Reuse old rsync argv if rsync has to be restarted.
[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,
254 conf.pre_remove_hook_arg, fds);
255 free(cmd);
256 if (ret < 0)
257 return ret;
258 snapshot_removal_status = HS_PRE_RUNNING;
259 return ret;
260 }
261
262 static int exec_rm(void)
263 {
264 struct snapshot *s = snapshot_currently_being_removed;
265 int fds[3] = {0, 0, 0};
266 char *new_name = being_deleted_name(s);
267 char *argv[] = {"rm", "-rf", new_name, NULL};
268 int ret;
269
270 assert(snapshot_removal_status == HS_PRE_SUCCESS);
271 assert(remove_pid == 0);
272
273 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
274 ret = dss_rename(s->name, new_name);
275 if (ret < 0)
276 goto out;
277 ret = dss_exec(&remove_pid, argv[0], argv, fds);
278 if (ret < 0)
279 goto out;
280 snapshot_removal_status = HS_RUNNING;
281 out:
282 free(new_name);
283 return ret;
284 }
285
286 static int snapshot_is_being_created(struct snapshot *s)
287 {
288 return s->creation_time == current_snapshot_creation_time;
289 }
290
291 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
292 {
293 struct snapshot *s;
294 int i;
295
296 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
297 FOR_EACH_SNAPSHOT(s, i, sl) {
298 if (snapshot_is_being_created(s))
299 continue;
300 /*
301 * We know that no rm is currently running, so if s is marked
302 * as being deleted, a previously started rm must have failed.
303 */
304 if (s->flags & SS_BEING_DELETED)
305 return s;
306
307 if (s->flags & SS_COMPLETE) /* good snapshot */
308 continue;
309 /*
310 * This snapshot is incomplete and it is not the snapshot
311 * currently being created. However, we must not remove it if
312 * rsync is about to be restarted. As only the newest snapshot
313 * can be restarted, this snapshot is orphaned if it is not the
314 * newest snapshot or if we are not about to restart rsync.
315 */
316 if (get_newest_snapshot(sl) != s)
317 return s;
318 if (snapshot_creation_status != HS_NEEDS_RESTART)
319 return s;
320 }
321 /* no orphaned snapshots */
322 return NULL;
323 }
324
325 static int is_reference_snapshot(struct snapshot *s)
326 {
327 if (!name_of_reference_snapshot)
328 return 0;
329 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
330 }
331
332 /*
333 * return: 0: no redundant snapshots, 1: rm process started, negative: error
334 */
335 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
336 {
337 int i, interval;
338 struct snapshot *s;
339 unsigned missing = 0;
340
341 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
342 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
343 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
344 unsigned num = sl->interval_count[interval];
345 struct snapshot *victim = NULL, *prev = NULL;
346 int64_t score = LONG_MAX;
347
348 if (keep >= num)
349 missing += keep - num;
350 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
351 // interval, keep, num, missing);
352 if (keep + missing >= num)
353 continue;
354 /* redundant snapshot in this interval, pick snapshot with lowest score */
355 FOR_EACH_SNAPSHOT(s, i, sl) {
356 int64_t this_score;
357
358 if (snapshot_is_being_created(s))
359 continue;
360 if (is_reference_snapshot(s))
361 continue;
362 //DSS_DEBUG_LOG("checking %s\n", s->name);
363 if (s->interval > interval) {
364 prev = s;
365 continue;
366 }
367 if (s->interval < interval)
368 break;
369 if (!victim) {
370 victim = s;
371 prev = s;
372 continue;
373 }
374 assert(prev);
375 /* check if s is a better victim */
376 this_score = s->creation_time - prev->creation_time;
377 assert(this_score >= 0);
378 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
379 if (this_score < score) {
380 score = this_score;
381 victim = s;
382 }
383 prev = s;
384 }
385 assert(victim);
386 return victim;
387 }
388 return NULL;
389 }
390
391 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
392 {
393 int i;
394 struct snapshot *s;
395
396 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
397 conf.num_intervals_arg);
398 FOR_EACH_SNAPSHOT(s, i, sl) {
399 if (snapshot_is_being_created(s))
400 continue;
401 if (is_reference_snapshot(s))
402 continue;
403 if (s->interval < conf.num_intervals_arg)
404 continue;
405 return s;
406 }
407 return NULL;
408 }
409
410 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
411 {
412 int i;
413 struct snapshot *s;
414 FOR_EACH_SNAPSHOT(s, i, sl) {
415 if (snapshot_is_being_created(s))
416 continue;
417 if (is_reference_snapshot(s))
418 continue;
419 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
420 return s;
421 }
422 return NULL;
423 }
424
425 static int rename_incomplete_snapshot(int64_t start)
426 {
427 char *old_name;
428 int ret;
429
430 free(path_to_last_complete_snapshot);
431 ret = complete_name(start, get_current_time(),
432 &path_to_last_complete_snapshot);
433 if (ret < 0)
434 return ret;
435 old_name = incomplete_name(start);
436 ret = dss_rename(old_name, path_to_last_complete_snapshot);
437 if (ret >= 0)
438 DSS_NOTICE_LOG("%s -> %s\n", old_name,
439 path_to_last_complete_snapshot);
440 free(old_name);
441 return ret;
442 }
443
444 static int try_to_free_disk_space(void)
445 {
446 int ret;
447 struct snapshot_list sl;
448 struct snapshot *victim;
449 struct timeval now;
450 const char *why;
451 int low_disk_space;
452
453 ret = disk_space_low();
454 if (ret < 0)
455 return ret;
456 low_disk_space = ret;
457 gettimeofday(&now, NULL);
458 if (tv_diff(&next_removal_check, &now, NULL) > 0)
459 return 0;
460 if (!low_disk_space) {
461 if (conf.keep_redundant_given)
462 return 0;
463 if (snapshot_creation_status != HS_READY)
464 return 0;
465 if (next_snapshot_is_due())
466 return 0;
467 }
468 dss_get_snapshot_list(&sl);
469 ret = 0;
470 if (!low_disk_space && sl.num_snapshots <= 1)
471 goto out;
472 why = "outdated";
473 victim = find_outdated_snapshot(&sl);
474 if (victim)
475 goto remove;
476 why = "redundant";
477 victim = find_redundant_snapshot(&sl);
478 if (victim)
479 goto remove;
480 /* try harder only if disk space is low */
481 if (!low_disk_space)
482 goto out;
483 why = "orphaned";
484 victim = find_orphaned_snapshot(&sl);
485 if (victim)
486 goto remove;
487 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
488 victim = find_oldest_removable_snapshot(&sl);
489 if (victim)
490 goto remove;
491 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
492 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
493 goto out;
494 remove:
495 ret = pre_remove_hook(victim, why);
496 out:
497 free_snapshot_list(&sl);
498 return ret;
499 }
500
501 static int post_create_hook(void)
502 {
503 int ret, fds[3] = {0, 0, 0};
504 char *cmd;
505
506 if (!conf.post_create_hook_given) {
507 create_pid = 0;
508 snapshot_creation_status = HS_READY;
509 return 0;
510 }
511 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
512 conf.dest_dir_arg, path_to_last_complete_snapshot);
513 DSS_NOTICE_LOG("executing %s\n", cmd);
514 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
515 free(cmd);
516 if (ret < 0)
517 return ret;
518 snapshot_creation_status = HS_POST_RUNNING;
519 return ret;
520 }
521
522 static int post_remove_hook(void)
523 {
524 int ret, fds[3] = {0, 0, 0};
525 char *cmd;
526 struct snapshot *s = snapshot_currently_being_removed;
527
528 assert(s);
529
530 if (!conf.post_remove_hook_given) {
531 snapshot_removal_status = HS_READY;
532 return 0;
533 }
534 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
535 conf.dest_dir_arg, s->name);
536 DSS_NOTICE_LOG("executing %s\n", cmd);
537 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
538 free(cmd);
539 if (ret < 0)
540 return ret;
541 snapshot_removal_status = HS_POST_RUNNING;
542 return ret;
543 }
544
545 static void kill_process(pid_t pid)
546 {
547 if (!pid)
548 return;
549 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
550 kill(pid, SIGTERM);
551 }
552
553 static void stop_create_process(void)
554 {
555 if (!create_pid || create_process_stopped)
556 return;
557 kill(SIGSTOP, create_pid);
558 create_process_stopped = 1;
559 }
560
561 static void restart_create_process(void)
562 {
563 if (!create_pid || !create_process_stopped)
564 return;
565 kill (SIGCONT, create_pid);
566 create_process_stopped = 0;
567 }
568
569 /**
570 * Print a log message about the exit status of a child.
571 */
572 static void log_termination_msg(pid_t pid, int status)
573 {
574 if (WIFEXITED(status))
575 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
576 WEXITSTATUS(status));
577 else if (WIFSIGNALED(status))
578 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
579 WTERMSIG(status));
580 else
581 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
582 }
583
584 static int wait_for_process(pid_t pid, int *status)
585 {
586 int ret;
587
588 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
589 for (;;) {
590 fd_set rfds;
591
592 FD_ZERO(&rfds);
593 FD_SET(signal_pipe, &rfds);
594 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
595 if (ret < 0)
596 break;
597 ret = next_signal();
598 if (!ret)
599 continue;
600 if (ret == SIGCHLD) {
601 ret = waitpid(pid, status, 0);
602 if (ret >= 0)
603 break;
604 if (errno != EINTR) { /* error */
605 ret = -ERRNO_TO_DSS_ERROR(errno);
606 break;
607 }
608 }
609 /* SIGINT or SIGTERM */
610 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
611 kill(pid, SIGTERM);
612 }
613 if (ret < 0)
614 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
615 else
616 log_termination_msg(pid, *status);
617 return ret;
618 }
619
620 static void handle_pre_remove_exit(int status)
621 {
622 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
623 snapshot_removal_status = HS_READY;
624 gettimeofday(&next_removal_check, NULL);
625 next_removal_check.tv_sec += 60;
626 return;
627 }
628 snapshot_removal_status = HS_PRE_SUCCESS;
629 }
630
631 static int handle_rm_exit(int status)
632 {
633 if (!WIFEXITED(status)) {
634 snapshot_removal_status = HS_READY;
635 return -E_INVOLUNTARY_EXIT;
636 }
637 if (WEXITSTATUS(status)) {
638 snapshot_removal_status = HS_READY;
639 return -E_BAD_EXIT_CODE;
640 }
641 if (conf.post_remove_hook_given)
642 snapshot_removal_status = HS_SUCCESS;
643 else
644 snapshot_removal_status = HS_READY;
645 return 1;
646 }
647
648 static void handle_post_remove_exit(void)
649 {
650 snapshot_removal_status = HS_READY;
651 }
652
653 static int handle_remove_exit(int status)
654 {
655 int ret;
656 struct snapshot *s = snapshot_currently_being_removed;
657
658 assert(s);
659 switch (snapshot_removal_status) {
660 case HS_PRE_RUNNING:
661 handle_pre_remove_exit(status);
662 ret = 1;
663 break;
664 case HS_RUNNING:
665 ret = handle_rm_exit(status);
666 break;
667 case HS_POST_RUNNING:
668 handle_post_remove_exit();
669 ret = 1;
670 break;
671 default:
672 ret = -E_BUG;
673 }
674 if (snapshot_removal_status == HS_READY) {
675 free(s->name);
676 free(s);
677 snapshot_currently_being_removed = NULL;
678 }
679 remove_pid = 0;
680 return ret;
681 }
682
683 static int wait_for_remove_process(void)
684 {
685 int status, ret;
686
687 assert(remove_pid);
688 assert(
689 snapshot_removal_status == HS_PRE_RUNNING ||
690 snapshot_removal_status == HS_RUNNING ||
691 snapshot_removal_status == HS_POST_RUNNING
692 );
693 ret = wait_for_process(remove_pid, &status);
694 if (ret < 0)
695 return ret;
696 return handle_remove_exit(status);
697 }
698
699 static int handle_rsync_exit(int status)
700 {
701 int es, ret;
702
703 if (!WIFEXITED(status)) {
704 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
705 ret = -E_INVOLUNTARY_EXIT;
706 snapshot_creation_status = HS_READY;
707 goto out;
708 }
709 es = WEXITSTATUS(status);
710 /*
711 * Restart rsync on non-fatal errors:
712 * 12: Error in rsync protocol data stream
713 * 13: Errors with program diagnostics
714 */
715 if (es == 12 || es == 13) {
716 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
717 (int)create_pid, es);
718 snapshot_creation_status = HS_NEEDS_RESTART;
719 next_snapshot_time = get_current_time() + 60;
720 ret = 1;
721 goto out;
722 }
723 if (es != 0 && es != 23 && es != 24) {
724 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
725 ret = -E_BAD_EXIT_CODE;
726 snapshot_creation_status = HS_READY;
727 goto out;
728 }
729 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
730 if (ret < 0)
731 goto out;
732 snapshot_creation_status = HS_SUCCESS;
733 free(name_of_reference_snapshot);
734 name_of_reference_snapshot = NULL;
735 out:
736 create_process_stopped = 0;
737 return ret;
738 }
739
740 static int handle_pre_create_hook_exit(int status)
741 {
742 int es, ret;
743 static int warn_count;
744
745 if (!WIFEXITED(status)) {
746 snapshot_creation_status = HS_READY;
747 ret = -E_INVOLUNTARY_EXIT;
748 goto out;
749 }
750 es = WEXITSTATUS(status);
751 if (es) {
752 if (!warn_count--) {
753 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
754 conf.pre_create_hook_arg, es);
755 DSS_NOTICE_LOG("deferring snapshot creation...\n");
756 warn_count = 60; /* warn only once per hour */
757 }
758 next_snapshot_time = get_current_time() + 60;
759 snapshot_creation_status = HS_READY;
760 ret = 0;
761 goto out;
762 }
763 warn_count = 0;
764 snapshot_creation_status = HS_PRE_SUCCESS;
765 ret = 1;
766 out:
767 return ret;
768 }
769
770 static int handle_sigchld(void)
771 {
772 pid_t pid;
773 int status, ret = reap_child(&pid, &status);
774
775 if (ret <= 0)
776 return ret;
777
778 if (pid == create_pid) {
779 switch (snapshot_creation_status) {
780 case HS_PRE_RUNNING:
781 return handle_pre_create_hook_exit(status);
782 case HS_RUNNING:
783 return handle_rsync_exit(status);
784 case HS_POST_RUNNING:
785 snapshot_creation_status = HS_READY;
786 return 1;
787 default:
788 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
789 snapshot_creation_status);
790 return -E_BUG;
791 }
792 create_pid = 0;
793 }
794 if (pid == remove_pid) {
795 ret = handle_remove_exit(status);
796 if (ret < 0)
797 return ret;
798 return ret;
799 }
800 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
801 return -E_BUG;
802 }
803
804 static int check_config(void)
805 {
806 if (conf.unit_interval_arg <= 0) {
807 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
808 return -E_INVALID_NUMBER;
809 }
810 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
811 if (conf.num_intervals_arg <= 0) {
812 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
813 return -E_INVALID_NUMBER;
814 }
815 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
816 return 1;
817 }
818
819 /*
820 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
821 * file was read successfully.
822 */
823 static int parse_config_file(int override)
824 {
825 int ret, config_file_exists;
826 char *config_file;
827 struct stat statbuf;
828 char *old_logfile_arg = NULL;
829 int old_daemon_given = 0;
830
831 if (conf.config_file_given)
832 config_file = dss_strdup(conf.config_file_arg);
833 else {
834 char *home = get_homedir();
835 config_file = make_message("%s/.dssrc", home);
836 free(home);
837 }
838 if (override) { /* SIGHUP */
839 if (conf.logfile_given)
840 old_logfile_arg = dss_strdup(conf.logfile_arg);
841 old_daemon_given = conf.daemon_given;
842 }
843
844 config_file_exists = !stat(config_file, &statbuf);
845 if (!config_file_exists && conf.config_file_given) {
846 ret = -ERRNO_TO_DSS_ERROR(errno);
847 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
848 goto out;
849 }
850 if (config_file_exists) {
851 struct cmdline_parser_params params = {
852 .override = override,
853 .initialize = 0,
854 .check_required = 1,
855 .check_ambiguity = 0,
856 .print_errors = 1
857 };
858 if (override) { /* invalidate all rsync options */
859 int i;
860
861 for (i = 0; i < conf.rsync_option_given; i++) {
862 free(conf.rsync_option_arg[i]);
863 conf.rsync_option_arg[i] = NULL;
864 }
865 conf.rsync_option_given = 0;
866 }
867 cmdline_parser_config_file(config_file, &conf, &params);
868 }
869 ret = check_config();
870 if (ret < 0)
871 goto out;
872 if (override) {
873 /* don't change daemon mode on SIGHUP */
874 conf.daemon_given = old_daemon_given;
875 close_log(logfile);
876 logfile = NULL;
877 if (conf.logfile_given)
878 free(old_logfile_arg);
879 else if (conf.daemon_given) { /* re-use old logfile */
880 conf.logfile_arg = old_logfile_arg;
881 conf.logfile_given = 1;
882 }
883 }
884 if (conf.logfile_given) {
885 logfile = open_log(conf.logfile_arg);
886 log_welcome(conf.loglevel_arg);
887 }
888 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
889 ret = config_file_exists;
890 out:
891 free(config_file);
892 if (ret < 0)
893 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
894 return ret;
895 }
896
897 static int change_to_dest_dir(void)
898 {
899 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
900 return dss_chdir(conf.dest_dir_arg);
901 }
902
903 static void dump_dss_config(const char *msg)
904 {
905 if (conf.loglevel_arg > INFO)
906 return;
907 DSS_INFO_LOG("%s\n", msg);
908 cmdline_parser_dump(logfile? logfile : stderr, &conf);
909 }
910
911 static int handle_sighup(void)
912 {
913 int ret;
914
915 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
916 dump_dss_config("current config");
917 ret = parse_config_file(1);
918 if (ret < 0)
919 return ret;
920 dump_dss_config("new config");
921 invalidate_next_snapshot_time();
922 return change_to_dest_dir();
923 }
924
925 static int handle_signal(void)
926 {
927 int sig, ret = next_signal();
928
929 if (ret <= 0)
930 goto out;
931 sig = ret;
932 switch (sig) {
933 case SIGINT:
934 case SIGTERM:
935 restart_create_process();
936 kill_process(create_pid);
937 kill_process(remove_pid);
938 ret = -E_SIGNAL;
939 break;
940 case SIGHUP:
941 ret = handle_sighup();
942 break;
943 case SIGCHLD:
944 ret = handle_sigchld();
945 break;
946 }
947 out:
948 if (ret < 0)
949 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
950 return ret;
951 }
952
953 /*
954 * We can not use rsync locally if the local user is different from the remote
955 * user or if the src dir is not on the local host (or both).
956 */
957 static int use_rsync_locally(char *logname)
958 {
959 char *h = conf.remote_host_arg;
960
961 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
962 return 0;
963 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
964 return 0;
965 return 1;
966 }
967
968 static int rename_resume_snap(int64_t creation_time)
969 {
970 struct snapshot_list sl = {.num_snapshots = 0};
971 struct snapshot *s;
972 char *new_name = incomplete_name(creation_time);
973 int ret;
974
975 ret = 0;
976 if (conf.no_resume_given)
977 goto out;
978 dss_get_snapshot_list(&sl);
979 s = get_newest_snapshot(&sl);
980 if (!s)
981 goto out;
982 if ((s->flags & SS_COMPLETE) != 0) /* complete */
983 goto out;
984 DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
985 ret = dss_rename(s->name, new_name);
986 out:
987 if (ret >= 0)
988 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
989 free(new_name);
990 free_snapshot_list(&sl);
991 return ret;
992 }
993
994 static void create_rsync_argv(char ***argv, int64_t *num)
995 {
996 char *logname;
997 int i = 0, j;
998 struct snapshot_list sl;
999
1000 dss_get_snapshot_list(&sl);
1001 assert(!name_of_reference_snapshot);
1002 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1003 free_snapshot_list(&sl);
1004
1005 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1006 (*argv)[i++] = dss_strdup("rsync");
1007 (*argv)[i++] = dss_strdup("-aq");
1008 (*argv)[i++] = dss_strdup("--delete");
1009 for (j = 0; j < conf.rsync_option_given; j++)
1010 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1011 if (name_of_reference_snapshot) {
1012 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1013 (*argv)[i++] = make_message("--link-dest=../%s",
1014 name_of_reference_snapshot);
1015 } else
1016 DSS_INFO_LOG("no suitable reference snapshot found\n");
1017 logname = dss_logname();
1018 if (use_rsync_locally(logname))
1019 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1020 else
1021 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1022 conf.remote_user_arg : logname,
1023 conf.remote_host_arg, conf.source_dir_arg);
1024 free(logname);
1025 *num = get_current_time();
1026 (*argv)[i++] = incomplete_name(*num);
1027 (*argv)[i++] = NULL;
1028 for (j = 0; j < i; j++)
1029 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1030 }
1031
1032 static void free_rsync_argv(char **argv)
1033 {
1034 int i;
1035
1036 if (!argv)
1037 return;
1038 for (i = 0; argv[i]; i++)
1039 free(argv[i]);
1040 free(argv);
1041 }
1042
1043 static int create_snapshot(char **argv)
1044 {
1045 int ret, fds[3] = {0, 0, 0};
1046
1047 ret = rename_resume_snap(current_snapshot_creation_time);
1048 if (ret < 0)
1049 return ret;
1050 ret = dss_exec(&create_pid, argv[0], argv, fds);
1051 if (ret < 0)
1052 return ret;
1053 snapshot_creation_status = HS_RUNNING;
1054 return ret;
1055 }
1056
1057 static int select_loop(void)
1058 {
1059 int ret;
1060 /* check every 60 seconds for free disk space */
1061 struct timeval tv;
1062 char **rsync_argv = NULL;
1063
1064 for (;;) {
1065 fd_set rfds;
1066 struct timeval *tvp;
1067
1068 if (remove_pid)
1069 tvp = NULL; /* sleep until rm hook/process dies */
1070 else { /* sleep one minute */
1071 tv.tv_sec = 60;
1072 tv.tv_usec = 0;
1073 tvp = &tv;
1074 }
1075 FD_ZERO(&rfds);
1076 FD_SET(signal_pipe, &rfds);
1077 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1078 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1079 if (ret < 0)
1080 goto out;
1081 if (FD_ISSET(signal_pipe, &rfds)) {
1082 ret = handle_signal();
1083 if (ret < 0)
1084 goto out;
1085 }
1086 if (remove_pid)
1087 continue;
1088 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1089 ret = exec_rm();
1090 if (ret < 0)
1091 goto out;
1092 continue;
1093 }
1094 if (snapshot_removal_status == HS_SUCCESS) {
1095 ret = post_remove_hook();
1096 if (ret < 0)
1097 goto out;
1098 continue;
1099 }
1100 ret = try_to_free_disk_space();
1101 if (ret < 0)
1102 goto out;
1103 if (snapshot_removal_status != HS_READY) {
1104 stop_create_process();
1105 continue;
1106 }
1107 restart_create_process();
1108 switch (snapshot_creation_status) {
1109 case HS_READY:
1110 if (!next_snapshot_is_due())
1111 continue;
1112 ret = pre_create_hook();
1113 if (ret < 0)
1114 goto out;
1115 continue;
1116 case HS_PRE_RUNNING:
1117 case HS_RUNNING:
1118 case HS_POST_RUNNING:
1119 continue;
1120 case HS_PRE_SUCCESS:
1121 if (!name_of_reference_snapshot) {
1122 free_rsync_argv(rsync_argv);
1123 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1124 }
1125 /* fall through */
1126 case HS_NEEDS_RESTART:
1127 if (!next_snapshot_is_due())
1128 continue;
1129 ret = create_snapshot(rsync_argv);
1130 if (ret < 0)
1131 goto out;
1132 continue;
1133 case HS_SUCCESS:
1134 ret = post_create_hook();
1135 if (ret < 0)
1136 goto out;
1137 continue;
1138 }
1139 }
1140 out:
1141 return ret;
1142 }
1143
1144 static void exit_hook(int exit_code)
1145 {
1146 int fds[3] = {0, 0, 0};
1147 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1148 pid_t pid;
1149
1150 if (!conf.exit_hook_given)
1151 return;
1152 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1153 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1154 }
1155
1156 static int com_run(void)
1157 {
1158 int ret;
1159
1160 if (conf.dry_run_given) {
1161 DSS_ERROR_LOG("dry_run not supported by this command\n");
1162 return -E_SYNTAX;
1163 }
1164 ret = install_sighandler(SIGHUP);
1165 if (ret < 0)
1166 return ret;
1167 ret = select_loop();
1168 if (ret >= 0) /* impossible */
1169 ret = -E_BUG;
1170 exit_hook(ret);
1171 return ret;
1172 }
1173
1174 static int com_prune(void)
1175 {
1176 int ret;
1177 struct snapshot_list sl;
1178 struct snapshot *victim;
1179 struct disk_space ds;
1180 const char *why;
1181
1182 ret = get_disk_space(".", &ds);
1183 if (ret < 0)
1184 return ret;
1185 log_disk_space(&ds);
1186 dss_get_snapshot_list(&sl);
1187 why = "outdated";
1188 victim = find_outdated_snapshot(&sl);
1189 if (victim)
1190 goto rm;
1191 why = "redundant";
1192 victim = find_redundant_snapshot(&sl);
1193 if (victim)
1194 goto rm;
1195 ret = 0;
1196 goto out;
1197 rm:
1198 if (conf.dry_run_given) {
1199 dss_msg("%s snapshot %s (interval = %i)\n",
1200 why, victim->name, victim->interval);
1201 ret = 0;
1202 goto out;
1203 }
1204 ret = pre_remove_hook(victim, why);
1205 if (ret < 0)
1206 goto out;
1207 if (snapshot_removal_status == HS_PRE_RUNNING) {
1208 ret = wait_for_remove_process();
1209 if (ret < 0)
1210 goto out;
1211 if (snapshot_removal_status != HS_PRE_SUCCESS)
1212 goto out;
1213 }
1214 ret = exec_rm();
1215 if (ret < 0)
1216 goto out;
1217 ret = wait_for_remove_process();
1218 if (ret < 0)
1219 goto out;
1220 if (snapshot_removal_status != HS_SUCCESS)
1221 goto out;
1222 ret = post_remove_hook();
1223 if (ret < 0)
1224 goto out;
1225 if (snapshot_removal_status != HS_POST_RUNNING)
1226 goto out;
1227 ret = wait_for_remove_process();
1228 if (ret < 0)
1229 goto out;
1230 ret = 1;
1231 out:
1232 free_snapshot_list(&sl);
1233 return ret;
1234 }
1235
1236 static int com_create(void)
1237 {
1238 int ret, status;
1239 char **rsync_argv;
1240
1241 if (conf.dry_run_given) {
1242 int i;
1243 char *msg = NULL;
1244 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1245 for (i = 0; rsync_argv[i]; i++) {
1246 char *tmp = msg;
1247 msg = make_message("%s%s%s", tmp? tmp : "",
1248 tmp? " " : "", rsync_argv[i]);
1249 free(tmp);
1250 }
1251 free_rsync_argv(rsync_argv);
1252 dss_msg("%s\n", msg);
1253 free(msg);
1254 return 1;
1255 }
1256 ret = pre_create_hook();
1257 if (ret < 0)
1258 return ret;
1259 if (create_pid) {
1260 ret = wait_for_process(create_pid, &status);
1261 if (ret < 0)
1262 return ret;
1263 ret = handle_pre_create_hook_exit(status);
1264 if (ret <= 0) /* error, or pre-create failed */
1265 return ret;
1266 }
1267 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1268 ret = create_snapshot(rsync_argv);
1269 if (ret < 0)
1270 goto out;
1271 ret = wait_for_process(create_pid, &status);
1272 if (ret < 0)
1273 goto out;
1274 ret = handle_rsync_exit(status);
1275 if (ret < 0)
1276 goto out;
1277 post_create_hook();
1278 if (create_pid)
1279 ret = wait_for_process(create_pid, &status);
1280 out:
1281 free_rsync_argv(rsync_argv);
1282 return ret;
1283 }
1284
1285 static int com_ls(void)
1286 {
1287 int i;
1288 struct snapshot_list sl;
1289 struct snapshot *s;
1290
1291 dss_get_snapshot_list(&sl);
1292 FOR_EACH_SNAPSHOT(s, i, &sl) {
1293 int64_t d = 0;
1294 if (s->flags & SS_COMPLETE)
1295 d = (s->completion_time - s->creation_time) / 60;
1296 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1297 };
1298 free_snapshot_list(&sl);
1299 return 1;
1300 }
1301
1302 static int setup_signal_handling(void)
1303 {
1304 int ret;
1305
1306 DSS_INFO_LOG("setting up signal handlers\n");
1307 signal_pipe = signal_init(); /* always successful */
1308 ret = install_sighandler(SIGINT);
1309 if (ret < 0)
1310 return ret;
1311 ret = install_sighandler(SIGTERM);
1312 if (ret < 0)
1313 return ret;
1314 return install_sighandler(SIGCHLD);
1315 }
1316
1317 /**
1318 * The main function of dss.
1319 *
1320 * \param argc Usual argument count.
1321 * \param argv Usual argument vector.
1322 */
1323 int main(int argc, char **argv)
1324 {
1325 int ret;
1326 struct cmdline_parser_params params = {
1327 .override = 0,
1328 .initialize = 1,
1329 .check_required = 0,
1330 .check_ambiguity = 0,
1331 .print_errors = 1
1332 };
1333
1334 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1335 ret = parse_config_file(0);
1336 if (ret < 0)
1337 goto out;
1338 if (ret == 0) { /* no config file given */
1339 /*
1340 * Parse the command line options again, but this time check
1341 * that all required options are given.
1342 */
1343 params = (struct cmdline_parser_params) {
1344 .override = 1,
1345 .initialize = 1,
1346 .check_required = 1,
1347 .check_ambiguity = 1,
1348 .print_errors = 1
1349 };
1350 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1351 }
1352 if (conf.daemon_given)
1353 daemon_init();
1354 dump_dss_config("dss configuration");
1355 ret = change_to_dest_dir();
1356 if (ret < 0)
1357 goto out;
1358 ret = setup_signal_handling();
1359 if (ret < 0)
1360 goto out;
1361 ret = call_command_handler();
1362 out:
1363 if (ret < 0)
1364 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1365 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1366 }