summaryrefslogtreecommitdiff
path: root/builtin/gc.c
blob: 069950d0b417f5eb97cd756ae32df7a2fb13abce (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
/*
 * git gc builtin command
 *
 * Cleanup unreachable files and optimize the repository.
 *
 * Copyright (c) 2007 James Bowes
 *
 * Based on git-gc.sh, which is
 *
 * Copyright (c) 2006 Shawn O. Pearce
 */

#include "builtin.h"
#include "tempfile.h"
#include "lockfile.h"
#include "parse-options.h"
#include "run-command.h"
#include "sigchain.h"
#include "argv-array.h"
#include "commit.h"

#define FAILED_RUN "failed to run %s"

static const char * const builtin_gc_usage[] = {
	N_("git gc [<options>]"),
	NULL
};

static int pack_refs = 1;
static int prune_reflogs = 1;
static int aggressive_depth = 50;
static int aggressive_window = 250;
static int gc_auto_threshold = 6700;
static int gc_auto_pack_limit = 50;
static int detach_auto = 1;
static const char *prune_expire = "2.weeks.ago";
static const char *prune_worktrees_expire = "3.months.ago";

static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
static struct argv_array reflog = ARGV_ARRAY_INIT;
static struct argv_array repack = ARGV_ARRAY_INIT;
static struct argv_array prune = ARGV_ARRAY_INIT;
static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
static struct argv_array rerere = ARGV_ARRAY_INIT;

static struct tempfile pidfile;
static struct lock_file log_lock;

static struct string_list pack_garbage = STRING_LIST_INIT_DUP;

static void clean_pack_garbage(void)
{
	int i;
	for (i = 0; i < pack_garbage.nr; i++)
		unlink_or_warn(pack_garbage.items[i].string);
	string_list_clear(&pack_garbage, 0);
}

static void report_pack_garbage(unsigned seen_bits, const char *path)
{
	if (seen_bits == PACKDIR_FILE_IDX)
		string_list_append(&pack_garbage, path);
}

static void git_config_date_string(const char *key, const char **output)
{
	if (git_config_get_string_const(key, output))
		return;
	if (strcmp(*output, "now")) {
		unsigned long now = approxidate("now");
		if (approxidate(*output) >= now)
			git_die_config(key, _("Invalid %s: '%s'"), key, *output);
	}
}

static void process_log_file(void)
{
	struct stat st;
	if (!fstat(get_lock_file_fd(&log_lock), &st) && st.st_size)
		commit_lock_file(&log_lock);
	else
		rollback_lock_file(&log_lock);
}

static void process_log_file_at_exit(void)
{
	fflush(stderr);
	process_log_file();
}

static void process_log_file_on_signal(int signo)
{
	process_log_file();
	sigchain_pop(signo);
	raise(signo);
}

static void gc_config(void)
{
	const char *value;

	if (!git_config_get_value("gc.packrefs", &value)) {
		if (value && !strcmp(value, "notbare"))
			pack_refs = -1;
		else
			pack_refs = git_config_bool("gc.packrefs", value);
	}

	git_config_get_int("gc.aggressivewindow", &aggressive_window);
	git_config_get_int("gc.aggressivedepth", &aggressive_depth);
	git_config_get_int("gc.auto", &gc_auto_threshold);
	git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
	git_config_get_bool("gc.autodetach", &detach_auto);
	git_config_date_string("gc.pruneexpire", &prune_expire);
	git_config_date_string("gc.worktreepruneexpire", &prune_worktrees_expire);
	git_config(git_default_config, NULL);
}

static int too_many_loose_objects(void)
{
	/*
	 * Quickly check if a "gc" is needed, by estimating how
	 * many loose objects there are.  Because SHA-1 is evenly
	 * distributed, we can check only one and get a reasonable
	 * estimate.
	 */
	char path[PATH_MAX];
	const char *objdir = get_object_directory();
	DIR *dir;
	struct dirent *ent;
	int auto_threshold;
	int num_loose = 0;
	int needed = 0;

	if (gc_auto_threshold <= 0)
		return 0;

	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
		warning(_("insanely long object directory %.*s"), 50, objdir);
		return 0;
	}
	dir = opendir(path);
	if (!dir)
		return 0;

	auto_threshold = (gc_auto_threshold + 255) / 256;
	while ((ent = readdir(dir)) != NULL) {
		if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
		    ent->d_name[38] != '\0')
			continue;
		if (++num_loose > auto_threshold) {
			needed = 1;
			break;
		}
	}
	closedir(dir);
	return needed;
}

static int too_many_packs(void)
{
	struct packed_git *p;
	int cnt;

	if (gc_auto_pack_limit <= 0)
		return 0;

	prepare_packed_git();
	for (cnt = 0, p = packed_git; p; p = p->next) {
		if (!p->pack_local)
			continue;
		if (p->pack_keep)
			continue;
		/*
		 * Perhaps check the size of the pack and count only
		 * very small ones here?
		 */
		cnt++;
	}
	return gc_auto_pack_limit < cnt;
}

static void add_repack_all_option(void)
{
	if (prune_expire && !strcmp(prune_expire, "now"))
		argv_array_push(&repack, "-a");
	else {
		argv_array_push(&repack, "-A");
		if (prune_expire)
			argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
	}
}

static int need_to_gc(void)
{
	/*
	 * Setting gc.auto to 0 or negative can disable the
	 * automatic gc.
	 */
	if (gc_auto_threshold <= 0)
		return 0;

	/*
	 * If there are too many loose objects, but not too many
	 * packs, we run "repack -d -l".  If there are too many packs,
	 * we run "repack -A -d -l".  Otherwise we tell the caller
	 * there is no need.
	 */
	if (too_many_packs())
		add_repack_all_option();
	else if (!too_many_loose_objects())
		return 0;

	if (run_hook_le(NULL, "pre-auto-gc", NULL))
		return 0;
	return 1;
}

/* return NULL on success, else hostname running the gc */
static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
{
	static struct lock_file lock;
	char my_host[128];
	struct strbuf sb = STRBUF_INIT;
	struct stat st;
	uintmax_t pid;
	FILE *fp;
	int fd;
	char *pidfile_path;

	if (is_tempfile_active(&pidfile))
		/* already locked */
		return NULL;

	if (gethostname(my_host, sizeof(my_host)))
		xsnprintf(my_host, sizeof(my_host), "unknown");

	pidfile_path = git_pathdup("gc.pid");
	fd = hold_lock_file_for_update(&lock, pidfile_path,
				       LOCK_DIE_ON_ERROR);
	if (!force) {
		static char locking_host[128];
		int should_exit;
		fp = fopen(pidfile_path, "r");
		memset(locking_host, 0, sizeof(locking_host));
		should_exit =
			fp != NULL &&
			!fstat(fileno(fp), &st) &&
			/*
			 * 12 hour limit is very generous as gc should
			 * never take that long. On the other hand we
			 * don't really need a strict limit here,
			 * running gc --auto one day late is not a big
			 * problem. --force can be used in manual gc
			 * after the user verifies that no gc is
			 * running.
			 */
			time(NULL) - st.st_mtime <= 12 * 3600 &&
			fscanf(fp, "%"SCNuMAX" %127c", &pid, locking_host) == 2 &&
			/* be gentle to concurrent "gc" on remote hosts */
			(strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
		if (fp != NULL)
			fclose(fp);
		if (should_exit) {
			if (fd >= 0)
				rollback_lock_file(&lock);
			*ret_pid = pid;
			free(pidfile_path);
			return locking_host;
		}
	}

	strbuf_addf(&sb, "%"PRIuMAX" %s",
		    (uintmax_t) getpid(), my_host);
	write_in_full(fd, sb.buf, sb.len);
	strbuf_release(&sb);
	commit_lock_file(&lock);
	register_tempfile(&pidfile, pidfile_path);
	free(pidfile_path);
	return NULL;
}

static int report_last_gc_error(void)
{
	struct strbuf sb = STRBUF_INIT;
	int ret;

	ret = strbuf_read_file(&sb, git_path("gc.log"), 0);
	if (ret > 0)
		return error(_("The last gc run reported the following. "
			       "Please correct the root cause\n"
			       "and remove %s.\n"
			       "Automatic cleanup will not be performed "
			       "until the file is removed.\n\n"
			       "%s"),
			     git_path("gc.log"), sb.buf);
	strbuf_release(&sb);
	return 0;
}

static int gc_before_repack(void)
{
	if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
		return error(FAILED_RUN, pack_refs_cmd.argv[0]);

	if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
		return error(FAILED_RUN, reflog.argv[0]);

	pack_refs = 0;
	prune_reflogs = 0;
	return 0;
}

int cmd_gc(int argc, const char **argv, const char *prefix)
{
	int aggressive = 0;
	int auto_gc = 0;
	int quiet = 0;
	int force = 0;
	const char *name;
	pid_t pid;
	int daemonized = 0;

	struct option builtin_gc_options[] = {
		OPT__QUIET(&quiet, N_("suppress progress reporting")),
		{ OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
			N_("prune unreferenced objects"),
			PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
		OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
		OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
		OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
		OPT_END()
	};

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

	argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
	argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
	argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
	argv_array_pushl(&prune, "prune", "--expire", NULL);
	argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
	argv_array_pushl(&rerere, "rerere", "gc", NULL);

	gc_config();

	if (pack_refs < 0)
		pack_refs = !is_bare_repository();

	argc = parse_options(argc, argv, prefix, builtin_gc_options,
			     builtin_gc_usage, 0);
	if (argc > 0)
		usage_with_options(builtin_gc_usage, builtin_gc_options);

	if (aggressive) {
		argv_array_push(&repack, "-f");
		if (aggressive_depth > 0)
			argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
		if (aggressive_window > 0)
			argv_array_pushf(&repack, "--window=%d", aggressive_window);
	}
	if (quiet)
		argv_array_push(&repack, "-q");

	if (auto_gc) {
		/*
		 * Auto-gc should be least intrusive as possible.
		 */
		if (!need_to_gc())
			return 0;
		if (!quiet) {
			if (detach_auto)
				fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
			else
				fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
			fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
		}
		if (detach_auto) {
			if (report_last_gc_error())
				return -1;

			if (gc_before_repack())
				return -1;
			/*
			 * failure to daemonize is ok, we'll continue
			 * in foreground
			 */
			daemonized = !daemonize();
		}
	} else
		add_repack_all_option();

	name = lock_repo_for_gc(force, &pid);
	if (name) {
		if (auto_gc)
			return 0; /* be quiet on --auto */
		die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
		    name, (uintmax_t)pid);
	}

	if (daemonized) {
		hold_lock_file_for_update(&log_lock,
					  git_path("gc.log"),
					  LOCK_DIE_ON_ERROR);
		dup2(get_lock_file_fd(&log_lock), 2);
		sigchain_push_common(process_log_file_on_signal);
		atexit(process_log_file_at_exit);
	}

	if (gc_before_repack())
		return -1;

	if (!repository_format_precious_objects) {
		if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
			return error(FAILED_RUN, repack.argv[0]);

		if (prune_expire) {
			argv_array_push(&prune, prune_expire);
			if (quiet)
				argv_array_push(&prune, "--no-progress");
			if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
				return error(FAILED_RUN, prune.argv[0]);
		}
	}

	if (prune_worktrees_expire) {
		argv_array_push(&prune_worktrees, prune_worktrees_expire);
		if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
			return error(FAILED_RUN, prune_worktrees.argv[0]);
	}

	if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
		return error(FAILED_RUN, rerere.argv[0]);

	report_garbage = report_pack_garbage;
	reprepare_packed_git();
	if (pack_garbage.nr > 0)
		clean_pack_garbage();

	if (auto_gc && too_many_loose_objects())
		warning(_("There are too many unreachable loose objects; "
			"run 'git prune' to remove them."));

	return 0;
}