Merge branch 't/recycling'
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008-2010 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 static const char const *hook_status_description[] = {HOOK_STATUS_ARRAY};
68
69 /* may be called with ds == NULL. */
70 static int disk_space_low(struct disk_space *ds)
71 {
72 struct disk_space ds_struct;
73
74 if (!ds) {
75 int ret = get_disk_space(".", &ds_struct);
76 if (ret < 0)
77 return ret;
78 ds = &ds_struct;
79 }
80 if (conf.min_free_mb_arg)
81 if (ds->free_mb < conf.min_free_mb_arg)
82 return 1;
83 if (conf.min_free_percent_arg)
84 if (ds->percent_free < conf.min_free_percent_arg)
85 return 1;
86 if (conf.min_free_percent_inodes_arg)
87 if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
88 return 1;
89 return 0;
90 }
91
92 static void dump_dss_config(const char *msg)
93 {
94 const char dash[] = "-----------------------------";
95 int ret;
96 FILE *log = logfile? logfile : stderr;
97 struct disk_space ds;
98 int64_t now = get_current_time();
99
100 if (conf.loglevel_arg > INFO)
101 return;
102
103 fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
104 fprintf(log, "\n*** disk space ***\n\n");
105 ret = get_disk_space(".", &ds);
106 if (ret >= 0) {
107 DSS_INFO_LOG("disk space low: %s\n", disk_space_low(&ds)?
108 "yes" : "no");
109 log_disk_space(&ds);
110 } else
111 DSS_ERROR_LOG("can not get free disk space: %s\n",
112 dss_strerror(-ret));
113
114 /* we continue on errors from get_disk_space */
115
116 fprintf(log, "\n*** command line and config file options ***\n\n");
117 cmdline_parser_dump(log, &conf);
118 fprintf(log, "\n*** internal state ***\n\n");
119 fprintf(log,
120 "pid: %d\n"
121 "logile: %s\n"
122 "snapshot_currently_being_removed: %s\n"
123 "path_to_last_complete_snapshot: %s\n"
124 "reference_snapshot: %s\n"
125 "snapshot_creation_status: %s\n"
126 "snapshot_removal_status: %s\n"
127 ,
128 (int) getpid(),
129 logfile? conf.logfile_arg : "stderr",
130 snapshot_currently_being_removed?
131 snapshot_currently_being_removed->name : "(none)",
132 path_to_last_complete_snapshot?
133 path_to_last_complete_snapshot : "(none)",
134 name_of_reference_snapshot?
135 name_of_reference_snapshot : "(none)",
136 hook_status_description[snapshot_creation_status],
137 hook_status_description[snapshot_removal_status]
138 );
139 if (create_pid != 0)
140 fprintf(log,
141 "create_pid: %" PRId32 "\n"
142 "create process is %sstopped\n"
143 ,
144 create_pid,
145 create_process_stopped? "" : "not "
146 );
147 if (remove_pid != 0)
148 fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
149 if (next_snapshot_time != 0)
150 fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
151 next_snapshot_time - now);
152 if (current_snapshot_creation_time != 0)
153 fprintf(log, "current_snapshot_creation_time: %"
154 PRId64 " (%" PRId64 " seconds ago)\n",
155 current_snapshot_creation_time,
156 now - current_snapshot_creation_time
157 );
158 if (next_removal_check.tv_sec != 0) {
159 fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
160 (long long unsigned)next_removal_check.tv_sec,
161 now - (long long unsigned)next_removal_check.tv_sec
162 );
163
164 }
165 fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
166 }
167
168 /* a litte cpp magic helps to DRY */
169 #define COMMANDS \
170 COMMAND(ls) \
171 COMMAND(create) \
172 COMMAND(prune) \
173 COMMAND(run)
174 #define COMMAND(x) static int com_ ##x(void);
175 COMMANDS
176 #undef COMMAND
177 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
178 static int call_command_handler(void)
179 {
180 COMMANDS
181 DSS_EMERG_LOG("BUG: did not find command handler\n");
182 return -E_BUG;
183 }
184 #undef COMMAND
185 #undef COMMANDS
186
187 /**
188 * The log function of dss.
189 *
190 * \param ll Loglevel.
191 * \param fml Usual format string.
192 *
193 * All DSS_XXX_LOG() macros use this function.
194 */
195 __printf_2_3 void dss_log(int ll, const char* fmt,...)
196 {
197 va_list argp;
198 FILE *outfd;
199 struct tm *tm;
200 time_t t1;
201 char str[255] = "";
202
203 if (ll < conf.loglevel_arg)
204 return;
205 outfd = logfile? logfile : stderr;
206 time(&t1);
207 tm = localtime(&t1);
208 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
209 fprintf(outfd, "%s ", str);
210 if (conf.loglevel_arg <= INFO)
211 fprintf(outfd, "%i: ", ll);
212 va_start(argp, fmt);
213 vfprintf(outfd, fmt, argp);
214 va_end(argp);
215 }
216
217 /**
218 * Print a message either to stdout or to the log file.
219 */
220 static __printf_1_2 void dss_msg(const char* fmt,...)
221 {
222 FILE *outfd = conf.daemon_given? logfile : stdout;
223 va_list argp;
224 va_start(argp, fmt);
225 vfprintf(outfd, fmt, argp);
226 va_end(argp);
227 }
228
229 static void dss_get_snapshot_list(struct snapshot_list *sl)
230 {
231 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
232 }
233
234 static int64_t compute_next_snapshot_time(void)
235 {
236 int64_t x = 0, now = get_current_time(), unit_interval
237 = 24 * 3600 * conf.unit_interval_arg, ret;
238 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
239 num_complete_snapshots = 0;
240 int i;
241 struct snapshot *s = NULL;
242 struct snapshot_list sl;
243
244 dss_get_snapshot_list(&sl);
245 FOR_EACH_SNAPSHOT(s, i, &sl) {
246 if (!(s->flags & SS_COMPLETE))
247 continue;
248 num_complete_snapshots++;
249 x += s->completion_time - s->creation_time;
250 }
251 assert(x >= 0);
252
253 ret = now;
254 if (num_complete_snapshots == 0)
255 goto out;
256 x /= num_complete_snapshots; /* avg time to create one snapshot */
257 if (unit_interval < x * wanted) /* oops, no sleep at all */
258 goto out;
259 ret = s->completion_time + unit_interval / wanted - x;
260 out:
261 free_snapshot_list(&sl);
262 return ret;
263 }
264
265 static inline void invalidate_next_snapshot_time(void)
266 {
267 next_snapshot_time = 0;
268 }
269
270 static inline int next_snapshot_time_is_valid(void)
271 {
272 return next_snapshot_time != 0;
273 }
274
275 static int next_snapshot_is_due(void)
276 {
277 int64_t now = get_current_time();
278
279 if (!next_snapshot_time_is_valid())
280 next_snapshot_time = compute_next_snapshot_time();
281 if (next_snapshot_time <= now) {
282 DSS_DEBUG_LOG("next snapshot: now\n");
283 return 1;
284 }
285 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
286 next_snapshot_time - now);
287 return 0;
288 }
289
290 static int pre_create_hook(void)
291 {
292 int ret, fds[3] = {0, 0, 0};
293
294 assert(snapshot_creation_status == HS_READY);
295 /* make sure that the next snapshot time will be recomputed */
296 invalidate_next_snapshot_time();
297 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
298 ret = dss_exec_cmdline_pid(&create_pid,
299 conf.pre_create_hook_arg, fds);
300 if (ret < 0)
301 return ret;
302 snapshot_creation_status = HS_PRE_RUNNING;
303 return ret;
304 }
305
306 static int pre_remove_hook(struct snapshot *s, const char *why)
307 {
308 int ret, fds[3] = {0, 0, 0};
309 char *cmd;
310
311 if (!s)
312 return 0;
313 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
314 assert(snapshot_removal_status == HS_READY);
315 assert(remove_pid == 0);
316 assert(!snapshot_currently_being_removed);
317
318 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
319 *snapshot_currently_being_removed = *s;
320 snapshot_currently_being_removed->name = dss_strdup(s->name);
321
322 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
323 conf.dest_dir_arg, s->name);
324 DSS_DEBUG_LOG("executing %s\n", cmd);
325 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
326 free(cmd);
327 if (ret < 0)
328 return ret;
329 snapshot_removal_status = HS_PRE_RUNNING;
330 return ret;
331 }
332
333 static int exec_rm(void)
334 {
335 struct snapshot *s = snapshot_currently_being_removed;
336 int fds[3] = {0, 0, 0};
337 char *new_name = being_deleted_name(s);
338 char *argv[] = {"rm", "-rf", new_name, NULL};
339 int ret;
340
341 assert(snapshot_removal_status == HS_PRE_SUCCESS);
342 assert(remove_pid == 0);
343
344 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
345 ret = dss_rename(s->name, new_name);
346 if (ret < 0)
347 goto out;
348 ret = dss_exec(&remove_pid, argv[0], argv, fds);
349 if (ret < 0)
350 goto out;
351 snapshot_removal_status = HS_RUNNING;
352 out:
353 free(new_name);
354 return ret;
355 }
356
357 static int snapshot_is_being_created(struct snapshot *s)
358 {
359 return s->creation_time == current_snapshot_creation_time;
360 }
361
362 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
363 {
364 struct snapshot *s;
365 int i;
366
367 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
368 FOR_EACH_SNAPSHOT(s, i, sl) {
369 if (snapshot_is_being_created(s))
370 continue;
371 /*
372 * We know that no rm is currently running, so if s is marked
373 * as being deleted, a previously started rm must have failed.
374 */
375 if (s->flags & SS_BEING_DELETED)
376 return s;
377
378 if (s->flags & SS_COMPLETE) /* good snapshot */
379 continue;
380 /*
381 * This snapshot is incomplete and it is not the snapshot
382 * currently being created. However, we must not remove it if
383 * rsync is about to be restarted. As only the newest snapshot
384 * can be restarted, this snapshot is orphaned if it is not the
385 * newest snapshot or if we are not about to restart rsync.
386 */
387 if (get_newest_snapshot(sl) != s)
388 return s;
389 if (snapshot_creation_status != HS_NEEDS_RESTART)
390 return s;
391 }
392 /* no orphaned snapshots */
393 return NULL;
394 }
395
396 static int is_reference_snapshot(struct snapshot *s)
397 {
398 if (!name_of_reference_snapshot)
399 return 0;
400 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
401 }
402
403 /*
404 * return: 0: no redundant snapshots, 1: rm process started, negative: error
405 */
406 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
407 {
408 int i, interval;
409 struct snapshot *s;
410 unsigned missing = 0;
411
412 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
413 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
414 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
415 unsigned num = sl->interval_count[interval];
416 struct snapshot *victim = NULL, *prev = NULL;
417 int64_t score = LONG_MAX;
418
419 if (keep >= num)
420 missing += keep - num;
421 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
422 // interval, keep, num, missing);
423 if (keep + missing >= num)
424 continue;
425 /* redundant snapshot in this interval, pick snapshot with lowest score */
426 FOR_EACH_SNAPSHOT(s, i, sl) {
427 int64_t this_score;
428
429 if (snapshot_is_being_created(s))
430 continue;
431 if (is_reference_snapshot(s))
432 continue;
433 //DSS_DEBUG_LOG("checking %s\n", s->name);
434 if (s->interval > interval) {
435 prev = s;
436 continue;
437 }
438 if (s->interval < interval)
439 break;
440 if (!victim) {
441 victim = s;
442 prev = s;
443 continue;
444 }
445 assert(prev);
446 /* check if s is a better victim */
447 this_score = s->creation_time - prev->creation_time;
448 assert(this_score >= 0);
449 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
450 if (this_score < score) {
451 score = this_score;
452 victim = s;
453 }
454 prev = s;
455 }
456 assert(victim);
457 return victim;
458 }
459 return NULL;
460 }
461
462 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
463 {
464 int i;
465 struct snapshot *s;
466
467 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
468 conf.num_intervals_arg);
469 FOR_EACH_SNAPSHOT(s, i, sl) {
470 if (snapshot_is_being_created(s))
471 continue;
472 if (is_reference_snapshot(s))
473 continue;
474 if (s->interval < conf.num_intervals_arg)
475 continue;
476 return s;
477 }
478 return NULL;
479 }
480
481 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
482 {
483 int i;
484 struct snapshot *s;
485 FOR_EACH_SNAPSHOT(s, i, sl) {
486 if (snapshot_is_being_created(s))
487 continue;
488 if (is_reference_snapshot(s))
489 continue;
490 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
491 return s;
492 }
493 return NULL;
494 }
495
496 static int rename_incomplete_snapshot(int64_t start)
497 {
498 char *old_name;
499 int ret;
500
501 free(path_to_last_complete_snapshot);
502 ret = complete_name(start, get_current_time(),
503 &path_to_last_complete_snapshot);
504 if (ret < 0)
505 return ret;
506 old_name = incomplete_name(start);
507 ret = dss_rename(old_name, path_to_last_complete_snapshot);
508 if (ret >= 0)
509 DSS_NOTICE_LOG("%s -> %s\n", old_name,
510 path_to_last_complete_snapshot);
511 free(old_name);
512 return ret;
513 }
514
515 static int try_to_free_disk_space(void)
516 {
517 int ret;
518 struct snapshot_list sl;
519 struct snapshot *victim;
520 struct timeval now;
521 const char *why;
522 int low_disk_space;
523
524 ret = disk_space_low(NULL);
525 if (ret < 0)
526 return ret;
527 low_disk_space = ret;
528 gettimeofday(&now, NULL);
529 if (tv_diff(&next_removal_check, &now, NULL) > 0)
530 return 0;
531 if (!low_disk_space) {
532 if (conf.keep_redundant_given)
533 return 0;
534 if (snapshot_creation_status != HS_READY)
535 return 0;
536 if (next_snapshot_is_due())
537 return 0;
538 }
539 dss_get_snapshot_list(&sl);
540 ret = 0;
541 if (!low_disk_space && sl.num_snapshots <= 1)
542 goto out;
543 why = "outdated";
544 victim = find_outdated_snapshot(&sl);
545 if (victim)
546 goto remove;
547 why = "redundant";
548 victim = find_redundant_snapshot(&sl);
549 if (victim)
550 goto remove;
551 /* try harder only if disk space is low */
552 if (!low_disk_space)
553 goto out;
554 why = "orphaned";
555 victim = find_orphaned_snapshot(&sl);
556 if (victim)
557 goto remove;
558 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
559 victim = find_oldest_removable_snapshot(&sl);
560 if (victim)
561 goto remove;
562 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
563 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
564 goto out;
565 remove:
566 ret = pre_remove_hook(victim, why);
567 out:
568 free_snapshot_list(&sl);
569 return ret;
570 }
571
572 static int post_create_hook(void)
573 {
574 int ret, fds[3] = {0, 0, 0};
575 char *cmd;
576
577 cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
578 conf.dest_dir_arg, path_to_last_complete_snapshot);
579 DSS_NOTICE_LOG("executing %s\n", cmd);
580 ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
581 free(cmd);
582 if (ret < 0)
583 return ret;
584 snapshot_creation_status = HS_POST_RUNNING;
585 return ret;
586 }
587
588 static int post_remove_hook(void)
589 {
590 int ret, fds[3] = {0, 0, 0};
591 char *cmd;
592 struct snapshot *s = snapshot_currently_being_removed;
593
594 assert(s);
595
596 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
597 conf.dest_dir_arg, s->name);
598 DSS_NOTICE_LOG("executing %s\n", cmd);
599 ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
600 free(cmd);
601 if (ret < 0)
602 return ret;
603 snapshot_removal_status = HS_POST_RUNNING;
604 return ret;
605 }
606
607 static void dss_kill(pid_t pid, int sig, const char *msg)
608 {
609 const char *signame, *process_name;
610
611 if (pid == 0)
612 return;
613 switch (sig) {
614 case SIGTERM: signame = "TERM"; break;
615 case SIGSTOP: signame = "STOP"; break;
616 case SIGCONT: signame = "CONT"; break;
617 default: signame = "????";
618 }
619
620 if (pid == create_pid)
621 process_name = "create";
622 else if (pid == remove_pid)
623 process_name = "remove";
624 else process_name = "??????";
625
626 if (msg)
627 DSS_INFO_LOG("%s\n", msg);
628 DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
629 sig, signame, (int)pid, process_name);
630 if (kill(pid, sig) >= 0)
631 return;
632 DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
633 sig, signame, (int)pid, process_name);
634 }
635
636 static void stop_create_process(void)
637 {
638 if (create_process_stopped)
639 return;
640 dss_kill(create_pid, SIGSTOP, "suspending create process");
641 create_process_stopped = 1;
642 }
643
644 static void restart_create_process(void)
645 {
646 if (!create_process_stopped)
647 return;
648 dss_kill(create_pid, SIGCONT, "resuming create process");
649 create_process_stopped = 0;
650 }
651
652 /**
653 * Print a log message about the exit status of a child.
654 */
655 static void log_termination_msg(pid_t pid, int status)
656 {
657 if (WIFEXITED(status))
658 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
659 WEXITSTATUS(status));
660 else if (WIFSIGNALED(status))
661 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
662 WTERMSIG(status));
663 else
664 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
665 }
666
667 static int wait_for_process(pid_t pid, int *status)
668 {
669 int ret;
670
671 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
672 for (;;) {
673 fd_set rfds;
674
675 FD_ZERO(&rfds);
676 FD_SET(signal_pipe, &rfds);
677 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
678 if (ret < 0)
679 break;
680 ret = next_signal();
681 if (!ret)
682 continue;
683 if (ret == SIGCHLD) {
684 ret = waitpid(pid, status, 0);
685 if (ret >= 0)
686 break;
687 if (errno != EINTR) { /* error */
688 ret = -ERRNO_TO_DSS_ERROR(errno);
689 break;
690 }
691 }
692 /* SIGINT or SIGTERM */
693 dss_kill(pid, SIGTERM, "killing child process");
694 }
695 if (ret < 0)
696 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
697 else
698 log_termination_msg(pid, *status);
699 return ret;
700 }
701
702 static void handle_pre_remove_exit(int status)
703 {
704 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
705 snapshot_removal_status = HS_READY;
706 gettimeofday(&next_removal_check, NULL);
707 next_removal_check.tv_sec += 60;
708 return;
709 }
710 snapshot_removal_status = HS_PRE_SUCCESS;
711 }
712
713 static int handle_rm_exit(int status)
714 {
715 if (!WIFEXITED(status)) {
716 snapshot_removal_status = HS_READY;
717 return -E_INVOLUNTARY_EXIT;
718 }
719 if (WEXITSTATUS(status)) {
720 snapshot_removal_status = HS_READY;
721 return -E_BAD_EXIT_CODE;
722 }
723 snapshot_removal_status = HS_SUCCESS;
724 return 1;
725 }
726
727 static void handle_post_remove_exit(void)
728 {
729 snapshot_removal_status = HS_READY;
730 }
731
732 static int handle_remove_exit(int status)
733 {
734 int ret;
735 struct snapshot *s = snapshot_currently_being_removed;
736
737 assert(s);
738 switch (snapshot_removal_status) {
739 case HS_PRE_RUNNING:
740 handle_pre_remove_exit(status);
741 ret = 1;
742 break;
743 case HS_RUNNING:
744 ret = handle_rm_exit(status);
745 break;
746 case HS_POST_RUNNING:
747 handle_post_remove_exit();
748 ret = 1;
749 break;
750 default:
751 ret = -E_BUG;
752 }
753 if (snapshot_removal_status == HS_READY) {
754 free(s->name);
755 free(s);
756 snapshot_currently_being_removed = NULL;
757 }
758 remove_pid = 0;
759 return ret;
760 }
761
762 static int wait_for_remove_process(void)
763 {
764 int status, ret;
765
766 assert(remove_pid);
767 assert(
768 snapshot_removal_status == HS_PRE_RUNNING ||
769 snapshot_removal_status == HS_RUNNING ||
770 snapshot_removal_status == HS_POST_RUNNING
771 );
772 ret = wait_for_process(remove_pid, &status);
773 if (ret < 0)
774 return ret;
775 return handle_remove_exit(status);
776 }
777
778 static int handle_rsync_exit(int status)
779 {
780 int es, ret;
781
782 if (!WIFEXITED(status)) {
783 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
784 ret = -E_INVOLUNTARY_EXIT;
785 snapshot_creation_status = HS_READY;
786 goto out;
787 }
788 es = WEXITSTATUS(status);
789 /*
790 * Restart rsync on non-fatal errors:
791 * 12: Error in rsync protocol data stream
792 * 13: Errors with program diagnostics
793 */
794 if (es == 12 || es == 13) {
795 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
796 (int)create_pid, es);
797 snapshot_creation_status = HS_NEEDS_RESTART;
798 next_snapshot_time = get_current_time() + 60;
799 ret = 1;
800 goto out;
801 }
802 if (es != 0 && es != 23 && es != 24) {
803 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
804 ret = -E_BAD_EXIT_CODE;
805 snapshot_creation_status = HS_READY;
806 goto out;
807 }
808 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
809 if (ret < 0)
810 goto out;
811 snapshot_creation_status = HS_SUCCESS;
812 free(name_of_reference_snapshot);
813 name_of_reference_snapshot = NULL;
814 out:
815 create_process_stopped = 0;
816 return ret;
817 }
818
819 static int handle_pre_create_hook_exit(int status)
820 {
821 int es, ret;
822 static int warn_count;
823
824 if (!WIFEXITED(status)) {
825 snapshot_creation_status = HS_READY;
826 ret = -E_INVOLUNTARY_EXIT;
827 goto out;
828 }
829 es = WEXITSTATUS(status);
830 if (es) {
831 if (!warn_count--) {
832 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
833 conf.pre_create_hook_arg, es);
834 DSS_NOTICE_LOG("deferring snapshot creation...\n");
835 warn_count = 60; /* warn only once per hour */
836 }
837 next_snapshot_time = get_current_time() + 60;
838 snapshot_creation_status = HS_READY;
839 ret = 0;
840 goto out;
841 }
842 warn_count = 0;
843 snapshot_creation_status = HS_PRE_SUCCESS;
844 ret = 1;
845 out:
846 return ret;
847 }
848
849 static int handle_sigchld(void)
850 {
851 pid_t pid;
852 int status, ret = reap_child(&pid, &status);
853
854 if (ret <= 0)
855 return ret;
856
857 if (pid == create_pid) {
858 switch (snapshot_creation_status) {
859 case HS_PRE_RUNNING:
860 ret = handle_pre_create_hook_exit(status);
861 break;
862 case HS_RUNNING:
863 ret = handle_rsync_exit(status);
864 break;
865 case HS_POST_RUNNING:
866 snapshot_creation_status = HS_READY;
867 ret = 1;
868 break;
869 default:
870 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
871 snapshot_creation_status);
872 return -E_BUG;
873 }
874 create_pid = 0;
875 return ret;
876 }
877 if (pid == remove_pid) {
878 ret = handle_remove_exit(status);
879 if (ret < 0)
880 return ret;
881 return ret;
882 }
883 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
884 return -E_BUG;
885 }
886
887 static int check_config(void)
888 {
889 if (conf.unit_interval_arg <= 0) {
890 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
891 return -E_INVALID_NUMBER;
892 }
893 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
894 if (conf.num_intervals_arg <= 0) {
895 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
896 return -E_INVALID_NUMBER;
897 }
898 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
899 return 1;
900 }
901
902 /*
903 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
904 * file was read successfully.
905 */
906 static int parse_config_file(int override)
907 {
908 int ret, config_file_exists;
909 char *config_file;
910 struct stat statbuf;
911 char *old_logfile_arg = NULL;
912 int old_daemon_given = 0;
913
914 if (conf.config_file_given)
915 config_file = dss_strdup(conf.config_file_arg);
916 else {
917 char *home = get_homedir();
918 config_file = make_message("%s/.dssrc", home);
919 free(home);
920 }
921 if (override) { /* SIGHUP */
922 if (conf.logfile_given)
923 old_logfile_arg = dss_strdup(conf.logfile_arg);
924 old_daemon_given = conf.daemon_given;
925 }
926
927 config_file_exists = !stat(config_file, &statbuf);
928 if (!config_file_exists && conf.config_file_given) {
929 ret = -ERRNO_TO_DSS_ERROR(errno);
930 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
931 goto out;
932 }
933 if (config_file_exists) {
934 struct cmdline_parser_params params = {
935 .override = override,
936 .initialize = 0,
937 .check_required = 1,
938 .check_ambiguity = 0,
939 .print_errors = 1
940 };
941 if (override) { /* invalidate all rsync options */
942 int i;
943
944 for (i = 0; i < conf.rsync_option_given; i++) {
945 free(conf.rsync_option_arg[i]);
946 conf.rsync_option_arg[i] = NULL;
947 }
948 conf.rsync_option_given = 0;
949 }
950 cmdline_parser_config_file(config_file, &conf, &params);
951 }
952 ret = check_config();
953 if (ret < 0)
954 goto out;
955 if (override) {
956 /* don't change daemon mode on SIGHUP */
957 conf.daemon_given = old_daemon_given;
958 close_log(logfile);
959 logfile = NULL;
960 if (conf.logfile_given)
961 free(old_logfile_arg);
962 else if (conf.daemon_given) { /* re-use old logfile */
963 conf.logfile_arg = old_logfile_arg;
964 conf.logfile_given = 1;
965 }
966 }
967 if (conf.logfile_given && conf.run_given && conf.daemon_given) {
968 logfile = open_log(conf.logfile_arg);
969 log_welcome(conf.loglevel_arg);
970 }
971 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
972 ret = config_file_exists;
973 out:
974 free(config_file);
975 if (ret < 0)
976 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
977 return ret;
978 }
979
980 static int change_to_dest_dir(void)
981 {
982 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
983 return dss_chdir(conf.dest_dir_arg);
984 }
985
986 static int handle_sighup(void)
987 {
988 int ret;
989
990 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
991 dump_dss_config("old");
992 ret = parse_config_file(1);
993 if (ret < 0)
994 return ret;
995 dump_dss_config("reloaded");
996 invalidate_next_snapshot_time();
997 return change_to_dest_dir();
998 }
999
1000 static int handle_signal(void)
1001 {
1002 int sig, ret = next_signal();
1003
1004 if (ret <= 0)
1005 goto out;
1006 sig = ret;
1007 switch (sig) {
1008 case SIGINT:
1009 case SIGTERM:
1010 restart_create_process();
1011 dss_kill(create_pid, SIGTERM, NULL);
1012 dss_kill(remove_pid, SIGTERM, NULL);
1013 ret = -E_SIGNAL;
1014 break;
1015 case SIGHUP:
1016 ret = handle_sighup();
1017 break;
1018 case SIGCHLD:
1019 ret = handle_sigchld();
1020 break;
1021 }
1022 out:
1023 if (ret < 0)
1024 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1025 return ret;
1026 }
1027
1028 /*
1029 * We can not use rsync locally if the local user is different from the remote
1030 * user or if the src dir is not on the local host (or both).
1031 */
1032 static int use_rsync_locally(char *logname)
1033 {
1034 char *h = conf.remote_host_arg;
1035
1036 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1037 return 0;
1038 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1039 return 0;
1040 return 1;
1041 }
1042
1043 static int rename_resume_snap(int64_t creation_time)
1044 {
1045 struct snapshot_list sl = {.num_snapshots = 0};
1046 struct snapshot *s = NULL;
1047 char *new_name = incomplete_name(creation_time);
1048 int ret;
1049 const char *why;
1050
1051 ret = 0;
1052 if (conf.no_resume_given)
1053 goto out;
1054 dss_get_snapshot_list(&sl);
1055 /*
1056 * Snapshot recycling: We first look at the newest snapshot. If this
1057 * snapshot happens to be incomplete, the last rsync process was
1058 * aborted and we reuse this one. Otherwise we look at snapshots which
1059 * could be removed (outdated and redundant snapshots) as candidates
1060 * for recycling. If no outdated/redundant snapshot exists, we check if
1061 * there is an orphaned snapshot, which likely is useless anyway.
1062 *
1063 * Only if no existing snapshot is suitable for recycling, we bite the
1064 * bullet and create a new one.
1065 */
1066 s = get_newest_snapshot(&sl);
1067 if (!s) /* no snapshots at all */
1068 goto out;
1069 /* re-use last snapshot if it is incomplete */
1070 why = "aborted";
1071 if ((s->flags & SS_COMPLETE) == 0)
1072 goto out;
1073 why = "outdated";
1074 s = find_outdated_snapshot(&sl);
1075 if (s)
1076 goto out;
1077 why = "redundant";
1078 s = find_redundant_snapshot(&sl);
1079 if (s)
1080 goto out;
1081 why = "orphaned";
1082 s = find_orphaned_snapshot(&sl);
1083 out:
1084 if (s) {
1085 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1086 ret = dss_rename(s->name, new_name);
1087 }
1088 if (ret >= 0)
1089 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1090 free(new_name);
1091 free_snapshot_list(&sl);
1092 return ret;
1093 }
1094
1095 static void create_rsync_argv(char ***argv, int64_t *num)
1096 {
1097 char *logname;
1098 int i = 0, j;
1099 struct snapshot_list sl;
1100
1101 dss_get_snapshot_list(&sl);
1102 assert(!name_of_reference_snapshot);
1103 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1104 free_snapshot_list(&sl);
1105
1106 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1107 (*argv)[i++] = dss_strdup("rsync");
1108 (*argv)[i++] = dss_strdup("-aq");
1109 (*argv)[i++] = dss_strdup("--delete");
1110 for (j = 0; j < conf.rsync_option_given; j++)
1111 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1112 if (name_of_reference_snapshot) {
1113 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1114 (*argv)[i++] = make_message("--link-dest=../%s",
1115 name_of_reference_snapshot);
1116 } else
1117 DSS_INFO_LOG("no suitable reference snapshot found\n");
1118 logname = dss_logname();
1119 if (use_rsync_locally(logname))
1120 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1121 else
1122 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1123 conf.remote_user_arg : logname,
1124 conf.remote_host_arg, conf.source_dir_arg);
1125 free(logname);
1126 *num = get_current_time();
1127 (*argv)[i++] = incomplete_name(*num);
1128 (*argv)[i++] = NULL;
1129 for (j = 0; j < i; j++)
1130 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1131 }
1132
1133 static void free_rsync_argv(char **argv)
1134 {
1135 int i;
1136
1137 if (!argv)
1138 return;
1139 for (i = 0; argv[i]; i++)
1140 free(argv[i]);
1141 free(argv);
1142 }
1143
1144 static int create_snapshot(char **argv)
1145 {
1146 int ret, fds[3] = {0, 0, 0};
1147
1148 ret = rename_resume_snap(current_snapshot_creation_time);
1149 if (ret < 0)
1150 return ret;
1151 ret = dss_exec(&create_pid, argv[0], argv, fds);
1152 if (ret < 0)
1153 return ret;
1154 snapshot_creation_status = HS_RUNNING;
1155 return ret;
1156 }
1157
1158 static int select_loop(void)
1159 {
1160 int ret;
1161 /* check every 60 seconds for free disk space */
1162 struct timeval tv;
1163 char **rsync_argv = NULL;
1164
1165 for (;;) {
1166 fd_set rfds;
1167 struct timeval *tvp;
1168
1169 if (remove_pid)
1170 tvp = NULL; /* sleep until rm hook/process dies */
1171 else { /* sleep one minute */
1172 tv.tv_sec = 60;
1173 tv.tv_usec = 0;
1174 tvp = &tv;
1175 }
1176 FD_ZERO(&rfds);
1177 FD_SET(signal_pipe, &rfds);
1178 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1179 if (ret < 0)
1180 goto out;
1181 if (FD_ISSET(signal_pipe, &rfds)) {
1182 ret = handle_signal();
1183 if (ret < 0)
1184 goto out;
1185 }
1186 if (remove_pid)
1187 continue;
1188 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1189 ret = exec_rm();
1190 if (ret < 0)
1191 goto out;
1192 continue;
1193 }
1194 if (snapshot_removal_status == HS_SUCCESS) {
1195 ret = post_remove_hook();
1196 if (ret < 0)
1197 goto out;
1198 continue;
1199 }
1200 ret = try_to_free_disk_space();
1201 if (ret < 0)
1202 goto out;
1203 if (snapshot_removal_status != HS_READY) {
1204 stop_create_process();
1205 continue;
1206 }
1207 restart_create_process();
1208 switch (snapshot_creation_status) {
1209 case HS_READY:
1210 if (!next_snapshot_is_due())
1211 continue;
1212 ret = pre_create_hook();
1213 if (ret < 0)
1214 goto out;
1215 continue;
1216 case HS_PRE_RUNNING:
1217 case HS_RUNNING:
1218 case HS_POST_RUNNING:
1219 continue;
1220 case HS_PRE_SUCCESS:
1221 if (!name_of_reference_snapshot) {
1222 free_rsync_argv(rsync_argv);
1223 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1224 }
1225 ret = create_snapshot(rsync_argv);
1226 if (ret < 0)
1227 goto out;
1228 continue;
1229 case HS_NEEDS_RESTART:
1230 if (!next_snapshot_is_due())
1231 continue;
1232 ret = create_snapshot(rsync_argv);
1233 if (ret < 0)
1234 goto out;
1235 continue;
1236 case HS_SUCCESS:
1237 ret = post_create_hook();
1238 if (ret < 0)
1239 goto out;
1240 continue;
1241 }
1242 }
1243 out:
1244 return ret;
1245 }
1246
1247 static void exit_hook(int exit_code)
1248 {
1249 int fds[3] = {0, 0, 0};
1250 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1251 pid_t pid;
1252
1253 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1254 dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1255 }
1256
1257 static int com_run(void)
1258 {
1259 int ret;
1260
1261 if (conf.dry_run_given) {
1262 DSS_ERROR_LOG("dry_run not supported by this command\n");
1263 return -E_SYNTAX;
1264 }
1265 ret = install_sighandler(SIGHUP);
1266 if (ret < 0)
1267 return ret;
1268 ret = select_loop();
1269 if (ret >= 0) /* impossible */
1270 ret = -E_BUG;
1271 exit_hook(ret);
1272 return ret;
1273 }
1274
1275 static int com_prune(void)
1276 {
1277 int ret;
1278 struct snapshot_list sl;
1279 struct snapshot *victim;
1280 struct disk_space ds;
1281 const char *why;
1282
1283 ret = get_disk_space(".", &ds);
1284 if (ret < 0)
1285 return ret;
1286 log_disk_space(&ds);
1287 dss_get_snapshot_list(&sl);
1288 why = "outdated";
1289 victim = find_outdated_snapshot(&sl);
1290 if (victim)
1291 goto rm;
1292 why = "redundant";
1293 victim = find_redundant_snapshot(&sl);
1294 if (victim)
1295 goto rm;
1296 ret = 0;
1297 goto out;
1298 rm:
1299 if (conf.dry_run_given) {
1300 dss_msg("%s snapshot %s (interval = %i)\n",
1301 why, victim->name, victim->interval);
1302 ret = 0;
1303 goto out;
1304 }
1305 ret = pre_remove_hook(victim, why);
1306 if (ret < 0)
1307 goto out;
1308 if (snapshot_removal_status == HS_PRE_RUNNING) {
1309 ret = wait_for_remove_process();
1310 if (ret < 0)
1311 goto out;
1312 if (snapshot_removal_status != HS_PRE_SUCCESS)
1313 goto out;
1314 }
1315 ret = exec_rm();
1316 if (ret < 0)
1317 goto out;
1318 ret = wait_for_remove_process();
1319 if (ret < 0)
1320 goto out;
1321 if (snapshot_removal_status != HS_SUCCESS)
1322 goto out;
1323 ret = post_remove_hook();
1324 if (ret < 0)
1325 goto out;
1326 if (snapshot_removal_status != HS_POST_RUNNING)
1327 goto out;
1328 ret = wait_for_remove_process();
1329 if (ret < 0)
1330 goto out;
1331 ret = 1;
1332 out:
1333 free_snapshot_list(&sl);
1334 return ret;
1335 }
1336
1337 static int com_create(void)
1338 {
1339 int ret, status;
1340 char **rsync_argv;
1341
1342 if (conf.dry_run_given) {
1343 int i;
1344 char *msg = NULL;
1345 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1346 for (i = 0; rsync_argv[i]; i++) {
1347 char *tmp = msg;
1348 msg = make_message("%s%s%s", tmp? tmp : "",
1349 tmp? " " : "", rsync_argv[i]);
1350 free(tmp);
1351 }
1352 free_rsync_argv(rsync_argv);
1353 dss_msg("%s\n", msg);
1354 free(msg);
1355 return 1;
1356 }
1357 ret = pre_create_hook();
1358 if (ret < 0)
1359 return ret;
1360 if (create_pid) {
1361 ret = wait_for_process(create_pid, &status);
1362 if (ret < 0)
1363 return ret;
1364 ret = handle_pre_create_hook_exit(status);
1365 if (ret <= 0) /* error, or pre-create failed */
1366 return ret;
1367 }
1368 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1369 ret = create_snapshot(rsync_argv);
1370 if (ret < 0)
1371 goto out;
1372 ret = wait_for_process(create_pid, &status);
1373 if (ret < 0)
1374 goto out;
1375 ret = handle_rsync_exit(status);
1376 if (ret < 0)
1377 goto out;
1378 post_create_hook();
1379 if (create_pid)
1380 ret = wait_for_process(create_pid, &status);
1381 out:
1382 free_rsync_argv(rsync_argv);
1383 return ret;
1384 }
1385
1386 static int com_ls(void)
1387 {
1388 int i;
1389 struct snapshot_list sl;
1390 struct snapshot *s;
1391
1392 dss_get_snapshot_list(&sl);
1393 FOR_EACH_SNAPSHOT(s, i, &sl) {
1394 int64_t d = 0;
1395 if (s->flags & SS_COMPLETE)
1396 d = (s->completion_time - s->creation_time) / 60;
1397 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1398 };
1399 free_snapshot_list(&sl);
1400 return 1;
1401 }
1402
1403 static int setup_signal_handling(void)
1404 {
1405 int ret;
1406
1407 DSS_INFO_LOG("setting up signal handlers\n");
1408 signal_pipe = signal_init(); /* always successful */
1409 ret = install_sighandler(SIGINT);
1410 if (ret < 0)
1411 return ret;
1412 ret = install_sighandler(SIGTERM);
1413 if (ret < 0)
1414 return ret;
1415 return install_sighandler(SIGCHLD);
1416 }
1417
1418 /**
1419 * The main function of dss.
1420 *
1421 * \param argc Usual argument count.
1422 * \param argv Usual argument vector.
1423 */
1424 int main(int argc, char **argv)
1425 {
1426 int ret;
1427 struct cmdline_parser_params params = {
1428 .override = 0,
1429 .initialize = 1,
1430 .check_required = 0,
1431 .check_ambiguity = 0,
1432 .print_errors = 1
1433 };
1434
1435 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1436 ret = parse_config_file(0);
1437 if (ret < 0)
1438 goto out;
1439 if (ret == 0) { /* no config file given */
1440 /*
1441 * Parse the command line options again, but this time check
1442 * that all required options are given.
1443 */
1444 params = (struct cmdline_parser_params) {
1445 .override = 1,
1446 .initialize = 1,
1447 .check_required = 1,
1448 .check_ambiguity = 1,
1449 .print_errors = 1
1450 };
1451 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1452 }
1453 if (conf.daemon_given)
1454 daemon_init();
1455 ret = change_to_dest_dir();
1456 if (ret < 0)
1457 goto out;
1458 dump_dss_config("startup");
1459 ret = setup_signal_handling();
1460 if (ret < 0)
1461 goto out;
1462 ret = call_command_handler();
1463 out:
1464 if (ret < 0)
1465 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1466 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1467 }