Use logfile only for --run --daemon.
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6 #include <string.h>
7 #include <stdlib.h>
8 #include <stdarg.h>
9 #include <assert.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <signal.h>
13 #include <ctype.h>
14 #include <sys/stat.h>
15 #include <unistd.h>
16 #include <inttypes.h>
17 #include <sys/time.h>
18 #include <time.h>
19 #include <sys/wait.h>
20 #include <fnmatch.h>
21 #include <limits.h>
22
23
24 #include "gcc-compat.h"
25 #include "cmdline.h"
26 #include "log.h"
27 #include "string.h"
28 #include "error.h"
29 #include "fd.h"
30 #include "exec.h"
31 #include "daemon.h"
32 #include "signal.h"
33 #include "df.h"
34 #include "time.h"
35 #include "snap.h"
36
37 /** Command line and config file options. */
38 static struct gengetopt_args_info conf;
39 /** Non-NULL if we log to a file. */
40 static FILE *logfile;
41 /** The read end of the signal pipe */
42 static int signal_pipe;
43 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
44 static pid_t create_pid;
45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
46 static int create_process_stopped;
47 /** Process id of current pre-remove/rm/post-remove process. */
48 static pid_t remove_pid;
49 /** When the next snapshot is due. */
50 static int64_t next_snapshot_time;
51 /** When to try to remove something. */
52 static struct timeval next_removal_check;
53 /** Creation time of the snapshot currently being created. */
54 static int64_t current_snapshot_creation_time;
55 /** The snapshot currently being removed. */
56 struct snapshot *snapshot_currently_being_removed;
57 /** Needed by the post-create hook. */
58 static char *path_to_last_complete_snapshot;
59 static char *name_of_reference_snapshot;
60 /** \sa \ref snap.h for details. */
61 enum hook_status snapshot_creation_status;
62 /** \sa \ref snap.h for details. */
63 enum hook_status snapshot_removal_status;
64
65
66 DEFINE_DSS_ERRLIST;
67
68
69 /* a litte cpp magic helps to DRY */
70 #define COMMANDS \
71 COMMAND(ls) \
72 COMMAND(create) \
73 COMMAND(prune) \
74 COMMAND(run)
75 #define COMMAND(x) static int com_ ##x(void);
76 COMMANDS
77 #undef COMMAND
78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
79 static int call_command_handler(void)
80 {
81 COMMANDS
82 DSS_EMERG_LOG("BUG: did not find command handler\n");
83 return -E_BUG;
84 }
85 #undef COMMAND
86 #undef COMMANDS
87
88 /**
89 * The log function of dss.
90 *
91 * \param ll Loglevel.
92 * \param fml Usual format string.
93 *
94 * All DSS_XXX_LOG() macros use this function.
95 */
96 __printf_2_3 void dss_log(int ll, const char* fmt,...)
97 {
98 va_list argp;
99 FILE *outfd;
100 struct tm *tm;
101 time_t t1;
102 char str[255] = "";
103
104 if (ll < conf.loglevel_arg)
105 return;
106 outfd = logfile? logfile : stderr;
107 time(&t1);
108 tm = localtime(&t1);
109 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
110 fprintf(outfd, "%s ", str);
111 if (conf.loglevel_arg <= INFO)
112 fprintf(outfd, "%i: ", ll);
113 va_start(argp, fmt);
114 vfprintf(outfd, fmt, argp);
115 va_end(argp);
116 }
117
118 /**
119 * Print a message either to stdout or to the log file.
120 */
121 static __printf_1_2 void dss_msg(const char* fmt,...)
122 {
123 FILE *outfd = conf.daemon_given? logfile : stdout;
124 va_list argp;
125 va_start(argp, fmt);
126 vfprintf(outfd, fmt, argp);
127 va_end(argp);
128 }
129
130 static int disk_space_low(void)
131 {
132 struct disk_space ds;
133 int ret = get_disk_space(".", &ds);
134
135 if (ret < 0)
136 return ret;
137 if (conf.min_free_mb_arg)
138 if (ds.free_mb < conf.min_free_mb_arg)
139 return 1;
140 if (conf.min_free_percent_arg)
141 if (ds.percent_free < conf.min_free_percent_arg)
142 return 1;
143 if (conf.min_free_percent_inodes_arg)
144 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
145 return 1;
146 return 0;
147 }
148
149 static void dss_get_snapshot_list(struct snapshot_list *sl)
150 {
151 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
152 }
153
154 static int64_t compute_next_snapshot_time(void)
155 {
156 int64_t x = 0, now = get_current_time(), unit_interval
157 = 24 * 3600 * conf.unit_interval_arg, ret;
158 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
159 num_complete_snapshots = 0;
160 int i;
161 struct snapshot *s = NULL;
162 struct snapshot_list sl;
163
164 dss_get_snapshot_list(&sl);
165 FOR_EACH_SNAPSHOT(s, i, &sl) {
166 if (!(s->flags & SS_COMPLETE))
167 continue;
168 num_complete_snapshots++;
169 x += s->completion_time - s->creation_time;
170 }
171 assert(x >= 0);
172
173 ret = now;
174 if (num_complete_snapshots == 0)
175 goto out;
176 x /= num_complete_snapshots; /* avg time to create one snapshot */
177 if (unit_interval < x * wanted) /* oops, no sleep at all */
178 goto out;
179 ret = s->completion_time + unit_interval / wanted - x;
180 out:
181 free_snapshot_list(&sl);
182 return ret;
183 }
184
185 static inline void invalidate_next_snapshot_time(void)
186 {
187 next_snapshot_time = 0;
188 }
189
190 static inline int next_snapshot_time_is_valid(void)
191 {
192 return next_snapshot_time != 0;
193 }
194
195 static int next_snapshot_is_due(void)
196 {
197 int64_t now = get_current_time();
198
199 if (!next_snapshot_time_is_valid())
200 next_snapshot_time = compute_next_snapshot_time();
201 if (next_snapshot_time <= now) {
202 DSS_DEBUG_LOG("next snapshot: now\n");
203 return 1;
204 }
205 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
206 next_snapshot_time - now);
207 return 0;
208 }
209
210 static int pre_create_hook(void)
211 {
212 int ret, fds[3] = {0, 0, 0};
213
214 assert(snapshot_creation_status == HS_READY);
215 /* make sure that the next snapshot time will be recomputed */
216 invalidate_next_snapshot_time();
217 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
218 ret = dss_exec_cmdline_pid(&create_pid,
219 conf.pre_create_hook_arg, fds);
220 if (ret < 0)
221 return ret;
222 snapshot_creation_status = HS_PRE_RUNNING;
223 return ret;
224 }
225
226 static int pre_remove_hook(struct snapshot *s, const char *why)
227 {
228 int ret, fds[3] = {0, 0, 0};
229 char *cmd;
230
231 if (!s)
232 return 0;
233 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
234 assert(snapshot_removal_status == HS_READY);
235 assert(remove_pid == 0);
236 assert(!snapshot_currently_being_removed);
237
238 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
239 *snapshot_currently_being_removed = *s;
240 snapshot_currently_being_removed->name = dss_strdup(s->name);
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, cmd, fds);
246 free(cmd);
247 if (ret < 0)
248 return ret;
249 snapshot_removal_status = HS_PRE_RUNNING;
250 return ret;
251 }
252
253 static int exec_rm(void)
254 {
255 struct snapshot *s = snapshot_currently_being_removed;
256 int fds[3] = {0, 0, 0};
257 char *new_name = being_deleted_name(s);
258 char *argv[] = {"rm", "-rf", new_name, NULL};
259 int ret;
260
261 assert(snapshot_removal_status == HS_PRE_SUCCESS);
262 assert(remove_pid == 0);
263
264 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
265 ret = dss_rename(s->name, new_name);
266 if (ret < 0)
267 goto out;
268 ret = dss_exec(&remove_pid, argv[0], argv, fds);
269 if (ret < 0)
270 goto out;
271 snapshot_removal_status = HS_RUNNING;
272 out:
273 free(new_name);
274 return ret;
275 }
276
277 static int snapshot_is_being_created(struct snapshot *s)
278 {
279 return s->creation_time == current_snapshot_creation_time;
280 }
281
282 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
283 {
284 struct snapshot *s;
285 int i;
286
287 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
288 FOR_EACH_SNAPSHOT(s, i, sl) {
289 if (snapshot_is_being_created(s))
290 continue;
291 /*
292 * We know that no rm is currently running, so if s is marked
293 * as being deleted, a previously started rm must have failed.
294 */
295 if (s->flags & SS_BEING_DELETED)
296 return s;
297
298 if (s->flags & SS_COMPLETE) /* good snapshot */
299 continue;
300 /*
301 * This snapshot is incomplete and it is not the snapshot
302 * currently being created. However, we must not remove it if
303 * rsync is about to be restarted. As only the newest snapshot
304 * can be restarted, this snapshot is orphaned if it is not the
305 * newest snapshot or if we are not about to restart rsync.
306 */
307 if (get_newest_snapshot(sl) != s)
308 return s;
309 if (snapshot_creation_status != HS_NEEDS_RESTART)
310 return s;
311 }
312 /* no orphaned snapshots */
313 return NULL;
314 }
315
316 static int is_reference_snapshot(struct snapshot *s)
317 {
318 if (!name_of_reference_snapshot)
319 return 0;
320 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
321 }
322
323 /*
324 * return: 0: no redundant snapshots, 1: rm process started, negative: error
325 */
326 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
327 {
328 int i, interval;
329 struct snapshot *s;
330 unsigned missing = 0;
331
332 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
333 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
334 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
335 unsigned num = sl->interval_count[interval];
336 struct snapshot *victim = NULL, *prev = NULL;
337 int64_t score = LONG_MAX;
338
339 if (keep >= num)
340 missing += keep - num;
341 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
342 // interval, keep, num, missing);
343 if (keep + missing >= num)
344 continue;
345 /* redundant snapshot in this interval, pick snapshot with lowest score */
346 FOR_EACH_SNAPSHOT(s, i, sl) {
347 int64_t this_score;
348
349 if (snapshot_is_being_created(s))
350 continue;
351 if (is_reference_snapshot(s))
352 continue;
353 //DSS_DEBUG_LOG("checking %s\n", s->name);
354 if (s->interval > interval) {
355 prev = s;
356 continue;
357 }
358 if (s->interval < interval)
359 break;
360 if (!victim) {
361 victim = s;
362 prev = s;
363 continue;
364 }
365 assert(prev);
366 /* check if s is a better victim */
367 this_score = s->creation_time - prev->creation_time;
368 assert(this_score >= 0);
369 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
370 if (this_score < score) {
371 score = this_score;
372 victim = s;
373 }
374 prev = s;
375 }
376 assert(victim);
377 return victim;
378 }
379 return NULL;
380 }
381
382 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
383 {
384 int i;
385 struct snapshot *s;
386
387 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
388 conf.num_intervals_arg);
389 FOR_EACH_SNAPSHOT(s, i, sl) {
390 if (snapshot_is_being_created(s))
391 continue;
392 if (is_reference_snapshot(s))
393 continue;
394 if (s->interval < conf.num_intervals_arg)
395 continue;
396 return s;
397 }
398 return NULL;
399 }
400
401 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
402 {
403 int i;
404 struct snapshot *s;
405 FOR_EACH_SNAPSHOT(s, i, sl) {
406 if (snapshot_is_being_created(s))
407 continue;
408 if (is_reference_snapshot(s))
409 continue;
410 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
411 return s;
412 }
413 return NULL;
414 }
415
416 static int rename_incomplete_snapshot(int64_t start)
417 {
418 char *old_name;
419 int ret;
420
421 free(path_to_last_complete_snapshot);
422 ret = complete_name(start, get_current_time(),
423 &path_to_last_complete_snapshot);
424 if (ret < 0)
425 return ret;
426 old_name = incomplete_name(start);
427 ret = dss_rename(old_name, path_to_last_complete_snapshot);
428 if (ret >= 0)
429 DSS_NOTICE_LOG("%s -> %s\n", old_name,
430 path_to_last_complete_snapshot);
431 free(old_name);
432 return ret;
433 }
434
435 static int try_to_free_disk_space(void)
436 {
437 int ret;
438 struct snapshot_list sl;
439 struct snapshot *victim;
440 struct timeval now;
441 const char *why;
442 int low_disk_space;
443
444 ret = disk_space_low();
445 if (ret < 0)
446 return ret;
447 low_disk_space = ret;
448 gettimeofday(&now, NULL);
449 if (tv_diff(&next_removal_check, &now, NULL) > 0)
450 return 0;
451 if (!low_disk_space) {
452 if (conf.keep_redundant_given)
453 return 0;
454 if (snapshot_creation_status != HS_READY)
455 return 0;
456 if (next_snapshot_is_due())
457 return 0;
458 }
459 dss_get_snapshot_list(&sl);
460 ret = 0;
461 if (!low_disk_space && sl.num_snapshots <= 1)
462 goto out;
463 why = "outdated";
464 victim = find_outdated_snapshot(&sl);
465 if (victim)
466 goto remove;
467 why = "redundant";
468 victim = find_redundant_snapshot(&sl);
469 if (victim)
470 goto remove;
471 /* try harder only if disk space is low */
472 if (!low_disk_space)
473 goto out;
474 why = "orphaned";
475 victim = find_orphaned_snapshot(&sl);
476 if (victim)
477 goto remove;
478 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
479 victim = find_oldest_removable_snapshot(&sl);
480 if (victim)
481 goto remove;
482 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
483 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
484 goto out;
485 remove:
486 ret = pre_remove_hook(victim, why);
487 out:
488 free_snapshot_list(&sl);
489 return ret;
490 }
491
492 static int post_create_hook(void)
493 {
494 int ret, fds[3] = {0, 0, 0};
495 char *cmd;
496
497 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
498 conf.dest_dir_arg, path_to_last_complete_snapshot);
499 DSS_NOTICE_LOG("executing %s\n", cmd);
500 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
501 free(cmd);
502 if (ret < 0)
503 return ret;
504 snapshot_creation_status = HS_POST_RUNNING;
505 return ret;
506 }
507
508 static int post_remove_hook(void)
509 {
510 int ret, fds[3] = {0, 0, 0};
511 char *cmd;
512 struct snapshot *s = snapshot_currently_being_removed;
513
514 assert(s);
515
516 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
517 conf.dest_dir_arg, s->name);
518 DSS_NOTICE_LOG("executing %s\n", cmd);
519 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
520 free(cmd);
521 if (ret < 0)
522 return ret;
523 snapshot_removal_status = HS_POST_RUNNING;
524 return ret;
525 }
526
527 static void dss_kill(pid_t pid, int sig, const char *msg)
528 {
529 const char *signame, *process_name;
530
531 if (pid == 0)
532 return;
533 switch (sig) {
534 case SIGTERM: signame = "TERM"; break;
535 case SIGSTOP: signame = "STOP"; break;
536 case SIGCONT: signame = "CONT"; break;
537 default: signame = "????";
538 }
539
540 if (pid == create_pid)
541 process_name = "create";
542 else if (pid == remove_pid)
543 process_name = "remove";
544 else process_name = "??????";
545
546 if (msg)
547 DSS_INFO_LOG("%s\n", msg);
548 DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
549 sig, signame, (int)pid, process_name);
550 if (kill(pid, sig) >= 0)
551 return;
552 DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
553 sig, signame, (int)pid, process_name);
554 }
555
556 static void stop_create_process(void)
557 {
558 if (create_process_stopped)
559 return;
560 dss_kill(create_pid, SIGSTOP, "suspending create process");
561 create_process_stopped = 1;
562 }
563
564 static void restart_create_process(void)
565 {
566 if (!create_process_stopped)
567 return;
568 dss_kill(create_pid, SIGCONT, "resuming create process");
569 create_process_stopped = 0;
570 }
571
572 /**
573 * Print a log message about the exit status of a child.
574 */
575 static void log_termination_msg(pid_t pid, int status)
576 {
577 if (WIFEXITED(status))
578 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
579 WEXITSTATUS(status));
580 else if (WIFSIGNALED(status))
581 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
582 WTERMSIG(status));
583 else
584 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
585 }
586
587 static int wait_for_process(pid_t pid, int *status)
588 {
589 int ret;
590
591 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
592 for (;;) {
593 fd_set rfds;
594
595 FD_ZERO(&rfds);
596 FD_SET(signal_pipe, &rfds);
597 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
598 if (ret < 0)
599 break;
600 ret = next_signal();
601 if (!ret)
602 continue;
603 if (ret == SIGCHLD) {
604 ret = waitpid(pid, status, 0);
605 if (ret >= 0)
606 break;
607 if (errno != EINTR) { /* error */
608 ret = -ERRNO_TO_DSS_ERROR(errno);
609 break;
610 }
611 }
612 /* SIGINT or SIGTERM */
613 dss_kill(pid, SIGTERM, "killing child process");
614 }
615 if (ret < 0)
616 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
617 else
618 log_termination_msg(pid, *status);
619 return ret;
620 }
621
622 static void handle_pre_remove_exit(int status)
623 {
624 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
625 snapshot_removal_status = HS_READY;
626 gettimeofday(&next_removal_check, NULL);
627 next_removal_check.tv_sec += 60;
628 return;
629 }
630 snapshot_removal_status = HS_PRE_SUCCESS;
631 }
632
633 static int handle_rm_exit(int status)
634 {
635 if (!WIFEXITED(status)) {
636 snapshot_removal_status = HS_READY;
637 return -E_INVOLUNTARY_EXIT;
638 }
639 if (WEXITSTATUS(status)) {
640 snapshot_removal_status = HS_READY;
641 return -E_BAD_EXIT_CODE;
642 }
643 snapshot_removal_status = HS_SUCCESS;
644 return 1;
645 }
646
647 static void handle_post_remove_exit(void)
648 {
649 snapshot_removal_status = HS_READY;
650 }
651
652 static int handle_remove_exit(int status)
653 {
654 int ret;
655 struct snapshot *s = snapshot_currently_being_removed;
656
657 assert(s);
658 switch (snapshot_removal_status) {
659 case HS_PRE_RUNNING:
660 handle_pre_remove_exit(status);
661 ret = 1;
662 break;
663 case HS_RUNNING:
664 ret = handle_rm_exit(status);
665 break;
666 case HS_POST_RUNNING:
667 handle_post_remove_exit();
668 ret = 1;
669 break;
670 default:
671 ret = -E_BUG;
672 }
673 if (snapshot_removal_status == HS_READY) {
674 free(s->name);
675 free(s);
676 snapshot_currently_being_removed = NULL;
677 }
678 remove_pid = 0;
679 return ret;
680 }
681
682 static int wait_for_remove_process(void)
683 {
684 int status, ret;
685
686 assert(remove_pid);
687 assert(
688 snapshot_removal_status == HS_PRE_RUNNING ||
689 snapshot_removal_status == HS_RUNNING ||
690 snapshot_removal_status == HS_POST_RUNNING
691 );
692 ret = wait_for_process(remove_pid, &status);
693 if (ret < 0)
694 return ret;
695 return handle_remove_exit(status);
696 }
697
698 static int handle_rsync_exit(int status)
699 {
700 int es, ret;
701
702 if (!WIFEXITED(status)) {
703 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
704 ret = -E_INVOLUNTARY_EXIT;
705 snapshot_creation_status = HS_READY;
706 goto out;
707 }
708 es = WEXITSTATUS(status);
709 /*
710 * Restart rsync on non-fatal errors:
711 * 12: Error in rsync protocol data stream
712 * 13: Errors with program diagnostics
713 */
714 if (es == 12 || es == 13) {
715 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
716 (int)create_pid, es);
717 snapshot_creation_status = HS_NEEDS_RESTART;
718 next_snapshot_time = get_current_time() + 60;
719 ret = 1;
720 goto out;
721 }
722 if (es != 0 && es != 23 && es != 24) {
723 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
724 ret = -E_BAD_EXIT_CODE;
725 snapshot_creation_status = HS_READY;
726 goto out;
727 }
728 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
729 if (ret < 0)
730 goto out;
731 snapshot_creation_status = HS_SUCCESS;
732 free(name_of_reference_snapshot);
733 name_of_reference_snapshot = NULL;
734 out:
735 create_process_stopped = 0;
736 return ret;
737 }
738
739 static int handle_pre_create_hook_exit(int status)
740 {
741 int es, ret;
742 static int warn_count;
743
744 if (!WIFEXITED(status)) {
745 snapshot_creation_status = HS_READY;
746 ret = -E_INVOLUNTARY_EXIT;
747 goto out;
748 }
749 es = WEXITSTATUS(status);
750 if (es) {
751 if (!warn_count--) {
752 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
753 conf.pre_create_hook_arg, es);
754 DSS_NOTICE_LOG("deferring snapshot creation...\n");
755 warn_count = 60; /* warn only once per hour */
756 }
757 next_snapshot_time = get_current_time() + 60;
758 snapshot_creation_status = HS_READY;
759 ret = 0;
760 goto out;
761 }
762 warn_count = 0;
763 snapshot_creation_status = HS_PRE_SUCCESS;
764 ret = 1;
765 out:
766 return ret;
767 }
768
769 static int handle_sigchld(void)
770 {
771 pid_t pid;
772 int status, ret = reap_child(&pid, &status);
773
774 if (ret <= 0)
775 return ret;
776
777 if (pid == create_pid) {
778 switch (snapshot_creation_status) {
779 case HS_PRE_RUNNING:
780 ret = handle_pre_create_hook_exit(status);
781 break;
782 case HS_RUNNING:
783 ret = handle_rsync_exit(status);
784 break;
785 case HS_POST_RUNNING:
786 snapshot_creation_status = HS_READY;
787 ret = 1;
788 break;
789 default:
790 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
791 snapshot_creation_status);
792 return -E_BUG;
793 }
794 create_pid = 0;
795 return ret;
796 }
797 if (pid == remove_pid) {
798 ret = handle_remove_exit(status);
799 if (ret < 0)
800 return ret;
801 return ret;
802 }
803 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
804 return -E_BUG;
805 }
806
807 static int check_config(void)
808 {
809 if (conf.unit_interval_arg <= 0) {
810 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
811 return -E_INVALID_NUMBER;
812 }
813 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
814 if (conf.num_intervals_arg <= 0) {
815 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
816 return -E_INVALID_NUMBER;
817 }
818 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
819 return 1;
820 }
821
822 /*
823 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
824 * file was read successfully.
825 */
826 static int parse_config_file(int override)
827 {
828 int ret, config_file_exists;
829 char *config_file;
830 struct stat statbuf;
831 char *old_logfile_arg = NULL;
832 int old_daemon_given = 0;
833
834 if (conf.config_file_given)
835 config_file = dss_strdup(conf.config_file_arg);
836 else {
837 char *home = get_homedir();
838 config_file = make_message("%s/.dssrc", home);
839 free(home);
840 }
841 if (override) { /* SIGHUP */
842 if (conf.logfile_given)
843 old_logfile_arg = dss_strdup(conf.logfile_arg);
844 old_daemon_given = conf.daemon_given;
845 }
846
847 config_file_exists = !stat(config_file, &statbuf);
848 if (!config_file_exists && conf.config_file_given) {
849 ret = -ERRNO_TO_DSS_ERROR(errno);
850 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
851 goto out;
852 }
853 if (config_file_exists) {
854 struct cmdline_parser_params params = {
855 .override = override,
856 .initialize = 0,
857 .check_required = 1,
858 .check_ambiguity = 0,
859 .print_errors = 1
860 };
861 if (override) { /* invalidate all rsync options */
862 int i;
863
864 for (i = 0; i < conf.rsync_option_given; i++) {
865 free(conf.rsync_option_arg[i]);
866 conf.rsync_option_arg[i] = NULL;
867 }
868 conf.rsync_option_given = 0;
869 }
870 cmdline_parser_config_file(config_file, &conf, &params);
871 }
872 ret = check_config();
873 if (ret < 0)
874 goto out;
875 if (override) {
876 /* don't change daemon mode on SIGHUP */
877 conf.daemon_given = old_daemon_given;
878 close_log(logfile);
879 logfile = NULL;
880 if (conf.logfile_given)
881 free(old_logfile_arg);
882 else if (conf.daemon_given) { /* re-use old logfile */
883 conf.logfile_arg = old_logfile_arg;
884 conf.logfile_given = 1;
885 }
886 }
887 if (conf.logfile_given && conf.run_given && conf.daemon_given) {
888 logfile = open_log(conf.logfile_arg);
889 log_welcome(conf.loglevel_arg);
890 }
891 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
892 ret = config_file_exists;
893 out:
894 free(config_file);
895 if (ret < 0)
896 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
897 return ret;
898 }
899
900 static int change_to_dest_dir(void)
901 {
902 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
903 return dss_chdir(conf.dest_dir_arg);
904 }
905
906 static void dump_dss_config(const char *msg)
907 {
908 if (conf.loglevel_arg > INFO)
909 return;
910 DSS_INFO_LOG("%s\n", msg);
911 cmdline_parser_dump(logfile? logfile : stderr, &conf);
912 }
913
914 static int handle_sighup(void)
915 {
916 int ret;
917
918 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
919 dump_dss_config("current config");
920 ret = parse_config_file(1);
921 if (ret < 0)
922 return ret;
923 dump_dss_config("new config");
924 invalidate_next_snapshot_time();
925 return change_to_dest_dir();
926 }
927
928 static int handle_signal(void)
929 {
930 int sig, ret = next_signal();
931
932 if (ret <= 0)
933 goto out;
934 sig = ret;
935 switch (sig) {
936 case SIGINT:
937 case SIGTERM:
938 restart_create_process();
939 dss_kill(create_pid, SIGTERM, NULL);
940 dss_kill(remove_pid, SIGTERM, NULL);
941 ret = -E_SIGNAL;
942 break;
943 case SIGHUP:
944 ret = handle_sighup();
945 break;
946 case SIGCHLD:
947 ret = handle_sigchld();
948 break;
949 }
950 out:
951 if (ret < 0)
952 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
953 return ret;
954 }
955
956 /*
957 * We can not use rsync locally if the local user is different from the remote
958 * user or if the src dir is not on the local host (or both).
959 */
960 static int use_rsync_locally(char *logname)
961 {
962 char *h = conf.remote_host_arg;
963
964 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
965 return 0;
966 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
967 return 0;
968 return 1;
969 }
970
971 static int rename_resume_snap(int64_t creation_time)
972 {
973 struct snapshot_list sl = {.num_snapshots = 0};
974 struct snapshot *s;
975 char *new_name = incomplete_name(creation_time);
976 int ret;
977
978 ret = 0;
979 if (conf.no_resume_given)
980 goto out;
981 dss_get_snapshot_list(&sl);
982 s = get_newest_snapshot(&sl);
983 if (!s)
984 goto out;
985 if ((s->flags & SS_COMPLETE) != 0) /* complete */
986 goto out;
987 DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
988 ret = dss_rename(s->name, new_name);
989 out:
990 if (ret >= 0)
991 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
992 free(new_name);
993 free_snapshot_list(&sl);
994 return ret;
995 }
996
997 static void create_rsync_argv(char ***argv, int64_t *num)
998 {
999 char *logname;
1000 int i = 0, j;
1001 struct snapshot_list sl;
1002
1003 dss_get_snapshot_list(&sl);
1004 assert(!name_of_reference_snapshot);
1005 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1006 free_snapshot_list(&sl);
1007
1008 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1009 (*argv)[i++] = dss_strdup("rsync");
1010 (*argv)[i++] = dss_strdup("-aq");
1011 (*argv)[i++] = dss_strdup("--delete");
1012 for (j = 0; j < conf.rsync_option_given; j++)
1013 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1014 if (name_of_reference_snapshot) {
1015 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1016 (*argv)[i++] = make_message("--link-dest=../%s",
1017 name_of_reference_snapshot);
1018 } else
1019 DSS_INFO_LOG("no suitable reference snapshot found\n");
1020 logname = dss_logname();
1021 if (use_rsync_locally(logname))
1022 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1023 else
1024 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1025 conf.remote_user_arg : logname,
1026 conf.remote_host_arg, conf.source_dir_arg);
1027 free(logname);
1028 *num = get_current_time();
1029 (*argv)[i++] = incomplete_name(*num);
1030 (*argv)[i++] = NULL;
1031 for (j = 0; j < i; j++)
1032 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1033 }
1034
1035 static void free_rsync_argv(char **argv)
1036 {
1037 int i;
1038
1039 if (!argv)
1040 return;
1041 for (i = 0; argv[i]; i++)
1042 free(argv[i]);
1043 free(argv);
1044 }
1045
1046 static int create_snapshot(char **argv)
1047 {
1048 int ret, fds[3] = {0, 0, 0};
1049
1050 ret = rename_resume_snap(current_snapshot_creation_time);
1051 if (ret < 0)
1052 return ret;
1053 ret = dss_exec(&create_pid, argv[0], argv, fds);
1054 if (ret < 0)
1055 return ret;
1056 snapshot_creation_status = HS_RUNNING;
1057 return ret;
1058 }
1059
1060 static int select_loop(void)
1061 {
1062 int ret;
1063 /* check every 60 seconds for free disk space */
1064 struct timeval tv;
1065 char **rsync_argv = NULL;
1066
1067 for (;;) {
1068 fd_set rfds;
1069 struct timeval *tvp;
1070
1071 if (remove_pid)
1072 tvp = NULL; /* sleep until rm hook/process dies */
1073 else { /* sleep one minute */
1074 tv.tv_sec = 60;
1075 tv.tv_usec = 0;
1076 tvp = &tv;
1077 }
1078 FD_ZERO(&rfds);
1079 FD_SET(signal_pipe, &rfds);
1080 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1081 if (ret < 0)
1082 goto out;
1083 if (FD_ISSET(signal_pipe, &rfds)) {
1084 ret = handle_signal();
1085 if (ret < 0)
1086 goto out;
1087 }
1088 if (remove_pid)
1089 continue;
1090 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1091 ret = exec_rm();
1092 if (ret < 0)
1093 goto out;
1094 continue;
1095 }
1096 if (snapshot_removal_status == HS_SUCCESS) {
1097 ret = post_remove_hook();
1098 if (ret < 0)
1099 goto out;
1100 continue;
1101 }
1102 ret = try_to_free_disk_space();
1103 if (ret < 0)
1104 goto out;
1105 if (snapshot_removal_status != HS_READY) {
1106 stop_create_process();
1107 continue;
1108 }
1109 restart_create_process();
1110 switch (snapshot_creation_status) {
1111 case HS_READY:
1112 if (!next_snapshot_is_due())
1113 continue;
1114 ret = pre_create_hook();
1115 if (ret < 0)
1116 goto out;
1117 continue;
1118 case HS_PRE_RUNNING:
1119 case HS_RUNNING:
1120 case HS_POST_RUNNING:
1121 continue;
1122 case HS_PRE_SUCCESS:
1123 if (!name_of_reference_snapshot) {
1124 free_rsync_argv(rsync_argv);
1125 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1126 }
1127 ret = create_snapshot(rsync_argv);
1128 if (ret < 0)
1129 goto out;
1130 continue;
1131 case HS_NEEDS_RESTART:
1132 if (!next_snapshot_is_due())
1133 continue;
1134 ret = create_snapshot(rsync_argv);
1135 if (ret < 0)
1136 goto out;
1137 continue;
1138 case HS_SUCCESS:
1139 ret = post_create_hook();
1140 if (ret < 0)
1141 goto out;
1142 continue;
1143 }
1144 }
1145 out:
1146 return ret;
1147 }
1148
1149 static void exit_hook(int exit_code)
1150 {
1151 int fds[3] = {0, 0, 0};
1152 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1153 pid_t pid;
1154
1155 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1156 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1157 }
1158
1159 static int com_run(void)
1160 {
1161 int ret;
1162
1163 if (conf.dry_run_given) {
1164 DSS_ERROR_LOG("dry_run not supported by this command\n");
1165 return -E_SYNTAX;
1166 }
1167 ret = install_sighandler(SIGHUP);
1168 if (ret < 0)
1169 return ret;
1170 ret = select_loop();
1171 if (ret >= 0) /* impossible */
1172 ret = -E_BUG;
1173 exit_hook(ret);
1174 return ret;
1175 }
1176
1177 static int com_prune(void)
1178 {
1179 int ret;
1180 struct snapshot_list sl;
1181 struct snapshot *victim;
1182 struct disk_space ds;
1183 const char *why;
1184
1185 ret = get_disk_space(".", &ds);
1186 if (ret < 0)
1187 return ret;
1188 log_disk_space(&ds);
1189 dss_get_snapshot_list(&sl);
1190 why = "outdated";
1191 victim = find_outdated_snapshot(&sl);
1192 if (victim)
1193 goto rm;
1194 why = "redundant";
1195 victim = find_redundant_snapshot(&sl);
1196 if (victim)
1197 goto rm;
1198 ret = 0;
1199 goto out;
1200 rm:
1201 if (conf.dry_run_given) {
1202 dss_msg("%s snapshot %s (interval = %i)\n",
1203 why, victim->name, victim->interval);
1204 ret = 0;
1205 goto out;
1206 }
1207 ret = pre_remove_hook(victim, why);
1208 if (ret < 0)
1209 goto out;
1210 if (snapshot_removal_status == HS_PRE_RUNNING) {
1211 ret = wait_for_remove_process();
1212 if (ret < 0)
1213 goto out;
1214 if (snapshot_removal_status != HS_PRE_SUCCESS)
1215 goto out;
1216 }
1217 ret = exec_rm();
1218 if (ret < 0)
1219 goto out;
1220 ret = wait_for_remove_process();
1221 if (ret < 0)
1222 goto out;
1223 if (snapshot_removal_status != HS_SUCCESS)
1224 goto out;
1225 ret = post_remove_hook();
1226 if (ret < 0)
1227 goto out;
1228 if (snapshot_removal_status != HS_POST_RUNNING)
1229 goto out;
1230 ret = wait_for_remove_process();
1231 if (ret < 0)
1232 goto out;
1233 ret = 1;
1234 out:
1235 free_snapshot_list(&sl);
1236 return ret;
1237 }
1238
1239 static int com_create(void)
1240 {
1241 int ret, status;
1242 char **rsync_argv;
1243
1244 if (conf.dry_run_given) {
1245 int i;
1246 char *msg = NULL;
1247 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1248 for (i = 0; rsync_argv[i]; i++) {
1249 char *tmp = msg;
1250 msg = make_message("%s%s%s", tmp? tmp : "",
1251 tmp? " " : "", rsync_argv[i]);
1252 free(tmp);
1253 }
1254 free_rsync_argv(rsync_argv);
1255 dss_msg("%s\n", msg);
1256 free(msg);
1257 return 1;
1258 }
1259 ret = pre_create_hook();
1260 if (ret < 0)
1261 return ret;
1262 if (create_pid) {
1263 ret = wait_for_process(create_pid, &status);
1264 if (ret < 0)
1265 return ret;
1266 ret = handle_pre_create_hook_exit(status);
1267 if (ret <= 0) /* error, or pre-create failed */
1268 return ret;
1269 }
1270 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1271 ret = create_snapshot(rsync_argv);
1272 if (ret < 0)
1273 goto out;
1274 ret = wait_for_process(create_pid, &status);
1275 if (ret < 0)
1276 goto out;
1277 ret = handle_rsync_exit(status);
1278 if (ret < 0)
1279 goto out;
1280 post_create_hook();
1281 if (create_pid)
1282 ret = wait_for_process(create_pid, &status);
1283 out:
1284 free_rsync_argv(rsync_argv);
1285 return ret;
1286 }
1287
1288 static int com_ls(void)
1289 {
1290 int i;
1291 struct snapshot_list sl;
1292 struct snapshot *s;
1293
1294 dss_get_snapshot_list(&sl);
1295 FOR_EACH_SNAPSHOT(s, i, &sl) {
1296 int64_t d = 0;
1297 if (s->flags & SS_COMPLETE)
1298 d = (s->completion_time - s->creation_time) / 60;
1299 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1300 };
1301 free_snapshot_list(&sl);
1302 return 1;
1303 }
1304
1305 static int setup_signal_handling(void)
1306 {
1307 int ret;
1308
1309 DSS_INFO_LOG("setting up signal handlers\n");
1310 signal_pipe = signal_init(); /* always successful */
1311 ret = install_sighandler(SIGINT);
1312 if (ret < 0)
1313 return ret;
1314 ret = install_sighandler(SIGTERM);
1315 if (ret < 0)
1316 return ret;
1317 return install_sighandler(SIGCHLD);
1318 }
1319
1320 /**
1321 * The main function of dss.
1322 *
1323 * \param argc Usual argument count.
1324 * \param argv Usual argument vector.
1325 */
1326 int main(int argc, char **argv)
1327 {
1328 int ret;
1329 struct cmdline_parser_params params = {
1330 .override = 0,
1331 .initialize = 1,
1332 .check_required = 0,
1333 .check_ambiguity = 0,
1334 .print_errors = 1
1335 };
1336
1337 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1338 ret = parse_config_file(0);
1339 if (ret < 0)
1340 goto out;
1341 if (ret == 0) { /* no config file given */
1342 /*
1343 * Parse the command line options again, but this time check
1344 * that all required options are given.
1345 */
1346 params = (struct cmdline_parser_params) {
1347 .override = 1,
1348 .initialize = 1,
1349 .check_required = 1,
1350 .check_ambiguity = 1,
1351 .print_errors = 1
1352 };
1353 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1354 }
1355 if (conf.daemon_given)
1356 daemon_init();
1357 dump_dss_config("dss configuration");
1358 ret = change_to_dest_dir();
1359 if (ret < 0)
1360 goto out;
1361 ret = setup_signal_handling();
1362 if (ret < 0)
1363 goto out;
1364 ret = call_command_handler();
1365 out:
1366 if (ret < 0)
1367 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1368 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1369 }