aboutsummaryrefslogtreecommitdiff
path: root/update-cache.c
blob: 1fcc59a9c005e154c09731f25b7a99389dca2733 (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
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.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-cache *" and suddenly having all the object
 * files be revision controlled.
 */
static int allow_add = 0, allow_remove = 0, allow_replace = 0, not_new = 0, quiet = 0, info_only = 0;
static int force_remove;

/* Three functions to allow overloaded pointer return; see linux/err.h */
static inline void *ERR_PTR(long error)
{
	return (void *) error;
}

static inline long PTR_ERR(const void *ptr)
{
	return (long) ptr;
}

static inline long IS_ERR(const void *ptr)
{
	return (unsigned long)ptr > (unsigned long)-1000L;
}

static int add_file_to_cache(char *path)
{
	int size, namelen, option, status;
	struct cache_entry *ce;
	struct stat st;
	int fd;
	char *target;

	status = lstat(path, &st);
	if (status < 0 || S_ISDIR(st.st_mode)) {
		/* When we used to have "path" and now we want to add
		 * "path/file", we need a way to remove "path" before
		 * being able to add "path/file".  However,
		 * "git-update-cache --remove path" would not work.
		 * --force-remove can be used but this is more user
		 * friendly, especially since we can do the opposite
		 * case just fine without --force-remove.
		 */
		if (status == 0 || (errno == ENOENT || errno == ENOTDIR)) {
			if (allow_remove)
				return remove_file_from_cache(path);
		}
		return error("open(\"%s\"): %s", path, strerror(errno));
	}
	namelen = strlen(path);
	size = cache_entry_size(namelen);
	ce = xmalloc(size);
	memset(ce, 0, size);
	memcpy(ce->name, path, namelen);
	fill_stat_cache_info(ce, &st);
	ce->ce_mode = create_ce_mode(st.st_mode);
	ce->ce_flags = htons(namelen);
	switch (st.st_mode & S_IFMT) {
	case S_IFREG:
		fd = open(path, O_RDONLY);
		if (fd < 0)
			return -1;
		if (index_fd(ce->sha1, fd, &st, !info_only, NULL) < 0)
			return -1;
		break;
	case S_IFLNK:
		target = xmalloc(st.st_size+1);
		if (readlink(path, target, st.st_size+1) != st.st_size) {
			free(target);
			return -1;
		}
		if (info_only) {
			unsigned char hdr[50];
			int hdrlen;
			write_sha1_file_prepare(target, st.st_size, "blob",
						ce->sha1, hdr, &hdrlen);
		} else if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
			return -1;
		free(target);
		break;
	default:
		return -1;
	}
	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
	return add_cache_entry(ce, option);
}

static int compare_data(struct cache_entry *ce, struct stat *st)
{
	int match = -1;
	int fd = open(ce->name, O_RDONLY);

	if (fd >= 0) {
		unsigned char sha1[20];
		if (!index_fd(sha1, fd, st, 0, NULL))
			match = memcmp(sha1, ce->sha1, 20);
		close(fd);
	}
	return match;
}

static int compare_link(struct cache_entry *ce, unsigned long expected_size)
{
	int match = -1;
	char *target;
	void *buffer;
	unsigned long size;
	char type[10];
	int len;

	target = xmalloc(expected_size);
	len = readlink(ce->name, target, expected_size);
	if (len != expected_size) {
		free(target);
		return -1;
	}
	buffer = read_sha1_file(ce->sha1, type, &size);
	if (!buffer) {
		free(target);
		return -1;
	}
	if (size == expected_size)
		match = memcmp(buffer, target, size);
	free(buffer);
	free(target);
	return match;
}

/*
 * "refresh" does not calculate a new sha1 file or bring the
 * cache up-to-date for mode/content changes. But what it
 * _does_ do is to "re-match" the stat information of a file
 * with the cache, so that you can refresh the cache for a
 * file that hasn't been changed but where the stat entry is
 * out of date.
 *
 * For example, you'd want to do this after doing a "git-read-tree",
 * to link up the stat cache details with the proper files.
 */
static struct cache_entry *refresh_entry(struct cache_entry *ce)
{
	struct stat st;
	struct cache_entry *updated;
	int changed, size;

	if (lstat(ce->name, &st) < 0)
		return ERR_PTR(-errno);

	changed = ce_match_stat(ce, &st);
	if (!changed)
		return ce;

	/*
	 * If the mode or type has changed, there's no point in trying
	 * to refresh the entry - it's not going to match
	 */
	if (changed & (MODE_CHANGED | TYPE_CHANGED))
		return ERR_PTR(-EINVAL);

	switch (st.st_mode & S_IFMT) {
	case S_IFREG:
		if (compare_data(ce, &st))
			return ERR_PTR(-EINVAL);
		break;
	case S_IFLNK:
		if (compare_link(ce, st.st_size))
			return ERR_PTR(-EINVAL);
		break;
	default:
		return ERR_PTR(-EINVAL);
	}

	size = ce_size(ce);
	updated = xmalloc(size);
	memcpy(updated, ce, size);
	fill_stat_cache_info(updated, &st);
	return updated;
}

static int refresh_cache(void)
{
	int i;
	int has_errors = 0;

	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce, *new;
		ce = active_cache[i];
		if (ce_stage(ce)) {
			printf("%s: needs merge\n", ce->name);
			has_errors = 1;
			while ((i < active_nr) &&
			       ! strcmp(active_cache[i]->name, ce->name))
				i++;
			i--;
			continue;
		}

		new = refresh_entry(ce);
		if (IS_ERR(new)) {
			if (not_new && PTR_ERR(new) == -ENOENT)
				continue;
			if (quiet)
				continue;
			printf("%s: needs update\n", ce->name);
			has_errors = 1;
			continue;
		}
		active_cache_changed = 1;
		/* You can NOT just free active_cache[i] here, since it
		 * might not be necessarily malloc()ed but can also come
		 * from mmap(). */
		active_cache[i] = new;
	}
	return has_errors;
}

/*
 * We fundamentally don't like some paths: we don't want
 * dot or dot-dot anywhere, and for obvious reasons don't
 * want to recurse into ".git" either.
 *
 * Also, we don't want double slashes or slashes at the
 * end that can make pathnames ambiguous.
 */
static int verify_dotfile(const char *rest)
{
	/*
	 * The first character was '.', but that
	 * has already been discarded, we now test
	 * the rest.
	 */
	switch (*rest) {
	/* "." is not allowed */
	case '\0': case '/':
		return 0;

	/*
	 * ".git" followed by  NUL or slash is bad. This
	 * shares the path end test with the ".." case.
	 */
	case 'g':
		if (rest[1] != 'i')
			break;
		if (rest[2] != 't')
			break;
		rest += 2;
	/* fallthrough */
	case '.':
		if (rest[1] == '\0' || rest[1] == '/')
			return 0;
	}
	return 1;
}

static int verify_path(char *path)
{
	char c;

	goto inside;
	for (;;) {
		if (!c)
			return 1;
		if (c == '/') {
inside:
			c = *path++;
			switch (c) {
			default:
				continue;
			case '/': case '\0':
				break;
			case '.':
				if (verify_dotfile(path))
					continue;
			}
			return 0;
		}
		c = *path++;
	}
}

static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
{
	int size, len, option;
	unsigned int mode;
	unsigned char sha1[20];
	struct cache_entry *ce;

	if (sscanf(arg1, "%o", &mode) != 1)
		return -1;
	if (get_sha1_hex(arg2, sha1))
		return -1;
	if (!verify_path(arg3))
		return -1;

	len = strlen(arg3);
	size = cache_entry_size(len);
	ce = xmalloc(size);
	memset(ce, 0, size);

	memcpy(ce->sha1, sha1, 20);
	memcpy(ce->name, arg3, len);
	ce->ce_flags = htons(len);
	ce->ce_mode = create_ce_mode(mode);
	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
	return add_cache_entry(ce, option);
}

static struct cache_file cache_file;

int main(int argc, char **argv)
{
	int i, newfd, entries, has_errors = 0;
	int allow_options = 1;

	newfd = hold_index_file_for_update(&cache_file, get_index_file());
	if (newfd < 0)
		die("unable to create new cachefile");

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

	for (i = 1 ; i < argc; i++) {
		char *path = argv[i];

		if (allow_options && *path == '-') {
			if (!strcmp(path, "--")) {
				allow_options = 0;
				continue;
			}
			if (!strcmp(path, "-q")) {
				quiet = 1;
				continue;
			}
			if (!strcmp(path, "--add")) {
				allow_add = 1;
				continue;
			}
			if (!strcmp(path, "--replace")) {
				allow_replace = 1;
				continue;
			}
			if (!strcmp(path, "--remove")) {
				allow_remove = 1;
				continue;
			}
			if (!strcmp(path, "--refresh")) {
				has_errors |= refresh_cache();
				continue;
			}
			if (!strcmp(path, "--cacheinfo")) {
				if (i+3 >= argc)
					die("git-update-cache: --cacheinfo <mode> <sha1> <path>");
				if (add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
					die("git-update-cache: --cacheinfo cannot add %s", argv[i+3]);
				i += 3;
				continue;
			}
			if (!strcmp(path, "--info-only")) {
				info_only = 1;
				continue;
			}
			if (!strcmp(path, "--force-remove")) {
				force_remove = 1;
				continue;
			}

			if (!strcmp(path, "--ignore-missing")) {
				not_new = 1;
				continue;
			}
			die("unknown option %s", path);
		}
		if (!verify_path(path)) {
			fprintf(stderr, "Ignoring path %s\n", argv[i]);
			continue;
		}
		if (force_remove) {
			if (remove_file_from_cache(path))
				die("git-update-cache: --force-remove cannot remove %s", path);
			continue;
		}
		if (add_file_to_cache(path))
			die("Unable to add %s to database", path);
	}
	if (write_cache(newfd, active_cache, active_nr) ||
	    commit_index_file(&cache_file))
		die("Unable to write new cachefile");

	return has_errors ? 1 : 0;
}