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