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Date:: Tue Jun 28 13:27:12 2022 UTC
Message:: move got_opentempfd out of open_blob. ok stsp@
Actions:: History | Blame | Raw File
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_repository.h"
46 #include "got_opentemp.h"
47 #include "got_patch.h"
48 
49 #include "got_lib_delta.h"
50 #include "got_lib_diff.h"
51 #include "got_lib_object.h"
52 #include "got_lib_privsep.h"
53 #include "got_lib_sha1.h"
54 
55 #define MIN(a, b) ((a) < (b) ? (a) : (b))
56 
57 struct got_patch_hunk {
58 	STAILQ_ENTRY(got_patch_hunk) entries;
59 	const struct got_error *err;
60 	int	offset;
61 	int	old_nonl;
62 	int	new_nonl;
63 	int	old_from;
64 	int	old_lines;
65 	int	new_from;
66 	int	new_lines;
67 	size_t	len;
68 	size_t	cap;
69 	char	**lines;
70 };
71 
72 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
73 struct got_patch {
74 	char	*old;
75 	char	*new;
76 	char	 cid[41];
77 	char	 blob[41];
78 	struct got_patch_hunk_head head;
79 };
80 
81 struct patch_args {
82 	got_patch_progress_cb progress_cb;
83 	void	*progress_arg;
84 	struct got_patch_hunk_head *head;
85 };
86 
87 static const struct got_error *
88 send_patch(struct imsgbuf *ibuf, int fd)
89 {
90 	const struct got_error *err = NULL;
91 
92 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
93 	    NULL, 0) == -1) {
94 		err = got_error_from_errno(
95 		    "imsg_compose GOT_IMSG_PATCH_FILE");
96 		close(fd);
97 		return err;
98 	}
99 
100 	if (imsg_flush(ibuf) == -1) {
101 		err = got_error_from_errno("imsg_flush");
102 		imsg_clear(ibuf);
103 	}
104 
105 	return err;
106 }
107 
108 static void
109 patch_free(struct got_patch *p)
110 {
111 	struct got_patch_hunk *h;
112 	size_t i;
113 
114 	while (!STAILQ_EMPTY(&p->head)) {
115 		h = STAILQ_FIRST(&p->head);
116 		STAILQ_REMOVE_HEAD(&p->head, entries);
117 
118 		for (i = 0; i < h->len; ++i)
119 			free(h->lines[i]);
120 		free(h->lines);
121 		free(h);
122 	}
123 
124 	free(p->new);
125 	free(p->old);
126 
127 	memset(p, 0, sizeof(*p));
128 	STAILQ_INIT(&p->head);
129 }
130 
131 static const struct got_error *
132 pushline(struct got_patch_hunk *h, const char *line)
133 {
134 	void 	*t;
135 	size_t	 newcap;
136 
137 	if (h->len == h->cap) {
138 		if ((newcap = h->cap * 1.5) == 0)
139 			newcap = 16;
140 		t = recallocarray(h->lines, h->cap, newcap,
141 		    sizeof(h->lines[0]));
142 		if (t == NULL)
143 			return got_error_from_errno("recallocarray");
144 		h->lines = t;
145 		h->cap = newcap;
146 	}
147 
148 	if ((t = strdup(line)) == NULL)
149 		return got_error_from_errno("strdup");
150 
151 	h->lines[h->len++] = t;
152 	return NULL;
153 }
154 
155 static const struct got_error *
156 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
157 {
158 	const struct got_error *err = NULL;
159 	struct imsg imsg;
160 	struct got_imsg_patch_hunk hdr;
161 	struct got_imsg_patch patch;
162 	struct got_patch_hunk *h = NULL;
163 	size_t datalen;
164 	int lastmode = -1;
165 
166 	memset(p, 0, sizeof(*p));
167 	STAILQ_INIT(&p->head);
168 
169 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
170 	if (err)
171 		return err;
172 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
173 		*done = 1;
174 		goto done;
175 	}
176 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
177 		err = got_error(GOT_ERR_PRIVSEP_MSG);
178 		goto done;
179 	}
180 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
181 	if (datalen != sizeof(patch)) {
182 		err = got_error(GOT_ERR_PRIVSEP_LEN);
183 		goto done;
184 	}
185 	memcpy(&patch, imsg.data, sizeof(patch));
186 
187 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
188 	    patch.new[sizeof(patch.new)-1] != '\0' ||
189 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
190 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
191 		err = got_error(GOT_ERR_PRIVSEP_LEN);
192 		goto done;
193 	}
194 
195 	if (*patch.cid != '\0')
196 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
197 
198 	if (*patch.blob != '\0')
199 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
200 
201 	/* automatically set strip=1 for git-style diffs */
202 	if (strip == -1 && patch.git &&
203 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
204 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
205 		strip = 1;
206 
207 	/* prefer the new name if not /dev/null for not git-style diffs */
208 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
209 		err = got_path_strip(&p->old, patch.new, strip);
210 		if (err)
211 			goto done;
212 	} else if (*patch.old != '\0') {
213 		err = got_path_strip(&p->old, patch.old, strip);
214 		if (err)
215 			goto done;
216 	}
217 
218 	if (*patch.new != '\0') {
219 		err = got_path_strip(&p->new, patch.new, strip);
220 		if (err)
221 			goto done;
222 	}
223 
224 	if (p->old == NULL && p->new == NULL) {
225 		err = got_error(GOT_ERR_PATCH_MALFORMED);
226 		goto done;
227 	}
228 
229 	imsg_free(&imsg);
230 
231 	for (;;) {
232 		char *t;
233 
234 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
235 		if (err) {
236 			patch_free(p);
237 			return err;
238 		}
239 
240 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
241 		switch (imsg.hdr.type) {
242 		case GOT_IMSG_PATCH_DONE:
243 			if (h != NULL && h->len == 0)
244 				err = got_error(GOT_ERR_PATCH_MALFORMED);
245 			goto done;
246 		case GOT_IMSG_PATCH_HUNK:
247 			if (h != NULL &&
248 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
249 				err = got_error(GOT_ERR_PATCH_MALFORMED);
250 				goto done;
251 			}
252 			lastmode = -1;
253 			if (datalen != sizeof(hdr)) {
254 				err = got_error(GOT_ERR_PRIVSEP_LEN);
255 				goto done;
256 			}
257 			memcpy(&hdr, imsg.data, sizeof(hdr));
258 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
259 				err = got_error(GOT_ERR_PRIVSEP_LEN);
260 				goto done;
261 			}
262 			if ((h = calloc(1, sizeof(*h))) == NULL) {
263 				err = got_error_from_errno("calloc");
264 				goto done;
265 			}
266 			h->old_from = hdr.oldfrom;
267 			h->old_lines = hdr.oldlines;
268 			h->new_from = hdr.newfrom;
269 			h->new_lines = hdr.newlines;
270 			STAILQ_INSERT_TAIL(&p->head, h, entries);
271 			break;
272 		case GOT_IMSG_PATCH_LINE:
273 			if (h == NULL) {
274 				err = got_error(GOT_ERR_PRIVSEP_MSG);
275 				goto done;
276 			}
277 			t = imsg.data;
278 			/* at least one char */
279 			if (datalen < 2 || t[datalen-1] != '\0') {
280 				err = got_error(GOT_ERR_PRIVSEP_MSG);
281 				goto done;
282 			}
283 			if (*t != ' ' && *t != '-' && *t != '+' &&
284 			    *t != '\\') {
285 				err = got_error(GOT_ERR_PRIVSEP_MSG);
286 				goto done;
287 			}
288 
289 			if (*t != '\\')
290 				err = pushline(h, t);
291 			else if (lastmode == '-')
292 				h->old_nonl = 1;
293 			else if (lastmode == '+')
294 				h->new_nonl = 1;
295 			else
296 				err = got_error(GOT_ERR_PATCH_MALFORMED);
297 
298 			if (err)
299 				goto done;
300 
301 			lastmode = *t;
302 			break;
303 		default:
304 			err = got_error(GOT_ERR_PRIVSEP_MSG);
305 			goto done;
306 		}
307 
308 		imsg_free(&imsg);
309 	}
310 
311 done:
312 	if (err)
313 		patch_free(p);
314 
315 	imsg_free(&imsg);
316 	return err;
317 }
318 
319 /*
320  * Copy data from orig starting at copypos until pos into tmp.
321  * If pos is -1, copy until EOF.
322  */
323 static const struct got_error *
324 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
325 {
326 	char buf[BUFSIZ];
327 	size_t len, r, w;
328 
329 	if (fseeko(orig, copypos, SEEK_SET) == -1)
330 		return got_error_from_errno("fseeko");
331 
332 	while (pos == -1 || copypos < pos) {
333 		len = sizeof(buf);
334 		if (pos > 0)
335 			len = MIN(len, (size_t)pos - copypos);
336 		r = fread(buf, 1, len, orig);
337 		if (r != len && ferror(orig))
338 			return got_error_from_errno("fread");
339 		w = fwrite(buf, 1, r, tmp);
340 		if (w != r)
341 			return got_error_from_errno("fwrite");
342 		copypos += len;
343 		if (r != len && feof(orig)) {
344 			if (pos == -1)
345 				return NULL;
346 			return got_error(GOT_ERR_HUNK_FAILED);
347 		}
348 	}
349 	return NULL;
350 }
351 
352 static const struct got_error *
353 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
354 {
355 	const struct got_error *err = NULL;
356 	char *line = NULL;
357 	char mode = *h->lines[0];
358 	size_t linesize = 0;
359 	ssize_t linelen;
360 	off_t match = -1;
361 	int match_lineno = -1;
362 
363 	for (;;) {
364 		linelen = getline(&line, &linesize, orig);
365 		if (linelen == -1) {
366 			if (ferror(orig))
367 				err = got_error_from_errno("getline");
368 			else if (match == -1)
369 				err = got_error(GOT_ERR_HUNK_FAILED);
370 			break;
371 		}
372 		if (line[linelen - 1] == '\n')
373 			line[linelen - 1] = '\0';
374 		(*lineno)++;
375 
376 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
377 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
378 		    (mode == '+' && *lineno == h->old_from)) {
379 			match = ftello(orig);
380 			if (match == -1) {
381 				err = got_error_from_errno("ftello");
382 				break;
383 			}
384 			match -= linelen;
385 			match_lineno = (*lineno)-1;
386 		}
387 
388 		if (*lineno >= h->old_from && match != -1)
389 			break;
390 	}
391 
392 	if (err == NULL) {
393 		*pos = match;
394 		*lineno = match_lineno;
395 		if (fseeko(orig, match, SEEK_SET) == -1)
396 			err = got_error_from_errno("fseeko");
397 	}
398 
399 	free(line);
400 	return err;
401 }
402 
403 static const struct got_error *
404 test_hunk(FILE *orig, struct got_patch_hunk *h)
405 {
406 	const struct got_error *err = NULL;
407 	char *line = NULL;
408 	size_t linesize = 0, i = 0;
409 	ssize_t linelen;
410 
411 	for (i = 0; i < h->len; ++i) {
412 		switch (*h->lines[i]) {
413 		case '+':
414 			continue;
415 		case ' ':
416 		case '-':
417 			linelen = getline(&line, &linesize, orig);
418 			if (linelen == -1) {
419 				if (ferror(orig))
420 					err = got_error_from_errno("getline");
421 				else
422 					err = got_error(
423 					    GOT_ERR_HUNK_FAILED);
424 				goto done;
425 			}
426 			if (line[linelen - 1] == '\n')
427 				line[linelen - 1] = '\0';
428 			if (strcmp(h->lines[i] + 1, line)) {
429 				err = got_error(GOT_ERR_HUNK_FAILED);
430 				goto done;
431 			}
432 			break;
433 		}
434 	}
435 
436 done:
437 	free(line);
438 	return err;
439 }
440 
441 static const struct got_error *
442 apply_hunk(FILE *tmp, struct got_patch_hunk *h, int *lineno)
443 {
444 	size_t i, new = 0;
445 
446 	for (i = 0; i < h->len; ++i) {
447 		switch (*h->lines[i]) {
448 		case ' ':
449 			if (fprintf(tmp, "%s\n", h->lines[i] + 1) < 0)
450 				return got_error_from_errno("fprintf");
451 			/* fallthrough */
452 		case '-':
453 			(*lineno)++;
454 			break;
455 		case '+':
456 			new++;
457 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0)
458 				return got_error_from_errno("fprintf");
459 			if (new != h->new_lines || !h->new_nonl) {
460 				if (fprintf(tmp, "\n") < 0)
461 					return got_error_from_errno(
462 					    "fprintf");
463 			}
464 			break;
465 		}
466 	}
467 	return NULL;
468 }
469 
470 static const struct got_error *
471 patch_file(struct got_patch *p, FILE *orig, FILE *tmp, mode_t *mode)
472 {
473 	const struct got_error *err = NULL;
474 	struct got_patch_hunk *h;
475 	struct stat sb;
476 	int lineno = 0;
477 	off_t copypos, pos;
478 	char *line = NULL;
479 	size_t linesize = 0;
480 	ssize_t linelen;
481 
482 	if (p->old == NULL) {				/* create */
483 		h = STAILQ_FIRST(&p->head);
484 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
485 			return got_error(GOT_ERR_PATCH_MALFORMED);
486 		return apply_hunk(tmp, h, &lineno);
487 	}
488 
489 	if (fstat(fileno(orig), &sb) == -1)
490 		return got_error_from_errno("fstat");
491 	*mode = sb.st_mode;
492 
493 	copypos = 0;
494 	STAILQ_FOREACH(h, &p->head, entries) {
495 	tryagain:
496 		err = locate_hunk(orig, h, &pos, &lineno);
497 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
498 			h->err = err;
499 		if (err != NULL)
500 			return err;
501 		err = copy(tmp, orig, copypos, pos);
502 		if (err != NULL)
503 			return err;
504 		copypos = pos;
505 
506 		err = test_hunk(orig, h);
507 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
508 			/*
509 			 * try to apply the hunk again starting the search
510 			 * after the previous partial match.
511 			 */
512 			if (fseeko(orig, pos, SEEK_SET) == -1)
513 				return got_error_from_errno("fseeko");
514 			linelen = getline(&line, &linesize, orig);
515 			if (linelen == -1)
516 				return got_error_from_errno("getline");
517 			lineno++;
518 			goto tryagain;
519 		}
520 		if (err != NULL)
521 			return err;
522 
523 		if (lineno + 1 != h->old_from)
524 			h->offset = lineno + 1 - h->old_from;
525 
526 		err = apply_hunk(tmp, h, &lineno);
527 		if (err != NULL)
528 			return err;
529 
530 		copypos = ftello(orig);
531 		if (copypos == -1)
532 			return got_error_from_errno("ftello");
533 	}
534 
535 	if (p->new == NULL && sb.st_size != copypos) {
536 		h = STAILQ_FIRST(&p->head);
537 		h->err = got_error(GOT_ERR_HUNK_FAILED);
538 		err = h->err;
539 	} else if (!feof(orig))
540 		err = copy(tmp, orig, copypos, -1);
541 
542 	return err;
543 }
544 
545 static const struct got_error *
546 report_progress(struct patch_args *pa, const char *old, const char *new,
547     unsigned char status, const struct got_error *orig_error)
548 {
549 	const struct got_error *err;
550 	struct got_patch_hunk *h;
551 
552 	err = pa->progress_cb(pa->progress_arg, old, new, status,
553 	    orig_error, 0, 0, 0, 0, 0, NULL);
554 	if (err)
555 		return err;
556 
557 	STAILQ_FOREACH(h, pa->head, entries) {
558 		if (h->offset == 0 && h->err == NULL)
559 			continue;
560 
561 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
562 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
563 		    h->offset, h->err);
564 		if (err)
565 			return err;
566 	}
567 
568 	return NULL;
569 }
570 
571 static const struct got_error *
572 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
573     const char *path)
574 {
575 	return report_progress(arg, path, NULL, status, NULL);
576 }
577 
578 static const struct got_error *
579 patch_add(void *arg, unsigned char status, const char *path)
580 {
581 	return report_progress(arg, NULL, path, status, NULL);
582 }
583 
584 static const struct got_error *
585 open_blob(char **path, FILE **fp, const char *blobid,
586     struct got_repository *repo)
587 {
588 	const struct got_error *err = NULL;
589 	struct got_blob_object *blob = NULL;
590 	struct got_object_id id, *idptr, *matched_id = NULL;
591 	int fd = -1;
592 
593 	*fp = NULL;
594 	*path = NULL;
595 
596 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
597 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
598 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
599 		    repo);
600 		if (err)
601 			return err;
602 		idptr = matched_id;
603 	} else {
604 		if (!got_parse_sha1_digest(id.sha1, blobid))
605 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
606 		idptr = &id;
607 	}
608 
609 	fd = got_opentempfd();
610 	if (fd == -1) {
611 		err = got_error_from_errno("got_opentempfd");
612 		goto done;
613 	}
614 
615 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
616 	if (err)
617 		goto done;
618 
619 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
620 	if (err)
621 		goto done;
622 
623 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
624 	if (err)
625 		goto done;
626 
627 done:
628 	if (fd != -1 && close(fd) == -1 && err == NULL)
629 		err = got_error_from_errno("close");
630 	if (blob)
631 		got_object_blob_close(blob);
632 	if (matched_id != NULL)
633 		free(matched_id);
634 	if (err) {
635 		if (*fp != NULL)
636 			fclose(*fp);
637 		if (*path != NULL)
638 			unlink(*path);
639 		free(*path);
640 		*fp = NULL;
641 		*path = NULL;
642 	}
643 	return err;
644 }
645 
646 static const struct got_error *
647 apply_patch(int *overlapcnt, struct got_worktree *worktree,
648     struct got_repository *repo, struct got_fileindex *fileindex,
649     const char *old, const char *new, struct got_patch *p, int nop,
650     struct patch_args *pa, got_cancel_cb cancel_cb, void *cancel_arg)
651 {
652 	const struct got_error *err = NULL;
653 	int do_merge = 0, file_renamed = 0;
654 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
655 	char *oldpath = NULL, *newpath = NULL;
656 	char *tmppath = NULL, *template = NULL, *parent = NULL;
657 	char *apath = NULL, *mergepath = NULL;
658 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
659 	int outfd;
660 	const char *outpath;
661 	mode_t mode = GOT_DEFAULT_FILE_MODE;
662 
663 	*overlapcnt = 0;
664 
665 	/* don't run the diff3 merge on creations/deletions */
666 	if (*p->blob != '\0' && p->old != NULL && p->new != NULL) {
667 		err = open_blob(&apath, &afile, p->blob, repo);
668 		/*
669 		 * ignore failures to open this blob, we might have
670 		 * parsed gibberish.
671 		 */
672 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
673 		    err->code != GOT_ERR_NO_OBJ)
674 			return err;
675 		else if (err == NULL)
676 			do_merge = 1;
677 		err = NULL;
678 	}
679 
680 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
681 	    old) == -1) {
682 		err = got_error_from_errno("asprintf");
683 		goto done;
684 	}
685 
686 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
687 	    new) == -1) {
688 		err = got_error_from_errno("asprintf");
689 		goto done;
690 	}
691 
692 	file_renamed = strcmp(oldpath, newpath);
693 
694 	if (asprintf(&template, "%s/got-patch",
695 	    got_worktree_get_root_path(worktree)) == -1) {
696 		err = got_error_from_errno(template);
697 		goto done;
698 	}
699 
700 	if (p->old != NULL && (oldfile = fopen(oldpath, "r")) == NULL) {
701 		err = got_error_from_errno2("open", oldpath);
702 		goto done;
703 	}
704 
705 	err = got_opentemp_named(&tmppath, &tmpfile, template);
706 	if (err)
707 		goto done;
708 	outpath = tmppath;
709 	outfd = fileno(tmpfile);
710 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile, &mode);
711 	if (err)
712 		goto done;
713 
714 	if (do_merge) {
715 		const char *type, *id;
716 
717 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
718 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
719 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
720 			err = got_error_from_errno("fseeko");
721 			goto done;
722 		}
723 
724 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
725 			err = got_error_from_errno("asprintf");
726 			oldlabel = NULL;
727 			goto done;
728 		}
729 
730 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
731 			err = got_error_from_errno("asprintf");
732 			newlabel = NULL;
733 			goto done;
734 		}
735 
736 		if (*p->cid != '\0') {
737 			type = "commit";
738 			id = p->cid;
739 		} else {
740 			type = "blob";
741 			id = p->blob;
742 		}
743 
744 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
745 			err = got_error_from_errno("asprintf");
746 			anclabel = NULL;
747 			goto done;
748 		}
749 
750 		err = got_opentemp_named(&mergepath, &mergefile, template);
751 		if (err)
752 			goto done;
753 		outpath = mergepath;
754 		outfd = fileno(mergefile);
755 
756 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
757 		    oldfile, oldlabel, anclabel, newlabel,
758 		    GOT_DIFF_ALGORITHM_PATIENCE);
759 		if (err)
760 			goto done;
761 	}
762 
763 	if (nop)
764 		goto done;
765 
766 	if (p->old != NULL && p->new == NULL) {
767 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
768 		    fileindex, patch_delete, pa);
769 		goto done;
770 	}
771 
772 	if (fchmod(outfd, mode) == -1) {
773 		err = got_error_from_errno2("chmod", tmppath);
774 		goto done;
775 	}
776 
777 	if (rename(outpath, newpath) == -1) {
778 		if (errno != ENOENT) {
779 			err = got_error_from_errno3("rename", outpath,
780 			    newpath);
781 			goto done;
782 		}
783 
784 		err = got_path_dirname(&parent, newpath);
785 		if (err != NULL)
786 			goto done;
787 		err = got_path_mkdir(parent);
788 		if (err != NULL)
789 			goto done;
790 		if (rename(outpath, newpath) == -1) {
791 			err = got_error_from_errno3("rename", outpath,
792 			    newpath);
793 			goto done;
794 		}
795 	}
796 
797 	if (file_renamed) {
798 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
799 		    fileindex, patch_delete, pa);
800 		if (err == NULL)
801 			err = got_worktree_patch_schedule_add(new, repo,
802 			    worktree, fileindex, patch_add,
803 			    pa);
804 		if (err)
805 			unlink(newpath);
806 	} else if (p->old == NULL) {
807 		err = got_worktree_patch_schedule_add(new, repo, worktree,
808 		    fileindex, patch_add, pa);
809 		if (err)
810 			unlink(newpath);
811 	} else if (*overlapcnt != 0)
812 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
813 	else if (do_merge)
814 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
815 	else
816 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
817 
818 done:
819 	free(parent);
820 	free(template);
821 
822 	if (tmppath != NULL)
823 		unlink(tmppath);
824 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
825 		err = got_error_from_errno("fclose");
826 	free(tmppath);
827 
828 	free(oldpath);
829 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
830 		err = got_error_from_errno("fclose");
831 
832 	if (apath != NULL)
833 		unlink(apath);
834 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
835 		err = got_error_from_errno("fclose");
836 	free(apath);
837 
838 	if (mergepath != NULL)
839 		unlink(mergepath);
840 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
841 		err = got_error_from_errno("fclose");
842 	free(mergepath);
843 
844 	free(newpath);
845 	free(oldlabel);
846 	free(newlabel);
847 	free(anclabel);
848 	return err;
849 }
850 
851 static void
852 reverse_patch(struct got_patch *p)
853 {
854 	struct got_patch_hunk *h;
855 	size_t i;
856 	int tmp;
857 
858 	STAILQ_FOREACH(h, &p->head, entries) {
859 		tmp = h->old_from;
860 		h->old_from = h->new_from;
861 		h->new_from = tmp;
862 
863 		tmp = h->old_lines;
864 		h->old_lines = h->new_lines;
865 		h->new_lines = tmp;
866 
867 		tmp = h->old_nonl;
868 		h->old_nonl = h->new_nonl;
869 		h->new_nonl = tmp;
870 
871 		for (i = 0; i < h->len; ++i) {
872 			if (*h->lines[i] == '+')
873 				*h->lines[i] = '-';
874 			else if (*h->lines[i] == '-')
875 				*h->lines[i] = '+';
876 		}
877 	}
878 }
879 
880 const struct got_error *
881 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
882     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
883     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
884 {
885 	const struct got_error *err = NULL, *complete_err = NULL;
886 	struct got_fileindex *fileindex = NULL;
887 	char *fileindex_path = NULL;
888 	char *oldpath, *newpath;
889 	struct imsgbuf *ibuf;
890 	int imsg_fds[2] = {-1, -1};
891 	int overlapcnt, done = 0, failed = 0;
892 	pid_t pid;
893 
894 	ibuf = calloc(1, sizeof(*ibuf));
895 	if (ibuf == NULL) {
896 		err = got_error_from_errno("calloc");
897 		goto done;
898 	}
899 
900 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
901 		err = got_error_from_errno("socketpair");
902 		goto done;
903 	}
904 
905 	pid = fork();
906 	if (pid == -1) {
907 		err = got_error_from_errno("fork");
908 		goto done;
909 	} else if (pid == 0) {
910 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
911 		    NULL);
912 		/* not reached */
913 	}
914 
915 	if (close(imsg_fds[1]) == -1) {
916 		err = got_error_from_errno("close");
917 		goto done;
918 	}
919 	imsg_fds[1] = -1;
920 	imsg_init(ibuf, imsg_fds[0]);
921 
922 	err = send_patch(ibuf, fd);
923 	fd = -1;
924 	if (err)
925 		goto done;
926 
927 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
928 	    worktree);
929 	if (err)
930 		goto done;
931 
932 	while (!done && err == NULL) {
933 		struct got_patch p;
934 		struct patch_args pa;
935 
936 		pa.progress_cb = progress_cb;
937 		pa.progress_arg = progress_arg;
938 		pa.head = &p.head;
939 
940 		err = recv_patch(ibuf, &done, &p, strip);
941 		if (err || done)
942 			break;
943 
944 		if (reverse)
945 			reverse_patch(&p);
946 
947 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
948 		    &newpath, worktree, repo, fileindex);
949 		if (err == NULL)
950 			err = apply_patch(&overlapcnt, worktree, repo,
951 			    fileindex, oldpath, newpath, &p, nop, &pa,
952 			    cancel_cb, cancel_arg);
953 		if (err != NULL) {
954 			failed = 1;
955 			/* recoverable errors */
956 			if (err->code == GOT_ERR_FILE_STATUS ||
957 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
958 				err = report_progress(&pa, p.old, p.new,
959 				    GOT_STATUS_CANNOT_UPDATE, err);
960 			else if (err->code == GOT_ERR_HUNK_FAILED)
961 				err = report_progress(&pa, p.old, p.new,
962 				    GOT_STATUS_CANNOT_UPDATE, NULL);
963 		}
964 		if (overlapcnt != 0)
965 			failed = 1;
966 
967 		free(oldpath);
968 		free(newpath);
969 		patch_free(&p);
970 
971 		if (err)
972 			break;
973 	}
974 
975 done:
976 	if (fileindex != NULL)
977 		complete_err = got_worktree_patch_complete(fileindex,
978 		    fileindex_path);
979 	if (complete_err && err == NULL)
980 		err = complete_err;
981 	free(fileindex_path);
982 	if (fd != -1 && close(fd) == -1 && err == NULL)
983 		err = got_error_from_errno("close");
984 	if (ibuf != NULL)
985 		imsg_clear(ibuf);
986 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
987 		err = got_error_from_errno("close");
988 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
989 		err = got_error_from_errno("close");
990 	if (err == NULL && failed)
991 		err = got_error(GOT_ERR_PATCH_FAILED);
992 	return err;
993 }