summaryrefslogtreecommitdiffstats
path: root/tmp-objdir.c
blob: 3509258be53644973ca2b2b04cc0ec5b27ea96c6 (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
#include "git-compat-util.h"
#include "tmp-objdir.h"
#include "abspath.h"
#include "chdir-notify.h"
#include "dir.h"
#include "environment.h"
#include "object-file.h"
#include "path.h"
#include "string-list.h"
#include "strbuf.h"
#include "strvec.h"
#include "quote.h"
#include "object-store-ll.h"

struct tmp_objdir {
	struct strbuf path;
	struct strvec env;
	struct object_directory *prev_odb;
	int will_destroy;
};

/*
 * Allow only one tmp_objdir at a time in a running process, which simplifies
 * our atexit cleanup routines.  It's doubtful callers will ever need
 * more than one, and we can expand later if so.  You can have many such
 * tmp_objdirs simultaneously in many processes, of course.
 */
static struct tmp_objdir *the_tmp_objdir;

static void tmp_objdir_free(struct tmp_objdir *t)
{
	strbuf_release(&t->path);
	strvec_clear(&t->env);
	free(t);
}

int tmp_objdir_destroy(struct tmp_objdir *t)
{
	int err;

	if (!t)
		return 0;

	if (t == the_tmp_objdir)
		the_tmp_objdir = NULL;

	if (t->prev_odb)
		restore_primary_odb(t->prev_odb, t->path.buf);

	err = remove_dir_recursively(&t->path, 0);

	tmp_objdir_free(t);

	return err;
}

static void remove_tmp_objdir(void)
{
	tmp_objdir_destroy(the_tmp_objdir);
}

void tmp_objdir_discard_objects(struct tmp_objdir *t)
{
	remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL);
}

/*
 * These env_* functions are for setting up the child environment; the
 * "replace" variant overrides the value of any existing variable with that
 * "key". The "append" variant puts our new value at the end of a list,
 * separated by PATH_SEP (which is what separate values in
 * GIT_ALTERNATE_OBJECT_DIRECTORIES).
 */
static void env_append(struct strvec *env, const char *key, const char *val)
{
	struct strbuf quoted = STRBUF_INIT;
	const char *old;

	/*
	 * Avoid quoting if it's not necessary, for maximum compatibility
	 * with older parsers which don't understand the quoting.
	 */
	if (*val == '"' || strchr(val, PATH_SEP)) {
		strbuf_addch(&quoted, '"');
		quote_c_style(val, &quoted, NULL, 1);
		strbuf_addch(&quoted, '"');
		val = quoted.buf;
	}

	old = getenv(key);
	if (!old)
		strvec_pushf(env, "%s=%s", key, val);
	else
		strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);

	strbuf_release(&quoted);
}

static void env_replace(struct strvec *env, const char *key, const char *val)
{
	strvec_pushf(env, "%s=%s", key, val);
}

static int setup_tmp_objdir(const char *root)
{
	char *path;
	int ret = 0;

	path = xstrfmt("%s/pack", root);
	ret = mkdir(path, 0777);
	free(path);

	return ret;
}

struct tmp_objdir *tmp_objdir_create(const char *prefix)
{
	static int installed_handlers;
	struct tmp_objdir *t;

	if (the_tmp_objdir)
		BUG("only one tmp_objdir can be used at a time");

	t = xcalloc(1, sizeof(*t));
	strbuf_init(&t->path, 0);
	strvec_init(&t->env);

	/*
	 * Use a string starting with tmp_ so that the builtin/prune.c code
	 * can recognize any stale objdirs left behind by a crash and delete
	 * them.
	 */
	strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX", get_object_directory(), prefix);

	if (!mkdtemp(t->path.buf)) {
		/* free, not destroy, as we never touched the filesystem */
		tmp_objdir_free(t);
		return NULL;
	}

	the_tmp_objdir = t;
	if (!installed_handlers) {
		atexit(remove_tmp_objdir);
		installed_handlers++;
	}

	if (setup_tmp_objdir(t->path.buf)) {
		tmp_objdir_destroy(t);
		return NULL;
	}

	env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
		   absolute_path(get_object_directory()));
	env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
	env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
		    absolute_path(t->path.buf));

	return t;
}

/*
 * Make sure we copy packfiles and their associated metafiles in the correct
 * order. All of these ends_with checks are slightly expensive to do in
 * the midst of a sorting routine, but in practice it shouldn't matter.
 * We will have a relatively small number of packfiles to order, and loose
 * objects exit early in the first line.
 */
static int pack_copy_priority(const char *name)
{
	if (!starts_with(name, "pack"))
		return 0;
	if (ends_with(name, ".keep"))
		return 1;
	if (ends_with(name, ".pack"))
		return 2;
	if (ends_with(name, ".rev"))
		return 3;
	if (ends_with(name, ".idx"))
		return 4;
	return 5;
}

static int pack_copy_cmp(const char *a, const char *b)
{
	return pack_copy_priority(a) - pack_copy_priority(b);
}

static int read_dir_paths(struct string_list *out, const char *path)
{
	DIR *dh;
	struct dirent *de;

	dh = opendir(path);
	if (!dh)
		return -1;

	while ((de = readdir(dh)))
		if (de->d_name[0] != '.')
			string_list_append(out, de->d_name);

	closedir(dh);
	return 0;
}

static int migrate_paths(struct strbuf *src, struct strbuf *dst);

static int migrate_one(struct strbuf *src, struct strbuf *dst)
{
	struct stat st;

	if (stat(src->buf, &st) < 0)
		return -1;
	if (S_ISDIR(st.st_mode)) {
		if (!mkdir(dst->buf, 0777)) {
			if (adjust_shared_perm(dst->buf))
				return -1;
		} else if (errno != EEXIST)
			return -1;
		return migrate_paths(src, dst);
	}
	return finalize_object_file(src->buf, dst->buf);
}

static int migrate_paths(struct strbuf *src, struct strbuf *dst)
{
	size_t src_len = src->len, dst_len = dst->len;
	struct string_list paths = STRING_LIST_INIT_DUP;
	int i;
	int ret = 0;

	if (read_dir_paths(&paths, src->buf) < 0)
		return -1;
	paths.cmp = pack_copy_cmp;
	string_list_sort(&paths);

	for (i = 0; i < paths.nr; i++) {
		const char *name = paths.items[i].string;

		strbuf_addf(src, "/%s", name);
		strbuf_addf(dst, "/%s", name);

		ret |= migrate_one(src, dst);

		strbuf_setlen(src, src_len);
		strbuf_setlen(dst, dst_len);
	}

	string_list_clear(&paths, 0);
	return ret;
}

int tmp_objdir_migrate(struct tmp_objdir *t)
{
	struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
	int ret;

	if (!t)
		return 0;

	if (t->prev_odb) {
		if (the_repository->objects->odb->will_destroy)
			BUG("migrating an ODB that was marked for destruction");
		restore_primary_odb(t->prev_odb, t->path.buf);
		t->prev_odb = NULL;
	}

	strbuf_addbuf(&src, &t->path);
	strbuf_addstr(&dst, get_object_directory());

	ret = migrate_paths(&src, &dst);

	strbuf_release(&src);
	strbuf_release(&dst);

	tmp_objdir_destroy(t);
	return ret;
}

const char **tmp_objdir_env(const struct tmp_objdir *t)
{
	if (!t)
		return NULL;
	return t->env.v;
}

void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
{
	add_to_alternates_memory(t->path.buf);
}

void tmp_objdir_replace_primary_odb(struct tmp_objdir *t, int will_destroy)
{
	if (t->prev_odb)
		BUG("the primary object database is already replaced");
	t->prev_odb = set_temporary_primary_odb(t->path.buf, will_destroy);
	t->will_destroy = will_destroy;
}

struct tmp_objdir *tmp_objdir_unapply_primary_odb(void)
{
	if (!the_tmp_objdir || !the_tmp_objdir->prev_odb)
		return NULL;

	restore_primary_odb(the_tmp_objdir->prev_odb, the_tmp_objdir->path.buf);
	the_tmp_objdir->prev_odb = NULL;
	return the_tmp_objdir;
}

void tmp_objdir_reapply_primary_odb(struct tmp_objdir *t, const char *old_cwd,
		const char *new_cwd)
{
	char *path;

	path = reparent_relative_path(old_cwd, new_cwd, t->path.buf);
	strbuf_reset(&t->path);
	strbuf_addstr(&t->path, path);
	free(path);
	tmp_objdir_replace_primary_odb(t, t->will_destroy);
}