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