lockfile.h: extract new header file for the functions in lockfile.c
[git/git.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 "lockfile.h"
15 #include "parse-options.h"
16 #include "run-command.h"
17 #include "sigchain.h"
18 #include "argv-array.h"
19 #include "commit.h"
20
21 #define FAILED_RUN "failed to run %s"
22
23 static const char * const builtin_gc_usage[] = {
24 N_("git gc [options]"),
25 NULL
26 };
27
28 static int pack_refs = 1;
29 static int prune_reflogs = 1;
30 static int aggressive_depth = 250;
31 static int aggressive_window = 250;
32 static int gc_auto_threshold = 6700;
33 static int gc_auto_pack_limit = 50;
34 static int detach_auto = 1;
35 static const char *prune_expire = "2.weeks.ago";
36
37 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
38 static struct argv_array reflog = ARGV_ARRAY_INIT;
39 static struct argv_array repack = ARGV_ARRAY_INIT;
40 static struct argv_array prune = ARGV_ARRAY_INIT;
41 static struct argv_array rerere = ARGV_ARRAY_INIT;
42
43 static char *pidfile;
44
45 static void remove_pidfile(void)
46 {
47 if (pidfile)
48 unlink(pidfile);
49 }
50
51 static void remove_pidfile_on_signal(int signo)
52 {
53 remove_pidfile();
54 sigchain_pop(signo);
55 raise(signo);
56 }
57
58 static void gc_config(void)
59 {
60 const char *value;
61
62 if (!git_config_get_value("gc.packrefs", &value)) {
63 if (value && !strcmp(value, "notbare"))
64 pack_refs = -1;
65 else
66 pack_refs = git_config_bool("gc.packrefs", value);
67 }
68
69 git_config_get_int("gc.aggressivewindow", &aggressive_window);
70 git_config_get_int("gc.aggressivedepth", &aggressive_depth);
71 git_config_get_int("gc.auto", &gc_auto_threshold);
72 git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
73 git_config_get_bool("gc.autodetach", &detach_auto);
74
75 if (!git_config_get_string_const("gc.pruneexpire", &prune_expire)) {
76 if (strcmp(prune_expire, "now")) {
77 unsigned long now = approxidate("now");
78 if (approxidate(prune_expire) >= now) {
79 git_die_config("gc.pruneexpire", _("Invalid gc.pruneexpire: '%s'"),
80 prune_expire);
81 }
82 }
83 }
84 git_config(git_default_config, NULL);
85 }
86
87 static int too_many_loose_objects(void)
88 {
89 /*
90 * Quickly check if a "gc" is needed, by estimating how
91 * many loose objects there are. Because SHA-1 is evenly
92 * distributed, we can check only one and get a reasonable
93 * estimate.
94 */
95 char path[PATH_MAX];
96 const char *objdir = get_object_directory();
97 DIR *dir;
98 struct dirent *ent;
99 int auto_threshold;
100 int num_loose = 0;
101 int needed = 0;
102
103 if (gc_auto_threshold <= 0)
104 return 0;
105
106 if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
107 warning(_("insanely long object directory %.*s"), 50, objdir);
108 return 0;
109 }
110 dir = opendir(path);
111 if (!dir)
112 return 0;
113
114 auto_threshold = (gc_auto_threshold + 255) / 256;
115 while ((ent = readdir(dir)) != NULL) {
116 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
117 ent->d_name[38] != '\0')
118 continue;
119 if (++num_loose > auto_threshold) {
120 needed = 1;
121 break;
122 }
123 }
124 closedir(dir);
125 return needed;
126 }
127
128 static int too_many_packs(void)
129 {
130 struct packed_git *p;
131 int cnt;
132
133 if (gc_auto_pack_limit <= 0)
134 return 0;
135
136 prepare_packed_git();
137 for (cnt = 0, p = packed_git; p; p = p->next) {
138 if (!p->pack_local)
139 continue;
140 if (p->pack_keep)
141 continue;
142 /*
143 * Perhaps check the size of the pack and count only
144 * very small ones here?
145 */
146 cnt++;
147 }
148 return gc_auto_pack_limit <= cnt;
149 }
150
151 static void add_repack_all_option(void)
152 {
153 if (prune_expire && !strcmp(prune_expire, "now"))
154 argv_array_push(&repack, "-a");
155 else {
156 argv_array_push(&repack, "-A");
157 if (prune_expire)
158 argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
159 }
160 }
161
162 static int need_to_gc(void)
163 {
164 /*
165 * Setting gc.auto to 0 or negative can disable the
166 * automatic gc.
167 */
168 if (gc_auto_threshold <= 0)
169 return 0;
170
171 /*
172 * If there are too many loose objects, but not too many
173 * packs, we run "repack -d -l". If there are too many packs,
174 * we run "repack -A -d -l". Otherwise we tell the caller
175 * there is no need.
176 */
177 if (too_many_packs())
178 add_repack_all_option();
179 else if (!too_many_loose_objects())
180 return 0;
181
182 if (run_hook_le(NULL, "pre-auto-gc", NULL))
183 return 0;
184 return 1;
185 }
186
187 /* return NULL on success, else hostname running the gc */
188 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
189 {
190 static struct lock_file lock;
191 char my_host[128];
192 struct strbuf sb = STRBUF_INIT;
193 struct stat st;
194 uintmax_t pid;
195 FILE *fp;
196 int fd;
197
198 if (pidfile)
199 /* already locked */
200 return NULL;
201
202 if (gethostname(my_host, sizeof(my_host)))
203 strcpy(my_host, "unknown");
204
205 fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
206 LOCK_DIE_ON_ERROR);
207 if (!force) {
208 static char locking_host[128];
209 int should_exit;
210 fp = fopen(git_path("gc.pid"), "r");
211 memset(locking_host, 0, sizeof(locking_host));
212 should_exit =
213 fp != NULL &&
214 !fstat(fileno(fp), &st) &&
215 /*
216 * 12 hour limit is very generous as gc should
217 * never take that long. On the other hand we
218 * don't really need a strict limit here,
219 * running gc --auto one day late is not a big
220 * problem. --force can be used in manual gc
221 * after the user verifies that no gc is
222 * running.
223 */
224 time(NULL) - st.st_mtime <= 12 * 3600 &&
225 fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
226 /* be gentle to concurrent "gc" on remote hosts */
227 (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
228 if (fp != NULL)
229 fclose(fp);
230 if (should_exit) {
231 if (fd >= 0)
232 rollback_lock_file(&lock);
233 *ret_pid = pid;
234 return locking_host;
235 }
236 }
237
238 strbuf_addf(&sb, "%"PRIuMAX" %s",
239 (uintmax_t) getpid(), my_host);
240 write_in_full(fd, sb.buf, sb.len);
241 strbuf_release(&sb);
242 commit_lock_file(&lock);
243
244 pidfile = git_pathdup("gc.pid");
245 sigchain_push_common(remove_pidfile_on_signal);
246 atexit(remove_pidfile);
247
248 return NULL;
249 }
250
251 static int gc_before_repack(void)
252 {
253 if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
254 return error(FAILED_RUN, pack_refs_cmd.argv[0]);
255
256 if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
257 return error(FAILED_RUN, reflog.argv[0]);
258
259 pack_refs = 0;
260 prune_reflogs = 0;
261 return 0;
262 }
263
264 int cmd_gc(int argc, const char **argv, const char *prefix)
265 {
266 int aggressive = 0;
267 int auto_gc = 0;
268 int quiet = 0;
269 int force = 0;
270 const char *name;
271 pid_t pid;
272
273 struct option builtin_gc_options[] = {
274 OPT__QUIET(&quiet, N_("suppress progress reporting")),
275 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
276 N_("prune unreferenced objects"),
277 PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
278 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
279 OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
280 OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
281 OPT_END()
282 };
283
284 if (argc == 2 && !strcmp(argv[1], "-h"))
285 usage_with_options(builtin_gc_usage, builtin_gc_options);
286
287 argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
288 argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
289 argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
290 argv_array_pushl(&prune, "prune", "--expire", NULL );
291 argv_array_pushl(&rerere, "rerere", "gc", NULL);
292
293 gc_config();
294
295 if (pack_refs < 0)
296 pack_refs = !is_bare_repository();
297
298 argc = parse_options(argc, argv, prefix, builtin_gc_options,
299 builtin_gc_usage, 0);
300 if (argc > 0)
301 usage_with_options(builtin_gc_usage, builtin_gc_options);
302
303 if (aggressive) {
304 argv_array_push(&repack, "-f");
305 if (aggressive_depth > 0)
306 argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
307 if (aggressive_window > 0)
308 argv_array_pushf(&repack, "--window=%d", aggressive_window);
309 }
310 if (quiet)
311 argv_array_push(&repack, "-q");
312
313 if (auto_gc) {
314 /*
315 * Auto-gc should be least intrusive as possible.
316 */
317 if (!need_to_gc())
318 return 0;
319 if (!quiet) {
320 if (detach_auto)
321 fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
322 else
323 fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
324 fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
325 }
326 if (detach_auto) {
327 if (gc_before_repack())
328 return -1;
329 /*
330 * failure to daemonize is ok, we'll continue
331 * in foreground
332 */
333 daemonize();
334 }
335 } else
336 add_repack_all_option();
337
338 name = lock_repo_for_gc(force, &pid);
339 if (name) {
340 if (auto_gc)
341 return 0; /* be quiet on --auto */
342 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
343 name, (uintmax_t)pid);
344 }
345
346 if (gc_before_repack())
347 return -1;
348
349 if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
350 return error(FAILED_RUN, repack.argv[0]);
351
352 if (prune_expire) {
353 argv_array_push(&prune, prune_expire);
354 if (quiet)
355 argv_array_push(&prune, "--no-progress");
356 if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
357 return error(FAILED_RUN, prune.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 }