Simplify computation of next snapshot time.
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6 #include <string.h>
7 #include <stdlib.h>
8 #include <stdarg.h>
9 #include <assert.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <signal.h>
13 #include <ctype.h>
14 #include <sys/stat.h>
15 #include <unistd.h>
16 #include <inttypes.h>
17 #include <sys/time.h>
18 #include <time.h>
19 #include <sys/wait.h>
20 #include <fnmatch.h>
21 #include <limits.h>
22
23
24 #include "gcc-compat.h"
25 #include "cmdline.h"
26 #include "log.h"
27 #include "string.h"
28 #include "error.h"
29 #include "fd.h"
30 #include "exec.h"
31 #include "daemon.h"
32 #include "signal.h"
33 #include "df.h"
34 #include "time.h"
35 #include "snap.h"
36
37 /** Command line and config file options. */
38 static struct gengetopt_args_info conf;
39 /** Non-NULL if we log to a file. */
40 static FILE *logfile;
41 /** The read end of the signal pipe */
42 static int signal_pipe;
43 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
44 static pid_t create_pid;
45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
46 static int create_process_stopped;
47 /** Process id of current pre-remove/rm/post-remove process. */
48 static pid_t remove_pid;
49 /** When the next snapshot is due. */
50 static int64_t next_snapshot_time;
51 /** When to try to remove something. */
52 static struct timeval next_removal_check;
53 /** Creation time of the snapshot currently being created. */
54 static int64_t current_snapshot_creation_time;
55 /** The snapshot currently being removed. */
56 struct snapshot *snapshot_currently_being_removed;
57 /** Needed by the post-create hook. */
58 static char *path_to_last_complete_snapshot;
59 static char *name_of_reference_snapshot;
60 /** \sa \ref snap.h for details. */
61 enum hook_status snapshot_creation_status;
62 /** \sa \ref snap.h for details. */
63 enum hook_status snapshot_removal_status;
64
65
66 DEFINE_DSS_ERRLIST;
67
68
69 /* a litte cpp magic helps to DRY */
70 #define COMMANDS \
71 COMMAND(ls) \
72 COMMAND(create) \
73 COMMAND(prune) \
74 COMMAND(run)
75 #define COMMAND(x) static int com_ ##x(void);
76 COMMANDS
77 #undef COMMAND
78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
79 static int call_command_handler(void)
80 {
81 COMMANDS
82 DSS_EMERG_LOG("BUG: did not find command handler\n");
83 return -E_BUG;
84 }
85 #undef COMMAND
86 #undef COMMANDS
87
88 /**
89 * The log function of dss.
90 *
91 * \param ll Loglevel.
92 * \param fml Usual format string.
93 *
94 * All DSS_XXX_LOG() macros use this function.
95 */
96 __printf_2_3 void dss_log(int ll, const char* fmt,...)
97 {
98 va_list argp;
99 FILE *outfd;
100 struct tm *tm;
101 time_t t1;
102 char str[255] = "";
103
104 if (ll < conf.loglevel_arg)
105 return;
106 outfd = logfile? logfile : stderr;
107 time(&t1);
108 tm = localtime(&t1);
109 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
110 fprintf(outfd, "%s ", str);
111 if (conf.loglevel_arg <= INFO)
112 fprintf(outfd, "%i: ", ll);
113 va_start(argp, fmt);
114 vfprintf(outfd, fmt, argp);
115 va_end(argp);
116 }
117
118 /**
119 * Print a message either to stdout or to the log file.
120 */
121 static __printf_1_2 void dss_msg(const char* fmt,...)
122 {
123 FILE *outfd = conf.daemon_given? logfile : stdout;
124 va_list argp;
125 va_start(argp, fmt);
126 vfprintf(outfd, fmt, argp);
127 va_end(argp);
128 }
129
130 static int disk_space_low(void)
131 {
132 struct disk_space ds;
133 int ret = get_disk_space(".", &ds);
134
135 if (ret < 0)
136 return ret;
137 if (conf.min_free_mb_arg)
138 if (ds.free_mb < conf.min_free_mb_arg)
139 return 1;
140 if (conf.min_free_percent_arg)
141 if (ds.percent_free < conf.min_free_percent_arg)
142 return 1;
143 if (conf.min_free_percent_inodes_arg)
144 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
145 return 1;
146 return 0;
147 }
148
149 static void dss_get_snapshot_list(struct snapshot_list *sl)
150 {
151 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
152 }
153
154 static int next_snapshot_is_due(void)
155 {
156 int64_t x = 0, now = get_current_time(), unit_interval
157 = 24 * 3600 * conf.unit_interval_arg;
158 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
159 num_complete_snapshots = 0;
160 int i, ret;
161 struct snapshot *s = NULL;
162 struct snapshot_list sl;
163
164 if (next_snapshot_time > now)
165 return 0;
166 assert(snapshot_creation_status == HS_READY);
167 current_snapshot_creation_time = 0;
168 dss_get_snapshot_list(&sl);
169 FOR_EACH_SNAPSHOT(s, i, &sl) {
170 if (!(s->flags & SS_COMPLETE))
171 continue;
172 num_complete_snapshots++;
173 x += s->completion_time - s->creation_time;
174 }
175 assert(x >= 0);
176
177 next_snapshot_time = now;
178 if (num_complete_snapshots == 0)
179 goto out;
180 x /= num_complete_snapshots; /* avg time to create one snapshot */
181 if (unit_interval < x * wanted) /* oops, no sleep at all */
182 goto out;
183 next_snapshot_time = s->completion_time + unit_interval / wanted - x;
184 out:
185 free_snapshot_list(&sl);
186 ret = next_snapshot_time <= now;
187 if (ret == 0)
188 DSS_DEBUG_LOG("next snapshot due in %lu seconds\n",
189 next_snapshot_time - now);
190 else
191 DSS_DEBUG_LOG("next snapshot: now\n");
192 return ret;
193 }
194
195 static int pre_create_hook(void)
196 {
197 int ret, fds[3] = {0, 0, 0};
198
199 assert(snapshot_creation_status == HS_READY);
200 if (!conf.pre_create_hook_given) {
201 snapshot_creation_status = HS_PRE_SUCCESS;
202 return 0;
203 }
204 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
205 ret = dss_exec_cmdline_pid(&create_pid,
206 conf.pre_create_hook_arg, fds);
207 if (ret < 0)
208 return ret;
209 snapshot_creation_status = HS_PRE_RUNNING;
210 return ret;
211 }
212
213 static int pre_remove_hook(struct snapshot *s, const char *why)
214 {
215 int ret, fds[3] = {0, 0, 0};
216 char *cmd;
217
218 if (!s)
219 return 0;
220 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
221 assert(snapshot_removal_status == HS_READY);
222 assert(remove_pid == 0);
223 assert(!snapshot_currently_being_removed);
224
225 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
226 *snapshot_currently_being_removed = *s;
227 snapshot_currently_being_removed->name = dss_strdup(s->name);
228
229 if (!conf.pre_remove_hook_given) {
230 snapshot_removal_status = HS_PRE_SUCCESS;
231 return 0;
232 }
233 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
234 conf.dest_dir_arg, s->name);
235 DSS_DEBUG_LOG("executing %s\n", cmd);
236 ret = dss_exec_cmdline_pid(&remove_pid,
237 conf.pre_remove_hook_arg, fds);
238 free(cmd);
239 if (ret < 0)
240 return ret;
241 snapshot_removal_status = HS_PRE_RUNNING;
242 return ret;
243 }
244
245 static int exec_rm(void)
246 {
247 struct snapshot *s = snapshot_currently_being_removed;
248 int fds[3] = {0, 0, 0};
249 char *new_name = being_deleted_name(s);
250 char *argv[] = {"rm", "-rf", new_name, NULL};
251 int ret;
252
253 assert(snapshot_removal_status == HS_PRE_SUCCESS);
254 assert(remove_pid == 0);
255
256 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
257 ret = dss_rename(s->name, new_name);
258 if (ret < 0)
259 goto out;
260 ret = dss_exec(&remove_pid, argv[0], argv, fds);
261 if (ret < 0)
262 goto out;
263 snapshot_removal_status = HS_RUNNING;
264 out:
265 free(new_name);
266 return ret;
267 }
268
269 static int snapshot_is_being_created(struct snapshot *s)
270 {
271 return s->creation_time == current_snapshot_creation_time;
272 }
273
274 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
275 {
276 struct snapshot *s;
277 int i;
278
279 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
280 FOR_EACH_SNAPSHOT(s, i, sl) {
281 if (snapshot_is_being_created(s))
282 continue;
283 /*
284 * We know that no rm is currently running, so if s is marked
285 * as being deleted, a previously started rm must have failed.
286 */
287 if (s->flags & SS_BEING_DELETED)
288 return s;
289
290 if (s->flags & SS_COMPLETE) /* good snapshot */
291 continue;
292 /*
293 * This snapshot is incomplete and it is not the snapshot
294 * currently being created. However, we must not remove it if
295 * rsync is about to be restarted. As only the newest snapshot
296 * can be restarted, this snapshot is orphaned if it is not the
297 * newest snapshot or if we are not about to restart rsync.
298 */
299 if (get_newest_snapshot(sl) != s)
300 return s;
301 if (snapshot_creation_status != HS_NEEDS_RESTART)
302 return s;
303 }
304 /* no orphaned snapshots */
305 return NULL;
306 }
307
308 static int is_reference_snapshot(struct snapshot *s)
309 {
310 if (!name_of_reference_snapshot)
311 return 0;
312 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
313 }
314
315 /*
316 * return: 0: no redundant snapshots, 1: rm process started, negative: error
317 */
318 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
319 {
320 int i, interval;
321 struct snapshot *s;
322 unsigned missing = 0;
323
324 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
325 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
326 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
327 unsigned num = sl->interval_count[interval];
328 struct snapshot *victim = NULL, *prev = NULL;
329 int64_t score = LONG_MAX;
330
331 if (keep >= num)
332 missing += keep - num;
333 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
334 // interval, keep, num, missing);
335 if (keep + missing >= num)
336 continue;
337 /* redundant snapshot in this interval, pick snapshot with lowest score */
338 FOR_EACH_SNAPSHOT(s, i, sl) {
339 int64_t this_score;
340
341 if (snapshot_is_being_created(s))
342 continue;
343 if (is_reference_snapshot(s))
344 continue;
345 //DSS_DEBUG_LOG("checking %s\n", s->name);
346 if (s->interval > interval) {
347 prev = s;
348 continue;
349 }
350 if (s->interval < interval)
351 break;
352 if (!victim) {
353 victim = s;
354 prev = s;
355 continue;
356 }
357 assert(prev);
358 /* check if s is a better victim */
359 this_score = s->creation_time - prev->creation_time;
360 assert(this_score >= 0);
361 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
362 if (this_score < score) {
363 score = this_score;
364 victim = s;
365 }
366 prev = s;
367 }
368 assert(victim);
369 return victim;
370 }
371 return NULL;
372 }
373
374 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
375 {
376 int i;
377 struct snapshot *s;
378
379 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
380 conf.num_intervals_arg);
381 FOR_EACH_SNAPSHOT(s, i, sl) {
382 if (snapshot_is_being_created(s))
383 continue;
384 if (is_reference_snapshot(s))
385 continue;
386 if (s->interval < conf.num_intervals_arg)
387 continue;
388 return s;
389 }
390 return NULL;
391 }
392
393 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
394 {
395 int i;
396 struct snapshot *s;
397 FOR_EACH_SNAPSHOT(s, i, sl) {
398 if (snapshot_is_being_created(s))
399 continue;
400 if (is_reference_snapshot(s))
401 continue;
402 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
403 return s;
404 }
405 return NULL;
406 }
407
408 static int rename_incomplete_snapshot(int64_t start)
409 {
410 char *old_name;
411 int ret;
412
413 free(path_to_last_complete_snapshot);
414 ret = complete_name(start, get_current_time(),
415 &path_to_last_complete_snapshot);
416 if (ret < 0)
417 return ret;
418 old_name = incomplete_name(start);
419 ret = dss_rename(old_name, path_to_last_complete_snapshot);
420 if (ret >= 0)
421 DSS_NOTICE_LOG("%s -> %s\n", old_name,
422 path_to_last_complete_snapshot);
423 free(old_name);
424 return ret;
425 }
426
427 static int try_to_free_disk_space(void)
428 {
429 int ret;
430 struct snapshot_list sl;
431 struct snapshot *victim;
432 struct timeval now;
433 const char *why;
434 int low_disk_space;
435
436 ret = disk_space_low();
437 if (ret < 0)
438 return ret;
439 low_disk_space = ret;
440 gettimeofday(&now, NULL);
441 if (tv_diff(&next_removal_check, &now, NULL) > 0)
442 return 0;
443 if (!low_disk_space) {
444 if (conf.keep_redundant_given)
445 return 0;
446 if (snapshot_creation_status != HS_READY)
447 return 0;
448 if (next_snapshot_is_due())
449 return 0;
450 }
451 dss_get_snapshot_list(&sl);
452 ret = 0;
453 if (!low_disk_space && sl.num_snapshots <= 1)
454 goto out;
455 why = "outdated";
456 victim = find_outdated_snapshot(&sl);
457 if (victim)
458 goto remove;
459 why = "redundant";
460 victim = find_redundant_snapshot(&sl);
461 if (victim)
462 goto remove;
463 /* try harder only if disk space is low */
464 if (!low_disk_space)
465 goto out;
466 why = "orphaned";
467 victim = find_orphaned_snapshot(&sl);
468 if (victim)
469 goto remove;
470 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
471 victim = find_oldest_removable_snapshot(&sl);
472 if (victim)
473 goto remove;
474 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
475 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
476 goto out;
477 remove:
478 ret = pre_remove_hook(victim, why);
479 out:
480 free_snapshot_list(&sl);
481 return ret;
482 }
483
484 static int post_create_hook(void)
485 {
486 int ret, fds[3] = {0, 0, 0};
487 char *cmd;
488
489 if (!conf.post_create_hook_given) {
490 snapshot_creation_status = HS_READY;
491 return 0;
492 }
493 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
494 conf.dest_dir_arg, path_to_last_complete_snapshot);
495 DSS_NOTICE_LOG("executing %s\n", cmd);
496 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
497 free(cmd);
498 if (ret < 0)
499 return ret;
500 snapshot_creation_status = HS_POST_RUNNING;
501 return ret;
502 }
503
504 static int post_remove_hook(void)
505 {
506 int ret, fds[3] = {0, 0, 0};
507 char *cmd;
508 struct snapshot *s = snapshot_currently_being_removed;
509
510 assert(s);
511
512 if (!conf.post_remove_hook_given) {
513 snapshot_removal_status = HS_READY;
514 return 0;
515 }
516 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
517 conf.dest_dir_arg, s->name);
518 DSS_NOTICE_LOG("executing %s\n", cmd);
519 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
520 free(cmd);
521 if (ret < 0)
522 return ret;
523 snapshot_removal_status = HS_POST_RUNNING;
524 return ret;
525 }
526
527 static void kill_process(pid_t pid)
528 {
529 if (!pid)
530 return;
531 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
532 kill(pid, SIGTERM);
533 }
534
535 static void stop_create_process(void)
536 {
537 if (!create_pid || create_process_stopped)
538 return;
539 kill(SIGSTOP, create_pid);
540 create_process_stopped = 1;
541 }
542
543 static void restart_create_process(void)
544 {
545 if (!create_pid || !create_process_stopped)
546 return;
547 kill (SIGCONT, create_pid);
548 create_process_stopped = 0;
549 }
550
551 /**
552 * Print a log message about the exit status of a child.
553 */
554 static void log_termination_msg(pid_t pid, int status)
555 {
556 if (WIFEXITED(status))
557 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
558 WEXITSTATUS(status));
559 else if (WIFSIGNALED(status))
560 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
561 WTERMSIG(status));
562 else
563 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
564 }
565
566 static int wait_for_process(pid_t pid, int *status)
567 {
568 int ret;
569
570 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
571 for (;;) {
572 fd_set rfds;
573
574 FD_ZERO(&rfds);
575 FD_SET(signal_pipe, &rfds);
576 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
577 if (ret < 0)
578 break;
579 ret = next_signal();
580 if (!ret)
581 continue;
582 if (ret == SIGCHLD) {
583 ret = waitpid(pid, status, 0);
584 if (ret >= 0)
585 break;
586 if (errno != EINTR) { /* error */
587 ret = -ERRNO_TO_DSS_ERROR(errno);
588 break;
589 }
590 }
591 /* SIGINT or SIGTERM */
592 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
593 kill(pid, SIGTERM);
594 }
595 if (ret < 0)
596 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
597 else
598 log_termination_msg(pid, *status);
599 return ret;
600 }
601
602 static void handle_pre_remove_exit(int status)
603 {
604 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
605 snapshot_removal_status = HS_READY;
606 gettimeofday(&next_removal_check, NULL);
607 next_removal_check.tv_sec += 60;
608 return;
609 }
610 snapshot_removal_status = HS_PRE_SUCCESS;
611 }
612
613 static int handle_rm_exit(int status)
614 {
615 if (!WIFEXITED(status)) {
616 snapshot_removal_status = HS_READY;
617 return -E_INVOLUNTARY_EXIT;
618 }
619 if (WEXITSTATUS(status)) {
620 snapshot_removal_status = HS_READY;
621 return -E_BAD_EXIT_CODE;
622 }
623 if (conf.post_remove_hook_given)
624 snapshot_removal_status = HS_SUCCESS;
625 else
626 snapshot_removal_status = HS_READY;
627 return 1;
628 }
629
630 static void handle_post_remove_exit(void)
631 {
632 snapshot_removal_status = HS_READY;
633 }
634
635 static int handle_remove_exit(int status)
636 {
637 int ret;
638 struct snapshot *s = snapshot_currently_being_removed;
639
640 assert(s);
641 switch (snapshot_removal_status) {
642 case HS_PRE_RUNNING:
643 handle_pre_remove_exit(status);
644 ret = 1;
645 break;
646 case HS_RUNNING:
647 ret = handle_rm_exit(status);
648 break;
649 case HS_POST_RUNNING:
650 handle_post_remove_exit();
651 ret = 1;
652 break;
653 default:
654 ret = -E_BUG;
655 }
656 if (snapshot_removal_status == HS_READY) {
657 free(s->name);
658 free(s);
659 snapshot_currently_being_removed = NULL;
660 }
661 remove_pid = 0;
662 return ret;
663 }
664
665 static int wait_for_remove_process(void)
666 {
667 int status, ret;
668
669 assert(remove_pid);
670 assert(
671 snapshot_removal_status == HS_PRE_RUNNING ||
672 snapshot_removal_status == HS_RUNNING ||
673 snapshot_removal_status == HS_POST_RUNNING
674 );
675 ret = wait_for_process(remove_pid, &status);
676 if (ret < 0)
677 return ret;
678 return handle_remove_exit(status);
679 }
680
681 static int handle_rsync_exit(int status)
682 {
683 int es, ret;
684
685 if (!WIFEXITED(status)) {
686 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
687 ret = -E_INVOLUNTARY_EXIT;
688 snapshot_creation_status = HS_READY;
689 goto out;
690 }
691 es = WEXITSTATUS(status);
692 /*
693 * Restart rsync on non-fatal errors:
694 * 12: Error in rsync protocol data stream
695 * 13: Errors with program diagnostics
696 */
697 if (es == 12 || es == 13) {
698 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
699 (int)create_pid, es);
700 snapshot_creation_status = HS_NEEDS_RESTART;
701 next_snapshot_time = get_current_time() + 60;
702 ret = 1;
703 goto out;
704 }
705 if (es != 0 && es != 23 && es != 24) {
706 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
707 ret = -E_BAD_EXIT_CODE;
708 snapshot_creation_status = HS_READY;
709 goto out;
710 }
711 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
712 if (ret < 0)
713 goto out;
714 snapshot_creation_status = HS_SUCCESS;
715 free(name_of_reference_snapshot);
716 name_of_reference_snapshot = NULL;
717 out:
718 create_pid = 0;
719 create_process_stopped = 0;
720 return ret;
721 }
722
723 static int handle_pre_create_hook_exit(int status)
724 {
725 int es, ret;
726 static int warn_count;
727
728 if (!WIFEXITED(status)) {
729 snapshot_creation_status = HS_READY;
730 ret = -E_INVOLUNTARY_EXIT;
731 goto out;
732 }
733 es = WEXITSTATUS(status);
734 if (es) {
735 if (!warn_count--) {
736 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
737 conf.pre_create_hook_arg, es);
738 DSS_NOTICE_LOG("deferring snapshot creation...\n");
739 warn_count = 60; /* warn only once per hour */
740 }
741 next_snapshot_time = get_current_time() + 60;
742 snapshot_creation_status = HS_READY;
743 ret = 0;
744 goto out;
745 }
746 warn_count = 0;
747 snapshot_creation_status = HS_PRE_SUCCESS;
748 ret = 1;
749 out:
750 create_pid = 0;
751 return ret;
752 }
753
754 static int handle_sigchld(void)
755 {
756 pid_t pid;
757 int status, ret = reap_child(&pid, &status);
758
759 if (ret <= 0)
760 return ret;
761
762 if (pid == create_pid) {
763 switch (snapshot_creation_status) {
764 case HS_PRE_RUNNING:
765 return handle_pre_create_hook_exit(status);
766 case HS_RUNNING:
767 return handle_rsync_exit(status);
768 case HS_POST_RUNNING:
769 snapshot_creation_status = HS_READY;
770 return 1;
771 default:
772 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
773 snapshot_creation_status);
774 return -E_BUG;
775 }
776 }
777 if (pid == remove_pid) {
778 ret = handle_remove_exit(status);
779 if (ret < 0)
780 return ret;
781 return ret;
782 }
783 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
784 return -E_BUG;
785 }
786
787 static int check_config(void)
788 {
789 if (conf.unit_interval_arg <= 0) {
790 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
791 return -E_INVALID_NUMBER;
792 }
793 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
794 if (conf.num_intervals_arg <= 0) {
795 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
796 return -E_INVALID_NUMBER;
797 }
798 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
799 return 1;
800 }
801
802 static int parse_config_file(int override)
803 {
804 int ret;
805 char *config_file;
806 struct stat statbuf;
807 char *old_logfile_arg = NULL;
808 int old_daemon_given = 0;
809
810 if (conf.config_file_given)
811 config_file = dss_strdup(conf.config_file_arg);
812 else {
813 char *home = get_homedir();
814 config_file = make_message("%s/.dssrc", home);
815 free(home);
816 }
817 if (override) { /* SIGHUP */
818 if (conf.logfile_given)
819 old_logfile_arg = dss_strdup(conf.logfile_arg);
820 old_daemon_given = conf.daemon_given;
821 }
822
823 ret = stat(config_file, &statbuf);
824 if (ret && conf.config_file_given) {
825 ret = -ERRNO_TO_DSS_ERROR(errno);
826 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
827 goto out;
828 }
829 if (!ret) {
830 struct cmdline_parser_params params = {
831 .override = override,
832 .initialize = 0,
833 .check_required = 1,
834 .check_ambiguity = 0,
835 .print_errors = 1
836 };
837 if (override) { /* invalidate all rsync options */
838 int i;
839
840 for (i = 0; i < conf.rsync_option_given; i++) {
841 free(conf.rsync_option_arg[i]);
842 conf.rsync_option_arg[i] = NULL;
843 }
844 conf.rsync_option_given = 0;
845 }
846 cmdline_parser_config_file(config_file, &conf, &params);
847 }
848 ret = check_config();
849 if (ret < 0)
850 goto out;
851 if (override) {
852 /* don't change daemon mode on SIGHUP */
853 conf.daemon_given = old_daemon_given;
854 close_log(logfile);
855 logfile = NULL;
856 if (conf.logfile_given)
857 free(old_logfile_arg);
858 else if (conf.daemon_given) { /* re-use old logfile */
859 conf.logfile_arg = old_logfile_arg;
860 conf.logfile_given = 1;
861 }
862 }
863 if (conf.logfile_given) {
864 logfile = open_log(conf.logfile_arg);
865 log_welcome(conf.loglevel_arg);
866 }
867 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
868 // cmdline_parser_dump(logfile? logfile : stdout, &conf);
869 out:
870 free(config_file);
871 if (ret < 0)
872 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
873 return ret;
874 }
875
876 static int change_to_dest_dir(void)
877 {
878 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
879 return dss_chdir(conf.dest_dir_arg);
880 }
881
882 static int handle_sighup(void)
883 {
884 int ret;
885
886 DSS_NOTICE_LOG("SIGHUP\n");
887 ret = parse_config_file(1);
888 if (ret < 0)
889 return ret;
890 return change_to_dest_dir();
891 }
892
893 static int handle_signal(void)
894 {
895 int sig, ret = next_signal();
896
897 if (ret <= 0)
898 goto out;
899 sig = ret;
900 switch (sig) {
901 case SIGINT:
902 case SIGTERM:
903 restart_create_process();
904 kill_process(create_pid);
905 kill_process(remove_pid);
906 ret = -E_SIGNAL;
907 break;
908 case SIGHUP:
909 ret = handle_sighup();
910 break;
911 case SIGCHLD:
912 ret = handle_sigchld();
913 break;
914 }
915 out:
916 if (ret < 0)
917 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
918 return ret;
919 }
920
921 /*
922 * We can not use rsync locally if the local user is different from the remote
923 * user or if the src dir is not on the local host (or both).
924 */
925 static int use_rsync_locally(char *logname)
926 {
927 char *h = conf.remote_host_arg;
928
929 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
930 return 0;
931 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
932 return 0;
933 return 1;
934 }
935
936 static void create_rsync_argv(char ***argv, int64_t *num)
937 {
938 char *logname;
939 int i = 0, j;
940 struct snapshot_list sl;
941
942 dss_get_snapshot_list(&sl);
943 assert(!name_of_reference_snapshot);
944 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
945 free_snapshot_list(&sl);
946
947 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
948 (*argv)[i++] = dss_strdup("rsync");
949 (*argv)[i++] = dss_strdup("-aq");
950 (*argv)[i++] = dss_strdup("--delete");
951 for (j = 0; j < conf.rsync_option_given; j++)
952 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
953 if (name_of_reference_snapshot) {
954 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
955 (*argv)[i++] = make_message("--link-dest=../%s",
956 name_of_reference_snapshot);
957 } else
958 DSS_INFO_LOG("no suitable reference snapshot found\n");
959 logname = dss_logname();
960 if (use_rsync_locally(logname))
961 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
962 else
963 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
964 conf.remote_user_arg : logname,
965 conf.remote_host_arg, conf.source_dir_arg);
966 free(logname);
967 *num = get_current_time();
968 (*argv)[i++] = incomplete_name(*num);
969 (*argv)[i++] = NULL;
970 for (j = 0; j < i; j++)
971 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
972 }
973
974 static void free_rsync_argv(char **argv)
975 {
976 int i;
977
978 if (!argv)
979 return;
980 for (i = 0; argv[i]; i++)
981 free(argv[i]);
982 free(argv);
983 }
984
985 static int create_snapshot(char **argv)
986 {
987 int ret, fds[3] = {0, 0, 0};
988 char *name;
989
990 name = incomplete_name(current_snapshot_creation_time);
991 DSS_NOTICE_LOG("creating new snapshot %s\n", name);
992 free(name);
993 ret = dss_exec(&create_pid, argv[0], argv, fds);
994 if (ret < 0)
995 return ret;
996 snapshot_creation_status = HS_RUNNING;
997 return ret;
998 }
999
1000 static int select_loop(void)
1001 {
1002 int ret;
1003 /* check every 60 seconds for free disk space */
1004 struct timeval tv;
1005 char **rsync_argv = NULL;
1006
1007 for (;;) {
1008 fd_set rfds;
1009 struct timeval *tvp;
1010
1011 if (remove_pid)
1012 tvp = NULL; /* sleep until rm hook/process dies */
1013 else { /* sleep one minute */
1014 tv.tv_sec = 60;
1015 tv.tv_usec = 0;
1016 tvp = &tv;
1017 }
1018 FD_ZERO(&rfds);
1019 FD_SET(signal_pipe, &rfds);
1020 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1021 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1022 if (ret < 0)
1023 goto out;
1024 if (FD_ISSET(signal_pipe, &rfds)) {
1025 ret = handle_signal();
1026 if (ret < 0)
1027 goto out;
1028 }
1029 if (remove_pid)
1030 continue;
1031 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1032 ret = exec_rm();
1033 if (ret < 0)
1034 goto out;
1035 continue;
1036 }
1037 if (snapshot_removal_status == HS_SUCCESS) {
1038 ret = post_remove_hook();
1039 if (ret < 0)
1040 goto out;
1041 continue;
1042 }
1043 ret = try_to_free_disk_space();
1044 if (ret < 0)
1045 goto out;
1046 if (snapshot_removal_status != HS_READY) {
1047 stop_create_process();
1048 continue;
1049 }
1050 restart_create_process();
1051 switch (snapshot_creation_status) {
1052 case HS_READY:
1053 if (!next_snapshot_is_due())
1054 continue;
1055 ret = pre_create_hook();
1056 if (ret < 0)
1057 goto out;
1058 continue;
1059 case HS_PRE_RUNNING:
1060 case HS_RUNNING:
1061 case HS_POST_RUNNING:
1062 continue;
1063 case HS_PRE_SUCCESS:
1064 free_rsync_argv(rsync_argv);
1065 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1066 /* fall through */
1067 case HS_NEEDS_RESTART:
1068 ret = create_snapshot(rsync_argv);
1069 if (ret < 0)
1070 goto out;
1071 continue;
1072 case HS_SUCCESS:
1073 ret = post_create_hook();
1074 if (ret < 0)
1075 goto out;
1076 continue;
1077 }
1078 }
1079 out:
1080 return ret;
1081 }
1082
1083 static void exit_hook(int exit_code)
1084 {
1085 int fds[3] = {0, 0, 0};
1086 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1087 pid_t pid;
1088
1089 if (!conf.exit_hook_given)
1090 return;
1091 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1092 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1093 }
1094
1095 static int com_run(void)
1096 {
1097 int ret;
1098
1099 if (conf.dry_run_given) {
1100 DSS_ERROR_LOG("dry_run not supported by this command\n");
1101 return -E_SYNTAX;
1102 }
1103 ret = install_sighandler(SIGHUP);
1104 if (ret < 0)
1105 return ret;
1106 ret = select_loop();
1107 if (ret >= 0) /* impossible */
1108 ret = -E_BUG;
1109 exit_hook(ret);
1110 return ret;
1111 }
1112
1113 static int com_prune(void)
1114 {
1115 int ret;
1116 struct snapshot_list sl;
1117 struct snapshot *victim;
1118 struct disk_space ds;
1119 const char *why;
1120
1121 ret = get_disk_space(".", &ds);
1122 if (ret < 0)
1123 return ret;
1124 log_disk_space(&ds);
1125 dss_get_snapshot_list(&sl);
1126 why = "outdated";
1127 victim = find_outdated_snapshot(&sl);
1128 if (victim)
1129 goto rm;
1130 why = "redundant";
1131 victim = find_redundant_snapshot(&sl);
1132 if (victim)
1133 goto rm;
1134 ret = 0;
1135 goto out;
1136 rm:
1137 if (conf.dry_run_given) {
1138 dss_msg("%s snapshot %s (interval = %i)\n",
1139 why, victim->name, victim->interval);
1140 ret = 0;
1141 goto out;
1142 }
1143 ret = pre_remove_hook(victim, why);
1144 if (ret < 0)
1145 goto out;
1146 if (snapshot_removal_status == HS_PRE_RUNNING) {
1147 ret = wait_for_remove_process();
1148 if (ret < 0)
1149 goto out;
1150 if (snapshot_removal_status != HS_PRE_SUCCESS)
1151 goto out;
1152 }
1153 ret = exec_rm();
1154 if (ret < 0)
1155 goto out;
1156 ret = wait_for_remove_process();
1157 if (ret < 0)
1158 goto out;
1159 if (snapshot_removal_status != HS_SUCCESS)
1160 goto out;
1161 ret = post_remove_hook();
1162 if (ret < 0)
1163 goto out;
1164 if (snapshot_removal_status != HS_POST_RUNNING)
1165 goto out;
1166 ret = wait_for_remove_process();
1167 if (ret < 0)
1168 goto out;
1169 ret = 1;
1170 out:
1171 free_snapshot_list(&sl);
1172 return ret;
1173 }
1174
1175 static int com_create(void)
1176 {
1177 int ret, status;
1178 char **rsync_argv;
1179
1180 if (conf.dry_run_given) {
1181 int i;
1182 char *msg = NULL;
1183 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1184 for (i = 0; rsync_argv[i]; i++) {
1185 char *tmp = msg;
1186 msg = make_message("%s%s%s", tmp? tmp : "",
1187 tmp? " " : "", rsync_argv[i]);
1188 free(tmp);
1189 }
1190 free_rsync_argv(rsync_argv);
1191 dss_msg("%s\n", msg);
1192 free(msg);
1193 return 1;
1194 }
1195 ret = pre_create_hook();
1196 if (ret < 0)
1197 return ret;
1198 if (create_pid) {
1199 ret = wait_for_process(create_pid, &status);
1200 if (ret < 0)
1201 return ret;
1202 ret = handle_pre_create_hook_exit(status);
1203 if (ret <= 0) /* error, or pre-create failed */
1204 return ret;
1205 }
1206 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1207 ret = create_snapshot(rsync_argv);
1208 if (ret < 0)
1209 goto out;
1210 ret = wait_for_process(create_pid, &status);
1211 if (ret < 0)
1212 goto out;
1213 ret = handle_rsync_exit(status);
1214 if (ret < 0)
1215 goto out;
1216 post_create_hook();
1217 if (create_pid)
1218 ret = wait_for_process(create_pid, &status);
1219 out:
1220 free_rsync_argv(rsync_argv);
1221 return ret;
1222 }
1223
1224 static int com_ls(void)
1225 {
1226 int i;
1227 struct snapshot_list sl;
1228 struct snapshot *s;
1229
1230 dss_get_snapshot_list(&sl);
1231 FOR_EACH_SNAPSHOT(s, i, &sl) {
1232 int64_t d = 0;
1233 if (s->flags & SS_COMPLETE)
1234 d = (s->completion_time - s->creation_time) / 60;
1235 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1236 };
1237 free_snapshot_list(&sl);
1238 return 1;
1239 }
1240
1241 static int setup_signal_handling(void)
1242 {
1243 int ret;
1244
1245 DSS_INFO_LOG("setting up signal handlers\n");
1246 signal_pipe = signal_init(); /* always successful */
1247 ret = install_sighandler(SIGINT);
1248 if (ret < 0)
1249 return ret;
1250 ret = install_sighandler(SIGTERM);
1251 if (ret < 0)
1252 return ret;
1253 return install_sighandler(SIGCHLD);
1254 }
1255
1256 /**
1257 * The main function of dss.
1258 *
1259 * \param argc Usual argument count.
1260 * \param argv Usual argument vector.
1261 */
1262 int main(int argc, char **argv)
1263 {
1264 int ret;
1265 struct cmdline_parser_params params = {
1266 .override = 0,
1267 .initialize = 1,
1268 .check_required = 0,
1269 .check_ambiguity = 0,
1270 .print_errors = 1
1271 };
1272
1273 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1274 ret = parse_config_file(0);
1275 if (ret < 0)
1276 goto out;
1277 if (conf.daemon_given)
1278 daemon_init();
1279 ret = change_to_dest_dir();
1280 if (ret < 0)
1281 goto out;
1282 ret = setup_signal_handling();
1283 if (ret < 0)
1284 goto out;
1285 ret = call_command_handler();
1286 out:
1287 if (ret < 0)
1288 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1289 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1290 }