Remove orphaned snapshots first if disk space is low.
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008 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 struct timeval 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 /** \sa \ref snap.h for details. */
60 enum hook_status snapshot_creation_status;
61 /** \sa \ref snap.h for details. */
62 enum hook_status snapshot_removal_status;
63
64
65 DEFINE_DSS_ERRLIST;
66
67
68 /* a litte cpp magic helps to DRY */
69 #define COMMANDS \
70 COMMAND(ls) \
71 COMMAND(create) \
72 COMMAND(prune) \
73 COMMAND(run)
74 #define COMMAND(x) static int com_ ##x(void);
75 COMMANDS
76 #undef COMMAND
77 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
78 static int call_command_handler(void)
79 {
80 COMMANDS
81 DSS_EMERG_LOG("BUG: did not find command handler\n");
82 return -E_BUG;
83 }
84 #undef COMMAND
85 #undef COMMANDS
86
87 /**
88 * The log function of dss.
89 *
90 * \param ll Loglevel.
91 * \param fml Usual format string.
92 *
93 * All DSS_XXX_LOG() macros use this function.
94 */
95 __printf_2_3 void dss_log(int ll, const char* fmt,...)
96 {
97 va_list argp;
98 FILE *outfd;
99 struct tm *tm;
100 time_t t1;
101 char str[255] = "";
102
103 if (ll < conf.loglevel_arg)
104 return;
105 outfd = logfile? logfile : stderr;
106 time(&t1);
107 tm = localtime(&t1);
108 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
109 fprintf(outfd, "%s ", str);
110 if (conf.loglevel_arg <= INFO)
111 fprintf(outfd, "%i: ", ll);
112 va_start(argp, fmt);
113 vfprintf(outfd, fmt, argp);
114 va_end(argp);
115 }
116
117 /**
118 * Print a message either to stdout or to the log file.
119 */
120 static __printf_1_2 void dss_msg(const char* fmt,...)
121 {
122 FILE *outfd = conf.daemon_given? logfile : stdout;
123 va_list argp;
124 va_start(argp, fmt);
125 vfprintf(outfd, fmt, argp);
126 va_end(argp);
127 }
128
129 static int disk_space_low(void)
130 {
131 struct disk_space ds;
132 int ret = get_disk_space(".", &ds);
133
134 if (ret < 0)
135 return ret;
136 if (conf.min_free_mb_arg)
137 if (ds.free_mb < conf.min_free_mb_arg)
138 return 1;
139 if (conf.min_free_percent_arg)
140 if (ds.percent_free < conf.min_free_percent_arg)
141 return 1;
142 if (conf.min_free_percent_inodes_arg)
143 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
144 return 1;
145 return 0;
146 }
147
148 static void dss_get_snapshot_list(struct snapshot_list *sl)
149 {
150 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
151 }
152
153 static int next_snapshot_is_due(void)
154 {
155 struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
156 tmp, diff;
157 int64_t x = 0;
158 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
159 num_complete_snapshots = 0;
160 int i, ret;
161 struct snapshot *s = NULL;
162 struct snapshot_list sl;
163
164 gettimeofday(&now, NULL);
165 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
166 return 0;
167 assert(snapshot_creation_status == HS_READY);
168 current_snapshot_creation_time = 0;
169 dss_get_snapshot_list(&sl);
170 FOR_EACH_SNAPSHOT(s, i, &sl) {
171 if (!(s->flags & SS_COMPLETE))
172 continue;
173 num_complete_snapshots++;
174 x += s->completion_time - s->creation_time;
175 }
176 assert(x >= 0);
177 if (num_complete_snapshots)
178 x /= num_complete_snapshots; /* avg time to create one snapshot */
179 x *= wanted; /* time to create all snapshots in interval 0 */
180 tmp.tv_sec = x;
181 tmp.tv_usec = 0;
182 ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
183 if (ret < 0 || !s) { /* unit_interval < tmp or no snapshot */
184 ret = 1;
185 goto out;
186 }
187
188 tv_divide(wanted, &diff, &tmp); /* sleep time between two snapshots */
189 diff.tv_sec = s->completion_time; /* completion time of the latest snapshot */
190 diff.tv_usec = 0;
191 tv_add(&diff, &tmp, &next_snapshot_time);
192 ret = (tv_diff(&now, &next_snapshot_time, &diff) < 0)? 0 : 1;
193 out:
194 free_snapshot_list(&sl);
195 if (ret == 0)
196 DSS_DEBUG_LOG("next snapshot due in %lu seconds\n",
197 tv2ms(&diff) / 1000);
198 else
199 DSS_DEBUG_LOG("next snapshot: now\n");
200 return ret;
201 }
202
203 static int pre_create_hook(void)
204 {
205 int ret, fds[3] = {0, 0, 0};
206
207 assert(snapshot_creation_status == HS_READY);
208 if (!conf.pre_create_hook_given) {
209 snapshot_creation_status = HS_PRE_SUCCESS;
210 return 0;
211 }
212 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
213 ret = dss_exec_cmdline_pid(&create_pid,
214 conf.pre_create_hook_arg, fds);
215 if (ret < 0)
216 return ret;
217 snapshot_creation_status = HS_PRE_RUNNING;
218 return ret;
219 }
220
221 static int pre_remove_hook(struct snapshot *s, char *why)
222 {
223 int ret, fds[3] = {0, 0, 0};
224 char *cmd;
225
226 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
227 assert(snapshot_removal_status == HS_READY);
228 assert(remove_pid == 0);
229 assert(!snapshot_currently_being_removed);
230
231 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
232 *snapshot_currently_being_removed = *s;
233 snapshot_currently_being_removed->name = dss_strdup(s->name);
234
235 if (!conf.pre_remove_hook_given) {
236 snapshot_removal_status = HS_PRE_SUCCESS;
237 return 0;
238 }
239 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
240 conf.dest_dir_arg, s->name);
241 DSS_DEBUG_LOG("executing %s\n", cmd);
242 ret = dss_exec_cmdline_pid(&remove_pid,
243 conf.pre_remove_hook_arg, fds);
244 free(cmd);
245 if (ret < 0)
246 return ret;
247 snapshot_removal_status = HS_PRE_RUNNING;
248 return ret;
249 }
250
251 static int exec_rm(void)
252 {
253 struct snapshot *s = snapshot_currently_being_removed;
254 int fds[3] = {0, 0, 0};
255 char *new_name = being_deleted_name(s);
256 char *argv[] = {"rm", "-rf", new_name, NULL};
257 int ret;
258
259 assert(snapshot_removal_status == HS_PRE_SUCCESS);
260 assert(remove_pid == 0);
261
262 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
263 ret = dss_rename(s->name, new_name);
264 if (ret < 0)
265 goto out;
266 ret = dss_exec(&remove_pid, argv[0], argv, fds);
267 if (ret < 0)
268 goto out;
269 snapshot_removal_status = HS_RUNNING;
270 out:
271 free(new_name);
272 return ret;
273 }
274
275 static int snapshot_is_being_created(struct snapshot *s)
276 {
277 return s->creation_time == current_snapshot_creation_time;
278 }
279
280 static int remove_orphaned_snapshot(struct snapshot_list *sl)
281 {
282 struct snapshot *s;
283 int i, ret;
284
285 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
286 FOR_EACH_SNAPSHOT(s, i, sl) {
287 if (snapshot_is_being_created(s))
288 continue;
289 /*
290 * We know that no rm is currently running, so if s is marked
291 * as being deleted, a previously started rm must have failed.
292 */
293 if (s->flags & SS_BEING_DELETED)
294 goto remove;
295
296 if (s->flags & SS_COMPLETE) /* good snapshot */
297 continue;
298 /*
299 * This snapshot is incomplete and it is not the snapshot
300 * currently being created. However, we must not remove it if
301 * rsync is about to be restarted. As only the newest snapshot
302 * can be restarted, this snapshot is orphaned if it is not the
303 * newest snapshot or if we are not about to restart rsync.
304 */
305 if (get_newest_snapshot(sl) != s)
306 goto remove;
307 if (snapshot_creation_status != HS_NEEDS_RESTART)
308 goto remove;
309 }
310 return 0; /* no orphaned snapshots */
311 remove:
312 ret = pre_remove_hook(s, "orphaned");
313 if (ret < 0)
314 return ret;
315 return 1;
316 }
317
318 /*
319 * return: 0: no redundant snapshots, 1: rm process started, negative: error
320 */
321 static int remove_redundant_snapshot(struct snapshot_list *sl)
322 {
323 int ret, i, interval;
324 struct snapshot *s;
325 unsigned missing = 0;
326
327 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
328 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
329 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
330 unsigned num = sl->interval_count[interval];
331 struct snapshot *victim = NULL, *prev = NULL;
332 int64_t score = LONG_MAX;
333
334 if (keep >= num)
335 missing += keep - num;
336 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
337 // interval, keep, num, missing);
338 if (keep + missing >= num)
339 continue;
340 /* redundant snapshot in this interval, pick snapshot with lowest score */
341 FOR_EACH_SNAPSHOT(s, i, sl) {
342 int64_t this_score;
343
344 if (snapshot_is_being_created(s))
345 continue;
346 //DSS_DEBUG_LOG("checking %s\n", s->name);
347 if (s->interval > interval) {
348 prev = s;
349 continue;
350 }
351 if (s->interval < interval)
352 break;
353 if (!victim) {
354 victim = s;
355 prev = s;
356 continue;
357 }
358 assert(prev);
359 /* check if s is a better victim */
360 this_score = s->creation_time - prev->creation_time;
361 assert(this_score >= 0);
362 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
363 if (this_score < score) {
364 score = this_score;
365 victim = s;
366 }
367 prev = s;
368 }
369 assert(victim);
370 if (conf.dry_run_given) {
371 dss_msg("%s would be removed (interval = %i)\n",
372 victim->name, victim->interval);
373 continue;
374 }
375 ret = pre_remove_hook(victim, "redundant");
376 return ret < 0? ret : 1;
377 }
378 return 0;
379 }
380
381 static int remove_outdated_snapshot(struct snapshot_list *sl)
382 {
383 int i, ret;
384 struct snapshot *s;
385
386 DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
387 conf.num_intervals_arg);
388 FOR_EACH_SNAPSHOT(s, i, sl) {
389 if (snapshot_is_being_created(s))
390 continue;
391 if (s->interval <= conf.num_intervals_arg)
392 continue;
393 if (conf.dry_run_given) {
394 dss_msg("%s would be removed (interval = %i)\n",
395 s->name, s->interval);
396 continue;
397 }
398 ret = pre_remove_hook(s, "outdated");
399 if (ret < 0)
400 return ret;
401 return 1;
402 }
403 return 0;
404 }
405
406 static int remove_oldest_snapshot(struct snapshot_list *sl)
407 {
408 int ret;
409 struct snapshot *s = get_oldest_snapshot(sl);
410
411 if (!s) /* no snapshot found */
412 return 0;
413 DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
414 if (snapshot_is_being_created(s))
415 return 0;
416 ret = pre_remove_hook(s, "oldest");
417 if (ret < 0)
418 return ret;
419 return 1;
420 }
421
422 static int rename_incomplete_snapshot(int64_t start)
423 {
424 char *old_name;
425 int ret;
426
427 free(path_to_last_complete_snapshot);
428 ret = complete_name(start, get_current_time(),
429 &path_to_last_complete_snapshot);
430 if (ret < 0)
431 return ret;
432 old_name = incomplete_name(start);
433 ret = dss_rename(old_name, path_to_last_complete_snapshot);
434 if (ret >= 0)
435 DSS_NOTICE_LOG("%s -> %s\n", old_name,
436 path_to_last_complete_snapshot);
437 free(old_name);
438 return ret;
439 }
440
441 static int try_to_free_disk_space(int low_disk_space)
442 {
443 int ret;
444 struct snapshot_list sl;
445 struct timeval now;
446
447 gettimeofday(&now, NULL);
448 if (tv_diff(&next_removal_check, &now, NULL) > 0)
449 return 0;
450 if (!low_disk_space && conf.keep_redundant_given)
451 return 0;
452 dss_get_snapshot_list(&sl);
453 ret = remove_outdated_snapshot(&sl);
454 if (ret) /* error, or we are removing something */
455 goto out;
456 /* no outdated snapshot */
457 ret = remove_redundant_snapshot(&sl);
458 if (ret)
459 goto out;
460 ret = 0;
461 if (!low_disk_space)
462 goto out;
463 ret = remove_orphaned_snapshot(&sl);
464 if (ret)
465 goto out;
466 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
467 ret = remove_oldest_snapshot(&sl);
468 if (ret)
469 goto out;
470 DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
471 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
472 out:
473 free_snapshot_list(&sl);
474 return ret;
475 }
476
477 static int post_create_hook(void)
478 {
479 int ret, fds[3] = {0, 0, 0};
480 char *cmd;
481
482 if (!conf.post_create_hook_given) {
483 snapshot_creation_status = HS_READY;
484 return 0;
485 }
486 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
487 conf.dest_dir_arg, path_to_last_complete_snapshot);
488 DSS_NOTICE_LOG("executing %s\n", cmd);
489 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
490 free(cmd);
491 if (ret < 0)
492 return ret;
493 snapshot_creation_status = HS_POST_RUNNING;
494 return ret;
495 }
496
497 static int post_remove_hook(void)
498 {
499 int ret, fds[3] = {0, 0, 0};
500 char *cmd;
501 struct snapshot *s = snapshot_currently_being_removed;
502
503 assert(s);
504
505 if (!conf.post_remove_hook_given) {
506 snapshot_removal_status = HS_READY;
507 return 0;
508 }
509 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
510 conf.dest_dir_arg, s->name);
511 DSS_NOTICE_LOG("executing %s\n", cmd);
512 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
513 free(cmd);
514 if (ret < 0)
515 return ret;
516 snapshot_removal_status = HS_POST_RUNNING;
517 return ret;
518 }
519
520 static void kill_process(pid_t pid)
521 {
522 if (!pid)
523 return;
524 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
525 kill(pid, SIGTERM);
526 }
527
528 static void stop_create_process(void)
529 {
530 if (!create_pid || create_process_stopped)
531 return;
532 kill(SIGSTOP, create_pid);
533 create_process_stopped = 1;
534 }
535
536 static void restart_create_process(void)
537 {
538 if (!create_pid || !create_process_stopped)
539 return;
540 kill (SIGCONT, create_pid);
541 create_process_stopped = 0;
542 }
543
544 /**
545 * Print a log message about the exit status of a child.
546 */
547 static void log_termination_msg(pid_t pid, int status)
548 {
549 if (WIFEXITED(status))
550 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
551 WEXITSTATUS(status));
552 else if (WIFSIGNALED(status))
553 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
554 WTERMSIG(status));
555 else
556 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
557 }
558
559 static int wait_for_process(pid_t pid, int *status)
560 {
561 int ret;
562
563 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
564 for (;;) {
565 fd_set rfds;
566
567 FD_ZERO(&rfds);
568 FD_SET(signal_pipe, &rfds);
569 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
570 if (ret < 0)
571 break;
572 ret = next_signal();
573 if (!ret)
574 continue;
575 if (ret == SIGCHLD) {
576 ret = waitpid(pid, status, 0);
577 if (ret >= 0)
578 break;
579 if (errno != EINTR) { /* error */
580 ret = -ERRNO_TO_DSS_ERROR(errno);
581 break;
582 }
583 }
584 /* SIGINT or SIGTERM */
585 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
586 kill(pid, SIGTERM);
587 }
588 if (ret < 0)
589 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
590 else
591 log_termination_msg(pid, *status);
592 return ret;
593 }
594
595 static void handle_pre_remove_exit(int status)
596 {
597 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
598 snapshot_removal_status = HS_READY;
599 gettimeofday(&next_removal_check, NULL);
600 next_removal_check.tv_sec += 60;
601 return;
602 }
603 snapshot_removal_status = HS_PRE_SUCCESS;
604 }
605
606 static int handle_rm_exit(int status)
607 {
608 if (!WIFEXITED(status)) {
609 snapshot_removal_status = HS_READY;
610 return -E_INVOLUNTARY_EXIT;
611 }
612 if (WEXITSTATUS(status)) {
613 snapshot_removal_status = HS_READY;
614 return -E_BAD_EXIT_CODE;
615 }
616 if (conf.post_remove_hook_given)
617 snapshot_removal_status = HS_SUCCESS;
618 else
619 snapshot_removal_status = HS_READY;
620 return 1;
621 }
622
623 static void handle_post_remove_exit(void)
624 {
625 snapshot_removal_status = HS_READY;
626 }
627
628 static int handle_remove_exit(int status)
629 {
630 int ret;
631 struct snapshot *s = snapshot_currently_being_removed;
632
633 assert(s);
634 switch (snapshot_removal_status) {
635 case HS_PRE_RUNNING:
636 handle_pre_remove_exit(status);
637 ret = 1;
638 break;
639 case HS_RUNNING:
640 ret = handle_rm_exit(status);
641 break;
642 case HS_POST_RUNNING:
643 handle_post_remove_exit();
644 ret = 1;
645 break;
646 default:
647 ret = -E_BUG;
648 }
649 if (snapshot_removal_status == HS_READY) {
650 free(s->name);
651 free(s);
652 snapshot_currently_being_removed = NULL;
653 }
654 remove_pid = 0;
655 return ret;
656 }
657
658 static int wait_for_remove_process(void)
659 {
660 int status, ret;
661
662 assert(remove_pid);
663 assert(
664 snapshot_removal_status == HS_PRE_RUNNING ||
665 snapshot_removal_status == HS_RUNNING ||
666 snapshot_removal_status == HS_POST_RUNNING
667 );
668 ret = wait_for_process(remove_pid, &status);
669 if (ret < 0)
670 return ret;
671 return handle_remove_exit(status);
672 }
673
674 static int handle_rsync_exit(int status)
675 {
676 int es, ret;
677
678 if (!WIFEXITED(status)) {
679 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
680 ret = -E_INVOLUNTARY_EXIT;
681 snapshot_creation_status = HS_READY;
682 goto out;
683 }
684 es = WEXITSTATUS(status);
685 /*
686 * Restart rsync on non-fatal errors:
687 * 12: Error in rsync protocol data stream
688 * 13: Errors with program diagnostics
689 */
690 if (es == 12 || es == 13) {
691 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
692 (int)create_pid, es);
693 snapshot_creation_status = HS_NEEDS_RESTART;
694 gettimeofday(&next_snapshot_time, NULL);
695 next_snapshot_time.tv_sec += 60;
696 ret = 1;
697 goto out;
698 }
699 if (es != 0 && es != 23 && es != 24) {
700 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
701 ret = -E_BAD_EXIT_CODE;
702 snapshot_creation_status = HS_READY;
703 goto out;
704 }
705 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
706 if (ret < 0)
707 goto out;
708 snapshot_creation_status = HS_SUCCESS;
709 out:
710 create_pid = 0;
711 create_process_stopped = 0;
712 return ret;
713 }
714
715 static int handle_pre_create_hook_exit(int status)
716 {
717 int es, ret;
718 static int warn_count;
719
720 if (!WIFEXITED(status)) {
721 snapshot_creation_status = HS_READY;
722 ret = -E_INVOLUNTARY_EXIT;
723 goto out;
724 }
725 es = WEXITSTATUS(status);
726 if (es) {
727 if (!warn_count--) {
728 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
729 conf.pre_create_hook_arg, es);
730 DSS_NOTICE_LOG("deferring snapshot creation...\n");
731 warn_count = 60; /* warn only once per hour */
732 }
733 snapshot_creation_status = HS_READY;
734 ret = 0;
735 goto out;
736 }
737 warn_count = 0;
738 snapshot_creation_status = HS_PRE_SUCCESS;
739 ret = 1;
740 out:
741 create_pid = 0;
742 return ret;
743 }
744
745 static int handle_sigchld(void)
746 {
747 pid_t pid;
748 int status, ret = reap_child(&pid, &status);
749
750 if (ret <= 0)
751 return ret;
752
753 if (pid == create_pid) {
754 switch (snapshot_creation_status) {
755 case HS_PRE_RUNNING:
756 return handle_pre_create_hook_exit(status);
757 case HS_RUNNING:
758 return handle_rsync_exit(status);
759 case HS_POST_RUNNING:
760 snapshot_creation_status = HS_READY;
761 return 1;
762 default:
763 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
764 snapshot_creation_status);
765 return -E_BUG;
766 }
767 }
768 if (pid == remove_pid) {
769 ret = handle_remove_exit(status);
770 if (ret < 0)
771 return ret;
772 return ret;
773 }
774 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
775 return -E_BUG;
776 }
777
778 static int check_config(void)
779 {
780 if (conf.unit_interval_arg <= 0) {
781 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
782 return -E_INVALID_NUMBER;
783 }
784 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
785 if (conf.num_intervals_arg <= 0) {
786 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
787 return -E_INVALID_NUMBER;
788 }
789 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
790 return 1;
791 }
792
793 static int parse_config_file(int override)
794 {
795 int ret;
796 char *config_file;
797 struct stat statbuf;
798 char *old_logfile_arg = NULL;
799 int old_daemon_given = 0;
800
801 if (conf.config_file_given)
802 config_file = dss_strdup(conf.config_file_arg);
803 else {
804 char *home = get_homedir();
805 config_file = make_message("%s/.dssrc", home);
806 free(home);
807 }
808 if (override) { /* SIGHUP */
809 if (conf.logfile_given)
810 old_logfile_arg = dss_strdup(conf.logfile_arg);
811 old_daemon_given = conf.daemon_given;
812 }
813
814 ret = stat(config_file, &statbuf);
815 if (ret && conf.config_file_given) {
816 ret = -ERRNO_TO_DSS_ERROR(errno);
817 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
818 goto out;
819 }
820 if (!ret) {
821 struct cmdline_parser_params params = {
822 .override = override,
823 .initialize = 0,
824 .check_required = 1,
825 .check_ambiguity = 0,
826 .print_errors = 1
827 };
828 if (override) { /* invalidate all rsync options */
829 int i;
830
831 for (i = 0; i < conf.rsync_option_given; i++) {
832 free(conf.rsync_option_arg[i]);
833 conf.rsync_option_arg[i] = NULL;
834 }
835 conf.rsync_option_given = 0;
836 }
837 cmdline_parser_config_file(config_file, &conf, &params);
838 }
839 ret = check_config();
840 if (ret < 0)
841 goto out;
842 if (override) {
843 /* don't change daemon mode on SIGHUP */
844 conf.daemon_given = old_daemon_given;
845 close_log(logfile);
846 logfile = NULL;
847 if (conf.logfile_given)
848 free(old_logfile_arg);
849 else if (conf.daemon_given) { /* re-use old logfile */
850 conf.logfile_arg = old_logfile_arg;
851 conf.logfile_given = 1;
852 }
853 }
854 if (conf.logfile_given) {
855 logfile = open_log(conf.logfile_arg);
856 log_welcome(conf.loglevel_arg);
857 }
858 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
859 // cmdline_parser_dump(logfile? logfile : stdout, &conf);
860 out:
861 free(config_file);
862 if (ret < 0)
863 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
864 return ret;
865 }
866
867 static int change_to_dest_dir(void)
868 {
869 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
870 return dss_chdir(conf.dest_dir_arg);
871 }
872
873 static int handle_sighup(void)
874 {
875 int ret;
876
877 DSS_NOTICE_LOG("SIGHUP\n");
878 ret = parse_config_file(1);
879 if (ret < 0)
880 return ret;
881 return change_to_dest_dir();
882 }
883
884 static int handle_signal(void)
885 {
886 int sig, ret = next_signal();
887
888 if (ret <= 0)
889 goto out;
890 sig = ret;
891 switch (sig) {
892 case SIGINT:
893 case SIGTERM:
894 restart_create_process();
895 kill_process(create_pid);
896 kill_process(remove_pid);
897 ret = -E_SIGNAL;
898 break;
899 case SIGHUP:
900 ret = handle_sighup();
901 break;
902 case SIGCHLD:
903 ret = handle_sigchld();
904 break;
905 }
906 out:
907 if (ret < 0)
908 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
909 return ret;
910 }
911
912 /*
913 * We can not use rsync locally if the local user is different from the remote
914 * user or if the src dir is not on the local host (or both).
915 */
916 static int use_rsync_locally(char *logname)
917 {
918 char *h = conf.remote_host_arg;
919
920 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
921 return 0;
922 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
923 return 0;
924 return 1;
925 }
926
927 static void create_rsync_argv(char ***argv, int64_t *num)
928 {
929 char *logname, *newest;
930 int i = 0, j;
931 struct snapshot_list sl;
932
933 dss_get_snapshot_list(&sl);
934 newest = name_of_newest_complete_snapshot(&sl);
935 free_snapshot_list(&sl);
936
937 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
938 (*argv)[i++] = dss_strdup("rsync");
939 (*argv)[i++] = dss_strdup("-aq");
940 (*argv)[i++] = dss_strdup("--delete");
941 for (j = 0; j < conf.rsync_option_given; j++)
942 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
943 if (newest) {
944 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
945 (*argv)[i++] = make_message("--link-dest=../%s", newest);
946 free(newest);
947 } else
948 DSS_INFO_LOG("no previous snapshot found\n");
949 logname = dss_logname();
950 if (use_rsync_locally(logname))
951 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
952 else
953 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
954 conf.remote_user_arg : logname,
955 conf.remote_host_arg, conf.source_dir_arg);
956 free(logname);
957 *num = get_current_time();
958 (*argv)[i++] = incomplete_name(*num);
959 (*argv)[i++] = NULL;
960 for (j = 0; j < i; j++)
961 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
962 }
963
964 static void free_rsync_argv(char **argv)
965 {
966 int i;
967
968 if (!argv)
969 return;
970 for (i = 0; argv[i]; i++)
971 free(argv[i]);
972 free(argv);
973 }
974
975 static int create_snapshot(char **argv)
976 {
977 int ret, fds[3] = {0, 0, 0};
978 char *name;
979
980 name = incomplete_name(current_snapshot_creation_time);
981 DSS_NOTICE_LOG("creating new snapshot %s\n", name);
982 free(name);
983 ret = dss_exec(&create_pid, argv[0], argv, fds);
984 if (ret < 0)
985 return ret;
986 snapshot_creation_status = HS_RUNNING;
987 return ret;
988 }
989
990 static int select_loop(void)
991 {
992 int ret;
993 /* check every 60 seconds for free disk space */
994 struct timeval tv;
995 char **rsync_argv = NULL;
996
997 for (;;) {
998 fd_set rfds;
999 int low_disk_space;
1000 struct timeval *tvp;
1001
1002 if (remove_pid)
1003 tvp = NULL; /* sleep until rm hook/process dies */
1004 else { /* sleep one minute */
1005 tv.tv_sec = 60;
1006 tv.tv_usec = 0;
1007 tvp = &tv;
1008 }
1009 FD_ZERO(&rfds);
1010 FD_SET(signal_pipe, &rfds);
1011 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1012 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1013 if (ret < 0)
1014 goto out;
1015 if (FD_ISSET(signal_pipe, &rfds)) {
1016 ret = handle_signal();
1017 if (ret < 0)
1018 goto out;
1019 }
1020 if (remove_pid)
1021 continue;
1022 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1023 ret = exec_rm();
1024 if (ret < 0)
1025 goto out;
1026 continue;
1027 }
1028 if (snapshot_removal_status == HS_SUCCESS) {
1029 ret = post_remove_hook();
1030 if (ret < 0)
1031 goto out;
1032 continue;
1033 }
1034 ret = disk_space_low();
1035 if (ret < 0)
1036 goto out;
1037 low_disk_space = ret;
1038 ret = try_to_free_disk_space(low_disk_space);
1039 if (ret < 0)
1040 goto out;
1041 if (snapshot_removal_status != HS_READY) {
1042 stop_create_process();
1043 continue;
1044 }
1045 restart_create_process();
1046 switch (snapshot_creation_status) {
1047 case HS_READY:
1048 if (!next_snapshot_is_due())
1049 continue;
1050 ret = pre_create_hook();
1051 if (ret < 0)
1052 goto out;
1053 continue;
1054 case HS_PRE_RUNNING:
1055 case HS_RUNNING:
1056 case HS_POST_RUNNING:
1057 continue;
1058 case HS_PRE_SUCCESS:
1059 free_rsync_argv(rsync_argv);
1060 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1061 /* fall through */
1062 case HS_NEEDS_RESTART:
1063 ret = create_snapshot(rsync_argv);
1064 if (ret < 0)
1065 goto out;
1066 continue;
1067 case HS_SUCCESS:
1068 ret = post_create_hook();
1069 if (ret < 0)
1070 goto out;
1071 continue;
1072 }
1073 }
1074 out:
1075 return ret;
1076 }
1077
1078 static void exit_hook(int exit_code)
1079 {
1080 int fds[3] = {0, 0, 0};
1081 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1082 pid_t pid;
1083
1084 if (!conf.exit_hook_given)
1085 return;
1086 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1087 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1088 }
1089
1090 static int com_run(void)
1091 {
1092 int ret;
1093
1094 if (conf.dry_run_given) {
1095 DSS_ERROR_LOG("dry_run not supported by this command\n");
1096 return -E_SYNTAX;
1097 }
1098 ret = install_sighandler(SIGHUP);
1099 if (ret < 0)
1100 return ret;
1101 ret = select_loop();
1102 if (ret >= 0) /* impossible */
1103 ret = -E_BUG;
1104 exit_hook(ret);
1105 return ret;
1106 }
1107
1108 static int com_prune(void)
1109 {
1110 int ret;
1111 struct snapshot_list sl;
1112 struct disk_space ds;
1113
1114 ret = get_disk_space(".", &ds);
1115 if (ret < 0)
1116 return ret;
1117 log_disk_space(&ds);
1118 dss_get_snapshot_list(&sl);
1119 ret = remove_outdated_snapshot(&sl);
1120 if (ret < 0)
1121 goto out;
1122 if (ret > 0)
1123 goto rm;
1124 ret = remove_redundant_snapshot(&sl);
1125 if (ret < 0)
1126 goto out;
1127 if (ret > 0)
1128 goto rm;
1129 ret = 0;
1130 goto out;
1131 rm:
1132 if (snapshot_removal_status == HS_PRE_RUNNING) {
1133 ret = wait_for_remove_process();
1134 if (ret < 0)
1135 goto out;
1136 if (snapshot_removal_status != HS_PRE_SUCCESS)
1137 goto out;
1138 }
1139 ret = exec_rm();
1140 if (ret < 0)
1141 goto out;
1142 ret = wait_for_remove_process();
1143 if (ret < 0)
1144 goto out;
1145 if (snapshot_removal_status != HS_SUCCESS)
1146 goto out;
1147 ret = post_remove_hook();
1148 if (ret < 0)
1149 goto out;
1150 if (snapshot_removal_status != HS_POST_RUNNING)
1151 goto out;
1152 ret = wait_for_remove_process();
1153 if (ret < 0)
1154 goto out;
1155 ret = 1;
1156 out:
1157 free_snapshot_list(&sl);
1158 return ret;
1159 }
1160
1161 static int com_create(void)
1162 {
1163 int ret, status;
1164 char **rsync_argv;
1165
1166 if (conf.dry_run_given) {
1167 int i;
1168 char *msg = NULL;
1169 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1170 for (i = 0; rsync_argv[i]; i++) {
1171 char *tmp = msg;
1172 msg = make_message("%s%s%s", tmp? tmp : "",
1173 tmp? " " : "", rsync_argv[i]);
1174 free(tmp);
1175 }
1176 free_rsync_argv(rsync_argv);
1177 dss_msg("%s\n", msg);
1178 free(msg);
1179 return 1;
1180 }
1181 ret = pre_create_hook();
1182 if (ret < 0)
1183 return ret;
1184 if (create_pid) {
1185 ret = wait_for_process(create_pid, &status);
1186 if (ret < 0)
1187 return ret;
1188 ret = handle_pre_create_hook_exit(status);
1189 if (ret <= 0) /* error, or pre-create failed */
1190 return ret;
1191 }
1192 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1193 ret = create_snapshot(rsync_argv);
1194 if (ret < 0)
1195 goto out;
1196 ret = wait_for_process(create_pid, &status);
1197 if (ret < 0)
1198 goto out;
1199 ret = handle_rsync_exit(status);
1200 if (ret < 0)
1201 goto out;
1202 post_create_hook();
1203 if (create_pid)
1204 ret = wait_for_process(create_pid, &status);
1205 out:
1206 free_rsync_argv(rsync_argv);
1207 return ret;
1208 }
1209
1210 static int com_ls(void)
1211 {
1212 int i;
1213 struct snapshot_list sl;
1214 struct snapshot *s;
1215
1216 dss_get_snapshot_list(&sl);
1217 FOR_EACH_SNAPSHOT(s, i, &sl) {
1218 int64_t d = 0;
1219 if (s->flags & SS_COMPLETE)
1220 d = (s->completion_time - s->creation_time) / 60;
1221 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1222 };
1223 free_snapshot_list(&sl);
1224 return 1;
1225 }
1226
1227 static int setup_signal_handling(void)
1228 {
1229 int ret;
1230
1231 DSS_INFO_LOG("setting up signal handlers\n");
1232 signal_pipe = signal_init(); /* always successful */
1233 ret = install_sighandler(SIGINT);
1234 if (ret < 0)
1235 return ret;
1236 ret = install_sighandler(SIGTERM);
1237 if (ret < 0)
1238 return ret;
1239 return install_sighandler(SIGCHLD);
1240 }
1241
1242 /**
1243 * The main function of dss.
1244 *
1245 * \param argc Usual argument count.
1246 * \param argv Usual argument vector.
1247 */
1248 int main(int argc, char **argv)
1249 {
1250 int ret;
1251 struct cmdline_parser_params params = {
1252 .override = 0,
1253 .initialize = 1,
1254 .check_required = 0,
1255 .check_ambiguity = 0,
1256 .print_errors = 1
1257 };
1258
1259 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1260 ret = parse_config_file(0);
1261 if (ret < 0)
1262 goto out;
1263 if (conf.daemon_given)
1264 daemon_init();
1265 ret = change_to_dest_dir();
1266 if (ret < 0)
1267 goto out;
1268 ret = setup_signal_handling();
1269 if (ret < 0)
1270 goto out;
1271 ret = call_command_handler();
1272 out:
1273 if (ret < 0)
1274 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1275 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1276 }