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/socket.h>
25 #include <sys/stat.h>
26 #include <sys/uio.h>
27 
28 #include <errno.h>
29 #include <limits.h>
30 #include <stdint.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_path.h"
39 #include "got_reference.h"
40 #include "got_cancel.h"
41 #include "got_worktree.h"
42 #include "got_opentemp.h"
43 #include "got_patch.h"
44 
45 #include "got_lib_delta.h"
46 #include "got_lib_object.h"
47 #include "got_lib_privsep.h"
48 
49 #define MIN(a, b) ((a) < (b) ? (a) : (b))
50 
51 struct got_patch_hunk {
52 	STAILQ_ENTRY(got_patch_hunk) entries;
53 	const struct got_error *err;
54 	int	offset;
55 	int	old_nonl;
56 	int	new_nonl;
57 	int	old_from;
58 	int	old_lines;
59 	int	new_from;
60 	int	new_lines;
61 	size_t	len;
62 	size_t	cap;
63 	char	**lines;
64 };
65 
66 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
67 struct got_patch {
68 	char	*old;
69 	char	*new;
70 	struct got_patch_hunk_head head;
71 };
72 
73 struct patch_args {
74 	got_patch_progress_cb progress_cb;
75 	void	*progress_arg;
76 	struct got_patch_hunk_head *head;
77 };
78 
79 static const struct got_error *
80 send_patch(struct imsgbuf *ibuf, int fd)
81 {
82 	const struct got_error *err = NULL;
83 
84 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
85 	    NULL, 0) == -1) {
86 		err = got_error_from_errno(
87 		    "imsg_compose GOT_IMSG_PATCH_FILE");
88 		close(fd);
89 		return err;
90 	}
91 
92 	if (imsg_flush(ibuf) == -1) {
93 		err = got_error_from_errno("imsg_flush");
94 		imsg_clear(ibuf);
95 	}
96 
97 	return err;
98 }
99 
100 static void
101 patch_free(struct got_patch *p)
102 {
103 	struct got_patch_hunk *h;
104 	size_t i;
105 
106 	while (!STAILQ_EMPTY(&p->head)) {
107 		h = STAILQ_FIRST(&p->head);
108 		STAILQ_REMOVE_HEAD(&p->head, entries);
109 
110 		for (i = 0; i < h->len; ++i)
111 			free(h->lines[i]);
112 		free(h->lines);
113 		free(h);
114 	}
115 
116 	free(p->new);
117 	free(p->old);
118 
119 	memset(p, 0, sizeof(*p));
120 	STAILQ_INIT(&p->head);
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 			patch_free(p);
221 			return err;
222 		}
223 
224 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
225 		switch (imsg.hdr.type) {
226 		case GOT_IMSG_PATCH_DONE:
227 			if (h != NULL && h->len == 0)
228 				err = got_error(GOT_ERR_PATCH_MALFORMED);
229 			goto done;
230 		case GOT_IMSG_PATCH_HUNK:
231 			if (h != NULL &&
232 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
233 				err = got_error(GOT_ERR_PATCH_MALFORMED);
234 				goto done;
235 			}
236 			lastmode = -1;
237 			if (datalen != sizeof(hdr)) {
238 				err = got_error(GOT_ERR_PRIVSEP_LEN);
239 				goto done;
240 			}
241 			memcpy(&hdr, imsg.data, sizeof(hdr));
242 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
243 				err = got_error(GOT_ERR_PRIVSEP_LEN);
244 				goto done;
245 			}
246 			if ((h = calloc(1, sizeof(*h))) == NULL) {
247 				err = got_error_from_errno("calloc");
248 				goto done;
249 			}
250 			h->old_from = hdr.oldfrom;
251 			h->old_lines = hdr.oldlines;
252 			h->new_from = hdr.newfrom;
253 			h->new_lines = hdr.newlines;
254 			STAILQ_INSERT_TAIL(&p->head, h, entries);
255 			break;
256 		case GOT_IMSG_PATCH_LINE:
257 			if (h == NULL) {
258 				err = got_error(GOT_ERR_PRIVSEP_MSG);
259 				goto done;
260 			}
261 			t = imsg.data;
262 			/* at least one char */
263 			if (datalen < 2 || t[datalen-1] != '\0') {
264 				err = got_error(GOT_ERR_PRIVSEP_MSG);
265 				goto done;
266 			}
267 			if (*t != ' ' && *t != '-' && *t != '+' &&
268 			    *t != '\\') {
269 				err = got_error(GOT_ERR_PRIVSEP_MSG);
270 				goto done;
271 			}
272 
273 			if (*t != '\\')
274 				err = pushline(h, t);
275 			else if (lastmode == '-')
276 				h->old_nonl = 1;
277 			else if (lastmode == '+')
278 				h->new_nonl = 1;
279 			else
280 				err = got_error(GOT_ERR_PATCH_MALFORMED);
281 
282 			if (err)
283 				goto done;
284 
285 			lastmode = *t;
286 			break;
287 		default:
288 			err = got_error(GOT_ERR_PRIVSEP_MSG);
289 			goto done;
290 		}
291 
292 		imsg_free(&imsg);
293 	}
294 
295 done:
296 	if (err)
297 		patch_free(p);
298 
299 	imsg_free(&imsg);
300 	return err;
301 }
302 
303 /*
304  * Copy data from orig starting at copypos until pos into tmp.
305  * If pos is -1, copy until EOF.
306  */
307 static const struct got_error *
308 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
309 {
310 	char buf[BUFSIZ];
311 	size_t len, r, w;
312 
313 	if (fseeko(orig, copypos, SEEK_SET) == -1)
314 		return got_error_from_errno("fseeko");
315 
316 	while (pos == -1 || copypos < pos) {
317 		len = sizeof(buf);
318 		if (pos > 0)
319 			len = MIN(len, (size_t)pos - copypos);
320 		r = fread(buf, 1, len, orig);
321 		if (r != len && ferror(orig))
322 			return got_error_from_errno("fread");
323 		w = fwrite(buf, 1, r, tmp);
324 		if (w != r)
325 			return got_error_from_errno("fwrite");
326 		copypos += len;
327 		if (r != len && feof(orig)) {
328 			if (pos == -1)
329 				return NULL;
330 			return got_error(GOT_ERR_HUNK_FAILED);
331 		}
332 	}
333 	return NULL;
334 }
335 
336 static const struct got_error *
337 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
338 {
339 	const struct got_error *err = NULL;
340 	char *line = NULL;
341 	char mode = *h->lines[0];
342 	size_t linesize = 0;
343 	ssize_t linelen;
344 	off_t match = -1;
345 	int match_lineno = -1;
346 
347 	for (;;) {
348 		linelen = getline(&line, &linesize, orig);
349 		if (linelen == -1) {
350 			if (ferror(orig))
351 				err = got_error_from_errno("getline");
352 			else if (match == -1)
353 				err = got_error(GOT_ERR_HUNK_FAILED);
354 			break;
355 		}
356 		if (line[linelen - 1] == '\n')
357 			line[linelen - 1] = '\0';
358 		(*lineno)++;
359 
360 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
361 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
362 		    (mode == '+' && *lineno == h->old_from)) {
363 			match = ftello(orig);
364 			if (match == -1) {
365 				err = got_error_from_errno("ftello");
366 				break;
367 			}
368 			match -= linelen;
369 			match_lineno = (*lineno)-1;
370 		}
371 
372 		if (*lineno >= h->old_from && match != -1)
373 			break;
374 	}
375 
376 	if (err == NULL) {
377 		*pos = match;
378 		*lineno = match_lineno;
379 		if (fseeko(orig, match, SEEK_SET) == -1)
380 			err = got_error_from_errno("fseeko");
381 	}
382 
383 	free(line);
384 	return err;
385 }
386 
387 static const struct got_error *
388 test_hunk(FILE *orig, struct got_patch_hunk *h)
389 {
390 	const struct got_error *err = NULL;
391 	char *line = NULL;
392 	size_t linesize = 0, i = 0;
393 	ssize_t linelen;
394 
395 	for (i = 0; i < h->len; ++i) {
396 		switch (*h->lines[i]) {
397 		case '+':
398 			continue;
399 		case ' ':
400 		case '-':
401 			linelen = getline(&line, &linesize, orig);
402 			if (linelen == -1) {
403 				if (ferror(orig))
404 					err = got_error_from_errno("getline");
405 				else
406 					err = got_error(
407 					    GOT_ERR_HUNK_FAILED);
408 				goto done;
409 			}
410 			if (line[linelen - 1] == '\n')
411 				line[linelen - 1] = '\0';
412 			if (strcmp(h->lines[i] + 1, line)) {
413 				err = got_error(GOT_ERR_HUNK_FAILED);
414 				goto done;
415 			}
416 			break;
417 		}
418 	}
419 
420 done:
421 	free(line);
422 	return err;
423 }
424 
425 static const struct got_error *
426 apply_hunk(FILE *tmp, struct got_patch_hunk *h, int *lineno)
427 {
428 	size_t i, new = 0;
429 
430 	for (i = 0; i < h->len; ++i) {
431 		switch (*h->lines[i]) {
432 		case ' ':
433 			if (fprintf(tmp, "%s\n", h->lines[i] + 1) < 0)
434 				return got_error_from_errno("fprintf");
435 			/* fallthrough */
436 		case '-':
437 			(*lineno)++;
438 			break;
439 		case '+':
440 			new++;
441 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0)
442 				return got_error_from_errno("fprintf");
443 			if (new != h->new_lines || !h->new_nonl) {
444 				if (fprintf(tmp, "\n") < 0)
445 					return got_error_from_errno(
446 					    "fprintf");
447 			}
448 			break;
449 		}
450 	}
451 	return NULL;
452 }
453 
454 static const struct got_error *
455 patch_file(struct got_patch *p, const char *path, FILE *tmp, int nop,
456     mode_t *mode)
457 {
458 	const struct got_error *err = NULL;
459 	struct got_patch_hunk *h;
460 	struct stat sb;
461 	int lineno = 0;
462 	FILE *orig;
463 	off_t copypos, pos;
464 	char *line = NULL;
465 	size_t linesize = 0;
466 	ssize_t linelen;
467 
468 	if (p->old == NULL) {				/* create */
469 		h = STAILQ_FIRST(&p->head);
470 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
471 			return got_error(GOT_ERR_PATCH_MALFORMED);
472 		if (nop)
473 			return NULL;
474 		return apply_hunk(tmp, h, &lineno);
475 	}
476 
477 	if ((orig = fopen(path, "r")) == NULL) {
478 		err = got_error_from_errno2("fopen", path);
479 		goto done;
480 	}
481 
482 	if (fstat(fileno(orig), &sb) == -1) {
483 		err = got_error_from_errno("fstat");
484 		goto done;
485 	}
486 	*mode = sb.st_mode;
487 
488 	copypos = 0;
489 	STAILQ_FOREACH(h, &p->head, entries) {
490 	tryagain:
491 		err = locate_hunk(orig, h, &pos, &lineno);
492 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
493 			h->err = err;
494 		if (err != NULL)
495 			goto done;
496 		if (!nop)
497 			err = copy(tmp, orig, copypos, pos);
498 		if (err != NULL)
499 			goto done;
500 		copypos = pos;
501 
502 		err = test_hunk(orig, h);
503 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
504 			/*
505 			 * try to apply the hunk again starting the search
506 			 * after the previous partial match.
507 			 */
508 			if (fseeko(orig, pos, SEEK_SET) == -1) {
509 				err = got_error_from_errno("fseeko");
510 				goto done;
511 			}
512 			linelen = getline(&line, &linesize, orig);
513 			if (linelen == -1) {
514 				err = got_error_from_errno("getline");
515 				goto done;
516 			}
517 			lineno++;
518 			goto tryagain;
519 		}
520 		if (err != NULL)
521 			goto done;
522 
523 		if (lineno + 1 != h->old_from)
524 			h->offset = lineno + 1 - h->old_from;
525 
526 		if (!nop)
527 			err = apply_hunk(tmp, h, &lineno);
528 		if (err != NULL)
529 			goto done;
530 
531 		copypos = ftello(orig);
532 		if (copypos == -1) {
533 			err = got_error_from_errno("ftello");
534 			goto done;
535 		}
536 	}
537 
538 	if (p->new == NULL && sb.st_size != copypos) {
539 		h = STAILQ_FIRST(&p->head);
540 		h->err = got_error(GOT_ERR_HUNK_FAILED);
541 		err = h->err;
542 	} else if (!nop && !feof(orig))
543 		err = copy(tmp, orig, copypos, -1);
544 
545 done:
546 	if (orig != NULL && fclose(orig) == EOF && err == NULL)
547 		err = got_error_from_errno("fclose");
548 	return err;
549 }
550 
551 static const struct got_error *
552 report_progress(struct patch_args *pa, const char *old, const char *new,
553     unsigned char status, const struct got_error *orig_error)
554 {
555 	const struct got_error *err;
556 	struct got_patch_hunk *h;
557 
558 	err = pa->progress_cb(pa->progress_arg, old, new, status,
559 	    orig_error, 0, 0, 0, 0, 0, NULL);
560 	if (err)
561 		return err;
562 
563 	STAILQ_FOREACH(h, pa->head, entries) {
564 		if (h->offset == 0 && h->err == NULL)
565 			continue;
566 
567 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
568 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
569 		    h->offset, h->err);
570 		if (err)
571 			return err;
572 	}
573 
574 	return NULL;
575 }
576 
577 static const struct got_error *
578 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
579     const char *path)
580 {
581 	return report_progress(arg, path, NULL, status, NULL);
582 }
583 
584 static const struct got_error *
585 patch_add(void *arg, unsigned char status, const char *path)
586 {
587 	return report_progress(arg, NULL, path, status, NULL);
588 }
589 
590 static const struct got_error *
591 apply_patch(struct got_worktree *worktree, struct got_repository *repo,
592     struct got_fileindex *fileindex, const char *old, const char *new,
593     struct got_patch *p, int nop, struct patch_args *pa,
594     got_cancel_cb cancel_cb, void *cancel_arg)
595 {
596 	const struct got_error *err = NULL;
597 	int file_renamed = 0;
598 	char *oldpath = NULL, *newpath = NULL;
599 	char *tmppath = NULL, *template = NULL, *parent = NULL;;
600 	FILE *tmp = NULL;
601 	mode_t mode = GOT_DEFAULT_FILE_MODE;
602 
603 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
604 	    old) == -1) {
605 		err = got_error_from_errno("asprintf");
606 		goto done;
607 	}
608 
609 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
610 	    new) == -1) {
611 		err = got_error_from_errno("asprintf");
612 		goto done;
613 	}
614 
615 	file_renamed = strcmp(oldpath, newpath);
616 
617 	if (asprintf(&template, "%s/got-patch",
618 	    got_worktree_get_root_path(worktree)) == -1) {
619 		err = got_error_from_errno(template);
620 		goto done;
621 	}
622 
623 	if (!nop)
624 		err = got_opentemp_named(&tmppath, &tmp, template);
625 	if (err)
626 		goto done;
627 	err = patch_file(p, oldpath, tmp, nop, &mode);
628 	if (err)
629 		goto done;
630 
631 	if (nop)
632 		goto done;
633 
634 	if (p->old != NULL && p->new == NULL) {
635 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
636 		    fileindex, patch_delete, pa);
637 		goto done;
638 	}
639 
640 	if (fchmod(fileno(tmp), mode) == -1) {
641 		err = got_error_from_errno2("chmod", tmppath);
642 		goto done;
643 	}
644 
645 	if (rename(tmppath, newpath) == -1) {
646 		if (errno != ENOENT) {
647 			err = got_error_from_errno3("rename", tmppath,
648 			    newpath);
649 			goto done;
650 		}
651 
652 		err = got_path_dirname(&parent, newpath);
653 		if (err != NULL)
654 			goto done;
655 		err = got_path_mkdir(parent);
656 		if (err != NULL)
657 			goto done;
658 		if (rename(tmppath, newpath) == -1) {
659 			err = got_error_from_errno3("rename", tmppath,
660 			    newpath);
661 			goto done;
662 		}
663 	}
664 
665 	if (file_renamed) {
666 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
667 		    fileindex, patch_delete, pa);
668 		if (err == NULL)
669 			err = got_worktree_patch_schedule_add(new, repo,
670 			    worktree, fileindex, patch_add,
671 			    pa);
672 		if (err)
673 			unlink(newpath);
674 	} else if (p->old == NULL) {
675 		err = got_worktree_patch_schedule_add(new, repo, worktree,
676 		    fileindex, patch_add, pa);
677 		if (err)
678 			unlink(newpath);
679 	} else
680 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
681 
682 done:
683 	free(parent);
684 	free(template);
685 	if (tmppath != NULL)
686 		unlink(tmppath);
687 	if (tmp != NULL && fclose(tmp) == EOF && err == NULL)
688 		err = got_error_from_errno("fclose");
689 	free(tmppath);
690 	free(oldpath);
691 	free(newpath);
692 	return err;
693 }
694 
695 static void
696 reverse_patch(struct got_patch *p)
697 {
698 	struct got_patch_hunk *h;
699 	size_t i;
700 	int tmp;
701 
702 	STAILQ_FOREACH(h, &p->head, entries) {
703 		tmp = h->old_from;
704 		h->old_from = h->new_from;
705 		h->new_from = tmp;
706 
707 		tmp = h->old_lines;
708 		h->old_lines = h->new_lines;
709 		h->new_lines = tmp;
710 
711 		tmp = h->old_nonl;
712 		h->old_nonl = h->new_nonl;
713 		h->new_nonl = tmp;
714 
715 		for (i = 0; i < h->len; ++i) {
716 			if (*h->lines[i] == '+')
717 				*h->lines[i] = '-';
718 			else if (*h->lines[i] == '-')
719 				*h->lines[i] = '+';
720 		}
721 	}
722 }
723 
724 const struct got_error *
725 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
726     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
727     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
728 {
729 	const struct got_error *err = NULL, *complete_err = NULL;
730 	struct got_fileindex *fileindex = NULL;
731 	char *fileindex_path = NULL;
732 	char *oldpath, *newpath;
733 	struct imsgbuf *ibuf;
734 	int imsg_fds[2] = {-1, -1};
735 	int done = 0, failed = 0;
736 	pid_t pid;
737 
738 	ibuf = calloc(1, sizeof(*ibuf));
739 	if (ibuf == NULL) {
740 		err = got_error_from_errno("calloc");
741 		goto done;
742 	}
743 
744 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
745 		err = got_error_from_errno("socketpair");
746 		goto done;
747 	}
748 
749 	pid = fork();
750 	if (pid == -1) {
751 		err = got_error_from_errno("fork");
752 		goto done;
753 	} else if (pid == 0) {
754 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
755 		    NULL);
756 		/* not reached */
757 	}
758 
759 	if (close(imsg_fds[1]) == -1) {
760 		err = got_error_from_errno("close");
761 		goto done;
762 	}
763 	imsg_fds[1] = -1;
764 	imsg_init(ibuf, imsg_fds[0]);
765 
766 	err = send_patch(ibuf, fd);
767 	fd = -1;
768 	if (err)
769 		goto done;
770 
771 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
772 	    worktree);
773 	if (err)
774 		goto done;
775 
776 	while (!done && err == NULL) {
777 		struct got_patch p;
778 		struct patch_args pa;
779 
780 		pa.progress_cb = progress_cb;
781 		pa.progress_arg = progress_arg;
782 		pa.head = &p.head;
783 
784 		err = recv_patch(ibuf, &done, &p, strip);
785 		if (err || done)
786 			break;
787 
788 		if (reverse)
789 			reverse_patch(&p);
790 
791 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
792 		    &newpath, worktree, repo, fileindex);
793 		if (err == NULL)
794 			err = apply_patch(worktree, repo, fileindex, oldpath,
795 			    newpath, &p, nop, &pa, cancel_cb, cancel_arg);
796 		if (err != NULL) {
797 			failed = 1;
798 			/* recoverable errors */
799 			if (err->code == GOT_ERR_FILE_STATUS ||
800 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
801 				err = report_progress(&pa, p.old, p.new,
802 				    GOT_STATUS_CANNOT_UPDATE, err);
803 			else if (err->code == GOT_ERR_HUNK_FAILED)
804 				err = report_progress(&pa, p.old, p.new,
805 				    GOT_STATUS_CANNOT_UPDATE, NULL);
806 		}
807 
808 		free(oldpath);
809 		free(newpath);
810 		patch_free(&p);
811 
812 		if (err)
813 			break;
814 	}
815 
816 done:
817 	if (fileindex != NULL)
818 		complete_err = got_worktree_patch_complete(fileindex,
819 		    fileindex_path);
820 	if (complete_err && err == NULL)
821 		err = complete_err;
822 	free(fileindex_path);
823 	if (fd != -1 && close(fd) == -1 && err == NULL)
824 		err = got_error_from_errno("close");
825 	if (ibuf != NULL)
826 		imsg_clear(ibuf);
827 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
828 		err = got_error_from_errno("close");
829 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
830 		err = got_error_from_errno("close");
831 	if (err == NULL && failed)
832 		err = got_error(GOT_ERR_PATCH_FAILED);
833 	return err;
834 }