Properly invalidate create_pid also for the post-create hook.
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6 #include <string.h>
7 #include <stdlib.h>
8 #include <stdarg.h>
9 #include <assert.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <signal.h>
13 #include <ctype.h>
14 #include <sys/stat.h>
15 #include <unistd.h>
16 #include <inttypes.h>
17 #include <sys/time.h>
18 #include <time.h>
19 #include <sys/wait.h>
20 #include <fnmatch.h>
21 #include <limits.h>
22
23
24 #include "gcc-compat.h"
25 #include "cmdline.h"
26 #include "log.h"
27 #include "string.h"
28 #include "error.h"
29 #include "fd.h"
30 #include "exec.h"
31 #include "daemon.h"
32 #include "signal.h"
33 #include "df.h"
34 #include "time.h"
35 #include "snap.h"
36
37 /** Command line and config file options. */
38 static struct gengetopt_args_info conf;
39 /** Non-NULL if we log to a file. */
40 static FILE *logfile;
41 /** The read end of the signal pipe */
42 static int signal_pipe;
43 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
44 static pid_t create_pid;
45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
46 static int create_process_stopped;
47 /** Process id of current pre-remove/rm/post-remove process. */
48 static pid_t remove_pid;
49 /** When the next snapshot is due. */
50 static int64_t next_snapshot_time;
51 /** When to try to remove something. */
52 static struct timeval next_removal_check;
53 /** Creation time of the snapshot currently being created. */
54 static int64_t current_snapshot_creation_time;
55 /** The snapshot currently being removed. */
56 struct snapshot *snapshot_currently_being_removed;
57 /** Needed by the post-create hook. */
58 static char *path_to_last_complete_snapshot;
59 static char *name_of_reference_snapshot;
60 /** \sa \ref snap.h for details. */
61 enum hook_status snapshot_creation_status;
62 /** \sa \ref snap.h for details. */
63 enum hook_status snapshot_removal_status;
64
65
66 DEFINE_DSS_ERRLIST;
67
68
69 /* a litte cpp magic helps to DRY */
70 #define COMMANDS \
71 COMMAND(ls) \
72 COMMAND(create) \
73 COMMAND(prune) \
74 COMMAND(run)
75 #define COMMAND(x) static int com_ ##x(void);
76 COMMANDS
77 #undef COMMAND
78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
79 static int call_command_handler(void)
80 {
81 COMMANDS
82 DSS_EMERG_LOG("BUG: did not find command handler\n");
83 return -E_BUG;
84 }
85 #undef COMMAND
86 #undef COMMANDS
87
88 /**
89 * The log function of dss.
90 *
91 * \param ll Loglevel.
92 * \param fml Usual format string.
93 *
94 * All DSS_XXX_LOG() macros use this function.
95 */
96 __printf_2_3 void dss_log(int ll, const char* fmt,...)
97 {
98 va_list argp;
99 FILE *outfd;
100 struct tm *tm;
101 time_t t1;
102 char str[255] = "";
103
104 if (ll < conf.loglevel_arg)
105 return;
106 outfd = logfile? logfile : stderr;
107 time(&t1);
108 tm = localtime(&t1);
109 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
110 fprintf(outfd, "%s ", str);
111 if (conf.loglevel_arg <= INFO)
112 fprintf(outfd, "%i: ", ll);
113 va_start(argp, fmt);
114 vfprintf(outfd, fmt, argp);
115 va_end(argp);
116 }
117
118 /**
119 * Print a message either to stdout or to the log file.
120 */
121 static __printf_1_2 void dss_msg(const char* fmt,...)
122 {
123 FILE *outfd = conf.daemon_given? logfile : stdout;
124 va_list argp;
125 va_start(argp, fmt);
126 vfprintf(outfd, fmt, argp);
127 va_end(argp);
128 }
129
130 static int disk_space_low(void)
131 {
132 struct disk_space ds;
133 int ret = get_disk_space(".", &ds);
134
135 if (ret < 0)
136 return ret;
137 if (conf.min_free_mb_arg)
138 if (ds.free_mb < conf.min_free_mb_arg)
139 return 1;
140 if (conf.min_free_percent_arg)
141 if (ds.percent_free < conf.min_free_percent_arg)
142 return 1;
143 if (conf.min_free_percent_inodes_arg)
144 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
145 return 1;
146 return 0;
147 }
148
149 static void dss_get_snapshot_list(struct snapshot_list *sl)
150 {
151 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
152 }
153
154 static int64_t compute_next_snapshot_time(void)
155 {
156 int64_t x = 0, now = get_current_time(), unit_interval
157 = 24 * 3600 * conf.unit_interval_arg, ret;
158 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
159 num_complete_snapshots = 0;
160 int i;
161 struct snapshot *s = NULL;
162 struct snapshot_list sl;
163
164 current_snapshot_creation_time = 0;
165 dss_get_snapshot_list(&sl);
166 FOR_EACH_SNAPSHOT(s, i, &sl) {
167 if (!(s->flags & SS_COMPLETE))
168 continue;
169 num_complete_snapshots++;
170 x += s->completion_time - s->creation_time;
171 }
172 assert(x >= 0);
173
174 ret = now;
175 if (num_complete_snapshots == 0)
176 goto out;
177 x /= num_complete_snapshots; /* avg time to create one snapshot */
178 if (unit_interval < x * wanted) /* oops, no sleep at all */
179 goto out;
180 ret = s->completion_time + unit_interval / wanted - x;
181 out:
182 free_snapshot_list(&sl);
183 return ret;
184 }
185
186 static inline void invalidate_next_snapshot_time(void)
187 {
188 next_snapshot_time = 0;
189 }
190
191 static inline int next_snapshot_time_is_valid(void)
192 {
193 return next_snapshot_time != 0;
194 }
195
196 static int next_snapshot_is_due(void)
197 {
198 int64_t now = get_current_time();
199
200 assert(snapshot_creation_status == HS_READY);
201 if (!next_snapshot_time_is_valid())
202 next_snapshot_time = compute_next_snapshot_time();
203 if (next_snapshot_time <= now) {
204 DSS_DEBUG_LOG("next snapshot: now\n");
205 return 1;
206 }
207 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
208 next_snapshot_time - now);
209 return 0;
210 }
211
212 static int pre_create_hook(void)
213 {
214 int ret, fds[3] = {0, 0, 0};
215
216 assert(snapshot_creation_status == HS_READY);
217 /* make sure that the next snapshot time will be recomputed */
218 invalidate_next_snapshot_time();
219 if (!conf.pre_create_hook_given) {
220 snapshot_creation_status = HS_PRE_SUCCESS;
221 return 0;
222 }
223 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
224 ret = dss_exec_cmdline_pid(&create_pid,
225 conf.pre_create_hook_arg, fds);
226 if (ret < 0)
227 return ret;
228 snapshot_creation_status = HS_PRE_RUNNING;
229 return ret;
230 }
231
232 static int pre_remove_hook(struct snapshot *s, const char *why)
233 {
234 int ret, fds[3] = {0, 0, 0};
235 char *cmd;
236
237 if (!s)
238 return 0;
239 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
240 assert(snapshot_removal_status == HS_READY);
241 assert(remove_pid == 0);
242 assert(!snapshot_currently_being_removed);
243
244 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
245 *snapshot_currently_being_removed = *s;
246 snapshot_currently_being_removed->name = dss_strdup(s->name);
247
248 if (!conf.pre_remove_hook_given) {
249 snapshot_removal_status = HS_PRE_SUCCESS;
250 return 0;
251 }
252 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
253 conf.dest_dir_arg, s->name);
254 DSS_DEBUG_LOG("executing %s\n", cmd);
255 ret = dss_exec_cmdline_pid(&remove_pid,
256 conf.pre_remove_hook_arg, fds);
257 free(cmd);
258 if (ret < 0)
259 return ret;
260 snapshot_removal_status = HS_PRE_RUNNING;
261 return ret;
262 }
263
264 static int exec_rm(void)
265 {
266 struct snapshot *s = snapshot_currently_being_removed;
267 int fds[3] = {0, 0, 0};
268 char *new_name = being_deleted_name(s);
269 char *argv[] = {"rm", "-rf", new_name, NULL};
270 int ret;
271
272 assert(snapshot_removal_status == HS_PRE_SUCCESS);
273 assert(remove_pid == 0);
274
275 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
276 ret = dss_rename(s->name, new_name);
277 if (ret < 0)
278 goto out;
279 ret = dss_exec(&remove_pid, argv[0], argv, fds);
280 if (ret < 0)
281 goto out;
282 snapshot_removal_status = HS_RUNNING;
283 out:
284 free(new_name);
285 return ret;
286 }
287
288 static int snapshot_is_being_created(struct snapshot *s)
289 {
290 return s->creation_time == current_snapshot_creation_time;
291 }
292
293 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
294 {
295 struct snapshot *s;
296 int i;
297
298 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
299 FOR_EACH_SNAPSHOT(s, i, sl) {
300 if (snapshot_is_being_created(s))
301 continue;
302 /*
303 * We know that no rm is currently running, so if s is marked
304 * as being deleted, a previously started rm must have failed.
305 */
306 if (s->flags & SS_BEING_DELETED)
307 return s;
308
309 if (s->flags & SS_COMPLETE) /* good snapshot */
310 continue;
311 /*
312 * This snapshot is incomplete and it is not the snapshot
313 * currently being created. However, we must not remove it if
314 * rsync is about to be restarted. As only the newest snapshot
315 * can be restarted, this snapshot is orphaned if it is not the
316 * newest snapshot or if we are not about to restart rsync.
317 */
318 if (get_newest_snapshot(sl) != s)
319 return s;
320 if (snapshot_creation_status != HS_NEEDS_RESTART)
321 return s;
322 }
323 /* no orphaned snapshots */
324 return NULL;
325 }
326
327 static int is_reference_snapshot(struct snapshot *s)
328 {
329 if (!name_of_reference_snapshot)
330 return 0;
331 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
332 }
333
334 /*
335 * return: 0: no redundant snapshots, 1: rm process started, negative: error
336 */
337 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
338 {
339 int i, interval;
340 struct snapshot *s;
341 unsigned missing = 0;
342
343 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
344 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
345 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
346 unsigned num = sl->interval_count[interval];
347 struct snapshot *victim = NULL, *prev = NULL;
348 int64_t score = LONG_MAX;
349
350 if (keep >= num)
351 missing += keep - num;
352 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
353 // interval, keep, num, missing);
354 if (keep + missing >= num)
355 continue;
356 /* redundant snapshot in this interval, pick snapshot with lowest score */
357 FOR_EACH_SNAPSHOT(s, i, sl) {
358 int64_t this_score;
359
360 if (snapshot_is_being_created(s))
361 continue;
362 if (is_reference_snapshot(s))
363 continue;
364 //DSS_DEBUG_LOG("checking %s\n", s->name);
365 if (s->interval > interval) {
366 prev = s;
367 continue;
368 }
369 if (s->interval < interval)
370 break;
371 if (!victim) {
372 victim = s;
373 prev = s;
374 continue;
375 }
376 assert(prev);
377 /* check if s is a better victim */
378 this_score = s->creation_time - prev->creation_time;
379 assert(this_score >= 0);
380 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
381 if (this_score < score) {
382 score = this_score;
383 victim = s;
384 }
385 prev = s;
386 }
387 assert(victim);
388 return victim;
389 }
390 return NULL;
391 }
392
393 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
394 {
395 int i;
396 struct snapshot *s;
397
398 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
399 conf.num_intervals_arg);
400 FOR_EACH_SNAPSHOT(s, i, sl) {
401 if (snapshot_is_being_created(s))
402 continue;
403 if (is_reference_snapshot(s))
404 continue;
405 if (s->interval < conf.num_intervals_arg)
406 continue;
407 return s;
408 }
409 return NULL;
410 }
411
412 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
413 {
414 int i;
415 struct snapshot *s;
416 FOR_EACH_SNAPSHOT(s, i, sl) {
417 if (snapshot_is_being_created(s))
418 continue;
419 if (is_reference_snapshot(s))
420 continue;
421 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
422 return s;
423 }
424 return NULL;
425 }
426
427 static int rename_incomplete_snapshot(int64_t start)
428 {
429 char *old_name;
430 int ret;
431
432 free(path_to_last_complete_snapshot);
433 ret = complete_name(start, get_current_time(),
434 &path_to_last_complete_snapshot);
435 if (ret < 0)
436 return ret;
437 old_name = incomplete_name(start);
438 ret = dss_rename(old_name, path_to_last_complete_snapshot);
439 if (ret >= 0)
440 DSS_NOTICE_LOG("%s -> %s\n", old_name,
441 path_to_last_complete_snapshot);
442 free(old_name);
443 return ret;
444 }
445
446 static int try_to_free_disk_space(void)
447 {
448 int ret;
449 struct snapshot_list sl;
450 struct snapshot *victim;
451 struct timeval now;
452 const char *why;
453 int low_disk_space;
454
455 ret = disk_space_low();
456 if (ret < 0)
457 return ret;
458 low_disk_space = ret;
459 gettimeofday(&now, NULL);
460 if (tv_diff(&next_removal_check, &now, NULL) > 0)
461 return 0;
462 if (!low_disk_space) {
463 if (conf.keep_redundant_given)
464 return 0;
465 if (snapshot_creation_status != HS_READY)
466 return 0;
467 if (next_snapshot_is_due())
468 return 0;
469 }
470 dss_get_snapshot_list(&sl);
471 ret = 0;
472 if (!low_disk_space && sl.num_snapshots <= 1)
473 goto out;
474 why = "outdated";
475 victim = find_outdated_snapshot(&sl);
476 if (victim)
477 goto remove;
478 why = "redundant";
479 victim = find_redundant_snapshot(&sl);
480 if (victim)
481 goto remove;
482 /* try harder only if disk space is low */
483 if (!low_disk_space)
484 goto out;
485 why = "orphaned";
486 victim = find_orphaned_snapshot(&sl);
487 if (victim)
488 goto remove;
489 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
490 victim = find_oldest_removable_snapshot(&sl);
491 if (victim)
492 goto remove;
493 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
494 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
495 goto out;
496 remove:
497 ret = pre_remove_hook(victim, why);
498 out:
499 free_snapshot_list(&sl);
500 return ret;
501 }
502
503 static int post_create_hook(void)
504 {
505 int ret, fds[3] = {0, 0, 0};
506 char *cmd;
507
508 if (!conf.post_create_hook_given) {
509 snapshot_creation_status = HS_READY;
510 return 0;
511 }
512 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
513 conf.dest_dir_arg, path_to_last_complete_snapshot);
514 DSS_NOTICE_LOG("executing %s\n", cmd);
515 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
516 free(cmd);
517 if (ret < 0)
518 return ret;
519 snapshot_creation_status = HS_POST_RUNNING;
520 return ret;
521 }
522
523 static int post_remove_hook(void)
524 {
525 int ret, fds[3] = {0, 0, 0};
526 char *cmd;
527 struct snapshot *s = snapshot_currently_being_removed;
528
529 assert(s);
530
531 if (!conf.post_remove_hook_given) {
532 snapshot_removal_status = HS_READY;
533 return 0;
534 }
535 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
536 conf.dest_dir_arg, s->name);
537 DSS_NOTICE_LOG("executing %s\n", cmd);
538 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
539 free(cmd);
540 if (ret < 0)
541 return ret;
542 snapshot_removal_status = HS_POST_RUNNING;
543 return ret;
544 }
545
546 static void kill_process(pid_t pid)
547 {
548 if (!pid)
549 return;
550 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
551 kill(pid, SIGTERM);
552 }
553
554 static void stop_create_process(void)
555 {
556 if (!create_pid || create_process_stopped)
557 return;
558 kill(SIGSTOP, create_pid);
559 create_process_stopped = 1;
560 }
561
562 static void restart_create_process(void)
563 {
564 if (!create_pid || !create_process_stopped)
565 return;
566 kill (SIGCONT, create_pid);
567 create_process_stopped = 0;
568 }
569
570 /**
571 * Print a log message about the exit status of a child.
572 */
573 static void log_termination_msg(pid_t pid, int status)
574 {
575 if (WIFEXITED(status))
576 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
577 WEXITSTATUS(status));
578 else if (WIFSIGNALED(status))
579 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
580 WTERMSIG(status));
581 else
582 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
583 }
584
585 static int wait_for_process(pid_t pid, int *status)
586 {
587 int ret;
588
589 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
590 for (;;) {
591 fd_set rfds;
592
593 FD_ZERO(&rfds);
594 FD_SET(signal_pipe, &rfds);
595 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
596 if (ret < 0)
597 break;
598 ret = next_signal();
599 if (!ret)
600 continue;
601 if (ret == SIGCHLD) {
602 ret = waitpid(pid, status, 0);
603 if (ret >= 0)
604 break;
605 if (errno != EINTR) { /* error */
606 ret = -ERRNO_TO_DSS_ERROR(errno);
607 break;
608 }
609 }
610 /* SIGINT or SIGTERM */
611 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
612 kill(pid, SIGTERM);
613 }
614 if (ret < 0)
615 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
616 else
617 log_termination_msg(pid, *status);
618 return ret;
619 }
620
621 static void handle_pre_remove_exit(int status)
622 {
623 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
624 snapshot_removal_status = HS_READY;
625 gettimeofday(&next_removal_check, NULL);
626 next_removal_check.tv_sec += 60;
627 return;
628 }
629 snapshot_removal_status = HS_PRE_SUCCESS;
630 }
631
632 static int handle_rm_exit(int status)
633 {
634 if (!WIFEXITED(status)) {
635 snapshot_removal_status = HS_READY;
636 return -E_INVOLUNTARY_EXIT;
637 }
638 if (WEXITSTATUS(status)) {
639 snapshot_removal_status = HS_READY;
640 return -E_BAD_EXIT_CODE;
641 }
642 if (conf.post_remove_hook_given)
643 snapshot_removal_status = HS_SUCCESS;
644 else
645 snapshot_removal_status = HS_READY;
646 return 1;
647 }
648
649 static void handle_post_remove_exit(void)
650 {
651 snapshot_removal_status = HS_READY;
652 }
653
654 static int handle_remove_exit(int status)
655 {
656 int ret;
657 struct snapshot *s = snapshot_currently_being_removed;
658
659 assert(s);
660 switch (snapshot_removal_status) {
661 case HS_PRE_RUNNING:
662 handle_pre_remove_exit(status);
663 ret = 1;
664 break;
665 case HS_RUNNING:
666 ret = handle_rm_exit(status);
667 break;
668 case HS_POST_RUNNING:
669 handle_post_remove_exit();
670 ret = 1;
671 break;
672 default:
673 ret = -E_BUG;
674 }
675 if (snapshot_removal_status == HS_READY) {
676 free(s->name);
677 free(s);
678 snapshot_currently_being_removed = NULL;
679 }
680 remove_pid = 0;
681 return ret;
682 }
683
684 static int wait_for_remove_process(void)
685 {
686 int status, ret;
687
688 assert(remove_pid);
689 assert(
690 snapshot_removal_status == HS_PRE_RUNNING ||
691 snapshot_removal_status == HS_RUNNING ||
692 snapshot_removal_status == HS_POST_RUNNING
693 );
694 ret = wait_for_process(remove_pid, &status);
695 if (ret < 0)
696 return ret;
697 return handle_remove_exit(status);
698 }
699
700 static int handle_rsync_exit(int status)
701 {
702 int es, ret;
703
704 if (!WIFEXITED(status)) {
705 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
706 ret = -E_INVOLUNTARY_EXIT;
707 snapshot_creation_status = HS_READY;
708 goto out;
709 }
710 es = WEXITSTATUS(status);
711 /*
712 * Restart rsync on non-fatal errors:
713 * 12: Error in rsync protocol data stream
714 * 13: Errors with program diagnostics
715 */
716 if (es == 12 || es == 13) {
717 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
718 (int)create_pid, es);
719 snapshot_creation_status = HS_NEEDS_RESTART;
720 next_snapshot_time = get_current_time() + 60;
721 ret = 1;
722 goto out;
723 }
724 if (es != 0 && es != 23 && es != 24) {
725 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
726 ret = -E_BAD_EXIT_CODE;
727 snapshot_creation_status = HS_READY;
728 goto out;
729 }
730 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
731 if (ret < 0)
732 goto out;
733 snapshot_creation_status = HS_SUCCESS;
734 free(name_of_reference_snapshot);
735 name_of_reference_snapshot = NULL;
736 out:
737 create_process_stopped = 0;
738 return ret;
739 }
740
741 static int handle_pre_create_hook_exit(int status)
742 {
743 int es, ret;
744 static int warn_count;
745
746 if (!WIFEXITED(status)) {
747 snapshot_creation_status = HS_READY;
748 ret = -E_INVOLUNTARY_EXIT;
749 goto out;
750 }
751 es = WEXITSTATUS(status);
752 if (es) {
753 if (!warn_count--) {
754 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
755 conf.pre_create_hook_arg, es);
756 DSS_NOTICE_LOG("deferring snapshot creation...\n");
757 warn_count = 60; /* warn only once per hour */
758 }
759 next_snapshot_time = get_current_time() + 60;
760 snapshot_creation_status = HS_READY;
761 ret = 0;
762 goto out;
763 }
764 warn_count = 0;
765 snapshot_creation_status = HS_PRE_SUCCESS;
766 ret = 1;
767 out:
768 return ret;
769 }
770
771 static int handle_sigchld(void)
772 {
773 pid_t pid;
774 int status, ret = reap_child(&pid, &status);
775
776 if (ret <= 0)
777 return ret;
778
779 if (pid == create_pid) {
780 switch (snapshot_creation_status) {
781 case HS_PRE_RUNNING:
782 return handle_pre_create_hook_exit(status);
783 case HS_RUNNING:
784 return handle_rsync_exit(status);
785 case HS_POST_RUNNING:
786 snapshot_creation_status = HS_READY;
787 return 1;
788 default:
789 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
790 snapshot_creation_status);
791 return -E_BUG;
792 }
793 create_pid = 0;
794 }
795 if (pid == remove_pid) {
796 ret = handle_remove_exit(status);
797 if (ret < 0)
798 return ret;
799 return ret;
800 }
801 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
802 return -E_BUG;
803 }
804
805 static int check_config(void)
806 {
807 if (conf.unit_interval_arg <= 0) {
808 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
809 return -E_INVALID_NUMBER;
810 }
811 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
812 if (conf.num_intervals_arg <= 0) {
813 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
814 return -E_INVALID_NUMBER;
815 }
816 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
817 return 1;
818 }
819
820 /*
821 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
822 * file was read successfully.
823 */
824 static int parse_config_file(int override)
825 {
826 int ret, config_file_exists;
827 char *config_file;
828 struct stat statbuf;
829 char *old_logfile_arg = NULL;
830 int old_daemon_given = 0;
831
832 if (conf.config_file_given)
833 config_file = dss_strdup(conf.config_file_arg);
834 else {
835 char *home = get_homedir();
836 config_file = make_message("%s/.dssrc", home);
837 free(home);
838 }
839 if (override) { /* SIGHUP */
840 if (conf.logfile_given)
841 old_logfile_arg = dss_strdup(conf.logfile_arg);
842 old_daemon_given = conf.daemon_given;
843 }
844
845 config_file_exists = !stat(config_file, &statbuf);
846 if (!config_file_exists && conf.config_file_given) {
847 ret = -ERRNO_TO_DSS_ERROR(errno);
848 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
849 goto out;
850 }
851 if (config_file_exists) {
852 struct cmdline_parser_params params = {
853 .override = override,
854 .initialize = 0,
855 .check_required = 1,
856 .check_ambiguity = 0,
857 .print_errors = 1
858 };
859 if (override) { /* invalidate all rsync options */
860 int i;
861
862 for (i = 0; i < conf.rsync_option_given; i++) {
863 free(conf.rsync_option_arg[i]);
864 conf.rsync_option_arg[i] = NULL;
865 }
866 conf.rsync_option_given = 0;
867 }
868 cmdline_parser_config_file(config_file, &conf, &params);
869 }
870 ret = check_config();
871 if (ret < 0)
872 goto out;
873 if (override) {
874 /* don't change daemon mode on SIGHUP */
875 conf.daemon_given = old_daemon_given;
876 close_log(logfile);
877 logfile = NULL;
878 if (conf.logfile_given)
879 free(old_logfile_arg);
880 else if (conf.daemon_given) { /* re-use old logfile */
881 conf.logfile_arg = old_logfile_arg;
882 conf.logfile_given = 1;
883 }
884 }
885 if (conf.logfile_given) {
886 logfile = open_log(conf.logfile_arg);
887 log_welcome(conf.loglevel_arg);
888 }
889 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
890 ret = config_file_exists;
891 out:
892 free(config_file);
893 if (ret < 0)
894 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
895 return ret;
896 }
897
898 static int change_to_dest_dir(void)
899 {
900 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
901 return dss_chdir(conf.dest_dir_arg);
902 }
903
904 static void dump_dss_config(const char *msg)
905 {
906 if (conf.loglevel_arg > INFO)
907 return;
908 DSS_INFO_LOG("%s\n", msg);
909 cmdline_parser_dump(logfile? logfile : stderr, &conf);
910 }
911
912 static int handle_sighup(void)
913 {
914 int ret;
915
916 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
917 dump_dss_config("current config");
918 ret = parse_config_file(1);
919 if (ret < 0)
920 return ret;
921 dump_dss_config("new config");
922 invalidate_next_snapshot_time();
923 return change_to_dest_dir();
924 }
925
926 static int handle_signal(void)
927 {
928 int sig, ret = next_signal();
929
930 if (ret <= 0)
931 goto out;
932 sig = ret;
933 switch (sig) {
934 case SIGINT:
935 case SIGTERM:
936 restart_create_process();
937 kill_process(create_pid);
938 kill_process(remove_pid);
939 ret = -E_SIGNAL;
940 break;
941 case SIGHUP:
942 ret = handle_sighup();
943 break;
944 case SIGCHLD:
945 ret = handle_sigchld();
946 break;
947 }
948 out:
949 if (ret < 0)
950 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
951 return ret;
952 }
953
954 /*
955 * We can not use rsync locally if the local user is different from the remote
956 * user or if the src dir is not on the local host (or both).
957 */
958 static int use_rsync_locally(char *logname)
959 {
960 char *h = conf.remote_host_arg;
961
962 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
963 return 0;
964 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
965 return 0;
966 return 1;
967 }
968
969 static void create_rsync_argv(char ***argv, int64_t *num)
970 {
971 char *logname;
972 int i = 0, j;
973 struct snapshot_list sl;
974
975 dss_get_snapshot_list(&sl);
976 assert(!name_of_reference_snapshot);
977 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
978 free_snapshot_list(&sl);
979
980 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
981 (*argv)[i++] = dss_strdup("rsync");
982 (*argv)[i++] = dss_strdup("-aq");
983 (*argv)[i++] = dss_strdup("--delete");
984 for (j = 0; j < conf.rsync_option_given; j++)
985 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
986 if (name_of_reference_snapshot) {
987 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
988 (*argv)[i++] = make_message("--link-dest=../%s",
989 name_of_reference_snapshot);
990 } else
991 DSS_INFO_LOG("no suitable reference snapshot found\n");
992 logname = dss_logname();
993 if (use_rsync_locally(logname))
994 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
995 else
996 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
997 conf.remote_user_arg : logname,
998 conf.remote_host_arg, conf.source_dir_arg);
999 free(logname);
1000 *num = get_current_time();
1001 (*argv)[i++] = incomplete_name(*num);
1002 (*argv)[i++] = NULL;
1003 for (j = 0; j < i; j++)
1004 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1005 }
1006
1007 static void free_rsync_argv(char **argv)
1008 {
1009 int i;
1010
1011 if (!argv)
1012 return;
1013 for (i = 0; argv[i]; i++)
1014 free(argv[i]);
1015 free(argv);
1016 }
1017
1018 static int create_snapshot(char **argv)
1019 {
1020 int ret, fds[3] = {0, 0, 0};
1021 char *name;
1022
1023 name = incomplete_name(current_snapshot_creation_time);
1024 DSS_NOTICE_LOG("creating new snapshot %s\n", name);
1025 free(name);
1026 ret = dss_exec(&create_pid, argv[0], argv, fds);
1027 if (ret < 0)
1028 return ret;
1029 snapshot_creation_status = HS_RUNNING;
1030 return ret;
1031 }
1032
1033 static int select_loop(void)
1034 {
1035 int ret;
1036 /* check every 60 seconds for free disk space */
1037 struct timeval tv;
1038 char **rsync_argv = NULL;
1039
1040 for (;;) {
1041 fd_set rfds;
1042 struct timeval *tvp;
1043
1044 if (remove_pid)
1045 tvp = NULL; /* sleep until rm hook/process dies */
1046 else { /* sleep one minute */
1047 tv.tv_sec = 60;
1048 tv.tv_usec = 0;
1049 tvp = &tv;
1050 }
1051 FD_ZERO(&rfds);
1052 FD_SET(signal_pipe, &rfds);
1053 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1054 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1055 if (ret < 0)
1056 goto out;
1057 if (FD_ISSET(signal_pipe, &rfds)) {
1058 ret = handle_signal();
1059 if (ret < 0)
1060 goto out;
1061 }
1062 if (remove_pid)
1063 continue;
1064 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1065 ret = exec_rm();
1066 if (ret < 0)
1067 goto out;
1068 continue;
1069 }
1070 if (snapshot_removal_status == HS_SUCCESS) {
1071 ret = post_remove_hook();
1072 if (ret < 0)
1073 goto out;
1074 continue;
1075 }
1076 ret = try_to_free_disk_space();
1077 if (ret < 0)
1078 goto out;
1079 if (snapshot_removal_status != HS_READY) {
1080 stop_create_process();
1081 continue;
1082 }
1083 restart_create_process();
1084 switch (snapshot_creation_status) {
1085 case HS_READY:
1086 if (!next_snapshot_is_due())
1087 continue;
1088 ret = pre_create_hook();
1089 if (ret < 0)
1090 goto out;
1091 continue;
1092 case HS_PRE_RUNNING:
1093 case HS_RUNNING:
1094 case HS_POST_RUNNING:
1095 continue;
1096 case HS_PRE_SUCCESS:
1097 free_rsync_argv(rsync_argv);
1098 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1099 /* fall through */
1100 case HS_NEEDS_RESTART:
1101 ret = create_snapshot(rsync_argv);
1102 if (ret < 0)
1103 goto out;
1104 continue;
1105 case HS_SUCCESS:
1106 ret = post_create_hook();
1107 if (ret < 0)
1108 goto out;
1109 continue;
1110 }
1111 }
1112 out:
1113 return ret;
1114 }
1115
1116 static void exit_hook(int exit_code)
1117 {
1118 int fds[3] = {0, 0, 0};
1119 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1120 pid_t pid;
1121
1122 if (!conf.exit_hook_given)
1123 return;
1124 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1125 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1126 }
1127
1128 static int com_run(void)
1129 {
1130 int ret;
1131
1132 if (conf.dry_run_given) {
1133 DSS_ERROR_LOG("dry_run not supported by this command\n");
1134 return -E_SYNTAX;
1135 }
1136 ret = install_sighandler(SIGHUP);
1137 if (ret < 0)
1138 return ret;
1139 ret = select_loop();
1140 if (ret >= 0) /* impossible */
1141 ret = -E_BUG;
1142 exit_hook(ret);
1143 return ret;
1144 }
1145
1146 static int com_prune(void)
1147 {
1148 int ret;
1149 struct snapshot_list sl;
1150 struct snapshot *victim;
1151 struct disk_space ds;
1152 const char *why;
1153
1154 ret = get_disk_space(".", &ds);
1155 if (ret < 0)
1156 return ret;
1157 log_disk_space(&ds);
1158 dss_get_snapshot_list(&sl);
1159 why = "outdated";
1160 victim = find_outdated_snapshot(&sl);
1161 if (victim)
1162 goto rm;
1163 why = "redundant";
1164 victim = find_redundant_snapshot(&sl);
1165 if (victim)
1166 goto rm;
1167 ret = 0;
1168 goto out;
1169 rm:
1170 if (conf.dry_run_given) {
1171 dss_msg("%s snapshot %s (interval = %i)\n",
1172 why, victim->name, victim->interval);
1173 ret = 0;
1174 goto out;
1175 }
1176 ret = pre_remove_hook(victim, why);
1177 if (ret < 0)
1178 goto out;
1179 if (snapshot_removal_status == HS_PRE_RUNNING) {
1180 ret = wait_for_remove_process();
1181 if (ret < 0)
1182 goto out;
1183 if (snapshot_removal_status != HS_PRE_SUCCESS)
1184 goto out;
1185 }
1186 ret = exec_rm();
1187 if (ret < 0)
1188 goto out;
1189 ret = wait_for_remove_process();
1190 if (ret < 0)
1191 goto out;
1192 if (snapshot_removal_status != HS_SUCCESS)
1193 goto out;
1194 ret = post_remove_hook();
1195 if (ret < 0)
1196 goto out;
1197 if (snapshot_removal_status != HS_POST_RUNNING)
1198 goto out;
1199 ret = wait_for_remove_process();
1200 if (ret < 0)
1201 goto out;
1202 ret = 1;
1203 out:
1204 free_snapshot_list(&sl);
1205 return ret;
1206 }
1207
1208 static int com_create(void)
1209 {
1210 int ret, status;
1211 char **rsync_argv;
1212
1213 if (conf.dry_run_given) {
1214 int i;
1215 char *msg = NULL;
1216 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1217 for (i = 0; rsync_argv[i]; i++) {
1218 char *tmp = msg;
1219 msg = make_message("%s%s%s", tmp? tmp : "",
1220 tmp? " " : "", rsync_argv[i]);
1221 free(tmp);
1222 }
1223 free_rsync_argv(rsync_argv);
1224 dss_msg("%s\n", msg);
1225 free(msg);
1226 return 1;
1227 }
1228 ret = pre_create_hook();
1229 if (ret < 0)
1230 return ret;
1231 if (create_pid) {
1232 ret = wait_for_process(create_pid, &status);
1233 if (ret < 0)
1234 return ret;
1235 ret = handle_pre_create_hook_exit(status);
1236 if (ret <= 0) /* error, or pre-create failed */
1237 return ret;
1238 }
1239 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1240 ret = create_snapshot(rsync_argv);
1241 if (ret < 0)
1242 goto out;
1243 ret = wait_for_process(create_pid, &status);
1244 if (ret < 0)
1245 goto out;
1246 ret = handle_rsync_exit(status);
1247 if (ret < 0)
1248 goto out;
1249 post_create_hook();
1250 if (create_pid)
1251 ret = wait_for_process(create_pid, &status);
1252 out:
1253 free_rsync_argv(rsync_argv);
1254 return ret;
1255 }
1256
1257 static int com_ls(void)
1258 {
1259 int i;
1260 struct snapshot_list sl;
1261 struct snapshot *s;
1262
1263 dss_get_snapshot_list(&sl);
1264 FOR_EACH_SNAPSHOT(s, i, &sl) {
1265 int64_t d = 0;
1266 if (s->flags & SS_COMPLETE)
1267 d = (s->completion_time - s->creation_time) / 60;
1268 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1269 };
1270 free_snapshot_list(&sl);
1271 return 1;
1272 }
1273
1274 static int setup_signal_handling(void)
1275 {
1276 int ret;
1277
1278 DSS_INFO_LOG("setting up signal handlers\n");
1279 signal_pipe = signal_init(); /* always successful */
1280 ret = install_sighandler(SIGINT);
1281 if (ret < 0)
1282 return ret;
1283 ret = install_sighandler(SIGTERM);
1284 if (ret < 0)
1285 return ret;
1286 return install_sighandler(SIGCHLD);
1287 }
1288
1289 /**
1290 * The main function of dss.
1291 *
1292 * \param argc Usual argument count.
1293 * \param argv Usual argument vector.
1294 */
1295 int main(int argc, char **argv)
1296 {
1297 int ret;
1298 struct cmdline_parser_params params = {
1299 .override = 0,
1300 .initialize = 1,
1301 .check_required = 0,
1302 .check_ambiguity = 0,
1303 .print_errors = 1
1304 };
1305
1306 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1307 ret = parse_config_file(0);
1308 if (ret < 0)
1309 goto out;
1310 if (ret == 0) { /* no config file given */
1311 /*
1312 * Parse the command line options again, but this time check
1313 * that all required options are given.
1314 */
1315 params = (struct cmdline_parser_params) {
1316 .override = 1,
1317 .initialize = 1,
1318 .check_required = 1,
1319 .check_ambiguity = 1,
1320 .print_errors = 1
1321 };
1322 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1323 }
1324 if (conf.daemon_given)
1325 daemon_init();
1326 dump_dss_config("dss configuration");
1327 ret = change_to_dest_dir();
1328 if (ret < 0)
1329 goto out;
1330 ret = setup_signal_handling();
1331 if (ret < 0)
1332 goto out;
1333 ret = call_command_handler();
1334 out:
1335 if (ret < 0)
1336 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1337 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1338 }