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