Improve next_snapshot_is_due().
[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 int64_t compute_next_snapshot_time(void)
155 {
156 int64_t x = 0, now = get_current_time(), unit_interval
157 = 24 * 3600 * conf.unit_interval_arg, ret;
158 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
159 num_complete_snapshots = 0;
160 int i;
161 struct snapshot *s = NULL;
162 struct snapshot_list sl;
163
164 current_snapshot_creation_time = 0;
165 dss_get_snapshot_list(&sl);
166 FOR_EACH_SNAPSHOT(s, i, &sl) {
167 if (!(s->flags & SS_COMPLETE))
168 continue;
169 num_complete_snapshots++;
170 x += s->completion_time - s->creation_time;
171 }
172 assert(x >= 0);
173
174 ret = now;
175 if (num_complete_snapshots == 0)
176 goto out;
177 x /= num_complete_snapshots; /* avg time to create one snapshot */
178 if (unit_interval < x * wanted) /* oops, no sleep at all */
179 goto out;
180 ret = s->completion_time + unit_interval / wanted - x;
181 out:
182 free_snapshot_list(&sl);
183 return ret;
184 }
185
186 static inline void invalidate_next_snapshot_time(void)
187 {
188 next_snapshot_time = 0;
189 }
190
191 static inline int next_snapshot_time_is_valid(void)
192 {
193 return next_snapshot_time != 0;
194 }
195
196 static int next_snapshot_is_due(void)
197 {
198 int64_t now = get_current_time();
199
200 assert(snapshot_creation_status == HS_READY);
201 if (!next_snapshot_time_is_valid())
202 next_snapshot_time = compute_next_snapshot_time();
203 if (next_snapshot_time <= now) {
204 DSS_DEBUG_LOG("next snapshot: now\n");
205 return 1;
206 }
207 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
208 next_snapshot_time - now);
209 return 0;
210 }
211
212 static int pre_create_hook(void)
213 {
214 int ret, fds[3] = {0, 0, 0};
215
216 assert(snapshot_creation_status == HS_READY);
217 /* make sure that the next snapshot time will be recomputed */
218 invalidate_next_snapshot_time();
219 if (!conf.pre_create_hook_given) {
220 snapshot_creation_status = HS_PRE_SUCCESS;
221 return 0;
222 }
223 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
224 ret = dss_exec_cmdline_pid(&create_pid,
225 conf.pre_create_hook_arg, fds);
226 if (ret < 0)
227 return ret;
228 snapshot_creation_status = HS_PRE_RUNNING;
229 return ret;
230 }
231
232 static int pre_remove_hook(struct snapshot *s, const char *why)
233 {
234 int ret, fds[3] = {0, 0, 0};
235 char *cmd;
236
237 if (!s)
238 return 0;
239 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
240 assert(snapshot_removal_status == HS_READY);
241 assert(remove_pid == 0);
242 assert(!snapshot_currently_being_removed);
243
244 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
245 *snapshot_currently_being_removed = *s;
246 snapshot_currently_being_removed->name = dss_strdup(s->name);
247
248 if (!conf.pre_remove_hook_given) {
249 snapshot_removal_status = HS_PRE_SUCCESS;
250 return 0;
251 }
252 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
253 conf.dest_dir_arg, s->name);
254 DSS_DEBUG_LOG("executing %s\n", cmd);
255 ret = dss_exec_cmdline_pid(&remove_pid,
256 conf.pre_remove_hook_arg, fds);
257 free(cmd);
258 if (ret < 0)
259 return ret;
260 snapshot_removal_status = HS_PRE_RUNNING;
261 return ret;
262 }
263
264 static int exec_rm(void)
265 {
266 struct snapshot *s = snapshot_currently_being_removed;
267 int fds[3] = {0, 0, 0};
268 char *new_name = being_deleted_name(s);
269 char *argv[] = {"rm", "-rf", new_name, NULL};
270 int ret;
271
272 assert(snapshot_removal_status == HS_PRE_SUCCESS);
273 assert(remove_pid == 0);
274
275 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
276 ret = dss_rename(s->name, new_name);
277 if (ret < 0)
278 goto out;
279 ret = dss_exec(&remove_pid, argv[0], argv, fds);
280 if (ret < 0)
281 goto out;
282 snapshot_removal_status = HS_RUNNING;
283 out:
284 free(new_name);
285 return ret;
286 }
287
288 static int snapshot_is_being_created(struct snapshot *s)
289 {
290 return s->creation_time == current_snapshot_creation_time;
291 }
292
293 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
294 {
295 struct snapshot *s;
296 int i;
297
298 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
299 FOR_EACH_SNAPSHOT(s, i, sl) {
300 if (snapshot_is_being_created(s))
301 continue;
302 /*
303 * We know that no rm is currently running, so if s is marked
304 * as being deleted, a previously started rm must have failed.
305 */
306 if (s->flags & SS_BEING_DELETED)
307 return s;
308
309 if (s->flags & SS_COMPLETE) /* good snapshot */
310 continue;
311 /*
312 * This snapshot is incomplete and it is not the snapshot
313 * currently being created. However, we must not remove it if
314 * rsync is about to be restarted. As only the newest snapshot
315 * can be restarted, this snapshot is orphaned if it is not the
316 * newest snapshot or if we are not about to restart rsync.
317 */
318 if (get_newest_snapshot(sl) != s)
319 return s;
320 if (snapshot_creation_status != HS_NEEDS_RESTART)
321 return s;
322 }
323 /* no orphaned snapshots */
324 return NULL;
325 }
326
327 static int is_reference_snapshot(struct snapshot *s)
328 {
329 if (!name_of_reference_snapshot)
330 return 0;
331 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
332 }
333
334 /*
335 * return: 0: no redundant snapshots, 1: rm process started, negative: error
336 */
337 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
338 {
339 int i, interval;
340 struct snapshot *s;
341 unsigned missing = 0;
342
343 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
344 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
345 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
346 unsigned num = sl->interval_count[interval];
347 struct snapshot *victim = NULL, *prev = NULL;
348 int64_t score = LONG_MAX;
349
350 if (keep >= num)
351 missing += keep - num;
352 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
353 // interval, keep, num, missing);
354 if (keep + missing >= num)
355 continue;
356 /* redundant snapshot in this interval, pick snapshot with lowest score */
357 FOR_EACH_SNAPSHOT(s, i, sl) {
358 int64_t this_score;
359
360 if (snapshot_is_being_created(s))
361 continue;
362 if (is_reference_snapshot(s))
363 continue;
364 //DSS_DEBUG_LOG("checking %s\n", s->name);
365 if (s->interval > interval) {
366 prev = s;
367 continue;
368 }
369 if (s->interval < interval)
370 break;
371 if (!victim) {
372 victim = s;
373 prev = s;
374 continue;
375 }
376 assert(prev);
377 /* check if s is a better victim */
378 this_score = s->creation_time - prev->creation_time;
379 assert(this_score >= 0);
380 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
381 if (this_score < score) {
382 score = this_score;
383 victim = s;
384 }
385 prev = s;
386 }
387 assert(victim);
388 return victim;
389 }
390 return NULL;
391 }
392
393 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
394 {
395 int i;
396 struct snapshot *s;
397
398 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
399 conf.num_intervals_arg);
400 FOR_EACH_SNAPSHOT(s, i, sl) {
401 if (snapshot_is_being_created(s))
402 continue;
403 if (is_reference_snapshot(s))
404 continue;
405 if (s->interval < conf.num_intervals_arg)
406 continue;
407 return s;
408 }
409 return NULL;
410 }
411
412 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
413 {
414 int i;
415 struct snapshot *s;
416 FOR_EACH_SNAPSHOT(s, i, sl) {
417 if (snapshot_is_being_created(s))
418 continue;
419 if (is_reference_snapshot(s))
420 continue;
421 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
422 return s;
423 }
424 return NULL;
425 }
426
427 static int rename_incomplete_snapshot(int64_t start)
428 {
429 char *old_name;
430 int ret;
431
432 free(path_to_last_complete_snapshot);
433 ret = complete_name(start, get_current_time(),
434 &path_to_last_complete_snapshot);
435 if (ret < 0)
436 return ret;
437 old_name = incomplete_name(start);
438 ret = dss_rename(old_name, path_to_last_complete_snapshot);
439 if (ret >= 0)
440 DSS_NOTICE_LOG("%s -> %s\n", old_name,
441 path_to_last_complete_snapshot);
442 free(old_name);
443 return ret;
444 }
445
446 static int try_to_free_disk_space(void)
447 {
448 int ret;
449 struct snapshot_list sl;
450 struct snapshot *victim;
451 struct timeval now;
452 const char *why;
453 int low_disk_space;
454
455 ret = disk_space_low();
456 if (ret < 0)
457 return ret;
458 low_disk_space = ret;
459 gettimeofday(&now, NULL);
460 if (tv_diff(&next_removal_check, &now, NULL) > 0)
461 return 0;
462 if (!low_disk_space) {
463 if (conf.keep_redundant_given)
464 return 0;
465 if (snapshot_creation_status != HS_READY)
466 return 0;
467 if (next_snapshot_is_due())
468 return 0;
469 }
470 dss_get_snapshot_list(&sl);
471 ret = 0;
472 if (!low_disk_space && sl.num_snapshots <= 1)
473 goto out;
474 why = "outdated";
475 victim = find_outdated_snapshot(&sl);
476 if (victim)
477 goto remove;
478 why = "redundant";
479 victim = find_redundant_snapshot(&sl);
480 if (victim)
481 goto remove;
482 /* try harder only if disk space is low */
483 if (!low_disk_space)
484 goto out;
485 why = "orphaned";
486 victim = find_orphaned_snapshot(&sl);
487 if (victim)
488 goto remove;
489 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
490 victim = find_oldest_removable_snapshot(&sl);
491 if (victim)
492 goto remove;
493 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
494 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
495 goto out;
496 remove:
497 ret = pre_remove_hook(victim, why);
498 out:
499 free_snapshot_list(&sl);
500 return ret;
501 }
502
503 static int post_create_hook(void)
504 {
505 int ret, fds[3] = {0, 0, 0};
506 char *cmd;
507
508 if (!conf.post_create_hook_given) {
509 snapshot_creation_status = HS_READY;
510 return 0;
511 }
512 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
513 conf.dest_dir_arg, path_to_last_complete_snapshot);
514 DSS_NOTICE_LOG("executing %s\n", cmd);
515 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
516 free(cmd);
517 if (ret < 0)
518 return ret;
519 snapshot_creation_status = HS_POST_RUNNING;
520 return ret;
521 }
522
523 static int post_remove_hook(void)
524 {
525 int ret, fds[3] = {0, 0, 0};
526 char *cmd;
527 struct snapshot *s = snapshot_currently_being_removed;
528
529 assert(s);
530
531 if (!conf.post_remove_hook_given) {
532 snapshot_removal_status = HS_READY;
533 return 0;
534 }
535 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
536 conf.dest_dir_arg, s->name);
537 DSS_NOTICE_LOG("executing %s\n", cmd);
538 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
539 free(cmd);
540 if (ret < 0)
541 return ret;
542 snapshot_removal_status = HS_POST_RUNNING;
543 return ret;
544 }
545
546 static void kill_process(pid_t pid)
547 {
548 if (!pid)
549 return;
550 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
551 kill(pid, SIGTERM);
552 }
553
554 static void stop_create_process(void)
555 {
556 if (!create_pid || create_process_stopped)
557 return;
558 kill(SIGSTOP, create_pid);
559 create_process_stopped = 1;
560 }
561
562 static void restart_create_process(void)
563 {
564 if (!create_pid || !create_process_stopped)
565 return;
566 kill (SIGCONT, create_pid);
567 create_process_stopped = 0;
568 }
569
570 /**
571 * Print a log message about the exit status of a child.
572 */
573 static void log_termination_msg(pid_t pid, int status)
574 {
575 if (WIFEXITED(status))
576 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
577 WEXITSTATUS(status));
578 else if (WIFSIGNALED(status))
579 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
580 WTERMSIG(status));
581 else
582 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
583 }
584
585 static int wait_for_process(pid_t pid, int *status)
586 {
587 int ret;
588
589 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
590 for (;;) {
591 fd_set rfds;
592
593 FD_ZERO(&rfds);
594 FD_SET(signal_pipe, &rfds);
595 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
596 if (ret < 0)
597 break;
598 ret = next_signal();
599 if (!ret)
600 continue;
601 if (ret == SIGCHLD) {
602 ret = waitpid(pid, status, 0);
603 if (ret >= 0)
604 break;
605 if (errno != EINTR) { /* error */
606 ret = -ERRNO_TO_DSS_ERROR(errno);
607 break;
608 }
609 }
610 /* SIGINT or SIGTERM */
611 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
612 kill(pid, SIGTERM);
613 }
614 if (ret < 0)
615 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
616 else
617 log_termination_msg(pid, *status);
618 return ret;
619 }
620
621 static void handle_pre_remove_exit(int status)
622 {
623 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
624 snapshot_removal_status = HS_READY;
625 gettimeofday(&next_removal_check, NULL);
626 next_removal_check.tv_sec += 60;
627 return;
628 }
629 snapshot_removal_status = HS_PRE_SUCCESS;
630 }
631
632 static int handle_rm_exit(int status)
633 {
634 if (!WIFEXITED(status)) {
635 snapshot_removal_status = HS_READY;
636 return -E_INVOLUNTARY_EXIT;
637 }
638 if (WEXITSTATUS(status)) {
639 snapshot_removal_status = HS_READY;
640 return -E_BAD_EXIT_CODE;
641 }
642 if (conf.post_remove_hook_given)
643 snapshot_removal_status = HS_SUCCESS;
644 else
645 snapshot_removal_status = HS_READY;
646 return 1;
647 }
648
649 static void handle_post_remove_exit(void)
650 {
651 snapshot_removal_status = HS_READY;
652 }
653
654 static int handle_remove_exit(int status)
655 {
656 int ret;
657 struct snapshot *s = snapshot_currently_being_removed;
658
659 assert(s);
660 switch (snapshot_removal_status) {
661 case HS_PRE_RUNNING:
662 handle_pre_remove_exit(status);
663 ret = 1;
664 break;
665 case HS_RUNNING:
666 ret = handle_rm_exit(status);
667 break;
668 case HS_POST_RUNNING:
669 handle_post_remove_exit();
670 ret = 1;
671 break;
672 default:
673 ret = -E_BUG;
674 }
675 if (snapshot_removal_status == HS_READY) {
676 free(s->name);
677 free(s);
678 snapshot_currently_being_removed = NULL;
679 }
680 remove_pid = 0;
681 return ret;
682 }
683
684 static int wait_for_remove_process(void)
685 {
686 int status, ret;
687
688 assert(remove_pid);
689 assert(
690 snapshot_removal_status == HS_PRE_RUNNING ||
691 snapshot_removal_status == HS_RUNNING ||
692 snapshot_removal_status == HS_POST_RUNNING
693 );
694 ret = wait_for_process(remove_pid, &status);
695 if (ret < 0)
696 return ret;
697 return handle_remove_exit(status);
698 }
699
700 static int handle_rsync_exit(int status)
701 {
702 int es, ret;
703
704 if (!WIFEXITED(status)) {
705 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
706 ret = -E_INVOLUNTARY_EXIT;
707 snapshot_creation_status = HS_READY;
708 goto out;
709 }
710 es = WEXITSTATUS(status);
711 /*
712 * Restart rsync on non-fatal errors:
713 * 12: Error in rsync protocol data stream
714 * 13: Errors with program diagnostics
715 */
716 if (es == 12 || es == 13) {
717 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
718 (int)create_pid, es);
719 snapshot_creation_status = HS_NEEDS_RESTART;
720 next_snapshot_time = get_current_time() + 60;
721 ret = 1;
722 goto out;
723 }
724 if (es != 0 && es != 23 && es != 24) {
725 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
726 ret = -E_BAD_EXIT_CODE;
727 snapshot_creation_status = HS_READY;
728 goto out;
729 }
730 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
731 if (ret < 0)
732 goto out;
733 snapshot_creation_status = HS_SUCCESS;
734 free(name_of_reference_snapshot);
735 name_of_reference_snapshot = NULL;
736 out:
737 create_pid = 0;
738 create_process_stopped = 0;
739 return ret;
740 }
741
742 static int handle_pre_create_hook_exit(int status)
743 {
744 int es, ret;
745 static int warn_count;
746
747 if (!WIFEXITED(status)) {
748 snapshot_creation_status = HS_READY;
749 ret = -E_INVOLUNTARY_EXIT;
750 goto out;
751 }
752 es = WEXITSTATUS(status);
753 if (es) {
754 if (!warn_count--) {
755 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
756 conf.pre_create_hook_arg, es);
757 DSS_NOTICE_LOG("deferring snapshot creation...\n");
758 warn_count = 60; /* warn only once per hour */
759 }
760 next_snapshot_time = get_current_time() + 60;
761 snapshot_creation_status = HS_READY;
762 ret = 0;
763 goto out;
764 }
765 warn_count = 0;
766 snapshot_creation_status = HS_PRE_SUCCESS;
767 ret = 1;
768 out:
769 create_pid = 0;
770 return ret;
771 }
772
773 static int handle_sigchld(void)
774 {
775 pid_t pid;
776 int status, ret = reap_child(&pid, &status);
777
778 if (ret <= 0)
779 return ret;
780
781 if (pid == create_pid) {
782 switch (snapshot_creation_status) {
783 case HS_PRE_RUNNING:
784 return handle_pre_create_hook_exit(status);
785 case HS_RUNNING:
786 return handle_rsync_exit(status);
787 case HS_POST_RUNNING:
788 snapshot_creation_status = HS_READY;
789 return 1;
790 default:
791 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
792 snapshot_creation_status);
793 return -E_BUG;
794 }
795 }
796 if (pid == remove_pid) {
797 ret = handle_remove_exit(status);
798 if (ret < 0)
799 return ret;
800 return ret;
801 }
802 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
803 return -E_BUG;
804 }
805
806 static int check_config(void)
807 {
808 if (conf.unit_interval_arg <= 0) {
809 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
810 return -E_INVALID_NUMBER;
811 }
812 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
813 if (conf.num_intervals_arg <= 0) {
814 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
815 return -E_INVALID_NUMBER;
816 }
817 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
818 return 1;
819 }
820
821 static int parse_config_file(int override)
822 {
823 int ret;
824 char *config_file;
825 struct stat statbuf;
826 char *old_logfile_arg = NULL;
827 int old_daemon_given = 0;
828
829 if (conf.config_file_given)
830 config_file = dss_strdup(conf.config_file_arg);
831 else {
832 char *home = get_homedir();
833 config_file = make_message("%s/.dssrc", home);
834 free(home);
835 }
836 if (override) { /* SIGHUP */
837 if (conf.logfile_given)
838 old_logfile_arg = dss_strdup(conf.logfile_arg);
839 old_daemon_given = conf.daemon_given;
840 }
841
842 ret = stat(config_file, &statbuf);
843 if (ret && conf.config_file_given) {
844 ret = -ERRNO_TO_DSS_ERROR(errno);
845 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
846 goto out;
847 }
848 if (!ret) {
849 struct cmdline_parser_params params = {
850 .override = override,
851 .initialize = 0,
852 .check_required = 1,
853 .check_ambiguity = 0,
854 .print_errors = 1
855 };
856 if (override) { /* invalidate all rsync options */
857 int i;
858
859 for (i = 0; i < conf.rsync_option_given; i++) {
860 free(conf.rsync_option_arg[i]);
861 conf.rsync_option_arg[i] = NULL;
862 }
863 conf.rsync_option_given = 0;
864 }
865 cmdline_parser_config_file(config_file, &conf, &params);
866 }
867 ret = check_config();
868 if (ret < 0)
869 goto out;
870 if (override) {
871 /* don't change daemon mode on SIGHUP */
872 conf.daemon_given = old_daemon_given;
873 close_log(logfile);
874 logfile = NULL;
875 if (conf.logfile_given)
876 free(old_logfile_arg);
877 else if (conf.daemon_given) { /* re-use old logfile */
878 conf.logfile_arg = old_logfile_arg;
879 conf.logfile_given = 1;
880 }
881 }
882 if (conf.logfile_given) {
883 logfile = open_log(conf.logfile_arg);
884 log_welcome(conf.loglevel_arg);
885 }
886 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
887 // cmdline_parser_dump(logfile? logfile : stdout, &conf);
888 out:
889 free(config_file);
890 if (ret < 0)
891 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
892 return ret;
893 }
894
895 static int change_to_dest_dir(void)
896 {
897 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
898 return dss_chdir(conf.dest_dir_arg);
899 }
900
901 static int handle_sighup(void)
902 {
903 int ret;
904
905 DSS_NOTICE_LOG("SIGHUP\n");
906 ret = parse_config_file(1);
907 if (ret < 0)
908 return ret;
909 invalidate_next_snapshot_time();
910 return change_to_dest_dir();
911 }
912
913 static int handle_signal(void)
914 {
915 int sig, ret = next_signal();
916
917 if (ret <= 0)
918 goto out;
919 sig = ret;
920 switch (sig) {
921 case SIGINT:
922 case SIGTERM:
923 restart_create_process();
924 kill_process(create_pid);
925 kill_process(remove_pid);
926 ret = -E_SIGNAL;
927 break;
928 case SIGHUP:
929 ret = handle_sighup();
930 break;
931 case SIGCHLD:
932 ret = handle_sigchld();
933 break;
934 }
935 out:
936 if (ret < 0)
937 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
938 return ret;
939 }
940
941 /*
942 * We can not use rsync locally if the local user is different from the remote
943 * user or if the src dir is not on the local host (or both).
944 */
945 static int use_rsync_locally(char *logname)
946 {
947 char *h = conf.remote_host_arg;
948
949 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
950 return 0;
951 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
952 return 0;
953 return 1;
954 }
955
956 static void create_rsync_argv(char ***argv, int64_t *num)
957 {
958 char *logname;
959 int i = 0, j;
960 struct snapshot_list sl;
961
962 dss_get_snapshot_list(&sl);
963 assert(!name_of_reference_snapshot);
964 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
965 free_snapshot_list(&sl);
966
967 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
968 (*argv)[i++] = dss_strdup("rsync");
969 (*argv)[i++] = dss_strdup("-aq");
970 (*argv)[i++] = dss_strdup("--delete");
971 for (j = 0; j < conf.rsync_option_given; j++)
972 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
973 if (name_of_reference_snapshot) {
974 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
975 (*argv)[i++] = make_message("--link-dest=../%s",
976 name_of_reference_snapshot);
977 } else
978 DSS_INFO_LOG("no suitable reference snapshot found\n");
979 logname = dss_logname();
980 if (use_rsync_locally(logname))
981 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
982 else
983 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
984 conf.remote_user_arg : logname,
985 conf.remote_host_arg, conf.source_dir_arg);
986 free(logname);
987 *num = get_current_time();
988 (*argv)[i++] = incomplete_name(*num);
989 (*argv)[i++] = NULL;
990 for (j = 0; j < i; j++)
991 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
992 }
993
994 static void free_rsync_argv(char **argv)
995 {
996 int i;
997
998 if (!argv)
999 return;
1000 for (i = 0; argv[i]; i++)
1001 free(argv[i]);
1002 free(argv);
1003 }
1004
1005 static int create_snapshot(char **argv)
1006 {
1007 int ret, fds[3] = {0, 0, 0};
1008 char *name;
1009
1010 name = incomplete_name(current_snapshot_creation_time);
1011 DSS_NOTICE_LOG("creating new snapshot %s\n", name);
1012 free(name);
1013 ret = dss_exec(&create_pid, argv[0], argv, fds);
1014 if (ret < 0)
1015 return ret;
1016 snapshot_creation_status = HS_RUNNING;
1017 return ret;
1018 }
1019
1020 static int select_loop(void)
1021 {
1022 int ret;
1023 /* check every 60 seconds for free disk space */
1024 struct timeval tv;
1025 char **rsync_argv = NULL;
1026
1027 for (;;) {
1028 fd_set rfds;
1029 struct timeval *tvp;
1030
1031 if (remove_pid)
1032 tvp = NULL; /* sleep until rm hook/process dies */
1033 else { /* sleep one minute */
1034 tv.tv_sec = 60;
1035 tv.tv_usec = 0;
1036 tvp = &tv;
1037 }
1038 FD_ZERO(&rfds);
1039 FD_SET(signal_pipe, &rfds);
1040 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1041 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1042 if (ret < 0)
1043 goto out;
1044 if (FD_ISSET(signal_pipe, &rfds)) {
1045 ret = handle_signal();
1046 if (ret < 0)
1047 goto out;
1048 }
1049 if (remove_pid)
1050 continue;
1051 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1052 ret = exec_rm();
1053 if (ret < 0)
1054 goto out;
1055 continue;
1056 }
1057 if (snapshot_removal_status == HS_SUCCESS) {
1058 ret = post_remove_hook();
1059 if (ret < 0)
1060 goto out;
1061 continue;
1062 }
1063 ret = try_to_free_disk_space();
1064 if (ret < 0)
1065 goto out;
1066 if (snapshot_removal_status != HS_READY) {
1067 stop_create_process();
1068 continue;
1069 }
1070 restart_create_process();
1071 switch (snapshot_creation_status) {
1072 case HS_READY:
1073 if (!next_snapshot_is_due())
1074 continue;
1075 ret = pre_create_hook();
1076 if (ret < 0)
1077 goto out;
1078 continue;
1079 case HS_PRE_RUNNING:
1080 case HS_RUNNING:
1081 case HS_POST_RUNNING:
1082 continue;
1083 case HS_PRE_SUCCESS:
1084 free_rsync_argv(rsync_argv);
1085 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1086 /* fall through */
1087 case HS_NEEDS_RESTART:
1088 ret = create_snapshot(rsync_argv);
1089 if (ret < 0)
1090 goto out;
1091 continue;
1092 case HS_SUCCESS:
1093 ret = post_create_hook();
1094 if (ret < 0)
1095 goto out;
1096 continue;
1097 }
1098 }
1099 out:
1100 return ret;
1101 }
1102
1103 static void exit_hook(int exit_code)
1104 {
1105 int fds[3] = {0, 0, 0};
1106 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1107 pid_t pid;
1108
1109 if (!conf.exit_hook_given)
1110 return;
1111 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1112 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1113 }
1114
1115 static int com_run(void)
1116 {
1117 int ret;
1118
1119 if (conf.dry_run_given) {
1120 DSS_ERROR_LOG("dry_run not supported by this command\n");
1121 return -E_SYNTAX;
1122 }
1123 ret = install_sighandler(SIGHUP);
1124 if (ret < 0)
1125 return ret;
1126 ret = select_loop();
1127 if (ret >= 0) /* impossible */
1128 ret = -E_BUG;
1129 exit_hook(ret);
1130 return ret;
1131 }
1132
1133 static int com_prune(void)
1134 {
1135 int ret;
1136 struct snapshot_list sl;
1137 struct snapshot *victim;
1138 struct disk_space ds;
1139 const char *why;
1140
1141 ret = get_disk_space(".", &ds);
1142 if (ret < 0)
1143 return ret;
1144 log_disk_space(&ds);
1145 dss_get_snapshot_list(&sl);
1146 why = "outdated";
1147 victim = find_outdated_snapshot(&sl);
1148 if (victim)
1149 goto rm;
1150 why = "redundant";
1151 victim = find_redundant_snapshot(&sl);
1152 if (victim)
1153 goto rm;
1154 ret = 0;
1155 goto out;
1156 rm:
1157 if (conf.dry_run_given) {
1158 dss_msg("%s snapshot %s (interval = %i)\n",
1159 why, victim->name, victim->interval);
1160 ret = 0;
1161 goto out;
1162 }
1163 ret = pre_remove_hook(victim, why);
1164 if (ret < 0)
1165 goto out;
1166 if (snapshot_removal_status == HS_PRE_RUNNING) {
1167 ret = wait_for_remove_process();
1168 if (ret < 0)
1169 goto out;
1170 if (snapshot_removal_status != HS_PRE_SUCCESS)
1171 goto out;
1172 }
1173 ret = exec_rm();
1174 if (ret < 0)
1175 goto out;
1176 ret = wait_for_remove_process();
1177 if (ret < 0)
1178 goto out;
1179 if (snapshot_removal_status != HS_SUCCESS)
1180 goto out;
1181 ret = post_remove_hook();
1182 if (ret < 0)
1183 goto out;
1184 if (snapshot_removal_status != HS_POST_RUNNING)
1185 goto out;
1186 ret = wait_for_remove_process();
1187 if (ret < 0)
1188 goto out;
1189 ret = 1;
1190 out:
1191 free_snapshot_list(&sl);
1192 return ret;
1193 }
1194
1195 static int com_create(void)
1196 {
1197 int ret, status;
1198 char **rsync_argv;
1199
1200 if (conf.dry_run_given) {
1201 int i;
1202 char *msg = NULL;
1203 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1204 for (i = 0; rsync_argv[i]; i++) {
1205 char *tmp = msg;
1206 msg = make_message("%s%s%s", tmp? tmp : "",
1207 tmp? " " : "", rsync_argv[i]);
1208 free(tmp);
1209 }
1210 free_rsync_argv(rsync_argv);
1211 dss_msg("%s\n", msg);
1212 free(msg);
1213 return 1;
1214 }
1215 ret = pre_create_hook();
1216 if (ret < 0)
1217 return ret;
1218 if (create_pid) {
1219 ret = wait_for_process(create_pid, &status);
1220 if (ret < 0)
1221 return ret;
1222 ret = handle_pre_create_hook_exit(status);
1223 if (ret <= 0) /* error, or pre-create failed */
1224 return ret;
1225 }
1226 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1227 ret = create_snapshot(rsync_argv);
1228 if (ret < 0)
1229 goto out;
1230 ret = wait_for_process(create_pid, &status);
1231 if (ret < 0)
1232 goto out;
1233 ret = handle_rsync_exit(status);
1234 if (ret < 0)
1235 goto out;
1236 post_create_hook();
1237 if (create_pid)
1238 ret = wait_for_process(create_pid, &status);
1239 out:
1240 free_rsync_argv(rsync_argv);
1241 return ret;
1242 }
1243
1244 static int com_ls(void)
1245 {
1246 int i;
1247 struct snapshot_list sl;
1248 struct snapshot *s;
1249
1250 dss_get_snapshot_list(&sl);
1251 FOR_EACH_SNAPSHOT(s, i, &sl) {
1252 int64_t d = 0;
1253 if (s->flags & SS_COMPLETE)
1254 d = (s->completion_time - s->creation_time) / 60;
1255 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1256 };
1257 free_snapshot_list(&sl);
1258 return 1;
1259 }
1260
1261 static int setup_signal_handling(void)
1262 {
1263 int ret;
1264
1265 DSS_INFO_LOG("setting up signal handlers\n");
1266 signal_pipe = signal_init(); /* always successful */
1267 ret = install_sighandler(SIGINT);
1268 if (ret < 0)
1269 return ret;
1270 ret = install_sighandler(SIGTERM);
1271 if (ret < 0)
1272 return ret;
1273 return install_sighandler(SIGCHLD);
1274 }
1275
1276 /**
1277 * The main function of dss.
1278 *
1279 * \param argc Usual argument count.
1280 * \param argv Usual argument vector.
1281 */
1282 int main(int argc, char **argv)
1283 {
1284 int ret;
1285 struct cmdline_parser_params params = {
1286 .override = 0,
1287 .initialize = 1,
1288 .check_required = 0,
1289 .check_ambiguity = 0,
1290 .print_errors = 1
1291 };
1292
1293 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1294 ret = parse_config_file(0);
1295 if (ret < 0)
1296 goto out;
1297 if (conf.daemon_given)
1298 daemon_init();
1299 ret = change_to_dest_dir();
1300 if (ret < 0)
1301 goto out;
1302 ret = setup_signal_handling();
1303 if (ret < 0)
1304 goto out;
1305 ret = call_command_handler();
1306 out:
1307 if (ret < 0)
1308 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1309 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1310 }