453 	}
454 	return NULL;
455 }
456 
457 static const struct got_error *
458 patch_file(struct got_patch *p, FILE *orig, FILE *tmp, int nop, mode_t *mode)
459 {
460 	const struct got_error *err = NULL;
461 	struct got_patch_hunk *h;
462 	struct stat sb;
463 	int lineno = 0;
464 	off_t copypos, pos;
465 	char *line = NULL;
466 	size_t linesize = 0;
467 	ssize_t linelen;
468 
469 	if (p->old == NULL) {				/* create */
470 		h = STAILQ_FIRST(&p->head);
471 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
472 			return got_error(GOT_ERR_PATCH_MALFORMED);
473 		if (nop)
474 			return NULL;
475 		return apply_hunk(tmp, h, &lineno);
476 	}
477 
478 	if (fstat(fileno(orig), &sb) == -1)
479 		return got_error_from_errno("fstat");
480 	*mode = sb.st_mode;
481 
482 	copypos = 0;
483 	STAILQ_FOREACH(h, &p->head, entries) {
484 	tryagain:
485 		err = locate_hunk(orig, h, &pos, &lineno);
486 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
487 			h->err = err;
488 		if (err != NULL)
489 			return err;
490 		if (!nop)
491 			err = copy(tmp, orig, copypos, pos);
492 		if (err != NULL)
493 			return err;
494 		copypos = pos;
495 
496 		err = test_hunk(orig, h);
497 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
498 			/*
499 			 * try to apply the hunk again starting the search
500 			 * after the previous partial match.
501 			 */
502 			if (fseeko(orig, pos, SEEK_SET) == -1)
503 				return got_error_from_errno("fseeko");
504 			linelen = getline(&line, &linesize, orig);
505 			if (linelen == -1)
506 				return got_error_from_errno("getline");
507 			lineno++;
508 			goto tryagain;
509 		}
510 		if (err != NULL)
511 			return err;
512 
513 		if (lineno + 1 != h->old_from)
514 			h->offset = lineno + 1 - h->old_from;
515 
516 		if (!nop)
517 			err = apply_hunk(tmp, h, &lineno);
518 		if (err != NULL)
519 			return err;
520 
521 		copypos = ftello(orig);
522 		if (copypos == -1)
523 			return got_error_from_errno("ftello");
524 	}
525 
526 	if (p->new == NULL && sb.st_size != copypos) {
527 		h = STAILQ_FIRST(&p->head);
528 		h->err = got_error(GOT_ERR_HUNK_FAILED);
529 		err = h->err;
530 	} else if (!nop && !feof(orig))
531 		err = copy(tmp, orig, copypos, -1);
532 
533 	return err;
534 }
535 
536 static const struct got_error *
537 report_progress(struct patch_args *pa, const char *old, const char *new,
538     unsigned char status, const struct got_error *orig_error)
539 {
540 	const struct got_error *err;
541 	struct got_patch_hunk *h;
542 
543 	err = pa->progress_cb(pa->progress_arg, old, new, status,
544 	    orig_error, 0, 0, 0, 0, 0, NULL);
545 	if (err)
546 		return err;
547 
548 	STAILQ_FOREACH(h, pa->head, entries) {
549 		if (h->offset == 0 && h->err == NULL)
550 			continue;
551 
552 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
553 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
554 		    h->offset, h->err);
555 		if (err)
556 			return err;
557 	}
558 
559 	return NULL;
560 }
561 
562 static const struct got_error *
563 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
564     const char *path)
565 {
566 	return report_progress(arg, path, NULL, status, NULL);
567 }
568 
569 static const struct got_error *
570 patch_add(void *arg, unsigned char status, const char *path)
571 {
572 	return report_progress(arg, NULL, path, status, NULL);
573 }
574 
575 static const struct got_error *
576 apply_patch(struct got_worktree *worktree, struct got_repository *repo,
577     struct got_fileindex *fileindex, const char *old, const char *new,
578     struct got_patch *p, int nop, struct patch_args *pa,
579     got_cancel_cb cancel_cb, void *cancel_arg)
580 {
581 	const struct got_error *err = NULL;
582 	int file_renamed = 0;
583 	char *oldpath = NULL, *newpath = NULL;
584 	char *tmppath = NULL, *template = NULL, *parent = NULL;
585 	FILE *oldfile = NULL, *tmp = NULL;
586 	mode_t mode = GOT_DEFAULT_FILE_MODE;
587 
588 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
589 	    old) == -1) {
590 		err = got_error_from_errno("asprintf");
591 		goto done;
592 	}
593 
594 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
595 	    new) == -1) {
596 		err = got_error_from_errno("asprintf");
597 		goto done;
598 	}
599 
600 	file_renamed = strcmp(oldpath, newpath);
601 
602 	if (asprintf(&template, "%s/got-patch",
603 	    got_worktree_get_root_path(worktree)) == -1) {
604 		err = got_error_from_errno(template);
605 		goto done;
606 	}
607 
608 	if (p->old != NULL && (oldfile = fopen(oldpath, "r")) == NULL) {
609 		err = got_error_from_errno2("open", oldpath);
610 		goto done;
611 	}
612 
613 	if (!nop)
614 		err = got_opentemp_named(&tmppath, &tmp, template);
615 	if (err)
616 		goto done;
617 	err = patch_file(p, oldfile, tmp, nop, &mode);
618 	if (err)
619 		goto done;
620 
621 	if (nop)
622 		goto done;
623 
624 	if (p->old != NULL && p->new == NULL) {
625 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
626 		    fileindex, patch_delete, pa);
627 		goto done;
628 	}
629 
630 	if (fchmod(fileno(tmp), mode) == -1) {
631 		err = got_error_from_errno2("chmod", tmppath);
632 		goto done;
633 	}
634 
635 	if (rename(tmppath, newpath) == -1) {
636 		if (errno != ENOENT) {
637 			err = got_error_from_errno3("rename", tmppath,
638 			    newpath);
639 			goto done;
640 		}
641 
642 		err = got_path_dirname(&parent, newpath);
643 		if (err != NULL)
644 			goto done;
645 		err = got_path_mkdir(parent);
646 		if (err != NULL)
647 			goto done;
648 		if (rename(tmppath, newpath) == -1) {
649 			err = got_error_from_errno3("rename", tmppath,
650 			    newpath);
651 			goto done;
652 		}
653 	}
654 
655 	if (file_renamed) {
656 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
657 		    fileindex, patch_delete, pa);
658 		if (err == NULL)
659 			err = got_worktree_patch_schedule_add(new, repo,
660 			    worktree, fileindex, patch_add,
661 			    pa);
662 		if (err)
663 			unlink(newpath);
664 	} else if (p->old == NULL) {
665 		err = got_worktree_patch_schedule_add(new, repo, worktree,
666 		    fileindex, patch_add, pa);
667 		if (err)
668 			unlink(newpath);
669 	} else
670 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
671 
672 done:
673 	free(parent);
674 	free(template);
675 	if (tmppath != NULL)
676 		unlink(tmppath);
677 	if (tmp != NULL && fclose(tmp) == EOF && err == NULL)
678 		err = got_error_from_errno("fclose");
679 	free(tmppath);
680 	free(oldpath);
681 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
682 		err = got_error_from_errno("fclose");
683 	free(newpath);
684 	return err;
685 }
686 
687 static void
688 reverse_patch(struct got_patch *p)
689 {
690 	struct got_patch_hunk *h;
691 	size_t i;
692 	int tmp;
693 
694 	STAILQ_FOREACH(h, &p->head, entries) {
695 		tmp = h->old_from;
696 		h->old_from = h->new_from;
697 		h->new_from = tmp;
698 
699 		tmp = h->old_lines;
700 		h->old_lines = h->new_lines;
701 		h->new_lines = tmp;
702 
703 		tmp = h->old_nonl;
704 		h->old_nonl = h->new_nonl;
705 		h->new_nonl = tmp;
706 
707 		for (i = 0; i < h->len; ++i) {
708 			if (*h->lines[i] == '+')
709 				*h->lines[i] = '-';
710 			else if (*h->lines[i] == '-')
711 				*h->lines[i] = '+';
712 		}
713 	}
714 }
715 
716 const struct got_error *
717 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
718     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
719     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
720 {
721 	const struct got_error *err = NULL, *complete_err = NULL;
722 	struct got_fileindex *fileindex = NULL;
723 	char *fileindex_path = NULL;
724 	char *oldpath, *newpath;
725 	struct imsgbuf *ibuf;
726 	int imsg_fds[2] = {-1, -1};
727 	int done = 0, failed = 0;
728 	pid_t pid;
729 
730 	ibuf = calloc(1, sizeof(*ibuf));
731 	if (ibuf == NULL) {
732 		err = got_error_from_errno("calloc");
733 		goto done;
734 	}
735 
736 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
737 		err = got_error_from_errno("socketpair");
738 		goto done;
739 	}
740 
741 	pid = fork();
742 	if (pid == -1) {
743 		err = got_error_from_errno("fork");
744 		goto done;
745 	} else if (pid == 0) {
746 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
747 		    NULL);
748 		/* not reached */
749 	}
750 
751 	if (close(imsg_fds[1]) == -1) {
752 		err = got_error_from_errno("close");
753 		goto done;
754 	}
755 	imsg_fds[1] = -1;
756 	imsg_init(ibuf, imsg_fds[0]);
757 
758 	err = send_patch(ibuf, fd);
759 	fd = -1;
760 	if (err)
761 		goto done;
762 
763 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
764 	    worktree);
765 	if (err)
766 		goto done;
767 
768 	while (!done && err == NULL) {
769 		struct got_patch p;
770 		struct patch_args pa;
771 
772 		pa.progress_cb = progress_cb;
773 		pa.progress_arg = progress_arg;
774 		pa.head = &p.head;
775 
776 		err = recv_patch(ibuf, &done, &p, strip);
777 		if (err || done)
778 			break;
779 
780 		if (reverse)
781 			reverse_patch(&p);
782 
783 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
784 		    &newpath, worktree, repo, fileindex);
785 		if (err == NULL)
786 			err = apply_patch(worktree, repo, fileindex, oldpath,
787 			    newpath, &p, nop, &pa, cancel_cb, cancel_arg);
788 		if (err != NULL) {
789 			failed = 1;
790 			/* recoverable errors */
791 			if (err->code == GOT_ERR_FILE_STATUS ||
792 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
793 				err = report_progress(&pa, p.old, p.new,
794 				    GOT_STATUS_CANNOT_UPDATE, err);
795 			else if (err->code == GOT_ERR_HUNK_FAILED)
796 				err = report_progress(&pa, p.old, p.new,
797 				    GOT_STATUS_CANNOT_UPDATE, NULL);
798 		}
799 
800 		free(oldpath);
801 		free(newpath);
802 		patch_free(&p);
803 
804 		if (err)
805 			break;
806 	}
807 
808 done:
809 	if (fileindex != NULL)
810 		complete_err = got_worktree_patch_complete(fileindex,
811 		    fileindex_path);
812 	if (complete_err && err == NULL)
813 		err = complete_err;
814 	free(fileindex_path);
815 	if (fd != -1 && close(fd) == -1 && err == NULL)
816 		err = got_error_from_errno("close");
817 	if (ibuf != NULL)
818 		imsg_clear(ibuf);
819 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
820 		err = got_error_from_errno("close");
821 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
822 		err = got_error_from_errno("close");
823 	if (err == NULL && failed)
824 		err = got_error(GOT_ERR_PATCH_FAILED);
825 	return err;
826 }