pre_remove_hook: Really pass full path of the snapshot.
[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 dss_get_snapshot_list(&sl);
165 FOR_EACH_SNAPSHOT(s, i, &sl) {
166 if (!(s->flags & SS_COMPLETE))
167 continue;
168 num_complete_snapshots++;
169 x += s->completion_time - s->creation_time;
170 }
171 assert(x >= 0);
172
173 ret = now;
174 if (num_complete_snapshots == 0)
175 goto out;
176 x /= num_complete_snapshots; /* avg time to create one snapshot */
177 if (unit_interval < x * wanted) /* oops, no sleep at all */
178 goto out;
179 ret = s->completion_time + unit_interval / wanted - x;
180 out:
181 free_snapshot_list(&sl);
182 return ret;
183 }
184
185 static inline void invalidate_next_snapshot_time(void)
186 {
187 next_snapshot_time = 0;
188 }
189
190 static inline int next_snapshot_time_is_valid(void)
191 {
192 return next_snapshot_time != 0;
193 }
194
195 static int next_snapshot_is_due(void)
196 {
197 int64_t now = get_current_time();
198
199 if (!next_snapshot_time_is_valid())
200 next_snapshot_time = compute_next_snapshot_time();
201 if (next_snapshot_time <= now) {
202 DSS_DEBUG_LOG("next snapshot: now\n");
203 return 1;
204 }
205 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
206 next_snapshot_time - now);
207 return 0;
208 }
209
210 static int pre_create_hook(void)
211 {
212 int ret, fds[3] = {0, 0, 0};
213
214 assert(snapshot_creation_status == HS_READY);
215 /* make sure that the next snapshot time will be recomputed */
216 invalidate_next_snapshot_time();
217 if (!conf.pre_create_hook_given) {
218 snapshot_creation_status = HS_PRE_SUCCESS;
219 return 0;
220 }
221 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
222 ret = dss_exec_cmdline_pid(&create_pid,
223 conf.pre_create_hook_arg, fds);
224 if (ret < 0)
225 return ret;
226 snapshot_creation_status = HS_PRE_RUNNING;
227 return ret;
228 }
229
230 static int pre_remove_hook(struct snapshot *s, const char *why)
231 {
232 int ret, fds[3] = {0, 0, 0};
233 char *cmd;
234
235 if (!s)
236 return 0;
237 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
238 assert(snapshot_removal_status == HS_READY);
239 assert(remove_pid == 0);
240 assert(!snapshot_currently_being_removed);
241
242 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
243 *snapshot_currently_being_removed = *s;
244 snapshot_currently_being_removed->name = dss_strdup(s->name);
245
246 if (!conf.pre_remove_hook_given) {
247 snapshot_removal_status = HS_PRE_SUCCESS;
248 return 0;
249 }
250 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
251 conf.dest_dir_arg, s->name);
252 DSS_DEBUG_LOG("executing %s\n", cmd);
253 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
254 free(cmd);
255 if (ret < 0)
256 return ret;
257 snapshot_removal_status = HS_PRE_RUNNING;
258 return ret;
259 }
260
261 static int exec_rm(void)
262 {
263 struct snapshot *s = snapshot_currently_being_removed;
264 int fds[3] = {0, 0, 0};
265 char *new_name = being_deleted_name(s);
266 char *argv[] = {"rm", "-rf", new_name, NULL};
267 int ret;
268
269 assert(snapshot_removal_status == HS_PRE_SUCCESS);
270 assert(remove_pid == 0);
271
272 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
273 ret = dss_rename(s->name, new_name);
274 if (ret < 0)
275 goto out;
276 ret = dss_exec(&remove_pid, argv[0], argv, fds);
277 if (ret < 0)
278 goto out;
279 snapshot_removal_status = HS_RUNNING;
280 out:
281 free(new_name);
282 return ret;
283 }
284
285 static int snapshot_is_being_created(struct snapshot *s)
286 {
287 return s->creation_time == current_snapshot_creation_time;
288 }
289
290 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
291 {
292 struct snapshot *s;
293 int i;
294
295 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
296 FOR_EACH_SNAPSHOT(s, i, sl) {
297 if (snapshot_is_being_created(s))
298 continue;
299 /*
300 * We know that no rm is currently running, so if s is marked
301 * as being deleted, a previously started rm must have failed.
302 */
303 if (s->flags & SS_BEING_DELETED)
304 return s;
305
306 if (s->flags & SS_COMPLETE) /* good snapshot */
307 continue;
308 /*
309 * This snapshot is incomplete and it is not the snapshot
310 * currently being created. However, we must not remove it if
311 * rsync is about to be restarted. As only the newest snapshot
312 * can be restarted, this snapshot is orphaned if it is not the
313 * newest snapshot or if we are not about to restart rsync.
314 */
315 if (get_newest_snapshot(sl) != s)
316 return s;
317 if (snapshot_creation_status != HS_NEEDS_RESTART)
318 return s;
319 }
320 /* no orphaned snapshots */
321 return NULL;
322 }
323
324 static int is_reference_snapshot(struct snapshot *s)
325 {
326 if (!name_of_reference_snapshot)
327 return 0;
328 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
329 }
330
331 /*
332 * return: 0: no redundant snapshots, 1: rm process started, negative: error
333 */
334 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
335 {
336 int i, interval;
337 struct snapshot *s;
338 unsigned missing = 0;
339
340 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
341 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
342 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
343 unsigned num = sl->interval_count[interval];
344 struct snapshot *victim = NULL, *prev = NULL;
345 int64_t score = LONG_MAX;
346
347 if (keep >= num)
348 missing += keep - num;
349 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
350 // interval, keep, num, missing);
351 if (keep + missing >= num)
352 continue;
353 /* redundant snapshot in this interval, pick snapshot with lowest score */
354 FOR_EACH_SNAPSHOT(s, i, sl) {
355 int64_t this_score;
356
357 if (snapshot_is_being_created(s))
358 continue;
359 if (is_reference_snapshot(s))
360 continue;
361 //DSS_DEBUG_LOG("checking %s\n", s->name);
362 if (s->interval > interval) {
363 prev = s;
364 continue;
365 }
366 if (s->interval < interval)
367 break;
368 if (!victim) {
369 victim = s;
370 prev = s;
371 continue;
372 }
373 assert(prev);
374 /* check if s is a better victim */
375 this_score = s->creation_time - prev->creation_time;
376 assert(this_score >= 0);
377 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
378 if (this_score < score) {
379 score = this_score;
380 victim = s;
381 }
382 prev = s;
383 }
384 assert(victim);
385 return victim;
386 }
387 return NULL;
388 }
389
390 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
391 {
392 int i;
393 struct snapshot *s;
394
395 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
396 conf.num_intervals_arg);
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 if (s->interval < conf.num_intervals_arg)
403 continue;
404 return s;
405 }
406 return NULL;
407 }
408
409 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
410 {
411 int i;
412 struct snapshot *s;
413 FOR_EACH_SNAPSHOT(s, i, sl) {
414 if (snapshot_is_being_created(s))
415 continue;
416 if (is_reference_snapshot(s))
417 continue;
418 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
419 return s;
420 }
421 return NULL;
422 }
423
424 static int rename_incomplete_snapshot(int64_t start)
425 {
426 char *old_name;
427 int ret;
428
429 free(path_to_last_complete_snapshot);
430 ret = complete_name(start, get_current_time(),
431 &path_to_last_complete_snapshot);
432 if (ret < 0)
433 return ret;
434 old_name = incomplete_name(start);
435 ret = dss_rename(old_name, path_to_last_complete_snapshot);
436 if (ret >= 0)
437 DSS_NOTICE_LOG("%s -> %s\n", old_name,
438 path_to_last_complete_snapshot);
439 free(old_name);
440 return ret;
441 }
442
443 static int try_to_free_disk_space(void)
444 {
445 int ret;
446 struct snapshot_list sl;
447 struct snapshot *victim;
448 struct timeval now;
449 const char *why;
450 int low_disk_space;
451
452 ret = disk_space_low();
453 if (ret < 0)
454 return ret;
455 low_disk_space = ret;
456 gettimeofday(&now, NULL);
457 if (tv_diff(&next_removal_check, &now, NULL) > 0)
458 return 0;
459 if (!low_disk_space) {
460 if (conf.keep_redundant_given)
461 return 0;
462 if (snapshot_creation_status != HS_READY)
463 return 0;
464 if (next_snapshot_is_due())
465 return 0;
466 }
467 dss_get_snapshot_list(&sl);
468 ret = 0;
469 if (!low_disk_space && sl.num_snapshots <= 1)
470 goto out;
471 why = "outdated";
472 victim = find_outdated_snapshot(&sl);
473 if (victim)
474 goto remove;
475 why = "redundant";
476 victim = find_redundant_snapshot(&sl);
477 if (victim)
478 goto remove;
479 /* try harder only if disk space is low */
480 if (!low_disk_space)
481 goto out;
482 why = "orphaned";
483 victim = find_orphaned_snapshot(&sl);
484 if (victim)
485 goto remove;
486 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
487 victim = find_oldest_removable_snapshot(&sl);
488 if (victim)
489 goto remove;
490 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
491 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
492 goto out;
493 remove:
494 ret = pre_remove_hook(victim, why);
495 out:
496 free_snapshot_list(&sl);
497 return ret;
498 }
499
500 static int post_create_hook(void)
501 {
502 int ret, fds[3] = {0, 0, 0};
503 char *cmd;
504
505 if (!conf.post_create_hook_given) {
506 create_pid = 0;
507 snapshot_creation_status = HS_READY;
508 return 0;
509 }
510 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
511 conf.dest_dir_arg, path_to_last_complete_snapshot);
512 DSS_NOTICE_LOG("executing %s\n", cmd);
513 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
514 free(cmd);
515 if (ret < 0)
516 return ret;
517 snapshot_creation_status = HS_POST_RUNNING;
518 return ret;
519 }
520
521 static int post_remove_hook(void)
522 {
523 int ret, fds[3] = {0, 0, 0};
524 char *cmd;
525 struct snapshot *s = snapshot_currently_being_removed;
526
527 assert(s);
528
529 if (!conf.post_remove_hook_given) {
530 snapshot_removal_status = HS_READY;
531 return 0;
532 }
533 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
534 conf.dest_dir_arg, s->name);
535 DSS_NOTICE_LOG("executing %s\n", cmd);
536 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
537 free(cmd);
538 if (ret < 0)
539 return ret;
540 snapshot_removal_status = HS_POST_RUNNING;
541 return ret;
542 }
543
544 static void kill_process(pid_t pid)
545 {
546 if (!pid)
547 return;
548 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
549 kill(pid, SIGTERM);
550 }
551
552 static void stop_create_process(void)
553 {
554 if (!create_pid || create_process_stopped)
555 return;
556 kill(SIGSTOP, create_pid);
557 create_process_stopped = 1;
558 }
559
560 static void restart_create_process(void)
561 {
562 if (!create_pid || !create_process_stopped)
563 return;
564 kill (SIGCONT, create_pid);
565 create_process_stopped = 0;
566 }
567
568 /**
569 * Print a log message about the exit status of a child.
570 */
571 static void log_termination_msg(pid_t pid, int status)
572 {
573 if (WIFEXITED(status))
574 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
575 WEXITSTATUS(status));
576 else if (WIFSIGNALED(status))
577 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
578 WTERMSIG(status));
579 else
580 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
581 }
582
583 static int wait_for_process(pid_t pid, int *status)
584 {
585 int ret;
586
587 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
588 for (;;) {
589 fd_set rfds;
590
591 FD_ZERO(&rfds);
592 FD_SET(signal_pipe, &rfds);
593 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
594 if (ret < 0)
595 break;
596 ret = next_signal();
597 if (!ret)
598 continue;
599 if (ret == SIGCHLD) {
600 ret = waitpid(pid, status, 0);
601 if (ret >= 0)
602 break;
603 if (errno != EINTR) { /* error */
604 ret = -ERRNO_TO_DSS_ERROR(errno);
605 break;
606 }
607 }
608 /* SIGINT or SIGTERM */
609 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
610 kill(pid, SIGTERM);
611 }
612 if (ret < 0)
613 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
614 else
615 log_termination_msg(pid, *status);
616 return ret;
617 }
618
619 static void handle_pre_remove_exit(int status)
620 {
621 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
622 snapshot_removal_status = HS_READY;
623 gettimeofday(&next_removal_check, NULL);
624 next_removal_check.tv_sec += 60;
625 return;
626 }
627 snapshot_removal_status = HS_PRE_SUCCESS;
628 }
629
630 static int handle_rm_exit(int status)
631 {
632 if (!WIFEXITED(status)) {
633 snapshot_removal_status = HS_READY;
634 return -E_INVOLUNTARY_EXIT;
635 }
636 if (WEXITSTATUS(status)) {
637 snapshot_removal_status = HS_READY;
638 return -E_BAD_EXIT_CODE;
639 }
640 if (conf.post_remove_hook_given)
641 snapshot_removal_status = HS_SUCCESS;
642 else
643 snapshot_removal_status = HS_READY;
644 return 1;
645 }
646
647 static void handle_post_remove_exit(void)
648 {
649 snapshot_removal_status = HS_READY;
650 }
651
652 static int handle_remove_exit(int status)
653 {
654 int ret;
655 struct snapshot *s = snapshot_currently_being_removed;
656
657 assert(s);
658 switch (snapshot_removal_status) {
659 case HS_PRE_RUNNING:
660 handle_pre_remove_exit(status);
661 ret = 1;
662 break;
663 case HS_RUNNING:
664 ret = handle_rm_exit(status);
665 break;
666 case HS_POST_RUNNING:
667 handle_post_remove_exit();
668 ret = 1;
669 break;
670 default:
671 ret = -E_BUG;
672 }
673 if (snapshot_removal_status == HS_READY) {
674 free(s->name);
675 free(s);
676 snapshot_currently_being_removed = NULL;
677 }
678 remove_pid = 0;
679 return ret;
680 }
681
682 static int wait_for_remove_process(void)
683 {
684 int status, ret;
685
686 assert(remove_pid);
687 assert(
688 snapshot_removal_status == HS_PRE_RUNNING ||
689 snapshot_removal_status == HS_RUNNING ||
690 snapshot_removal_status == HS_POST_RUNNING
691 );
692 ret = wait_for_process(remove_pid, &status);
693 if (ret < 0)
694 return ret;
695 return handle_remove_exit(status);
696 }
697
698 static int handle_rsync_exit(int status)
699 {
700 int es, ret;
701
702 if (!WIFEXITED(status)) {
703 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
704 ret = -E_INVOLUNTARY_EXIT;
705 snapshot_creation_status = HS_READY;
706 goto out;
707 }
708 es = WEXITSTATUS(status);
709 /*
710 * Restart rsync on non-fatal errors:
711 * 12: Error in rsync protocol data stream
712 * 13: Errors with program diagnostics
713 */
714 if (es == 12 || es == 13) {
715 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
716 (int)create_pid, es);
717 snapshot_creation_status = HS_NEEDS_RESTART;
718 next_snapshot_time = get_current_time() + 60;
719 ret = 1;
720 goto out;
721 }
722 if (es != 0 && es != 23 && es != 24) {
723 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
724 ret = -E_BAD_EXIT_CODE;
725 snapshot_creation_status = HS_READY;
726 goto out;
727 }
728 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
729 if (ret < 0)
730 goto out;
731 snapshot_creation_status = HS_SUCCESS;
732 free(name_of_reference_snapshot);
733 name_of_reference_snapshot = NULL;
734 out:
735 create_process_stopped = 0;
736 return ret;
737 }
738
739 static int handle_pre_create_hook_exit(int status)
740 {
741 int es, ret;
742 static int warn_count;
743
744 if (!WIFEXITED(status)) {
745 snapshot_creation_status = HS_READY;
746 ret = -E_INVOLUNTARY_EXIT;
747 goto out;
748 }
749 es = WEXITSTATUS(status);
750 if (es) {
751 if (!warn_count--) {
752 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
753 conf.pre_create_hook_arg, es);
754 DSS_NOTICE_LOG("deferring snapshot creation...\n");
755 warn_count = 60; /* warn only once per hour */
756 }
757 next_snapshot_time = get_current_time() + 60;
758 snapshot_creation_status = HS_READY;
759 ret = 0;
760 goto out;
761 }
762 warn_count = 0;
763 snapshot_creation_status = HS_PRE_SUCCESS;
764 ret = 1;
765 out:
766 return ret;
767 }
768
769 static int handle_sigchld(void)
770 {
771 pid_t pid;
772 int status, ret = reap_child(&pid, &status);
773
774 if (ret <= 0)
775 return ret;
776
777 if (pid == create_pid) {
778 switch (snapshot_creation_status) {
779 case HS_PRE_RUNNING:
780 return handle_pre_create_hook_exit(status);
781 case HS_RUNNING:
782 return handle_rsync_exit(status);
783 case HS_POST_RUNNING:
784 snapshot_creation_status = HS_READY;
785 return 1;
786 default:
787 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
788 snapshot_creation_status);
789 return -E_BUG;
790 }
791 create_pid = 0;
792 }
793 if (pid == remove_pid) {
794 ret = handle_remove_exit(status);
795 if (ret < 0)
796 return ret;
797 return ret;
798 }
799 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
800 return -E_BUG;
801 }
802
803 static int check_config(void)
804 {
805 if (conf.unit_interval_arg <= 0) {
806 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
807 return -E_INVALID_NUMBER;
808 }
809 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
810 if (conf.num_intervals_arg <= 0) {
811 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
812 return -E_INVALID_NUMBER;
813 }
814 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
815 return 1;
816 }
817
818 /*
819 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
820 * file was read successfully.
821 */
822 static int parse_config_file(int override)
823 {
824 int ret, config_file_exists;
825 char *config_file;
826 struct stat statbuf;
827 char *old_logfile_arg = NULL;
828 int old_daemon_given = 0;
829
830 if (conf.config_file_given)
831 config_file = dss_strdup(conf.config_file_arg);
832 else {
833 char *home = get_homedir();
834 config_file = make_message("%s/.dssrc", home);
835 free(home);
836 }
837 if (override) { /* SIGHUP */
838 if (conf.logfile_given)
839 old_logfile_arg = dss_strdup(conf.logfile_arg);
840 old_daemon_given = conf.daemon_given;
841 }
842
843 config_file_exists = !stat(config_file, &statbuf);
844 if (!config_file_exists && conf.config_file_given) {
845 ret = -ERRNO_TO_DSS_ERROR(errno);
846 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
847 goto out;
848 }
849 if (config_file_exists) {
850 struct cmdline_parser_params params = {
851 .override = override,
852 .initialize = 0,
853 .check_required = 1,
854 .check_ambiguity = 0,
855 .print_errors = 1
856 };
857 if (override) { /* invalidate all rsync options */
858 int i;
859
860 for (i = 0; i < conf.rsync_option_given; i++) {
861 free(conf.rsync_option_arg[i]);
862 conf.rsync_option_arg[i] = NULL;
863 }
864 conf.rsync_option_given = 0;
865 }
866 cmdline_parser_config_file(config_file, &conf, &params);
867 }
868 ret = check_config();
869 if (ret < 0)
870 goto out;
871 if (override) {
872 /* don't change daemon mode on SIGHUP */
873 conf.daemon_given = old_daemon_given;
874 close_log(logfile);
875 logfile = NULL;
876 if (conf.logfile_given)
877 free(old_logfile_arg);
878 else if (conf.daemon_given) { /* re-use old logfile */
879 conf.logfile_arg = old_logfile_arg;
880 conf.logfile_given = 1;
881 }
882 }
883 if (conf.logfile_given) {
884 logfile = open_log(conf.logfile_arg);
885 log_welcome(conf.loglevel_arg);
886 }
887 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
888 ret = config_file_exists;
889 out:
890 free(config_file);
891 if (ret < 0)
892 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
893 return ret;
894 }
895
896 static int change_to_dest_dir(void)
897 {
898 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
899 return dss_chdir(conf.dest_dir_arg);
900 }
901
902 static void dump_dss_config(const char *msg)
903 {
904 if (conf.loglevel_arg > INFO)
905 return;
906 DSS_INFO_LOG("%s\n", msg);
907 cmdline_parser_dump(logfile? logfile : stderr, &conf);
908 }
909
910 static int handle_sighup(void)
911 {
912 int ret;
913
914 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
915 dump_dss_config("current config");
916 ret = parse_config_file(1);
917 if (ret < 0)
918 return ret;
919 dump_dss_config("new config");
920 invalidate_next_snapshot_time();
921 return change_to_dest_dir();
922 }
923
924 static int handle_signal(void)
925 {
926 int sig, ret = next_signal();
927
928 if (ret <= 0)
929 goto out;
930 sig = ret;
931 switch (sig) {
932 case SIGINT:
933 case SIGTERM:
934 restart_create_process();
935 kill_process(create_pid);
936 kill_process(remove_pid);
937 ret = -E_SIGNAL;
938 break;
939 case SIGHUP:
940 ret = handle_sighup();
941 break;
942 case SIGCHLD:
943 ret = handle_sigchld();
944 break;
945 }
946 out:
947 if (ret < 0)
948 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
949 return ret;
950 }
951
952 /*
953 * We can not use rsync locally if the local user is different from the remote
954 * user or if the src dir is not on the local host (or both).
955 */
956 static int use_rsync_locally(char *logname)
957 {
958 char *h = conf.remote_host_arg;
959
960 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
961 return 0;
962 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
963 return 0;
964 return 1;
965 }
966
967 static int rename_resume_snap(int64_t creation_time)
968 {
969 struct snapshot_list sl = {.num_snapshots = 0};
970 struct snapshot *s;
971 char *new_name = incomplete_name(creation_time);
972 int ret;
973
974 ret = 0;
975 if (conf.no_resume_given)
976 goto out;
977 dss_get_snapshot_list(&sl);
978 s = get_newest_snapshot(&sl);
979 if (!s)
980 goto out;
981 if ((s->flags & SS_COMPLETE) != 0) /* complete */
982 goto out;
983 DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
984 ret = dss_rename(s->name, new_name);
985 out:
986 if (ret >= 0)
987 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
988 free(new_name);
989 free_snapshot_list(&sl);
990 return ret;
991 }
992
993 static void create_rsync_argv(char ***argv, int64_t *num)
994 {
995 char *logname;
996 int i = 0, j;
997 struct snapshot_list sl;
998
999 dss_get_snapshot_list(&sl);
1000 assert(!name_of_reference_snapshot);
1001 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1002 free_snapshot_list(&sl);
1003
1004 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1005 (*argv)[i++] = dss_strdup("rsync");
1006 (*argv)[i++] = dss_strdup("-aq");
1007 (*argv)[i++] = dss_strdup("--delete");
1008 for (j = 0; j < conf.rsync_option_given; j++)
1009 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1010 if (name_of_reference_snapshot) {
1011 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1012 (*argv)[i++] = make_message("--link-dest=../%s",
1013 name_of_reference_snapshot);
1014 } else
1015 DSS_INFO_LOG("no suitable reference snapshot found\n");
1016 logname = dss_logname();
1017 if (use_rsync_locally(logname))
1018 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1019 else
1020 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1021 conf.remote_user_arg : logname,
1022 conf.remote_host_arg, conf.source_dir_arg);
1023 free(logname);
1024 *num = get_current_time();
1025 (*argv)[i++] = incomplete_name(*num);
1026 (*argv)[i++] = NULL;
1027 for (j = 0; j < i; j++)
1028 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1029 }
1030
1031 static void free_rsync_argv(char **argv)
1032 {
1033 int i;
1034
1035 if (!argv)
1036 return;
1037 for (i = 0; argv[i]; i++)
1038 free(argv[i]);
1039 free(argv);
1040 }
1041
1042 static int create_snapshot(char **argv)
1043 {
1044 int ret, fds[3] = {0, 0, 0};
1045
1046 ret = rename_resume_snap(current_snapshot_creation_time);
1047 if (ret < 0)
1048 return ret;
1049 ret = dss_exec(&create_pid, argv[0], argv, fds);
1050 if (ret < 0)
1051 return ret;
1052 snapshot_creation_status = HS_RUNNING;
1053 return ret;
1054 }
1055
1056 static int select_loop(void)
1057 {
1058 int ret;
1059 /* check every 60 seconds for free disk space */
1060 struct timeval tv;
1061 char **rsync_argv = NULL;
1062
1063 for (;;) {
1064 fd_set rfds;
1065 struct timeval *tvp;
1066
1067 if (remove_pid)
1068 tvp = NULL; /* sleep until rm hook/process dies */
1069 else { /* sleep one minute */
1070 tv.tv_sec = 60;
1071 tv.tv_usec = 0;
1072 tvp = &tv;
1073 }
1074 FD_ZERO(&rfds);
1075 FD_SET(signal_pipe, &rfds);
1076 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1077 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1078 if (ret < 0)
1079 goto out;
1080 if (FD_ISSET(signal_pipe, &rfds)) {
1081 ret = handle_signal();
1082 if (ret < 0)
1083 goto out;
1084 }
1085 if (remove_pid)
1086 continue;
1087 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1088 ret = exec_rm();
1089 if (ret < 0)
1090 goto out;
1091 continue;
1092 }
1093 if (snapshot_removal_status == HS_SUCCESS) {
1094 ret = post_remove_hook();
1095 if (ret < 0)
1096 goto out;
1097 continue;
1098 }
1099 ret = try_to_free_disk_space();
1100 if (ret < 0)
1101 goto out;
1102 if (snapshot_removal_status != HS_READY) {
1103 stop_create_process();
1104 continue;
1105 }
1106 restart_create_process();
1107 switch (snapshot_creation_status) {
1108 case HS_READY:
1109 if (!next_snapshot_is_due())
1110 continue;
1111 ret = pre_create_hook();
1112 if (ret < 0)
1113 goto out;
1114 continue;
1115 case HS_PRE_RUNNING:
1116 case HS_RUNNING:
1117 case HS_POST_RUNNING:
1118 continue;
1119 case HS_PRE_SUCCESS:
1120 if (!name_of_reference_snapshot) {
1121 free_rsync_argv(rsync_argv);
1122 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1123 }
1124 /* fall through */
1125 case HS_NEEDS_RESTART:
1126 if (!next_snapshot_is_due())
1127 continue;
1128 ret = create_snapshot(rsync_argv);
1129 if (ret < 0)
1130 goto out;
1131 continue;
1132 case HS_SUCCESS:
1133 ret = post_create_hook();
1134 if (ret < 0)
1135 goto out;
1136 continue;
1137 }
1138 }
1139 out:
1140 return ret;
1141 }
1142
1143 static void exit_hook(int exit_code)
1144 {
1145 int fds[3] = {0, 0, 0};
1146 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1147 pid_t pid;
1148
1149 if (!conf.exit_hook_given)
1150 return;
1151 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1152 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1153 }
1154
1155 static int com_run(void)
1156 {
1157 int ret;
1158
1159 if (conf.dry_run_given) {
1160 DSS_ERROR_LOG("dry_run not supported by this command\n");
1161 return -E_SYNTAX;
1162 }
1163 ret = install_sighandler(SIGHUP);
1164 if (ret < 0)
1165 return ret;
1166 ret = select_loop();
1167 if (ret >= 0) /* impossible */
1168 ret = -E_BUG;
1169 exit_hook(ret);
1170 return ret;
1171 }
1172
1173 static int com_prune(void)
1174 {
1175 int ret;
1176 struct snapshot_list sl;
1177 struct snapshot *victim;
1178 struct disk_space ds;
1179 const char *why;
1180
1181 ret = get_disk_space(".", &ds);
1182 if (ret < 0)
1183 return ret;
1184 log_disk_space(&ds);
1185 dss_get_snapshot_list(&sl);
1186 why = "outdated";
1187 victim = find_outdated_snapshot(&sl);
1188 if (victim)
1189 goto rm;
1190 why = "redundant";
1191 victim = find_redundant_snapshot(&sl);
1192 if (victim)
1193 goto rm;
1194 ret = 0;
1195 goto out;
1196 rm:
1197 if (conf.dry_run_given) {
1198 dss_msg("%s snapshot %s (interval = %i)\n",
1199 why, victim->name, victim->interval);
1200 ret = 0;
1201 goto out;
1202 }
1203 ret = pre_remove_hook(victim, why);
1204 if (ret < 0)
1205 goto out;
1206 if (snapshot_removal_status == HS_PRE_RUNNING) {
1207 ret = wait_for_remove_process();
1208 if (ret < 0)
1209 goto out;
1210 if (snapshot_removal_status != HS_PRE_SUCCESS)
1211 goto out;
1212 }
1213 ret = exec_rm();
1214 if (ret < 0)
1215 goto out;
1216 ret = wait_for_remove_process();
1217 if (ret < 0)
1218 goto out;
1219 if (snapshot_removal_status != HS_SUCCESS)
1220 goto out;
1221 ret = post_remove_hook();
1222 if (ret < 0)
1223 goto out;
1224 if (snapshot_removal_status != HS_POST_RUNNING)
1225 goto out;
1226 ret = wait_for_remove_process();
1227 if (ret < 0)
1228 goto out;
1229 ret = 1;
1230 out:
1231 free_snapshot_list(&sl);
1232 return ret;
1233 }
1234
1235 static int com_create(void)
1236 {
1237 int ret, status;
1238 char **rsync_argv;
1239
1240 if (conf.dry_run_given) {
1241 int i;
1242 char *msg = NULL;
1243 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1244 for (i = 0; rsync_argv[i]; i++) {
1245 char *tmp = msg;
1246 msg = make_message("%s%s%s", tmp? tmp : "",
1247 tmp? " " : "", rsync_argv[i]);
1248 free(tmp);
1249 }
1250 free_rsync_argv(rsync_argv);
1251 dss_msg("%s\n", msg);
1252 free(msg);
1253 return 1;
1254 }
1255 ret = pre_create_hook();
1256 if (ret < 0)
1257 return ret;
1258 if (create_pid) {
1259 ret = wait_for_process(create_pid, &status);
1260 if (ret < 0)
1261 return ret;
1262 ret = handle_pre_create_hook_exit(status);
1263 if (ret <= 0) /* error, or pre-create failed */
1264 return ret;
1265 }
1266 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1267 ret = create_snapshot(rsync_argv);
1268 if (ret < 0)
1269 goto out;
1270 ret = wait_for_process(create_pid, &status);
1271 if (ret < 0)
1272 goto out;
1273 ret = handle_rsync_exit(status);
1274 if (ret < 0)
1275 goto out;
1276 post_create_hook();
1277 if (create_pid)
1278 ret = wait_for_process(create_pid, &status);
1279 out:
1280 free_rsync_argv(rsync_argv);
1281 return ret;
1282 }
1283
1284 static int com_ls(void)
1285 {
1286 int i;
1287 struct snapshot_list sl;
1288 struct snapshot *s;
1289
1290 dss_get_snapshot_list(&sl);
1291 FOR_EACH_SNAPSHOT(s, i, &sl) {
1292 int64_t d = 0;
1293 if (s->flags & SS_COMPLETE)
1294 d = (s->completion_time - s->creation_time) / 60;
1295 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1296 };
1297 free_snapshot_list(&sl);
1298 return 1;
1299 }
1300
1301 static int setup_signal_handling(void)
1302 {
1303 int ret;
1304
1305 DSS_INFO_LOG("setting up signal handlers\n");
1306 signal_pipe = signal_init(); /* always successful */
1307 ret = install_sighandler(SIGINT);
1308 if (ret < 0)
1309 return ret;
1310 ret = install_sighandler(SIGTERM);
1311 if (ret < 0)
1312 return ret;
1313 return install_sighandler(SIGCHLD);
1314 }
1315
1316 /**
1317 * The main function of dss.
1318 *
1319 * \param argc Usual argument count.
1320 * \param argv Usual argument vector.
1321 */
1322 int main(int argc, char **argv)
1323 {
1324 int ret;
1325 struct cmdline_parser_params params = {
1326 .override = 0,
1327 .initialize = 1,
1328 .check_required = 0,
1329 .check_ambiguity = 0,
1330 .print_errors = 1
1331 };
1332
1333 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1334 ret = parse_config_file(0);
1335 if (ret < 0)
1336 goto out;
1337 if (ret == 0) { /* no config file given */
1338 /*
1339 * Parse the command line options again, but this time check
1340 * that all required options are given.
1341 */
1342 params = (struct cmdline_parser_params) {
1343 .override = 1,
1344 .initialize = 1,
1345 .check_required = 1,
1346 .check_ambiguity = 1,
1347 .print_errors = 1
1348 };
1349 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1350 }
1351 if (conf.daemon_given)
1352 daemon_init();
1353 dump_dss_config("dss configuration");
1354 ret = change_to_dest_dir();
1355 if (ret < 0)
1356 goto out;
1357 ret = setup_signal_handling();
1358 if (ret < 0)
1359 goto out;
1360 ret = call_command_handler();
1361 out:
1362 if (ret < 0)
1363 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1364 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1365 }