Move check for low disk space to try_to_free_disk_space().
[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 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 static char *name_of_reference_snapshot;
60 /** \sa \ref snap.h for details. */
61 enum hook_status snapshot_creation_status;
62 /** \sa \ref snap.h for details. */
63 enum hook_status snapshot_removal_status;
64
65
66 DEFINE_DSS_ERRLIST;
67
68
69 /* a litte cpp magic helps to DRY */
70 #define COMMANDS \
71 COMMAND(ls) \
72 COMMAND(create) \
73 COMMAND(prune) \
74 COMMAND(run)
75 #define COMMAND(x) static int com_ ##x(void);
76 COMMANDS
77 #undef COMMAND
78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
79 static int call_command_handler(void)
80 {
81 COMMANDS
82 DSS_EMERG_LOG("BUG: did not find command handler\n");
83 return -E_BUG;
84 }
85 #undef COMMAND
86 #undef COMMANDS
87
88 /**
89 * The log function of dss.
90 *
91 * \param ll Loglevel.
92 * \param fml Usual format string.
93 *
94 * All DSS_XXX_LOG() macros use this function.
95 */
96 __printf_2_3 void dss_log(int ll, const char* fmt,...)
97 {
98 va_list argp;
99 FILE *outfd;
100 struct tm *tm;
101 time_t t1;
102 char str[255] = "";
103
104 if (ll < conf.loglevel_arg)
105 return;
106 outfd = logfile? logfile : stderr;
107 time(&t1);
108 tm = localtime(&t1);
109 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
110 fprintf(outfd, "%s ", str);
111 if (conf.loglevel_arg <= INFO)
112 fprintf(outfd, "%i: ", ll);
113 va_start(argp, fmt);
114 vfprintf(outfd, fmt, argp);
115 va_end(argp);
116 }
117
118 /**
119 * Print a message either to stdout or to the log file.
120 */
121 static __printf_1_2 void dss_msg(const char* fmt,...)
122 {
123 FILE *outfd = conf.daemon_given? logfile : stdout;
124 va_list argp;
125 va_start(argp, fmt);
126 vfprintf(outfd, fmt, argp);
127 va_end(argp);
128 }
129
130 static int disk_space_low(void)
131 {
132 struct disk_space ds;
133 int ret = get_disk_space(".", &ds);
134
135 if (ret < 0)
136 return ret;
137 if (conf.min_free_mb_arg)
138 if (ds.free_mb < conf.min_free_mb_arg)
139 return 1;
140 if (conf.min_free_percent_arg)
141 if (ds.percent_free < conf.min_free_percent_arg)
142 return 1;
143 if (conf.min_free_percent_inodes_arg)
144 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
145 return 1;
146 return 0;
147 }
148
149 static void dss_get_snapshot_list(struct snapshot_list *sl)
150 {
151 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
152 }
153
154 static int next_snapshot_is_due(void)
155 {
156 struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
157 tmp, diff;
158 int64_t x = 0;
159 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
160 num_complete_snapshots = 0;
161 int i, ret;
162 struct snapshot *s = NULL;
163 struct snapshot_list sl;
164
165 gettimeofday(&now, NULL);
166 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
167 return 0;
168 assert(snapshot_creation_status == HS_READY);
169 current_snapshot_creation_time = 0;
170 dss_get_snapshot_list(&sl);
171 FOR_EACH_SNAPSHOT(s, i, &sl) {
172 if (!(s->flags & SS_COMPLETE))
173 continue;
174 num_complete_snapshots++;
175 x += s->completion_time - s->creation_time;
176 }
177 assert(x >= 0);
178 if (num_complete_snapshots)
179 x /= num_complete_snapshots; /* avg time to create one snapshot */
180 x *= wanted; /* time to create all snapshots in interval 0 */
181 tmp.tv_sec = x;
182 tmp.tv_usec = 0;
183 ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
184 if (ret < 0 || !s) { /* unit_interval < tmp or no snapshot */
185 ret = 1;
186 goto out;
187 }
188
189 tv_divide(wanted, &diff, &tmp); /* sleep time between two snapshots */
190 diff.tv_sec = s->completion_time; /* completion time of the latest snapshot */
191 diff.tv_usec = 0;
192 tv_add(&diff, &tmp, &next_snapshot_time);
193 ret = (tv_diff(&now, &next_snapshot_time, &diff) < 0)? 0 : 1;
194 out:
195 free_snapshot_list(&sl);
196 if (ret == 0)
197 DSS_DEBUG_LOG("next snapshot due in %lu seconds\n",
198 tv2ms(&diff) / 1000);
199 else
200 DSS_DEBUG_LOG("next snapshot: now\n");
201 return ret;
202 }
203
204 static int pre_create_hook(void)
205 {
206 int ret, fds[3] = {0, 0, 0};
207
208 assert(snapshot_creation_status == HS_READY);
209 if (!conf.pre_create_hook_given) {
210 snapshot_creation_status = HS_PRE_SUCCESS;
211 return 0;
212 }
213 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
214 ret = dss_exec_cmdline_pid(&create_pid,
215 conf.pre_create_hook_arg, fds);
216 if (ret < 0)
217 return ret;
218 snapshot_creation_status = HS_PRE_RUNNING;
219 return ret;
220 }
221
222 static int pre_remove_hook(struct snapshot *s, const char *why)
223 {
224 int ret, fds[3] = {0, 0, 0};
225 char *cmd;
226
227 if (!s)
228 return 0;
229 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
230 assert(snapshot_removal_status == HS_READY);
231 assert(remove_pid == 0);
232 assert(!snapshot_currently_being_removed);
233
234 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
235 *snapshot_currently_being_removed = *s;
236 snapshot_currently_being_removed->name = dss_strdup(s->name);
237
238 if (!conf.pre_remove_hook_given) {
239 snapshot_removal_status = HS_PRE_SUCCESS;
240 return 0;
241 }
242 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
243 conf.dest_dir_arg, s->name);
244 DSS_DEBUG_LOG("executing %s\n", cmd);
245 ret = dss_exec_cmdline_pid(&remove_pid,
246 conf.pre_remove_hook_arg, fds);
247 free(cmd);
248 if (ret < 0)
249 return ret;
250 snapshot_removal_status = HS_PRE_RUNNING;
251 return ret;
252 }
253
254 static int exec_rm(void)
255 {
256 struct snapshot *s = snapshot_currently_being_removed;
257 int fds[3] = {0, 0, 0};
258 char *new_name = being_deleted_name(s);
259 char *argv[] = {"rm", "-rf", new_name, NULL};
260 int ret;
261
262 assert(snapshot_removal_status == HS_PRE_SUCCESS);
263 assert(remove_pid == 0);
264
265 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
266 ret = dss_rename(s->name, new_name);
267 if (ret < 0)
268 goto out;
269 ret = dss_exec(&remove_pid, argv[0], argv, fds);
270 if (ret < 0)
271 goto out;
272 snapshot_removal_status = HS_RUNNING;
273 out:
274 free(new_name);
275 return ret;
276 }
277
278 static int snapshot_is_being_created(struct snapshot *s)
279 {
280 return s->creation_time == current_snapshot_creation_time;
281 }
282
283 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
284 {
285 struct snapshot *s;
286 int i;
287
288 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
289 FOR_EACH_SNAPSHOT(s, i, sl) {
290 if (snapshot_is_being_created(s))
291 continue;
292 /*
293 * We know that no rm is currently running, so if s is marked
294 * as being deleted, a previously started rm must have failed.
295 */
296 if (s->flags & SS_BEING_DELETED)
297 return s;
298
299 if (s->flags & SS_COMPLETE) /* good snapshot */
300 continue;
301 /*
302 * This snapshot is incomplete and it is not the snapshot
303 * currently being created. However, we must not remove it if
304 * rsync is about to be restarted. As only the newest snapshot
305 * can be restarted, this snapshot is orphaned if it is not the
306 * newest snapshot or if we are not about to restart rsync.
307 */
308 if (get_newest_snapshot(sl) != s)
309 return s;
310 if (snapshot_creation_status != HS_NEEDS_RESTART)
311 return s;
312 }
313 /* no orphaned snapshots */
314 return NULL;
315 }
316
317 static int is_reference_snapshot(struct snapshot *s)
318 {
319 if (!name_of_reference_snapshot)
320 return 0;
321 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
322 }
323
324 /*
325 * return: 0: no redundant snapshots, 1: rm process started, negative: error
326 */
327 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
328 {
329 int i, interval;
330 struct snapshot *s;
331 unsigned missing = 0;
332
333 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
334 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
335 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
336 unsigned num = sl->interval_count[interval];
337 struct snapshot *victim = NULL, *prev = NULL;
338 int64_t score = LONG_MAX;
339
340 if (keep >= num)
341 missing += keep - num;
342 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
343 // interval, keep, num, missing);
344 if (keep + missing >= num)
345 continue;
346 /* redundant snapshot in this interval, pick snapshot with lowest score */
347 FOR_EACH_SNAPSHOT(s, i, sl) {
348 int64_t this_score;
349
350 if (snapshot_is_being_created(s))
351 continue;
352 if (is_reference_snapshot(s))
353 continue;
354 //DSS_DEBUG_LOG("checking %s\n", s->name);
355 if (s->interval > interval) {
356 prev = s;
357 continue;
358 }
359 if (s->interval < interval)
360 break;
361 if (!victim) {
362 victim = s;
363 prev = s;
364 continue;
365 }
366 assert(prev);
367 /* check if s is a better victim */
368 this_score = s->creation_time - prev->creation_time;
369 assert(this_score >= 0);
370 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
371 if (this_score < score) {
372 score = this_score;
373 victim = s;
374 }
375 prev = s;
376 }
377 assert(victim);
378 return victim;
379 }
380 return NULL;
381 }
382
383 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
384 {
385 int i;
386 struct snapshot *s;
387
388 DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
389 conf.num_intervals_arg);
390 FOR_EACH_SNAPSHOT(s, i, sl) {
391 if (snapshot_is_being_created(s))
392 continue;
393 if (is_reference_snapshot(s))
394 continue;
395 if (s->interval <= conf.num_intervals_arg)
396 continue;
397 return s;
398 }
399 return NULL;
400 }
401
402 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
403 {
404 int i;
405 struct snapshot *s;
406 FOR_EACH_SNAPSHOT(s, i, sl) {
407 if (snapshot_is_being_created(s))
408 continue;
409 if (is_reference_snapshot(s))
410 continue;
411 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
412 return s;
413 }
414 return NULL;
415 }
416
417 static int rename_incomplete_snapshot(int64_t start)
418 {
419 char *old_name;
420 int ret;
421
422 free(path_to_last_complete_snapshot);
423 ret = complete_name(start, get_current_time(),
424 &path_to_last_complete_snapshot);
425 if (ret < 0)
426 return ret;
427 old_name = incomplete_name(start);
428 ret = dss_rename(old_name, path_to_last_complete_snapshot);
429 if (ret >= 0)
430 DSS_NOTICE_LOG("%s -> %s\n", old_name,
431 path_to_last_complete_snapshot);
432 free(old_name);
433 return ret;
434 }
435
436 static int try_to_free_disk_space(void)
437 {
438 int ret;
439 struct snapshot_list sl;
440 struct snapshot *victim;
441 struct timeval now;
442 const char *why;
443 int low_disk_space;
444
445 ret = disk_space_low();
446 if (ret < 0)
447 return ret;
448 low_disk_space = ret;
449 gettimeofday(&now, NULL);
450 if (tv_diff(&next_removal_check, &now, NULL) > 0)
451 return 0;
452 if (!low_disk_space && conf.keep_redundant_given)
453 return 0;
454 dss_get_snapshot_list(&sl);
455 ret = 0;
456 if (!low_disk_space && sl.num_snapshots <= 1)
457 goto out;
458 why = "outdated";
459 victim = find_outdated_snapshot(&sl);
460 if (victim)
461 goto remove;
462 why = "redundant";
463 victim = find_redundant_snapshot(&sl);
464 if (victim)
465 goto remove;
466 /* try harder only if disk space is low */
467 if (!low_disk_space)
468 goto out;
469 why = "orphaned";
470 victim = find_orphaned_snapshot(&sl);
471 if (victim)
472 goto remove;
473 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
474 victim = find_oldest_removable_snapshot(&sl);
475 if (victim)
476 goto remove;
477 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
478 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
479 goto out;
480 remove:
481 ret = pre_remove_hook(victim, why);
482 out:
483 free_snapshot_list(&sl);
484 return ret;
485 }
486
487 static int post_create_hook(void)
488 {
489 int ret, fds[3] = {0, 0, 0};
490 char *cmd;
491
492 if (!conf.post_create_hook_given) {
493 snapshot_creation_status = HS_READY;
494 return 0;
495 }
496 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
497 conf.dest_dir_arg, path_to_last_complete_snapshot);
498 DSS_NOTICE_LOG("executing %s\n", cmd);
499 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
500 free(cmd);
501 if (ret < 0)
502 return ret;
503 snapshot_creation_status = HS_POST_RUNNING;
504 return ret;
505 }
506
507 static int post_remove_hook(void)
508 {
509 int ret, fds[3] = {0, 0, 0};
510 char *cmd;
511 struct snapshot *s = snapshot_currently_being_removed;
512
513 assert(s);
514
515 if (!conf.post_remove_hook_given) {
516 snapshot_removal_status = HS_READY;
517 return 0;
518 }
519 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
520 conf.dest_dir_arg, s->name);
521 DSS_NOTICE_LOG("executing %s\n", cmd);
522 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
523 free(cmd);
524 if (ret < 0)
525 return ret;
526 snapshot_removal_status = HS_POST_RUNNING;
527 return ret;
528 }
529
530 static void kill_process(pid_t pid)
531 {
532 if (!pid)
533 return;
534 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
535 kill(pid, SIGTERM);
536 }
537
538 static void stop_create_process(void)
539 {
540 if (!create_pid || create_process_stopped)
541 return;
542 kill(SIGSTOP, create_pid);
543 create_process_stopped = 1;
544 }
545
546 static void restart_create_process(void)
547 {
548 if (!create_pid || !create_process_stopped)
549 return;
550 kill (SIGCONT, create_pid);
551 create_process_stopped = 0;
552 }
553
554 /**
555 * Print a log message about the exit status of a child.
556 */
557 static void log_termination_msg(pid_t pid, int status)
558 {
559 if (WIFEXITED(status))
560 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
561 WEXITSTATUS(status));
562 else if (WIFSIGNALED(status))
563 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
564 WTERMSIG(status));
565 else
566 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
567 }
568
569 static int wait_for_process(pid_t pid, int *status)
570 {
571 int ret;
572
573 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
574 for (;;) {
575 fd_set rfds;
576
577 FD_ZERO(&rfds);
578 FD_SET(signal_pipe, &rfds);
579 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
580 if (ret < 0)
581 break;
582 ret = next_signal();
583 if (!ret)
584 continue;
585 if (ret == SIGCHLD) {
586 ret = waitpid(pid, status, 0);
587 if (ret >= 0)
588 break;
589 if (errno != EINTR) { /* error */
590 ret = -ERRNO_TO_DSS_ERROR(errno);
591 break;
592 }
593 }
594 /* SIGINT or SIGTERM */
595 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
596 kill(pid, SIGTERM);
597 }
598 if (ret < 0)
599 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
600 else
601 log_termination_msg(pid, *status);
602 return ret;
603 }
604
605 static void handle_pre_remove_exit(int status)
606 {
607 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
608 snapshot_removal_status = HS_READY;
609 gettimeofday(&next_removal_check, NULL);
610 next_removal_check.tv_sec += 60;
611 return;
612 }
613 snapshot_removal_status = HS_PRE_SUCCESS;
614 }
615
616 static int handle_rm_exit(int status)
617 {
618 if (!WIFEXITED(status)) {
619 snapshot_removal_status = HS_READY;
620 return -E_INVOLUNTARY_EXIT;
621 }
622 if (WEXITSTATUS(status)) {
623 snapshot_removal_status = HS_READY;
624 return -E_BAD_EXIT_CODE;
625 }
626 if (conf.post_remove_hook_given)
627 snapshot_removal_status = HS_SUCCESS;
628 else
629 snapshot_removal_status = HS_READY;
630 return 1;
631 }
632
633 static void handle_post_remove_exit(void)
634 {
635 snapshot_removal_status = HS_READY;
636 }
637
638 static int handle_remove_exit(int status)
639 {
640 int ret;
641 struct snapshot *s = snapshot_currently_being_removed;
642
643 assert(s);
644 switch (snapshot_removal_status) {
645 case HS_PRE_RUNNING:
646 handle_pre_remove_exit(status);
647 ret = 1;
648 break;
649 case HS_RUNNING:
650 ret = handle_rm_exit(status);
651 break;
652 case HS_POST_RUNNING:
653 handle_post_remove_exit();
654 ret = 1;
655 break;
656 default:
657 ret = -E_BUG;
658 }
659 if (snapshot_removal_status == HS_READY) {
660 free(s->name);
661 free(s);
662 snapshot_currently_being_removed = NULL;
663 }
664 remove_pid = 0;
665 return ret;
666 }
667
668 static int wait_for_remove_process(void)
669 {
670 int status, ret;
671
672 assert(remove_pid);
673 assert(
674 snapshot_removal_status == HS_PRE_RUNNING ||
675 snapshot_removal_status == HS_RUNNING ||
676 snapshot_removal_status == HS_POST_RUNNING
677 );
678 ret = wait_for_process(remove_pid, &status);
679 if (ret < 0)
680 return ret;
681 return handle_remove_exit(status);
682 }
683
684 static int handle_rsync_exit(int status)
685 {
686 int es, ret;
687
688 if (!WIFEXITED(status)) {
689 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
690 ret = -E_INVOLUNTARY_EXIT;
691 snapshot_creation_status = HS_READY;
692 goto out;
693 }
694 es = WEXITSTATUS(status);
695 /*
696 * Restart rsync on non-fatal errors:
697 * 12: Error in rsync protocol data stream
698 * 13: Errors with program diagnostics
699 */
700 if (es == 12 || es == 13) {
701 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
702 (int)create_pid, es);
703 snapshot_creation_status = HS_NEEDS_RESTART;
704 gettimeofday(&next_snapshot_time, NULL);
705 next_snapshot_time.tv_sec += 60;
706 ret = 1;
707 goto out;
708 }
709 if (es != 0 && es != 23 && es != 24) {
710 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
711 ret = -E_BAD_EXIT_CODE;
712 snapshot_creation_status = HS_READY;
713 goto out;
714 }
715 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
716 if (ret < 0)
717 goto out;
718 snapshot_creation_status = HS_SUCCESS;
719 free(name_of_reference_snapshot);
720 name_of_reference_snapshot = NULL;
721 out:
722 create_pid = 0;
723 create_process_stopped = 0;
724 return ret;
725 }
726
727 static int handle_pre_create_hook_exit(int status)
728 {
729 int es, ret;
730 static int warn_count;
731
732 if (!WIFEXITED(status)) {
733 snapshot_creation_status = HS_READY;
734 ret = -E_INVOLUNTARY_EXIT;
735 goto out;
736 }
737 es = WEXITSTATUS(status);
738 if (es) {
739 if (!warn_count--) {
740 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
741 conf.pre_create_hook_arg, es);
742 DSS_NOTICE_LOG("deferring snapshot creation...\n");
743 warn_count = 60; /* warn only once per hour */
744 }
745 gettimeofday(&next_snapshot_time, NULL);
746 next_snapshot_time.tv_sec += 60;
747 snapshot_creation_status = HS_READY;
748 ret = 0;
749 goto out;
750 }
751 warn_count = 0;
752 snapshot_creation_status = HS_PRE_SUCCESS;
753 ret = 1;
754 out:
755 create_pid = 0;
756 return ret;
757 }
758
759 static int handle_sigchld(void)
760 {
761 pid_t pid;
762 int status, ret = reap_child(&pid, &status);
763
764 if (ret <= 0)
765 return ret;
766
767 if (pid == create_pid) {
768 switch (snapshot_creation_status) {
769 case HS_PRE_RUNNING:
770 return handle_pre_create_hook_exit(status);
771 case HS_RUNNING:
772 return handle_rsync_exit(status);
773 case HS_POST_RUNNING:
774 snapshot_creation_status = HS_READY;
775 return 1;
776 default:
777 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
778 snapshot_creation_status);
779 return -E_BUG;
780 }
781 }
782 if (pid == remove_pid) {
783 ret = handle_remove_exit(status);
784 if (ret < 0)
785 return ret;
786 return ret;
787 }
788 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
789 return -E_BUG;
790 }
791
792 static int check_config(void)
793 {
794 if (conf.unit_interval_arg <= 0) {
795 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
796 return -E_INVALID_NUMBER;
797 }
798 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
799 if (conf.num_intervals_arg <= 0) {
800 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
801 return -E_INVALID_NUMBER;
802 }
803 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
804 return 1;
805 }
806
807 static int parse_config_file(int override)
808 {
809 int ret;
810 char *config_file;
811 struct stat statbuf;
812 char *old_logfile_arg = NULL;
813 int old_daemon_given = 0;
814
815 if (conf.config_file_given)
816 config_file = dss_strdup(conf.config_file_arg);
817 else {
818 char *home = get_homedir();
819 config_file = make_message("%s/.dssrc", home);
820 free(home);
821 }
822 if (override) { /* SIGHUP */
823 if (conf.logfile_given)
824 old_logfile_arg = dss_strdup(conf.logfile_arg);
825 old_daemon_given = conf.daemon_given;
826 }
827
828 ret = stat(config_file, &statbuf);
829 if (ret && conf.config_file_given) {
830 ret = -ERRNO_TO_DSS_ERROR(errno);
831 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
832 goto out;
833 }
834 if (!ret) {
835 struct cmdline_parser_params params = {
836 .override = override,
837 .initialize = 0,
838 .check_required = 1,
839 .check_ambiguity = 0,
840 .print_errors = 1
841 };
842 if (override) { /* invalidate all rsync options */
843 int i;
844
845 for (i = 0; i < conf.rsync_option_given; i++) {
846 free(conf.rsync_option_arg[i]);
847 conf.rsync_option_arg[i] = NULL;
848 }
849 conf.rsync_option_given = 0;
850 }
851 cmdline_parser_config_file(config_file, &conf, &params);
852 }
853 ret = check_config();
854 if (ret < 0)
855 goto out;
856 if (override) {
857 /* don't change daemon mode on SIGHUP */
858 conf.daemon_given = old_daemon_given;
859 close_log(logfile);
860 logfile = NULL;
861 if (conf.logfile_given)
862 free(old_logfile_arg);
863 else if (conf.daemon_given) { /* re-use old logfile */
864 conf.logfile_arg = old_logfile_arg;
865 conf.logfile_given = 1;
866 }
867 }
868 if (conf.logfile_given) {
869 logfile = open_log(conf.logfile_arg);
870 log_welcome(conf.loglevel_arg);
871 }
872 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
873 // cmdline_parser_dump(logfile? logfile : stdout, &conf);
874 out:
875 free(config_file);
876 if (ret < 0)
877 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
878 return ret;
879 }
880
881 static int change_to_dest_dir(void)
882 {
883 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
884 return dss_chdir(conf.dest_dir_arg);
885 }
886
887 static int handle_sighup(void)
888 {
889 int ret;
890
891 DSS_NOTICE_LOG("SIGHUP\n");
892 ret = parse_config_file(1);
893 if (ret < 0)
894 return ret;
895 return change_to_dest_dir();
896 }
897
898 static int handle_signal(void)
899 {
900 int sig, ret = next_signal();
901
902 if (ret <= 0)
903 goto out;
904 sig = ret;
905 switch (sig) {
906 case SIGINT:
907 case SIGTERM:
908 restart_create_process();
909 kill_process(create_pid);
910 kill_process(remove_pid);
911 ret = -E_SIGNAL;
912 break;
913 case SIGHUP:
914 ret = handle_sighup();
915 break;
916 case SIGCHLD:
917 ret = handle_sigchld();
918 break;
919 }
920 out:
921 if (ret < 0)
922 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
923 return ret;
924 }
925
926 /*
927 * We can not use rsync locally if the local user is different from the remote
928 * user or if the src dir is not on the local host (or both).
929 */
930 static int use_rsync_locally(char *logname)
931 {
932 char *h = conf.remote_host_arg;
933
934 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
935 return 0;
936 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
937 return 0;
938 return 1;
939 }
940
941 static void create_rsync_argv(char ***argv, int64_t *num)
942 {
943 char *logname;
944 int i = 0, j;
945 struct snapshot_list sl;
946
947 dss_get_snapshot_list(&sl);
948 assert(!name_of_reference_snapshot);
949 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
950 free_snapshot_list(&sl);
951
952 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
953 (*argv)[i++] = dss_strdup("rsync");
954 (*argv)[i++] = dss_strdup("-aq");
955 (*argv)[i++] = dss_strdup("--delete");
956 for (j = 0; j < conf.rsync_option_given; j++)
957 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
958 if (name_of_reference_snapshot) {
959 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
960 (*argv)[i++] = make_message("--link-dest=../%s",
961 name_of_reference_snapshot);
962 } else
963 DSS_INFO_LOG("no suitable reference snapshot found\n");
964 logname = dss_logname();
965 if (use_rsync_locally(logname))
966 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
967 else
968 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
969 conf.remote_user_arg : logname,
970 conf.remote_host_arg, conf.source_dir_arg);
971 free(logname);
972 *num = get_current_time();
973 (*argv)[i++] = incomplete_name(*num);
974 (*argv)[i++] = NULL;
975 for (j = 0; j < i; j++)
976 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
977 }
978
979 static void free_rsync_argv(char **argv)
980 {
981 int i;
982
983 if (!argv)
984 return;
985 for (i = 0; argv[i]; i++)
986 free(argv[i]);
987 free(argv);
988 }
989
990 static int create_snapshot(char **argv)
991 {
992 int ret, fds[3] = {0, 0, 0};
993 char *name;
994
995 name = incomplete_name(current_snapshot_creation_time);
996 DSS_NOTICE_LOG("creating new snapshot %s\n", name);
997 free(name);
998 ret = dss_exec(&create_pid, argv[0], argv, fds);
999 if (ret < 0)
1000 return ret;
1001 snapshot_creation_status = HS_RUNNING;
1002 return ret;
1003 }
1004
1005 static int select_loop(void)
1006 {
1007 int ret;
1008 /* check every 60 seconds for free disk space */
1009 struct timeval tv;
1010 char **rsync_argv = NULL;
1011
1012 for (;;) {
1013 fd_set rfds;
1014 struct timeval *tvp;
1015
1016 if (remove_pid)
1017 tvp = NULL; /* sleep until rm hook/process dies */
1018 else { /* sleep one minute */
1019 tv.tv_sec = 60;
1020 tv.tv_usec = 0;
1021 tvp = &tv;
1022 }
1023 FD_ZERO(&rfds);
1024 FD_SET(signal_pipe, &rfds);
1025 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1026 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1027 if (ret < 0)
1028 goto out;
1029 if (FD_ISSET(signal_pipe, &rfds)) {
1030 ret = handle_signal();
1031 if (ret < 0)
1032 goto out;
1033 }
1034 if (remove_pid)
1035 continue;
1036 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1037 ret = exec_rm();
1038 if (ret < 0)
1039 goto out;
1040 continue;
1041 }
1042 if (snapshot_removal_status == HS_SUCCESS) {
1043 ret = post_remove_hook();
1044 if (ret < 0)
1045 goto out;
1046 continue;
1047 }
1048 ret = try_to_free_disk_space();
1049 if (ret < 0)
1050 goto out;
1051 if (snapshot_removal_status != HS_READY) {
1052 stop_create_process();
1053 continue;
1054 }
1055 restart_create_process();
1056 switch (snapshot_creation_status) {
1057 case HS_READY:
1058 if (!next_snapshot_is_due())
1059 continue;
1060 ret = pre_create_hook();
1061 if (ret < 0)
1062 goto out;
1063 continue;
1064 case HS_PRE_RUNNING:
1065 case HS_RUNNING:
1066 case HS_POST_RUNNING:
1067 continue;
1068 case HS_PRE_SUCCESS:
1069 free_rsync_argv(rsync_argv);
1070 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1071 /* fall through */
1072 case HS_NEEDS_RESTART:
1073 ret = create_snapshot(rsync_argv);
1074 if (ret < 0)
1075 goto out;
1076 continue;
1077 case HS_SUCCESS:
1078 ret = post_create_hook();
1079 if (ret < 0)
1080 goto out;
1081 continue;
1082 }
1083 }
1084 out:
1085 return ret;
1086 }
1087
1088 static void exit_hook(int exit_code)
1089 {
1090 int fds[3] = {0, 0, 0};
1091 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1092 pid_t pid;
1093
1094 if (!conf.exit_hook_given)
1095 return;
1096 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1097 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1098 }
1099
1100 static int com_run(void)
1101 {
1102 int ret;
1103
1104 if (conf.dry_run_given) {
1105 DSS_ERROR_LOG("dry_run not supported by this command\n");
1106 return -E_SYNTAX;
1107 }
1108 ret = install_sighandler(SIGHUP);
1109 if (ret < 0)
1110 return ret;
1111 ret = select_loop();
1112 if (ret >= 0) /* impossible */
1113 ret = -E_BUG;
1114 exit_hook(ret);
1115 return ret;
1116 }
1117
1118 static int com_prune(void)
1119 {
1120 int ret;
1121 struct snapshot_list sl;
1122 struct snapshot *victim;
1123 struct disk_space ds;
1124 const char *why;
1125
1126 ret = get_disk_space(".", &ds);
1127 if (ret < 0)
1128 return ret;
1129 log_disk_space(&ds);
1130 dss_get_snapshot_list(&sl);
1131 why = "outdated";
1132 victim = find_outdated_snapshot(&sl);
1133 if (victim)
1134 goto rm;
1135 why = "redundant";
1136 victim = find_redundant_snapshot(&sl);
1137 if (victim)
1138 goto rm;
1139 ret = 0;
1140 goto out;
1141 rm:
1142 if (conf.dry_run_given) {
1143 dss_msg("%s snapshot %s (interval = %i)\n",
1144 why, victim->name, victim->interval);
1145 ret = 0;
1146 goto out;
1147 }
1148 ret = pre_remove_hook(victim, why);
1149 if (ret < 0)
1150 goto out;
1151 if (snapshot_removal_status == HS_PRE_RUNNING) {
1152 ret = wait_for_remove_process();
1153 if (ret < 0)
1154 goto out;
1155 if (snapshot_removal_status != HS_PRE_SUCCESS)
1156 goto out;
1157 }
1158 ret = exec_rm();
1159 if (ret < 0)
1160 goto out;
1161 ret = wait_for_remove_process();
1162 if (ret < 0)
1163 goto out;
1164 if (snapshot_removal_status != HS_SUCCESS)
1165 goto out;
1166 ret = post_remove_hook();
1167 if (ret < 0)
1168 goto out;
1169 if (snapshot_removal_status != HS_POST_RUNNING)
1170 goto out;
1171 ret = wait_for_remove_process();
1172 if (ret < 0)
1173 goto out;
1174 ret = 1;
1175 out:
1176 free_snapshot_list(&sl);
1177 return ret;
1178 }
1179
1180 static int com_create(void)
1181 {
1182 int ret, status;
1183 char **rsync_argv;
1184
1185 if (conf.dry_run_given) {
1186 int i;
1187 char *msg = NULL;
1188 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1189 for (i = 0; rsync_argv[i]; i++) {
1190 char *tmp = msg;
1191 msg = make_message("%s%s%s", tmp? tmp : "",
1192 tmp? " " : "", rsync_argv[i]);
1193 free(tmp);
1194 }
1195 free_rsync_argv(rsync_argv);
1196 dss_msg("%s\n", msg);
1197 free(msg);
1198 return 1;
1199 }
1200 ret = pre_create_hook();
1201 if (ret < 0)
1202 return ret;
1203 if (create_pid) {
1204 ret = wait_for_process(create_pid, &status);
1205 if (ret < 0)
1206 return ret;
1207 ret = handle_pre_create_hook_exit(status);
1208 if (ret <= 0) /* error, or pre-create failed */
1209 return ret;
1210 }
1211 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1212 ret = create_snapshot(rsync_argv);
1213 if (ret < 0)
1214 goto out;
1215 ret = wait_for_process(create_pid, &status);
1216 if (ret < 0)
1217 goto out;
1218 ret = handle_rsync_exit(status);
1219 if (ret < 0)
1220 goto out;
1221 post_create_hook();
1222 if (create_pid)
1223 ret = wait_for_process(create_pid, &status);
1224 out:
1225 free_rsync_argv(rsync_argv);
1226 return ret;
1227 }
1228
1229 static int com_ls(void)
1230 {
1231 int i;
1232 struct snapshot_list sl;
1233 struct snapshot *s;
1234
1235 dss_get_snapshot_list(&sl);
1236 FOR_EACH_SNAPSHOT(s, i, &sl) {
1237 int64_t d = 0;
1238 if (s->flags & SS_COMPLETE)
1239 d = (s->completion_time - s->creation_time) / 60;
1240 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1241 };
1242 free_snapshot_list(&sl);
1243 return 1;
1244 }
1245
1246 static int setup_signal_handling(void)
1247 {
1248 int ret;
1249
1250 DSS_INFO_LOG("setting up signal handlers\n");
1251 signal_pipe = signal_init(); /* always successful */
1252 ret = install_sighandler(SIGINT);
1253 if (ret < 0)
1254 return ret;
1255 ret = install_sighandler(SIGTERM);
1256 if (ret < 0)
1257 return ret;
1258 return install_sighandler(SIGCHLD);
1259 }
1260
1261 /**
1262 * The main function of dss.
1263 *
1264 * \param argc Usual argument count.
1265 * \param argv Usual argument vector.
1266 */
1267 int main(int argc, char **argv)
1268 {
1269 int ret;
1270 struct cmdline_parser_params params = {
1271 .override = 0,
1272 .initialize = 1,
1273 .check_required = 0,
1274 .check_ambiguity = 0,
1275 .print_errors = 1
1276 };
1277
1278 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1279 ret = parse_config_file(0);
1280 if (ret < 0)
1281 goto out;
1282 if (conf.daemon_given)
1283 daemon_init();
1284 ret = change_to_dest_dir();
1285 if (ret < 0)
1286 goto out;
1287 ret = setup_signal_handling();
1288 if (ret < 0)
1289 goto out;
1290 ret = call_command_handler();
1291 out:
1292 if (ret < 0)
1293 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1294 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1295 }