summaryrefslogtreecommitdiff
path: root/builtin/update-index.c
blob: 890c251d665a1b6800b87cc6ee0fcb04a3f9f538 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#define USE_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "config.h"
#include "lockfile.h"
#include "quote.h"
#include "cache-tree.h"
#include "tree-walk.h"
#include "builtin.h"
#include "refs.h"
#include "resolve-undo.h"
#include "parse-options.h"
#include "pathspec.h"
#include "dir.h"
#include "split-index.h"
#include "fsmonitor.h"

/*
 * Default to not allowing changes to the list of files. The
 * tool doesn't actually care, but this makes it harder to add
 * files to the revision control by mistake by doing something
 * like "git update-index *" and suddenly having all the object
 * files be revision controlled.
 */
static int allow_add;
static int allow_remove;
static int allow_replace;
static int info_only;
static int force_remove;
static int verbose;
static int mark_valid_only;
static int mark_skip_worktree_only;
static int mark_fsmonitor_only;
#define MARK_FLAG 1
#define UNMARK_FLAG 2
static struct strbuf mtime_dir = STRBUF_INIT;

/* Untracked cache mode */
enum uc_mode {
	UC_UNSPECIFIED = -1,
	UC_DISABLE = 0,
	UC_ENABLE,
	UC_TEST,
	UC_FORCE
};

__attribute__((format (printf, 1, 2)))
static void report(const char *fmt, ...)
{
	va_list vp;

	if (!verbose)
		return;

	va_start(vp, fmt);
	vprintf(fmt, vp);
	putchar('\n');
	va_end(vp);
}

static void remove_test_directory(void)
{
	if (mtime_dir.len)
		remove_dir_recursively(&mtime_dir, 0);
}

static const char *get_mtime_path(const char *path)
{
	static struct strbuf sb = STRBUF_INIT;
	strbuf_reset(&sb);
	strbuf_addf(&sb, "%s/%s", mtime_dir.buf, path);
	return sb.buf;
}

static void xmkdir(const char *path)
{
	path = get_mtime_path(path);
	if (mkdir(path, 0700))
		die_errno(_("failed to create directory %s"), path);
}

static int xstat_mtime_dir(struct stat *st)
{
	if (stat(mtime_dir.buf, st))
		die_errno(_("failed to stat %s"), mtime_dir.buf);
	return 0;
}

static int create_file(const char *path)
{
	int fd;
	path = get_mtime_path(path);
	fd = open(path, O_CREAT | O_RDWR, 0644);
	if (fd < 0)
		die_errno(_("failed to create file %s"), path);
	return fd;
}

static void xunlink(const char *path)
{
	path = get_mtime_path(path);
	if (unlink(path))
		die_errno(_("failed to delete file %s"), path);
}

static void xrmdir(const char *path)
{
	path = get_mtime_path(path);
	if (rmdir(path))
		die_errno(_("failed to delete directory %s"), path);
}

static void avoid_racy(void)
{
	/*
	 * not use if we could usleep(10) if USE_NSEC is defined. The
	 * field nsec could be there, but the OS could choose to
	 * ignore it?
	 */
	sleep(1);
}

static int test_if_untracked_cache_is_supported(void)
{
	struct stat st;
	struct stat_data base;
	int fd, ret = 0;
	char *cwd;

	strbuf_addstr(&mtime_dir, "mtime-test-XXXXXX");
	if (!mkdtemp(mtime_dir.buf))
		die_errno("Could not make temporary directory");

	cwd = xgetcwd();
	fprintf(stderr, _("Testing mtime in '%s' "), cwd);
	free(cwd);

	atexit(remove_test_directory);
	xstat_mtime_dir(&st);
	fill_stat_data(&base, &st);
	fputc('.', stderr);

	avoid_racy();
	fd = create_file("newfile");
	xstat_mtime_dir(&st);
	if (!match_stat_data(&base, &st)) {
		close(fd);
		fputc('\n', stderr);
		fprintf_ln(stderr,_("directory stat info does not "
				    "change after adding a new file"));
		goto done;
	}
	fill_stat_data(&base, &st);
	fputc('.', stderr);

	avoid_racy();
	xmkdir("new-dir");
	xstat_mtime_dir(&st);
	if (!match_stat_data(&base, &st)) {
		close(fd);
		fputc('\n', stderr);
		fprintf_ln(stderr, _("directory stat info does not change "
				     "after adding a new directory"));
		goto done;
	}
	fill_stat_data(&base, &st);
	fputc('.', stderr);

	avoid_racy();
	write_or_die(fd, "data", 4);
	close(fd);
	xstat_mtime_dir(&st);
	if (match_stat_data(&base, &st)) {
		fputc('\n', stderr);
		fprintf_ln(stderr, _("directory stat info changes "
				     "after updating a file"));
		goto done;
	}
	fputc('.', stderr);

	avoid_racy();
	close(create_file("new-dir/new"));
	xstat_mtime_dir(&st);
	if (match_stat_data(&base, &st)) {
		fputc('\n', stderr);
		fprintf_ln(stderr, _("directory stat info changes after "
				     "adding a file inside subdirectory"));
		goto done;
	}
	fputc('.', stderr);

	avoid_racy();
	xunlink("newfile");
	xstat_mtime_dir(&st);
	if (!match_stat_data(&base, &st)) {
		fputc('\n', stderr);
		fprintf_ln(stderr, _("directory stat info does not "
				     "change after deleting a file"));
		goto done;
	}
	fill_stat_data(&base, &st);
	fputc('.', stderr);

	avoid_racy();
	xunlink("new-dir/new");
	xrmdir("new-dir");
	xstat_mtime_dir(&st);
	if (!match_stat_data(&base, &st)) {
		fputc('\n', stderr);
		fprintf_ln(stderr, _("directory stat info does not "
				     "change after deleting a directory"));
		goto done;
	}

	if (rmdir(mtime_dir.buf))
		die_errno(_("failed to delete directory %s"), mtime_dir.buf);
	fprintf_ln(stderr, _(" OK"));
	ret = 1;

done:
	strbuf_release(&mtime_dir);
	return ret;
}

static int mark_ce_flags(const char *path, int flag, int mark)
{
	int namelen = strlen(path);
	int pos = cache_name_pos(path, namelen);
	if (0 <= pos) {
		mark_fsmonitor_invalid(&the_index, active_cache[pos]);
		if (mark)
			active_cache[pos]->ce_flags |= flag;
		else
			active_cache[pos]->ce_flags &= ~flag;
		active_cache[pos]->ce_flags |= CE_UPDATE_IN_BASE;
		cache_tree_invalidate_path(&the_index, path);
		active_cache_changed |= CE_ENTRY_CHANGED;
		return 0;
	}
	return -1;
}

static int remove_one_path(const char *path)
{
	if (!allow_remove)
		return error("%s: does not exist and --remove not passed", path);
	if (remove_file_from_cache(path))
		return error("%s: cannot remove from the index", path);
	return 0;
}

/*
 * Handle a path that couldn't be lstat'ed. It's either:
 *  - missing file (ENOENT or ENOTDIR). That's ok if we're
 *    supposed to be removing it and the removal actually
 *    succeeds.
 *  - permission error. That's never ok.
 */
static int process_lstat_error(const char *path, int err)
{
	if (is_missing_file_error(err))
		return remove_one_path(path);
	return error("lstat(\"%s\"): %s", path, strerror(err));
}

static int add_one_path(const struct cache_entry *old, const char *path, int len, struct stat *st)
{
	int option;
	struct cache_entry *ce;

	/* Was the old index entry already up-to-date? */
	if (old && !ce_stage(old) && !ce_match_stat(old, st, 0))
		return 0;

	ce = make_empty_cache_entry(&the_index, len);
	memcpy(ce->name, path, len);
	ce->ce_flags = create_ce_flags(0);
	ce->ce_namelen = len;
	fill_stat_cache_info(ce, st);
	ce->ce_mode = ce_mode_from_stat(old, st->st_mode);

	if (index_path(&the_index, &ce->oid, path, st,
		       info_only ? 0 : HASH_WRITE_OBJECT)) {
		discard_cache_entry(ce);
		return -1;
	}
	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
	if (add_cache_entry(ce, option)) {
		discard_cache_entry(ce);
		return error("%s: cannot add to the index - missing --add option?", path);
	}
	return 0;
}

/*
 * Handle a path that was a directory. Four cases:
 *
 *  - it's already a gitlink in the index, and we keep it that
 *    way, and update it if we can (if we cannot find the HEAD,
 *    we're going to keep it unchanged in the index!)
 *
 *  - it's a *file* in the index, in which case it should be
 *    removed as a file if removal is allowed, since it doesn't
 *    exist as such any more. If removal isn't allowed, it's
 *    an error.
 *
 *    (NOTE! This is old and arguably fairly strange behaviour.
 *    We might want to make this an error unconditionally, and
 *    use "--force-remove" if you actually want to force removal).
 *
 *  - it used to exist as a subdirectory (ie multiple files with
 *    this particular prefix) in the index, in which case it's wrong
 *    to try to update it as a directory.
 *
 *  - it doesn't exist at all in the index, but it is a valid
 *    git directory, and it should be *added* as a gitlink.
 */
static int process_directory(const char *path, int len, struct stat *st)
{
	struct object_id oid;
	int pos = cache_name_pos(path, len);

	/* Exact match: file or existing gitlink */
	if (pos >= 0) {
		const struct cache_entry *ce = active_cache[pos];
		if (S_ISGITLINK(ce->ce_mode)) {

			/* Do nothing to the index if there is no HEAD! */
			if (resolve_gitlink_ref(path, "HEAD", &oid) < 0)
				return 0;

			return add_one_path(ce, path, len, st);
		}
		/* Should this be an unconditional error? */
		return remove_one_path(path);
	}

	/* Inexact match: is there perhaps a subdirectory match? */
	pos = -pos-1;
	while (pos < active_nr) {
		const struct cache_entry *ce = active_cache[pos++];

		if (strncmp(ce->name, path, len))
			break;
		if (ce->name[len] > '/')
			break;
		if (ce->name[len] < '/')
			continue;

		/* Subdirectory match - error out */
		return error("%s: is a directory - add individual files instead", path);
	}

	/* No match - should we add it as a gitlink? */
	if (!resolve_gitlink_ref(path, "HEAD", &oid))
		return add_one_path(NULL, path, len, st);

	/* Error out. */
	return error("%s: is a directory - add files inside instead", path);
}

static int process_path(const char *path, struct stat *st, int stat_errno)
{
	int pos, len;
	const struct cache_entry *ce;

	len = strlen(path);
	if (has_symlink_leading_path(path, len))
		return error("'%s' is beyond a symbolic link", path);

	pos = cache_name_pos(path, len);
	ce = pos < 0 ? NULL : active_cache[pos];
	if (ce && ce_skip_worktree(ce)) {
		/*
		 * working directory version is assumed "good"
		 * so updating it does not make sense.
		 * On the other hand, removing it from index should work
		 */
		if (allow_remove && remove_file_from_cache(path))
			return error("%s: cannot remove from the index", path);
		return 0;
	}

	/*
	 * First things first: get the stat information, to decide
	 * what to do about the pathname!
	 */
	if (stat_errno)
		return process_lstat_error(path, stat_errno);

	if (S_ISDIR(st->st_mode))
		return process_directory(path, len, st);

	return add_one_path(ce, path, len, st);
}

static int add_cacheinfo(unsigned int mode, const struct object_id *oid,
			 const char *path, int stage)
{
	int len, option;
	struct cache_entry *ce;

	if (!verify_path(path, mode))
		return error("Invalid path '%s'", path);

	len = strlen(path);
	ce = make_empty_cache_entry(&the_index, len);

	oidcpy(&ce->oid, oid);
	memcpy(ce->name, path, len);
	ce->ce_flags = create_ce_flags(stage);
	ce->ce_namelen = len;
	ce->ce_mode = create_ce_mode(mode);
	if (assume_unchanged)
		ce->ce_flags |= CE_VALID;
	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
	if (add_cache_entry(ce, option))
		return error("%s: cannot add to the index - missing --add option?",
			     path);
	report("add '%s'", path);
	return 0;
}

static void chmod_path(char flip, const char *path)
{
	int pos;
	struct cache_entry *ce;

	pos = cache_name_pos(path, strlen(path));
	if (pos < 0)
		goto fail;
	ce = active_cache[pos];
	if (chmod_cache_entry(ce, flip) < 0)
		goto fail;

	report("chmod %cx '%s'", flip, path);
	return;
 fail:
	die("git update-index: cannot chmod %cx '%s'", flip, path);
}

static void update_one(const char *path)
{
	int stat_errno = 0;
	struct stat st;

	if (mark_valid_only || mark_skip_worktree_only || force_remove ||
	    mark_fsmonitor_only)
		st.st_mode = 0;
	else if (lstat(path, &st) < 0) {
		st.st_mode = 0;
		stat_errno = errno;
	} /* else stat is valid */

	if (!verify_path(path, st.st_mode)) {
		fprintf(stderr, "Ignoring path %s\n", path);
		return;
	}
	if (mark_valid_only) {
		if (mark_ce_flags(path, CE_VALID, mark_valid_only == MARK_FLAG))
			die("Unable to mark file %s", path);
		return;
	}
	if (mark_skip_worktree_only) {
		if (mark_ce_flags(path, CE_SKIP_WORKTREE, mark_skip_worktree_only == MARK_FLAG))
			die("Unable to mark file %s", path);
		return;
	}
	if (mark_fsmonitor_only) {
		if (mark_ce_flags(path, CE_FSMONITOR_VALID, mark_fsmonitor_only == MARK_FLAG))
			die("Unable to mark file %s", path);
		return;
	}

	if (force_remove) {
		if (remove_file_from_cache(path))
			die("git update-index: unable to remove %s", path);
		report("remove '%s'", path);
		return;
	}
	if (process_path(path, &st, stat_errno))
		die("Unable to process path %s", path);
	report("add '%s'", path);
}

static void read_index_info(int nul_term_line)
{
	const int hexsz = the_hash_algo->hexsz;
	struct strbuf buf = STRBUF_INIT;
	struct strbuf uq = STRBUF_INIT;
	strbuf_getline_fn getline_fn;

	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
	while (getline_fn(&buf, stdin) != EOF) {
		char *ptr, *tab;
		char *path_name;
		struct object_id oid;
		unsigned int mode;
		unsigned long ul;
		int stage;

		/* This reads lines formatted in one of three formats:
		 *
		 * (1) mode         SP sha1          TAB path
		 * The first format is what "git apply --index-info"
		 * reports, and used to reconstruct a partial tree
		 * that is used for phony merge base tree when falling
		 * back on 3-way merge.
		 *
		 * (2) mode SP type SP sha1          TAB path
		 * The second format is to stuff "git ls-tree" output
		 * into the index file.
		 *
		 * (3) mode         SP sha1 SP stage TAB path
		 * This format is to put higher order stages into the
		 * index file and matches "git ls-files --stage" output.
		 */
		errno = 0;
		ul = strtoul(buf.buf, &ptr, 8);
		if (ptr == buf.buf || *ptr != ' '
		    || errno || (unsigned int) ul != ul)
			goto bad_line;
		mode = ul;

		tab = strchr(ptr, '\t');
		if (!tab || tab - ptr < hexsz + 1)
			goto bad_line;

		if (tab[-2] == ' ' && '0' <= tab[-1] && tab[-1] <= '3') {
			stage = tab[-1] - '0';
			ptr = tab + 1; /* point at the head of path */
			tab = tab - 2; /* point at tail of sha1 */
		}
		else {
			stage = 0;
			ptr = tab + 1; /* point at the head of path */
		}

		if (get_oid_hex(tab - hexsz, &oid) ||
			tab[-(hexsz + 1)] != ' ')
			goto bad_line;

		path_name = ptr;
		if (!nul_term_line && path_name[0] == '"') {
			strbuf_reset(&uq);
			if (unquote_c_style(&uq, path_name, NULL)) {
				die("git update-index: bad quoting of path name");
			}
			path_name = uq.buf;
		}

		if (!verify_path(path_name, mode)) {
			fprintf(stderr, "Ignoring path %s\n", path_name);
			continue;
		}

		if (!mode) {
			/* mode == 0 means there is no such path -- remove */
			if (remove_file_from_cache(path_name))
				die("git update-index: unable to remove %s",
				    ptr);
		}
		else {
			/* mode ' ' sha1 '\t' name
			 * ptr[-1] points at tab,
			 * ptr[-41] is at the beginning of sha1
			 */
			ptr[-(hexsz + 2)] = ptr[-1] = 0;
			if (add_cacheinfo(mode, &oid, path_name, stage))
				die("git update-index: unable to update %s",
				    path_name);
		}
		continue;

	bad_line:
		die("malformed index info %s", buf.buf);
	}
	strbuf_release(&buf);
	strbuf_release(&uq);
}

static const char * const update_index_usage[] = {
	N_("git update-index [<options>] [--] [<file>...]"),
	NULL
};

static struct object_id head_oid;
static struct object_id merge_head_oid;

static struct cache_entry *read_one_ent(const char *which,
					struct object_id *ent, const char *path,
					int namelen, int stage)
{
	unsigned mode;
	struct object_id oid;
	struct cache_entry *ce;

	if (get_tree_entry(ent, path, &oid, &mode)) {
		if (which)
			error("%s: not in %s branch.", path, which);
		return NULL;
	}
	if (mode == S_IFDIR) {
		if (which)
			error("%s: not a blob in %s branch.", path, which);
		return NULL;
	}
	ce = make_empty_cache_entry(&the_index, namelen);

	oidcpy(&ce->oid, &oid);
	memcpy(ce->name, path, namelen);
	ce->ce_flags = create_ce_flags(stage);
	ce->ce_namelen = namelen;
	ce->ce_mode = create_ce_mode(mode);
	return ce;
}

static int unresolve_one(const char *path)
{
	int namelen = strlen(path);
	int pos;
	int ret = 0;
	struct cache_entry *ce_2 = NULL, *ce_3 = NULL;

	/* See if there is such entry in the index. */
	pos = cache_name_pos(path, namelen);
	if (0 <= pos) {
		/* already merged */
		pos = unmerge_cache_entry_at(pos);
		if (pos < active_nr) {
			const struct cache_entry *ce = active_cache[pos];
			if (ce_stage(ce) &&
			    ce_namelen(ce) == namelen &&
			    !memcmp(ce->name, path, namelen))
				return 0;
		}
		/* no resolve-undo information; fall back */
	} else {
		/* If there isn't, either it is unmerged, or
		 * resolved as "removed" by mistake.  We do not
		 * want to do anything in the former case.
		 */
		pos = -pos-1;
		if (pos < active_nr) {
			const struct cache_entry *ce = active_cache[pos];
			if (ce_namelen(ce) == namelen &&
			    !memcmp(ce->name, path, namelen)) {
				fprintf(stderr,
					"%s: skipping still unmerged path.\n",
					path);
				goto free_return;
			}
		}
	}

	/* Grab blobs from given path from HEAD and MERGE_HEAD,
	 * stuff HEAD version in stage #2,
	 * stuff MERGE_HEAD version in stage #3.
	 */
	ce_2 = read_one_ent("our", &head_oid, path, namelen, 2);
	ce_3 = read_one_ent("their", &merge_head_oid, path, namelen, 3);

	if (!ce_2 || !ce_3) {
		ret = -1;
		goto free_return;
	}
	if (oideq(&ce_2->oid, &ce_3->oid) &&
	    ce_2->ce_mode == ce_3->ce_mode) {
		fprintf(stderr, "%s: identical in both, skipping.\n",
			path);
		goto free_return;
	}

	remove_file_from_cache(path);
	if (add_cache_entry(ce_2, ADD_CACHE_OK_TO_ADD)) {
		error("%s: cannot add our version to the index.", path);
		ret = -1;
		goto free_return;
	}
	if (!add_cache_entry(ce_3, ADD_CACHE_OK_TO_ADD))
		return 0;
	error("%s: cannot add their version to the index.", path);
	ret = -1;
 free_return:
	discard_cache_entry(ce_2);
	discard_cache_entry(ce_3);
	return ret;
}

static void read_head_pointers(void)
{
	if (read_ref("HEAD", &head_oid))
		die("No HEAD -- no initial commit yet?");
	if (read_ref("MERGE_HEAD", &merge_head_oid)) {
		fprintf(stderr, "Not in the middle of a merge.\n");
		exit(0);
	}
}

static int do_unresolve(int ac, const char **av,
			const char *prefix, int prefix_length)
{
	int i;
	int err = 0;

	/* Read HEAD and MERGE_HEAD; if MERGE_HEAD does not exist, we
	 * are not doing a merge, so exit with success status.
	 */
	read_head_pointers();

	for (i = 1; i < ac; i++) {
		const char *arg = av[i];
		char *p = prefix_path(prefix, prefix_length, arg);
		err |= unresolve_one(p);
		free(p);
	}
	return err;
}

static int do_reupdate(int ac, const char **av,
		       const char *prefix)
{
	/* Read HEAD and run update-index on paths that are
	 * merged and already different between index and HEAD.
	 */
	int pos;
	int has_head = 1;
	struct pathspec pathspec;

	parse_pathspec(&pathspec, 0,
		       PATHSPEC_PREFER_CWD,
		       prefix, av + 1);

	if (read_ref("HEAD", &head_oid))
		/* If there is no HEAD, that means it is an initial
		 * commit.  Update everything in the index.
		 */
		has_head = 0;
 redo:
	for (pos = 0; pos < active_nr; pos++) {
		const struct cache_entry *ce = active_cache[pos];
		struct cache_entry *old = NULL;
		int save_nr;
		char *path;

		if (ce_stage(ce) || !ce_path_match(&the_index, ce, &pathspec, NULL))
			continue;
		if (has_head)
			old = read_one_ent(NULL, &head_oid,
					   ce->name, ce_namelen(ce), 0);
		if (old && ce->ce_mode == old->ce_mode &&
		    oideq(&ce->oid, &old->oid)) {
			discard_cache_entry(old);
			continue; /* unchanged */
		}
		/* Be careful.  The working tree may not have the
		 * path anymore, in which case, under 'allow_remove',
		 * or worse yet 'allow_replace', active_nr may decrease.
		 */
		save_nr = active_nr;
		path = xstrdup(ce->name);
		update_one(path);
		free(path);
		discard_cache_entry(old);
		if (save_nr != active_nr)
			goto redo;
	}
	clear_pathspec(&pathspec);
	return 0;
}

struct refresh_params {
	unsigned int flags;
	int *has_errors;
};

static int refresh(struct refresh_params *o, unsigned int flag)
{
	setup_work_tree();
	read_cache();
	*o->has_errors |= refresh_cache(o->flags | flag);
	return 0;
}

static int refresh_callback(const struct option *opt,
				const char *arg, int unset)
{
	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);
	return refresh(opt->value, 0);
}

static int really_refresh_callback(const struct option *opt,
				const char *arg, int unset)
{
	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);
	return refresh(opt->value, REFRESH_REALLY);
}

static int chmod_callback(const struct option *opt,
				const char *arg, int unset)
{
	char *flip = opt->value;
	BUG_ON_OPT_NEG(unset);
	if ((arg[0] != '-' && arg[0] != '+') || arg[1] != 'x' || arg[2])
		return error("option 'chmod' expects \"+x\" or \"-x\"");
	*flip = arg[0];
	return 0;
}

static int resolve_undo_clear_callback(const struct option *opt,
				const char *arg, int unset)
{
	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);
	resolve_undo_clear();
	return 0;
}

static int parse_new_style_cacheinfo(const char *arg,
				     unsigned int *mode,
				     struct object_id *oid,
				     const char **path)
{
	unsigned long ul;
	char *endp;
	const char *p;

	if (!arg)
		return -1;

	errno = 0;
	ul = strtoul(arg, &endp, 8);
	if (errno || endp == arg || *endp != ',' || (unsigned int) ul != ul)
		return -1; /* not a new-style cacheinfo */
	*mode = ul;
	endp++;
	if (parse_oid_hex(endp, oid, &p) || *p != ',')
		return -1;
	*path = p + 1;
	return 0;
}

static enum parse_opt_result cacheinfo_callback(
	struct parse_opt_ctx_t *ctx, const struct option *opt,
	const char *arg, int unset)
{
	struct object_id oid;
	unsigned int mode;
	const char *path;

	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);

	if (!parse_new_style_cacheinfo(ctx->argv[1], &mode, &oid, &path)) {
		if (add_cacheinfo(mode, &oid, path, 0))
			die("git update-index: --cacheinfo cannot add %s", path);
		ctx->argv++;
		ctx->argc--;
		return 0;
	}
	if (ctx->argc <= 3)
		return error("option 'cacheinfo' expects <mode>,<sha1>,<path>");
	if (strtoul_ui(*++ctx->argv, 8, &mode) ||
	    get_oid_hex(*++ctx->argv, &oid) ||
	    add_cacheinfo(mode, &oid, *++ctx->argv, 0))
		die("git update-index: --cacheinfo cannot add %s", *ctx->argv);
	ctx->argc -= 3;
	return 0;
}

static enum parse_opt_result stdin_cacheinfo_callback(
	struct parse_opt_ctx_t *ctx, const struct option *opt,
	const char *arg, int unset)
{
	int *nul_term_line = opt->value;

	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);

	if (ctx->argc != 1)
		return error("option '%s' must be the last argument", opt->long_name);
	allow_add = allow_replace = allow_remove = 1;
	read_index_info(*nul_term_line);
	return 0;
}

static enum parse_opt_result stdin_callback(
	struct parse_opt_ctx_t *ctx, const struct option *opt,
	const char *arg, int unset)
{
	int *read_from_stdin = opt->value;

	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);

	if (ctx->argc != 1)
		return error("option '%s' must be the last argument", opt->long_name);
	*read_from_stdin = 1;
	return 0;
}

static enum parse_opt_result unresolve_callback(
	struct parse_opt_ctx_t *ctx, const struct option *opt,
	const char *arg, int unset)
{
	int *has_errors = opt->value;
	const char *prefix = startup_info->prefix;

	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);

	/* consume remaining arguments. */
	*has_errors = do_unresolve(ctx->argc, ctx->argv,
				prefix, prefix ? strlen(prefix) : 0);
	if (*has_errors)
		active_cache_changed = 0;

	ctx->argv += ctx->argc - 1;
	ctx->argc = 1;
	return 0;
}

static enum parse_opt_result reupdate_callback(
	struct parse_opt_ctx_t *ctx, const struct option *opt,
	const char *arg, int unset)
{
	int *has_errors = opt->value;
	const char *prefix = startup_info->prefix;

	BUG_ON_OPT_NEG(unset);
	BUG_ON_OPT_ARG(arg);

	/* consume remaining arguments. */
	setup_work_tree();
	*has_errors = do_reupdate(ctx->argc, ctx->argv, prefix);
	if (*has_errors)
		active_cache_changed = 0;

	ctx->argv += ctx->argc - 1;
	ctx->argc = 1;
	return 0;
}

int cmd_update_index(int argc, const char **argv, const char *prefix)
{
	int newfd, entries, has_errors = 0, nul_term_line = 0;
	enum uc_mode untracked_cache = UC_UNSPECIFIED;
	int read_from_stdin = 0;
	int prefix_length = prefix ? strlen(prefix) : 0;
	int preferred_index_format = 0;
	char set_executable_bit = 0;
	struct refresh_params refresh_args = {0, &has_errors};
	int lock_error = 0;
	int split_index = -1;
	int force_write = 0;
	int fsmonitor = -1;
	struct lock_file lock_file = LOCK_INIT;
	struct parse_opt_ctx_t ctx;
	strbuf_getline_fn getline_fn;
	int parseopt_state = PARSE_OPT_UNKNOWN;
	struct option options[] = {
		OPT_BIT('q', NULL, &refresh_args.flags,
			N_("continue refresh even when index needs update"),
			REFRESH_QUIET),
		OPT_BIT(0, "ignore-submodules", &refresh_args.flags,
			N_("refresh: ignore submodules"),
			REFRESH_IGNORE_SUBMODULES),
		OPT_SET_INT(0, "add", &allow_add,
			N_("do not ignore new files"), 1),
		OPT_SET_INT(0, "replace", &allow_replace,
			N_("let files replace directories and vice-versa"), 1),
		OPT_SET_INT(0, "remove", &allow_remove,
			N_("notice files missing from worktree"), 1),
		OPT_BIT(0, "unmerged", &refresh_args.flags,
			N_("refresh even if index contains unmerged entries"),
			REFRESH_UNMERGED),
		{OPTION_CALLBACK, 0, "refresh", &refresh_args, NULL,
			N_("refresh stat information"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
			refresh_callback},
		{OPTION_CALLBACK, 0, "really-refresh", &refresh_args, NULL,
			N_("like --refresh, but ignore assume-unchanged setting"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
			really_refresh_callback},
		{OPTION_LOWLEVEL_CALLBACK, 0, "cacheinfo", NULL,
			N_("<mode>,<object>,<path>"),
			N_("add the specified entry to the index"),
			PARSE_OPT_NOARG | /* disallow --cacheinfo=<mode> form */
			PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP,
			NULL, 0,
			cacheinfo_callback},
		{OPTION_CALLBACK, 0, "chmod", &set_executable_bit, "(+|-)x",
			N_("override the executable bit of the listed files"),
			PARSE_OPT_NONEG,
			chmod_callback},
		{OPTION_SET_INT, 0, "assume-unchanged", &mark_valid_only, NULL,
			N_("mark files as \"not changing\""),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
		{OPTION_SET_INT, 0, "no-assume-unchanged", &mark_valid_only, NULL,
			N_("clear assumed-unchanged bit"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
		{OPTION_SET_INT, 0, "skip-worktree", &mark_skip_worktree_only, NULL,
			N_("mark files as \"index-only\""),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
		{OPTION_SET_INT, 0, "no-skip-worktree", &mark_skip_worktree_only, NULL,
			N_("clear skip-worktree bit"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
		OPT_SET_INT(0, "info-only", &info_only,
			N_("add to index only; do not add content to object database"), 1),
		OPT_SET_INT(0, "force-remove", &force_remove,
			N_("remove named paths even if present in worktree"), 1),
		OPT_BOOL('z', NULL, &nul_term_line,
			 N_("with --stdin: input lines are terminated by null bytes")),
		{OPTION_LOWLEVEL_CALLBACK, 0, "stdin", &read_from_stdin, NULL,
			N_("read list of paths to be updated from standard input"),
			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
			NULL, 0, stdin_callback},
		{OPTION_LOWLEVEL_CALLBACK, 0, "index-info", &nul_term_line, NULL,
			N_("add entries from standard input to the index"),
			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
			NULL, 0, stdin_cacheinfo_callback},
		{OPTION_LOWLEVEL_CALLBACK, 0, "unresolve", &has_errors, NULL,
			N_("repopulate stages #2 and #3 for the listed paths"),
			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
			NULL, 0, unresolve_callback},
		{OPTION_LOWLEVEL_CALLBACK, 'g', "again", &has_errors, NULL,
			N_("only update entries that differ from HEAD"),
			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
			NULL, 0, reupdate_callback},
		OPT_BIT(0, "ignore-missing", &refresh_args.flags,
			N_("ignore files missing from worktree"),
			REFRESH_IGNORE_MISSING),
		OPT_SET_INT(0, "verbose", &verbose,
			N_("report actions to standard output"), 1),
		{OPTION_CALLBACK, 0, "clear-resolve-undo", NULL, NULL,
			N_("(for porcelains) forget saved unresolved conflicts"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
			resolve_undo_clear_callback},
		OPT_INTEGER(0, "index-version", &preferred_index_format,
			N_("write index in this format")),
		OPT_BOOL(0, "split-index", &split_index,
			N_("enable or disable split index")),
		OPT_BOOL(0, "untracked-cache", &untracked_cache,
			N_("enable/disable untracked cache")),
		OPT_SET_INT(0, "test-untracked-cache", &untracked_cache,
			    N_("test if the filesystem supports untracked cache"), UC_TEST),
		OPT_SET_INT(0, "force-untracked-cache", &untracked_cache,
			    N_("enable untracked cache without testing the filesystem"), UC_FORCE),
		OPT_SET_INT(0, "force-write-index", &force_write,
			N_("write out the index even if is not flagged as changed"), 1),
		OPT_BOOL(0, "fsmonitor", &fsmonitor,
			N_("enable or disable file system monitor")),
		{OPTION_SET_INT, 0, "fsmonitor-valid", &mark_fsmonitor_only, NULL,
			N_("mark files as fsmonitor valid"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
		{OPTION_SET_INT, 0, "no-fsmonitor-valid", &mark_fsmonitor_only, NULL,
			N_("clear fsmonitor valid bit"),
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
		OPT_END()
	};

	if (argc == 2 && !strcmp(argv[1], "-h"))
		usage_with_options(update_index_usage, options);

	git_config(git_default_config, NULL);

	/* we will diagnose later if it turns out that we need to update it */
	newfd = hold_locked_index(&lock_file, 0);
	if (newfd < 0)
		lock_error = errno;

	entries = read_cache();
	if (entries < 0)
		die("cache corrupted");

	the_index.updated_skipworktree = 1;

	/*
	 * Custom copy of parse_options() because we want to handle
	 * filename arguments as they come.
	 */
	parse_options_start(&ctx, argc, argv, prefix,
			    options, PARSE_OPT_STOP_AT_NON_OPTION);
	while (ctx.argc) {
		if (parseopt_state != PARSE_OPT_DONE)
			parseopt_state = parse_options_step(&ctx, options,
							    update_index_usage);
		if (!ctx.argc)
			break;
		switch (parseopt_state) {
		case PARSE_OPT_HELP:
		case PARSE_OPT_ERROR:
			exit(129);
		case PARSE_OPT_COMPLETE:
			exit(0);
		case PARSE_OPT_NON_OPTION:
		case PARSE_OPT_DONE:
		{
			const char *path = ctx.argv[0];
			char *p;

			setup_work_tree();
			p = prefix_path(prefix, prefix_length, path);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free(p);
			ctx.argc--;
			ctx.argv++;
			break;
		}
		case PARSE_OPT_UNKNOWN:
			if (ctx.argv[0][1] == '-')
				error("unknown option '%s'", ctx.argv[0] + 2);
			else
				error("unknown switch '%c'", *ctx.opt);
			usage_with_options(update_index_usage, options);
		}
	}
	argc = parse_options_end(&ctx);

	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
	if (preferred_index_format) {
		if (preferred_index_format < INDEX_FORMAT_LB ||
		    INDEX_FORMAT_UB < preferred_index_format)
			die("index-version %d not in range: %d..%d",
			    preferred_index_format,
			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);

		if (the_index.version != preferred_index_format)
			active_cache_changed |= SOMETHING_CHANGED;
		the_index.version = preferred_index_format;
	}

	if (read_from_stdin) {
		struct strbuf buf = STRBUF_INIT;
		struct strbuf unquoted = STRBUF_INIT;

		setup_work_tree();
		while (getline_fn(&buf, stdin) != EOF) {
			char *p;
			if (!nul_term_line && buf.buf[0] == '"') {
				strbuf_reset(&unquoted);
				if (unquote_c_style(&unquoted, buf.buf, NULL))
					die("line is badly quoted");
				strbuf_swap(&buf, &unquoted);
			}
			p = prefix_path(prefix, prefix_length, buf.buf);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free(p);
		}
		strbuf_release(&unquoted);
		strbuf_release(&buf);
	}

	if (split_index > 0) {
		if (git_config_get_split_index() == 0)
			warning(_("core.splitIndex is set to false; "
				  "remove or change it, if you really want to "
				  "enable split index"));
		if (the_index.split_index)
			the_index.cache_changed |= SPLIT_INDEX_ORDERED;
		else
			add_split_index(&the_index);
	} else if (!split_index) {
		if (git_config_get_split_index() == 1)
			warning(_("core.splitIndex is set to true; "
				  "remove or change it, if you really want to "
				  "disable split index"));
		remove_split_index(&the_index);
	}

	switch (untracked_cache) {
	case UC_UNSPECIFIED:
		break;
	case UC_DISABLE:
		if (git_config_get_untracked_cache() == 1)
			warning(_("core.untrackedCache is set to true; "
				  "remove or change it, if you really want to "
				  "disable the untracked cache"));
		remove_untracked_cache(&the_index);
		report(_("Untracked cache disabled"));
		break;
	case UC_TEST:
		setup_work_tree();
		return !test_if_untracked_cache_is_supported();
	case UC_ENABLE:
	case UC_FORCE:
		if (git_config_get_untracked_cache() == 0)
			warning(_("core.untrackedCache is set to false; "
				  "remove or change it, if you really want to "
				  "enable the untracked cache"));
		add_untracked_cache(&the_index);
		report(_("Untracked cache enabled for '%s'"), get_git_work_tree());
		break;
	default:
		BUG("bad untracked_cache value: %d", untracked_cache);
	}

	if (fsmonitor > 0) {
		if (git_config_get_fsmonitor() == 0)
			warning(_("core.fsmonitor is unset; "
				"set it if you really want to "
				"enable fsmonitor"));
		add_fsmonitor(&the_index);
		report(_("fsmonitor enabled"));
	} else if (!fsmonitor) {
		if (git_config_get_fsmonitor() == 1)
			warning(_("core.fsmonitor is set; "
				"remove it if you really want to "
				"disable fsmonitor"));
		remove_fsmonitor(&the_index);
		report(_("fsmonitor disabled"));
	}

	if (active_cache_changed || force_write) {
		if (newfd < 0) {
			if (refresh_args.flags & REFRESH_QUIET)
				exit(128);
			unable_to_lock_die(get_index_file(), lock_error);
		}
		if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
			die("Unable to write new index file");
	}

	rollback_lock_file(&lock_file);

	return has_errors ? 1 : 0;
}