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