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, 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 		return apply_hunk(tmp, h, &lineno);
474 	}
475 
476 	if (fstat(fileno(orig), &sb) == -1)
477 		return got_error_from_errno("fstat");
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 			return err;
488 		err = copy(tmp, orig, copypos, pos);
489 		if (err != NULL)
490 			return err;
491 		copypos = pos;
492 
493 		err = test_hunk(orig, h);
494 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
495 			/*
496 			 * try to apply the hunk again starting the search
497 			 * after the previous partial match.
498 			 */
499 			if (fseeko(orig, pos, SEEK_SET) == -1)
500 				return got_error_from_errno("fseeko");
501 			linelen = getline(&line, &linesize, orig);
502 			if (linelen == -1)
503 				return got_error_from_errno("getline");
504 			lineno++;
505 			goto tryagain;
506 		}
507 		if (err != NULL)
508 			return err;
509 
510 		if (lineno + 1 != h->old_from)
511 			h->offset = lineno + 1 - h->old_from;
512 
513 		err = apply_hunk(tmp, h, &lineno);
514 		if (err != NULL)
515 			return err;
516 
517 		copypos = ftello(orig);
518 		if (copypos == -1)
519 			return got_error_from_errno("ftello");
520 	}
521 
522 	if (p->new == NULL && sb.st_size != copypos) {
523 		h = STAILQ_FIRST(&p->head);
524 		h->err = got_error(GOT_ERR_HUNK_FAILED);
525 		err = h->err;
526 	} else if (!feof(orig))
527 		err = copy(tmp, orig, copypos, -1);
528 
529 	return err;
530 }
531 
532 static const struct got_error *
533 report_progress(struct patch_args *pa, const char *old, const char *new,
534     unsigned char status, const struct got_error *orig_error)
535 {
536 	const struct got_error *err;
537 	struct got_patch_hunk *h;
538 
539 	err = pa->progress_cb(pa->progress_arg, old, new, status,
540 	    orig_error, 0, 0, 0, 0, 0, NULL);
541 	if (err)
542 		return err;
543 
544 	STAILQ_FOREACH(h, pa->head, entries) {
545 		if (h->offset == 0 && h->err == NULL)
546 			continue;
547 
548 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
549 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
550 		    h->offset, h->err);
551 		if (err)
552 			return err;
553 	}
554 
555 	return NULL;
556 }
557 
558 static const struct got_error *
559 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
560     const char *path)
561 {
562 	return report_progress(arg, path, NULL, status, NULL);
563 }
564 
565 static const struct got_error *
566 patch_add(void *arg, unsigned char status, const char *path)
567 {
568 	return report_progress(arg, NULL, path, status, NULL);
569 }
570 
571 static const struct got_error *
572 apply_patch(struct got_worktree *worktree, struct got_repository *repo,
573     struct got_fileindex *fileindex, const char *old, const char *new,
574     struct got_patch *p, int nop, struct patch_args *pa,
575     got_cancel_cb cancel_cb, void *cancel_arg)
576 {
577 	const struct got_error *err = NULL;
578 	int file_renamed = 0;
579 	char *oldpath = NULL, *newpath = NULL;
580 	char *tmppath = NULL, *template = NULL, *parent = NULL;
581 	FILE *oldfile = NULL, *tmp = NULL;
582 	mode_t mode = GOT_DEFAULT_FILE_MODE;
583 
584 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
585 	    old) == -1) {
586 		err = got_error_from_errno("asprintf");
587 		goto done;
588 	}
589 
590 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
591 	    new) == -1) {
592 		err = got_error_from_errno("asprintf");
593 		goto done;
594 	}
595 
596 	file_renamed = strcmp(oldpath, newpath);
597 
598 	if (asprintf(&template, "%s/got-patch",
599 	    got_worktree_get_root_path(worktree)) == -1) {
600 		err = got_error_from_errno(template);
601 		goto done;
602 	}
603 
604 	if (p->old != NULL && (oldfile = fopen(oldpath, "r")) == NULL) {
605 		err = got_error_from_errno2("open", oldpath);
606 		goto done;
607 	}
608 
609 	err = got_opentemp_named(&tmppath, &tmp, template);
610 	if (err)
611 		goto done;
612 	err = patch_file(p, oldfile, tmp, &mode);
613 	if (err)
614 		goto done;
615 
616 	if (nop)
617 		goto done;
618 
619 	if (p->old != NULL && p->new == NULL) {
620 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
621 		    fileindex, patch_delete, pa);
622 		goto done;
623 	}
624 
625 	if (fchmod(fileno(tmp), mode) == -1) {
626 		err = got_error_from_errno2("chmod", tmppath);
627 		goto done;
628 	}
629 
630 	if (rename(tmppath, newpath) == -1) {
631 		if (errno != ENOENT) {
632 			err = got_error_from_errno3("rename", tmppath,
633 			    newpath);
634 			goto done;
635 		}
636 
637 		err = got_path_dirname(&parent, newpath);
638 		if (err != NULL)
639 			goto done;
640 		err = got_path_mkdir(parent);
641 		if (err != NULL)
642 			goto done;
643 		if (rename(tmppath, newpath) == -1) {
644 			err = got_error_from_errno3("rename", tmppath,
645 			    newpath);
646 			goto done;
647 		}
648 	}
649 
650 	if (file_renamed) {
651 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
652 		    fileindex, patch_delete, pa);
653 		if (err == NULL)
654 			err = got_worktree_patch_schedule_add(new, repo,
655 			    worktree, fileindex, patch_add,
656 			    pa);
657 		if (err)
658 			unlink(newpath);
659 	} else if (p->old == NULL) {
660 		err = got_worktree_patch_schedule_add(new, repo, worktree,
661 		    fileindex, patch_add, pa);
662 		if (err)
663 			unlink(newpath);
664 	} else
665 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
666 
667 done:
668 	free(parent);
669 	free(template);
670 	if (tmppath != NULL)
671 		unlink(tmppath);
672 	if (tmp != NULL && fclose(tmp) == EOF && err == NULL)
673 		err = got_error_from_errno("fclose");
674 	free(tmppath);
675 	free(oldpath);
676 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
677 		err = got_error_from_errno("fclose");
678 	free(newpath);
679 	return err;
680 }
681 
682 static void
683 reverse_patch(struct got_patch *p)
684 {
685 	struct got_patch_hunk *h;
686 	size_t i;
687 	int tmp;
688 
689 	STAILQ_FOREACH(h, &p->head, entries) {
690 		tmp = h->old_from;
691 		h->old_from = h->new_from;
692 		h->new_from = tmp;
693 
694 		tmp = h->old_lines;
695 		h->old_lines = h->new_lines;
696 		h->new_lines = tmp;
697 
698 		tmp = h->old_nonl;
699 		h->old_nonl = h->new_nonl;
700 		h->new_nonl = tmp;
701 
702 		for (i = 0; i < h->len; ++i) {
703 			if (*h->lines[i] == '+')
704 				*h->lines[i] = '-';
705 			else if (*h->lines[i] == '-')
706 				*h->lines[i] = '+';
707 		}
708 	}
709 }
710 
711 const struct got_error *
712 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
713     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
714     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
715 {
716 	const struct got_error *err = NULL, *complete_err = NULL;
717 	struct got_fileindex *fileindex = NULL;
718 	char *fileindex_path = NULL;
719 	char *oldpath, *newpath;
720 	struct imsgbuf *ibuf;
721 	int imsg_fds[2] = {-1, -1};
722 	int done = 0, failed = 0;
723 	pid_t pid;
724 
725 	ibuf = calloc(1, sizeof(*ibuf));
726 	if (ibuf == NULL) {
727 		err = got_error_from_errno("calloc");
728 		goto done;
729 	}
730 
731 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
732 		err = got_error_from_errno("socketpair");
733 		goto done;
734 	}
735 
736 	pid = fork();
737 	if (pid == -1) {
738 		err = got_error_from_errno("fork");
739 		goto done;
740 	} else if (pid == 0) {
741 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
742 		    NULL);
743 		/* not reached */
744 	}
745 
746 	if (close(imsg_fds[1]) == -1) {
747 		err = got_error_from_errno("close");
748 		goto done;
749 	}
750 	imsg_fds[1] = -1;
751 	imsg_init(ibuf, imsg_fds[0]);
752 
753 	err = send_patch(ibuf, fd);
754 	fd = -1;
755 	if (err)
756 		goto done;
757 
758 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
759 	    worktree);
760 	if (err)
761 		goto done;
762 
763 	while (!done && err == NULL) {
764 		struct got_patch p;
765 		struct patch_args pa;
766 
767 		pa.progress_cb = progress_cb;
768 		pa.progress_arg = progress_arg;
769 		pa.head = &p.head;
770 
771 		err = recv_patch(ibuf, &done, &p, strip);
772 		if (err || done)
773 			break;
774 
775 		if (reverse)
776 			reverse_patch(&p);
777 
778 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
779 		    &newpath, worktree, repo, fileindex);
780 		if (err == NULL)
781 			err = apply_patch(worktree, repo, fileindex, oldpath,
782 			    newpath, &p, nop, &pa, cancel_cb, cancel_arg);
783 		if (err != NULL) {
784 			failed = 1;
785 			/* recoverable errors */
786 			if (err->code == GOT_ERR_FILE_STATUS ||
787 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
788 				err = report_progress(&pa, p.old, p.new,
789 				    GOT_STATUS_CANNOT_UPDATE, err);
790 			else if (err->code == GOT_ERR_HUNK_FAILED)
791 				err = report_progress(&pa, p.old, p.new,
792 				    GOT_STATUS_CANNOT_UPDATE, NULL);
793 		}
794 
795 		free(oldpath);
796 		free(newpath);
797 		patch_free(&p);
798 
799 		if (err)
800 			break;
801 	}
802 
803 done:
804 	if (fileindex != NULL)
805 		complete_err = got_worktree_patch_complete(fileindex,
806 		    fileindex_path);
807 	if (complete_err && err == NULL)
808 		err = complete_err;
809 	free(fileindex_path);
810 	if (fd != -1 && close(fd) == -1 && err == NULL)
811 		err = got_error_from_errno("close");
812 	if (ibuf != NULL)
813 		imsg_clear(ibuf);
814 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
815 		err = got_error_from_errno("close");
816 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
817 		err = got_error_from_errno("close");
818 	if (err == NULL && failed)
819 		err = got_error(GOT_ERR_PATCH_FAILED);
820 	return err;
821 }