Git 2.14.1
[git] / builtin / gc.c
1 /*
2  * git gc builtin command
3  *
4  * Cleanup unreachable files and optimize the repository.
5  *
6  * Copyright (c) 2007 James Bowes
7  *
8  * Based on git-gc.sh, which is
9  *
10  * Copyright (c) 2006 Shawn O. Pearce
11  */
12
13 #include "builtin.h"
14 #include "config.h"
15 #include "tempfile.h"
16 #include "lockfile.h"
17 #include "parse-options.h"
18 #include "run-command.h"
19 #include "sigchain.h"
20 #include "argv-array.h"
21 #include "commit.h"
22
23 #define FAILED_RUN "failed to run %s"
24
25 static const char * const builtin_gc_usage[] = {
26         N_("git gc [<options>]"),
27         NULL
28 };
29
30 static int pack_refs = 1;
31 static int prune_reflogs = 1;
32 static int aggressive_depth = 50;
33 static int aggressive_window = 250;
34 static int gc_auto_threshold = 6700;
35 static int gc_auto_pack_limit = 50;
36 static int detach_auto = 1;
37 static timestamp_t gc_log_expire_time;
38 static const char *gc_log_expire = "1.day.ago";
39 static const char *prune_expire = "2.weeks.ago";
40 static const char *prune_worktrees_expire = "3.months.ago";
41
42 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
43 static struct argv_array reflog = ARGV_ARRAY_INIT;
44 static struct argv_array repack = ARGV_ARRAY_INIT;
45 static struct argv_array prune = ARGV_ARRAY_INIT;
46 static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
47 static struct argv_array rerere = ARGV_ARRAY_INIT;
48
49 static struct tempfile pidfile;
50 static struct lock_file log_lock;
51
52 static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
53
54 static void clean_pack_garbage(void)
55 {
56         int i;
57         for (i = 0; i < pack_garbage.nr; i++)
58                 unlink_or_warn(pack_garbage.items[i].string);
59         string_list_clear(&pack_garbage, 0);
60 }
61
62 static void report_pack_garbage(unsigned seen_bits, const char *path)
63 {
64         if (seen_bits == PACKDIR_FILE_IDX)
65                 string_list_append(&pack_garbage, path);
66 }
67
68 static void process_log_file(void)
69 {
70         struct stat st;
71         if (fstat(get_lock_file_fd(&log_lock), &st)) {
72                 /*
73                  * Perhaps there was an i/o error or another
74                  * unlikely situation.  Try to make a note of
75                  * this in gc.log along with any existing
76                  * messages.
77                  */
78                 int saved_errno = errno;
79                 fprintf(stderr, _("Failed to fstat %s: %s"),
80                         get_tempfile_path(&log_lock.tempfile),
81                         strerror(saved_errno));
82                 fflush(stderr);
83                 commit_lock_file(&log_lock);
84                 errno = saved_errno;
85         } else if (st.st_size) {
86                 /* There was some error recorded in the lock file */
87                 commit_lock_file(&log_lock);
88         } else {
89                 /* No error, clean up any old gc.log */
90                 unlink(git_path("gc.log"));
91                 rollback_lock_file(&log_lock);
92         }
93 }
94
95 static void process_log_file_at_exit(void)
96 {
97         fflush(stderr);
98         process_log_file();
99 }
100
101 static void process_log_file_on_signal(int signo)
102 {
103         process_log_file();
104         sigchain_pop(signo);
105         raise(signo);
106 }
107
108 static void gc_config(void)
109 {
110         const char *value;
111
112         if (!git_config_get_value("gc.packrefs", &value)) {
113                 if (value && !strcmp(value, "notbare"))
114                         pack_refs = -1;
115                 else
116                         pack_refs = git_config_bool("gc.packrefs", value);
117         }
118
119         git_config_get_int("gc.aggressivewindow", &aggressive_window);
120         git_config_get_int("gc.aggressivedepth", &aggressive_depth);
121         git_config_get_int("gc.auto", &gc_auto_threshold);
122         git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
123         git_config_get_bool("gc.autodetach", &detach_auto);
124         git_config_get_expiry("gc.pruneexpire", &prune_expire);
125         git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
126         git_config_get_expiry("gc.logexpiry", &gc_log_expire);
127
128         git_config(git_default_config, NULL);
129 }
130
131 static int too_many_loose_objects(void)
132 {
133         /*
134          * Quickly check if a "gc" is needed, by estimating how
135          * many loose objects there are.  Because SHA-1 is evenly
136          * distributed, we can check only one and get a reasonable
137          * estimate.
138          */
139         DIR *dir;
140         struct dirent *ent;
141         int auto_threshold;
142         int num_loose = 0;
143         int needed = 0;
144
145         if (gc_auto_threshold <= 0)
146                 return 0;
147
148         dir = opendir(git_path("objects/17"));
149         if (!dir)
150                 return 0;
151
152         auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
153         while ((ent = readdir(dir)) != NULL) {
154                 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
155                     ent->d_name[38] != '\0')
156                         continue;
157                 if (++num_loose > auto_threshold) {
158                         needed = 1;
159                         break;
160                 }
161         }
162         closedir(dir);
163         return needed;
164 }
165
166 static int too_many_packs(void)
167 {
168         struct packed_git *p;
169         int cnt;
170
171         if (gc_auto_pack_limit <= 0)
172                 return 0;
173
174         prepare_packed_git();
175         for (cnt = 0, p = packed_git; p; p = p->next) {
176                 if (!p->pack_local)
177                         continue;
178                 if (p->pack_keep)
179                         continue;
180                 /*
181                  * Perhaps check the size of the pack and count only
182                  * very small ones here?
183                  */
184                 cnt++;
185         }
186         return gc_auto_pack_limit < cnt;
187 }
188
189 static void add_repack_all_option(void)
190 {
191         if (prune_expire && !strcmp(prune_expire, "now"))
192                 argv_array_push(&repack, "-a");
193         else {
194                 argv_array_push(&repack, "-A");
195                 if (prune_expire)
196                         argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
197         }
198 }
199
200 static void add_repack_incremental_option(void)
201 {
202        argv_array_push(&repack, "--no-write-bitmap-index");
203 }
204
205 static int need_to_gc(void)
206 {
207         /*
208          * Setting gc.auto to 0 or negative can disable the
209          * automatic gc.
210          */
211         if (gc_auto_threshold <= 0)
212                 return 0;
213
214         /*
215          * If there are too many loose objects, but not too many
216          * packs, we run "repack -d -l".  If there are too many packs,
217          * we run "repack -A -d -l".  Otherwise we tell the caller
218          * there is no need.
219          */
220         if (too_many_packs())
221                 add_repack_all_option();
222         else if (too_many_loose_objects())
223                 add_repack_incremental_option();
224         else
225                 return 0;
226
227         if (run_hook_le(NULL, "pre-auto-gc", NULL))
228                 return 0;
229         return 1;
230 }
231
232 /* return NULL on success, else hostname running the gc */
233 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
234 {
235         static struct lock_file lock;
236         char my_host[HOST_NAME_MAX + 1];
237         struct strbuf sb = STRBUF_INIT;
238         struct stat st;
239         uintmax_t pid;
240         FILE *fp;
241         int fd;
242         char *pidfile_path;
243
244         if (is_tempfile_active(&pidfile))
245                 /* already locked */
246                 return NULL;
247
248         if (xgethostname(my_host, sizeof(my_host)))
249                 xsnprintf(my_host, sizeof(my_host), "unknown");
250
251         pidfile_path = git_pathdup("gc.pid");
252         fd = hold_lock_file_for_update(&lock, pidfile_path,
253                                        LOCK_DIE_ON_ERROR);
254         if (!force) {
255                 static char locking_host[HOST_NAME_MAX + 1];
256                 static char *scan_fmt;
257                 int should_exit;
258
259                 if (!scan_fmt)
260                         scan_fmt = xstrfmt("%s %%%dc", "%"SCNuMAX, HOST_NAME_MAX);
261                 fp = fopen(pidfile_path, "r");
262                 memset(locking_host, 0, sizeof(locking_host));
263                 should_exit =
264                         fp != NULL &&
265                         !fstat(fileno(fp), &st) &&
266                         /*
267                          * 12 hour limit is very generous as gc should
268                          * never take that long. On the other hand we
269                          * don't really need a strict limit here,
270                          * running gc --auto one day late is not a big
271                          * problem. --force can be used in manual gc
272                          * after the user verifies that no gc is
273                          * running.
274                          */
275                         time(NULL) - st.st_mtime <= 12 * 3600 &&
276                         fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
277                         /* be gentle to concurrent "gc" on remote hosts */
278                         (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
279                 if (fp != NULL)
280                         fclose(fp);
281                 if (should_exit) {
282                         if (fd >= 0)
283                                 rollback_lock_file(&lock);
284                         *ret_pid = pid;
285                         free(pidfile_path);
286                         return locking_host;
287                 }
288         }
289
290         strbuf_addf(&sb, "%"PRIuMAX" %s",
291                     (uintmax_t) getpid(), my_host);
292         write_in_full(fd, sb.buf, sb.len);
293         strbuf_release(&sb);
294         commit_lock_file(&lock);
295         register_tempfile(&pidfile, pidfile_path);
296         free(pidfile_path);
297         return NULL;
298 }
299
300 static int report_last_gc_error(void)
301 {
302         struct strbuf sb = STRBUF_INIT;
303         int ret = 0;
304         struct stat st;
305         char *gc_log_path = git_pathdup("gc.log");
306
307         if (stat(gc_log_path, &st)) {
308                 if (errno == ENOENT)
309                         goto done;
310
311                 ret = error_errno(_("Can't stat %s"), gc_log_path);
312                 goto done;
313         }
314
315         if (st.st_mtime < gc_log_expire_time)
316                 goto done;
317
318         ret = strbuf_read_file(&sb, gc_log_path, 0);
319         if (ret > 0)
320                 ret = error(_("The last gc run reported the following. "
321                                "Please correct the root cause\n"
322                                "and remove %s.\n"
323                                "Automatic cleanup will not be performed "
324                                "until the file is removed.\n\n"
325                                "%s"),
326                             gc_log_path, sb.buf);
327         strbuf_release(&sb);
328 done:
329         free(gc_log_path);
330         return ret;
331 }
332
333 static int gc_before_repack(void)
334 {
335         if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
336                 return error(FAILED_RUN, pack_refs_cmd.argv[0]);
337
338         if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
339                 return error(FAILED_RUN, reflog.argv[0]);
340
341         pack_refs = 0;
342         prune_reflogs = 0;
343         return 0;
344 }
345
346 int cmd_gc(int argc, const char **argv, const char *prefix)
347 {
348         int aggressive = 0;
349         int auto_gc = 0;
350         int quiet = 0;
351         int force = 0;
352         const char *name;
353         pid_t pid;
354         int daemonized = 0;
355
356         struct option builtin_gc_options[] = {
357                 OPT__QUIET(&quiet, N_("suppress progress reporting")),
358                 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
359                         N_("prune unreferenced objects"),
360                         PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
361                 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
362                 OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
363                 OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
364                 OPT_END()
365         };
366
367         if (argc == 2 && !strcmp(argv[1], "-h"))
368                 usage_with_options(builtin_gc_usage, builtin_gc_options);
369
370         argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
371         argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
372         argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
373         argv_array_pushl(&prune, "prune", "--expire", NULL);
374         argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
375         argv_array_pushl(&rerere, "rerere", "gc", NULL);
376
377         /* default expiry time, overwritten in gc_config */
378         gc_config();
379         if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
380                 die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
381
382         if (pack_refs < 0)
383                 pack_refs = !is_bare_repository();
384
385         argc = parse_options(argc, argv, prefix, builtin_gc_options,
386                              builtin_gc_usage, 0);
387         if (argc > 0)
388                 usage_with_options(builtin_gc_usage, builtin_gc_options);
389
390         if (aggressive) {
391                 argv_array_push(&repack, "-f");
392                 if (aggressive_depth > 0)
393                         argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
394                 if (aggressive_window > 0)
395                         argv_array_pushf(&repack, "--window=%d", aggressive_window);
396         }
397         if (quiet)
398                 argv_array_push(&repack, "-q");
399
400         if (auto_gc) {
401                 /*
402                  * Auto-gc should be least intrusive as possible.
403                  */
404                 if (!need_to_gc())
405                         return 0;
406                 if (!quiet) {
407                         if (detach_auto)
408                                 fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
409                         else
410                                 fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
411                         fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
412                 }
413                 if (detach_auto) {
414                         if (report_last_gc_error())
415                                 return -1;
416
417                         if (lock_repo_for_gc(force, &pid))
418                                 return 0;
419                         if (gc_before_repack())
420                                 return -1;
421                         delete_tempfile(&pidfile);
422
423                         /*
424                          * failure to daemonize is ok, we'll continue
425                          * in foreground
426                          */
427                         daemonized = !daemonize();
428                 }
429         } else
430                 add_repack_all_option();
431
432         name = lock_repo_for_gc(force, &pid);
433         if (name) {
434                 if (auto_gc)
435                         return 0; /* be quiet on --auto */
436                 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
437                     name, (uintmax_t)pid);
438         }
439
440         if (daemonized) {
441                 hold_lock_file_for_update(&log_lock,
442                                           git_path("gc.log"),
443                                           LOCK_DIE_ON_ERROR);
444                 dup2(get_lock_file_fd(&log_lock), 2);
445                 sigchain_push_common(process_log_file_on_signal);
446                 atexit(process_log_file_at_exit);
447         }
448
449         if (gc_before_repack())
450                 return -1;
451
452         if (!repository_format_precious_objects) {
453                 if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
454                         return error(FAILED_RUN, repack.argv[0]);
455
456                 if (prune_expire) {
457                         argv_array_push(&prune, prune_expire);
458                         if (quiet)
459                                 argv_array_push(&prune, "--no-progress");
460                         if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
461                                 return error(FAILED_RUN, prune.argv[0]);
462                 }
463         }
464
465         if (prune_worktrees_expire) {
466                 argv_array_push(&prune_worktrees, prune_worktrees_expire);
467                 if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
468                         return error(FAILED_RUN, prune_worktrees.argv[0]);
469         }
470
471         if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
472                 return error(FAILED_RUN, rerere.argv[0]);
473
474         report_garbage = report_pack_garbage;
475         reprepare_packed_git();
476         if (pack_garbage.nr > 0)
477                 clean_pack_garbage();
478
479         if (auto_gc && too_many_loose_objects())
480                 warning(_("There are too many unreachable loose objects; "
481                         "run 'git prune' to remove them."));
482
483         if (!daemonized)
484                 unlink(git_path("gc.log"));
485
486         return 0;
487 }